Guide to Smartphone Thermal Management: Passive and Active Cooling Technologies in Detail

The cooling technologies used in smartphones serve a critical purpose: they manage and dissipate the excess heat generated during operation, preventing overheating while enabling the device to maintain high performance, ensure user comfort, protect long-term hardware health, and deliver a reliable experience. Without effective cooling, smartphones would quickly become uncomfortably hot, throttle performance severely, degrade components over time, or even shut down for safety reasons.

Heat is an inevitable byproduct of a smartphone’s core functions — primarily from the System-on-Chip (SoC) (CPU, GPU, NPU), but also from 5G modems, fast charging, camera sensors during video recording, displays at high brightness/refresh rates, and other components. As chips become more powerful (higher clock speeds, advanced AI processing, ray-tracing in games), heat output increases significantly, especially in compact, sealed designs with limited natural airflow.

Primary Purposes and Benefits of Cooling Technologies

Cooling systems (both passive and active) address these challenges in several key ways:

  1. Prevent or Delay Thermal Throttling Thermal throttling is the smartphone’s built-in safety mechanism: when internal temperatures exceed safe limits (typically 80–95°C on the SoC die, or surface temps approaching 45–50°C+), the processor automatically reduces clock speeds, voltage, and power draw to lower heat generation. This protects components from damage but causes noticeable slowdowns — dropped frame rates in games, slower app loading, reduced multitasking responsiveness, and stuttering during video editing or AI tasks. Cooling benefit: Effective systems keep temperatures lower for longer, allowing sustained peak performance. For example:
    • Passive methods (vapor chambers, graphite sheets) can extend high-performance bursts by 2–5× in demanding tasks.
    • Active methods (fans, pumped liquid) in gaming phones enable hours of maximum FPS without significant throttling, versus 10–20 minutes in mainstream flagships.
  2. Maintain Sustained High Performance Modern workloads — intensive mobile gaming (e.g., Genshin Impact at ultra 120 FPS, ray-traced titles), on-device AI (real-time image generation, live translation, local LLMs), 8K video recording, heavy multitasking, or 5G hotspot use — generate continuous heat rather than short bursts. Cooling benefit: By spreading or actively removing heat, cooling allows the SoC to run closer to its designed peak clocks for extended periods. This translates to:
    • Smoother, more consistent gameplay (stable high frame rates without drops).
    • Faster AI inference and photo processing.
    • Better multitasking without lag. In 2025–2026 flagships, vapor chambers help sustain performance 20–50% longer than older graphite-only designs.
  3. Improve User Comfort and Safety Overheating makes the phone hot to the touch (especially the back panel or edges near the SoC), which can be uncomfortable during prolonged use (gaming, calls, video watching). Extreme heat also risks minor burns or reduced grip security. Cooling benefit: Heat spreading (e.g., via vapor chambers or graphite) distributes heat evenly across the chassis, keeping peak surface temperatures lower (often <42–45°C under load vs. 50°C+ without good cooling). This makes the phone feel cooler in hand and safer during extended sessions.
  4. Protect Battery Health and Component Longevity High temperatures accelerate battery degradation (lithium-ion cells lose capacity faster above ~40–45°C sustained), increase internal resistance, and can cause swelling or reduced charging efficiency. Prolonged heat also stresses solder joints, adhesives, and other materials, potentially leading to hardware failures over years. Cooling benefit: Lower operating temperatures extend battery lifespan (e.g., retaining more capacity after 2–3 years) and reduce wear on the SoC and other chips. Some advanced systems even enable slightly higher sustained power without risking long-term damage.
  5. Enable Thinner, Slimmer, or More Powerful Designs As manufacturers push for slimmer profiles, higher-performance chips, and features like on-device AI, heat density rises. Effective cooling allows these advancements without compromising usability. Cooling benefit: Ultra-thin vapor chambers, loop heat pipes, or emerging solid-state fans let phones stay slim while handling more power. For example, innovations like 0.3 mm loop heat pipes could enable even thinner future devices capable of intensive tasks without overheating.
  6. Enhance Overall Device Reliability and Experience Cooling reduces emergency shutdowns (when temps hit critical levels), improves charging stability (fast charging slows or pauses if too hot), and supports consistent behavior in hot environments (e.g., summer use in direct sunlight). In gaming phones, it directly translates to a competitive edge (longer sessions, higher scores).

How Different Cooling Technologies Contribute

  • Passive Cooling (graphite sheets, heat pipes, vapor chambers, TIMs): Spread heat quickly and evenly → delay throttling, uniform temps, comfortable feel. Standard in mainstream flagships (e.g., iPhone 17 Pro’s vapor chamber for sustained A19 Pro performance).
  • Active Cooling (built-in fans, pumped liquid, piezoelectric fans): Actively remove heat via forced convection or circulation → extreme sustained performance. Essential in gaming phones (e.g., REDMAGIC 11 Pro’s turbofan + liquid loop for marathon gaming without drops; Infinix’s piezoelectric fan + HydroFlow for silent, efficient heat jets).

In summary, cooling technologies are not just about “keeping the phone cool” — they are essential for unlocking and sustaining the full potential of modern smartphone hardware. They bridge the gap between powerful chips in tiny spaces and practical, enjoyable real-world use, preventing performance cliffs, discomfort, and premature aging. As demands from gaming, AI, and connectivity continue rising in 2025–2026 and beyond, advanced cooling becomes increasingly vital for delivering flagship-level experiences without compromises.

Sources of heat generation in Smartphones

Smartphones generate heat as a natural byproduct of their operation, primarily due to electrical resistance, inefficiencies in energy conversion, and high computational demands in a compact, sealed form factor with limited airflow. Excessive heat leads to thermal throttling (automatic reduction in CPU/GPU clock speeds to lower temperatures), reduced battery longevity over time, uncomfortable surface temperatures, and in extreme cases, temporary shutdowns for safety.

In modern smartphones (as of early 2026), heat sources have intensified with more powerful SoCs, on-device AI processing, higher-refresh-rate displays, advanced cameras, and faster connectivity standards. Below is a detailed breakdown of the primary sources of heat generation, ranked roughly by contribution during typical heavy-use scenarios.

1. System-on-Chip (SoC) / Processor (CPU + GPU + NPU)

This is overwhelmingly the largest heat source in nearly all scenarios.

  • Mechanism: The SoC (e.g., Snapdragon 8 Elite series, Apple A19 Pro, Exynos 2600, Dimensity series) contains billions of transistors switching at gigahertz speeds. Each switch consumes power and generates heat via resistive losses (Joule heating: P = I²R).
    • CPU cores spike during multitasking, app launches, or AI inference.
    • GPU cores heat up dramatically during gaming (ray-tracing, high-FPS titles like Genshin Impact or PUBG at ultra settings).
    • Neural Processing Unit (NPU) generates significant heat during on-device AI tasks (e.g., real-time image generation, voice processing, photo enhancement, or local large language models).
  • Power draw & heat output: Flagship SoCs in 2025–2026 can peak at 10–15 W (bursts) or sustain 6–10 W under load. In gaming phones, sustained loads push toward 20 W+, causing surface temps of 45–56°C without advanced cooling.
  • Real-world impact: Thermal throttling often kicks in after 5–15 minutes of intensive use, dropping performance by 30–70% in mainstream flagships (less in gaming models with fans/liquid cooling).

2. 5G / Modem / Radio Frequency Components

Especially prominent during high-data-throughput activities.

  • Mechanism: 5G (particularly mmWave bands) requires high-power beamforming, multiple antennas, and complex signal processing. Sub-6 GHz 5G is less hot but still hotter than 4G.
    • Poor signal strength forces the modem to boost transmit power → more heat.
    • High upload/download (e.g., 4K streaming, cloud gaming, large file transfers) increases RF amplifier and baseband processing load.
  • Contribution: Up to 20% more heat than 4G equivalents in sustained use (e.g., hotspot tethering or video calls over 5G). mmWave modems can cause rapid localized heating near antennas.
  • Context in 2026: With widespread 5G adoption, this remains a key factor in urban/high-data scenarios.

3. Fast Charging Circuitry & Battery During Charging

A major source when the phone is plugged in, especially with fast/wireless charging.

  • Mechanism: Lithium-ion batteries convert electrical energy inefficiently → heat from internal resistance and chemical reactions.
    • Fast charging (65W–120W wired, 50W+ wireless) uses higher current/voltage → accelerates reactions and resistive heating.
    • Charging circuitry (PMIC, buck converters) also dissipates heat.
    • Aged batteries have higher internal resistance → more heat even at moderate speeds.
  • Worst-case: Charging + heavy use (e.g., gaming while charging) combines SoC heat with charging heat → very high temps (often throttles charging speed or performance).
  • Mitigations: Modern phones pause fast charging or reduce speed above ~40–45°C to protect the battery.

4. Camera Sensors & Image Signal Processor (ISP)

Significant during extended video recording or photography bursts.

  • Mechanism: High-resolution sensors (e.g., 200 MP main, periscope telephoto) and continuous autofocus/exposure processing consume power.
    • 4K/8K video recording at 60+ FPS heats the sensor, ISP, and stabilization hardware.
    • Laser autofocus, ToF sensors, and AI enhancements add load.
  • Typical scenario: 10–30 minutes of 4K/60 recording can raise temps 10–15°C above idle, often the second-hottest spot after the SoC.

5. Display (OLED/AMOLED Panel & Driver IC)

Contributes noticeably during high-brightness or high-refresh-rate use.

  • Mechanism: OLED pixels emit light via current through organic materials → resistive heating.
    • High refresh rates (120–144 Hz) increase driver IC switching.
    • Peak brightness (HDR content, outdoor use) drives more current.
  • Impact: Less than SoC but adds 3–8°C during prolonged bright-screen tasks (e.g., video streaming or navigation in sunlight).

6. Other Minor / Situational Sources

  • Battery during heavy discharge — Rapid discharge (gaming, 5G hotspot) releases heat from internal chemistry.
  • Wireless charging coil — Inductive losses convert to heat (often 5–10 W inefficiency).
  • Haptics / Vibration motor — Minor but adds during gaming.
  • Ambient/environmental heat — External factors (direct sunlight, hot car dashboard, poor ventilation in a case/pocket) compound internal heat, making dissipation harder.

Summary of Heat Generation by Scenario (2025–2026 Flagships/Gaming Phones)

ScenarioPrimary Heat Source(s)Typical Peak Temp RiseNotes / Mitigation Needs
Idle / Light useMinimal (background processes)+5–10°CNegligible
Web browsing / Social mediaSoC + Display + Modem+10–20°CMostly passive cooling suffices
5G streaming / CallsModem + SoC+15–25°C5G signal strength critical
Fast charging (no use)Battery + Charging circuit+15–30°CNormal; slows if too hot
Charging + heavy useSoC + Battery + Charging+30–45°C+High throttling risk; avoid if possible
Gaming (30+ min)SoC (GPU dominant) + Display+30–50°C+Needs vapor chamber/fan/liquid
8K video recordingCamera sensor + ISP + SoC+20–35°COften throttles to 4K
On-device AI (e.g., image gen)NPU + SoC+20–40°CEmerging heavy load in 2026

In 2025–2026 devices, the push for higher performance (e.g., 4+ GHz cores, advanced ray-tracing, larger AI models) means heat generation continues rising, driving adoption of advanced cooling (vapor chambers in flagships, active systems in gaming phones). Manufacturers balance this with software optimizations (dynamic voltage/frequency scaling) to prevent excessive throttling while maintaining slim, silent designs.

Cooling Technologies used in Smartphones

Here is a comprehensive list of the cooling technologies currently used in smartphones (as of early 2026). These are grouped into passive (no moving parts, most common across all categories) and active (with powered components, mainly in gaming/performance-oriented models). Many phones combine multiple technologies in multi-layer stacks for optimal performance.

Passive Cooling Technologies

These rely on conduction, spreading, and natural dissipation without any energy input or moving parts. They form the foundation of thermal management in nearly all modern smartphones.

  1. Graphite Sheets / Graphite Films / Graphene Layers Ultra-thin sheets (often synthetic graphite or graphene-enhanced) with extremely high in-plane thermal conductivity (typically 500–1800 W/m·K). They act as heat spreaders, quickly transferring heat from the processor (SoC) across a larger surface area (motherboard, frame, back panel) to prevent hotspots and allow the phone chassis to radiate heat. Very common in mid-range to flagship phones; often layered in multiple sheets (e.g., 5–9 layers in some designs). Graphene variants offer marginal improvements in some cases. Still widely used even in vapor chamber phones as a complementary layer.
  2. Heat Pipes Thin, sealed copper tubes (usually flattened to ~0.8–1.5 mm) containing a small amount of working fluid (e.g., water) and a wick structure. Heat causes the fluid to evaporate near the hot component → vapor moves to cooler areas → condenses and releases heat → liquid returns via capillary action in the wick. Provides efficient linear (one-dimensional) heat transport. Less common now as standalone solutions but still appear in some designs or as supplements to vapor chambers.
  3. Vapor Chambers (VC) The dominant high-end passive solution today. A flat, thin (typically 0.3–0.6 mm), sealed copper enclosure filled with working fluid and internal wick structures covering the surfaces. Operates on the same phase-change principle as heat pipes but spreads heat two-dimensionally across a large area (often covering much of the motherboard), making it 20–50% more effective at eliminating hotspots than heat pipes or graphite alone in many scenarios. Standard in 2025–2026 flagships:
    • Android flagships (Samsung Galaxy S series, Google Pixel Pro, Xiaomi, etc.)
    • Apple iPhone 17 Pro and later models adopted vapor chambers
    • Almost all gaming phones (RedMagic, ASUS ROG, etc.) use very large vapor chambers as the base layer. Frequently combined with graphite sheets, copper foil, or thermal interface materials (TIMs) in multi-layer systems.
  4. Thermal Interface Materials (TIMs) / Thermal Pastes / Gels Compounds (e.g., advanced pastes, phase-change materials/PCMs, or gels) applied between the processor die and the cooling layer (vapor chamber/graphite) to reduce thermal resistance and improve contact heat transfer. Minor but essential in high-performance designs.
  5. Other Passive Elements
    • Copper foil / stainless steel plates (used in some multi-layer stacks for added conduction).
    • Radiative coatings or advanced materials (emerging but rare in phones).
    • Loop heat pipes / miniature loop heat pipes (mLHP) — ultra-thin variants researched for future slim devices but not yet mainstream.

Active Cooling Technologies

These use power to actively move heat or air, dramatically improving sustained performance during heavy loads (e.g., extended gaming). Primarily found in gaming phones (RedMagic, ASUS ROG, Infinix GT series, etc.).

  1. Built-in Micro Fans / Turbofans Small, high-RPM fans (often 18,000–22,000+ RPM) integrated inside the phone. They force air convection over internal heatsinks, vapor chambers, or graphite layers. Examples:
    • RedMagic series (long-standing feature)
    • ASUS ROG Phone series (GameCool system with AeroActive Cooler accessory options) Provides the most noticeable sustained cooling but can produce audible noise.
  2. Active Liquid Cooling / Pumped Liquid Cooling Closed-loop systems that actively circulate a liquid coolant (often fluorinated or specialized fluids) using micro-pumps. Far more effective than passive vapor chambers for extreme loads. Key examples in 2025–2026:
    • RedMagic 11 Pro — World’s first mass-produced flowing/visible liquid cooling (AquaCore / Golden AquaCore system) with liquid metal enhancements and visible coolant flow through the back panel.
    • Infinix HydroFlow Liquid Cooling — Uses dual piezoelectric ceramic single-pump technology to drive liquid at up to 6.5 ml/min (2× faster than conventional), covering 100% of mainboard hotspots. Often combined with large vapor chambers.
  3. Piezoelectric Fans / Solid-State Fans Brand-new (debuted 2026): ultra-thin (0.1 mm) vibrating sheets using piezoelectric ceramics that pulse at very high frequencies (e.g., 25,000 times/second). Creates high-pressure, turbulent air jets without rotating blades → silent, bladeless forced convection. Claimed to deliver >10× heat dissipation compared to traditional fans in similar space. First introduced by Infinix at CES 2026, often paired with their HydroFlow liquid system for hybrid active cooling.

Summary Table of Cooling Technologies

#TechnologyTypeMain Use CaseTypical Phones (2025–2026)Key Advantage
1Graphite Sheets / GraphenePassiveAll categoriesAlmost every smartphoneThin, cheap, excellent spreading
2Heat PipesPassiveMid-range to some flagshipsOlder or supplementary designsEfficient linear transport
3Vapor ChambersPassiveFlagships & gaming phonesiPhone 17+, Galaxy S, Pixel Pro, all gamingSuperior 2D spreading, mainstream now
4Micro Fans / TurbofansActiveGaming phonesRedMagic, ASUS ROG PhoneStrong sustained performance
5Active Liquid CoolingActiveHigh-end gaming phonesRedMagic 11 Pro, Infinix GT seriesExtreme heat removal, visible in some
6Piezoelectric FansActiveEmerging gaming phonesInfinix (CES 2026 debut)Silent, ultra-thin, high efficiency

Most mainstream flagships rely on passive multi-layer systems (vapor chamber + graphite + TIMs), while gaming phones layer active technologies on top for maximum sustained power without throttling. As chip power and AI workloads continue rising, active and hybrid solutions are becoming more prominent in premium performance devices.

Passive Cooling Technology: Graphite Sheets / Graphite Films / Graphene Layers

Graphite sheets (also called graphite films or thermal graphite sheets) represent one of the most widely adopted and longest-standing passive cooling solutions in smartphones. They have been a staple in thermal management since the mid-2010s and continue to play a major role in 2025–2026 devices, even in phones that also use vapor chambers. These are passive because they require no power, have no moving parts, and rely purely on material properties for heat transfer.

1. What Are Graphite Sheets Made Of and How Are They Produced?

Graphite sheets used in smartphones are almost always synthetic graphite (also called artificial or pyrolytic graphite sheets), not natural mined graphite.

  • Synthetic graphite production process:
    • Starts with a polymer precursor film, most commonly polyimide (PI) film (the same base material used in flexible circuits and Kapton tape).
    • The PI film undergoes high-temperature carbonization in a controlled environment (typically in a vacuum or inert atmosphere) → this decomposes the polymer into carbon.
    • Followed by a graphitization step at extremely high temperatures (often >2500–3000 °C) → this rearranges the carbon atoms into highly ordered, stacked hexagonal layers resembling graphene planes.
    • The result is a thin, flexible, highly oriented graphite sheet with exceptional properties.
  • Thickness: Modern smartphone-grade sheets are ultra-thin, typically 17–50 µm (micrometers), with some advanced ones down to ~10–25 µm. This allows stacking multiple layers without significantly increasing device thickness.
  • Natural graphite (mined and processed into sheets) was used in earlier phones (~2010–2015) but has largely been replaced because:
    • Lower in-plane thermal conductivity (usually 300–700 W/m·K).
    • Thicker profiles.
    • Less consistent quality and purity.

Synthetic versions achieve far superior performance while remaining lightweight (density ~1.8–2.2 g/cm³) and flexible.

2. Key Physical Property: Anisotropic (Directional) Thermal Conductivity

The magic of graphite sheets comes from their anisotropic nature — heat conducts very differently depending on direction.

  • In-plane thermal conductivity (along the X-Y plane of the sheet, parallel to the graphene-like layers): 900–1950 W/m·K (commonly 1500–1900 W/m·K in premium sheets). This is 4–5 times higher than pure copper (~400 W/m·K) and vastly better than aluminum (~200 W/m·K).
  • Through-plane thermal conductivity (Z-direction, perpendicular to the sheet): Only 3–20 W/m·K (often ~5–10 W/m·K). This creates an anisotropic ratio of ~100:1 to 500:1 or higher.

Because heat prefers to travel along the plane (the “easy” direction) rather than through the thickness, the sheet acts as an excellent 2D heat spreader rather than a bulk conductor.

3. Detailed Mechanism: How Graphite Sheets Cool a Smartphone

  1. Heat generation → The main heat source is usually the SoC (processor + GPU), but also the battery during fast charging, 5G modem during heavy data use, camera sensor during 4K/8K video, etc.
  2. Heat transfer to the sheet → A thin layer of thermal interface material (TIM) — such as thermal paste, thermal gel, phase-change material, or adhesive thermal pad — is applied between the hot component (e.g., SoC shield/can) and the graphite sheet. This minimizes air gaps (air is a terrible conductor) and ensures good thermal contact.
  3. Ultra-fast in-plane spreading → Once heat enters the graphite sheet, phonons (heat-carrying vibrations in the lattice) travel extremely rapidly along the highly ordered carbon layers. Heat spreads laterally across the large surface area of the sheet (often covering much of the motherboard, mid-frame, battery area, or even extending toward the display/back panel). This converts a small, intense hotspot (e.g., 80–90°C on the SoC die) into a much larger, uniformly warmer area (e.g., 40–50°C across 50–100 cm²).
  4. Heat dissipation from the phone → The spread-out heat is now conducted to:
    • The metal mid-frame / chassis.
    • The glass or metal back panel.
    • The display assembly. These larger surfaces have much greater contact with ambient air, allowing natural convection and radiation to carry heat away from the phone. The entire device body effectively becomes a low-temperature heatsink.
  5. Temperature equalization effect → By preventing localized overheating, the sheet reduces peak temperatures on the SoC by 10–20°C (or more in stacked configurations) during heavy loads. Lower peak temps delay or reduce thermal throttling, sustaining higher CPU/GPU clocks for longer gaming, video recording, or multitasking.

4. Graphene Layers / Graphene-Enhanced Variants

“Graphene layers” in smartphone marketing often refer to:

  • Graphene-enhanced graphite sheets — synthetic graphite with added graphene flakes or aligned graphene structures to boost in-plane conductivity slightly (up to ~2000+ W/m·K in some claims).
  • Multi-layer graphene films — stacks of few-layer graphene used as a premium alternative or supplement.
  • True single-layer or few-layer graphene is still rare in mass-market phones due to cost and production challenges, but companies like Huawei, Realme, and others have incorporated graphene-based thermal films since ~2018–2019 (e.g., Huawei Mate series, some Realme GT models).

Graphene theoretically offers even higher in-plane conductivity (~3000–5300 W/m·K for ideal single-layer), but real-world implementations in phones are usually composites or thick films, achieving performance similar to or marginally better than top synthetic graphite sheets.

5. Advantages of Graphite Sheets in Smartphones

  • Extremely thin and lightweight — ideal for slim designs.
  • Flexible — conforms to curved batteries, foldable hinges, irregular mid-frames.
  • Low cost compared to vapor chambers (especially in mid-range phones).
  • Passive, silent, reliable — no failure points like fans or pumps.
  • Electromagnetic shielding bonus — blocks some EMI/RFI.
  • Can be stacked in multiple layers (e.g., 3–9 layers in high-end designs) for even better spreading.

6. Limitations

  • Does not “remove” heat — only spreads it. Final dissipation still depends on the phone’s chassis and ambient conditions.
  • Through-plane conductivity is low → needs good contact and TIM to get heat in/out efficiently.
  • Can make the phone’s surface warmer overall during heavy use (heat is distributed, not eliminated).
  • Less effective than vapor chambers for very high heat flux (e.g., sustained 100W+ gaming loads in flagships/gaming phones) → that’s why most 2025–2026 flagships combine both.

Summary

Graphite sheets / films (primarily synthetic) work by leveraging the extraordinary in-plane thermal conductivity of aligned carbon layers to rapidly spread heat from concentrated hotspots across a large area. This equalization lowers peak temperatures, delays throttling, and allows the phone’s entire body to act as a passive radiator. They remain one of the most cost-effective, slim, and reliable passive cooling technologies — used alone in many mid-range phones and as a complementary layer (often directly on or under vapor chambers) in virtually all modern flagships.

Passive Cooling Technology: Heat Pipes

Heat pipes are a highly efficient passive (no moving parts, no external power required) two-phase heat transfer device widely used in electronics for decades. In smartphones, they serve as a compact, reliable way to transport heat away from concentrated hotspots (primarily the SoC/processor) to cooler, more distant areas of the device where it can be dissipated through the chassis.

They predate vapor chambers in smartphones and were a dominant cooling solution from roughly 2014–2020 in many flagships and mid-range phones. By 2025–2026, vapor chambers have largely supplanted standalone heat pipes in high-end flagships due to superior two-dimensional spreading, but heat pipes remain relevant in:

  • Supplementary roles (combined with vapor chambers or graphite).
  • Mid-range/budget phones.
  • Emerging ultra-thin/flexible variants for foldables and future slim designs.

1. Basic Structure and Components of a Heat Pipe

A typical smartphone heat pipe is a sealed, thin copper tube (often flattened to 0.6–1.5 mm thick for slim phones) containing three essential elements:

  • Working fluid — Usually a small amount of low-boiling-point liquid like water, acetone, methanol, or specialized fluids (e.g., ethanol in some designs). The fluid is chosen so its boiling point is well below the operating temperature of smartphone components (typically 40–90°C under load), allowing efficient evaporation even at moderate heat levels.
  • Wick structure — A porous material lining the inner walls (e.g., sintered copper powder, grooved copper, screen mesh, or composite). The wick provides capillary action to return condensed liquid to the hot end against gravity or orientation.
  • Sealed container — High-purity copper (excellent thermal conductivity ~400 W/m·K) or sometimes aluminum/stainless steel. The interior is under vacuum to lower the boiling point of the fluid.

Smartphone versions are flattened (oval or rectangular cross-section) to fit tight spaces, often 1–3 mm wide and 50–150 mm long.

2. Detailed Working Principle (Two-Phase Heat Transfer Cycle)

Heat pipes achieve effective thermal conductivity of 5,000–50,000 W/m·K (effective, along the length) — 10–100× better than solid copper — due to latent heat of vaporization.

  1. Evaporation (hot end / evaporator section) Heat from the SoC (or other component) conducts through thermal interface material (TIM) into the pipe’s wall → raises the temperature of the working fluid → fluid boils/evaporates into vapor, absorbing massive latent heat (hundreds of times more than sensible heat in solids/liquids). This keeps the evaporator section relatively cool despite high heat flux.
  2. Vapor transport (adiabatic section) Vapor pressure drives the low-density vapor rapidly along the hollow core toward the cooler end (pressure gradient). Vapor moves with minimal resistance, carrying heat away efficiently.
  3. Condensation (cold end / condenser section) At the cooler end (far from the SoC, near frame/back panel/battery edges), vapor contacts the cooler wall → condenses back to liquid, releasing the stored latent heat. Heat is conducted through the pipe wall to the phone’s chassis for dissipation via convection/radiation.
  4. Liquid return (via wick) Condensed liquid is wicked back to the evaporator by capillary forces in the porous structure. This return works in any orientation (unlike gravity-dependent thermosiphons), crucial for handheld devices held at various angles.

The cycle is continuous and self-sustaining as long as there’s a temperature difference. No external pump or electricity is needed.

3. Key Advantages in Smartphones

  • Extremely efficient linear heat transport over distances (50–200 mm typical in phones).
  • Compact and lightweight — fits slim profiles.
  • Passive, silent, reliable (no fans, no failure from moving parts).
  • Orientation-independent (capillary wick enables use in any position).
  • Can handle heat fluxes of 10–50 W/cm² in smartphone-scale pipes.

4. Limitations in Smartphone Context

  • One-dimensional transport — Excellent along the pipe length but poor lateral spreading (unlike vapor chambers’ 2D area coverage).
  • Performance drops with bends, length increases, or extreme thinness (<0.5 mm).
  • Wick dry-out risk under very high heat loads or poor orientation (though rare in phones).
  • Less effective than vapor chambers for covering large motherboard areas in modern high-power SoCs.
  • In 2025–2026 flagships, often replaced or supplemented by vapor chambers for better hotspot elimination.

5. Real-World Examples of Heat Pipe Use in Smartphones

  • Early to mid-2010s adoption (widely used before vapor chambers dominated):
    • Samsung Galaxy S7 / S8 series — Featured “Water Carbon Cooling” with heat pipes (thermal spreading pipes) to manage Snapdragon/Exynos heat.
    • Samsung Galaxy Note 9 (2018) — Used one of the largest heat pipes at the time (350 mm³ volume vs. 95 mm³ in S9) for better sustained performance.
    • OPPO Reno 10x Zoom (2019) — Employed a cooling pipe alongside graphite sheets and thermal gel for periscope zoom heat during extended use.
    • LG G6 / V series (2017–2019) — Advanced heat pipe designs to equalize temperatures across the body.
  • Supplementary or hybrid use in 2020s:
    • Many mid-range and some flagship Android phones (e.g., certain Realme, Vivo, Xiaomi models) still include small heat pipes alongside graphite or as part of multi-layer stacks.
    • Gaming/performance phones often combine heat pipes with vapor chambers (e.g., some ASUS ROG or older RedMagic models used heat pipes before shifting to larger vapor + active systems).
  • Emerging / Future-oriented uses (2025–2026 research and prototypes):
    • Ultra-thin loop heat pipes (UTLHP) — Nagoya University (Japan, 2025): 0.3 mm thick loop heat pipes for smartphones/tablets, handling 10 W heat transport, ~45× better than copper, 10× better than graphite sheets. Orientation-independent and suitable for slim designs or gaming/video loads.
    • Flexible heat pipes — Developed for foldable phones (e.g., cross-hinge heat dissipation). Research shows up to 23°C lower chip temps vs. copper foil alone; uses flexible shells + wick for bending without performance loss.
    • Adaptative heat pipes (AHP) — 2025 Nature Communications: Shape-adaptive pipes for complex electronics (e.g., AR/VR headsets, foldables), conforming to 3D paths.
    • Ultra-thin flexible loop heat pipes (UFLHP) — 0.7 mm thick prototypes with powder-sintered wicks, achieving >10,000 W/m·K effective conductivity and 5 W/cm² heat flux — targeted at foldables and space-constrained devices.

Summary

Vapor chambers excel at efficient, passive, two-dimensional heat spreading via phase-change cycling (evaporation → vapor diffusion → condensation → capillary return), far outperforming linear heat pipes or anisotropic graphite for hotspot elimination in compact smartphones. They are now the go-to solution in 2025–2026 flagships — from Apple’s first implementation in iPhone 17 Pro (for sustained A19 Pro power) to Samsung Galaxy S25 Ultra’s enlarged design and gaming beasts like RedMagic 11 Pro’s massive VC base layer. As chips grow more powerful and AI/camera demands rise, vapor chambers enable longer peak performance without active cooling in mainstream premium phones.

Passive Cooling Technology: Thermal Interface Materials (TIMs) / Thermal Pastes / Gels

Thermal Interface Materials (TIMs) are essential passive components in smartphone thermal management systems. They fill microscopic air gaps and surface irregularities between heat-generating components (primarily the SoC/processor die or its shielding can) and the next layer of the cooling stack — such as a vapor chamber, heat pipe, graphite sheet, or copper plate. Air is a very poor thermal conductor (~0.026 W/m·K), so even tiny air pockets create high thermal contact resistance, leading to hotspots and rapid throttling. TIMs replace air with a material of much higher thermal conductivity, drastically reducing interfacial thermal resistance and improving overall heat transfer efficiency.

In smartphones, TIMs are applied in extremely thin layers (often 10–100 µm) to fit tight internal spacing while maximizing contact area. They are passive — no power or moving parts required — and must meet strict requirements: high thermal conductivity, low thermal resistance, good wetting/flow, long-term stability (no drying out or pump-out), non-electrically conductive (in most cases), low outgassing, and compatibility with high-volume automated assembly.

1. Main Types of TIMs Used in Smartphones

Smartphone TIMs fall into several categories, with thermal pastes/greases, thermal gels, and phase-change materials (PCMs) being the most relevant. Pads are less common directly on the SoC due to thickness constraints.

A. Thermal Pastes / Thermal Greases / Thermal Compounds

  • Composition: A viscous mixture of a carrier fluid (usually silicone oil or non-silicone synthetic base) + high loadings of thermally conductive fillers (e.g., zinc oxide, aluminum oxide, boron nitride, aluminum nitride, silver particles).
  • Thermal conductivity: Typically 1–12 W/m·K (consumer-grade ~4–8 W/m·K; premium ~8–12+ W/m·K).
  • Application: Dispensed as a small dot or line on the SoC shield or die, then compressed by the cooling layer (vapor chamber or graphite). The paste flows under pressure to fill micro-gaps.
  • Advantages:
    • Excellent wetting and gap-filling → lowest contact resistance among common TIMs.
    • Very thin bond lines possible (~20–50 µm).
    • High performance for concentrated hotspots.
  • Disadvantages:
    • Can suffer from pump-out (material squeezes out over thermal cycles) or drying out (carrier fluid evaporates or separates), degrading performance over years.
    • Messy during manufacturing; requires precise dispensing.
    • Not ideal for large gaps or uneven surfaces.

B. Thermal Gels

  • Composition: Thixotropic (shear-thinning) materials — behave like a thick gel but flow under dispensing pressure, then recover viscosity. Often silicone-based or non-silicone, filled with similar particles as pastes (alumina, BN, etc.).
  • Thermal conductivity: 3–12 W/m·K (many modern gels reach 8–12 W/m·K).
  • Application: Dispensed via automated needle or screen printing; cures or remains semi-fluid. Often used between SoC shield and vapor chamber.
  • Advantages:
    • Better long-term stability than traditional pastes (less pump-out, minimal separation).
    • Easier to dispense in production (no curing needed in many cases).
    • Good for slightly uneven surfaces or small gaps.
    • Maintains performance over wide temperature cycles.
  • Disadvantages:
    • Slightly higher viscosity than pastes → marginally higher contact resistance in ultra-thin applications.
    • Can still slump if over-applied.

C. Phase-Change Materials (PCMs) / Phase-Change Pads or Films

  • Composition: Polymer matrix + conductive fillers; solid at room temperature, soften/melt at operating temps (typically 45–60°C).
  • Thermal conductivity: 3–8+ W/m·K in the softened state.
  • Application: Pre-applied as thin pads/films on vapor chambers or shields; melts during first use to conform perfectly.
  • Advantages:
    • No pump-out or drying issues — performance stabilizes after initial cycles.
    • Clean application (pre-cut shapes).
    • Excellent for repeated thermal cycling.
  • Disadvantages:
    • Higher initial contact resistance until phase change occurs.
    • Thickness usually >50 µm (less ideal for ultra-slim phones).

D. Liquid Metal TIMs (Advanced / Niche in Smartphones)

  • Composition: Alloys like gallium-indium-tin (Galinstan) or proprietary non-corrosive variants.
  • Thermal conductivity: 20–70 W/m·K — dramatically higher than conventional TIMs.
  • Application: Applied between SoC and vapor chamber in high-end gaming phones.
  • Advantages: Extremely low thermal resistance; can drop temps by 5–15°C.
  • Disadvantages: Electrically conductive (risk of shorts if misapplied), potential corrosion with aluminum, difficult to apply in mass production.

2. How TIMs Work in the Smartphone Cooling Stack

  1. Heat from the SoC die → conducts to the metal shield/can.
  2. TIM layer → fills microscopic roughness and air gaps between shield and the primary cooling element (vapor chamber, graphite, copper plate).
  3. Efficient conduction → heat quickly enters the spreader (vapor chamber/graphite) → spreads across a large area → dissipates via chassis. Without good TIM, even the best vapor chamber loses effectiveness due to high interface resistance.

Typical bond-line thickness: 20–80 µm. Lower thickness + higher conductivity = better performance.

3. Real-World Examples in Smartphones (2025–2026)

  • Mainstream flagships (Samsung, Google Pixel, Apple):
    • Use high-performance thermal gels or advanced pastes between the SoC shield and vapor chamber.
    • Samsung Galaxy S25 series — employs Tailored Thermal Interface Material (TIM) optimized for the large vapor chamber, reducing thermal resistance for Snapdragon 8 Elite sustained loads.
    • Apple iPhone 17 Pro series — integrates a custom thermal gel or paste with the vapor chamber and deionized-water working fluid for efficient A19 Pro heat transfer.
  • Gaming / Performance Phones (RedMagic, ASUS ROG, etc.):
    • RedMagic 11 Pro — Features Liquid Metal 3.0 (non-corrosive liquid metal TIM) placed directly above the massive vapor chamber for ultra-low thermal resistance. Combined with AquaCore flowing liquid cooling and turbo fan.
    • RedMagic 10 Pro / earlier models — Pioneered visible liquid metal cooling systems for extreme gaming loads.
    • ASUS ROG Phone series — Uses premium thermal gels or liquid metal variants between SoC and large vapor chamber + optional external cooler.
  • Chinese performance brands (Realme, iQOO, Xiaomi, etc.):
    • Realme GT series — Incorporates advanced thermal gels and occasionally graphene-enhanced or high-conductivity pastes with vapor chambers and graphite layers.
    • Many models use automated-dispensed gels (e.g., from suppliers like Henkel, Dow, or Parker Chomerics) for consistent high conductivity (8–10+ W/m·K) in mass production.

4. Advantages of TIMs in Smartphones

  • Dramatically lower junction-to-case thermal resistance.
  • Enable longer sustained performance before throttling.
  • Essential for multi-layer cooling stacks (SoC → TIM → VC → graphite → chassis).
  • Compact and lightweight — add negligible thickness/weight.

5. Limitations

  • Performance degrades over time in paste-based TIMs (pump-out, drying).
  • Liquid metal risks (conductivity, corrosion) limit mainstream use.
  • Manufacturing precision required — too much/too little affects performance.
  • Still passive — cannot actively remove heat like fans or pumped loops.

Summary

TIMs (thermal pastes, gels, PCMs, and advanced liquid metals) are the critical “bridge” in smartphone cooling, minimizing thermal resistance at the SoC-to-cooler interface. In 2025–2026, most flagships use high-conductivity gels or tailored pastes with vapor chambers, while gaming phones like RedMagic 11 Pro push boundaries with liquid metal TIMs for extreme loads. They enable modern high-power SoCs to sustain peak clocks longer without severe hotspots, forming an indispensable part of passive thermal stacks.

Passive Cooling Technology: Other Passive Elements

In smartphone thermal management, the “other passive elements” category includes supplementary or emerging passive components that complement the primary technologies (graphite sheets, heat pipes, vapor chambers, and TIMs). These elements enhance heat spreading, conduction, dissipation, or structural thermal paths without requiring power, moving parts, or phase-change mechanisms in the traditional sense (though some involve advanced materials or novel architectures). They are often used in multi-layer stacks, package-level innovations, or to address specific challenges like foldables, ultra-slim designs, or extreme heat flux.

These “other” elements are typically lower-profile than the main spreaders but play crucial supporting roles in achieving uniform temperatures, reducing thermal resistance, or enabling new form factors. As of early 2026, they remain niche or emerging in mass-market phones but show promise for future devices.

1. Copper Foil / Copper Plates / Metal Heat Spreaders

  • Description and Materials:
    • Thin sheets or foils of high-purity copper (thermal conductivity ~400 W/m·K) or occasionally stainless steel variants.
    • Thickness: Often 0.05–0.2 mm for foils; thicker plates in some stacks.
    • Copper excels in isotropic (uniform in all directions) conduction, unlike anisotropic graphite.
  • Mechanism:
    • Acts as a conductive heat spreader or thermal bridge — directly transfers heat from the SoC or vapor chamber to the phone’s metal mid-frame, back panel, or other chassis parts.
    • In multi-layer designs, copper foil is sandwiched between graphite/vapor chamber and the frame to improve through-plane heat flow (where graphite is weak).
    • Stainless steel alternatives offer better mechanical strength and corrosion resistance, though lower conductivity (~15–20 W/m·K), used in emerging high-strength applications.
  • Advantages:
    • Excellent bulk conduction.
    • Durable and integrates well with soldering/brazing.
    • Helps in EMI shielding as a bonus.
  • Limitations:
    • Heavier and thicker than graphite.
    • Less effective for large-area spreading compared to vapor chambers.
    • Costlier in large sheets.
  • Real-World Uses (2025–2026):
    • Many flagships layer thin copper foil under vapor chambers or graphite for enhanced vertical heat transfer (e.g., in Samsung Galaxy S25 series multi-layer stacks).
    • Emerging shift to stainless steel heat spreaders in AI/ML-focused chips for better structural stability (market reports show stainless steel variants growing faster than copper in some segments).
    • Used in foldable phones to bridge hinge areas or reinforce thermal paths.

2. Radiative Coatings / Surface Treatments / Advanced Chassis Materials

  • Description:
    • Special coatings, paints, or material finishes applied to internal or external surfaces (e.g., mid-frame, back glass/metal).
    • Examples: High-emissivity coatings (increasing infrared radiation) or low-reflectivity treatments.
  • Mechanism:
    • Enhances thermal radiation — the phone’s chassis radiates heat more efficiently to the environment (especially in the 8–13 µm infrared window).
    • Passive and always-on; works best in low-airflow scenarios.
  • Advantages:
    • No added thickness or weight.
    • Complements conduction/spreading.
  • Limitations:
    • Minor contribution (~5–15% of total dissipation in typical use).
    • Less effective indoors or in pockets.
  • Real-World Uses:
    • Subtle implementation in many flagships (e.g., optimized back panel materials in iPhone 17 series or Galaxy models for better radiative loss).
    • Emerging research into metamaterials for passive radiative cooling, but not yet mainstream in phones.

3. Package-Level Innovations: Heat Path Block (HPB) / Integrated Metal Heatsinks

  • Description:
    • Samsung’s proprietary Heat Path Block (HPB) — a copper-based metal block integrated directly into the chipset package (e.g., on top of the SoC die in Fan-out Wafer Level Packaging).
    • Acts as an embedded passive heatsink/radiator within the package.
  • Mechanism:
    • Placed directly above the heat source (SoC die) to create a low-resistance thermal path.
    • Transfers heat rapidly upward/outward, bypassing polymer layers (substrates, DAF, EMC) that have poor conductivity.
    • Reduces internal package thermal resistance by up to 16% vs. predecessors.
  • Advantages:
    • Dramatically lowers junction temperatures.
    • Enables higher sustained clocks without throttling.
    • Miniaturizes overall cooling needs (potentially reduces reliance on fans in extreme cases).
  • Limitations:
    • Chipset-specific (requires redesign at packaging stage).
    • Currently Samsung-led, though licensing rumored.
  • Real-World Uses (2025–2026):
    • Debuted in Samsung Exynos 2600 (first 2nm GAA chipset) — improves thermal efficiency for sustained performance.
    • Rumored adoption in Qualcomm Snapdragon 8 Elite Gen 6 series (potentially for Galaxy S27 non-foldables).
    • Interest from Apple and others for future A-series/M-series chips to handle AI workloads.

4. Loop Heat Pipes (LHPs) / Miniature Loop Heat Pipes (mLHPs) / Ultra-Thin Flexible Variants

  • Description:
    • Advanced evolution of heat pipes: Closed-loop system with separate vapor/liquid lines, evaporator, and condenser.
    • Ultra-thin versions (0.3–0.7 mm) use sintered copper powder wicks, laser-welded copper sheets, and fluids like water or ethanol.
  • Mechanism:
    • Phase-change loop: Evaporation at hot end → vapor flows through dedicated path → condensation at cool end → liquid returns via wick.
    • Loop design allows longer-distance transport, better gravity/orientation independence, and flexibility (for foldables).
  • Advantages:
    • 10–45× better effective conductivity than copper or graphite.
    • Handles 5–10 W+ in slim profiles.
    • Flexible variants bend without major performance loss.
  • Limitations:
    • More complex/expensive to manufacture.
    • Still emerging; not yet widespread in mass-market phones.
  • Real-World Uses (2025–2026):
    • Research prototypes from Nagoya University: 0.3 mm ultra-thin loop heat pipe (UTLHP) for smartphones/tablets — transports 10 W stably in any orientation.
    • Ultra-thin flexible loop heat pipes (UFLHP, 0.7 mm) for foldables — addresses cross-hinge heat transfer (up to 5–7 W/cm² flux, effective conductivity >10,000–24,000 W/m·K).
    • Potential in future foldables (e.g., Samsung Galaxy Z series successors) or slim non-foldables.

Summary

“Other passive elements” fill gaps in primary cooling stacks by improving conduction (copper foils/plates), radiation (coatings), package-level paths (HPB), or advanced transport (loop heat pipes). In 2025–2026:

  • Copper foils and HPB dominate in flagships for efficiency gains.
  • Loop heat pipes show strong promise for foldables and ultra-slim future devices.
  • These elements are often combined in hybrid multi-layer designs to push sustained performance higher without active cooling in mainstream phones.

As chip power (especially for on-device AI) continues rising, these supplementary passive solutions help maintain slim, silent, reliable designs while minimizing throttling.

Active Cooling Technology: Built-in Micro Fans / Turbofans

Built-in micro fans (also called turbofans, turbo fans, or internal cooling fans) represent the most aggressive form of active cooling in smartphones. Unlike all passive methods (which rely solely on conduction, spreading, and natural dissipation), these small, high-speed electric fans actively move air to force convection — drawing in cooler ambient air, blowing it across internal heatsinks or thermal layers, and expelling hot air. This dramatically improves heat removal during prolonged high-load scenarios, such as extended gaming sessions at maximum graphics/FPS, ray-tracing enabled titles, or heavy AI/multitasking workloads.

These fans are exclusive to gaming/performance-oriented smartphones (primarily from brands like REDMAGIC/Nubia, with occasional experiments from others). Mainstream flagships (Samsung Galaxy, Google Pixel, iPhone, etc.) avoid them due to added thickness, weight, potential noise, dust ingress concerns, and the fact that passive systems suffice for typical use.

1. Basic Structure and Components

A smartphone turbofan is a miniature centrifugal or axial fan optimized for extreme thinness and efficiency:

  • Size and Design: Diameter typically 10–20 mm; overall thickness contribution ~1–2 mm to the phone’s profile. Centrifugal (radial) designs are common — air is drawn in axially (from the back/side) and expelled radially through vents.
  • Motor: Brushless DC motor (BLDC) for longevity, low vibration, and high RPM capability. Speeds range from 18,000–24,000+ RPM (higher than most laptop fans).
  • Fan Blades: Optimized aerofoil shapes (often 7–11 blades) for maximum airflow (CFM) at minimal noise and power draw. Recent models feature redesigned blades for 20–40% better airflow, improved dust resistance (e.g., via coatings or geometry), and reduced noise (up to 50% quieter in some 2026 implementations).
  • Integration: Mounted on an aluminum bracket or heatsink for structural support and additional passive conduction. Often visible through a transparent or RGB-lit rear panel (with customizable lighting synced to gaming modes).
  • Power and Control: Draws minimal power (~0.5–2 W at peak) from the battery. Controlled via software (e.g., Game Space app) — auto-activates based on temperature/CPU load, or manual toggle. Many support multiple speeds (balanced, performance, extreme).
  • Waterproofing: In 2025–2026 models, fans are often sealed (e.g., IPX8-rated phone body with independent fan module) to prevent water/dust damage.

2. Detailed Working Principle (Forced Convection)

  1. Heat Detection — Sensors monitor SoC, battery, and surface temps.
  2. Fan Activation — At thresholds (e.g., 45–55°C on SoC), the fan spins up.
  3. Airflow Path —
    • Draws cooler external air through intake vents (often side or rear grille).
    • Forces air directly over/through vapor chamber, graphite layers, copper heatsinks, or liquid cooling channels.
    • Expels hot air via exhaust vents (usually rear or side).
  4. Enhanced Heat Transfer — Forced convection coefficient is 10–50× higher than natural convection, rapidly lowering internal temps by 10–25°C (or more) compared to passive-only.
  5. Performance Impact — Sustains peak clocks/FPS 2–3× longer (e.g., 60+ minutes of max-load gaming vs. 15–30 minutes before throttling on passive flagships).

This creates a hybrid system: fan + large vapor chamber + graphite/liquid metal → extreme sustained performance.

3. Key Advantages in Smartphones

  • Dramatic sustained performance — Virtually eliminates thermal throttling in demanding games (e.g., Genshin Impact, Wuthering Waves at ultra settings 90–120 FPS for hours).
  • Lower surface temperatures — Keeps the phone comfortable to hold (often <40°C back panel vs. 45–50°C+ passive).
  • Customizable — RGB lighting, speed profiles, auto modes.
  • Synergy with other tech — Boosts effectiveness of vapor chambers/liquid cooling by actively refreshing the air boundary layer.

4. Limitations

  • Audible noise — High-RPM fans produce whooshing/whirring (though 2026 models are quieter via blade redesign and better balancing).
  • Added thickness/weight — Phones are thicker (8–9.5 mm) and heavier (200–230 g) than mainstream flagships.
  • Dust accumulation — Requires occasional cleaning (some models improve resistance).
  • Battery drain — Minor but present during extended use.
  • Niche appeal — Overkill for non-gaming; mainstream brands avoid due to design compromises.

5. Real-World Examples in Smartphones (2025–2026)

Built-in turbofans remain a signature of gaming phones, led by REDMAGIC (Nubia/ZTE).

  • REDMAGIC 11 Pro (late 2025 / global 2026) Features TurboFan 4.0 at 24,000 RPM (1,000 RPM faster than prior gen). Waterproof (IPX8 phone body), mounted with RGB lighting visible through rear panel. Paired with world’s first mass-produced flowing liquid cooling (AquaCore fluorinated loop), 13,116 mm² vapor chamber, Liquid Metal 3.0 TIM. Enables “PC-level” sustained performance (e.g., 60 FPS Honkai: Star Rail ultra, ray-tracing in multiple titles). Often called the “coolest” phone of 2025–2026 due to hybrid active/passive stack.
  • REDMAGIC 11 Air (January 2026) Slimmer variant (7.85 mm thick, 207 g) with 24,000 RPM Turbo Fan 4.0 (redesigned blades: +21% airflow, +40% sweep area, 30% better dust resistance, 50% less noise). Uses ICEWIND 4.0 system + ultra-thick vapor chamber. Snapdragon 8 Elite powered; sustains high FPS in demanding games while staying lightweight. Proves fans can fit in thinner designs.
  • Earlier / Related Models:
    • REDMAGIC 10 Pro / 10S Pro (2025) — Pioneered visible fan + liquid metal; 23,000 RPM TurboFan.
    • REDMAGIC series since 2019 (RedMagic 3 was the first phone with built-in fan) — Consistent leader in active fan tech.
  • Other Brands (Limited / Experimental):
    • OPPO K13 Turbo / K13 Turbo Pro (2025) — Integrated active cooling fan in camera module (Storm Engine), waterproof ratings (IPX6/8/9 excluding fan area). Focuses on esports-level stability.
    • Xiaomi / Redmi — Rumors/leaks of built-in fan in Redmi K90 Ultra (2026), potentially in camera island, with massive battery (8,500 mAh+).
    • Huawei — Patents for fan-enabled camera hump in Mate series (conceptual, not mass-produced as of early 2026).
    • ASUS ROG Phone series (e.g., ROG Phone 9 Pro, 2025–2026) — Relies on GameCool 9 (advanced passive + vapor chamber) + optional clip-on AeroActive Cooler X Pro (external fan with thermoelectric cooling). No built-in internal fan in recent models; focuses on accessory ecosystem.

Summary

Built-in micro turbofans provide the strongest active forced-air cooling in smartphones, spinning at 18,000–24,000+ RPM to force convection and sustain peak performance far longer than passive systems alone. In 2025–2026, REDMAGIC dominates with models like the 11 Pro (24,000 RPM TurboFan + liquid cooling) and 11 Air (slim fan design), making them ideal for hardcore mobile gamers who prioritize zero-throttling marathon sessions. While noisy and niche, these fans — often combined with massive vapor chambers and liquid metal — push mobile thermal limits, enabling “PC-grade” gaming on the go. Other brands experiment (OPPO, Xiaomi rumors), but REDMAGIC remains the benchmark for integrated turbofan technology.

Active Cooling Technology: Active Liquid Cooling / Pumped Liquid Cooling

Active liquid cooling (also called pumped liquid cooling or circulating liquid cooling) represents one of the most advanced and aggressive active thermal management solutions in smartphones as of early 2026. Unlike passive vapor chambers or heat pipes (which rely on natural phase-change and capillary action without power input), active liquid cooling uses powered micro-pumps to forcefully circulate a liquid coolant through dedicated channels or loops. This creates forced convection within the liquid, rapidly transferring heat from hotspots (SoC, battery, modem) to cooler areas or heatsinks, where it dissipates more effectively.

This technology draws inspiration from desktop PC water-cooling loops but is miniaturized to extreme levels (micron-scale channels, sub-millimeter pumps) to fit inside slim phones. It is exclusive to high-end gaming/performance smartphones because it adds complexity, cost, slight thickness/weight, and power draw — trade-offs unacceptable in mainstream flagships (e.g., iPhone, Galaxy S, Pixel) where passive vapor chambers + graphite suffice for typical loads.

1. Basic Structure and Components

A typical smartphone active liquid cooling system includes:

  • Coolant — Usually a fluorinated liquid (non-conductive, non-corrosive, low freezing/boiling point, high thermal capacity). Examples: “AI-server-grade” fluorinated fluids (used by REDMAGIC) that operate from -40°C to +70°C or wider ranges (-60°C to +108°C in some claims). The liquid is non-electrically conductive to prevent shorts if a leak occurs (though systems are fully sealed).
  • Micro-pumps — Tiny piezoelectric ceramic pumps (most common in 2025–2026 designs). These use electric current to deform piezoelectric ceramics at high frequency → creating pressure waves that drive fluid flow without rotating parts (silent, reliable, low power ~0.1–0.5 W).
    • Flow rates: Up to 6.5 ml/min (Infinix) or similar in REDMAGIC.
    • Dual-pump or single-pump designs for redundancy/efficiency.
  • Closed-loop channels / tubing — Micron-level micro-channels etched or molded into a plate (e.g., “AquaCore” plate) or flexible tubing. Channels snake across the motherboard, covering SoC, battery, and other hotspots (often 100% coverage claimed).
  • Heat exchanger / dissipation area — Liquid carries heat to a large vapor chamber, copper heatsink, graphite layers, or directly to the chassis/back panel. In some designs, combined with built-in fans for hybrid air-liquid cooling.
  • Sealing & Durability — Fully sealed, leak-proof systems with anti-puncture membranes. Passed “tens of thousands of drop tests” in production models. Often integrated into a single peel-off module with fan/wireless charging coil.
  • Control — Software-managed (e.g., Game Space app) — activates on high load/temp, variable speed/flow.

2. Detailed Working Principle (Forced Liquid Convection + Phase Assistance)

  1. Heat Detection — Thermal sensors trigger the pump at thresholds (e.g., SoC >50–60°C during gaming).
  2. Pumping — Piezoelectric deformation creates pressure → circulates coolant at high speed through channels.
  3. Heat Absorption — Liquid flows over/near hotspots → absorbs heat via convection (high specific heat capacity of liquid >> air).
    • Some designs allow minor phase change (evaporation in channels), but primary mechanism is forced liquid flow (not passive vapor chamber boiling).
  4. Heat Transport — Hot liquid moves to cooler zones (e.g., edges, vapor chamber area) → transfers heat to spreader/chassis.
  5. Heat Dissipation — Heat radiates/convects from phone body; some systems use fans to blow air over the loop for extra cooling.
  6. Return Cycle — Cooled liquid recirculates continuously.

This achieves 2× faster flow than “conventional” (passive or earlier) liquid systems, dropping SoC temps by 10–20°C+ vs. passive-only, enabling sustained peak performance (e.g., 120 FPS gaming for hours without throttling).

3. Key Advantages in Smartphones

  • Extreme sustained performance — Handles 20–40 W+ loads indefinitely (vs. throttling after 15–30 min passive).
  • Lower peak temperatures — Keeps SoC/battery cooler, improves longevity and touch comfort.
  • Hybrid potential — Often paired with fans/vapor chambers for triple/quad cooling.
  • Visible appeal — Flowing liquid (blue coolant) through transparent panels creates a futuristic look.

4. Limitations

  • Complexity & Cost — Adds manufacturing difficulty; limited to premium gaming phones.
  • Power draw — Pumps consume battery (minor but present).
  • Thickness/Weight — Adds ~0.5–1 mm vs. passive designs.
  • Reliability concerns — Though sealed and tested, long-term leak risk (theoretical) vs. passive.
  • Niche — Overkill for non-gaming; not in mainstream flagships.

5. Real-World Examples in Smartphones (2025–2026)

Active pumped liquid cooling debuted in mass production in late 2025, pioneered by gaming brands.

  • REDMAGIC 11 Pro (launched late 2025, global availability 2026) World’s first mass-produced smartphone with flowing liquid cooling (AquaCore Cooling System).
    • Uses piezoelectric ceramic micropumps to circulate blue “AI-server-grade” fluorinated liquid through micro-channels in a visible AquaCore plate (seen through transparent rear panel in Nightfreeze/Subzero variants).
    • Combined with 24,000 RPM turbofan, 13,116 mm² vapor chamber, and Liquid Metal 3.0 TIM.
    • Covers SoC (Snapdragon 8 Elite Gen 5) and battery; leak-proof, drop-tested extensively.
    • Enables “PC-level” sustained gaming (e.g., ultra ray-traced titles at high FPS without throttling).
    • Battery: 7,500 mAh; IPX8 water resistance despite fan/liquid.
    • Priced from ~$749; widely reviewed as the “coolest” and fastest gaming phone of 2025–2026.
  • REDMAGIC 11 Air (early 2026) Slimmer variant (7.85 mm thick) retains active cooling elements, including liquid aspects in hybrid setup, but focuses more on fan + vapor chamber for balance.
  • Infinix HydroFlow Liquid Cooling Architecture (debuted CES 2026, first in Note 60 series) Industry-first Dual-Piezoelectric-Ceramic Single-Pump Technology drives fluorinated liquid at up to 6.5 ml/min (2× faster than conventional active liquid cooling).
    • Channels achieve 100% coverage of mainboard hotspots for precision cooling.
    • Hybrid with world’s first smartphone piezoelectric fan (bladeless, 0.1 mm vibrating sheet pulsing 25,000×/second for silent air assist).
    • Targets sustained gaming/AI workloads; claimed >10× heat dissipation efficiency in combo.
    • Paired with modular gaming accessories (pressure-sensitive controllers, magnetic triggers).
    • Positioned for upcoming Infinix gaming/performance models (e.g., GT series successors or Note 60 gaming variants).

No other brands have mass-produced true pumped liquid cooling yet (2026); earlier concepts (e.g., OnePlus 11 Concept’s Active CryoFlux in 2023) were prototypes only. Most gaming phones still rely on large vapor chambers + fans (ASUS ROG, older REDMAGIC), with “liquid cooling” marketing often meaning passive vapor/heat pipes + gel.

Summary

Active/pumped liquid cooling uses piezoelectric micro-pumps to circulate fluorinated coolant through micro-channels, providing forced convection far superior to passive systems for extreme sustained loads. In 2025–2026, it’s led by REDMAGIC 11 Pro (visible flowing AquaCore loop + fan + massive VC) as the first mass-produced implementation, followed by Infinix HydroFlow (dual-piezo pump + bladeless fan hybrid) at CES 2026. These enable marathon high-FPS gaming without throttling, but remain niche to gaming phones due to added complexity. As on-device AI and powerful chips push thermal limits, expect more adoption in performance tiers.

Active Cooling Technologies: Piezoelectric Fans / Solid-State Fans

Piezoelectric fans (also marketed as solid-state fans, bladeless fans, or ultrasonic/vibrating sheet fans) are an emerging class of active cooling technology in smartphones. They represent a bladeless, solid-state alternative to traditional rotating micro-fans (turbofans), using the piezoelectric effect to generate airflow without any moving mechanical parts like blades or motors. This makes them ultra-thin, silent, highly reliable, and energy-efficient compared to spinning fans.

As of February 2026, this technology is in its very early adoption phase in consumer smartphones — primarily showcased as a breakthrough innovation rather than widespread deployment. It is positioned for high-performance gaming and AI-heavy devices where sustained cooling is critical without the noise, dust issues, or thickness penalties of conventional fans.

1. Basic Structure and Components

A piezoelectric fan in a smartphone context typically consists of:

  • Piezoelectric material layer — A thin sheet or membrane made of piezoelectric ceramics (e.g., lead zirconate titanate/PZT or advanced lead-free variants). These materials deform (expand/contract) when an electric voltage is applied.
  • Ultra-thin vibrating sheet — The core element: often 0.1 mm thick (half the thickness of a human hair, ~50–100 µm). This sheet is mounted or etched onto a substrate and can be silicon-based or composite.
  • Electrodes — Thin conductive layers on both sides of the piezo material to apply alternating current (AC) voltage.
  • Mounting/integration — Attached near or integrated into the thermal stack (e.g., over vapor chamber, graphite layers, or liquid cooling channels). Often part of a hybrid system with liquid cooling.
  • Driver circuitry — Small IC that generates high-frequency AC signals (typically ultrasonic range) to drive vibration.
  • Airflow path — No enclosed fan housing; the vibration creates directed air jets or turbulent flow over heatsinks/internal surfaces, with vents in the chassis for intake/exhaust.

No rotating parts → classified as solid-state (like solid-state drives vs. HDDs with moving heads).

2. Detailed Working Principle (Piezoelectric Vibration → Airflow)

The piezoelectric effect is key: certain materials generate mechanical strain (deformation) under an applied electric field, and vice versa.

  1. Electrical excitation — An AC voltage (high frequency, low amplitude) is applied to the electrodes → causes the piezo sheet to vibrate or flex rapidly.
  2. Vibration frequency — Typically ultrasonic (e.g., 25,000 times per second / 25 kHz), far above human hearing (20 Hz–20 kHz).
  3. Air displacement — Each vibration cycle displaces a thin boundary layer of air → creates high-pressure, turbulent air jets or acoustic streaming. This is not a large volume of air like a traditional fan but focused, high-velocity micro-jets.
  4. Forced convection — The jets impinge on hot surfaces (vapor chamber, copper heatsink, motherboard) → disrupt the stagnant thermal boundary layer → dramatically increase the convective heat transfer coefficient (often 5–10× higher than natural convection, and claimed >10× vs. traditional spinning blades in efficiency for equivalent space).
  5. Heat removal — Hot air is pushed toward chassis vents or cooler zones; the system runs continuously or ramps up based on thermal sensors/load.
  6. Efficiency & silence — No bearings, no friction → near-zero mechanical noise, very low power (~0.1–0.5 W), high reliability (no wear-out), and dust resistance (no intake of large particles).

This is distinct from passive piezo cooling (rare experimental) — it is active because it requires electrical power to drive the vibration.

3. Key Advantages in Smartphones

  • Near-silent operation — Ultrasonic frequencies + no blades = virtually inaudible (major upgrade over 20,000+ RPM turbofans).
  • Ultra-thin profile — 0.1 mm sheet adds negligible thickness; ideal for slim gaming phones.
  • High efficiency in confined space — Claims of >10× heat dissipation vs. spinning blades (per Infinix marketing) due to turbulent jets and no dead zones.
  • Reliability & longevity — Solid-state design → no mechanical failure points; withstands drops/vibration better.
  • Low power & dust-resistant — Minimal battery impact; less prone to clogging.
  • Hybrid synergy — Pairs excellently with pumped liquid cooling for combined liquid + air active cooling.

4. Limitations

  • Lower airflow volume — Jets are focused/turbulent but move less total CFM than high-RPM turbofans → best for targeted hotspot cooling rather than broad airflow.
  • Early stage — As of February 2026, mostly prototype/showcase tech; real-world sustained performance data limited.
  • Power draw — Still consumes battery (though low).
  • Manufacturing complexity — Piezo materials and high-frequency drivers add cost.
  • Niche — Only in gaming/performance phones; overkill for mainstream.

5. Real-World Examples in Smartphones (as of February 2026)

Piezoelectric/solid-state fans in smartphones are brand-new, with the first implementations debuting at CES 2026 (January 2026).

  • Infinix HydroFlow Liquid Cooling Architecture + Piezoelectric Fan (CES 2026 debut) Infinix introduced the world’s first smartphone-integrated piezoelectric fan as part of its HydroFlow system.
    • Key specs: 0.1 mm ultra-thin vibrating sheet (half human hair thickness), pulses at 25,000 times/second, creates high-pressure turbulent air jets.
    • Claimed benefits: >10× greater heat dissipation efficiency than traditional spinning blades; near-silent solid-state operation.
    • Integrated with Dual-Piezoelectric-Ceramic Single-Pump liquid cooling (fluorinated liquid at up to 6.5 ml/min, 2× faster than conventional active liquid, 100% mainboard hotspot coverage).
    • Forms a hybrid liquid + active air system for “all-in-one” cooling — combines pumped liquid convection with bladeless air jets for superior sustained performance and cooler touch feel.
    • Showcased alongside satellite comms, modular gaming controllers, and magnetic accessories.
    • Targeted for upcoming models (e.g., Infinix Note 60 series or GT gaming line successors, expected later 2026).
    • Won multiple “Best of CES 2026” awards (e.g., Trusted Reviews Innovation Award, Android Headlines Best of CES) for thermal breakthroughs.
    • Positioned as redefining gaming/AI performance by overcoming passive limits without noisy fans.
  • xMEMS μCooling / AirJet Technology (pre-2026 development, smartphone targeted) xMEMS Labs developed the XMC-2400 μCooling chip — a silicon-based “fan-on-a-chip” using piezoelectric MEMS membranes (8 tiny piezo flaps).
    • Thickness: ~1.08 mm; size ~9.26 × 7.6 mm.
    • Generates airflow via ultrasonic vibrations (shockwave-like pulses).
    • Samples to OEMs started early 2025; first consumer smartphones/tablets expected 2026.
    • Aimed at AI-ready mobile devices to prevent overheating in thin designs (also for laptops, VR, SSDs).
    • Not yet in a released phone as of February 2026, but represents the broader solid-state piezo fan trend.

No other brands have announced or shipped piezoelectric fans in smartphones by February 2026. Earlier piezo concepts (e.g., Frore AirJet for laptops/SSDs) influenced the tech but were not phone-integrated. Infinix holds the distinction of the first announced smartphone-specific implementation.

Summary

Piezoelectric / solid-state fans use high-frequency vibration of ultra-thin piezo sheets to generate silent, efficient air jets for forced convection — a bladeless evolution of active cooling. They excel in silence, thinness, and reliability, making them ideal for future slim gaming phones. In February 2026, Infinix’s CES 2026 piezoelectric fan (0.1 mm sheet, 25 kHz pulsing, hybrid with HydroFlow liquid cooling) is the pioneering real-world showcase, promising >10× dissipation gains and near-silent operation for sustained high loads. Combined with xMEMS-style chip developments targeting 2026 launches, this technology could soon challenge rotating fans in performance devices, especially as AI workloads push thermal boundaries further.

Other / Emerging Techniques in Smartphone Cooling

Beyond the established passive technologies (graphite sheets, heat pipes, vapor chambers, thermal interface materials) and active systems (micro fans, pumped liquid cooling, piezoelectric fans), smartphone thermal management continues to evolve with innovative supplementary or next-generation approaches. These “other” or emerging techniques focus on:

  • Package-level integration (cooling built directly into the chipset itself)
  • Advanced materials and direct-contact solutions
  • Ultra-thin/flexible variants for foldables and slimmer designs
  • Hybrid or novel phase-change enhancements
  • Research-stage concepts pushing boundaries for future devices

These are often layered with primary cooling (e.g., vapor chambers) or targeted at specific challenges like extreme AI workloads, foldable hinge heat transfer, or ultra-compact form factors. As of February 2026, many remain in flagship/gaming implementations, research prototypes, or early adoption, driven by rising power density from 2nm/3nm chips, on-device AI, and high-refresh gaming.

1. Heat Path Block (HPB) / Package-Level Embedded Heatsinks

Description and Mechanism Samsung’s Heat Path Block (HPB) is a groundbreaking package-level thermal solution — a copper-based metal block (heatsink) integrated directly atop the SoC die within the Fan-out Wafer Level Packaging (FoWLP) structure.

  • Traditional packages stack DRAM or other components over the SoC, trapping heat in polymer layers (substrates, die attach film/DAF, epoxy molding compound/EMC) with poor conductivity (~0.5–2 W/m·K).
  • HPB repositions heat paths: a high-conductivity copper layer (~400 W/m·K) sits directly above the heat source → creates a low-resistance vertical escape route for heat → transfers it upward/outward to vapor chambers, graphite, or chassis.
  • Combined with High-k EMC (enhanced thermal conductivity molding compound), it reduces internal package thermal resistance by up to 16% vs. predecessors.

This allows higher sustained clocks (less throttling), better thermal headroom for AI/GPU bursts, and potentially eliminates need for extreme add-ons like fans in some designs.

Advantages

  • Chip-level efficiency gain (not reliant on external spreaders).
  • Enables sustained performance in slim phones.
  • Reduces junction temperatures → longer battery life and component reliability.

Real-World / Emerging Uses (2025–2026)

  • Debuted in Samsung Exynos 2600 (first 2nm GAA chipset, announced 2026) — improves thermal dissipation for sustained high loads.
  • Rumored licensing/adoption: Qualcomm Snapdragon 8 Elite Gen 6 series (schematic leaks show HPB-like structure); potential interest from Apple and others for A-series chips facing AI thermal challenges.
  • Tipsters claim it could reduce reliance on custom fans in gaming phones by providing superior baseline heat escape from the die.

2. Liquid Metal Alloys / Enhanced Thermal Interface Materials (Direct Die Contact)

Description and Mechanism Liquid metal TIMs (e.g., gallium-indium-tin alloys like Galinstan or proprietary variants) offer thermal conductivity of 20–70 W/m·K — far beyond traditional pastes/gels (4–12 W/m·K).

  • Applied as a thin layer between SoC die/shield and vapor chamber/graphite.
  • Provides near-perfect contact → minimizes interfacial resistance → drops temps 5–15°C in high-flux scenarios.
  • Gaming-focused variants (e.g., “Liquid Metal 3.0”) use stabilized, non-corrosive formulas for safer mass production.

Advantages

  • Extreme heat transfer for peak loads.
  • Complements vapor chambers/fans in sustained gaming.

Real-World Uses

  • REDMAGIC series (e.g., REDMAGIC 11 Pro / 10S Pro) — Liquid Metal 3.0 placed directly over the SoC in ICE-X system → lowers CPU temps ~5°C vs. prior versions.
  • Combined with AquaCore flowing liquid and turbofan for hybrid extreme cooling.

3. Ultra-Thin / Flexible Loop Heat Pipes (UTLHP / UFLHP)

Description and Mechanism Loop heat pipes (LHPs) are advanced two-phase systems with separate vapor/liquid lines, evaporator, and condenser — more efficient over distance and orientation-independent than standard heat pipes. Emerging variants are ultra-thin and flexible:

  • Thickness: 0.3–0.7 mm (Nagoya University UTLHP at 0.3 mm; flexible UFLHP at 0.7 mm).
  • Use sintered copper powder wicks (0.4 mm thick), ethanol/water fluid, laser-welded copper sheets.
  • Effective conductivity: 10,000–24,000 W/m·K (45× copper, 10× graphite).
  • Handle 5–10 W+; stable under bending (e.g., 90° fold) with thermal resistance ~2–2.5 K/W.

Advantages

  • Ideal for foldables (cross-hinge heat transfer without performance loss).
  • Enables slimmer non-foldables with high loads.

Real-World / Research Uses

  • Prototypes from Nagoya University (2025): 0.3 mm UTLHP transports 10 W in any orientation → targeted at smartphones/tablets.
  • Ultra-thin flexible LHPs (0.7 mm) for foldables/wearables — handles 7 W/cm² flux, stable under bending.
  • Emerging for future Samsung Galaxy Z series or slim flagships (not yet mass-produced in phones as of Feb 2026).

4. Other Emerging / Research Directions

  • Ionic / Solid-State Airflow Enhancements — Concepts like ionic wind (electrohydrodynamic airflow) or advanced MEMS-based micro-blowers (e.g., xMEMS μCooling chip, 1 mm thin) for targeted cooling in ultra-slim devices (smart glasses, foldables). Samples to OEMs in 2025; expected in phones 2026+.
  • High-k / Advanced EMC and Materials — Enhanced molding compounds with better conductivity in packages → pairs with HPB.
  • Hybrid Passive-Active Integration — e.g., Infinix HydroFlow (2026) combines pumped liquid + piezoelectric fan; REDMAGIC AquaCore visible flowing liquid (2025).
  • Radiative / Metamaterial Coatings — Experimental high-emissivity surfaces for better passive radiation (minor but stacking benefit).

Summary

These emerging techniques shift focus from external add-ons to integrated, chip-level, or form-factor-optimized solutions:

  • HPB (Samsung Exynos 2600, potential Snapdragon adoption) → package-embedded heatsink for baseline efficiency gains.
  • Liquid metal TIMs (REDMAGIC) → extreme interface performance.
  • Ultra-thin/flexible loop heat pipes (research/prototypes) → foldable/slim future-proofing.

As AI workloads, 2nm+ nodes, and foldables push thermal limits in 2026+, these innovations help sustain performance in compact designs without relying solely on bulky active systems. Many are transitioning from labs to flagships/gaming phones, promising cooler, more powerful devices ahead.

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