TL;DR:
A heat sink is a passive cooling component used in electronics to dissipate heat and maintain safe operating temperatures. It works by transferring heat away from devices (like chips or power modules) into the surrounding air through conduction and convection. Effective heat sink performance depends on smart design choices—such as surface area, fin structure, airflow, and thermal interface efficiency. Common types include passive, active, and liquid-cooled heat sinks, typically made from high thermal conductivity materials like aluminum or copper. They are widely used in applications ranging from consumer electronics to EV power systems and aerospace equipment to ensure reliability and prevent overheating.
What Is a Heat Sink in Electronics
Heat sink is used for cooling device to heat dissipation, transferring heat from a high-temperature surface to the surrounding air through thermal conduction. It made from like aluminum thermal conductivity and copper thermal conductivity, offer superior heat transfer coefficient. In addition, effective heat transfer requires good thermal contact between the heat sink and the heat source in ceramic PCB design. With the electronics components become tiny, having high properties. The conventional method of hear transfer has reached to limit. Typically, the working time temperature of electronics is between 85 and 100. According to research, each 1 °C increase above the threshold temperature, chip reliability decreases by approximately 5%, accompanied by a substantial reduction in life span. Thus, if amount of heat cannot dissipate, posing a threat to chip reliability[1]. Therefore, heat sink is essential for electronic cooling heat demands. In this essay, types of heat sink and apply areas will be introduce.
How dose a heat sink work?
In thermodynamics, heat sinks control temperature by absorbing and releasing extra heat. Energy efficient heating and cooling systems is important to prevent overheating and keep devices working well. Heat sinks are used in thermal management system. Which move heat from hot components to cooling media like air or water by conduction, convection, and radiation.
Heat sink design & performance optimization
The thermal performance of pin-fin heat sinks depends on their structural design. Heat from the processor first moves to the heat sink by conduction, and then goes into the air by natural, mixed, or forced convection. Hollow base heat sinks often show better heat transfer than solid ones because they allow more air to flow inside. Fin height, hole diameter, heat input, and porosity also affect performance. When these values change, heat transfer can improve. Changes in shape can also help. Fin expansion angle and fin shapes can increase heat dissipation. Perforated fins usually transfer more heat than solid fins since they create more turbulence, but also cause a higher pressure drop. Fin arrangement is another important factor. Staggered layouts and shapes like elliptical or slotted fins often perform better than simple designs.
Types of heat sinks
Passive heat sink
Passive heat sink suit for the condition that does not reply on air flow. Which can enhance heating and cooling via a larger surface area to dissipate heat. It lower noise levels, reduce overheating risks associated with fan failure, and offer a cost-efficient cooling solutions for large components.
Active heat sink
Active heat sink usually includes mechanical components, which largely depends on the moving parts reliability. It applies for electronic control module like fan, air blowers to improve cooling efficiency. Compared with passive heat sink, owing to their smaller volume,relying on fin region.
Phase change recirculating system
Phase change recirculating systems consist of passive two-phase mechanisms involving evaporation and condensation processes. Heat pipes may be configured with or without wick structures, either relying on gravity or operating independently of it. Solid-to-liquid phase change systems fall within this category but are primarily applied for transient thermal regulation rather than steady-state heat dissipation.
Liquid cooled cold
Liquid cooled cold plates active in a liquid cooling system. They are responsible for semiconductors and ceramic printed circuit board to transfer waste heat from components. liquid cold plates demonstrate enhanced thermal performance compared to air-based cooling methods.
Heat Sink Materials
It is show that the choice of substrate material has a strong effect on the thermal shock, especially in microchannel heat sinks (MCHS). Silicon, aluminum, and graphene reveal that graphene works better because it can reduce thermal resistance. Other work on copper, aluminum, steel, and titanium remark that materials with higher thermal diffusion can improve heat transfer. This effect is stronger while the base fluid has a low Prandtl number (Pr). We also look at new designs with mixed structures. Heat sinks that use metal foam and phase change materials (PCM) can improve thermal performance. Metallic copper foams to reduce surface temperature and speed up heat absorption to make the PCM melts faster. Changes in foam structure, such as porosity and pore density. Which affecting the thermal performance. Moreover, thermal design optimization is equally important. Composite heat sinks (CHS) reveal that geometric dimensions directly affect energy storage capacity and operational duration. If the heat sink size falls below a critical threshold, the PCM is more like fully melt too quickly in long-term thermal regulation.
Ceramic substrate is available for temperature beyond 300°. Direct Bonded Copper (DBC) substrates using Al₂O₃ or AlN ceramics typically experience cracking or spalling after around 20–30 thermal cycle. The mismatch of CTE between copper and ceramic leading to ceramic crack and copper foil peeling. Using silicon nitride ceramics ceramics bonded with copper through Active Metal Brazing (AMB) technology enhance reliability. The thermal conductivity only up to half of aln. Thus, providing thinner ceramic plate is necessary.
Applications of heat sinks
In PV module, active cooling system support by mechanical and electronic devices. These equipment need extra power input. There is no need for passive cooling, but require extra components like heat sink, that depend on convective heat transfer to drive the flow of coolant to the solar cells. With the heat generation of CPU, the blow less air cooling is not sufficient. Forcing air cooling with motor-driven fans emerged and soon widely used over time[2]. In order to meet demands of light, thin requirements. We predicted that heat sink would require more aluminum heat sink fins and making use of heatpipes to ensure heat transfer. Meanwhile, reducing weight and improve product performance in the future. IGBT heat sinks based on loop thermosiphon technology offer high heat transfer fin efficiency, low thermal resistance, and uniform temperature distribution, but the performance is limited in applications involving significant motion due to gravity dependence.In this system, liquid absorbs heat from the IGBT and evaporates into vapor. The vapor then moves to a condenser, releases heat to the air, and turns back into liquid. This cycle repeats without the need for a pump, making it an energy-efficient and passive cooling method[3].
