English
usheenthermal
alibaba
In the global pursuit of green energy savings and intelligent living experiences, air conditioners, as core devices for regulating indoor comfort, are increasingly scrutinized for their energy efficiency and reliability. Within the complex and precise systems of an air conditioner, beyond the primary refrigeration cycle components, a series of seemingly inconspicuous thermal products—such as various thermal interface materials and electronic heat sinks—silently play a crucial role in ensuring their efficient and stable operation, especially in addressing the growing challenges of electronic integration and power density.
Within the "brain" of the air conditioner—the electronic control modules and power devices—the application of thermal products is particularly critical and diverse. Modern air conditioners, especially inverter-driven and smart models, are packed with sophisticated printed circuit boards (PCBs). These boards house microprocessors, power transistors (like IGBT modules), driver ICs, and various sensors. During operation, these components generate significant Joule heat. If not dissipated effectively and promptly, this heat can lead to performance degradation, operational instability, or even permanent damage due to overheating, directly impacting the air conditioner's lifespan and user experience.
To effectively dissipate the heat generated by these densely integrated electronic components, heat sinks are commonly employed. These are typically made from aluminum alloys formed by extrusion or die-casting, chosen for their excellent thermal conductivity. These heat sinks are designed with numerous fins to significantly increase the surface area contact with the air, thereby accelerating heat dissipation into the surrounding environment. They are either directly or indirectly in close contact with the heat-generating core components.
However, relying solely on heat sinks is insufficient. The microscopic irregularities on the surfaces of heat-generating components and the heat sink base create air gaps. Since air is a poor conductor of heat, these gaps result in substantial contact thermal resistance, severely impeding heat transfer. This is where a wide array of Thermal Interface Materials (TIMs) comes into play. Their primary mission is to fill these gaps, displace the air, and establish an efficient heat transfer pathway.
For instance, thermal grease is one of the most common TIMs. It is a paste-like substance with good wetting properties and low initial thermal resistance, capable of effectively filling minute gaps to ensure intimate contact between the heat-generating chip and the heat sink. Its thermal conductivity typically ranges from 1-8 W/m·K, striking a good balance between cost and performance, making it widely used for cooling CPUs, GPUs, and power modules. Requirements for thermal grease include good thermal conductivity, stable physical and chemical properties across the operating temperature range, non-drying, non-bleeding, and a degree of electrical insulation.
For applications requiring the filling of larger gaps, uneven surfaces, or a combination of cushioning, shock absorption, and electrical insulation, thermal pads are selected. These are solid, possessing a degree of elasticity and thickness. Typically made from a silicone rubber matrix filled with thermally conductive fillers (such as alumina or aluminum nitride ceramic powders), they offer good compressibility, resilience, and surface conformity. Their thermal conductivity covers a broader spectrum, from 1 W/m·K to over 15 W/m·K for high-performance products, effectively addressing varying power densities and assembly tolerances. Beyond thermal conductivity, they must also provide excellent electrical insulation (often requiring a high dielectric breakdown voltage), aging resistance, and long-term reliability.
Furthermore, there are more advanced or application-specific thermal products. Thermal gels combine the flowability of grease with some of the form stability of pads, allowing for automated dispensing and better adaptation to complex surfaces, resulting in superior gap filling. Phase Change Materials (PCMs) transition from a solid to a semi-liquid state at a specific phase change temperature, allowing them to better wet the interface and offer extremely low interface thermal resistance, particularly suitable for applications with stringent thermal resistance requirements. Graphite sheets, with their exceptionally high in-plane thermal conductivity (reaching 1500 W/m·K or even higher), can efficiently spread point heat sources into planar heat sources, equalizing temperature distribution. They are often used in space-constrained applications requiring rapid heat spreading, such as in the display panels or communication modules of smart air conditioners.
The specific requirements for these TIMs are very stringent: firstly, they must possess high thermal conductivity and low thermal resistance to ensure heat transfer efficiency; secondly, they need good interface wetting and filling capabilities to thoroughly displace air; thirdly, for most applications, electrical insulation is essential to prevent short circuits; finally, long-term operational reliability, such as resistance to high and low temperatures, anti-aging properties, non-drying, non-bleeding, and compliance with environmental directives like RoHS, are fundamental prerequisites.
Considering current industry trends, the rapid increase in the intelligence and integration levels of air conditioner products—for example, with embedded Wi-Fi modules, AI voice control chips, and more complex inverter drive control units—means the power density of these components continues to rise. This, in turn, escalates the demand for higher-performance thermal products. The penetration of 5G and IoT technologies in the smart home sector further complicates the internal electronic systems of air conditioners, making their stable operation highly dependent on efficient thermal management solutions. This drives the research and application of novel thermal materials with higher thermal conductivity, thinner profiles, and superior overall performance. For instance, in some high-end models, thermal solutions for high-power devices like IGBT modules might employ ceramic substrates with superior thermal conductivity (such as aluminum nitride) combined with high-performance thermal gels or PCMs to tackle the increasingly severe heat dissipation challenges. These "unseen" thermal products are working behind the scenes to ensure our air conditioners operate efficiently and reliably during scorching summers or frigid winters, contributing indispensably to achieving higher energy efficiency standards and longer product lifespans.
