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电动汽车驱动 ★ 4.0

高导热电绝缘电子封装用于浸没式水冷却

Thermally Conductive Electrically Insulating Electronics Packaging for Water Immersion Cooling

语言:

中文摘要

功率密度的提升使热设计成为未来电气设备研发中的关键环节。数据中心和电动汽车等系统产生的热量越来越多,这需要高效的冷却方式,以将电子设备的温度控制在其耐受极限以下,确保其可靠性。浸没式冷却已成为一种颇具前景的热管理技术,它能使冷却液更接近发热元件,从而降低热阻并提高冷却效果。尽管浸没式冷却中使用的介电流体冷却液不会影响浸没其中的电气设备的电气性能,但其冷却性能相较于水等理想冷却液而言较差。若要将水用作浸没式冷却液,电子设备需要进行封装以防止短路。在此,我们开发了一种封装方法,可使电子设备与周围的水隔离,并实现热量扩散以提高冷却效果。该封装结构包含用于绝缘和热扩散的氮化铝(AlN)组件,以及用于保形电气绝缘的聚对二甲苯 C 涂层。通过测量在高达 600 V 的直流电压下,长达 7 天时间内水中的泄漏电流,对该封装进行电气特性表征。同时,通过计算结到冷却液的热阻,对这种封装方法的热性能进行表征。所开发的封装设计可应用于热通量超出标准介电流体处理能力的高功率密度应用场景。

English Abstract

Power densification is making thermal design a key step in the development of future electrical devices. Systems such as data centers and electric vehicles are generating more heat, which requires efficient cooling to maintain the electronics at temperatures below their limits and to ensure reliability. Immersion cooling has emerged as a promising thermal management technique that brings the coolant closer to the heat-generating elements, hence reducing thermal impedance and improving cooling. Although the dielectric liquid coolants used in immersion cooling do not compromise the electrical performance of the submerged electrical devices, their cooling performance is inferior compared to ideal coolants such as water. To use water as an immersion coolant, the electronics need to be encapsulated to prevent short circuits. Here, a packaging approach is developed that insulates the electronics from the surrounding water and spreads heat for better cooling. The package consists of an aluminum nitride (AlN) component for insulation and heat spreading, and a Parylene C coating for conformal electrical insulation. The package is characterized electrically by measuring the leakage current in water under dc voltages up to 600 V for periods of up to seven days. The thermal performance of this packaging method is also characterized by calculating the junction-to-coolant thermal resistance. The developed packaging design can be implemented in high-power-density applications where the heat flux is beyond what standard dielectric fluids can handle.
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SunView 深度解读

从阳光电源的业务视角来看,这项水浸式冷却封装技术具有重要的战略价值。随着我们的光伏逆变器和储能变流器功率密度持续提升,热管理已成为制约产品性能突破的关键瓶颈。目前主流的风冷和传统液冷方案在面对350kW以上大功率设备时,散热效率和系统紧凑性难以兼顾。

该技术的核心价值在于通过氮化铝(AlN)和Parylene C涂层的复合封装,实现了电气绝缘与高效导热的统一,使水这种理想冷却介质得以应用。相比现有介电液体,水的比热容和导热系数显著更优,这意味着我们的储能系统PCS和集中式逆变器可实现更小的热阻抗和更高的功率密度。论文验证的600V耐压能力和七天稳定性测试,初步满足工业级应用要求,但距离我们1500V高压系统和20年以上寿命要求仍有差距。

技术机遇方面,该方案特别适合应用于我们正在开发的液冷储能柜和超大功率逆变器产品线。通过降低结温,可提升IGBT/SiC器件的过载能力和可靠性,这对于电网侧储能的调频调峰应用至关重要。同时,水冷系统的简化可降低维护成本,提升系统经济性。

然而,技术挑战不容忽视:AlN陶瓷的加工成本较高,Parylene镀膜的长期可靠性需要在温度循环、湿度和化学腐蚀等复合应力下进一步验证。此外,封装失效的在线监测技术、水质管理体系以及与现有产品平台的集成都需要系统性研发投入。建议将此技术纳入中长期技术预研路线图,重点关注成本优化和可靠性验证。