Vapor Chamber Acting as a Heat Spreader for Power Module Cooling

This paper presents an integrated power electronics module with a vapor chamber (VC) acting as a heat spreader to transfer the heat from the insulated gate bipolar transistor (IGBT) module to the base of the heat-sink. The novel VC integrated in a power module instead of a metal substrate is proposed. Compared with a conventional metal heat spreader, the VC significantly diffuses the concentrated heat source to a larger condensing area. The experimental results indicate that the VC based heat-sink will maintain the IGBT junction temperature $20°C$ cooler than a non-VC based heat-sink with high power density. The junction-to-case thermal resistance of the power module based on the VC is about 50% less than that of the power module based on a copper substrate with the same weight. The chip overshooting temperature of the copper substrate module with the same weight goes beyond $10°C$ against the junction temperature of the VC module at a given impulse power of 225 W. Consequently, thanks to a longer time duration to reach the same temperature, a power surge for the chip can be avoided and the ability to resist thermal impact during the VC module startup can be improved as well. The investigation shows that the VC power module is an excellent candidate for the original metal substrate, especially for an integrated power module with high power density.