Thermal management of automotive SiC-based on-board inverter with 500 W/cm<sup>2</sup> in heat flux, and Two-phase immersion cooling by breathing phenomenon spontaneously induced by lotus porous copper jointed onto a grooved heat transfer surface

In this study, we quantitatively discuss several kinds of thermal resistances that rise up to the surface in thermal management of automotive SiC-based on-board inverters with extremely high heat flux of 500 W/cm2. It is proven that a stacking structure without a heat spreader and a direct cooling method utilizing two-phase immersion cooling technique can provide a breakthrough as the key technology. Furthermore, it is verified that a two-phase immersion cooling technique using "breathing phenomenon" spontaneously induced by a lotus copper jointed onto a grooved heat transfer surface can realize both the above-mentioned stacking structure and extremely high critical heat flux beyond 500 W/cm2 in a saturated pool boiling environment (534 W/cm2 at the maximum).