Two-Phase Immersion Cooling of High-Performance Electric Traction Motors

Abstract

This article proposes an advanced approach to cooling high-performance electric traction motors by utilizing two-phase immersion cooling. The method involves immersing a stator package in a dielectric liquid, featuring higher heat transfer rates through phase change from liquid to vapor induced by heat generated by the motor components. Compared to state-of-the-art advanced cooling techniques for electric motors, the proposed two-phase immersion cooling has distinct advantages, such as higher heat transfer coefficients (HTCs) and passive cooling, eliminating the need for an external pump for immersion liquid. A motorette thermal test is carried out to measure the effectiveness of the proposed two-phase immersion cooling method on a sample stator package. The results reveal that the two-phase immersion cooling enables thermally safe operation for current density up to 40 A/mm2 by achieving superior heat transfer rates compared to state-of-the-art methods.