Thermal Management System (TMS) for EVs is a new technological field and is in search of evolution in various fields.

The shift to xEVs increases the number of heat-generating components compared to internal combustion engine vehicles, makes thermal management systems more complex, and includes a wide range of heat-generating scenarios. Therefore, development based on actual equipment requires an enormous amount of time when trying to comprehensively verify these factors. Traditionally, power semiconductors using Si materials have been the mainstream, and loss reduction has been promoted by devising device structures. In recent years, devices made of wide bandgap materials such as SiC and GaN have emerged, leading to further loss reduction. The development trend toward lower loss in power semiconductors is a matter of concern.

The three subsystems targeted are the powertrain cooling system (PCS), which includes motors and inverters that need to be cooled; the battery thermal management system (BTMS), which requires cooling and heating; and the air conditioning system (ACS). The key is the integrated architecture of this TMS. The main issues are to improve power consumption efficiency and cost, and to respond to the environment and EV evolution. Among the many exhibits in semiconductor heat dissipation-related topics and eAxle-related thermal management, one that was featured quite prominently was the “automotive battery thermal management field.

The scale of damage caused by the BEV fires is so large that the loss of trust and image of the OEMs and suppliers involved is immeasurable, and it takes a lot of effort and time to regain trust once it is lost. It will take considerable effort and time to regain that trust once it is lost. For these reasons, the trend toward cost reduction that has been emphasized in the automotive industry in the past is shifting toward safety. In this context, moves toward more effective battery thermal management have been in full swing since the end of last year.

First, there have been a number of moves to propose super engineering plastics and silicon/silica materials for intercell materials and temperature control-related applications. High-performance resin materials and silica materials that can withstand temperatures up to around 1,200°C are attracting attention amid the demand for heat resistance that can withstand temperatures of approximately 1,000°C during thermal runaway. In particular, new concepts such as the use of ceramics as intercellular material were proposed this year, and proposals for a variety of concept technologies in thermal management were fresh.

In addition, there was a proposal for a technology called “Immersion Cooling,” which has been proposed in Europe, Taiwan, and other countries since the end of 2023, in which the cells are constantly immersed in cooling oil to maintain a constant temperature. (Immersion Cooling has already been commercialized for server cooling in some IT industries). Although various challenges have been pointed out for its practical application in automobiles, it has been proposed by global lubricant suppliers TotalEnergies and Castrol, as well as Valeo, Xing Mobility, and others.