Cold Plates

Effective liquid cooling is a major challenge for battery makers. Cold plates between the modules are the easiest to fabricate but they are bulky and do not make good thermal contact with the cells. Serpentine systems such as those found in Tesla modules have channels that weave around the cells; Although they are adequate for their very large packs and are often used in passenger cars where mileage is the top priority, they add to the overall dimensions of the pack and leave the cells vulnerable with a crash. Immersion systems have the cells in direct contact with the liquid. Although this is very effective for heat transfer, it also requires extra space and leaves the cells vulnerable, as well as adding a lot of complexity to the system as the fluid must be electrically insulative, thermally conductive, and easy to pump.

EV Drive modules use an integrated aluminum cold plate that takes the place of one of the two cover plates, only adding 2mm of thickness to the overall module dimensions. The plate has a minimal gap between the terminal end of the cells where the heat accumulates. The module itself is filled with an electrically resistive, thermally conductive encapsulant which conducts heat from all parts of the module to the cold plate. The solid, fire-resistant encapsulant creates a solid brick with the cells electrically and physically isolated but as close together as possible. This results in a very compact, well cooled, extremely robust module.