A battery pack typically includes multiple rechargeable battery cells. High-voltage battery packs, such as those used to power a torque-generating electric machine, can generate substantial amounts of heat during sustained operation. As a result, a battery thermal management system is typically used to regulate battery cell temperature. For instance, coolant may be circulated in a closed-loop channel located near the battery cells. Thin thermal plates referred to as cooling fins may be used to help direct circulated coolant between adjacent battery cells to facilitate cooling.
In some battery cells, an insulating separator material may be arranged between oppositely-charged electrodes and enclosed within a sealed outer pouch filled with an electrolyte solution. The separator material, e.g., polyethylene and/or polypropylene film, helps prevent an electrical short condition while permitting the free transfer of electrical charge between electrodes. Positive and negative cell tabs of the battery cell, which are electrically connected to the respective electrodes, extend a short distance outside of the sealed pouch to form electrode terminals for the battery cell. The electrode terminals of multiple battery cells are typically ultrasonically welded together via a conductive interconnecting member positioned outside of the battery cells in order to form the battery pack.