Abstract: A battery pack includes a battery pack housing having a lid joined to an open end via a fluid-impermeable seal. The battery pack further includes a battery module disposed within the battery housing and comprising a plurality of electrochemical cells. In addition, the battery pack includes a pressure compensation device positioned within the battery pack housing, the pressure compensation device having a first bladder fluidly coupled to a second bladder by a primary fitting. The battery pack housing is filled with a dielectric fluid. And further, the pressure compensation device has a second fluid.

Abstract: A battery module includes a module terminal, electrochemical cells and a bus bar that electrically connects at least a subset of the cells to the module terminal. The bus bar includes an electrically conductive substrate and an insulation layer disposed between the substrates and ends of the cells. The substrate includes primary connection through holes, each primary connection through hole having a second diameter and being aligned with the first end of a unique one of the cells. The insulation layer includes secondary connection through holes. Each secondary connection through hole has a third diameter and is concentric with a corresponding one of the primary through holes. The third diameter is less than the second diameter, and an electrical connector extends between the substrate and the cell terminal and provides an electrical connection between the substrate and the cell terminal.

Abstract: A battery pack including a battery pack housing, and a battery module disposed in the battery pack housing, Tire pack housing is sealed and flooded with a dielectric fluid. The battery module includes a module housing that is fluid permeable and includes a fluid passageway, and electrochemical cells disposed in the module housing in such a way that terminals of the cells are exposed to fluid disposed in the fluid passageway. The battery pack includes a thermal management system having an inlet plenum assembly disposed at a first end of the battery module, an outlet plenum assembly disposed at a second end of the battery module, and a fluid pump that directs fluid to the inlet plenum assembly via a fluid delivery line and receives fluid from the outlet plenum assembly via a fluid return line.