Battery Pack with a Pressure Management System including a Compensating Device

A battery pack includes a battery pack housing that is flooded with a dielectric fluid and sealed. The battery pack includes a vent block disposed on an outer surface of the housing, and a bladder disposed inside the housing that communicates with the vent block via a fitting. The bladder interior space includes air, and the bladder expands and contracts to accommodate volume changes of the dielectric fluid due to changes in the environment of the battery pack.