Patent attributes
A battery pack system is disclosed. The battery pack system includes a plurality of battery pack modules that are each configured to be concurrently and removably attached to a base. Each battery pack module includes batteries arranged in a plurality of parallel groups that are connected in series. Each parallel group includes a plurality of batteries connected in parallel. Additionally or alternately, the base has electronics that connect the battery pack modules in a plurality of system parallel groups that are connected in series. Each system parallel group includes a plurality of battery pack modules connected in parallel.