SCALABLE BATTERY SYSTEM

A battery module contains a casing, a cell frame received within and connected to the casing, a first connector mounted to the cell frame; a second connector mounted to the cell frame; and a plurality of sub-modules installed in the cell frame. Each of the plurality of sub-modules includes a plurality of battery cells. Each of the plurality of sub-modules further contains a positive output terminal and a negative output terminal that are connected to the first connector or the second connector. A plurality of interconnecting features allows the battery module to detachably connect to an adjacent battery module of a same type to form a scalable battery system. Similar battery modules can be stacked to form a battery system with additional capacity, without the need to modify the internal structure or circuit connection of the individual battery module.