Abstract: A device for storing electrical energy, including a plurality of switched individual cells contained inside a storage pack, a master block and a supply block supplying a DC voltage to the storage pack and the master block. In such a storage device, the storage pack is subdivided into a plurality of storage blocks, each storage block including a plurality of switched cells and a control logic sub-block for controlling each switched cell of the storage block. Each storage block furthermore also includes at least one connection sub-block for connection to a bus, each connection sub-block including an electronic switch having two positions, one position, called connected position, in which the electronic switch is open so that the storage block supplies the bus with a voltage, and one position, called short-circuit position, in which the electronic switch is closed.