Patent attributes
In an electrical instrument to which a plurality of battery blocks and/or a plurality of batteries are detachably connectable, to prevent a phenomenon that only specific battery and battery block are deteriorated. A hybrid battery connectable to a body of an electrical instrument consuming electrical power includes: a cell block which includes one or more battery cells, and supplies electrical power to the body of the electrical instrument by discharging after being charged; and a cell block which includes one or more battery cells, supplies electrical power to the body of the electrical instrument by discharging after being charged, and becomes active selectively with the former cell block. In the hybrid battery, a CPU selects a cell block becoming active based on the number of charge/discharge cycles of the former cell block and the number of charge/discharge cycles of the latter cell block.