US Patent 11539222 Battery control unit and battery system

A switching unit is provided for each of a plurality of batteries arranged in series, and switches between a connected state where the corresponding battery is connected in series with another battery and a non-connected state where series connection between the corresponding battery and the other battery is disconnected. A control unit controls the switching unit corresponding to the battery to switch to the non-connected state when it is determined that the corresponding battery reaches a charge end voltage during charging or a discharge end voltage during discharging, and determinates deterioration of the batteries. Further, the control unit changes the charge end voltage or the discharge end voltage for each of the plurality of batteries in accordance with a deterioration state of the plurality of batteries.