To suppress the occurrence of system shutdown after long term storage of batteries. A semiconductor device comprises a control unit that controls charging and discharging of a battery cell, and a ROM that stores a power supply capability value which specifies a power supply capacity of the battery cell that can be stably supplied to an application system in which the battery pack is provided. After the battery pack returns from the sleep mode and before the transmission request of the power supply capability value is received from the system, the control [unit performs a power supply capability value updating process of updating the power supply capability value in the ROM to a value smaller than the power supply capability value before the sleep mode.