A cell control unit (20) individually controls cell capacities (SOC) of a first subset (Cf) of a set of cells (Cj) in a heat dissipating manner by using discharge resistors (Rj), a set of estimation elements (21, 31-33, S1-S6, S11-S16, S18-S19) estimates a degree of heat dissipation of the set of cells (Cj) in terms of a temperature rise (To(n)-To(0)) of a substrate (25) of the cell control unit (20), and a set of interruption elements (SWj, S17) interrupts controlling cell capacities (SOC) of a second subset (Cs) of the first subset of cells (Cf) determined in dependence on the estimated temperature rise (To(n)-To(0)).