Abstract: Operating electric power is preferably supplied to a battery assembly control circuit from both a power converting device and a battery module. An electricity storage device includes a battery module including battery cells and a battery assembly control circuit, and a power converting device configured to charge the battery module with a commercial power supply and to supply electric power to a load. The power converting device supplies electric power to the battery assembly control circuit while an output voltage of the power converting device is higher than a predetermined voltage. The battery module starts to supply operating electric power to the battery assembly control circuit upon detecting that the electric power from the power converting device starts to be supplied to the battery assembly control circuit. The battery module stops supplying the electric power to the battery assembly control circuit when the battery module stops being discharged.

Abstract: A power supply device includes a spike absorption circuit that suppresses an avalanche breakage of a current shutdown switch due to a kickback voltage that may appear in response to the cut-off of a load current. The current shutdown switch is connected to secondary batteries. The spike absorption circuit is a series circuit of a protection switch, formed of a semiconductor element, and a diode. The power supply device further includes: a small-signal switch that controls turn-on and turn-off of the protection switch; and a delay circuit that maintains the small-signal switch in an ON state over a setup time after a current shutdown timing of the current shutdown switch. The delay circuit maintains the small-signal switch in the ON state over the setup time (T), and the small-signal switch thereby causes the protection switch to the ON state. Then, the spike absorption circuit damps the kickback voltage.

Abstract: A power supply device includes a spike absorption circuit that suppresses an avalanche breakage of a current shutdown switch due to a kickback voltage that may appear in response to the cut-off of a load current. The current shutdown switch is connected to secondary batteries. The spike absorption circuit is a series circuit of a protection switch, formed of a semiconductor element, and a diode. The power supply device further includes: a small-signal switch that controls turn-on and turn-off of the protection switch; and a delay circuit that maintains the small-signal switch in an ON state over a setup time after a current shutdown timing of the current shutdown switch. The delay circuit maintains the small-signal switch in the ON state over the setup time (T), and the small-signal switch thereby causes the protection switch to the ON state. Then, the spike absorption circuit damps the kickback voltage.