Patent attributes
An electricity storage system includes an electricity storage block including an electricity storage element for performing charging and discharging; a relay switched between an ON state in which the electric storage block is connected to a load and an OFF state in which a connection between the electricity storage block and the load is cut off; a controller for controlling the ON state and the OFF state of the relay; and a current cutoff circuit so as to cut off energization of the electricity storage block. The current cutoff circuit has an alarm circuit to indicate that the electricity storage block is in an overcharged state by comparing a voltage value of the electricity storage block and a threshold; a latch circuit retains the alarm signal; and a transistor receives an output signal of the latch circuit and switches the relay from the ON state to the OFF state.