BATTERY STATE DETERMINATION DEVICE

摘要

PROBLEM TO BE SOLVED: To improve determination accuracy of a battery state determination device which determines whether or not micro short circuit condition that a micro short circuit is generated is present in a battery.SOLUTION: A battery state determination device 10 is for determining presence of micro short circuit condition, which is condition in which a battery module M has a micro short circuit. The battery state determination device 10 includes: a voltage detection circuit 13 for detecting a voltage value of the battery module M; a current detection circuit 12 for detecting a current value; and a control unit 11 for detecting a state of charge of the battery module M. The control unit 11 computes a voltage gradient representing voltage variation versus a discharge amount when the state of charge of the battery module M is less than 40%, compares the voltage gradient with a preset upper limit value, and determines presence of micro short circuit condition if the voltage gradient is greater than the preset upper limit value.