Patent ID: 11480627

Abstract:
Provided is a method for determining a micro short circuit of a lithium ion secondary battery which is capable of determining the presence or absence of a micro short circuit of the lithium ion secondary battery in a short time.A relaxation process after the interruption of a discharging current or a charging current is analyzed and a voltage fluctuation component due to micro short circuit is separated and used in the determination.Specifically, a method for determining a micro short circuit that determines presence or absence of the micro short circuit in a lithium ion secondary battery is provided which includes: a relaxation decomposition step of decomposing a change of a cell voltage in a relaxation process after interrupting charging current during charging or discharging current during discharging into a plurality of decomposition relaxation components; and a micro short circuit determination step of determining presence or absence of micro short circuit by determining presence or absence of a component in which a voltage drop has occurred due to the micro short circuit, among the plurality of decomposition relaxation components.