Patent ID: 9529056
Filing Date: 2016-12-27
CPC Classification: G01R,H01M,Y02E

Claim Text:
1. A battery system comprising: a secondary battery which has a battery voltage that is influenced more by the positive electrode potential than the negative electrode potential; a voltage sensor which detects a voltage value of the battery; a current sensor which detects a current value of the current passing through the battery; and a controller which calculates the internal resistance based on the detected voltage and current values, determines the resistance change rate based on the calculated internal resistance value, acquires a relationship between the resistance change rate and the current value detected by the current sensor when a charged state of the secondary battery is in a range lower than 50%, and determines a deterioration state of the secondary battery based on the acquired relationship, wherein the controller determines the deterioration state of the secondary battery to be deterioration due only to wear of the secondary battery when the resistance change rate is reduced as the current value is increased in accordance with a first correlation, and determines the deterioration state of the secondary battery to be deterioration due only to salt concentration distribution within the secondary battery when the resistance change rate is increased as the current value is increased in accordance with a second correlation.