Aging indexes analysis of explosion-proof lithium battery based on incremental capacity method

State of health(SOH) in existing battery management system(BMS) for mine-used locomotive powered by explosion-proof lithium battery is only used to predict remaining service life of the battery, but not for cause analysis of battery aging, which has no guiding significance for battery maintenance. In order to solve the problem, internal factors leading to lithium battery aging were analyzed firstly that were lithium ion loss, dissolution of active substances and increase of internal resistance. Then an aging indexes analysis method of explosion-proof lithium battery was proposed which was based on incremental capacity(IC) method. According to height and transverse position of IC curve of lithium battery, lithium battery aging caused by lithium ion loss, dissolution of active substances and increase of internal resistance were analyzed quantitatively to obtain corresponding aging indexes. Finally, methods of calculating lithium battery IC and determining peak and valley of IC curve in BMS were introduced. The influences of charge and discharge number and charge and discharge ratio on battery aging were analyzed by battery charge and discharge tests The test results show that with increase of charge and discharge number, explosion-proof lithium battery aging is mainly caused by loss of lithium ion and dissolution of active substances when it is operated with a small charge and discharge ratio. Increasing charge and discharge ratio of the battery has the greatest influence on battery aging caused by increase of internal resistance. The method is good for BMS of explosion-proof lithium battery to estimate SOH more correctly and can provide basis for battery maintenance and BMS parameters setting.