리튬이온 전지의 내압변화 원인과 안전변의 작동압 피로 시험

Abstract

Inner pressure of Li-ion battery is easily changed by temperature, battery SOC %, storage time and side reaction. Gas evolution by side reaction is main factor for inner pressure increase but the mechanism was not clearly defined. So inner pressure of Li-ion battery was directly measured during cycling and storage. Through this measurement it was found that maximum cell inner pressure came from high temperature storage by side reaction. General Li-ion battery has a vent of safety device for gas exhausting. It was predicted that vent is very weak for repeated inner pressure change because vent material is aluminum and vent is very thin. So vent fatigue test was done for operation reliability during life. The degradation of vent operation pressure by repeated inner pressure change was fount but it was not critical to vent operation.