48 V MHEV NMC 배터리 전류-전압 예측을 위한 임피던스 기반 등가 회로 모델 개발

Abstract

A battery management system(BMS) is responsible for the safe operation of a lithium-ion battery pack in a mild hybrid electric vehicle(MHEV). One of the main functions of BMS is to supply the vehicle with the required power. However, the available battery power is entirely dependent on the impedance characteristic of the battery that is affected by temperature, current, and state of charge(SOC). In this study, a battery pack model of the 48 V MHEV battery is developed in order to simulate the response of the battery under vehicle driving conditions. The model is developed based on hybrid pulse power characterization(HPPC) and electrochemical impedance spectroscopy(EIS) experiments over temperatures ranging from -20 oC to 25 oC. The current dependency of charge transfer resistance is considered in the battery model by including the Butler-Volmer equation. The 48 V battery pack model for the MHEV is developed based on the cell model, and it is used to validate the results of the MHEV tests.