A Study on Battery Management System of Ni-MU Bat ery Packs for Hybrid Electric Vehicle Applications

This paper proposes a decentralized battery management system (BMS) of nickel metal hydride (Ni-MH) battery packs for hybrid electric vehicle (HEV) applications, which is necessary and important to guarantee the Ni-MH battery pack's performance in the HEV application. The presented BMS, which consists of a central management unit and data acquisition modules, features the characteristics of reduced wiring, great ability of expansion, easy installation, and high precision and reliability. The estimation algorithm of the state of charge (SOC) of the battery pack combines the open circuit voltage method and the coulometer method in order to obtain high precision.

I. Introduction

In a world where more and more countries become aware of the need for environment protection and energy conservation, the development of electric vehicles (EVs) and hybrid electric vehicles (HEVs) has taken an accelerated pace. EVs and HEVs are gradually available in the market, which makes the dream of having commercially viable EVs and HEVs into a reality [1].