一种串联锂离子电池组P-C-C-P均衡器及其控制方法

A P-C-C-P Equalizer and Its Control Methods for Lithium-ion Batteries in Series

针对电动汽车锂离子电池组各单体间往往存在电量不一致而导致电池组的可利用容量降低,并大大缩短了电池组使用寿命的问题,提出了一种基于反激式变压器的P-C-C-P均衡器。它结构简单、易于控制,采用反激式变压器在电池组中进行能量传输,提升了均衡效果;在电池组充、放电和静置过程中,可根据情况在3种均衡策略,即P-C、C-C和C-P中自由选择,每种均衡策略都只需对一个MOSFET进行PWM控制,能量损耗小。本文中详细介绍了均衡器的基本原理和控制方法,并搭建实验平台进行均衡实验,结果验证了该均衡器的可行性。

In view of the problem that there is often an inconsistency in capacity between single cells in a lithium-ion battery pack of electric vehicles,leading to the reduction of the available capacity of battery pack and even greatly shorten its service life,a P-C-C-P equalizer based on flyback transformer is proposed.The equalizer is simple in structure and easy to control.Flyback transformer transmits energy within battery pack,enhancing equalization efficiency.In the process of charging,discharging and stewing of battery pack,three equalization strategies,i.e.pack to cell(P-C),cell to cell(C-C)and cell to pack(C-P)can be freely selected according to the situations.Each equalization strategy only needs to carry out PWM control on one MOSFET,so the energy loss is small.In this paper,the basic principle and control method of equalizer are presented in detail,and an experimental platform is built to carry out equalization experiments.The results show that the equalizer proposed is feasible.