Modularized charge equalizer with intelligent switch block for lithium-ion batteries in an HEV

Abstract

This paper proposes a modularized charge equalizer using intelligent voltage sensing scheme. In proposed circuit, a central equalization converter is shared by every battery cells through the cell selection switch, instead of a dedicated charge equalizer for each cell. Each cell voltage can be sequentially obtained by operating the cell selection switches. These switches are effectively used for a voltage sensing and cell selection. With this configuration, the proposed circuit can achieve the size reduction and low cost. In this digest, a prototype for eight lithium-ion battery cells is optimally designed and implemented. Experimental results verify that the proposed equalization method has excellent balancing performance showing simple operation and small size.