Equalization method and equalization system for lithium ion battery pack

The present invention discloses an equalization method and an equalization system for a lithium ion battery pack. The equalization method comprises the steps of: performing equalization for states of adjacent single-battery units in the lithium ion battery pack and acquiring voltage information of the single-battery unit by a first-stage equalization module; performing equalization for states of adjacent two-battery units by a second-stage equalization module; performing equalization for states of adjacent four-battery units by a third-stage equalization module; and obtaining the voltage information and generating an equalization control instruction by a processor, so as to control the first-stage equalization module, the second-stage equalization module and the third-stage equalization module to perform corresponding state equalization operation. According to the above technical scheme, the equalization system consisting of the first-stage equalization module, the second-stage equalization module, the third-stage equalization module and the processor is simple in structure and low in cost, and equalization mechanism of the whole equalization system can be conveniently and quickly changed through modification of an equalization algorithm in the processor, thereby achieving the purpose of simply and conveniently controlling work states of the equalization modules.