Study on the health status of lithium-ion batteries based on relaxation voltage characteristics

Over-discharge of lithium-ion batteries can seriously affect the performance and service life of lithium batteries. In order to characterize the aging degree of Li-ion batteries under the consideration of over-discharge, this paper proposes a method for extracting the health status factor of Li-ion batteries based on the voltage drop characteristics during the relaxation period. Firstly, the experimental platform of Li-ion battery over-discharge is set up to obtain the data of Li-ion battery over-discharge; Secondly, the induction mechanism of Li-ion battery internal short-circuit induced by over-discharge is theoretically analyzed; Lastly, the characteristic quantity of voltage drop during the relaxation period of the Li-ion battery is extracted after it is fully charged to obtain the characterization of the battery health status factor, and the degree of aging is classified through the method of clustering. The results show that the proposed battery health status factor can better characterize the aging degree of lithium battery.