Abstract:

At present， there is no effective method to identify and detect the micro short circuit of lithium-ion battery in the early evolution stage. Therefore， this paper proposes a micro short circuit diagnosis method based on the change law of battery charge capacity increment （IC） curve and charge capacity difference （DCC）. Firstly， the relationship between lithium battery short circuit fault and charge capacity increment is established. The IC curves are denoised by using wavelet transform， and the unique correspondence between the peak value of IC curve （ICPV） and the state of charge （SOC） of battery is obtained under different current rates and temperature. Then， DCC is proposed to be used to describe the SOC difference between the faulty battery with internal short circuit and the normal battery， and the quantitative method of lithium battery micro short circuit is obtained. Finally， simulation analysis and experiments show that the quantitative information of battery micro short circuit can be obtained under different cycling conditions， and the maximum errors of fault diagnosis are less than 8.12%.

Key words: lithium-ion battery, micro-short-circuit diagnosis, charge capacity increment（IC）, charge capacity difference （DCC）