A fast capacity estimation method for lithium-ion battery based on ICA method

Abstract

Lithium-ion batteries have attracted extensive interest for its excellent properties and high energy density, but battery ages inevitably because of long-term usage, and it is a difficult to estimate the battery capacity. This paper proposes a capacity estimation algorithm based on IC (Incremental capacity) curve for LiFePO 4 battery. The aging characteristics of the battery are analyzed by Incremental capacity analysis (ICA). Then, a battery capacity estimation model is established. The 1/20C discharge current rate is used in ICA test, and model is verified using the obtained aging characteristic parameters. In addition, the 1/3C current rate is utilized in ICA test, in order to greatly reduce the testing time. And the characteristic parameters of the IC curve are further extracted and are brought into the model for verification. The experimental results show that the proposed model can estimate battery capacity efficiently and the capacity estimation error is less than 3.5% when 1/3C is utilized in ICA method.