锂离子电池SOC及容量的多尺度联合估计

The State of Charge (SOC) and battery capacity estimation of lithium-ion battery are the core of battery management system. Because the parameters of SOC and capacity affect each other in the estimation process, a multi-scale joint estimation method for SOC and capacity of ternary lithium-ion battery is proposed. In this paper, we use the equivalent circuit model of Thevenin to establish the mathematical model and state space equation. In order to solve the problem of different characteristics of battery at different temperatures, model parameters identification was carried out at different temperatures, and the two-dimensional pulse spectrograms of parameters related to SOC and temperature were established. Based on the Dual Extended Kalman Filter (DEKF), a multi-scale joint estimation model of battery state is established. The SOC and polarization voltage of the battery are estimated on the micro-time scale, the capacity of the battery is estimated on the macro-time scale, and the capacity of the SOC estimation is updated to ensure the accuracy of battery long-term estimation. Finally, the proposed multi-scale joint estimation algorithm for ternary lithium-ion battery is validated in a wide temperature range, and the result shows that it has high accuracy.