Abstract:
As a kind of high-temperature batteries, the operating temperature of liquid metal batteries (LMBs) is between 300℃~700℃, which has an important influence on battery performances. This paper explored the effect of operating temperature on the open circuit voltage (OCV), charge and discharge performances and the internal resistance of LMBs. Firstly, a dual polarization equivalent circuit model was built. The OCVs at different operating temperatures were obtained by the resting method, and the relevant electrochemical-thermodynamic parameters were calculated by the Gibbs-Helmholtz equation and the Nernst equation. The cycle performances at different operating temperatures were investigated through battery cycle tests. The pulse test data were used to identify the internal resistance at different operating temperatures, and the effect of operating temperature and state-of-charge (SoC) on the internal resistance was analyzed from the aspects of reaction interface evolution, electrode reaction and mass transfer process. The simulation results show that the improved dual polarization model error is within ±0.03V, indicating that the model could accurately reflect the dynamic characteristics of LMBs.