Research on Sensorless Equalization Current Estimation of Liquid Metal Battery

Liquid metal batteries (LMBs) are promising for a wide range of applications. However, due to the low voltage of individual batteries, they need to be connected in series for use in large groups. Thus, balancing of the battery pack is required. The effect of the equalizing current is often ignored when using SoC as the equalization criterion in traditional study, but the high equalizing current for LMBs is not negligible. However, the acquisition of the equalizing current is costly and difficult to implement. To solve this problem, this paper investigates a sensorless equalizing current estimation method for LMB equalization circuits. By building a simulation model of the battery and the equalization circuit, analyzing the equalization circuit characteristics and using the simulation findings to fit the parameters, an equation for the estimation of the equalization current is given. The results show that the average error of the equalizing current estimation is less than 3%.