Design of SOC evaluation unit for multi-cell traction battery system

This paper deals with the design procedure of the system which consists of measuring part and evaluation part for multi-cell of lead-acid traction batteries. The main task of this system is an online state of charge (SOC) estimation. For identification parameters of the battery equivalent circuit, the measuring procedure was realized, which is needed for the design of an accurate measuring circuit. Accuracy of measuring circuits is very important because the state of charge estimation is based on results from the measuring circuit. In evaluation part of the system is implemented open-circuit voltage method and coulomb counting method. The functionality of the proposed system was tested and verified in the real application.