Real-time Battery Cell Voltage Measurement Method Using LC Series Circuit Type Cell Voltage Equalizer

Cell voltage equalizers are required in order not to be reduced the capacity of the batteries applied to electric vehicles (EVs) and other energy storage systems (ESSs). The author has proposed an LC series circuit type cell voltage equalizer which can reduce the cell voltage imbalance with higher efficiency. The proposed equalizer also can reduce the number of energy storage elements which are used in the equalizer such as inductor and capacitor. Meanwhile, not only a cell voltage equalizer but also a cell voltage monitor is essential to the batteries for their safe operation. By monitoring the cell voltage, it is possible to watch the state of ESSs and quickly detect their abnormality operation. This paper proposed a real-time battery cell voltage monitoring method using the proposed equalizer. The effectiveness of the method was verified by simulations and experiments, and the results presented that the proposed method could estimate each battery cell voltage with high accuracy.