Energy storage battery automatic balancing

A SOC balancing control strategy for energy storage units with a voltage balance function is proposed. An analysis of SOC trends is carried out in response to the power changing of loads and micro-source. An adaptive virtual resistances algorithm is coordinated with the control strategy of VB to accelerate the balance process.

Active balancing has emerged to overcome the drawbacks of passive cell balancing, where it utilizes capacitors, transformer, converters, and inductors to transport energy among the cells within a BESS without employing shunt resistors. Energy is moved among the cells based on their energy, from higher energy to lower energy.

The experiment results demonstrate that compared with the balancing process with a static acceleration coefficient, the proposed adaptive balancing control of cell voltage shows significant improvement in balancing speed and smaller cell voltage discrepancy.

However, this causes dissipation of additional energy (Huang and Qahouq, 2015), and because low bypass currents are used, equalization times are very long. Active cell balancing methods remove charge from higher energy cells and deliver it to lower energy cells through active cell equalizing circuits.

Cell balancing is a way to compensate for weaker cells by equalizing the charge on all the cells in the chain, thus extending battery life.

Abstract The performance of a battery energy storage system is highly affected by cell imbalance. Capacity degradation of an individual cell which leads to non-utilization for the available capacity of a BESS is the main drawback of cell imbal-ance.