Active Equalization of Lithium-Ion Battery Based on Reconfigurable Topology

Abstract

The equalization technique is a key technique in the secondary utilization of retired batteries. In this paper, a double-layer equalization method is proposed, which combines the reconfigurable topology with the converter active equalization method. The inner layer uses the reconfigurable topology to have a balanced set of battery cells. Thanks to isolating the lowest SOC (state of charge) cell in the battery group, the energy transfer loss among cells is avoided. In addition, this topology can reduce cost and control complexity and the number of components. In the outer layer, a Buck–Boost converter is added for each battery group, and the outputs of the converters are connected in series. The output voltage of the converter varies as the SOC of the group varies while the total output voltage is stable. In order to validate the proposed method, an equalization circuit consisting of 12 battery cells is built on Matlab/Simulink. Simulation results show that the proposed method can effectively balance the battery pack and maintain a stable output voltage. Compared to the conventional active equalization method, the proposed method has significantly improved the equalization efficiency.

Simulation and Testing of Self-Reconfigurable Battery Advanced Functions for Automotive Application

“…As shown in many articles [1], battery-switching technologies of Self-Reconfigurable Batteries (SRBs) promise significant improvements in terms of autonomy and battery life, cell balancing [2][3][4][5][6][7], recharging capacity [8][9][10][11], improving the efficiency of vehicle drive trains [12][13][14] and even cell aging [15][16][17]. Their operating principle is as follows: switches are added to the power paths linking the cells to enable the number of active stages in series and parallel to be modulated dynamically [18], depending on the type of SRB.…”

Research on reconfigurable topology layered equalization method based on maximum capacity utilization

“…By changing the charging and discharging time of the battery cells, the equalization efficiency is improved by reducing the unnecessary charge transfer. Literature [ 9 ] presents the problem of adding DC-DC converters within each battery pack thus stabilizing the battery pack but increasing the cost and control difficulty. Literature [ 10 ] simplifies the voltage stabilization scheme by adding a redundant unit within each battery pack to be activated alternately in time to achieve this goal.…”

Battery Cell Balancing of V2G-Equipped Microgrid in the Presence of Energy Storage Aggregator

“…Tis method can be used only for low-voltage applications, and it afects the battery life. A cell bypass active balancing method is introduced in [12]. Te method is very cheap and very easy to control.…”