Nonuniform current distribution within parallel-connected batteries

yanhui Zhang1, Jiyong Zheng#, Shili Lin, Fanfei Bai, Waqas Hassan Tanveer, Suk Won Cha, Xinyu Wu#, Wei Feng#

An imbalanced current distribution is often observed in cables of parallel batteries, which may limit the release of the energy and power in the battery pack. Hence, it is very important to analyze the homogeneous current distributions within parallel battery batteries and explore the effect on the state of charge and energy loss. Initially, it can be found that a battery near the load will experience a large local current under higher discharge rate. With the discharge, the current distribution will show a surge wave distribution, and the peak is gradually shifted backwards. As discharge continues, local current profile in segments will have different development trends, while current profile with lower initial current values increase, which leads to an entirely different form of current distribution with the initial stage of discharge. The current profile moves in a wavelike form transmission when the total discharge rate is low. The higher the current rate, the more divergent the current distribution. The state of charge distribution is also nonuniform, clearly indicating underutilization of active materials, which will further aggravate the nonuniformity of the local current distribution in the parallel battery pack.