Effect of Internal Resistance on Consistency in a set of Batteries at Low Temperature

An electric vehicle needs to use multiple individual batteries in a set to meet the requirements for use. This then imposes very strict requirement for the consistency in performance among individual batteries. This article has studied the internal resistance on the consistency in a set of batteries at low temperatures. The result indicates, the inconsistency of internal resistance among individual batteries connected in series in a set will hinder the performance of the batteries set. During the process of recharge, because of the difference in internal resistance, the recharge voltages applied to individual batteries in serial connection are different, resulting in the inconsistency in recharge voltage among batteries. And as the process of recharge goes on, the voltage of the battery with higher internal resistance may reach the upper limit on recharge voltage early. As far as the batteries in parallel connection in a set is concerned, because of the difference in internal resistance, the recharge currents distributed among individual batteries are different, with the voltages of the batteries at higher recharge currents to rise fast.