不同连接方式对锂电池直流内阻测试的影响

The Influence of Different Connection Modes on the Measurement of DC Internal Resistance of Lithium Batteries

内阻是评价电池性能的重要指标之一,锂电池的直流内阻通常是毫欧级别的,因此准确测量电池的直流内阻非常重要。测试受环境温度、测试时电流倍率、SOC(荷电状态)、测试设备与电池连接方式等各种因素的影响,但是测试设备与电池的连接方式对直流内阻的影响几乎没有报道。不同的连接方式测试出的结果差别非常大,因此如何正确的连接电池与测试设备对直流内阻的测试结果有至关重要影响。本文以方形磷酸铁锂电池为研究对象,分析了锂电池与测试设备之间不同的连接方式对直流内阻测试的影响。研究了测试设备电流采集线、电压采集线分别连接在锂电池极耳同侧及异侧的不同方式,结果表明:测试设备电缆线分居在电池极耳上下异侧的连接方式是最优的,在该种连接方式下,测试结果重复性好、准确性高,极大提高了锂电池直流内阻测试的可靠性。

Internal resistance is one of the important indicators to evaluate the performance of batteries.The DC internal resistance is usually at milliohms level,so it is very important to accurately measure it.The test is influenced by various factors such as ambient temperature,current rate,SOC(state of charge),and the way of the test equipment connected to the battery,but the effect of the way of the test equipment connected to the battery on the DC internal resistance has hardly been reported.The test results with different connection methods are very different,so the correct connection way is a critical impact on the test results of DC internal resistance.In this paper,taking the square lithium-iron phosphate battery as the research object,the influence of different connection modes between lithium-iron battery and the test equipment on DC internal resistance test is analyzed.we study different connection ways on the current sampling line and voltage line of test equipment respectively connected to the same side and opposite side of the pole ear of the lithium battery,the results show that the way of the connection that the cable line is separated on the different side of the the battery pole ear is optimal,under this connection way,the results are repeatable and accurate,which greatly improves the reliability of the lithium battery DC resistance test.