锂离子电池熵热系数间接计算方法

Indirect calculation method of entropy heat coefficient of lithium-ion battery

为了解决直接测量熵热系数存在实验周期长,以及轻微自放电对测试结果准确性的影响,提出了一种间接测量熵热系数的方法。通过实验测得不同温度下电池的内阻,计算得到1 C放电倍率下的内阻生热率。分别在绝热和室温条件下测得电池1 C放电倍率下的温升,计算得到总生热率,结合1 C放电倍率下的内阻生热率,基于Bernardi生热速率模型公式,间接计算得到电池的熵热系数。结果表明:在2种条件下得到的熵热系数曲线变化趋势基本一致。可见,可以采用此种方法来计算电池的熵热系数。

In order to solve the problem of direct measurement of the entropy heat coefficient of lithium-ion batteries,there were long test cycles and slight self-discharge,and the effect of slight self-discharge on the accuracy of test results,an indirect method for measuring the entropy-heat coefficient of lithium-ion batteries was proposed.The internal resistance of the battery at different temperatures was measured experimentally,and the internal resistance heat rate at 1 C discharge rate was calculated.The temperature rise under the 1 C discharge ratio of the battery was measured at the condition of adiabatic and room temperature.The total heat rate was calculated and the internal resistance heat generation rate under the 1 C discharge ratio was calculated.The entropy thermal coefficient of the battery was calculated indirectly based on the formula of the Bernardi heat generation rate model. The results showed that the curves of entropy heat coefficient were in good agreement under the two conditions.It can be seen that this method can be used to calculate the entropy heat coefficient of the battery.