不同老化状态三元锂离子动力电池热特性

Thermal characteristics of NCM lithium-ion power batteries under different aging states

为认知电池在老化过程中的产热特性,研究了不同健康状态的18650型三元锂离子电池多个测试条件下的电池产热过程和温升情况,分析了各状态下不同放电深度(DOD)时电池直流内阻和熵变系数,计算了电池可逆与不可逆产热功率,总结了不同老化状态电池放电产热中热量构成。结果表明放电过程中产生的热量主要是不可逆热量。随电池老化程度增加,不可逆产热量增大。各状态下可逆产热均在50%DOD时达到最大。随着老化程度加深,直流内阻增加,大倍率放电时产热增加明显,低温放电性能变差。

In order to understand the thermal behavior of the battery during the aging process,the battery heat generation and temperature rise of the 18650 NCM battery in different health states were investigated under several test conditions.The DC internal resistance and entropy change coefficient of the battery were analyzed.And the reversible and irreversible heat generation power of the battery were calculated.The heat composition in the discharge heat generation of the battery in different aging states was summarized.The results show the irreversible heat is dominant in the process of discharge.As the aging degree of the battery increases,the irreversible heat increases.The reversible heat production in each state reaches the maximum at 50%DOD.DC internal resistance and the heat generation increase significantly with the ongoing of the aging process,and the low-temperature discharge performance deteriorates.