基于容量增量法的防爆锂电池老化指标分析

Aging indexes analysis of explosion-proof lithium battery based on incremental capacity method

  • 摘要: 现有防爆锂电池矿用机车电池管理系统中电池健康状态仅用于预测电池剩余使用寿命,不对电池老化原因进行分析,对电池维护缺乏指导意义。针对该问题,首先分析了导致锂电池老化的内部因素,即锂离子损耗、活性物质溶解、内阻增加;然后基于容量增量法原理,提出了一种防爆锂电池老化指标分析方法,根据锂电池容量增量曲线高度和横向位置分别对锂离子损耗、活性物质溶解、内阻增加导致的锂电池老化进行量化分析,得出了相应的老化指标;最后介绍了电池管理系统中计算锂电池容量增量和确定容量增量曲线峰谷点的方法。采用电池充放电试验分析了充放电次数和充放电倍率对电池老化的影响:防爆锂电池以较小充放电倍率操作时,随着充放电次数增加,锂电池老化主要为锂离子损耗和活性物质溶解导致的老化;增大电池充放电倍率对内阻增加导致的电池老化影响最大。该方法有助于防爆锂电池管理系统更准确地估算电池健康状态,并为电池维护和电池管理系统的参数设定提供依据。

     

    Abstract: State of health(SOH) in existing battery management system(BMS) for mine-used locomotive powered by explosion-proof lithium battery is only used to predict remaining service life of the battery, but not for cause analysis of battery aging, which has no guiding significance for battery maintenance. In order to solve the problem, internal factors leading to lithium battery aging were analyzed firstly that were lithium ion loss, dissolution of active substances and increase of internal resistance. Then an aging indexes analysis method of explosion-proof lithium battery was proposed which was based on incremental capacity(IC) method. According to height and transverse position of IC curve of lithium battery, lithium battery aging caused by lithium ion loss, dissolution of active substances and increase of internal resistance were analyzed quantitatively to obtain corresponding aging indexes. Finally, methods of calculating lithium battery IC and determining peak and valley of IC curve in BMS were introduced. The influences of charge and discharge number and charge and discharge ratio on battery aging were analyzed by battery charge and discharge tests The test results show that with increase of charge and discharge number, explosion-proof lithium battery aging is mainly caused by loss of lithium ion and dissolution of active substances when it is operated with a small charge and discharge ratio. Increasing charge and discharge ratio of the battery has the greatest influence on battery aging caused by increase of internal resistance. The method is good for BMS of explosion-proof lithium battery to estimate SOH more correctly and can provide basis for battery maintenance and BMS parameters setting.

     

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