储能科学与技术 ›› 2020, Vol. 9 ›› Issue (5): 1497-1504.doi: 10.19799/j.cnki.2095-4239.2020.0170

• 储能材料与器件 • 上一篇    下一篇

锂离子电池极片层数对热积累效应的影响

彭文(), 杨刘倩, 朱振东   

  1. 合肥国轩高科动力能源有限公司,安徽 合肥 230012
  • 收稿日期:2020-05-08 修回日期:2020-05-20 出版日期:2020-09-05 发布日期:2020-09-08
  • 通讯作者: 彭文 E-mail:pengwen@gotion.com.cn
  • 基金资助:
    国家重点研发计划项目(2016YFB0100304)

Impact of number of electrode plate on heat accu mulation effect for lithium ion battery

Wen PENG(), Liuqian YANG, Zhendong ZHU   

  1. Hefei Gotion High-tech Power Energy Co. Ltd. , Hefei 230012, Anhui, China
  • Received:2020-05-08 Revised:2020-05-20 Online:2020-09-05 Published:2020-09-08
  • Contact: Wen PENG E-mail:pengwen@gotion.com.cn

摘要:

锂离子电池的极片为电芯最重要的组成部分,极片层数增加会提升电池的容量,但同时也造成内部的产热积累以及外部的散热受阻,最终对电池的安全性造成威胁。因此,本文以10 A·h的磷酸铁锂电池为研究对象,首先建立了一种三维分层的电化学-热耦合模型,理论分析了极片层数对热积累效应的影响,之后通过温度分布验证了本模型的精确性,最后分析了极片层数对锂离子电池温度分布的影响,以及在倍率和极片层数的综合考量下锂离子电池的热积累效应,给出了锂离子电池极片层数的设计依据。结果表明随着极片层数的增加,电池内部热积累效应增强,导致电池温度升高,并且在垂直于极片方向上存在一定的温度梯度;在高倍率以及极片层数较大时,极耳温度高于电芯温度,高温逐渐向极耳区域集中,极耳部位的散热需着重考虑;此外随着倍率的增大,电池的温差也明显增大,当倍率从3 C增大到10 C时,温差增大了约11.2倍。因此如果对电池执行快充和快放的策略,那么电池的极片层数则不宜太高,以避免电池温差过大造成内部热-电化学性质的不均匀分布,最终导致局部高温或容量衰减。

关键词: 锂离子电池, 极片层数, 热积累效应, 电化学-热耦合模型, 温度分布

Abstract:

The electrode plates of lithium-ion batteries are the most important parts of the cell. An increase in the number of electrode plate layers can increase the capacity of the battery but also causes heat generation accumulation inside the battery and blocks heat dissipation externally, which ultimately threatens the safety of the battery. In this study, a three-dimensional layered electrochemical-thermal model is proposed for a 10 A·h lithium iron phosphate battery. The influence of the number of electrode plates on the heat accumulation effect is first analyzed theoretically, and then a temperature distribution validation is conducted to ensure the accuracy of the model. Subsequently, the effect of the number of electrode plates on the temperature distribution is investigated. The discharge rate and the number of electrode plate layers are both considered to examine the heat accumulation effect of lithium ion battery. The design basis of the number of electrode plate layers is ultimately provided. The results show that the heat accumulation effect is strengthened with the increase in the number of electrode plate layers, leading to a temperature increase of the battery. In addition, there is a larger temperature gradient in the direction perpendicular to the electrode plate. With the increase in the rate and number of electrode plate layers, the temperature of the tabs becomes higher than that of the cell and the high temperature region gradually concentrates in the tabs; therefore, the dissipation of the tabs is considered. In addition, the temperature deviation also increases as the discharge rate increases; the temperature deviation increases by approximately 11.2 times when the rate increases from 3 C to 10 C. Therefore, if the strategy of fast chargingdischarge is implemented for the battery, the number of electrode plates of the battery should not be too large to avoid an uneven distribution of the internal thermo-electrochemical properties caused by the excessive temperature differences in the battery, which eventually leads to high local temperatures or capacity degradation.

Key words: lithium ion battery, number of electrode plate, heat accumulation effect, electrochemical-thermal model, temperature distribution

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