储能科学与技术 ›› 2024, Vol. 13 ›› Issue (7): 2171-2180.doi: 10.19799/j.cnki.2095-4239.2024.0374

• 低温电池专刊 • 上一篇    下一篇

调控电解液溶剂组分实现LCO/C低温18650电池循环寿命显著提升

程广玉1(), 刘新伟2, 刘硕1, 顾海涛1, 王可1   

  1. 1.空间电源全国重点实验室,上海空间电源研究所,上海 200245
    2.上海航天电源技术有限;责任公司,上海 201112
  • 收稿日期:2024-05-06 修回日期:2024-05-31 出版日期:2024-07-28 发布日期:2024-07-23
  • 通讯作者: 程广玉 E-mail:chengguangyu12@126.com
  • 作者简介:程广玉(1987—),男,硕士,高级工程师,研究方向为化学电源,E-mail:chengguangyu12@126.com
  • 基金资助:
    国家重点研发计划项目(2022YFB3803400);2023年上海市促进文化创意产业发展财政扶持资金项目(2023010560)

Controlling electrolyte solvent components to enhance cycle life of LCO/C low-temperature 18650 batteries

Guangyu CHENG1(), Xinwei LIU2, Shuo LIU1, Haitao GU1, Ke WANG1   

  1. 1.State Key Laboratory of Space Power Sources, Shanghai Institute of Space Power-Sources, Shanghai 200245, China
    2.Shanghai Aerospace Power Technology Co. Ltd. , Shanghai 201112, China
  • Received:2024-05-06 Revised:2024-05-31 Online:2024-07-28 Published:2024-07-23
  • Contact: Guangyu CHENG E-mail:chengguangyu12@126.com

摘要:

低温18650电池的循环寿命一直是限制其发展的关键因素,为了实现长循环寿命与低温性能的兼顾,通过调控电解液溶剂组分,对比分析了不同电解液对电池倍率性能、高低温放电、荷电保持率、循环寿命、EIS阻抗变化等的影响。结果表明,电解液组分设计对电池性能有显著影响,通过低熔点的长链线性羧酸酯部分取代碳酸酯及短链羧酸酯,既可以实现较好的低温性能,同时又提升了高温稳定性。EP、PP的比例对于LCO/C电极体系循环稳定性有重要作用。其中溶剂组分EC+EP+PP(质量比2∶5∶3)具备最佳的综合性能,研制的LTB电池5C放电容量保持率达99.86%,-40 ℃/1C放电容量保持率达92.84%,循环1000次后低温-40 ℃/1C放电仍然达到初始低温放电容量的90%,常温循环1500次容量保持率达85%,低温-10 ℃循环500次容量保持率82.4%。

关键词: 低温, 18650电池, 电解液, 循环寿命, 锂离子电池

Abstract:

The cycle life of low-temperature 18650 batteries has always been a key factor that limited their development. To achieve a balance between a long cycle life and low-temperature performance, the effects of different electrolytes on rate performance, high- and low-temperature discharge performance, charge retention capacity, cycle life, low-temperature cycle performance, and EIS were compared and analyzed by adjusting the components of the electrolyte solvent. The results demonstrated that the design of the electrolyte composition had a significant impact on the performance of the battery. By partially replacing the carbonate esters and the short-chain carboxylic esters with long, linear carboxylic esters having a low melting point, impressive low-temperature performance as well as high-temperature stability were achieved, which illustrated that EP and PP play an important role in the cyclic stability of the LCO/C electrode system. The solvent component EC+EP+PP (mass ratio 2∶5∶3) exhibited the best comprehensive performance. The developed LTB battery maintained a discharge capacity retention of 99.86% at 5C and a discharge capacity retention of 92.84% at -40 ℃ and 1C. After 1000 cycles, the low-temperature discharge capacity at -40 ℃ and 1C was still 90% of the initial low-temperature discharge capacity. At room temperature, the cycling retention rate reached 85% after 1500 cycles; at a low temperature of -10 ℃, the cycling retention rate was 82.4% after 500 cycles.

Key words: low-temperature, 18650 battery, electrolyte, cycle life, lithium-ion battery

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