储能科学与技术 ›› 2023, Vol. 12 ›› Issue (6): 1957-1967.doi: 10.19799/j.cnki.2095-4239.2023.0056

• 储能测试与评价 • 上一篇    下一篇

圆柱形锂离子电池真空干燥过程的数值模拟

陈育新1(), 杨家沐1, 李东博2, 练成1,2(), 刘洪来1,2   

  1. 1.化学工程联合国家重点实验室，华东理工大学化工学院，上海 200237
    2.华东理工大学化学与分子工程学院，上海 200237
  • 收稿日期:2023-02-09 修回日期:2023-04-12 出版日期:2023-06-05 发布日期:2023-06-21
  • 通讯作者: 练成 E-mail:cyxin99@foxmail.com;liancheng@ecust.edu.cn
  • 作者简介:陈育新（1996—），男，博士研究生，研究方向为锂离子电池极片制造工艺，E-mail：cyxin99@foxmail.com；
  • 基金资助:
    国家自然科学基金(22278127);中央高校基本科研业务费专项资金(2022ZFJH004)

Numerical simulation of the vacuum drying process of cylindrical lithium-ion batteries

Yuxin CHEN1(), Jiamu YANG1, Dongbo LI2, Cheng LIAN1,2(), Honglai LIU1,2   

  1. 1.State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
    2.School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China
  • Received:2023-02-09 Revised:2023-04-12 Online:2023-06-05 Published:2023-06-21
  • Contact: Cheng LIAN E-mail:cyxin99@foxmail.com;liancheng@ecust.edu.cn

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摘要：

极片中的水分对锂离子电池的性能和安全有重要影响，在生产中需要通过真空干燥对其进行严格控制。目前对于真空干燥工艺的研究以实验为主，消耗了大量的能源、材料以及人力资源，且耗时较长。针对以上问题，以18650电池为研究对象，建立了扩散-流动-热传导-气液传质耦合的二维旋转模型，准确预测了真空干燥过程中电芯含水率的变化。结果表明，过程中电芯不同位置的温度、水蒸气分压、含水率较为均匀，采用均质的零维模型同样能得到准确结果；电芯材料的颗粒尺寸、孔隙率、初始含水率对水分蒸发速率有显著影响，达到相同干燥程度所需的时间相差数个小时；平衡含水率取决于温度和空气湿度，二者是影响最终含水率的主要因素；提高电芯的温度或降低烘箱的出口压力均可提高真空干燥的效率，获得更低含水率的电芯产品；以更快的速度加热电芯，更早进入真空阶段可以显著提升前期的干燥效率；在进入真空阶段后以一定频率对烘箱进行换气可以降低电芯中水蒸气分压，进而提升干燥速率，既能降低最终含水率，也可节约时间成本。本工作提出的预测模型可以快速、便捷地研究各工艺参数的影响，在锂离子电池真空干燥工艺参数优化方面具有应用价值。

关键词: 锂离子电池, 制造工艺, 真空干燥, 数值模拟

Abstract:

The moisture content in electrode sheets significantly affects the performance and safety of lithium-ion batteries, necessitating strict control through vacuum drying during production. Currently, vacuum drying research mainly relies on time-consuming experiments that utilize substantial energy, materials, and human resources. To address these issues, we developed a two-dimensional rotating diffusion-flow-heat conduction coupling model using an 18650 battery as the research model, which accurately predicted the change in the moisture content of the cell during the vacuum drying process. The results show that the temperature, water vapor partial pressure, and water content at different core positions are relatively uniform, and the homogeneous zero-dimensional model can yield accurate results. The core material's particle size, porosity, and initial moisture content significantly impact the water evaporation rate, with drying time varying by several hours to reach the same dryness level. The equilibrium moisture content depends on temperature and air humidity which are the main factors affecting the final moisture content. Enhancing the cell's temperature or reducing the oven's outlet pressure can improve vacuum drying efficiency and yield products with lower water content. Heating the core more rapidly and transitioning to the vacuum stage earlier can significantly improve early-stage drying efficiency; after entering the vacuum stage, periodic air exchange in the oven can lower the core's water vapor partial pressure, thereby enhancing the drying rate and reducing the final moisture content, saving both time and cost. The proposed prediction model provides a fast and convenient method for studying the impact of various process parameters and has application value in optimizing lithium-ion battery vacuum drying process parameters.

Key words: lithium-ion battery, manufacturing process, vacuum drying, numerical simulation

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