电极浆料涂布模头流场分析与结构优化

doi:10.19799/j.cnki.2095-4239.2024.0100

摘要/Abstract

摘要：

涂布工艺是锂电池极片制造过程的关键工序之一，涂层的稳定性和厚度一致性决定了极片的结构，进而影响电池的性能和循环寿命。大尺寸动力锂电池产品对涂布幅宽提出更高的要求，保证涂布模头出口处电极浆料的流动均匀性成为核心技术问题之一。因此，对涂布模头的流道结构进行合理优化显得尤为重要。本研究针对宽幅涂布模头出口速度分布不均的问题，构建了不同尺寸和结构的模头流道模型进行流场仿真，分析电极浆料在模头内部的流动特性，并采用Box-Behnken设计对衣架式模头的结构尺寸进行优化。具有倾斜变径式匀料腔结构的衣架式模头对浆料有更强的引流效果，有助于提升幅宽方向浆料流动的均匀性。采用Box-Behnken设计对衣架式模头的主要结构参数进行优化，使浆料的均匀性提升至0.99。

关键词: 锂离子电池, 狭缝涂布, 衣架式模头, 计算流体力学, Box-Behnken设计

Abstract:

The coating process is one of the key processes in the manufacturing of lithium battery electrodes. The stability and consistency of the coating determine the structure of the electrode, which in turn affects the performance and cycle life of the battery. As large-sized power lithium battery products had higher requirements for coating width, one of the core technical issues is how to ensure the flow uniformity of electrode slurry at the outlet of the coating die. Therefore, rational design of the flow channel structure of the coating die is crucial. This study aims to address the issue of inhomogeneous velocity distribution at the outlet of the wide coating die, and constructs die head flow channel models with different sizes and structures for flow field simulation. The flow characteristics of electrode slurry inside the die head are analyzed, and the structural dimensions of the coat-hanger die are optimized by using Box-Behnken design. The coat-hanger die with an inclined variable-diameter homogenizing cavity had a stronger drainage effect on the slurry, helping to improve the flow uniformity in the width direction. Adjustments to the die structure dimensions significantly impacted flow uniformity. The main structural parameters of the coat-hanger die were optimized using Box-Behnken design, resulting in an increase in the uniformity of the slurry to 0.99.

Key words: lithium-ion batteries, slot-die coating, coat-hanger die, computational fluid dynamics, Box-Behnken design

中图分类号:

TQ 024.1

杨家沐, 陈育新, 练成, 徐至, 刘洪来. 电极浆料涂布模头流场分析与结构优化[J]. 储能科学与技术, 2024, 13(4): 1109-1117.

Jiamu YANG, Yuxin CHEN, Cheng LIAN, Zhi XU, Honglai LIU. Flow field analysis and structural optimization of coating die with electrode slurry[J]. Energy Storage Science and Technology, 2024, 13(4): 1109-1117.

图/表 12

图1

图2

表1

模型结构参数及浆料性质参数"

参数	数值	单位
模头宽度，W	600, 800, 1000, 1200, 1400	mm
狭缝厚度，h	1	mm
模头高度，l	100	mm
进料管半径，r_l	5	mm
匀料腔半径，R	10	mm
二级匀料腔半径，r	4	mm
进料管长，L	80	mm
浆料密度，ρ	1320	kg/m³
浆料表面张力，σ	0.066	N/m
浆料黏度，μ	$M γ γ r e f N - 1$	Pa∙s
参考剪切速率，γ_ref	1	s^-1
流体一致性系数，M	3.585	Pa∙s
流动特性指数，N	0.6322	—
倾斜角，θ	0, 2.5, 5, 7.5, 10	(°)
衣架式匀料腔中心半径，R_h	10	mm
衣架式匀料腔端部半径，r_h	10, 7.5, 5, 2.5, 1	mm
扇形区高度，H	$W t a n θ$	mm
松弛区高度，y	40, 60, 80, 100, 120	mm

表1

图3

图4

图5

图6

图7

图8

图9

表2

Box-Behnken设计方案参数值"

序号	因素x₁：倾斜角	因素x₂：匀料腔端部半径	因素x₃：松弛区高度	均匀度 $U v$
1	0	0	0	0.91
2	1	0	1	0.956
3	-1	0	-1	0.805
4	1	0	-1	0.932
5	-1	0	1	0.875
6	0	0	0	0.91
7	0	-1	-1	0.748
8	0	1	1	0.982
9	0	1	-1	0.978
10	0	-1	1	0.823
11	-1	1	0	0.921
12	0	0	0	0.91
13	1	-1	0	0.861
14	0	0	0	0.91
15	-1	-1	0	0.748
16	1	1	0	0.874
17	0	0	0	0.91

表2

图10

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