逗号刮刀涂布流场理论分析与数值模拟

doi:10.19799/j.cnki.2095-4239.2020.0364

摘要/Abstract

摘要：

逗号刮刀转移涂布是锂电池极片生产中的一种常用的涂布方式，研究涂布设备上刮刀狭缝高度与涂布湿厚度的关系具有重要的理论意义和实用价值。首先将二维流体力学基本方程纳维-斯托克斯方程按适用于刮刀涂布的条件简化为一维的雷诺润滑方程，进而应用于逗号刮刀的涂布流场研究。在该流场内，结合流场几何参数，建立了逗号刮刀压力微分方程。然后，以刮刀流场进口和出口压力为零作为边界条件，积分求解该方程，得到了涂布湿厚度与流场几何参数的关系式。研究发现，涂布湿厚度H_w与刮刀狭缝高度H₀的比值在几何参数K=R/2H₀的取值范围（10～2000）内趋近于2/3（0.66）。即使逗号刮刀上游几何尺寸有明显差距，它的无因次压力-位置曲线也几乎是重合的。作为该理论的验证，以Fluent软件建立了锂电池极片涂布的2D模型，通过软件参数设置中改变刮刀辊、涂布辊的半径，以及刮刀缝隙、涂布速度、涂布浆料黏度等模拟参数，求解涂布厚度并模拟流场行为。软件模拟与理论计算得到涂布厚度和流场压力分布结果高度吻合。另外，两者结果也表明涂布湿厚度H_w与刮刀狭缝高度H₀比值不受涂布浆料黏度变化和涂布速度变化的影响。本研究的结果可实际用于涂布技术人员对极片涂布厚度的预测，有助于提高极片涂布的效率并减少物料损失。

关键词: 涂布, 逗号刮刀, 涂布厚度, 理论分析, 数值模拟

Abstract:

Comma roll transfer coating is a common coating method in the production of lithium battery electrodes. Studying the relationship between the height of the coater gap on the coating equipment and the coating's wet thickness has important theoretical significance and practical value. In this work, we first simplify the basic two-dimensional equation of fluid mechanics, the Navier-Stokes equations, into a one-dimensional Reynolds lubrication equation according to the comma roll coating conditions and then apply it to the research. In this flow field, combined with its geometric parameters, a differential equation of pressure is established. Then, with zero pressure at the inlet and outlet of the flow field as boundary conditions, the equation is solved by integration, and the relationship between the coating wet thickness and the geometric parameters of the flow field is obtained. The study found that the ratio of the coating wet thickness H_w to the blade slit height H₀ is close to 2/3 (0.66) within the range of geometric parameter K=R/2H₀ (10—2000). Even if there is a significant difference in the upstream geometric dimensions, its dimensionless pressure-position curve is almost coincident. To verify this theory, we established a 2D model of lithium battery electrode coating with Fluent software and changed the radius of the doctor roller and coating roller and the height of the gap, coating speed, and coating slurry viscosity in the software parameter settings. The results of the software simulation and theoretical calculation of coating thickness and flow field pressure distribution are highly consistent. Both results show that the ratio of coating wet thickness H_w to blade slit height H₀ is not affected by changes in coating slurry viscosity and coating speed. The results of this study can be practically used by coating technicians to predict the coating thickness of electrodes, which helps improve the efficiency of the coating process and reduce material loss.

Key words: coating, comma roll, coating thickness, theoretical analysis, numerical simulation

中图分类号:

TM 911

梁卫华, 吴大勇, 舒均国. 逗号刮刀涂布流场理论分析与数值模拟[J]. 储能科学与技术, 2021, 10(2): 565-576.

Weihua LIANG, Dayong WU, Junguo SHU. Theoretical analysis and numerical simulation of comma roll coating flow field[J]. Energy Storage Science and Technology, 2021, 10(2): 565-576.

图/表 16

图1

图2

图3

图4

图5

图6

表1

表2

表3

图7

图8

表4

表5

表6

图9

图A1

参考文献 16

1	余雪松. 2019年我国锂离子电池发展回顾[J]. 新材料产业, 2020(4): 30-36.
2	申晨, 王怀国. 我国锂离子电池产业技术发展概况[J]. 新材料产业, 2019(9): 15-21.
3	巫湘坤. 锂离子电池浆料狭缝式涂布初期流场模拟研究[J]. 电源技术, 2018, 42(4): 500-503.WU Xiangkun. Simulation study on initial flow of slot-die coating for lithium-ion battery paste[J]. Chinese Journal of Power Sources, 2018, 42(4): 500-503.
4	赵伯元. 锂离子电池极片涂布技术和设备研究[J]. 电池, 2000, 30(2): 56-58.ZHAO Boyuan. Coating technology and equipment for lithium ion electrodes[J]. Battery Bimonthly, 2000, 30(2): 56-58.
5	COYLE D J, MACOSKOAND C W, SCRIVEN L E. Film-splitting flows in forward roll coating[J]. Journal of Fluid Mechanics, 1986, 171: 183-207
6	BENKREIRA H, EDWARDS M F, WILLKINSON W L. Mathematical modelling of the reverse and metering roll coating flow of Newtonian fluids[J]. Chemical Engineering Science, 1982, 37(2): 277-282.
7	包能胜, 刘小山, 马婉, 等, 辊式涂布两辊间隙施涂过程的数值计算分析[J]. 包装工程, 2016, 37(23): 6-12.BAO Nengsheng, LIU Xiaoshan, MA Wan, et al. Numerical calculation and analysis on roll coating process of the clearance between two rollers[J]. Packaging Engineering, 2016, 37(23): 6-12.
8	包能胜, 马婉, 黄学佳. 牛顿流体两辊间隙施涂过程的理论建模与分析[J] . 包装工程, 2017, 38(1): 31-36.BAO Nengsheng, MA Wan, HUANG Xuejia. Theoretical modeling and analysis of the coating process between two rollers of Newtonian fluid[J]. Packaging Engineering, 2017, 38(1): 31-36.
9	刘正士, 闫科, 王勇, 等. 涂料流场对逗号刮刀工作精度的影响[J]. 中国机械工程, 2012, 23(19): 2357-2361.LIU Zhengshi, YAN Ke, WANG Yong, et al. Influence of coating flow field on working precision of comma blade[J]. China Mechanical Engineering, 2012, 23(19): 2357-2361
10	SENENTXU L M, CARLOS M C. Printed Batteries: Materials, technologies and applications[M]. John Wiley & Sons Ltd, 2018: 63-79.
11	宫璐, 曹利娜, 张金龙. 流变仪在锂离子电池中的应用[J]. 电源技术, 2017, 41(5): 821-827.GONG Lu, CAO Lina, ZHANG Jinlong. Application of rheometer in lithium-ion battery[J]. Chinese Journal of Power Sources, 2017, 41(5): 821-827.
12	SCHMITT M, BAUNACH M, WENGERLER L, et al. Slot-die processing of lithium-ion battery electrodes—coating window characterization[J]. Chemical Engineering and Processing: Process Intensification, 2013, 68: 32-37.
13	SCHMITT M, DIEHM R, SCHARFER P. An experimental and analytical study on intermittent slot die coating of viscoelastic battery slurrie[J]. Journal of Coatings Technology and Research, 2015, 12(5): 927-938.
14	KISTLER S F, SCHWEIZER P M. Liquid Film Coating: Scientific Principles and Their Technological Implications[M]. Springer Science+Business Media Dordrecht, 1997: 548.
15	KAWABATA J. An analysis of highly viscous flow using Imai's complex function method with application toscreen printing[J]. Fluid Dynamics Research, 1992, 10: 11-23.
16	SULLIVAN T, MIDDLEMAN S. KEUNINGS R. Use of a finite-element method to interpretrheological effects in bladecoating[J]. AIChE Journal, 1987, 33(12): 2047-2056.

R_c/mm	R_r/mm	H₀/mm	R/mm	K	H_w/H₀
20	20	0.20	10	25	0.6640
40	40	0.20	20	50	0.6654
60	60	0.20	30	75	0.6658
80	80	0.20	40	100	0.6660
100	100	0.20	50	125	0.6661
40	50	0.05	22.22	222.2	0.6664
40	50	0.10	22.22	111.1	0.6662
40	50	0.15	22.22	74.07	0.6659
40	50	0.20	22.22	55.55	0.6657
40	50	0.25	22.22	44.44	0.6654
40	50	0.30	22.22	37.03	0.6651
40	50	1	22.22	11.11	0.6613
40	50	2	22.22	5.555	0.6552

K	25	50	75	100	125	222.2	111.1
P^*(-R,0)	2.11×10^-3	7.97×10^-4	8.47×10^-4	2.92×10^-4	2.10×10^-4	9.16×10^-5	2.60×10^-4
K	74.07	55.55	44.44	37.03	11.11	5.55
P^*(-R,0)	4.65×10^-4	7.08×10^-4	9.80×10^-4	1.27×10^-3	6.74×10^-3	1.54×10^-2

K	25	50	75	100	125	222.2	111.1
?H_g	0.0011	0.0016	0.0019	0.0022	0.0025	0.0002	0.0005
K	74.07	55.55	44.44	37.03	11.11	5.55
?H_g	0.0010	0.0015	0.0021	0.0027	0.0167	0.0473

μ/Pa·s	0.1	0.25	0.5	1	2	5	10
?H_g	0.0034	0.0014	0.0007	0.0003	0.0002	6.83×10^-5	6.83×10^-5
U^*/m·s^-1	0.005	0.025	0.05	0.10	0.20	0.40
?H_g	0.0014	2.7×10^-4	1.4×10^-4	6.8×10^-5	3.4×10^-5	1.7×10^-5

[1]	冯国会, 王天雨, 王刚. 封装方式对相变水箱蓄放热性能影响模拟分析[J]. 储能科学与技术, 2022, 11(7): 2161-2176.
[2]	叶文兰, 赵明, 胡明禹, 田扬. 管束式相变蓄热器的蓄放热性能分析[J]. 储能科学与技术, 2022, 11(7): 2151-2160.
[3]	李仲博, 汉京晓, 王成成, 杨慧, 杨娜, 尹少武, 王立, 童莉葛, 唐志伟, 丁玉龙. 热化学反应器放热过程模拟及参数影响规律[J]. 储能科学与技术, 2022, 11(7): 2133-2140.
[4]	吴小凌, 周涛, 刘钰照, 杜艳平, 陈会平, 李顺. 基于空气紊流的中空底孔微柱阵列设计及强化散热数值研究[J]. 储能科学与技术, 2022, 11(6): 1980-1987.
[5]	甘露雨, 陈汝颂, 潘弘毅, 吴思远, 禹习谦, 李泓. 锂电池安全性多尺度研究策略：实验与模拟方法[J]. 储能科学与技术, 2022, 11(3): 852-865.
[6]	张晓光, 潘晓楠, 李金铭, 刘丽, 何燕. 电池排布对锂电池组相变热管理性能的影响[J]. 储能科学与技术, 2022, 11(1): 127-135.
[7]	田辉, 华栋, 曼茂立, 刘春哲, 李国君, 张兄文. 板式固体氧化物燃料电池积碳特性的数值研究[J]. 储能科学与技术, 2022, 11(1): 291-296.
[8]	李正, 刘祯, 吴华伟, 谢东升, 钱伟. 涡旋压缩机切向泄漏瞬态流场特性[J]. 储能科学与技术, 2021, 10(5): 1579-1588.
[9]	刘丽辉, 张航, 彭子安, 李杰, 孙小琴. 板式相变储能换热器的性能优化[J]. 储能科学与技术, 2021, 10(5): 1745-1752.
[10]	王君雷, 徐祥贵, 孙通, 姚华, 宋民航, 王燕, 黄云. 一种螺旋翅片式相变储热单元的储热优化模拟[J]. 储能科学与技术, 2021, 10(2): 514-522.
[11]	邓婷婷, 蔡颖玲. 笼屉式水箱中膨胀石墨对石蜡熔化和凝固过程的影响[J]. 储能科学与技术, 2021, 10(1): 190-197.
[12]	邹燚涛, 裴后举, 施红, 朱信龙, 杨凯杰, 王均毅. 某型集装箱储能电池组冷却风道设计及优化[J]. 储能科学与技术, 2020, 9(6): 1864-1871.
[13]	李俊伟, 张恒运, 吴笑宇, 王　影. 基于热电制冷的动力电池模组散热性能研究[J]. 储能科学与技术, 2020, 9(6): 1790-1797.
[14]	周慧琳, 邱燕. 矩形单元蓄热特性及结构优化[J]. 储能科学与技术, 2020, 9(4): 1082-1090.
[15]	王烨, 蔺虎相, 胡悦, 王苗, 林源山. 半球形顶太阳能蓄热水箱内置错层隔板结构及运行参数优化[J]. 储能科学与技术, 2020, 9(3): 942-950.