Numerical investigation on drying characteristics between hot wind and wet coating of battery electrode

In this paper, a three-dimensional dynamic drying model is established between hot wind and wet coating based on dynamic mesh method and multi-field coupling theory of porous media. This model considers the combined influences of hot wind and aluminum plate on drying characteristics of wet coating comprehensively based on meshless parallel method. It is proved to be reliable because its simulation data within the error range of plus/ minus 15 %. Through this model, the influences and distribution of different operating parameters on drying characteristics are analyzed for surface and interior of wet coating, and the velocity, temperature and relative humidity of hot wind are selected as 8 m/s-10 m s-1, 353.15K-373.15 K and 35 %-55 %, respectively. The results show that the drying processes of surface and interior can be accelerated effectively for wet coating by increasing velocity and temperature of hot wind, while the relative humidity has little effect on its drying characteristics. Meanwhile, the variation trends of wet coating with the drying time as 0-20 s, 20s-30 s and 30s-50 s are consistent with the acceleration, uniform and deceleration drying processes of porous media, respectively. Finally, the drying uniformity is compared for different partitions of wet coating. The results show that the growth gradient of drying non-uniformity with the increase of velocity is smaller than that with the increase of temperature. The change gradient of drying non-uniformity for wet coating with the change of temperature is larger than that with the change of velocity. For drying model in this paper, the optimal operating strategy when the velocity of hot wind is 8 m/s-10 m s-1, temperature is 363.15 K and relative humidity is 45% can be adopted to improve the drying uniformity of wet coating while reducing its total drying time in engineering. The research results provide an important theoretical basis for control parameters regulation of lithium-ion battery coating oven.