| Li-ion battery is a widely used power battery.As the core of li-ion battery,the drying quality of electrode film directly determines the overall performance of the battery.Air knife is the core component of the electrode film drying chest.Traditional chest-type hot-air drying system has many designs for air return of the air knife,such as return air on both sides,interval return air and comprehensive return air.These return air methods often cause problems such as edge curling and cracking due to excessive concentration of return air flow.Therefore,through theoretical analysis and numerical simulation,this paper aims at exploring the hole-array impingement jet drying pattern suitable for li-ion battery electrode film drying process and studying its flow field characteristics in order to reduce drying defects caused by air return and improve drying efficiency and quality of the electrode.The flow pattern and flow field characteristics of the hole-array impinging jet were analyzed,and combined with the structural characteristics and existing problems of the traditional drying chest.A structure of the li-ion battery electrode array impinging jet drying chest was proposed and a physical model was established.Using Solid Works software,a numerical simulation calculation model for two types of hole-array configurations(the main flow equalizing elements in the drying chest)was initially established.And its steady flow field was obtained through the finite volume method.A comparative study was conducted on the flow field characteristics formed by two configurations on the electrode surface,verifying the correctness of the hole-array configuration design idea and the rationality of the new return air method design.At the same time,a design principle perspective for optimizing and improving the configuration of hole-array was proposed,which is to increase the layout density of hole-array within the allowable range of the process.Three design schemes of two hole-array configurations were simulated in a drying chest,and the distribution characteristics of the flow field inside the drying chest and on the electrode surface were compared and studied.It was concluded that appropriately increasing the layout density of the hole-array can effectively improve the stability and uniformity of the electrode surface flow field.The flow field characteristics of three schemes of the two configurations were compared and analyzed using the unified index of the uniformity of the field parameters on the electrode surface as the evaluation criterion.Taking into account factors such as the heat transfer uniformity of the electrode coating,the heat transfers of the substrate at the edge of the electrode,and the overall wind resistance of the drying chest,a hole-array configuration and parameters were determined to achieve better flow field uniformity and reasonable return air.Based on the optimization scheme of the square array,the variable operating flow field characteristics of the drying chest were studied,and the effects of drying parameters such as drying distance,inlet wind speed,and inlet air temperature on the surface flow field of the electrode were analyzed.The analysis shows that reducing the drying distance and inlet air velocity can effectively improve the uniformity of the flow field on the entire drying chest and the electrode surface under actual operating conditions,while changing the inlet air temperature has little impact on the flow filed distribution. |
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