| In the process of using hot air to dry lithium battery electrodes,in order to improve production efficiency,production personnel will further increase the drying temperature and wind speed.But at the same time,it will also deteriorate the drying environment,causing cracks of different shapes to appear in the coating of lithium battery electrodes after hot air drying.The cracks generated on the surface of the coating will block the movement channels of particles,thereby shortening the service life of the battery product.In order to explore how variables affect the cracking behavior of lithium battery electrode plates during drying,this article conducted the following research from both theoretical and experimental perspectives.The variables include wind temperature,wind speed,distance between the wind blade and the electrode,and wet thickness of the coating.In terms of theoretical research,based on the drying process and cracking mechanism of coating materials(latex),the drying cracking mechanism of lithium battery negative electrode coating(solutes are graphite and carbon black)was explored.The relationship between drying conditions such as wind temperature,wind speed,distance between wind blade and electrode,and coating wet thickness,as well as the degree of cracking and crack morphology of lithium battery electrode coating,was obtained: an increase in any variable of wind temperature,wind speed,and coating wet thickness during the drying process will exacerbate the degree of cracking of lithium battery electrode coating;An increase in the distance between the wind blade and the electrode will reduce the degree of cracking in the coating of the lithium battery electrode.The evolution of surface cracks on lithium battery electrodes and the development of drying frontiers were tracked using endoscopic observation.After the crack morphology(size)develops to a certain extent,there is no significant change,and the number of cracks continues to increase,and the cracks gradually develop to the overall situation after being concentrated and distributed at a certain location.Due to the influence of transverse drying mode on the drying process of the coating edge area,the drying front starts from the edge and retreats towards the central area,stopping at a certain distance from the central area.Through orthogonal experiments,image analysis software is used to process the surface images of lithium battery electrode coatings and quantify crack morphology indicators δ,Sort the four variables mentioned above based on their impact on the degree of cracking in the coating of lithium battery electrodes: wind temperature has the greatest impact on the surface crack area of the coating,followed by the distance between the wind blade and the electrode,and wind speed has the smallest impact on the surface crack area of the coating.Thus,the main influencing factor for cracking can be found: temperature.The critical conditions for coating surface cracking of lithium battery electrodes under different drying conditions were obtained through controlled variable experiments.The experimental relationship between the degree of surface cracking of the electrode coating and wind temperature,wind speed,distance between the blade and the electrode,and the wet thickness of the coating was obtained.The morphology of cracks on the surface of the electrode coating is evaluated based on the average length,average width,and number of openings of a single crack.The crack spacing is represented by the number of cracks,and the influence of wind temperature,wind speed,distance between the wind blade and the electrode,and coating wet thickness on the crack morphology and distribution is obtained,verifying the correctness of theoretical research. |
PDF Full Text Request