| With the continuous development of the global economy and the outbreak of energy crisis,the research of new energy plays a vital role in the sustainable development of mankind.As a new energy storage carrier,lithium battery has been widely used in daily life and industrial production in recent years.Negative electrode is an important part of lithium battery,and the drying process is an important part of lithium battery production.In the process of drying,the water transfer and heat transfer law of negative electrode coating is the theoretical basis for the production process and energy saving,which also plays a guiding role in the design and operation of the drying equipment.Therefore,it is of great theoretical significance and practical value to study the drying process of anode film.This study selected graphite and conductive carbon black as anode materials,use of thickener and binder as material ratio,pulp,coating,is made of graphite anode coating and drying equipment in the implementation of the drying process,get a piece of coating drying process of the main characteristics and basic rules.(1)This paper discusses the theory model of air convection drying coating,analyses the typical material drying rule,to determine the nature of the drying medium of air(temperature,speed,humidity,etc.)as the main influence parameters of the experimental study of dry.(2)Basic experiment.As the drying equipment,the temperature of hot air and coating thickness were selected as the main variables of the experiment.Coating thickness is 100 microns,respectively 150 microns and 200 microns,the hot air in the cabinet speed is about 0.5-1m/s,hot blast temperature,respectively,set to 80?,90?,100? and 110?.During the experiment,the real time weight and surface temperature were measured,and the dry base moisture content of the coating was calculated,then the drying rate of the coating was obtained and the drying characteristic curve was made.The experimental results show that the higher the temperature,the thinner,the shorter the time required to achieve the equilibrium moisture content,and the higher the drying rate.The effect of hot air temperature on the drying speed is great,and the drying speed of coating with different thickness is not very different.(3)On the basic rule of the basic experiment proved,for further comprehensive study of different thickness of coating in hot air drying characteristics of speed,temperature conditions,the selection of different air temperature(80?,90?,100?,110?),the different wind speed(1.1m/s,1.7m/s,2.3m/s)and different thickness(100?m,150?m,200?m)as the experimental variables,use the special coating and drying system implementation of drying process of laboratory.Experimental results show that the effects of air temperature and coating thickness on the drying rate law is consistent with the basic experiment,coating drying process including interest rate drying stage,constant speed stage of drying and falling rate drying stages;The speed of hot air also has a certain influence on the drying speed,the higher the wind speed,the higher the drying speed.Relative to the electric drum wind drying oven,special coating and drying system flow effect is good,slow down period of movements smooth coating temperature curve,the drying curves and drying rate curve and basic experiment are basically identical.(4)To seek a kind of applicable to describe the properties of lithium battery pole piece coating theory model,based on the experimental data,the drying model of 10 kinds of typical nonlinear fitting and analysis of variance,the results showed: compared with other nine models,Wang and Singh model is the biggest decision coefficient,minimum weighted chi-square coefficient and standard error.Therefore,this paper chooses this model to describe the water changes of the polar film coating in the drying process,and simulates the physical constants A and B in the model equation. |
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