Study On Automatic Homogenizing System Of Slurry For Lithium Ion Batteries

Lithium-ion batteries play an important role in the development of energy technology.At present,the slurry preparation technology of lithium-ion batteries has some problems,such as low efficiency,uneven slurry dispersion,low consistency of slurry and jelly phenomenon.In order to effectively solve the above problems,an automatic homogenizing system for lithium ion battery slurry was proposed.The system can automatically prepare the slurry for lithium ion batteries.It is also important to improve the production efficiency of slurry for lithium ion batteries,improve the quality of lithium ion batteries and protect the environment.The main research contents include the following aspects.1.Starting from the dry mixing process,through functional analysis,the module division of the automatic homogenizing system for lithium ion battery slurry is completed,and then the specific implementation of each module is analyzed.For the conventional module,the way of referring to the existing equipment is adopted,for the special module which the existing equipment can not achieve,the method of developing new equipment is adopted,and all modules are systematically combined.The whole process of dry mixing of lithium ion battery slurry is realized completely.2.The powder mixing module in the system is in front of the dry mixing process,which plays a supporting role for the follow-up process in the whole system.At the same time,the dry mixing effect of powder affects the quality of battery slurry.Therefore,the powder mixing module is deeply studied.Starting from the powder mixing theory,the dynamic analysis of the particles in the barrel is emphasized.Combining the mixing principle of mixer and the shape of particle movement,the movement of single particle,collision of binary particles and movement of particle group are analyzed,and the movement form of powder in barrel is obtained.Discrete element simulation software EDEM and fluid simulation software FLUENT were used to validate the movement form of powder in the barrel.The simulation results support the analysis of the movement form of particles.According to the similarity theory,the parameter proportion of model test is determined,and the existing conical screw mixer is simulated by model test,and the simulation results of existing equipment are obtained.The results show that the existing tape screw mixer can basically make the active material particles and conductive agent particles mix evenly when mixing the powder of lithium ion battery slurry.However,the particle size of adhesive particles differs greatly from that of other two kinds of particles.Particle segregation is easy to occur and can not be completely mixed uniformly..3.Aiming at the problems existing in powder mixing device,the optimization design is carried out.Firstly,the key parameters affecting the performance of the mixer are extracted,including the shape of the barrel,the speed of the agitator,the filling rate of powder and the form of the guide pipe.The influence law of the parameters on the particle segregation phenomenon is explored by the method of model test.The uniformity of the particle mixing is calculated by stratified sampling method,and the severity of the particle segregation phenomenon is described.Through several single variable model tests,the influence of each parameter on the mixing uniformity of the adhesive particles was obtained,and the range of the maximum mixing uniformity of the adhesive particles was obtained.Through orthogonal experiment,the cone of barrel,rotational speed of impeller and filling rate are divided into five levels,and the form of guide pipe is divided into three levels.The quasihorizontal method is used to integrate the form of guide pipe with less horizontal number into the other three factors,and the simulation is arranged according to the orthogonal experimental table after modification.Through range analysis and supplementary tests,the working conditions under which the uniformity of the binder particles reaches its maximum are obtained.4.Comparing the simulation results of the powder mixing device before and after optimization,the change of the uniformity of the three particles with the mixing time is obtained.Compared with before optimization,the optimized equipment can greatly improve the powder mixing uniformity,and realize the uniform mixing of three kinds of particle powder for lithium-ion battery cathode slurry,which lays a foundation for dry mixing of lithium-ion batteries.At the same time,the simulation results accord with the actual mixing experience to a certain extent,and verify the correctness of the particle model and mechanical model of powder material from the side,and the feasibility of using discrete element analysis to simulate powder mixing.