Magnetic Induction Heating Roll For Lithium Battery Electrode Roll Press Structural Optimization And Performance Study

Electrode roll pressing is an important process in the production of lithium ion batteries.The coated and dried loose electrode is compacted under the action of roll pressure to reduce the thickness of the electrode and enhance the stripping strength,so as to improve the energy density and cycle life of the battery.Compared with the traditional cold roll press,the hot roll press can greatly reduce the thickness of the pole plate rebound,reduce the roll pressure and enhance the binding strength between the active coating and the fluid collector.At present,thermal oil heating rolls are generally used in hot roll press.There are some problems,such as carbonization of thermal oil,long heating time,slow regulation response and low control accuracy,which cannot meet the needs of electrode roll press industry.Electromagnetic induction heating roll has the advantages of short heating time,wide temperature range,fast response,high control precision and environmental protection.In this paper,the structure and properties of electro-magnetic induction heating roll for polar roll press were studied by combining finite element simulation and experiment.In this paper,based on the technical requirements of hot roll pressing for lithium battery electrode,the structure scheme of direct and indirect electromagnetic induction heating was proposed,and the influence law of the thickness of roll sleeve on the steady-state temperature distribution and deflection deformation of electromagnetic induction heating roll was studied by finite element analysis.The reasonable thickness range of Φ900mm×1500 mm electromagnetic induction heating roll is 150～200 mm.The electromagnetic induction heating experiment platform was built,and the roll heating experiment under different power supply parameters was carried out.The influence of current size and frequency on the roll heating effect was analyzed,and the accuracy of the finite element analysis model of the roll electromagnetic induction heating was verified.The influence of thickness of heating layer,temperature equalization time,material and thickness of soaking layer on heating effect was simulated and the reasonable parameter range was determined.The heating structure of electromagnetic induction heating roll was selected as indirect induction heating structure by comparing the overall temperature distribution of the roll sleeve at the end of induction heating and at the steady state.The optimization strategy of roll heating performance was proposed from the aspects of power supply parameters,magnetic structure and heating time,and the influence of three optimization strategies on the heating performance of electromagnetic induction heating roll was studied by simulation.Combined with the optimization strategy,the roll surface temperature was controlled at 423±5 K,and the influence of the number of heating edges on the heating effect was analyzed by comparing the temperature uniformity of the roll surface at the end of heating and the steady-state time of the multilateral heating structure.Based on the indirect induction heating structure,the influences of external cooling intensity,cooling time and cooling position on the heating performance were studied.