Influence of Pole Sheet Manufacturing on the Performance of Lithium-ion Batteries
Briefly describe the influence of pole piece manufacturing on the performance consistency of lithium-ion batteries
The coating process is divided into three sections, one is the slurry feeding system, the other is the coating system, and the third is the pole piece drying system. The Holy Trinity requires each system to be stable in order to ensure the consistency of the pole piece.
The slurry feeding system is to transfer the stirred slurry to the storage tank, then transfer it to the transition cylinder through the diaphragm pump, and then use the screw pump to stably output the slurry to the coating equipment through the filter device and the iron removal device Apply. Several points that need to be paid attention to in the slurry automatic feeding system are: preventing the stratification of the slurry in the storage tank, the level of the slurry in the transition cylinder, the stability of the screw pump, and the blockage of the filter tank should be cleaned in time.
The coating methods of lithium battery slurry mainly include comma blade coating, transfer coating, and slit extrusion coating. The three coating methods have their own characteristics. The scraper type is mainly used in laboratory conditions, the transfer coating is mainly used in the production of 3C batteries, and the slot extrusion coating is mainly used in power batteries. The parameters that characterize the stability of the pole piece are mainly the surface density of the pole piece, the thickness of the pole piece and the cohesiveness. In the coating system, the factors that affect the consistency of the pole piece mainly include the manufacturing accuracy of the coating head, the stability of the slurry conveyed by the screw pump, the stability of the compressed gas, the speed stability and the control of the dynamic tension.
The pole piece drying system is mainly composed of several ovens with different temperature distributions, the purpose is to dry the pole pieces. What needs to be paid attention to in the drying system is the setting of the drying temperature. If the temperature is too high during the coating process, it will easily lead to cracking of the pole piece. If the temperature is low, the pole piece will not be completely dried, which will cause the local polarization of the battery to be inconsistent. In addition, attention should be paid to preventing the adhesive from floating.
The problems that often occur in the coating process are defects such as thick head and thin tail, thick sides on both sides, dark spots, rough surface, and exposed foil. The thickness of the head and tail can be adjusted by the switching time of the coating valve or intermittent valve. The problem of thick edge can be improved from the aspects of slurry properties, coating gap adjustment, slurry flow rate, etc. The surface is rough, uneven and streaked, etc., can be solved by stabilizing the foil , Reduce the speed, adjust the angle of the air knife and other improvements.