What are the key processing techniques for lithium batteries

It can also be called mixing, homogenization, pulping, batching, and so on. Through certain feeding sequence, stirring process, vacuum control, temperature control and other conditions, the key components such as positive and negative active materials, conductive agents, binders, solvents, etc. are prepared into non-Newtonian fluids with certain viscosity requirements and particle size requirements (non-Newtonianliquids) process. The properties of the slurry to be controlled are that it has good fluidity, and the viscosity and particle size meet the coating requirements. 2. Coating Some companies call it coating. Coating is the process of evenly coating the stirred slurry on the current collector and drying it to form pole pieces. Coating methods include continuous coating and intermittent coating. Lithium battery slurry coating methods mainly include doctor blade direct coating, doctor roller coating, and slot extrusion coating. The control parameters of the coated product are areal density, cohesiveness, and moisture content. 3. Rolling (Pressing) Rolling refers to the process of passing the coated product through two steel rolls under a certain gap and under a certain pressure to compact the pole piece to a specified thickness. The influencing factors of rolling include feed angle, gap value, pressure value, rolling speed, winding tension, pole piece temperature, etc. The purpose of rolling is to further compact the loose and porous electrodes, reduce the contact resistance between substances, increase the battery capacity within a certain battery volume, and not overpressure to ensure the electrolyte's infiltration effect on the pole pieces. 4. Slitting is also called slitting. The width of the coated pole piece is large, and the pole piece should be cut into multiple pieces. Slitting products are critically affected by the quality of the cutter, the angle of the cutter, and the tension. 5. Tab Forming is a process in which the pole piece is cut by the engagement between the upper and lower die of the control equipment, so that the pole piece forms a tab according to the design size requirements. 6. Electrode Defects (ElectrodeDefects) Electrode defects appear in all stages of pole piece processing. Thick head, thin tail, thick edges, exposed foil, unstable surface density, horizontal and vertical stripes, dry material, pinhole shrinkage are easy to appear during coating. , Leukoplakia, pitting, foreign bodies, etc., detailed reasons for detailed decomposition. The most important defects of the rolled pole piece include uneven winding, wrinkles, thickness rebound, material drop sticking to the roller, particles, and thickness instability. Defects of pole piece slitting include wave edge, burr, curling, material drop and so on. 7. Winding Winding is a way of composing batteries, which is suitable for cylindrical batteries, square batteries and soft pack batteries. By controlling the speed, tension, size, deviation and other factors of the equipment, the negative pole piece, positive pole piece and diaphragm with matching size after slitting are rolled into a bare cell. The main point of winding is that the separator wraps the positive and negative electrodes, and the negative pole piece should wrap the positive pole piece. This requires that the negative pole piece cannot be exposed to the foil. After the foil is exposed, it will cause the partial lithium release of the pole piece to pierce the diaphragm and cause a short circuit. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to recycle used lithium iron phosphate batteries?