Common failure methods and corresponding preventive measures of lithium battery cathode materials

As we all know, cathode material is the key material center of lithium battery, its function affects the direct policy of each function of lithium battery, lithium battery cathode material, the current market includes lithium cobalt oxide, lithium manganate, lithium iron phosphate, ternary materials and other products. Compared with other lithium battery raw materials, cathode materials are more diversified, the processing process is more chaotic, and the risk of quality failure is higher, so the requirements for quality treatment are also higher. This article discusses the common failure methods and corresponding preventive measures of lithium battery cathode materials from the perspective of material users. The positive electrode guesses that there is a metal foreign matter. When the positive information and guesses are iron (Fe), copper (copper), chromium (Cr), nickel (nickel), zinc (zinc), silver (Ag), and other metal impurities, the battery reaches the metal The oxidation of the elements into the phase voltage recovery potential will first oxidize the metal cathode at the anode. When the cathode metal elements accumulate to a certain extent, the accumulation of solid metal edges will pierce the diaphragm and form battery self-discharge. Self-discharge has a fatal effect on lithium batteries, so it is particularly important to prevent the introduction of metal foreign bodies at the source of lithium batteries. Positive material moisture exceeds the standard. Most cathode materials are micron or nano particles, which can easily absorb moisture in the air, especially the preparation of ternary materials with high content (N, that is, positive paste. It is assumed that the positive material has high moisture and the mixing process The water absorption of the middle paste NMP will cause the solubility of PVDF to decrease, which will cause the paste gel jelly and affect the processing function. After the battery is completed, its capacity, internal resistance, circulation, and multiplier are all affected, so the moisture content of the anode material should be the same as the metal foreign matter As a key control item. Poor batch consistency of positive materials. For battery manufacturers, the smaller the difference between different batches of cathode materials, the better the consistency, and the more stable the function of the product battery. We all know that lithium iron phosphate cathode materials It is the most important shortcoming of poor batch stability. In pulping, it is usually due to large batches shaking, and the viscosity and solid content of each batch of mud are unstable, which brings troubles to users, and it is a habit to constantly adjust the process. Of course, With the advancement of technology, material suppliers improve the process, and the dispersion of physical policies is getting smaller and smaller, and the step of viscosity testing before delivery can be eliminated. In addition to the above-mentioned methods to improve consistency, we should also use To minimize the instability and prevent the occurrence of quality problems. First of all, from the following aspects. (1) The formulation of operating procedures. The internal quality of the product is not only planned, but also manufactured. Therefore, how the operator controls the processing quality is particularly important, and specific operating standards should be formulated. (2) The recognition of different concepts. The key policies and key processes that affect product quality are tested and identified, and these key control and control The policy should be specially monitored, and corresponding emergency measures should be formulated. The mainstream of the preparation of lithium iron phosphate on the phosphate railway line, this process includes batching, ball milling, sintering, destruction, packaging, etc., the key process of the ball milling process, because of a Assuming that the particle size consistency is not well controlled in the ball mill, the product particle size uniformity will be affected, which will affect the batch consistency of the material. (3) The application of SPC. The key characteristic parameters of the critical process are monitored by SPC from time to time, and abnormal points are monitored. Analyze and find out the cause of unsafety, and adopt effective and correct methods and protective methods to prevent bad items from flowing to customers. Other unfavorable conditions are pulping, the solvent, glue, and conductive agent of the cathode material of the pulping tank are mixed evenly in a certain proportion. The materials and export equipment filters are designed to prevent large cathode particles and foreign bodies from guessing and ensure the quality of the coating. Statement: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete the previous article: Analyze what is a lithium battery failure