The impact of 18650 lithium ion battery manufacturing process on life

18650 lithium ion battery is one of the most common cylindrical lithium battery models, widely used in electric vehicles, digital home appliances, outdoor energy storage and other fields. In the production process of 18650 lithium-ion batteries, due to the different production processes, different brands of 18650 lithium batteries have unique characteristics. At the same time, the 18650 lithium-ion battery manufacturing process has a significant impact on the life span; in terms of ingredients , Pay attention to the addition of positive and negative materials. Generally speaking, the capacity of the negative electrode is generally required to be excessive relative to that of the positive electrode during the design and assembly process. If it is not excessive, the negative electrode will precipitate lithium during the charging process, forming lithium dendrites, thereby affecting safety. There is too much excess of the negative electrode relative to the positive electrode, and the positive electrode may be excessively delithified, causing the structure to collapse. The electrolyte is also a very important factor in the influence of the reversible capacity of the battery. The process of removing and inserting lithium ions from the electrode material is always a process of mutual use with the electrolyte, and this mutual use has an important influence on the change of the interface condition and internal structure of the electrode material. The electrolyte will be lost during the interaction with the positive and negative materials. In addition, part of the electrolyte will be consumed when the battery is formed into the SEI film and pre-charged. Therefore, the type of electrolyte and the amount of electrolyte also affect the battery life. The manufacturing process of lithium-ion batteries mainly includes: positive and negative electrode ingredients, coating, sheeting, winding, shelling, liquid injection, sealing, forming, etc. In the battery production process, the requirements for each step of the process are very strict. Any process that is not well controlled may affect the battery cycle performance. In the process of mixing positive and negative electrodes, attention should be paid to the amount of binder added, stirring speed, slurry concentration, temperature and humidity, and to ensure that the materials can be evenly dispersed. In the coating process, under the premise of ensuring the high specific energy of the battery, reasonably controlling the positive (negative) electrode coating amount and appropriately reducing the electrode thickness will help reduce the battery decay rate. The coated pole piece needs to be further compacted with a roller press. A suitable positive electrode compaction density can increase the discharge capacity of the battery, reduce the internal resistance, reduce the polarization loss, and extend the cycle life of the battery. When winding, the wound cell should be tight and not loose. The tighter the separator and the positive and negative electrodes are rolled, the smaller the internal resistance, but when the winding is too tight, it will be difficult to wet the pole piece and the separator, resulting in a smaller discharge capacity; too loosely rolled will cause excessive expansion of the pole piece during the charging and discharging process , Increase the internal resistance, reduce the capacity, and shorten the cycle life. 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: What are the performance parameters of 18650 lithium batteries