battery 18650 rechargeable

　　What is the impact of the design and manufacturing process of 18650 lithium-ion batteries

　　In terms of ingredients, pay attention to the amount of positive and negative materials added. Generally speaking, in the process of design and assembly, it is generally required that the capacity of the negative electrode is more than that of the positive electrode. If it is not excessive, lithium will be precipitated from the negative electrode during the charging process, forming lithium dendrites, which will affect safety. The negative electrode is too much in excess of the positive electrode, and the positive electrode may be delithiated excessively.

　　In terms of ingredients, pay attention to the amount of positive and negative materials added. Generally speaking, in the process of design and assembly, it is generally required that the capacity of the negative electrode is more than that of the positive electrode. If it is not excessive, lithium will be precipitated from the negative electrode during the charging process, forming lithium dendrites, which will affect safety. If the negative electrode is too much in excess of the positive electrode, the positive electrode may be delithiated excessively, 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 intercalating lithium ions from electrode materials is always a process of interaction with the electrolyte, which has an important impact on the interface conditions and internal structure changes of electrode materials. The electrolyte will be lost in the process of interacting with the positive and negative electrode materials. In addition, when the battery is formed to form an SEI film and pre-charged, part of the electrolyte will also be consumed. Therefore, the type of electrolyte and the amount of liquid injection also affect the battery life.

　　The manufacturing process of lithium-ion batteries mainly includes: positive and negative electrode ingredients, coating, sheet production, winding, shelling, liquid injection, sealing, chemical formation, 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.

　　During the batching process of positive and negative electrodes, attention should be paid to the amount of binder added, stirring speed, concentration of slurry, temperature and humidity, and to ensure that the materials can be dispersed evenly.

　　In the coating process, under the premise of ensuring high specific energy of the battery, reasonably controlling the coating amount of the positive (negative) electrode and appropriately reducing the thickness of the electrode will help reduce the battery decay rate. The coated pole piece needs to be further compacted with a roller press. Appropriate positive compaction density can increase the discharge capacity of the battery, reduce internal resistance, reduce polarization loss, and prolong the cycle life of the battery.

　　When winding, the rolled battery core should be tight and not loose. The tighter the separator and the positive and negative electrodes are rolled, the smaller the internal resistance, but if the roll is too tight, it will cause difficulty in wetting the pole piece and the separator, resulting in a smaller discharge capacity; if the roll is too loose, the pole piece will excessively expand during the charging and discharging process. , increased internal resistance, reduced capacity, and shortened cycle life.