Before moving on to Formation, I would like to explain the cylindrical assembly process. The cylindrical shape has a simple structure and the cell quality variation is small gap that compared to other form factors. Cylindrical type have advantage for various types pack producing, there are no restrictions on size and structure. And It has excellent productivity, so if one line is built, 200 to 350 cells per minute can be produced. However, if the accumulated know-how in the assembly process and the delicate difference in manufacturing are not managed, on the contrary, difficulties in production occur due to mass defects.
These advantages were the reason why Tesla adopted the cylindrical cell. And, it is manufactured in a unified standard of 1865 and 2170 to diversify cell suppliers and take cost advantage as competition by cell suppliers. However, almost over 10years only Panasonic and LG Energysolution are only adopted for Tesla cell suppliers for cylindrical cell still, the reason is that because the technological barriers to entry and cost competitiveness according to productivity were higher than expected. The cost competitiveness of the two companies is also strong, but the high production yield is still at a level that cannot be realized in Pouch and Prismatic for cell manufacturers.
Cylindrical assembly is largely divided into two processes: electrode winding and assembly cell. Today I will explain about Electrode winding.
Electrodes coated on aluminum and copper foil are separated by two separators and wound in a circle. Due to these structural characteristics, the initial cylindrical shape had a lot of influence on the quality of the process depending on the characteristics of this separator. And, the production length and structure of this separator had an effect on the tolerance management of assembly quality. It can bring about changes in electrical capacity depending on the thickness and length of the electrode, but cell manufacturers face a limit due to the characteristic of having to put it into a can structure of a certain standard. In particular, if the electrode winding is proceeded to an extreme state, the eletrolyte may not be evenly distributed in the next assembly process, or the produced seperator may be removed.
Barriers to entry are also high in the manufacture of equipment. Although some large companies in China are entering the market with price competitiveness, cell manufacturers are ignoring them due to various quality and operation problems, and Japanese traditional manufacturers are being pushed behind in terms of productivity and price competitiveness and the demands of various cell manufacturers. Reality. And, even now, the market is monopolized by a very small number of companies due to the technology gap according to the technology reproduction method and know-how, and there is a high demand for diversification of cell manufacturers.
Next, the cylindrical assembly process will be explained continuously.
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