Why are hard-shell lithium batteries made of cylindrical shape?

Why are hard-shell lithium batteries like the 18650 made into a cylindrical shape? Essentially, the 18650 was originally intended to be developed in cooperation with Sony's portable camera battery compartment scale alone. Sony is the founder and inventor of lithium batteries in 18650, and Sony itself is a leader in the electronics industry. Therefore 18650 soon became the industry standard. Next is the core question, why is it a cylinder? It can be viewed from two aspects, 1. Strength: Lithium batteries are risky, especially in today’s high-nickel triads, steel needle puncture, external impact, The impact causes cell deformation, etc. All it wants is a problem with the film, which causes an internal short circuit, causing the film to explode and burn at a temperature of 6,700 degrees. The arc shape is conducive to the tension. The square is slightly worse in this respect. So from a safety point of view, steel cylinders are the first choice. 2. Processing cost From the perspective of strength, honeycomb diamonds are also good. However, the processing cost is much lower. The folding process is more troublesome, the power is not as high as winding, and the cost is higher than winding. The size of the current square battery is very large, so the cost is controlled by reducing the frequency of the folding process per Wh. Therefore, when manufacturers want to make small grid positioning, they will give priority to the cylinder (the shell of the soft package is basically airy, and only the final heat pressing on the square mold can make the aluminum plastic film, which is more costly than the hard shell folding. Low) Therefore, it is still related to product positioning and users. The greater the power, the larger the volume, and the more orderly use of battery space. It is suitable for large square hard-shell batteries, so it can reduce the difficulty of many groups of wiring and handling. And cost. For example, electric buses. Some of the shapes are changeable, less regular, or less used, and the most important are cylinders. For example: Power tools are extremely harsh on space in soft packaging. Such as mobile phones, digital, wearable devices, etc. Statement: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: Explanation of the difference between Ni-MH battery and lithium battery