Lithium battery structure cylinder

Cylindrical lithium battery cells are generally used in power batteries, such as the typical 21700 battery cells carried in the Tesla Model 3, which once made 21700 popular in the battery cell market. However, cylindrical cells are not the only advantages; their shortcomings are also obvious.

For instance, “65” represents a height of 65mm. Fifth Digit: The fifth digit indicates the cylindrical shape of the cell. Typically, it's “0” for cylindrical cells. By following this naming convention, we can easily identify the size and shape of cylindrical lithium-ion battery cells.

The following is a common cylindrical cell structure; see the image below for details: Ordinary cylindrical lithium-ion batteries consist of a casing, a cap, a positive electrode, a negative electrode, a separator, and an electrolyte. Generally, the battery casing is the battery's negative electrode, and the cap is the battery's positive electrode.

For the modeling of cylindrical lithium-ion batteries, detailed structural models including cathode material, cathode material, diaphragms, and shells can more accurately react to battery deformation and faults, and determine the failure position, but usually require significant computational costs and the model is particularly complex.

With the cylindrical cell format, the batteries can be applied to many applications, for example, power tools, laptops, portable electronic devices and electric vehicles. Figure 2 shows cylindrical lithium-ion batteries in a laptop and a power tool.

The size of a cylindrical cell is usually expressed by its diameter and length. For example, the 18650 battery has a diameter of 18 mm and a length of 65 mm, with 0 referring to the cylindrical type. 2. Chemical composition identification A battery's chemical composition may also be included in its name.