What material is good for lithium battery casing?

The first type of lithium battery shell is a steel shell

In the early days, prismatic lithium batteries were mostly steel shells, which were mostly used for mobile phone batteries. Later, due to the low weight ratio of steel shells and poor safety, they were gradually replaced by aluminum shells and soft-packaged lithium batteries. But among cylindrical lithium batteries, there is another kind of sight Some manufacturers use steel as the battery shell material.

Because of the physical stability of the steel material, the pressure resistance is much higher than that of the aluminum shell material. After the design and structure optimization of various lithium battery manufacturers, the safety device has been placed inside the battery core, and the safety of the steel shell cylindrical battery has reached A new At present, most of the batteries of notebook computer batteries use steel shell as the carrier.

The battery steel shell needs to have certain corrosion resistance and high temperature resistance characteristics, which also have a great impact on the use of steel shell products. In the process of using steel shell products, users usually have low corrosion resistance or No resistance to high temperature environments will reduce the application of steel shell products. Therefore, when selecting steel shell products, it is necessary to meet the most basic production requirements.

The second type of lithium battery casing is an aluminum casing

The aluminum shell has beautiful appearance, good rigidity, light weight, sturdiness and durability, and is suitable for use in various environments. It is mainly used in square lithium batteries. The reason why lithium batteries are packaged in aluminum shells is that it is lighter and safer than steel shells. on. The aluminum shell alloy material structure has significant safety performance considerations, and this safety performance can be expressed by the material thickness and the swelling coefficient.

The reason why the lithium battery of the same capacity is lighter than the steel shell is that the aluminum shell can be made thinner. From the perspective of the working mechanism of lithium batteries, when charging, lithium ions are deintercalated, and the volume of the positive electrode expands; when discharging, lithium ions are inserted from the positive electrode and the negative electrode expands; both will cause physical expansion, and the swelling coefficient can be reduced through appropriate alloy formulations.

Lithium battery steel shell defects

There are many defects in battery steel shell. Some are caused by surface and internal defects of raw materials, and some are caused by stamping processing. The surface quality of the material is affected by the surface quality at the factory, as well as by the intermediate processing and distribution links, storage and use conditions. influences. Easy to draw, scratches, punctate pits and blisters.