What are the types of lithium-ion battery casing materials?

February 5, 2021

What are the types of lithium-ion battery casing materials?
1. Steel shell
In the early days, prismatic lithium-ion 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-ion batteries.
However, among cylindrical lithium-ion batteries, there is another situation. Most manufacturers use steel as the battery shell material. Because of the physical stability of steel materials, the pressure resistance is much higher than that of aluminum shell materials. After the design structure is optimized, the safety device has been placed inside the battery core, and the safety of the steel shell cylindrical battery has reached a new level. At present, most of the battery cells of the notebook computer use the steel shell as the carrier.
2. Aluminum shell
Aluminum shell is a battery shell made of aluminum alloy material. It is mainly used in square lithium-ion batteries. The reason why lithium batteries are packaged in aluminum shell is that it is lighter in weight and safer than steel shells.
The aluminum shell is designed with square and rounded corners. The material of the aluminum shell is generally aluminum-manganese alloy. The important alloy components it contains are Mn, Cu, Mg, Si, Fe, etc. These five alloys are used in the aluminum shell of lithium-ion batteries. Play different purposes, such as Cu and Mg to improve strength and hardness, Mn to improve corrosion resistance, Si can enhance the heat treatment effect of magnesium-containing aluminum alloy, Fe can improve high temperature strength.
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-ion battery of the same capacity is lighter than the steel shell is that the aluminum shell can be made thinner.
Lithium-ion batteries are very important in terms of appearance design. Exquisite appearance is one aspect. The most important thing is to protect the battery core and internal circuits, so that the overall battery meets special requirements such as waterproof and shockproof.