What Is The Thickness of Aluminum Foil Battery

As we all know, the four main parts of lithium-ion batteries are positive electrode material, negative electrode material, separator and electrolyte. However, in addition to the main four parts, the current collector used to store the positive and negative materials is also an important part of the lithium battery.

For lithium-ion batteries, the commonly used positive current collector is aluminum foil, and the negative current collector is copper foil. In order to ensure the stability of the current collector inside the battery, the purity of both is required to be above 98%.

The aluminum foil thickness has been reduced from 16um to 14um and then to 12um in previous years. Now many battery manufacturers have used 10um battery foil, even 8um. As for the copper foil for the negative electrode, due to its better flexibility, its thickness has been reduced from 12um to 10um and then to 8um. Up to now, a large number of battery manufacturers use 6um in mass production.

Why use copper foil for the negative electrode and aluminum foil for the positive electrode?

Firstly, copper and aluminum foil has good conductivity, soft texture and low price. copper and aluminum foil has good conductivity, soft texture and low price. Among the metal materials, copper foil and aluminum foil are cheap and conductive.

Secondly, copper and aluminum foil is relatively stable in the air. Aluminum is easy to chemically react with oxygen in the air, forming a dense oxide film on the aluminum surface layer to prevent further aluminum reaction, and this thin oxide film also has a certain protective effect on aluminum in the electrolyte. Copper itself is relatively stable in air, and basically does not react in dry air.

Finally, the potential of the positive and negative electrodes of the lithium battery determines the aluminum foil for the positive electrode and the copper foil for the negative electrode, not the other way around. The positive electrode potential is high, the copper foil is easily oxidized under high potential, and the oxidation potential of aluminum is high, and the surface of the aluminum battery foil has a dense oxide film, which also has a better protective effect on the internal aluminum.