Composite aluminum foil also has a sandwich structure, "metal Al layer-organic polymer layer-metal Al layer". Its organic polymers are still divided into PET, PP, and PI.
The density of polymer substrates is small, with the density of PET material being 1.38g/cm³, PP material being 0.89-0.91g/cm³ and PI material being 1.38-1.40g/cm³. Assuming that we use 8 μm composite aluminum foil (1 μm Al layer + 6 μm PET + 1 μm Al layer) instead of the traditional 12 μm aluminum foil, the weight can be reduced by more than 50% per unit area.
There are two mainstream production processes for composite aluminum foil:
One is magnetron sputtering + evaporation
The second is pure evaporation
Advantages: Effectively increase energy density and improve safety performance.
Disadvantages: The metal layer is thinned, the temperature rise is large, the polarization is large, and the cost is high. Its cost is more than four times higher than traditional aluminum foil according to the current process conditions.
