PET positive electrode composite aluminum foil

Enhancing battery safety

Thermal runaway protection: The PET layer acts as an insulating support. When there is an internal short circuit or thermal runaway in the battery, it can block the current flow and prevent metal spires from piercing the separator, thereby reducing the risks of combustion and explosion.

Puncture and fuse mechanism: When the battery is punctured, the PET layer is heated and melts, breaking the circuit and preventing direct contact between the positive and negative electrodes, which can avoid thermal runaway.

Increasing energy density

Lightweight design: The density of PET (1.38g/cm³) is much lower than that of aluminum (2.7g/cm³). Replacing part of the aluminum layer with PET can significantly reduce the mass of the current collector. According to calculations, the composite aluminum foil can reduce the overall battery mass by approximately 50%-80%, thereby increasing the quality energy density by 5%-10%.

Thickness optimization: The thickness of the composite structure is reduced by 25%-40% compared to traditional aluminum foil, providing more space for the active materials and further enhancing the volumetric energy density.

Extending cycle life

Buffering volume changes: The PET layer can absorb the expansion-contraction stress of the positive electrode material during charging and discharging, reducing the fatigue fracture of the aluminum layer and extending the battery cycle life.

Inhibiting lithium dendrites: In solid-state batteries, the PET layer can inhibit the growth of lithium dendrites and improve the stability of the solid-solid interface.