Aluminum Plastic Film: Enhancing Lithium Battery Packaging

Aluminum plastic film stands as a vital component in the upstream packaging of the lithium battery industry, constituting a significant portion (10-20%) of the total material cost for pouch batteries. Primarily used in soft pack batteries and blade batteries, this composite flexible packaging material plays a crucial role in safeguarding internal electrodes and isolating the external environment.

Understanding Aluminum Plastic Film Structure and Properties:

1. Structure: The aluminum plastic film comprises three layers held together by adhesives to ensure requisite properties. These layers include the outer resistance layer, the barrier layer (usually aluminum foil), and the heat-sealing layer.

2. Properties:

• Puncture resistance, crucial for protecting internal components.
• High barrier properties against oxygen and moisture.
• Resistance to electrolyte, crucial for battery performance and safety.
• High-temperature resistance to maintain structural integrity.
• Insulation properties for electrical safety.
• Cold stamping formability for manufacturing flexibility.

3. Production Process:

• Dry Method:

Direct bonding of aluminum foil and polypropylene film (CPP) using adhesive.

Ensures good drawing performance and appearance.

Suitable for high-capacity soft-pack consumer batteries and power batteries.

Requires high-quality CPP with superior barrier properties.

• Thermal Method:

Bonding of aluminum foil and CPP through modified polyethylene (MPP), followed by thermal synthesis.

Offers good electrolyte and water resistance properties.

Suitable for consumer batteries with low capacity requirements.

Long-term high-temperature baking may affect aluminum foil integrity.

4. Advancements in Production and Localization:

Recent technological progress and increased production capacity by related enterprises have facilitated the localization of aluminum plastic film production. Despite the challenges posed by the complexity of production technology, ongoing efforts have led to significant strides in achieving self-reliance within the lithium battery industry.

In summary, aluminum plastic film plays a critical role in enhancing the safety, performance, and efficiency of lithium batteries. With continuous advancements in production technology and localization efforts, the lithium battery industry is poised for further growth and innovation in battery packaging.