What material is used for the battery casing?

       The battery shell acts as a critical protective armor for battery cells. It encapsulates internal components, isolates external dust, moisture and impact, and fundamentally determines the battery's safety, heat dissipation efficiency and service life. Selecting the right shell material is essential for battery performance optimization. In the current industry, battery housing materials are mainly divided into three categories: metal materials, engineering plastics, and advanced composite materials, each serving distinct application scenarios.
　　Metal materials are the mainstream choice for power batteries and large-capacity lithium batteries, primarily including aluminum alloy and stainless steel. Aluminum alloys such as 3003 and 5052 series are widely favored for their lightweight structure, excellent thermal conductivity and superior machinability. They efficiently dissipate heat generated during battery operation, greatly reducing the risk of thermal runaway. In addition, aluminum alloy shells feature high toughness and tight sealing. With precision stamping and built-in explosion-proof valves, they release internal pressure in extreme conditions, ensuring high safety. These properties make them ideal for new energy vehicle batteries and large-scale energy storage systems. Compared with aluminum alloy, stainless steel delivers higher structural strength and corrosion resistance. It provides outstanding impact resistance and stability, suitable for industrial energy storage batteries and coin cells. The main drawback is its heavier weight, limiting its application in lightweight-focused scenarios.
　　Engineering plastics dominate small consumer battery housings, with common materials including ABS, PVC and polypropylene. The core advantages of plastic shells are low cost, strong plasticity and excellent insulation. They can be molded into diverse complex shapes to fit compact device designs and effectively prevent electric leakage and short circuits. Lightweight and flexible, these plastic shells are widely applied in small-power batteries for Bluetooth earphones, remote controls, portable digital devices and household lead-acid batteries. However, plastic materials have obvious limitations. They possess poor heat resistance and thermal conductivity, prone to aging and deformation under high temperatures. Their weak anti-collision performance makes them unable to adapt to high-power and high-load power battery environments.
　　With the rapid upgrading of new energy technologies, advanced composite materials represented by SMC have gradually become emerging battery shell solutions. Composites integrate the strengths of metal and plastic materials, featuring light weight, excellent insulation, superior corrosion resistance and upgraded high-temperature resistance. They are widely used in high-end energy storage equipment and new energy vehicle battery packs, becoming a key development trend for future battery housing manufacturing.
　　In summary, battery shell material selection depends on actual usage requirements. Low-power consumer batteries prioritize cost-effective engineering plastics; power and energy storage batteries adopt lightweight and high-safety aluminum alloys; and industrial special batteries rely on high-strength stainless steel. The diversified matching of materials ensures stable and safe operation of various batteries in different working environments.