Case analysis and material selection recommendation of thermal interface materials in cylindrical, square, and soft pack power batteries

Cylindrical battery: mature production process, high product stability rate

At present, the main models of cylindrical batteries include: 14650, 17490, 18650, 21700, 26500, etc. The production process of cylindrical lithium batteries is mature, the PACK cost is low, the battery product yield and the consistency of the battery pack are high. Due to the large heat dissipation area of the battery pack, its heat dissipation performance is better than that of square batteries. Cylindrical batteries are easy to combine in various forms and are suitable for the full layout of electric vehicle space design. However, cylindrical batteries are generally packaged in steel or aluminum shells, which are relatively heavy and have lower specific energy. At present, there are mature production enterprises in China, Japan, South Korea, the United States, etc., such as SANYO SONY、LG、 Wanxiang A123, etc.

Square hard shell battery: Due to excessive weight, it is difficult to unify the product

The shell of square hard shell batteries is mostly made of materials such as aluminum alloy and stainless steel, and the interior adopts winding or laminated technology, which provides better protection for the battery cells than aluminum-plastic film batteries (i.e. soft pack batteries). The safety of the battery cells has also been greatly improved compared to cylindrical batteries. At present, companies producing square hard shell batteries include Guoxuan High tech, Samsung SDI, Lishen, Ningde Times, etc.

Soft pack batteries: expected market share to exceed 50% in the future

The key materials used in soft pack lithium batteries - positive electrode materials, negative electrode materials, and separators - are not significantly different from traditional steel shell and aluminum shell lithium batteries, with the biggest difference being the soft pack material (aluminum-plastic composite film). Compared to square hard shell batteries, it has higher safety, and more importantly, it is lighter in weight, flexible in design, and can have any shape. It can be thinner and customized according to customer needs, and new battery cell models can be developed.