Lithium battery structure and technology -Lithium - Ion Battery Equipment

Comparison of structural and technical characteristics of cylindrical, prismatic and pouch lithium batteries -Lithium - Ion Battery Equipment

Comparison of structural and technical characteristics of cylindrical, prismatic and pouch lithium-ion batteries

There are currently three mainstream lithium-ion battery packaging methods: cylindrical, square and soft packaging. Different packaging structures mean different characteristics, and each has its own advantages and disadvantages.

1. Circular lithium-ion battery

Cycle refers to the cylindrical lithium-ion battery. The first cylindrical lithium-ion battery was invented by Japan's Sony Corporation in 1992. Because cylindrical lithium-ion batteries were long before the 1850s, the market penetration rate is very high. When choosing a suitable mature winding process for cylindrical lithium-ion batteries, the degree of automation is high, the product quality is stable, and the capital is relatively low. There are many types of cylindrical lithium-ion batteries, such as 14650, 17490, 18650, 21700, 26650, etc. Cylindrical lithium-ion batteries are popular among Japanese and Korean lithium-ion battery companies.(Lithium - Ion Battery Equipment)

As the electric vehicle market further expands and cruising range requirements continue to increase, automobile manufacturers have put forward higher requirements for power lithium batteries in terms of energy density, manufacturing cost, cycle life and additional product attributes. On the premise that there is no major breakthrough in the field of raw data, appropriately increasing the volume of cylindrical batteries to obtain larger battery capacity has become a direction to be explored. Currently, Tesla has begun mass production of 21,700 batteries and plans to use them in Tesla Model 3 sedans.

2. Square lithium-ion battery

Square lithium-ion batteries, often called aluminum or steel square battery cases, square cell penetration is very high in our country. With the rise of automotive power lithium batteries in recent years, the life journey battery capacity has become increasingly prominent. Domestic power lithium batteries Manufacturers choose mainly aluminum square batteries with high energy density because the cell structure is relatively short and square unlike cylindrical batteries. They are made of high-strength stainless steel and have accessories such as explosion-proof safety valves, so the entire accessory assembly must be Light and relatively high energy density. There are two different processes for prismatic batteries: winding and lamination.

But because prismatic lithium-ion batteries can be customized according to the size of the product, there are thousands of different types on the market, and because there are so many types, it is difficult to unify the process. There is no problem with the use of prismatic batteries in general electronic products, but more than a series of parallel industrial equipment products, the production of standardized cylindrical lithium-ion batteries is fully utilized, so the production process ensures that it is easier to find replacement batteries in the future.

3. Soft pack lithium-ion battery

The key data used in soft-packed lithium-ion batteries are positive electrode data, negative electrode data and separator. The difference between steel and traditional aluminum lithium-ion batteries is not big. The biggest difference is the data of soft-packed lithium-ion batteries (aluminum-plastic composite film), which is the most important In soft-pack lithium-ion batteries, the data is the most technically difficult. Flexible packaging information is usually divided into three layers, namely the outer resistance layer (generally an outer protective layer composed of nylon BOPA or PET), the penetration resistance layer (aluminum foil middle layer) and the inner layer (multifunctional high barrier layer).

Soft pack battery packaging materials and structures have a series of advantages, electric zhijia public summary number, for example, good safety features, soft pack battery selection structure of aluminum plastic film packaging, safety issues attack, soft pack batteries usually break, and Instead of exploding like steel or aluminum shell batteries; light weight, soft pack batteries are 40% lighter than steel lithium-ion batteries of the same capacity and 20% lighter than aluminum lithium-ion batteries; the internal resistance is very small. The internal resistance of a battery is smaller than that of a lithium-ion battery. It has good cycle function, which makes the cycle life of the soft-pack battery longer. The attenuation of 100 cycles is 4%~7% smaller than that of the aluminum case. The design is flexible, the shape can be changed to any shape, it can be made thinner, and it can be customized according to customer needs to develop new batteries. The disadvantages of soft-pack batteries are poor consistency, higher cost, and short-term leakage. The high cost can be dealt with through large-scale production, and leakage can be dealt with by improving the quality of the aluminum-plastic film.

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