Soft pack battery
The so-called soft pack battery - the main difference lies in the packaging material of the lithium battery shell, which uses aluminum-plastic composite film (referred to as aluminum-plastic film). The positive electrode, negative electrode, electrolyte, separator and other battery materials of other lithium batteries are also similar.
The packaging of the entire lithium battery shell, if used to classify: first generation, steel shell; Second generation, aluminum shell; Third generation, soft pack aluminum-plastic film.
Steel shell battery, aluminum shell battery
The biggest harm of lithium batteries is the possible instability of battery materials and other unexpected factors, which can cause uncontrolled heating and invisible accumulation of gas inside the battery. Steel or aluminum shells form a fixed space that limits gas expansion, leading to battery explosions.
In this situation, battery soft packaging emerged. The aluminum plastic film used for soft packaging batteries is relatively soft and deformable. In the event of a safety hazard, at most it will only burst due to inflation.
In addition to the soft pack lithium battery, it brings relative safety. Compared to steel shell packaging, it also saves the weight, volume, and reduces internal resistance of lithium batteries. This has great benefits for improving the quality density or volume density of lithium batteries. At the same time, soft pack batteries also have the characteristics of low cycle loss and diverse design and packaging shapes.
Exactly, based on the advantage of lithium battery soft packs. Greatly attracting the attention and industrialization of various countries.
Among them, lithium-ion battery soft packaging, Korean LG is at the forefront!
"According to foreign media reports on February 28th, South Korean automaker Hyundai has officially released the pure electric SUV - Kona EV, which has a maximum power of 150 kW and a range of 470 kilometers."
And the power battery used in this electric vehicle is the LG811 ternary lithium battery produced by LG Chem in South Korea. More importantly, the world's first soft pack ternary lithium battery used in electric vehicle power batteries! It uses NCM811 high energy density positive electrode material. Therefore, the production of LG811 high energy density soft pack power batteries has become a reality.
Correspondingly, NAC materials are used. At present, the Japanese Panasonic 18650B and Tesla 21700 batteries, which represent the highest energy density level of individual batteries in the world and are used in Tesla Model x Model 3 power batteries, still use battery steel shell packaging.
Tesla 21700 battery
Mainstream domestic lithium battery soft pack companies include Funeng Technology, Guoneng Battery, Wanxiang A123, and other manufacturers. Planned potential production capacity, strong. However, currently, the energy density of mainstream NCM523/622 materials and power lithium batteries in China is mostly between 160~230wh/kg. Using NCM811 and Tesla NCA2170 with LG, the energy density is already around 300wh/kg. The gap is obvious.
At the same time, the high-end aluminum-plastic film required for the battery pouch has been broken by Gong from Japan and South Korea. And the domestic production rate of aluminum-plastic film is only 5%. Moreover, domestically produced aluminum-plastic films are mostly used in the 3C electronic consumer lithium battery market. More than 90% of aluminum-plastic films are yet to be imported. This is a space that needs to be greatly improved by domestic enterprises.
The difficulty of aluminum-plastic film technology lies in effectively resisting the swelling, dissolution, and absorption of electrolyte. It is also required to ensure strict isolation of oxygen and moisture. The technical difficulty is even greater than that of the positive electrode, negative electrode, electrolyte, and diaphragm technology links! Soft pack lithium battery, sealed with thermal encapsulation; The metal shell is sealed with laser welding.
Not long after, the emergence of safer and higher energy density solid-state batteries became possible. The battery casing is soft and the integration of the two can further enhance the safety and energy density of lithium batteries!