Life of Lithium battery cell= life of battery pack?

　　Traditional electric vehicles mainly use lead-acid batteries as the power core, leading the electric vehicle industry for decades. However, due to their short lifespan (200-300 cycles), large size, and low-capacity density, lead-acid batteries have almost been abandoned in the era of big energy. Lithium batteries are popular among people in the new energy industry for their small size, light weight, long life, and high energy density.

　　Lithium battery is a general term. If it is subdivided inward, it is usually divided according to physical shape, material system, and application field.

　　(1) According to the physical shape, lithium batteries are divided into three types: cylindrical, soft-packed, and square;

　　(2) According to the material system, lithium batteries are divided into: ternary (nickel/cobalt/manganese, NCM), lithium iron phosphate (LFP), lithium manganate, lithium cobalt oxide, lithium titanate, multiple composite lithium, etc.;

　　(3) Lithium batteries are divided into power type, power type, and energy type according to the application field;

　　The service life and safety of lithium batteries vary greatly with different material systems, and roughly follow the following rules.

　　Service life: lithium titanate>lithium iron phosphate>multiple composite lithium>ternary lithium>lithium manganate>lead acid

　　Safety: Lead acid>Lithium titanate>Lithium iron phosphate>Lithium manganate>Multiple composite lithium>Ternary lithium

　　Consumers generally think that the battery life is equal to the life of the battery pack system. This is incorrect:

　　1. The single cell has a large heat dissipation area and good heat dissipation. After forming the Pack system, the middle cell will not be able to dissipate heat well, which will decay too fast. The life of the battery pack system depends on the cell with the fastest attenuation. It can be seen that good thermal management and thermal equilibrium design are extremely important!

　　2. The battery cell cycle life promised by lithium battery manufacturers is based on test data at a specific temperature and specific charge and discharge rate, such as 0.2C charge/0.3C discharge at a normal temperature of 25°C. In actual use, the temperature can be as high as 45°C and as low as -20°C.

　　Charge it once under high temperature or low temperature conditions, the life will be attenuated by 2 to 5 times. How to control the charge-discharge and charge-discharge rate in high and low temperature environments is the key. The life of lithium batteries will be drastically reduced when using high-current chargers or vehicles with high-power controllers.

　　3. The service life of the battery pack system is also closely related to the performance of other components. Such as BMS protection board software and hardware, module integrity design, box vibration resistance, waterproof sealing, connector plug life and so on.

　　Finally, the use of high-quality, high-performance batteries is just a necessary condition for a high-quality battery pack system. To use good batteries to make a good battery pack system, there are too many links and factors to consider.

　　Lithium-ion battery (LIB) has become the main energy storage solution in modern social life. Among them, lithium iron phosphate batteries are a perfect substitute for lead-acid batteries, and are the first choice for grid-connected peak shaving, off-grid energy storage, photovoltaic energy storage, UPS, data center and other industries.

　　Solar power generation system with lithium battery energy storage system is a very promising clean energy.