The difference between cylindrical ternary lithium battery and square ternary lithium battery. Probably many people know that ternary lithium batteries have a variety of packaging forms, which are cylindrical, square and soft pack type. Cylindrical and square batteries generally use steel or aluminum as the shell, while soft pack lithium battery packaging material is aluminum plastic film. The following explains the difference between cylindrical ternary lithium battery and square ternary lithium battery.
The difference between cylindrical lithium battery and square lithium battery
Cylindrical batteries are mainly steel-cased cylindrical lithium iron phosphate batteries, which are characterized by high capacity, high output voltage, good charge and discharge cycle performance, stable output voltage, high current discharge, stable electrochemical performance, safe to use, wide operating temperature range, and friendly to the environment. It is widely used in solar lamps and lanterns, lawn lamps and lanterns, backup energy, electric tools, and toy models.
At present, only cylindrical ternary lithium batteries have consistency in manufacturing standards, for example, the cylindrical batteries we are familiar with are divided into 14650, 18650, 21700 and other models, which many people think is a battery type, but it only represents the size standard of cylindrical batteries. Take 18650 type as an example, it is the most mature cylindrical battery standard, while 21700 type is progressing through continuous technical progress, it is possible to replace 18650 type as the preferred cylindrical battery product for new energy vehicles in the next.
The square lithium battery is more malleable and can be customized according to the specific needs of the product. Therefore, it leads to different sizes, and currently there is no clear standard division like cylindrical batteries, regardless of manufacturing process or application standards. However, because of its high flexibility, it was used in early new energy vehicles for a long time, and car companies can customize the size of the square battery according to the needs of the model, without the restrictions of the cylindrical battery standard.
1. Energy density ratio
Energy density ratio refers to the capacity of the unit fraction of lithium batteries. The energy density ratio can be 215WH/Kg for cylindrical monoblocks and 205WH/Kg for square monoblocks according to 50AH, which is about 129WH/Kg for 18650 battery pack system and 143WH/Kg for square lithium battery pack system.
2. Multiplier nature
Charge and discharge rate = charge and discharge current / rated capacity, the higher the charge and discharge rate, the faster the charging speed of lithium battery support. Domestic mainstream level energy core 18650 is about 1C, the square can reach 1.5 ≤ 2C (need to deal with thermal management), there is still a distance from the policy goal of 3C. However, in order to achieve the established 3C goal, the square manufacturing process is entirely possible to become more and more perfect.
3. Consistency
The greater the number of cells, the more difficult it is to manipulate consistency. Assuming that the defective rate of a cell is 1 in 100,000, a round cell battery pack consists of 7000 18650 cells, and a square cell battery pack consists of 250 cells, a battery pack without defective products is considered qualified. The qualified rate of round cell battery pack is 0.99999^7000=93.2%, and the qualified rate of square cell battery pack is 0.99999^245=99.7%. This shows that the use of a single larger capacity, less number of square cells battery pack is more conducive to control consistency.
The above is the difference between cylindrical ternary lithium battery and square ternary lithium battery. In general, the cylindrical and square two package types of batteries have their own advantages and shortcomings, each battery has its own dominant field, with the introduction of the new subsidy policy for new energy vehicles, the system energy density of the battery has become an important assessment index.
If you have any demands in batteries, please feel free to contact info@manlybattery.com
