21700 battery is the model of the cylindrical battery, specifically: 21 - the outer diameter of the cylindrical battery is 21mm; 700 - the height of the cylindrical battery is 70.0mm. The 21700 battery is a new model developed to meet the requirements of electric vehicles for longer mileage and to improve the effective utilization of vehicle battery space.

The 21700 battery has four significant advantages:
1. The battery capacity is increased by 35%. The battery capacity of a single battery can reach 3 to 4.8 Ah, a substantial increase of 35%.
2. The energy density of the battery system is increased by about 20%.
3. The cost of the system is expected to drop by around 9%.
4. The weight of the system is expected to drop by about 10%. The overall volume of the 21700 battery is larger than that of the 18650 battery. With the increase of the cell capacity, the energy density of the cell is higher, so the number of battery cells required under the same energy can be reduced by about 1/3, which will reduce the difficulty of system management and also reduce the The number of metal structural parts and electrical accessories used in the battery pack further reduces the weight of the battery.