What is a 21700 lithium-ion battery?
2023-09-27
The meaning of 21700 battery actually usually refers to a cylindrical battery with an outer diameter of 21mm and a height of 70.0mm.
Using the same materials, the 21700 battery has a capacity ratio that is 35% higher than the classic 18650 cylindrical lithium-ion battery.
Speaking of the emergence of 21700 batteries, Tesla cannot be ignored. The 21700 battery was originally developed by Panasonic for the American company Tesla. At the investor conference on January 4, 2017, Tesla announced that it would begin mass production of the new 21700 battery cells jointly developed with Panasonic and would be produced at the Gigafactory. Tesla CEO Musk said that the new 21700 battery is the battery with the highest energy density and lowest cost in the world, and the price will be more approachable.
On July 28, 2017, the first batch of Tesla Model 3 equipped with 21700 batteries was delivered, becoming the world's first 21700 pure electric new energy vehicle, with a minimum price of US$35,000. The emergence of 21700 batteries makes Model 3 Tesla’s most affordable model to date. It can be said that Tesla Model 3 fully empowers 21700 batteries and has entered a new stage of cylindrical battery capacity improvement.
Advantage
(1) Lighter weight and larger vehicle space:
The specific energy of the cell is higher, so the number of cells required for the same energy can be reduced by 1/3, and the difficulty of system management can be greatly reduced. The number of metal structures is reduced and the electrical accessories used in the battery can be greatly reduced, further reducing the need for lithium Battery weight. The specific energy of the vehicle will be partially increased.
(2) Better cost performance:
After choosing 21700, the number of batteries will be greatly reduced. While greatly reducing the difficulty of system management, the number of metal structural parts and conductive connectors used in the battery pack will also be reduced in proportion. Tesla’s Pack project cost accounts for approximately 24% of the total system project cost, and the cost reduction of the battery Pack project is expected to be relatively optimistic.
(3) The energy density of the battery system is increased by about 20%.
Data disclosed by Tesla shows that the energy density of the 18650 battery system used in the early days was about 250Wh/kg. The energy density of the 21700 battery system produced later was about 300Wh/kg. The volume energy density of the 21700 battery was nearly 20% higher than the original 18650. %.
(4) High discharge current: 21700 batteries can generally provide higher discharge current, which makes them suitable for applications requiring high power output, such as electric vehicles and power tools.
(5) Wide application: 21700 batteries are widely used in electric vehicles, electric bicycles, energy storage systems, handheld electronic devices, power tools, flashlights, aerospace and other fields.
What is an 18650 battery?
