21700 cell 21v lithium battery

The 21700 battery is a cylindrical lithium-ion battery with a diameter of 21mm and a length of 70mm. It offers a nominal voltage of 3.7V and a capacity of up to 5,000mAh, making it a powerful and efficient energy source. Its energy density ranges between 250 Wh/kg and 300 Wh/kg, depending on the chemistry.

However, most 21700 cells are based on lithium-ion (Li-ion) technology, which is widely used across many types of rechargeable batteries due to its excellent energy density and long lifespan. There are several types of lithium-ion chemistries that could be used within the 21700 format:

Unprotected 21700 batteries: Lack built-in safety features and are generally used in battery packs with external battery management systems (BMS). 21700 batteries are widely used in: Electric vehicles, with companies like Tesla and other manufacturers using them in battery packs for improved energy storage and performance.

Energy Density: One of the primary reasons for the 21700 battery's growing popularity is its energy density. Offering approximately 20% more energy per unit volume than the 18650, it can store more power in the same space, enhancing the performance of your devices.·

The 21700 cell stands out due to its standardized dimensions of 21mm in diameter and 70mm in length. These measurements make it larger than the widely used 18650 cell, which measures 18mm by 65mm. This increase in size allows the 21700 to deliver higher energy storage and improved performance.

The 21700 battery utilizes advanced lithium-ion chemistry, which provides a balance between energy density, safety, and longevity. Depending on the specific chemistry, such as NMC or LCO, the energy density of the 21700 ranges from 250 Wh/kg to 300 Wh/kg.