History #

The 21700 battery size was introduced to the market in 2016, when Panasonic released the first commercially available 21700 battery. This was a significant advancement in the lithium-ion battery market, as it was the first battery of this size to offer a capacity of up to 3,500 mAh, a significant improvement over previous battery sizes.

Since then, other battery manufacturers have followed suit, with Sony, LG, Samsung, and many others releasing their own 21700 batteries. These batteries are now widely used in a variety of applications, from electric vehicles to consumer electronics.

Typical Chemistry #

The 21700 battery size typically uses lithium-ion chemistry, although some manufacturers have released 21700 batteries with other chemistries, such as lithium-polymer and nickel-metal-hydride.

The most common type of lithium-ion chemistry used in 21700 batteries is the NMC (lithium-nickel-manganese-cobalt) chemistry. This chemistry offers a high energy density, low self-discharge rate, and good cycle life.

Other chemistries, such as lithium iron phosphate (LFP) and lithium titanate (LTO), are also available in 21700 batteries. These chemistries offer higher cycle life and lower self-discharge rates than NMC, but typically have lower energy densities.

Typical Use #

The 21700 battery size is widely used in a variety of applications, from electric vehicles to consumer electronics.

In electric vehicles, 21700 batteries are typically used in the form of battery packs, which are composed of multiple 21700 cells connected in series and/or parallel. These battery packs provide the necessary voltage and capacity for powering electric vehicles.

In consumer electronics, 21700 batteries are used in a variety of devices, such as laptops, tablets, and power banks. They provide the necessary power to run these devices, and can be easily replaced when needed.

Design #

The 21700 battery size is designed to be versatile and easy to use. It is slightly larger than the 18650 battery size, but still small enough to be used in a variety of applications.

The 21700 battery size also features a variety of safety features, such as overcharge protection, overdischarge protection, and short-circuit protection. These features help to ensure that the battery is safe to use, and prevents damage to the device it is powering.

The 21700 battery size is also designed to be lightweight and durable. This allows it to be used in a variety of applications, from electric vehicles to consumer electronics. The battery is also designed to be easily replaceable, making it convenient for users to replace their batteries when needed.