21700 battery is one of the most popular and commonly found cells in the battery pack in electric vehicles, battery-powered construction equipment, portable power cutting/ drilling tools, the emergency torch, flashlight, etc. after 18650 battery cells. Here we have listed all the possible technical 21700 battery specifications that can be very useful in executing any technical design of your product or gadgets.
What is a 21700 battery? and specifications
The 21700 battery is a Li-ion battery named after its 21mm × 70mm cylindrical size (diameter × height). When compared to AA size and 18650 type cells, their height and diameter both are larger. They are not replacements for AA or AAA or 18650 size cells.
The 21700 battery type is popular in rechargeable and high current draining devices considering its higher degree of capabilities like 1000+ charge cycle and higher energy density.
With the 21700 Li-ion battery due to its higher energy density and power output, we are able to manufacture and use cordless power tools like portable drill machines, long-range electric vehicles, etc.
This was just an imagination a few years back to have portable power tools in the field of utility and construction like cutting and drilling tools etc.
It is good to see 21700 lithium cells gives the ability to compete and provide the replacement option to the corded tools in all-around areas by providing longer run time.
Its safety property along with its high output current and energy capacity makes this battery popular among tech industries.
The 21700 battery specs includes its properties like the voltage, capacity, charge-discharge cycle, output current, output voltage, and so on.
This is a generalized specs of 21700 Li-ion battery, only properties marked with the remark of “Standard/(std.)” are common to all 21700 batteries else not.
This is to note that other properties such as capacity (mAh), charge-discharge cycle are subjected to independent technologies. All the 21700 specs are listed in the table in detail.
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21700 battery specification table:
|21 ✖ 70 mm
|Standard (dd ✖ hh)
|3500- 5600 mAh
|2.5- 4.2 volt
|2 - 2.5 volts
|Check respective datasheet
|55gms to 75gms
|Depends on capacity & technology
(Energy per cell)
|Charge discharge cycle
|500 to 2000
|In number ()
|Continuous discharge current
|20- 35 amps
|Optimum /Minimum charging time
|2.5 hrs to 3.5 hrs
|CC and CV
|5 volt max
|check C rating*
|check C rating*
|6 - 10 %
Always check the datasheet as above information is a general specs.
21700 battery size / dimension:
The Standard 21700 battery size is 21 ✖ 70mm.
The 21700 battery length is 70mm.
The diameter of the 21700 battery is 21mm.
To be more precise, it has an approximate length of 70mm and an approximate diameter is 21mm but technically 21700 cell size is allowed with some tolerance in length and diameter.
Thus you could find specifications written as (say) 21 ± 0.41mm ✖ 70 ± 0.25mm on the datasheet and features of the li-ion cell.
Just remember 21 ✖ 70mm as a standard size, the remaining things will be taken care of by designers and manufacturers of devices and batteries.
21700 battery data sheet:
The data sheet specification describes the technical parameters and standard tested output of each for the particular component or module.
Here we have discussed the 21700 battery datasheet, on paper its a li-ion rechargeable cell supplied by various electronics manufacturing companies.
There are hundreds of 21700 battery datasheets available belonging to a different models of 21700 batteries, there are lots of different models available varying in current rating and charge holding capacity. Also top manufacturer have their cell model with inbuilt overcharge protection and short circuit protection circuit to prevent damage to the cell as well as device in which it is installed.
List of top best 21700 battery manufacturing companies along with the datasheets :
One of the popular samsung battery under the name samsung 21700 30T. Its actual Model No. is INR21700-30T
One of the popular samsung battery under the name samsung 21700 40T. Its actual Model No. is INR21700-40T
Model No. 21700M50
From their data sheet you can analyse and study what parameters are to be considered. All these parameter to be keep in mind before, while and after manufacturing, testing and launching the a final product in the market.
We have discussed the 18650 specs and properties in detail here.