Lithium-ion 21700 batteries are part of high-drain devices that provide a voltage range of 3.6 to 3.7 volts and are used where constant voltage is needed and also provide a low self-discharge rate and larger charging and discharging cycles. 21700 lithium rechargeable batteries have different chemistry, battery capacity, and maximum pulse for different types. In this post, we will cover detailed features and types of 21700 batteries. So let’s get started with Introduction to 21700 Battery.
What is a 21700 battery?
- The 21700 battery is a rechargeable battery that comes with lithium-ion chemistry. The dimensions of the battery are 21 mm in diameter, and the length is 70 mm.
- This battery was first used for different electric vehicles such as electric scooters and Tesla. Now it is part of vaping and flashlights.
- The 21700 battery is the main part of high-drain devices that need high-capacity battery packs, such as electric bikes, high-end toys, cordless tools, and flashlights.
- The battery capacity is in the range of 3000 to 500 mAh according to model, design, and chemistry.
- Battery charging and discharging current based on either battery being high or low drain.
- High-drain 21700 battery has a high current of more than 30 amps without any bad effect on battery working life, and low-drain 21700 battery is not discharged with more than 5 amps current.
21700 Battery Chemistry
IMR 21700 batteries
- This battery comes with Lithium Manganese Oxide chemistry, and the nominal voltage for the battery is 3.6 to 3.7 volts per cell, and the high recommended charging voltage for the battery is 4.2 volts. The IMR battery comes with a small capacity and has features for providing larger current values.
INR 21700 batteries
- This battery comes with lithium manganese nickel chemistry and is like an IMR battery and has a high current value and low capacity.
IFR 21700 batteries
- This battery has lithium iron phosphate chemistry; a nominal voltage is 3.2 to 3.3 volts per cell, and the recommended highest voltage is 3.5 to 3.6 volts. This battery is known as a safe battery and is part of electric bikes and scooters.
ICR 21700 batteries
- It comes with lithium cobalt oxide, and the voltage for the battery is 3.6 to 3.7 volts, and the recommended voltae high value is 4.2 volts. It has high capacity, and the current is low.
18650 vs 21700 vs 32650 Batteries
- The 18650 battery dimensions are 18 mm in diameter and 54 mm in length, and the capacity is about 1800 mAh to 3500 mAh. The 21700 battery dimensions are 21mm x 70mm, and the capacity range is 3000mAh to over 5000mAh.
- 32650 battery dimensions are 32mm x 65mm and have a high capacity of more than 6000 mAh and provide high drain uses.
18650 Battery:
- • 18mm diameter x 65mm height
- Nominal Voltage: around 3.7V
- Capacity: 1200 mAh to 3500 mAh
21700 Battery:
- Dimensions: 21 mm diameter x 70 mm height
- Nominal Voltage: 3.7V
- Capacity: 3000 mAh to over 5000 mAh
32650 Battery:
- Dimensions: 32 mm diameter x 65 mm height
- Nominal Voltage: 3.2V to 3.7V
- Capacity: 5000 mAh to more than 12000 mAh
| Battery Type | Dimensions (mm) | Nominal Voltage (V) | Capacity (mAh) |
| 18650 | 18 x 65 | 3.7 | 1200 to3500 |
| 21700 | 21 x 70 | 3.7 | 3000 – >5000 |
| 32650 | 32 x 65 | 3.2 to to 3.7 | 5000 – >12000 |
26650 vs. 21700 Batteries
The 26650 battery comes with a larger size and high capacity that is 4000 mAh to 5500 mAh. The 21700 battery is small in size and capacity in the range of 3000 mAh to 5000 mAh. Some other differences are as
Size:
- • The 26650 battery has a diameter of 26mm and a length of 65mm, and the 21700 battery diameter is 21mm and the length is 70mm. This difference defines their compatibility and uses.
Capacity:
- • The 26650 battery has a high capacity that is from 4000 mAh to 5500 mAh. 21700 battery capacity is 3,000mAh to 5,000mAh. Capacity has an effect on runtime and power supply features for the battery and provides reliable working performance.
Interchangeability:
- The 26650 and 21700 batteries have different sizes and capacities but can be exchanged for some applications. It is important to make sure that devices have compatible for the battery used.
18650 vs. 21170 Battery
| Features | 21700 Battery |
18650 Battery
|
| Nominal Voltage | 3.6V | 3.6V |
| Nominal Capacity | 4000mAh |
3000mAh
|
| Capacity | 3500-4000mAh |
2500-3000mAh
|
| Operating Voltage | 2.5-4.2V | 2.5-4.2V |
| Cut-off Voltage | 2.5V | 2.5V |
| Charging Voltage | 4.2V | 4.2V |
| Charging Current | 1-4A | 0.5-2A |
| Charging Time | 3-4 hours |
2-3 hours
|
| Charge/Discharge Cycles | 1000 |
800
|
| Charging Method | (Constant Current/Constant Voltage) |
CC/CV
|
21700 cells Types
| Type | 21700-4Ah | 21700-4.5Ah | 21700-4.8Ah | 21700-5Ah |
| Voltage | 3.7V | 3.7V | 3.7V | 3.7V |
| Capacity | 4000mah | 4500mah | 4800mah | 5000mah |
| Material | NCM | NCM | NCM | NCM |
Are 21700 batteries safe to use?
- The 21700 battery is safe to use as compared to other types of lithium-ion batteries. This battery comes with a built-in battery management system that properly checks the conditions of the battery and avoids any issue creation.
What is the working life of the 21700 battery?
- The 21700 battery recharged after 3 to 6 months. It is compatible with some hundred charging or discharging cycles down to 100 percent DOD.
Are 21700 batteries better than 18650?
- Normally 21700 battery is a larger size as compared to an 18650 battery has high capacity and is compatible with high charging/discharging currents.
- High-discharge 18650 battery has a strong current as compared to low-discharge 21700 battery. The low-discharge 21700 battery has a lower capacity than the low-discharge 18650 battery and a higher capacity than the high-discharge 18650 battery.
How much does a 21700 battery cost?
- The cost of the battery is based on chemistry, manufacturers, charging/discharging cycles, etc.
Do 21700 batteries fit 18650?
- The 21700 battery is not used for the 18650 battery compartment, but the 18650 battery is also not used for the 21700 battery compartment. Use the 18650 to 21700 battery adapter and help users to put the 18650 battery in the 21700 battery compartments.
Can an 18650 charger charge 21700?
- Some types of 18650 battery chargers get both larger and smaller batteries compared to 18650 batteries.
How to charge a 21700 battery?
- The simple technique is to use lithium battery chargers that are compatible with 21700 batteries. Some 21700 batteries have micro USB charging ports and help users to charge directly from USB points on desktops and laptops.
How much is the 21700 battery size?
- The dimensions for the battery are (D x H) 21 x 70 mm.
What are 21700 batteries used for?
The 21700 battery is used for electric tools, electric bikes, scooters, etc. The lithium iron phosphate 21700 battery comes with 3.2 volts and is not compatible with strong discharge current. LiFePO4 provides a larger number of charging or discharging cycles and has a low self-discharge rate.
The high drain 3.6 to 3.7 volts are common for flashlights.
What are the advantages and disadvantages of 21700 batteries?
Advantages
- 21700 comes with many features, such as high energy density and storage of high energy for a small size. It results in a longer time for devices. With that, they are lower cost than other batteries and easy to install. The design of the 21700 battery helps to make battery packs and easy configuration.
Disadvantages
- Some disadvantages are that its larger than other batteries can restrict its use for some devices and needs changes in fitment. The 21700 battery also has high internal resistance which affects high current uses and reduces efficiency.
What is the difference between 18650 and 21700 lithium batteries?
- The basic difference between 18650 and 21700 lithium batteries is size and capacity. 21700 battery has a larger diameter and capacity than the 18650 battery and provides high energy density and good performance.
What is the difference between 18650 and 21700, 46800?
- The basic differences for these three batteries are their size, capacity, and working performance. The 18650 battery is a small size and has a lower capacity than the 21700 and 46800 batteries.
- • The 21700 battery comes with a larger diameter and capacity as compared to the 18650 battery, and the 46800 battery has a larger size and provides high capacity and power.
What are the drawbacks of 18650 batteries?
- The main disadvantages of the 18650 battery are its low capacity and energy density compared to larger battery types such as 21700 or 46800.
Is 21700 better than 18650?
- The 21700 battery has advantages over the 18650 battery, such as high capacity, high current handling features, and good density features. The battery is based on the type of devices where the battery is used.
Why are 21700s lower cost than 18650s?
- The cost of 21700 batteries and 18650 batteries is based on brands, manufacturing, and application requirements.
Can we replace 18650 with 21700?
- In some applications, we can replace the 18650 battery with a 21700 battery, especially for devices that can handle the larger size 21700 battery. It is important to check voltage, capacity, and support for charging and circuits.
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