18650 vs. 21700: What Difference is between them?

18650 Overview

A  lithium-ion battery is a 18650 battery. The name is derived from the battery's dimensions: 18mm x 65mm. That's about the size of an AA battery. The 18650 battery has a 3.6v voltage and a capacity of 2600mAh to 3500mAh (mili-amp-hours).

21170 Overview

The cylindrical 21700 battery has a diameter of 21mm and a height of 70.0mm. It has the best energy density and lowest cost battery in the world at the moment, and it is cost-effective.

18650 Characteristic

• Large capacity: A lithium battery has a capacity of at least 1200mah, if not 3600mah, but the ordinary battery cell has a capacity of just 500mah.

• High energy storage efficiency and stability: It can still sustain full performance output at temperatures below 70°, and there is usually a protection circuit within to keep the battery from burning out.

• No memory effect: There is no need to discharge all leftover power before charging, and it may be charged and discharged at any moment, making it comfortable to use.

• High charge and discharge cycle life: Lithium batteries have tens of thousands of cycles and high-temperature resistance.

• Environmental safeguards, no hazardous substances: Non-toxic, non-polluting, and  RoHS quality certified.

21170 Characteristic

• Because the positive electrode has been converted to nickel, the performance is unaffected, the consistency is good, and it may be used immediately as a battery pack.

• Lithium-ion Rechargeable Cell

• Size: Diameter: 21mm, Length: 70mm

• Weight: around 65g

• Rated voltage: 3.6V

• Standard capacity: 4800mAh

• Internal resistance: approximately 13 milliohms

• Charging voltage: 4.2V

• Discharge cut-off voltage: 2.5V

• Discharge current: 10A (15-20A can be discharged instantaneously).

• Flashlights, scooters, LED lights, miner's lamps, lighting products, power banks, mobile power supplies, backup power supplies, computers, mobile devices, automobiles, bicycles, communications, medical, energy storage, solar energy, and so on.

18650 Advantage

1) Large storage capacity

The capacity of a 18650 battery ranges from 1200mah to 3600mah, while the capacity of a standard battery is just about 800mah. When paired with a 18650 battery pack, it can easily exceed 5000mah.

2) Prolonged Life

The 18650 battery has a long service life, with a cycle life of more than 500 times during typical operation, which is more than double that of standard batteries.

4) Very High Voltage

The voltage of a 18650 lithium battery is typically 3.6V, 3.8V, or 4.2V, which is significantly higher than the 1.2V voltage of nickel-cadmium or nickel-metal hydride batteries.

5) There is no memory effect.

It is not necessary to drain the remaining power before charging, making it more convenient to use.

6)Internal Resistance Is Low

The internal resistance of the polymer battery is lower than that of the general liquid battery, and the internal resistance of the domestic polymer battery can be as low as 35m, which significantly reduces self-consumption of the battery and increases the standby life of the mobile phone. This polymer lithium battery with a high discharge current is perfect for remote control models and has emerged as the most promising replacement for nickel-metal hydride batteries.

7) It can be connected in series or parallel to make a lithium battery pack with 18650 cells.

8) Broad Applicability

Notebook computers, walkie-talkies, portable DVD players, instrumentation, audio equipment, model aeroplanes, toys, video cameras, digital cameras, and other electronic devices can all use 18650 batteries.

21170 Advantage

1) The 21700 type battery has a better energy density than the well-known 18650 type battery. After grouping, the number of single cells in use can be considerably decreased, as can the cost. A 18650 battery has a capacity of roughly 2600-3600 mAh, whereas a 21700 battery has a capacity of more than 4000 mAh, and even 5000mAh has surfaced on the market. Furthermore, a bigger capacity is becoming increasingly useful for extending the battery life of current devices.

2) The rechargeable battery's single volume has been raised by 35%. Using the  Tesla  21700 rechargeable battery as an example, a single battery's energy can be enhanced by 34.8ah, a 35% increase.

3) It is expected that the net weight of the system software will be lowered by 10%. The total capacity exceeds 21700. The total number of batteries required under the same kinetic energy can be reduced by about 1/3 with an increase in a single volume and an increase in single energy ratio, and the total number of metal components and electrical components selected for the battery pack can reduce the difficulty of managing information systems coefficient. After changing the SDI (Samsung Digital Interface) to the new 21700 rechargeable battery, the system software discovered that the net weight was lowered by 10% over the current battery.

Many people question what the main difference is between a 21700 battery and a 18650 battery. Physically, the difference is simple; the size is the only difference. The 21700 battery is slightly larger than the 18650 battery. Both are available in flat top and button top styles. One, though, is smaller than the other. Because the 21700 battery is slightly larger, it has higher energy/power and runtime. The mAh of these batteries is an important factor to consider. The mAh capacity of 18650 batteries will range from 2000 to 3500. On 21700 batteries, you can expect mAhs ranging from 3000 to 5000. You may come across advertisements for 18650 batteries that claim to have capacities of up to 9000 mAH.

The 18650 rechargeable battery offers strong dependability and stability, whereas the 21700 battery has a substantially higher performance index than the 18650 battery. Furthermore, when compared to other battery models, the raw materials, production technology, and technological processes of the 21700 rechargeable battery level are more advanced than the level of the 18650 rechargeable battery. As a result, the best fit is between the 18650 and 21700 production lines.

18650 Datasheet PDF