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18650 Battery vs 21700: How Do Both Batteries Differ?

SONY first introduced the lithium batteries. Li-ion is well-known in the marketplace as a result of its recyclability and high-energy density. In addition, it has been promoted greatly during the information age process of human electronics

As a result of this, lithium ion was elected as a successful technology that came to be during the twentieth century. This lithium-ion’s performance with respect to fast-charging and safety can be seen in lots of electrical appliances.

There is a tough debate when it comes to comparing the 18650 Battery vs 21700. One of the popular debate questions goes thus. Why did Tesla replace the initially used 18650 battery in its electric vehicles with 21700? Also, what benefits does the 18650 battery offer? And what areas can the 21700 be applicable?

This is the article, which will help you understand and answer these questions better.

What is the 21700 Battery?

18650 Battery and 21700
18650 Battery and 21700

The 21700 battery can be described as a short-hand for a lithium ion rechargeable battery which has its diameter as 21 mm as well as a length of about 70 mm. This battery first became well-known during their utilization in different electric cars like electric scooters and Tesla. Presently, it is usually utilized in flashlights and vaping.

Benefits of 21700 Battery Cells

In the Tesla Model 3, the batteries used were changed from the initial 18650 to the 21700 cells. This has caused so many people to wonder what makes 21700 batteries so special. Below are some important benefits you should know.

Greater cell capacity

There is a limitation in the 18650 cells’ battery capacity which is limited to about 3600mAh due to its size. Moreover, the 21700 battery can reach its highest capacity at 5000mAh, which is a 42 percent increase.

Also, for the e-cigarette or flashlight users, this means that about 142% of the initial running time for the single charges. This is invaluable especially for the heavy users. Since, they are not up to 1” in diameter, the flashlights that use these batteries could still fit into the standard 1” weapon holsters and mounts!

Low cost for every Wh

Regarding the official information of Tesla, the cost of the 21700 battery system is around $155 per kWh. The 18650 battery on the other hand costs $171 per kWh. There if the 21700 cells were installed on the Tesla Model 3, then the battery system cost will be reduced by around 9%.

In fact, our calculation reveals that the 18650 battery needs extra raw materials so as to attain a similar capacity battery pack. This is why it comes with a higher cost.

Explaining further, a battery capacity of about 100Ah could be made up of 20 units of 200mah of the 21700 cells. However, when making use of the 18650 battery, it has to use up about 30 units of 3300mah of the 18650 cells.

Higher Energy Density

Working with the official disclosures of Tesla, the 18650 battery vs 21700 battery energy densities are about 250wh/kg and 300wh/kg respectively. Working with this comparison, the 21700 battery’s energy density is almost 20% more than the energy density of the 18650 battery.

What are the Applications of the 21700 Cells?


Tesla uses the Panasonic 21700 cell of 5000mAh for their car Tesla model 3


Fenix can be described as a company that manufactures lighting products. One of their flashlights (PD36R) specially makes use of the 21700 battery cells. This company clarified that after changing from the 18650 to the 21700 cells, there was a great improvement in the duration time for each battery


Electronic cigarettes aren’t sensitive with respect to cost. The fact is that some people wish to buy the vaping which can be utilized for a long time at 142%.

What is the 18650 Battery?


The 18650 battery can be described as a lithium ion rechargeable battery which has a diameter of 18 mm as well as a length of 65 mm. As a result of their superior discharge rate and capacity, they are usually utilized in scooters, laptops, flashlights, as well as devices that consumer high power.

Furthermore, Tesla Model S makes use of the 18650 cells. This cell first became well-known in some electric cars such as electric scooters and Tesla.

Benefits of the 18650 Battery

Since the original design of the 18650 battery, it is still very useful and relevant today. Many scooters, tricycles, as well as other consumer products still make use of the 18650 cells. Below are the main benefits of the 18650 battery.

 Effective Heat Dissipation Performance

When comparing the 18650 battery vs 21700 battery, you will discover that the thickness and winding length of the 21700 battery is larger than the 18650 battery. Also, regarding heat dissipation, when both batteries work, the 18650 battery comes with a better performance.

Adequate supply and high-cost performance

Over three decades ago, Sony launched the 18650 battery. In 2017, Panasonic and Tesla jointly launched the 21700 battery. The expansion of the market for the 18650 battery vs 21700 battery has been on for two decades and five years respectively. So it’s clear that the 18650 cells have a greater market expansion. Furthermore, in markets, there are over 50 manufacturers involved in the production of the 186500 cells, in contrast to the less than 10 manufacturers involved in the production of the 21700 cells.

Also, this leads to the idea that 18650 batteries present on the marketplace have always been at affordable prices and insufficient supply.

How to Produce the 18650 Cells?

The manufacturing processes of the 18650 battery vs 21700 battery are virtually the same. Just the “winding” pattern comes with a little difference. Furthermore, the 21700 battery is fatter and usually requires extra turns in contrast to the 18650 battery that is slimmer and requires less turns.

What are the Types of 18650 Batteries?

You can fund different types of 18650 batteries in the market. They come with different capacities, ranging between 2Ah and 3.5Ah. Furthermore, the different types have different cycles because they have different production processes and different cycle lives. The NCM 18650 cells come with a lifespan of about 300 to 1000 times.

What are the Applications of the 18650 Battery?

The 18650 battery is applicable in the following.

18650 Battery vs 21700 Battery: Are they the Same?

So many people have been confused about the difference between the 18650 battery vs 21700 battery. They are not the same, but different. First, the 18650 battery is a lithium cylindrical battery which has a diameter of 18 mm as well as a height of 65 mm. However, the shape of the 21700 cell is cylindrical, while its diameter and height are slightly larger at 21 mm and 70 mm respectively.

Another difference between 18650 battery vs 21700 battery is their capacity. The capacity of the former falls within 2600mAh and 3600mAh, while that of 21700 battery is between 4000mAh and 6000mAh. What this means is that the 21700 battery lasts longer compared to the 18650 battery before recharging.

Although both batteries can be utilized in small and portable devices, certainly they aren’t alike. However, both of them share one purpose. This is to power all our gadgets. At times, you may discover that these batteries have close voltage measurements, there are extra digits close to the end, which reveals the number of amp hours every cell offers before exhaustion.

Majority people believe that the 18650 battery vs 21700 battery are identical for most parts when we talk of their performance. The major difference is that the 21700 battery seems to be much more prominent when it comes to size. Therefore, if you seek for a battery which offers the best possible performance, then any of the two between 18650 battery vs 21700 battery will be perfect.

It is very important to known that 21700 batteries would be a bit too big to fit into the 18650 battery holder.

18650 Battery vs 21700 Battery: Which is Better?

The capacity of a battery is measured in milliamp hours (mAh) or amp hours (Ah). The 21700 battery comes with a capacity of around 4000 mAh and 6000mAh, while the 18650 battery capacity falls between 2600mAh and 3600mAh. This means that the capacity of the 21700 battery is about two times that of 18650 batteries.

Furthermore, the main disadvantage of making use of the 21700 battery is because they aren’t as standard compared to the 18650 batteries. This is why finding them may be more difficult and they could be more expensive. Moreover, with the great increase in the popularity of the 21700 batteries, this will most probably change very soon.

With respect to the market analysis conducted recently, the most popular of all the 21700 batteries is the Samsung lithium-ion INR21700-40T. This battery capacity is high at 4000mAh and it has maximum outputs of 40A. This makes it great for any high-drain device. Also, it features the latest charging technology of Samsung. This allows fast charging of about 15 minutes when utilized with any compatible chargers.

In addition, they are lots of 18650 batteries present in the marketplace. However, users believe that the best is Panasonic lithium-ion NCR18650B battery. High quality batteries provide great performance as well as long life. Furthermore, it is priced reasonably compared to other well-known brands.

Does the 21700 Battery Fit the 18650 Battery?

It is very important to take note that 21700 batteries would be a bit too big to fit into the 18650 battery holder. Moreover, speaking generally, the 21700 batteries would fit into the 18650 battery holder. This may not be great for performance reasons.

Also, there are concerns regarding if the 21700 battery will or will not overheat when placed in the 18650 holders. There is nothing to worry about as both batteries have different sizes and shapes. Therefore, they won’t make any contact, neither will any short circuits.

18650 battery vs 21700 battery: What are the Similarities Between them?

The similarities found between 18650 battery vs 21700 batteries are striking. These types of batteries are useful in different devices that require a source of power like smoke alarms or flashlights, etc. Also, they have high capacity in contrast to other options. Examples here are alkaline battery, and the Nickel metal hydride battery.

Both of them have a cylindrical shape and with respect to length, they have slight differences. This additional length ensures additional capacity. The battery capacities between 18650 battery vs 21700 battery are 3600mAh and 6000mAh respectively. Also, both batteries are majorly lithium-ion batteries.

Another similarity between 18650 battery vs 21700 battery is that they are rechargeable and could be utilized in devices, which need a power between 3.2 and 3.7v depending on if it is lithium iron or lithium ternary phosphate power.

Related Questions

Can the 21700 battery be used in vapes?

The 21700 battery can be used in vapes. However, ensure the battery works well with whatever vape mod you are using. Also, not all the mods will work perfectly well with all the batteries.

Can I make use of the 21700 battery instead of the 18650 battery?

Yes you can. However, take note that not all the 21700 batteries out there are created equally. Some are specially designed for different low-drain applications and some for high-drain applications.

Final Thoughts: 18650 battery vs 21700 battery

Today, 21700 batteries are now more popular. The 21700 battery provides extra power compared to the 18650. This makes it great for any high drain device like power tools and electric cars. Though several manufacturers still release some compatible products, many individuals still believe that the 21700 batteries would eventually take the place of the 18650 battery as the only industry standard.

Also, if you are seeing a long-lasting and powerful battery to help with you project, make sure that you consider making use of the 21700 battery. Asides explaining the differences between 18650 battery vs 21700 battery, we also compared the differences, as well as the differences between the lithium, batteries and other battery types such as ni-mh vs li-ion battery, with the belief that find something valuable and get some useful and reliable information.




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