The 18650 cell is one of the most popular types of rechargeable lithium-ion batteries, and for good reason. They are readily available and reasonably priced. The 21700 lithium batteries are a more recent invention that has some clear advantages over the 18650, but it also comes with an increased price tag.
However, they both do have their advantages and drawbacks, 21700 vs 18650 battery. Which type of battery should you buy? Keep reading to learn about the differences between these two types!
Common similarities between 21700 and 18650 battery
There are several key similarities between a 21700 and 18650 battery that makes them both great options for LEV (light electric vehicle) and other applications.
Firstly, both lithium-ion batteries have a high discharge rate, meaning that they can provide the high levels of power required by LEVs.
Secondly, both the 18650 battery pack and the 21700 battery pack come with the same voltage, which is 3.7 volts. This is the standard voltage for LEV batteries, and it ensures that there are no compatibility issues between different types.
Thirdly, they can be used in a wide range of temperatures, making them suitable for use in a variety of climates.
Fourthly, 18650 and 21700 cells are cylindrical.
Finally, both types have a long lifespan, meaning that they will not need to be replaced as often as other types of batteries.
If you are more interested in 18650 cells then you should know how to choose the best 18650 battery for LEV.
And if you are more interested in 21700 cells then you should know how to choose the best 21700 battery for LEV.
Major differences between 21700 vs 18650 battery
There are many differences between 21700 and 18650 batteries. Some of these differences include:
Power output
When choosing which type of lithium-ion battery to buy for your device, you should consider how much power output you need. If you know that the application will require a lot of energy and you don’t want something too bulky or heavy, then it would be best to go with 21700 cells over 18650.
Battery cell weight
21700 batteries weigh around 60g, compared to around 48g for 18650. But their weight can vary depending on specifications.
Price
You should consider the price difference between the two types- 21700s tend to be more expensive than 18650 batteries. This is because the 21700 battery is newer and has more features than the 18650.
Energy Density
21700 batteries have a higher energy density than 18650.
The 18650 is one of the most popular types of rechargeable lithium-ion batteries, 18650 has a capacity of 2600-3500mAH while the 21700 has a higher capacity can reach up to 5000mAH, which means 21700 cylindrical li-ion cells have more energy density, which can result in more runtime.
Damage
Additionally, 18650 batteries are more susceptible to damage from external factors such as heat and pressure.
Dimension
18650 batteries measure 65mm in length and 18 mm in diameter while 21700 batteries are 70mm long and 21mm wide. The dimensions of the two types vary greatly, with one being significantly longer than the other. This is because of their different capacities—the larger capacity of the 21700 lithium-ion allows it to be larger in size and have high power.
Are 21700 batteries better than 18650？
21700 batteries are newer and larger than 18650. They offer more capacity and discharge at higher currents. 21700 batteries also have a longer cycle life. However, they are more expensive and may not fit in all devices that use 18650 batteries.
So, what’s the verdict? If you need the extra capacity and discharge current, go with a 21700 battery. If you’re looking to save some money or your device only takes 18650 batteries, stick with the 18650.
Can you charge 21700 batteries in a 18650 charger?
The quick answer is yes, you can charge 21700 batteries in a 18650 charger. However, we recommend using a dedicated 21700 charger whenever possible for the best results.
Does 21700 last longer than 18650?
The simple answer is yes, 21700 batteries typically last longer than 18650 batteries. One of the main reasons that the 18650 lithium-ion battery is less powerful than the 21700 is that they have a lower capacity and energy densities are lower.
This means that they can’t store as much energy as 21700 lithium-ion, which can result in less runtime.
It is important to note that the longevity of a battery depends on a variety of factors, including the frequency of usage, storage, and type of device that use it. So, while 21700 batteries may typically last longer than 18650 batteries, there are no guarantees.
Do 21700 vs 18650 battery have different applications?
21700 vs 18650 battery for application to maximize efficiency, cost-effectiveness, or power output.
You would want something that can last longer, weigh less based on the same energy content, have more weight efficiency, and give you more power to get the job done right.
In this case, you need something that works well with high power output, which is why the 21700 cells are probably your best bet.
How does the size of lithium-ion batteries affect their performance in an application that requires them to be lightweight and compact?
The size of a lithium-ion battery can be important in applications that require them to be lightweight and compact. For example, if you are using a battery in a drone, the less weight the better.
In this case, a 18650 battery would be a better choice because it is lighter in weight and has more weight efficiency.
Application of 21700 lithium-ion batteries
| Application | |
| LEVs | LEVs commonly use 21700 batteries. This is because they have a high cell voltage, high discharge rate, and low self-discharge rate.    |
| Solar Energy | Solar energy storage systems require batteries that can be charged quickly to store the energy generated by solar panels. |
| Power Tools | 21700 batteries are also used in power tools and other devices that require a high level of power. This is because they can provide the high levels of power required by these devices. |
| Laptops | 21700 has a higher energy density than 18650. This means that their rechargeable lithium-ion cells can store more energy resulting in a much smaller battery pack. |
| Electric Vehicles | The high-density li-ion cells in 21700 make them ideal for use in high-voltage applications such as electric vehicles. |
| Medical Devices | This is because 21700 batteries have a low self-discharge rate. Medical devices require batteries that can maintain their charge for a long period of time to ensure that the medical device is always ready for use. |
| Vapes | The high discharge rate of 21700 batteries means that they can provide the high levels of power required by vapes. |
Application of 18650 batteries on electronic devices
| Application | |
| LEVs | They are also used in LEVs such as electric bikes, electric motorcycles, electric scooters, etc. where cost, space, and weight are factors of consideration.  |
| Portable devices | 18650 can be found in portable devices like satellite phones, remote-control toys, and controllers. |
| Flashlights | 18650 batteries are commonly used in flashlights and other electronic devices that require a lower level of power. |
| Laptops | Many laptops use 18650 because they are powerful and have a long lifespan. Laptops require batteries that can provide a long runtime. |
| Vapes | 18650 batteries are powerful and can provide the high levels of power required by vapes and vaping accessories. |
| Electric Cars | The large battery capacity of 18650is ideal for electric cars since they require a lot of power. |
| Drones | Drones require batteries that can provide a high level of power for a long period of time. The lightweight li-ion cells are ideal for drones. |
How to choose the correct lithium battery for your electric mobility?
Tritek, as a professional lithium-ion batteries manufacturer, can provide different battery packs to install in various drive systems, such as electric bikes, electric scooters, electric motorcycle / mopeds, golf Caddy, wheelchairs, cargo bike, etc. We usually sort battery packs based on their voltages.
Initially, we would like to introduce our “Starter” — 36V lithium battery packs for electric bikes and electric scooters. It’s a battery pack shaped into a slim frame-mounted electric road bike or mountain bike. If you need a battery hidden in the electric bike and are looking for high output, lightweight, and in a small volume, an in-tube battery pack is perfect for you.
FAQ
1. What are the different types of lithium-ion cells used in 18650 and 21700 batteries?
Lithium-ion batteries, including both 18650 and 21700 cells, can be made using different chemistries, such as lithium manganese oxide (LMO), lithium iron phosphate (LFP), and lithium cobalt oxide (LCO).
2. How does the nominal capacity differ between 18650 and 21700 lithium cells?
The nominal capacity of lithium cells varies between 18650 and 21700 batteries. Typically, 18650 cells have a capacity range of 2600-3500mAh, whereas 21700 cells offer a higher capacity, often reaching up to 5000mAh.
3. Can other battery types offer more room for energy storage compared to lithium-ion cells?
While lithium-ion cells, such as 18650 and 21700, are renowned for their high energy density and efficiency, other battery types like solid-state batteries and lithium-sulfur batteries are being developed to offer even more room for energy storage. However, these alternatives are still in experimental stages and not as widely available or proven as lithium-ion cells for practical use in applications such as LEVs and consumer electronics.
How much do you know about Li-ion battery cells? Here is a comprehensive explanation from Tirtek’s R&D Director. ↓↓↓
