The Various Sizes of Lithium Ion Cells: Which One is Right for You?

As the demand for portable electronics continues to soar, it’s no surprise that lithium-ion batteries have become one of the most widely used power sources. These rechargeable cells are not only lighter and more efficient than traditional batteries but also come in various sizes to suit different applications. However, with so many options available, choosing the right size can be overwhelming. In this blog post, we’ll explore some of the most common lithium-ion cell sizes – from 650 to 26650 – and help you determine which one is best suited for your needs!

650 Cells

650 cells are one of the smallest lithium-ion batteries available on the market, measuring only 6.5mm in diameter and 50mm in length. Due to their small size, they are often used in devices that require low power output such as hearing aids or small remote controls.

The capacity of a 650 cell is relatively low compared to larger lithium-ion battery options, with an average capacity of around 100mAh. This means that these cells may need to be replaced more frequently than larger ones if used for high-power applications.

One advantage of using smaller cells like the 650 is their ability to be wired together in series or parallel configurations to increase voltage or capacity. This makes them ideal for custom battery pack designs where space is limited.

It’s important to note that not all electronics can accommodate these tiny batteries due to compatibility issues and safety concerns associated with over-discharging or overheating. Therefore, it’s essential always to follow manufacturer recommendations when selecting a battery for your device’s specific needs.

20700 Cells

Looking for a lithium-ion cell that is not too small or too big? The 20700 cells might be the perfect fit for you. These cylindrical batteries measure 20mm in diameter and 70mm in length, making them slightly larger than their popular counterpart, the 18650.

One of the advantages of using 20700 cells is its higher energy density. This means that it can store more energy compared to smaller cells without taking up too much space. In addition, these cells have a lower internal resistance which makes them ideal for high-drain applications like electric vehicles and power tools.

Another advantage of using larger battery cells like the 20700s is its longer lifespan due to less wear on each individual cell when used in series configurations. This can lead to overall cost savings since fewer replacements will be needed over time.

However, it’s important to keep in mind that while these batteries offer many benefits, they may not always be compatible with all devices designed for smaller lithium-ion batteries such as smartphones or some vape mods.

If you’re considering switching over to this size of battery cell, make sure your device supports it before making any purchases.

21700 Cells

21700 cells are the latest and greatest addition to the lithium-ion battery family. They have quickly become a popular choice for high-performance devices due to their increased energy density and capacity compared to previous cell sizes.

These cells measure 21mm in diameter and 70mm in length, making them slightly larger than the standard 18650 cells but still compact enough for use in portable devices. The extra size allows for more active material within the cell, resulting in longer run times and faster charging speeds.

One of the major advantages of using 21700 cells is their ability to handle higher current loads without overheating or experiencing voltage drops. This makes them ideal for applications such as electric vehicles, power tools, and even drones.

Moreover, many manufacturers are now producing these cells with advanced safety features such as built-in protection circuits that help prevent overcharging or short-circuiting. These added safety measures make it easier for consumers to safely incorporate these batteries into their daily lives.

If you’re looking for a reliable battery solution that offers excellent performance while maintaining optimal safety standards, then 21700 lithium-ion cells may be just what you need!

26650 Cells

26650 cells are some of the largest lithium-ion batteries available on the market. These big boys pack a serious punch, with capacities up to 5000mAh or more! The added size and capacity make them ideal for use in high-powered devices that require long-lasting energy.

One advantage of using 26650 cells is their increased safety compared to smaller batteries. Because they have a larger surface area, heat dissipation is improved, reducing the risk of overheating and thermal runaway. Additionally, their size allows for thicker electrodes which can handle higher current loads without getting too hot.

These batteries are commonly used in electric vehicles due to their high power output and durability over time. They’re also popular among DIY enthusiasts who build custom battery packs for various projects such as flashlights or e-bikes.

If you need a reliable source of power that can handle heavy-duty applications, then consider investing in 26650 cells for your next project!


There are various sizes of lithium-ion cells available in the market, and choosing the right one for your device can be a daunting task. It is essential to consider factors such as the size of your device, power requirements, and cost when selecting a battery.

The 650-cell is perfect for small devices like flashlights and toys that require low power consumption. The 20700 cell offers more capacity than the 650 cell and is suitable for mid-sized devices like laptops. The 21700 cell provides even higher energy density than the previous two types and is ideal for high-performance devices such as electric cars.

If you need an extremely powerful battery with longer life cycles, then opt for the 26650 cell. Regardless of what type you choose, it’s crucial to purchase from reputable manufacturers who adhere to safety standards.

By understanding your device’s power demands and selecting a lithium-ion battery accordingly will enhance its overall performance while ensuring safety at all times.