Lithium-ion batteries come in a variety of sizes, but some common cylindrical sizes include 18650, 26650, and 21700.
These sizes refer to the physical dimensions of the battery cell itself. The naming convention is based on diameter and length, typically expressed in millimeters. Let's break down these common sizes:
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18650: This is one of the most popular sizes. It has a diameter of 18mm and a length of 65mm. They are often used in laptops, power tools, and electric vehicles.
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26650: This cell is larger, with a diameter of 26mm and a length of 65mm. Due to their larger size, these cells offer higher capacity compared to 18650s.
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21700: A more recent standard, the 21700 has a diameter of 21mm and a length of 70mm. It offers a good balance between capacity and size, making it increasingly popular in electric vehicles and other high-power applications.
Here's a table summarizing the dimensions:
| Battery Size | Diameter (mm) | Length (mm) |
|---|---|---|
| 18650 | 18 | 65 |
| 26650 | 26 | 65 |
| 21700 | 21 | 70 |
It's important to note that this only covers some of the common cylindrical sizes. Lithium-ion batteries also come in prismatic and pouch formats, which have different dimensions and naming conventions. Furthermore, the specific capacity (mAh or Ah) of a lithium-ion battery will vary depending on the manufacturer and the specific chemistry used, even within the same physical size.
