In recent years, the rapid development of the lithium battery industry has driven the transformation and development of various industries, except for the electric vehicle products that we often pay attention to. The electric tools used in daily life are increasingly inseparable from lithium batteries. At present, the vast majority of electric tools still use 18650 lithium batteries as the main power source, but with the emergence of 21700 lithium batteries, this situation is gradually being broken.
Should I choose 18650 or 21700 lithium battery for electric tools
21700, 18650, 20700, etc. only refer to the physical dimensions of lithium-ion batteries. For example, 18650 lithium batteries, 18 represents circumference, 65 represents length, and 0 represents cylindrical batteries. 18650 batteries are not only lithium batteries, nickel hydrogen batteries also come in 18650 size.
Compared to 18650 batteries, the additional 5mm length and 3mm diameter of 21700 cells can increase their volume by 47%. This also means an increase of 7700 cubic millimeters of space, which can be used to fill the anode, cathode, and electrolyte materials for energy transfer. It also means that 21700 lithium batteries can have higher capacity than 18650 lithium batteries.
Higher capacity is equivalent to having longer battery life.
The most obvious benefit compared to 21700 and 18650 is that the additional volume space allows it to have more energy to keep your tools running for longer periods of time. We see that batteries powered by 18650 cells have a capacity of 1.5Ah (1500mAh) to 3.0Ah (3000mAh) per battery. However, the high-end 18650 battery cells (3.0Ah) have encountered batch problems, which is why most manufacturers prioritize 2.5Ah (2500mAh) batteries.
On the other hand, for electric tool batteries, the starting capacity of 21700 cells is 3.0Ah (3000mAh), and the highest capacity can reach 4.0Ah (4000mAh). That's why we can see compact (1P) battery packs labeled as 3Ah or 4Ah, up to 12Ah (3P) large batteries.
The following is a comparison of the capacity of various specifications of conventional electric tool batteries.
eighteen thousand six hundred and fifty
Compact 1P battery: 2.0Ah – 3.0Ah (36 Wh – 54 Wh)
Universal 2P battery: 4.0Ah – 6.0Ah (72 Wh to 108 Wh)
Large capacity 3P battery: 9.0Ah (162Wh)
twenty-one thousand and seven hundred
Compact 1P battery: 3.0Ah – 4.0Ah (54 Wh – 72Wh)
Universal 2P battery: 6.0Ah – 8.0Ah (108 Wh – 144 Wh)
Large capacity 3P battery: 9Ah – 12Ah (162 Wh – 216 Wh)
*Note: The above does not apply to the nominal voltage of the battery.
How to choose between
18650 lithium battery and 21700 lithium battery
18650 lithium battery has been one of the lithium batteries used in power tools for a long time. In addition to its suitable size, its weight is also more suitable for carrying. The 21700 has a larger size and space than the 18650, as well as heavier weight and larger volume. However, it is clear that the 21700 can also provide stronger power and longer service life. If a trade-off must be made between two types of batteries, more attention should be paid to practical applications, as both batteries can meet the needs of power tools. How to choose is not difficult.
