18650 means it has a diameter of 18 mm and a length of 65 mm. A size 5 battery, on the other hand, has a diameter of 14500 and a length of 50 mm. 18650 batteries are generally more commonly used in industrial applications and less so in consumer use, primarily found in laptop batteries and high-end flashlights. So, what are the advantages and disadvantages of 18650 lithium batteries?
Advantages of 18650 lithium batteries
1. Large capacity: The capacity of 18650 lithium batteries is generally between 1200mAh and 3600mAh, while the capacity of ordinary batteries is only around 800mAh. If they are combined into an 18650 lithium battery pack, the capacity of the 18650 lithium battery pack can easily exceed 5000mAh.
2. Long lifespan: 18650 lithium batteries have a long lifespan, with a cycle life of more than 500 cycles under normal use, which is more than twice that of ordinary batteries.
3. High Safety Performance: 18650 lithium batteries offer high safety performance. To prevent short circuits, the positive and negative terminals of the 18650 lithium battery are separate. Therefore, the possibility of a short circuit is minimized. A protection board can be added to prevent overcharging and over-discharging, thus extending the battery's lifespan.
4. High voltage: The voltage of 18650 lithium batteries is generally 3.6V, 3.8V and 4.2V, which is much higher than the 1.2V voltage of nickel-cadmium and nickel-metal hydride batteries.
5. No memory effect: There is no need to completely discharge the remaining power before charging, making it convenient to use.
6. Low internal resistance: Polymer cells have lower internal resistance than ordinary liquid cells. Domestically produced polymer cells can even achieve an internal resistance below 35mΩ, significantly reducing battery self-discharge and extending phone standby time, fully meeting international standards. This type of polymer lithium battery, which supports high discharge current, is also an ideal choice for remote control models, becoming the most promising replacement for nickel-metal hydride batteries.
7. Can be connected in series or parallel to form an 18650 lithium battery pack.
8. Wide range of applications: laptops, walkie-talkies, portable DVDs, instruments, audio equipment, model airplanes, toys, video cameras, digital cameras and other electronic devices.
Disadvantages of 18650 lithium batteries
The biggest drawback of 18650 lithium batteries is their fixed size, which makes them difficult to position in some laptops or other products. However, this drawback can also be seen as an advantage, as it's a disadvantage compared to other lithium batteries like polymer lithium batteries, which offer customization and size variations. Conversely, it becomes an advantage for products with specific battery specifications.
All 18650 lithium battery manufacturers require protection circuits to prevent overcharging and subsequent discharge. This is essential for lithium batteries, and it's a common drawback because they primarily use lithium cobalt oxide, which cannot withstand high current discharges, resulting in lower safety.
The production conditions for 18650 lithium batteries are demanding. Compared to general battery production, 18650 lithium batteries have much higher requirements for production conditions, which undoubtedly increases production costs.
