Lithium-ion batteries have the advantages of light weight, large capacity, and no memory effect, so they are widely used. Many digital devices use lithium-ion batteries as power sources, although their prices are relatively expensive. Lithium-ion batteries have high energy density, their capacity is 1.5 to 2 times that of nickel-metal hydride batteries of the same weight, and they have a very low self-discharge rate. In addition, lithium-ion batteries have almost no "memory effect" and the advantages of no toxic substances are also important reasons for their wide application. There are also many types of lithium batteries. This article compares the two types of lithium batteries: 18650 lithium battery and 26650 lithium battery.

Which is better, 18650 lithium battery or 26650 lithium battery?

1. 18650 lithium battery

18650 lithium battery where 18 represents a diameter of 18mm, 65 represents a length of 65mm, and 0 represents a cylindrical battery. Generally, 18650 batteries are used more in industry, but few in civilian use. The most common ones are laptop batteries and high-end flashlights.

(1) Advantages of 18650 lithium battery

1. The capacity of 18650 lithium battery is generally between 1200mah and 3600mah, and the general battery capacity is only about 800mah. If combined into a 18650 lithium battery pack, the 18650 lithium battery pack can easily exceed 5000mah.

2. Long service life The 18650 lithium battery has a long service life, and the cycle life can reach more than 500 times during normal use, which is more than twice that of ordinary batteries.

3. High safety performance 18650 lithium battery has high safety performance, no explosion, no burning; non-toxic, non-polluting, certified by RoHS trademark; various safety performances are completed in one go, the number of cycles is more than 500 times; high temperature resistance performance is good, under the condition of 65 degrees The discharge efficiency reaches 100%. In order to prevent the short circuit of the battery, the positive and negative electrodes of the 18650 lithium battery are separated. Therefore, the possibility of short-circuiting has been reduced to the extreme. A protection board can be added to avoid overcharging and overdischarging of the battery, which can also prolong the service life of the battery.

4. High voltage The voltage of 18650 lithium battery is generally 3.6V, 3.8V and 4.2V, which is much higher than the 1.2V voltage of nickel-cadmium and nickel-hydrogen batteries.

5. There is no memory effect. It is not necessary to empty the remaining power before charging, which is convenient to use.

6. Small internal resistance: The internal resistance of the polymer battery is smaller than that of the general liquid battery. The internal resistance of the domestic polymer battery can even be below 35mΩ, which greatly reduces the self-consumption of the battery and prolongs the standby time of the mobile phone. In time, it can fully reach the level in line with international standards. This polymer lithium battery that supports large discharge current is an ideal choice for remote control models, and has become the most promising product to replace nickel-metal hydride batteries.

7. It can be combined in series or in parallel to form a 18650 lithium battery pack

8. Wide range of use laptops, walkie-talkies, portable DVDs, instrumentation, audio equipment, model aircraft, toys, video cameras, digital cameras and other electronic equipment

(2) Disadvantages of 18650 lithium battery

The biggest disadvantage of the 18650 lithium battery is that its size has been fixed, and it is not very well positioned when installed in some notebooks or some products. Of course, this disadvantage can also be said to be an advantage, which is compared to other lithium batteries such as polymer lithium batteries. This is a disadvantage in terms of customizable and resizable. Compared with some products with specified battery specifications, it has become an advantage.

The 18650 lithium battery is prone to short circuit or explosion, which is also relative to the polymer lithium battery. If it is relatively ordinary batteries, this disadvantage is not so obvious.

18650 lithium battery production requires protection circuits to prevent the battery from being overcharged and causing discharge. Of course, this is necessary for lithium batteries, which is also a common drawback of lithium batteries, because the materials used in lithium batteries are basically lithium cobalt oxide materials, and lithium batteries made of lithium cobalt oxide materials cannot be discharged at large currents, and their safety poor.

18650 lithium battery requires high production conditions. Compared with general battery production, 18650 lithium battery has high requirements for production conditions, which undoubtedly increases the production cost.

2. 26650 lithium battery

26650 lithium battery is a model specification of cylindrical lithium battery. Used in power tools, lighting, wind and solar energy storage, electric vehicles, toys, instrumentation, ups backup power supply, communication equipment, medical equipment and military lights. The definition rule of its model is: 26650 type, which means that the diameter of the battery is 26mm, the length is 65mm, and the battery is cylindrical.

3. Which one is better, 18650 lithium battery or 26650 lithium battery?

1. Battery volume comparison: The volume of 26650 lithium batteries is larger than that of 18650 lithium batteries. Their cell heights are the same, and the cell diameters are different. The 26650 lithium battery cell diameter is 26mm, while the 18650 lithium battery cell diameter is 18mm.

2. Battery capacity comparison: The battery capacity of 26650 is larger than that of 18650 under the same battery material. Assuming that the 26650 battery with the same ternary material is generally around 5200mAh, the capacity of 18650 battery is mostly around 2600mAh.

3. Application environment comparison: 18650 lithium batteries are used in lighting lamps batteries, industrial supporting lithium battery packs, power tool batteries, electric bicycle batteries, power lithium battery packs, etc., while 26650 lithium batteries are used in integrated solar street light lithium batteries There are many aspects such as groups, energy storage stations, and solar energy storage batteries.