What Are The Differences Between 18650, 26650 and 21700 Car Batteries? | IMREN

18650 is a lithium-ion battery, in which 18 implies a diameter of 18 mm, 65 implies a length of 65 mm, and 0 implies a cylindrical battery.

Characteristic:
Large capacity: The capacity of 18650 lithium battery is at least 1200 mah, or even 3600 mah, while that of ordinary cells is only about 500 mah.

High energy storage efficiency: good stability: full performance output can still be connected below 70 °. Generally, there are protective batteries inside to avoid battery burning.

No memory effect: it is not necessary to discharge all the remaining batteries before charging, and it can be charged and discharged at any time, which is convenient to use.

High cycle life of charge and discharge: the lithium battery has been cycled for tens of thousands of times, with good high temperature resistance.

Environmental protection, non-toxic: non-toxic, harmless, pollution-free, RoSH quality certification.

18650 battery 2200mAh 3.7V
Shelter function:
Overcharge protection: when the lithium battery is overcharged, the internal temperature rise of the battery will increase continuously, which increases the battery voltage detection system. When the overcharge voltage of the battery reaches a certain value or time period, the overcharge function will automatically start and stop to protect the battery.

Overdischarge protection: the battery is always in the overload output state. Generally, there is discharge protection. At this time, the battery will be in standby mode.

Over-current protection: the over-current protection value can be adjusted, some of which are several amperes, and can be set according to the actual situation.

Short-circuit protection: when the battery is disconnected, the over-current protection battery will not be burned.

In addition to these four sheltering functions, some also have the functions of temperature and balance. Generally, the PCM shelter system with multiple shelter functions is built into the battery.

18650 battery advantages:
Large capacity: The capacity of the 18650 battery is generally between 1200mah and 3600mah, and the general battery capacity is only about 800mah. If combined into 18650 battery pack, it can easily break through 5000mAh.

Long service life: 18650 battery has a long service life, and its cycle life can reach more than 500 times in normal use, more than twice that of ordinary battery.

High safety performance: 18650 battery has high safety performance. In order to avoid short circuit of the battery, the positive and negative poles of the 18650 battery are separated. Therefore, the possibility of short circuit has been reduced to the extreme. Shelter plate can be installed to avoid overcharge and overcharge of the battery and prolong the service life of the battery.

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 NiCd and NiMH batteries.
No memory effect: no need to empty the remaining power before charging, easy to use.

Small internal resistance: the internal resistance of polymer battery is smaller than that of ordinary liquid battery, and the internal resistance of domestic polymer battery can even be less than 35m Ω, which greatly reduces the battery consumption and extends the standby time of mobile phone. This polymer lithium battery supporting large discharge current is the ideal choice for remote control models, and has become the most promising product to replace NiMH batteries.
18650 lithium battery pack can be combined in series or parallel
Wide range of applications: 18650 batteries can be used for notebook computers, walkie-talkies, portable DVDs, instruments, audio equipment, aircraft models, toys, cameras, digital cameras and other electronic equipment.

Disadvantages:
Fixation of Chiwei leisure: The biggest disadvantage of the 18650 battery is that Chiwei leisure has been fixed, and the positioning is not very good when installed on some notebooks or products.

Of course, this can also be said to be an advantage. Compared with other polymer lithium batteries, this is a disadvantage in terms of customizable and variable-length micro leisure of lithium batteries. Compared with some products with specified battery specifications, it has become the upper hand.

Shelter circuit is required: 18650 battery production needs shelter circuit to avoid battery overcharge and discharge.

Although this is necessary for lithium batteries, it is also a common problem 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 can not be discharged at high voltage, their safety is very poor.

High production conditions: The 18650 battery has high production conditions. Compared with the general battery production, it requires high production conditions, which undoubtedly increases the production cost.


The 26650 battery is a cylindrical lithium battery with a diameter of 26mm and a length of 65mm. It is used for electric tools, lighting, wind and solar energy storage, electric vehicles, toys, instruments and meters, UPS backup power supply, medical equipment and military lamps, instruments and meters, UPS backup power supply, communication equipment, medical equipment and military lamps.

Comparison between 18650 battery and 26650 battery

Difference of rated capacity: the rated capacity of IFR26650 is 3000mAh, and the rated capacity of IFR18650 is 1100~1400mAh.

The diameter of IFR26650 is 26mm and that of IFR18650 is 18mm.

Different reference quality: the production test quality of FR26650 is 94g, and the IFR18650 is 45g.

The scope of application is different: 18650 lithium batteries are used for lighting, industrial supporting lithium batteries, electric tool batteries, electric bicycle batteries, power lithium batteries, etc., while 26650 batteries are used for integrated solar street lamp lithium batteries, energy storage stations, solar batteries, etc.

26650 battery will gradually replace 18650 battery in the application of power battery. With the wide use of lithium batteries, it is bound to become a trend that the large-capacity 26650 battery replaces the 18650 lithium battery which is the new trend of the 3C era.

The 21700 battery is a cylindrical battery with a diameter of 21mm and a height of 27mm. Its charging density is the highest and the lowest cost battery in the world today, with high cost performance.

21700 battery parameters:                               
High energy density: the energy density of the 21700 battery is higher than that of the famous 18650 battery. The number of single batteries used can be greatly reduced, and the cost will decrease after grouping.

Large battery capacity: the 18650 battery capacity is about 2600-3600mAh, while the 21700 battery supports more than 4000mAh, and even 5000mAh has been listed. And larger capacity is more and more conducive to extending the battery life of modern equipment.

High battery energy: the volume of rechargeable battery monomer increases by 35%. Take the Tesla 21700 rechargeable battery as an example, the energy of a single battery can be increased by 34.8 ah and 35%.

Light weight: the net weight of the system software is expected to be reduced by 10%, and the total capacity will exceed 21700. With the increase of monomer volume and monomer energy ratio, the total number of batteries required under the same kinetic energy can be reduced by about 1/3, and the total number of metal and electrical components selected for the battery pack can reduce the difficulty coefficient of the governance information system. After converting SDI (Samsung Digital Interface) into a new 21700 rechargeable battery, it was found that the net weight of the system software was reduced by 10% compared with the existing battery.

Comparison between 18650 battery and 21700 battery:
18650 rechargeable battery has high reliability and stability, and the performance index of 21700 battery is much higher than that of 18650 battery. In addition, compared with other battery models, the raw materials, processing technology and technical pace of the 21700 rechargeable battery are more advanced than the 18650 rechargeable battery. Therefore, the 18650 and 21700 production lines are the best match.