News - Structure of cylindrical lithium battery

The circular lithium battery refers to the cylindrical lithium battery. The earliest cylindrical lithium battery was the 18650 lithium battery invented by SONY in 1992. Because the 18650 cylindrical lithium battery has a long history, the market penetration rate is very high. Cylindrical lithium batteries use a fairly mature winding process, with a high degree of automation, stable product quality, and relatively low cost. There are many types of cylindrical lithium batteries, such as 14650, 17490, 18650, 21700, 26650 and so on. Cylindrical lithium batteries are more popular among lithium battery companies in Japan and South Korea. There are also large-scale enterprises in China that produce cylindrical lithium batteries.

   With the further expansion of the electric vehicle market and the continuous improvement of the requirements for the cruising range, vehicle companies have put forward higher requirements for power batteries in terms of energy density, manufacturing costs, cycle life, and product additional attributes. Under the premise that no major breakthrough has been made in the field of raw materials, appropriately increasing the volume of the cylindrical battery to obtain more battery capacity has become an exploreable direction. At present, Tesla has started the large-scale production of 21700 batteries and plans to use them on Tesla Model 3. If it passes the test on other Tesla models, it will replace all the 18650 batteries previously used. Tesla The approach may lead a “21700 trend” worldwide.

  Cylindrical lithium battery type classification

   1. Cylindrical primary batteries, mainly No. 5 and No. 7 batteries, other models are not introduced one by one, please consult the manufacturer for details;

   AA battery, the general size is: diameter 14mm, height 49mm;

   AAA battery, the general size is: diameter 11mm, height 44mm.

   2. Cylindrical lithium batteries, the main models are 18650, 16650, 14500, etc.

  18650 means 18 mm in diameter and 65 mm in length. The AA battery model is 14500, 14 mm in diameter and 50 mm in length. Generally, 18650 batteries are used more in industry and few in civilian use. The common ones are also used in notebook batteries and high-end flashlights.

  18650 is only the size of the battery. According to the battery type, it can be divided into 18650 for lithium ion, 18650 for lithium iron phosphate, 18650 for nickel metal hydride (rarely), and the common 18650 is for lithium ion.

  1. The capacity of 18650 lithium battery with large capacity is generally between 1200mah~3400mah.

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

3. High safety performance 18650 lithium battery has high safety performance. 18650 was born in 1996. After decades of development, 18650 lithium battery has realized fully automated production. The battery voltage, internal resistance, capacity, and self-discharge are very consistent. Well, it is currently the preferred model in various industries; it has good high temperature resistance, and the discharge efficiency is 100% under 65 degrees. In order to prevent the battery from short-circuiting, the positive and negative electrodes of the 18650 lithium battery are separated. Therefore, the short-circuit phenomenon may have been reduced to the extreme. A protection board can be installed to avoid overcharge and overdischarge of the battery, which can also extend the service life of the battery.

  4, high voltage 18650 lithium battery voltage is generally 3.6V, 3.8V and 4.2V, 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, can be combined in series or parallel to form a 18650 lithium battery pack

  7. Wide range of use: notebook computers, walkie-talkies, portable DVDs, instrumentation, audio equipment, model airplanes, toys, camcorders, digital cameras, new energy vehicles, medical industry and other electronic equipment.

   8. In the case of the same brand, the price of the battery is more advantageous. The various parts of the battery have been manufactured in mature and large quantities. The production cost is greatly reduced, so the cost performance is the best choice.


Post time: Jan-18-2021