Structure of cylindrical lithium battery

The circular lithium battery refers to the cylindrical lithium battery. The earliest cylindrical lithium battery is the 18650 lithium battery invented by SONY in 1992. Because the 18650 cylindrical lithium batteries have a long history, the market penetration rate is very high. The cylindrical lithium battery adopts a fairly mature winding process, with 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, etc. Cylindrical lithium batteries are popular among lithium battery companies in Japan and Korea, and there are also quite large companies in China that produce cylindrical lithium batteries.

With the further expansion of the electric vehicle market and the continuous improvement of the cruising range, the vehicle manufacturers have put forward higher requirements on the energy density, manufacturing cost, cycle life and product additional attributes of the power battery. Under the premise that the raw material field has not yet made a huge breakthrough, appropriately increasing the volume of the cylindrical battery to obtain more battery capacity becomes a searchable direction. At present, Tesla has started the large-scale production of 21700 batteries, and plans to use it on the Tesla Model 3. If it is tested on other models of Tesla, it will replace the previously used 18650 battery, Tesla. The practice may lead a "21700 trend" around the world.

Cylindrical lithium battery various models

First, the cylindrical primary battery, mainly the 5th and 7th batteries, other models are not introduced one by one, you can consult the manufacturer;

No. 5 battery, the general size is: diameter 14mm, height 49mm;

The 7th battery has a general size of 11mm in diameter and 44mm in height.

Second, cylindrical lithium battery, the main models are 18650, 16650, 14500, etc.

The 18650 means 18 mm in diameter and 65 mm in length. The model number of the No. 5 battery is 14,500, 14 mm in diameter and 50 mm in length. Generally, the 18650 battery is used in the industry, and there are few civilians. The common ones are used in laptop batteries and high-end flashlights.

The 18650 is just the size of the battery. It can be divided according to the type of battery. 18650 for lithium ion, 18650 for lithium iron phosphate, 18650 for nickel hydrogen (rare), and the common 18650 is lithium ion.

1, the capacity of large 18650 lithium battery capacity is generally between 1200mah ~ 3400mah.

2, long life: 18650 lithium batteries have a long service life. The normal life cycle can reach more than 500 times, more than twice the average battery.

3, high security 18650 lithium battery safety performance, 18650 was born in 1996, after several decades of development, 18650 lithium battery has been fully automated production, battery voltage, internal resistance, capacity, self-discharge consistency is very Well, it is currently the preferred model for various industries; high temperature resistance is good, and the discharge efficiency is 100% under 65 degrees. In order to prevent battery short circuit, the positive and negative poles of the 18650 lithium battery are separated. So the possibility of its short circuit has been reduced to the extreme. A protective plate can be added to prevent the battery from overcharging and over-discharging, which also extends the battery life.

4. The voltage of the 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.

5, no memory effect: you don’t have to empty the remaining power before charging, it’s easy to use.

6, it can be combined in series or parallel to form a 18650 lithium battery pack.

7, the use of a wide range of notebook computers, walkie-talkies, portable DVD, instrumentation, audio equipment, aircraft models, toys, cameras, digital cameras, new energy vehicles, medical industry and other electronic equipment.

8, under the same brand situation, the price of the battery is more advantageous. The various accessories of the battery have been realized in mature mass production, and the production cost is greatly reduced. Therefore, the cost performance is the best choice.

The page contains the contents of the machine translation.