What is an 18650 battery? What is the difference between 18650 battery and soft pack lithium battery?

It is believed that many people in the battery market can hear the term 18650 battery, but few friends have seen the battery labeled 18650 battery in the market. At this time, some friends will have questions: What is the 18650 battery? Today, this article will solve this problem, and also answer the difference between 18650 battery and flexible lithium battery?


What is an 18650 battery?


18650 is the ancestor of lithium ion battery. A standard lithium-ion battery model set by Japanese SONY Company in order to save costs that year, in which 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 than in civil use. The common batteries are also used more in notebook batteries and high-end flashlights.


18650 Battery Advantages


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



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



3. High safety performance. 18650 lithium battery has high safety performance and is non explosive and non combustible; Non toxic, pollution-free, RoHS trademark certification; All kinds of safety performance are achieved at one go, and the number of cycles is more than 500; High temperature resistance, discharge efficiency reaches 100% at 65 ℃. To prevent battery short circuit, the positive and negative poles of the 18650 lithium battery are separated. Therefore, the possibility of short circuit has been reduced to the extreme. The protective plate can be added to avoid overcharge and over discharge of the battery, which can also extend 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. No memory effect. It is not necessary to empty the remaining power before charging, so it is convenient to use.



6. The internal resistance is small. The internal resistance of the composite cell is smaller than that of the ordinary liquid cell. The internal resistance of the domestic polymer cell can even be less than 35m Ω, greatly reducing the self consumption of the battery, extending the standby time of the mobile phone, and fully reaching the level of international standards. This polymer lithium battery which supports large discharge current is an ideal choice for remote control model and is the most promising product to replace nickel metal hydride battery.



7. The 18650 lithium battery pack can be combined in series or parallel.



8. It is widely used. Notebook computers, walkie talkies, portable DVDs, instruments, audio equipment, aircraft models, toys, video cameras, digital cameras and other electronic equipment.




18650 Disadvantages



Fixed volume. This is the biggest disadvantage of the 18650 battery. It is not well positioned in some notebooks or products. Of course, this disadvantage can also be said to be an advantage. This is a disadvantage compared with the customizable and changeable size of other polymer lithium batteries and other lithium batteries. Compared with some products with specified battery specifications, it has become an advantage.




Explosive. 18650 lithium batteries are prone to short circuit or explosion, which is also relative to polymer lithium batteries. Compared with ordinary batteries, this disadvantage is not so obvious.




Poor safety. 18650 lithium battery production requires protective lines to prevent the battery from being overcharged and causing discharge. Of course, this is necessary for lithium batteries, which is also a common disadvantage of lithium batteries, because the materials used for lithium batteries are basically lithium cobalate materials, while lithium cobalate batteries cannot discharge at high current, and their safety is poor.




High production conditions. 18650 lithium battery requires high production conditions. Compared with ordinary battery production, 18650 lithium battery requires high production conditions, which undoubtedly increases production costs.




What is the difference between 18650 battery and soft pack lithium battery?




The most intuitive difference between the 18650 lithium battery and the soft packed lithium battery is that the 18650 lithium battery is a cylindrical steel shell battery with basically the same size, while the soft packed lithium battery can be of any shape and size, and the shell is an aluminum plastic film packed battery.



The difference between 18650 lithium battery and soft packed lithium battery is that the materials used are different, such as electrolyte, conductive agent, electrode formula proportion, etc., and the production process is also different. The 18650 lithium battery is generally packaged with a steel shell (18 indicates a diameter of 18mm, 65 indicates a length of 65mm, and 0 indicates a cylindrical battery). The structure of the internal electrode sheet and diaphragm is wound. The outer package of lithium polymer flexible battery is made of aluminum plastic film, and the inner electrode sheet and diaphragm are stacked (layer by layer).



Another difference between the 18650 lithium battery and the soft packed lithium battery lies in the shape of the electrolyte in the battery's internal material: the electrolyte in the lithium polymer soft packed battery is polymer, generally gel or solid, while the electrolyte in the 18650 lithium battery is generally liquid.




The third difference is in the discharge performance of lithium battery with high current rate. The flexible lithium battery can achieve a higher magnification than the 18650 lithium battery. In terms of high current discharge stability, the flexible lithium battery has better performance. In terms of the same discharge requirements and capacity, the flexible lithium battery can customize the corresponding shape of the battery according to the space form of the product battery compartment to achieve a more portable form.