There are a wide variety of mobile power products, and the variety of styles and product introductions make it difficult to make choices. The first thing to look at when choosing a mobile power supply is safety. The biggest factor in determining the safety of mobile power is the type of battery used inside. A poor quality battery is likely to explode during use, which will seriously affect it. The personal safety of users.
At present, the most commonly used mobile power batteries for mobile power in the market are lithium ion batteries (18650 batteries) and lithium polymer batteries. In terms of safety, lithium polymer batteries are better than lithium. Ion cells, and the difference in safety is not very large, so many consumers now prefer to spend a little more money to buy mobile batteries for mobile batteries, not only more reliable when charging, but also a longer life. some.
There are a lot of mobile power sources on the market that claim to use polymer batteries. The internal batteries are not the same type of 18650 batteries like the No. 5 battery, but this one looks slim and lighter. Is the light battery really a polymer battery? Below, we have dismantled one of these batteries and verified it. (Removing the battery core is a very dangerous job. If it is not properly operated, there may be dangers such as explosion and burning. Please do not imitate it.)
Hands-on disassembly of 18650 batteries
The Samsung battery is a good quality product in the 18650 battery. Below, we will disassemble it with a 18650 battery. By observing its internal structure, we can easily understand the working principle of the 18650 battery. Again, it is dangerous to disassemble the battery. Please do not imitate it to avoid danger.

Samsung battery


Samsung battery
The most common shape of the 18650 battery is the one shown above, similar to the No. 5 battery, but the volume is larger than the No. 5 battery. As the name suggests, the 18650 cell has a diameter of 18mm and a length of 65mm, making it easy to identify. For safety reasons, a gray insulating sheet is usually placed at the positive position of the battery.

Small "parts" on the battery


Battery positive


Battery negative
After disassembling it, we found that the cylindrical 18650 battery core uses an all-metal outer casing, which can better protect the internal materials and prevent leakage. The inside is a roll of film, and the positive and negative electrodes are respectively designed on both ends of the cell. The inner film is a specially formed polymer film, which is designed with a microporous structure to allow lithium ions to pass freely.


Internal soaking electrolyte


Film connected to the positive electrode


18650 battery core interior


Battery negative


Battery negative
A white plastic film is also interposed between the positive and negative electrodes of the battery. The film is soaked in the electrolyte, but the moisture is not large, the volatility is particularly good, and there is a pungent smell. The electrolyte inside the 18650 cell usually uses a lithium carbonate solvent of lithium hexafluorophosphate. The charging and discharging process of the lithium ion battery is simply a process of lithium ion intercalation and deintercalation. The amount of lithium ions embedded directly affects the capacity of the battery.
Through the above disassembly, we can find that the 18650 battery consists of five parts: the outer casing, the positive electrode, the negative electrode, the film and the electrolyte. They all perform their duties to ensure the normal charging and discharging of the user.
Hands-on disassembly of "polymer" batteries
After removing the 18650 battery, let's take a look at the "polymer" battery that is ready. From the appearance point of view, this battery core is thin and has a rectangular flat shape, and is covered with a silver insulating protective layer, and the whole is tightly closed. Next, let's disassemble it.

"Polymer batteries


"polymer" cell internal structure
After opening the outer insulating layer, we can find that it is a piece of wet block material, continue to open it, and found that it is also composed of a layer of film. Again, this material exudes a very pungent smell.



Battery pole


film
After the inner film is completely opened, the two poles of the cell are respectively connected to two layers of copper foil-like film, and a white plastic film is formed between the films. I believe that you can conclude that this "polymer" battery is also composed of: insulating shell, positive electrode, negative electrode, electrolyte and film. In addition to the outer casing and shape, this battery is no different from the ordinary 18650 battery. The real polymer cell, the internal use of solid electrolyte, the difference is very obvious.
Soft pack lithium ion battery debut
Through the above two dismantling, we can see that in fact, many products on the market that claim to use "polymer" batteries, in fact, only use 18650 batteries that look like polymer batteries, for such batteries We call it a soft lithium battery. Compared with the 18650 battery, the soft-pack lithium battery has the characteristics of being thinner and more beautiful, and has not been greatly improved in terms of security.

Soft lithium battery
What you need to know is that during normal use, the 18650 batteries that are exploding are generally inferior batteries. The safety of regular lithium-ion batteries is actually quite good. The main reason for the explosion of lithium batteries is that the batteries whose quality is not good are prone to internal short circuit during use. When an internal short circuit occurs, high temperature and high pressure gas will be generated in a short time, and it is too late to be released through the exhaust valve. An explosion will occur. In this regard, the performance of the soft-pack lithium battery is still very good, it is easier to discharge the gas than the metal shell, and even if an explosion occurs, the power will be much smaller.

Cheap and low-cost three batteries


Multi-purpose disassembled electromechanical core
When consumers buy mobile power, they should not buy some products that have no brand and the price is far below the market price. Because lithium batteries are also calculated with their own actual finished products, those mobile phones that are inexpensive and surprisingly bottom. It is very likely that some three batteries, recycled batteries or discarded batteries are used. Such batteries have serious safety hazards and have no service life.
Summary: Consumers are often misled by promotional advertisements when purchasing mobile power. For the types of mobile power batteries, we really have no way to identify them without dismantling. You only need to know, regular The batteries used by the manufacturers are basically safe and reliable products. Whether it is 18650 batteries or soft-packed lithium-ion batteries, as long as you use them correctly, you can basically use them with confidence.