The security problem of power bank has always been a concern of consumers. How to distinguish between genuine and anti-counterfeit power bank is something that everyone has been concerned about. Let's teach you the difference between polymer battery and lithium-ion battery to distinguish between authenticity and authenticity.
When you buy power bank, you will usually see what type of battery this product uses in the product introduction. At present, the most common batteries on the market are basically divided into three types: polymer batteries, lithium ion batteries and lithium iron phosphate batteries. Among them, the most widely used is lithium-ion batteries, which are inexpensive.
Because polymer safety is superior to lithium-ion batteries and the price is lower than that of lithium iron phosphate batteries, many users prefer to use polymer batteries. At present, there are many power bank sources on the market that claim to use polymer batteries. In fact, most of the products used in the interior are actually soft-packed lithium-ion batteries, so the difference between lithium-ion batteries and polymer batteries is Where is it?
The technicians have tested the disassembly of many power bank sources. Among these products, there are 18,650 batteries, and some "polymer batteries", which are disassembled and analyzed from the internal structure of the polymer. The difference between a battery cell and a lithium ion battery cell. The conclusion is drawn: the appearance is fake and the thickness of the fuselage is thin. The biggest difference between the polymer battery and the ordinary 18650 battery is the appearance. The ordinary 18650 battery is similar to the No. 5 battery, and the polymer battery has better plasticity and can be made into any area and any shape. The theoretical thickness is as thin as 0.5mm, making the power bank supply look slimmer overall and lighter in weight, which improves portability.
The internal structure of the fake polymer battery:
We cut the film that was prepared outside the cell, the texture of the film is tough, the interior is silver, and it has a strong chemical syrup. Obviously, the true identity of this "polymer cell" is actually a soft-packed lithium-ion battery. Below, let us look at the reasons for this judgment in detail.
Soft pack lithium ion battery:
After opening the film, we can see that there is some liquid on the film and the internal cells, and these liquids will quickly evaporate. The inner cell is divided into many layers, the outer layer is silver foil, the inner layer is a copper foil with a plastic film, and the aluminum foil layer and the copper foil layer are respectively connected to the two poles of the battery core.
Both polymer cells and lithium-ion cells are composed of many layers of folds, but the biggest difference is the electrolyte used inside. Lithium-ion batteries use a liquid electrolyte inside. When the battery is squeezed, "water" is produced, while inside the polymer battery, a solid or semi-solid (gel) electrolyte is used, and the density is higher. The capacity is also larger.
Working principle and safety:
First of all, let us briefly explain the working principle of lithium-ion batteries. Lithium-ion battery charging and discharging is simply the transfer of lithium ions between the positive and negative electrodes, that is, through the two processes of embedding and deintercalation. At the time of discharge, lithium ions are carried out from the positive electrode, and the electrolyte enters the negative electrode like water, and this process is called deintercalation. When charging, this process is just the opposite, that is, embedded.
In terms of safety, in the process of using ordinary lithium-ion batteries, if the internal temperature is too high, there is a danger of explosion, and the polymer battery will only produce chemical volatilization, and at most, combustion will occur. It will not explode. Soft-packed lithium-ion batteries and polymer batteries use aluminum-plastic composite casings, so when the charging time is too long, the temperature will be too high or the internal pressure will be too large, they will expand, and the safety is relatively better.
In general, whether it is a metal shell of 18650 batteries or soft-packed lithium-ion batteries, the cost is relatively dominant, and the production technology is relatively mature, occupying the largest share in the market, if it is a regular manufacturer of lithium ions The battery core is normally not subject to explosion and other dangers. The characteristics of polymer batteries are that they are more diverse. If they are also large-capacity, the portability of polymer cells will be relatively better. The most important advantage is that there will be no explosion.
In fact, in the end, according to the choice of consumers, from the perspective of cost-effective considerations, choose the ordinary 18650 batteries or soft-packed lithium-ion batteries; from the safety point of view, do not pay attention to the price itself, polymer batteries It is the best choice.