First of all, from the structural point of view, the full name of lithium-ion polymer battery should be lithium-ion polymer battery, so it seems that lithium-polymer battery is actually a kind of lithium-ion battery. But the biggest difference between the two is that the electrolytes used inside the lithium-ion batteries are different. Lithium-ion batteries use liquid electrolytes, while polymer lithium-ion batteries are replaced by solid polymer electrolytes, which can be solid or semi-solid (colloidal).

Secondly, in terms of appearance, most of the mobile power supply sold on the market at present uses cylindrical (18650) lithium-ion batteries or block lithium polymer batteries. So when we select the mobile power supply, if the product packaging does not specify the type of battery used, then we can simply get a general understanding of the type of battery used inside the product through the thickness of the product itself.

It can be said that after years of development, the technology of lithium-ion batteries has been relatively mature, and large-scale production has made its manufacturing cost very low. So lithium-ion batteries have more advantages in price than lithium-polymer batteries. This is why most notebook computers and other devices currently use this kind of core.

In order to avoid explosion of sealed metal case, the 18650 battery is usually equipped with a safety valve at the top. When the internal pressure of the battery is too high, the top safety valve will automatically pop up to reduce pressure. However, when the safety valve pops up, the lithium ion leaked from the battery will still ignite due to the contact with oxygen in the air.

Compared with lithium-ion batteries using liquid electrolyte, lithium-polymer batteries using solid polymer electrolyte have the characteristics of ultra-thin shape, theoretical minimum thickness of 0.5mm, arbitrary shape and arbitrary area. It greatly improves the flexibility of battery modeling, so that it can be better made into a new generation of lithium batteries of any shape and capacity.

Therefore, for the electronic products using this lithium ion core, there are very high requirements on its internal charge and discharge protection IC. However, with the development of lithium-ion batteries for many years, both the design of batteries themselves and the technical level of various protective IC have been very mature. As long as we can use the batteries correctly in daily use and avoid the phenomenon that the batteries are pierced by hard objects, 18650 batteries are still very safe, otherwise most notebooks on the market will not use such batteries.

If in a strict sense, lithium polymer batteries are the same as lithium ion batteries using liquid electrolyte in positive, negative and electrolyte, and their working principle, the only difference is the difference in the diaphragm and packaging materials. Therefore, lithium polymer batteries are also a kind of lithium ion batteries fundamentally.

Summary: In fact, both steel-shell lithium-ion batteries and soft-packed lithium-ion batteries have excellent safety performance. After all, the production technology of lithium-ion batteries has been very mature. As long as high temperature, short circuit, overcharge and piercing are avoided in daily use, accidents such as explosion and ignition can be avoided. For lithium-ion batteries and lithium-polymer batteries, they have their own advantages and disadvantages. If they are more cost-effective, they should choose 18650 batteries. If they are more inclined to the appearance and volume of mobile power supply, then the lithium-polymer batteries with a slightly higher price are preferred.