Comparison of 18650 lithium battery and polymer battery

The so-called polymer lithium battery refers to a lithium battery that uses a polymer as an electrolyte, which can be divided into semi-polymer and all-polymer in detail. Semi-polymer refers to coating a layer of polymer (usually PVDF) on the isolation membrane to make the cell's adhesion stronger, the battery can be made harder, and the electrolyte is still a liquid electrolyte. The all-polymer refers to the use of polymer to form a gel network inside the cell, and then inject the electrolyte to form an electrolyte. Although all polymer batteries still use liquid electrolyte, the amount is much smaller, which greatly improves the safety performance of lithium batteries. As far as I know, only SONY is currently mass producing all-polymer lithium batteries. From another aspect, polymer battery refers to the use of aluminum-plastic packaging film as the outer packaging of lithium batteries, also commonly known as soft-pack batteries. This kind of packaging film is composed of three layers, namely PP layer, Al layer and nylon layer. Because PP and nylon are polymers, this kind of battery is called polymer battery. 1. The international price of the lower 18650 is about 1USD/pcs. If calculated according to 2Ah, it is about 3RMB/Ah. The price of polymer lithium battery is 4RMB/Ah for low-end copycat factories, 5~7RMB/Ah for mid-range, and 7RMB/Ah for mid-to-high end. Like ATL and Lishen, they can generally sell for around 10RMB/Ah, and you are not willing to pick them up when your order is small. 2, can not be customized SONY has always wanted to make lithium batteries the same as alkaline batteries, there is a certain industry standard, just like the 5th battery, the 7th battery, basically the same all over the world. However, a major advantage of lithium batteries is that they can be designed according to customer needs, and there is no uniform standard. So far, the lithium battery industry basically only has a standard model of 18650, and the others are based on customer needs. Designed. 3. Poor safety. We know that under extreme conditions (such as overcharge, high temperature, etc.), lithium batteries will have a violent chemical reaction inside and a large amount of gas will appear. The 18650 battery uses a metal shell with a certain strength. When the internal pressure reaches a certain level, the steel shell will break and explode, causing a terrible safety accident. This is why the room where the 18650 battery is detected generally has to be protected by layers, and no one can enter during the detection. Polymer batteries do not have this problem, even in extreme cases, due to the low strength of the packaging film, as long as the air pressure is slightly higher, it will break and will not explode. The worst case is combustion. So in terms of safety, polymer batteries are better than 18650 batteries. 4. Low energy density A typical 18650 battery has a capacity of about 2200mAh, so that the energy density is about 500Wh/L, while the energy density of polymer batteries is currently close to 600Wh/L. But polymer batteries also have their own shortcomings. The most important thing is that the cost is high. Since it can be designed according to customer needs, the research and development costs must be included. In addition, the variety of shapes and types have resulted in non-standard parts of various tooling and fixtures in the manufacturing process, and correspondingly increased costs. The polymer battery itself has poor versatility, which is also brought about by flexible design, and it is often necessary to design a new one for customers for the difference of 1mm. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete it. Previous: Do you want to activate the new lithium battery?