Detailed explanation of the principle, advantages and disadvantages of polymer lithium batteries

There are currently two types of lithium batteries: liquid lithium batteries (LIB) and polymer lithium batteries (PLB). Among them, the liquid lithium battery refers to a secondary battery in which Li+ intercalation compounds are positive and negative electrodes. The positive electrode adopts the lithium compound LiCoO2, LiNiO2 or LiMn2O4, and the negative electrode adopts the lithium-carbon interlayer compound LixC6. The typical battery system is: the principle of polymer lithium battery is the same as that of liquid lithium, but the important difference is that the electrolyte is different from liquid lithium. The essential structure of the battery includes three elements: positive electrode, negative electrode and electrolyte. The so-called polymer lithium battery means that at least one or more of these three critical structures use polymer materials as the critical battery system. In the polymer lithium battery system currently developed, polymer materials are mainly used in the positive electrode and electrolyte. Cathode materials include conductive polymer or inorganic compounds commonly used in lithium batteries. The electrolyte can use solid or colloidal polymer electrolytes, or organic electrolytes. Generally, lithium ion technology uses liquid or colloidal electrolytes, so it must be strong The secondary packaging to contain the flammable active ingredients, which adds weight and also limits the flexibility of size. The new generation of polymer lithium batteries can be thinner in shape (the thinnest ATL battery can reach 0.5 mm, which is equivalent to the thickness of a card), arbitrary area and arbitrary shape, which greatly improves the battery shape design Flexibility, so that it can be made into batteries of any shape and capacity according to product requirements, and provides equipment developers with some design flexibility and adaptability in power processing methods to maximize their product performance. At the same time, the unit energy of the polymer lithium battery is 20% higher than that of the current general lithium battery, and its capacity and environmental protection performance are all improved compared with the lithium battery. Advantages and disadvantages of polymer lithium batteries: Advantages: 1. The operating voltage of the single battery is as high as 3.6v~3.8v, which is much higher than the 1.2V voltage of nickel-hydrogen and nickel-cadmium batteries. 2. Large capacity density, its capacity density is 1.5~2.5 times of Ni-MH battery or Ni-Cd battery, or higher. 3. The self-discharge is small, and its capacity loss is also small after being left for a long time. 4. Long life, the cycle life can reach more than 500 times in normal use. 5. There is no memory effect, no need to empty the remaining power before charging, easy to use. 6. Good safety performance. The polymer lithium battery adopts aluminum-plastic soft packaging in structure, which is different from the metal shell of the liquid battery. Once a safety hazard occurs, the liquid battery is easy to explode, and the polymer battery will only be air-swelling at most. 7. The thickness is small, which can be made thinner and ultra-thin, and the battery can be assembled into a credit card. Generally, liquid lithium batteries adopt the method of customizing the shell first, and then plugging the positive and negative materials. The thickness is below 3.6mm, and there is a technical bottleneck. Polymer batteries do not have this problem. The thickness can be below 1mm, which is in line with the current mobile phone demand. . 8. The battery with light weight and polymer electrolyte does not need a metal shell as a protective outer packaging. The weight of the polymer battery is 40% lighter than the steel shell lithium battery of the same capacity specification, and 20% lighter than the aluminum shell battery. 9. Large-capacity polymer batteries have a capacity of 10-15% higher than steel-shell batteries of the same size and 5-10% higher than aluminum-shell batteries. They have become the first choice for color-screen mobile phones and MMS mobile phones. Color screens and MMS are newly released on the market. Most mobile phones also use polymer batteries. 10. Small internal resistance. The internal resistance of polymer batteries is smaller than that of ordinary liquid batteries. At present, the internal resistance of domestic polymer batteries can even be less than 35m, which greatly reduces the self-consumption of the battery and extends the standby time of the mobile phone. In time, it can fully meet the international standards. This kind of polymer lithium battery that supports large discharge current is an ideal choice for remote control models, and has become the most promising product to replace Ni-MH batteries. 11. The shape can be customized. Manufacturers are not limited to standard shapes, and can be economically made into suitable sizes. Polymer batteries can add or reduce the thickness of battery cells according to customer needs, and develop new battery cell models. They are cheap and have a short mold opening cycle. Some can even be tailored to the shape of the mobile phone to make full use of the battery shell space and improve battery capacity. 12. Good discharge characteristics. Polymer batteries use gel electrolyte. Compared with liquid electrolyte, gel electrolyte has stable discharge characteristics and a higher discharge platform. 13. The design of the protection board is simple. Because the polymer material is used, the battery core does not fire or explode, and the battery itself has sufficient safety. Therefore, the protection circuit design of the polymer battery can consider omitting the PTC and fuse to save battery cost. Disadvantages: 1. High battery cost, difficult to purify electrolyte system. 2. To protect the circuit control, overcharge or overdischarge will destroy the reversibility of the battery's internal chemical substances, which will seriously affect the battery's life. 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.