How to increase the volumetric energy density of lithium batteries?

How do lithium battery manufacturers interpret how to increase the volumetric energy density of lithium batteries? Taking lithium batteries as an example, they have advantages in terms of volumetric energy density and have the potential and prospect of becoming the mainstream technology of power lithium-ion batteries, but the bottleneck is that the safety of high-energy-power lithium-ion batteries is relatively low. Some people questioned the development route of power lithium-ion battery technology due to safety issues. 1. Thin the shell, current collector, diaphragm, increase the compaction density of the electrode, reduce the amount of binder and conductive agent used, and increase the content of the active material in the electrode; but the corresponding risks will be brought about: thin shell The body will reduce the safety of the battery, the current collector will easily break the electrode, and the safety of the thin separator will decrease. The new compact density of the electrode may cause the liquid absorption rate to decrease and the pole piece to become brittle. 2. Mixing high-capacity and low-pressure compaction materials with high-pressure compaction materials to form a composite material system to increase the compaction density of the composite material system. 3. Choose a positive and negative electrode material with high specific capacity or a positive electrode material with a high voltage platform. Lithium-sulfur batteries are regarded as one of the ideal choices for the next generation of high-energy density battery systems. They have received great attention from scientific research and industrial circles all over the world, and are also one of the key research directions in the future layout of various countries. However, as the research continues to deepen, Lithium-sulfur batteries are also facing increasingly severe challenges. The energy density of currently commercial lithium batteries is about 260Wh/kg and 700Wh/L. The current important problem is the low volume energy density, which causes it to lose its competitiveness in many important market applications. At the same time, the high electrolyte dosage has also become the bottleneck of its weight energy density increase. In addition, the safety and long cycle life of the metal lithium negative electrode have not been well resolved. Lithium battery has high energy density. Its volume energy density and mass energy density can reach 450Wh/dm3 and 150Wh/kg respectively. And it is still improving. There are two important reasons for the low volumetric energy density of lithium-sulfur batteries: intrinsically, the theoretical density of active materials lithium and sulfur is relatively low, lithium is 0.534g/cm3, sulfur is 2.07g/cm3, and the cobalt in lithium batteries The theoretical density of materials such as lithium oxide and ternary materials is much higher; from the electrode structure, there is another most important reason is that sulfur is an electronic and ion insulator, so sulfur should be dispersed into a large amount of conductive carbon with a high specific surface area. The problem of using a large amount of conductive carbon is that the specific surface area of u200bu200bthe entire positive electrode is very high, and the porosity is very high. Generally speaking, the porosity of the traditional carbon-sulfur positive electrode is twice that of the lithium battery positive electrode. Lithium batteries are considered by many to have basically reached the ceiling of the theoretical value of energy density. In recent years, it has been stated that the energy density of lithium monomer is 165wh/kg, and the package body is 140wh/kg. In the next two years, it is planned to increase the energy density of the monomer to more than 180wh/kg, the volume specific energy density will increase by 50%, the package body will increase to 160wh/kg, the life span will be up to 8 years and 1.2 million kilometers, and the cost can be saved by 30%. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the commonly used batteries in UPS power applications?