How to improve the safety performance of single cells?

How to improve the safety performance of single cells? Although the safety of lithium battery cannot be cured, it is controllable and preventable. Facing it correctly and actively exploring some new safety technologies will help promote the progress of battery technology, such as improving the thermal stability of materials/interfaces, and developing self-excited monomers. Thermal protection technology and system thermal expansion prevention technology can effectively improve the safety of the battery system. The following is Professor Ai Xinping's research on battery cell safety for readers' reference. Surface coating. The thermal decomposition of the positive electrode and the oxygen evolution caused by it are important in its reaction with the interface (electrolyte), so we can cover the active surface of the positive electrode with a thermally stable protective layer. For example, after coating a phosphoric acid film or lithium phosphate on the surface of a high-nickel positive electrode, the direct contact between the high-nickel material and the electrolyte can be reduced, thereby reducing the intensity of side reactions and heat generation. Common coating materials include phosphates, oxides, fluorides, and can also be some polymers. Construct a concentration gradient. The high nickel cathode is unsafe. In addition to its poor thermal stability, it is more important that nickel is very useful for the oxidation and decomposition of the electrolyte, and the material itself does not emit that much heat, but after adding the electrolyte, Its heat production temperature and heat production are sharply increased, the reason is that the interface reaction of the electrolyte accounts for a large part. If we take high nickel as the core and use some materials with low nickel content as the shell, let it have a concentration gradient inside and outside, which will help reduce the reactivity of the material interface and improve the safety of the battery. Preventing the induction and spread of thermal runaway is the focus of work. Although Professor Ai Xinping has analyzed a variety of ideas to improve the safety of single cells, as mentioned above, we have not been able to guarantee the removal of all hidden safety hazards from the process. Instead of doing too much entanglement at the technological level of the cell, it is better to focus on the system level, that is, to prevent system dysfunction or even catastrophic accidents after thermal runaway occurs in the monomer. Ouyang Minggao, executive vice chairman of the Electric Vehicle Association of my country, also said that it is not realistic for lithium batteries to completely prevent thermal runaway from the monomer level, but we can prevent induction and spread from the thermomechanical design and control design of the battery system. , Even if the single body is out of control, there will be no accident. Statement: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete the previous article: What are the benefits of ternary lithium batteries?