How to improve the safety of lithium batteries

The advantage of new energy vehicles is that they are more low-carbon and environmentally friendly than gasoline-fueled vehicles. It uses unconventional vehicle fuels as the power source, such as lithium batteries, hydrogen fuel, etc. The application of lithium-ion battery is also very wide, besides new energy vehicles, cell phones, laptops, tablet PCs, mobile power, electric bicycles, electric tools, etc.

However, the safety of lithium-ion batteries should not be underestimated. A number of accidents show that when people improperly charged, or the ambient temperature is too high, it is very easy to trigger lithium-ion battery spontaneous combustion, explosion, which has become the biggest pain point in the development of lithium-ion batteries.

Although the properties of the lithium battery itself determines its "flammable and explosive" fate, but it is not completely impossible to reduce the risk and safety. With the continuous progress of battery technology, both cell phone companies and new energy vehicle companies, through a reasonable battery management system and thermal management system, the battery will be able to ensure safety, and will not explode or spontaneous combustion phenomenon.

1.Improve the safety of electrolyte

There is a high reactivity between electrolyte and both positive and negative electrodes, especially at high temperatures. To improve the safety of batteries, improving the safety of electrolyte is one of the more effective methods. By adding functional additives, using new lithium salts and using new solvents, the safety hazards of electrolyte can be effectively solved.

According to the different functions of additives, they can be divided into the following categories: safety protection additives, film-forming additives, cathode protection additives, lithium salt stabilization additives, lithium precipitation promotion additives, collector fluid anti-corrosion additives, enhanced wettability additives, etc.

2. Improve the safety of electrode materials

Lithium iron phosphate and ternary composites are considered to be low-cost, "excellent safety" cathode materials that have the potential to be popularly used in the electric vehicle industry. For the cathode material, the common method to improve its safety is coating modification, such as metal oxides on the surface of the cathode material, can prevent direct contact between the cathode material and the electrolyte, inhibit the cathode material phase change, improve its structural stability, reduce the disorder of the cations in the lattice, in order to reduce side reaction heat production.

The negative electrode material, since its surface is often the part of the lithium-ion battery that is most susceptible to thermochemical decomposition and exotherm, improving the thermal stability of the SEI film is a key method to improve the safety of the negative electrode material. The thermal stability of anode materials can be improved by weak oxidation, metal and metal oxide deposition, polymer or carbon cladding.

3. Improve the safety protection design of the battery

In addition to improving the safety of battery materials, many safety protection measures used in commercial lithium-ion batteries, such as setting battery safety valves, thermally soluble fuses, connecting components with positive temperature coefficients in series, using thermally sealed diaphragms, loading special protection circuits, and dedicated battery management systems, are also means to enhance safety.

Post time: Feb-14-2023