The key point to reduce the occurrence of thermal runaway of lithium-ion batteries

　　For lithium batteries, thermal runaway is the most serious safety accident.

　　In essence, "thermal runaway" is a positive energy feedback cycle: increased temperature will cause the system to heat up, and the system will heat up and increase the temperature, which in turn makes the system hotter.

　　For the battery cell, its safety and thermal control ability are not only related to the positive electrode material, but also have a lot to do with other components such as the negative electrode, the separator, the electrolyte, and the binder.

　　1. Cathode material

　　In the case of overcharge, the decomposition reaction of the positive electrode and its reaction with the electrolyte will release a lot of heat. Therefore, the positive electrode material needs to have good compatibility and stability with the electrolyte.

　　2. Anode material

　　The methods to improve the thermal stability of the negative electrode material mainly include reducing the specific surface area of the negative electrode material and improving the thermal stability of the SEI film.

　　3. Diaphragm

　　It is best to use a type that has high thermal stability, high temperature resistance, flame retardancy and fire resistance, and can maintain its structural integrity even at a high temperature of 700°C.

　　4. Electrolyte

　　The electrolyte is a flammable organic carbonate, so it is very important to improve the safety of the electrolyte.

　　5. Conductive agent and binder

　　The type and quantity of the conductive agent and the binder also affect the thermal stability of the battery. The binder reacts with lithium ions at high temperatures to generate a large amount of heat, and different binders generate different amounts of heat.

　　Avoiding the occurrence of thermal runaway not only requires changes in materials, but also needs to strengthen the battery formula design, structural design and thermal management design of the lithium battery pack to reduce the possibility of thermal runaway.

　　Lithium-ion battery (LIB) has become the main energy storage solution in modern social life. Among them, lithium iron phosphate batteries are a perfect replacement for lead-acid batteries, and they are the first choice for grid-connected peak shaving, off-grid energy storage, photovoltaic energy storage, UPS, data center and other industries.