By adding functional additives, using new lithium salts and novel solvents, the safety hazards of lithium-ion battery pack electrolytes can be solved.

According to the different functions of the additives, they can be divided into the following categories: protective additives, film-forming additives, protective additives for positive electrodes, stabilizing lithium salt additives, lithium precipitation additives, collector anticorrosive additives, and enhancement of the wettability additives.

In terms of solvent, many researchers have put forward a series of new organic solvent, such as antelope acid esters, organic ethers. In addition, ionic liquid also has a class of electrolyte with high safety, but compared with the commonly used carbonate electrolyte, the viscosity of ionic liquids is higher by one order of magnitude and the conductivity and ion self-diffusion coefficient are lower, so there is still a lot of work to be done before it can be put into practical use.

2. Enhance the safety of electrode materials

Lithium iron phosphate battery packs and ternary composite materials are considered as low-cost and safe positive electrode materials, which may be widely used in the electric vehicle industry. A common method to enhance the safety of anode materials is coating modification, such as using metal oxides to coat the surface of the anode materials, which can prevent direct contact between the anode materials and the electrolyte, inhibit the phase transition of the anode materials, enhance their structural stability, and reduce the disorder of cations in the lattice to reduce the heat production of side reactions.

Regarding cathode materials, enhancing the thermal stability of SEI films is a key method to enhance the safety of cathode materials, as their surface are often the part that is prone to thermochemical decomposition and heat release in lithium-ion batteries. The thermal stability of cathode materials can be enhanced through weak oxidation, deposition of metals and metal oxides, polymer or carbon coating.

3. Improve battery protection design

In addition to enhancing the safety of battery materials, setting battery safety valves, hot melt fuses, connecting components with positive temperature coefficients in series, using thermal sealing separator, loading protection circuits, battery management systems, etc, can also enhance safety.