Energy storage involves a wide range of fields. According to the forms of energy involved in the energy storage process, energy storage technology can be divided into physical energy storage and chemical energy storage. Physical energy storage is the storage of energy through physical changes. It can be divided into gravity energy storage, elastic energy storage, kinetic energy storage, cold energy storage, superconducting energy storage and super capacitor energy storage. Among them, superconducting energy storage is the only technology that directly stores current. Chemical energy storage is to store energy in substances through chemical changes, including secondary battery energy storage, liquid flow battery energy storage, hydrogen energy storage, compound energy storage, metal energy storage, etc. electrochemical energy storage is the general term of battery energy storage.

When renewable energy has become the mainstream of the market, energy security has become a new challenge. Whether it is the safety and energy density of energy storage technology after large-scale expansion, or the possibility of secondary disasters caused by energy storage configuration after disasters, the existing energy storage technologies have not reached the level of undertaking super large-scale strategic energy reserves. From the perspective of energy density, the most probable direction of super large-scale energy storage technology in the future is pure chemical energy storage, such as hydrogen energy storage, methanol energy storage, metal energy storage, etc. Large energy companies have certain resource advantages in the development of large-scale energy storage technology, which can undertake most of the energy security tasks.