The important energy storage batteries used in the power grid include lead-acid batteries, sodium sulfur batteries, and liquid flow batteries. The principle is to convert electrical energy into chemical energy for storage, and then convert chemical energy into electrical energy for use when necessary. Lead acid batteries have been developed and used for a relatively long time, and their technology is also relatively mature. They have gradually entered the stage of being mainly sealed maintenance free products, with lower costs and moderate energy density among various types of batteries. In terms of environmental impact, lead-acid batteries based on sealed valve control also have high operational reliability, but their energy density is relatively average, and their disadvantages are not very obvious.

However, compared to lead-acid batteries, sodium sulfur batteries and flow batteries have advantages that other chemical batteries do not have:

1) The storage capacity is even larger, reaching hundreds of kilowatts or even megawatts, which is 8-10 times that of ordinary batteries;

2) Sodium sulfur batteries and liquid flow batteries are pollution-free and will not have an impact on the environment;

3) Long service life and good stability.

The disadvantage is that the working environment requires high temperatures, ranging from 300 ℃ to 500 ℃, and the technology still needs further improvement.