Storage of Electric Energy

It is generally agreed that storage of electric energy is much more difficult than that of thermal energy. It is commonly employed the storage battery. The superconductor energy storage is under the research.

The invention of plumbous acid storage battery in the worldwide has its roots tracing back to 100 years ago, which realized its electricity charging and discharging by use of the reversible transfer between chemical energy and electric energy. The plumbous acid storage battery is lower in price, but short in operation life, heavy in weight and maintenance needed frequently. The innovative plumbous acid storage battery has been developed successfully required less maintenance, making the performance improved incrementally. Right now, energy storage devices associated with photovoltaic generation system are mostly employed the plumbous acid storage battery.

In 1908, the innovative Nickel-Cadmium, Nickel-Iron alkaline storage battery was invented, which was convenient for maintenance with long service life, light weight, but higher in price resulting in the operation condition of small storage capacity.

The existing storage battery is lower in energy storage density, which cannot satisfy the requirement of larger capacity and long time storage. Newly developed storage batteries include silver-zinc cells, lithium cells and natrium-sulfur cells.

Some type of metal or alloy can be transferred to superconductor under the extreme lowest temperature. In theory, electric energy can be stored limitlessly in a time period in a superconductor winding without any resistance. This super-conducting storage can directly store the electric energy without any requirement of energy conversion, with high efficiency and quick initiation and can be installed in any places, notably around the consumption center without any pollutant emission. But the enabling technologies are not mature and required to continuing its research and development.