When we charge a flow battery, we reverse the chemical changes that took place as it discharged electricity. Charging begins as electricity from an outside source enters the system. This power could come from the electricity grid, solar panels, or another power source.
Electricity Drives Chemical Reactions In The Flow Battery
The inbound electricity drives chemical reactions inside the battery cell. These reactions change the electrolytes into a higher-energy state.
The twin electrolytes are separate as they pass through the cell. A special membrane between them allows certain ions to pass through, while preventing the two liquids from mixing directly.
The Electrolytes Gradually Return To Their Charged States
As we charge the flow battery, the chemical materials in the electrolytes gradually convert back into their charged forms. These liquids then carry this stored chemical energy back to their tanks.
This is one of the most useful features of a flow battery. The battery does not need to store its energy inside the cell itself. Instead, the charged electrolytes can remain in their tanks until the stored energy is needed.
The Amount Of Energy Charged Depends On The Electrolyte
The amount of energy stored depends on how much charged electrolyte is available. Larger tanks can therefore provide more energy storage without requiring a complete redesign of the battery cell.
When The Charging Is Over The Electrolytes Are Ready
When the charging process is over, the electrolytes are ready to pass through the cell again. The stored chemical energy can then be converted back into electricity.
A flow battery can therefore be thought of as an energy storage system that repeatedly changes electricity into chemical energy, and then changes it back again.
We Can Charge A Flow Battery As Many Times As We Like
We can repeat this charging process repeatedly. This makes flow batteries particularly interesting for storing electricity generated at different times, from when it is actually needed.
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