Flow batteries rely on chemistry to do their work, but that’s where the link to the batteries in our devices ends. The first major difference is flow batteries have not one, but two electrolytes. We share the inner secrets of flow batteries in more detail in this post. By the time you have finished reading through, you should have a basic understanding of how flow batteries work.
The Big Secrets Inside Flow Batteries
A flow battery, in its basic form, comprises two sets of chemicals dissolved in water, and held in two separate tanks. Pumps circulate these electrolyte liquids through a small central tank, where a chemical reaction takes place.
A membrane in that central tank keeps the liquids apart, so they cannot contact each other. However, the membrane does allow the active ions to exchange, generating the energy we call electricity. This is the next of the inner secrets of flow batteries to know.
The fundamental difference between a flow battery, and a conventional electro-chemical cell, is that flow batteries store their energy in liquid electrolytes. Whereas the batteries we know in our devices and vehicles, store their energy in their solid electrodes.
There are two ways to recharge a flow battery, depending on the individual design. The first of these methods involves replenishing the liquid electrolytes, as is the case with fuel cells. The second method uses an external electricity source, that regenerates the existing liquids.
Applications for These Flow Devices
Flow batteries have certain advantages over conventional batteries. They offer long operating lives, and extended times between recharging. However, flow batteries have lower cycle energy efficiency, meaning they deliver more reduced energy than it takes to recharge them.
Flow batteries have great potential for large scale storage of renewable wind and solar energy. They therefore could deliver valuable service through balancing grid loads, and managing spikes in demand peaks. At this stage though, they are only starting to make real inroads.
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