VisBlue - What Is a Redox Flow Battery?
Energy storage - different technologies
Energy storage is becoming a more necessary good in our daily lives and increasingly in the near future. Whether it is to power our vehicles and phones, to utilise the energy that comes from renewable energy sources on a wind-still, cloudy day, or for server backup, we are becoming more and more reliant on batteries.
However, we have come to expect that batteries wear out and are being replaced in few years, only to dispose of old batteries.
Should it be this way?
The problem stems from the fact that conventional batteries deteriorate over time, whether they are used or not. They have a limited number of charge/discharge cycles, before they eventually need to be disposed of.
With redox flow batteries you can alleviate this issue. The technology allows for more charge/discharge cycles, and for a VisBlue Battery Solution, the life expectancy will be equal to that of a PV-system. Moreover, with VisBlue’s redox flow technology, the electrolyte will not deteriorate, and the battery is 100% recyclable.
What is a redox flow battery?
Redox flow batteries are a type of battery that differs from other battery types. It is made up of two tanks filled with electrolyte-fluids and what is called a stack. The stack is comprised of several stack cells, each with a frame, bipolar plate and a membrane. The number and size of the stack cells depend on the power output needed. The size of the tanks determines the capacity of a battery. The fluid in the two tanks acts as cathode (positive electrolyte) and anode (negative electrolyte). Just like a regular battery.
The cathode and anode can consist of the same or different types of solution with relatively high electrical properties. In addition to this, the electrolytes in a redox flow battery has different possible oxidation levels, which is a crucial chemical property when storing energy in a redox flow battery.
In VisBlue’s redox flow battery both tanks hold a solution of sulphuric acid with a unique vanadium solution in it. The only differences between the two tanks is that one side contains negative electrons and a reduced oxidation level, and the other side contains positive electrons and an increased oxidation level.
How does a redox flow battery work?
In a redox flow battery, you have two separated flow systems; one for the anode and one for the cathode. With the help of pumps, the electrolyte flows from the containers through pipes, and through the cell stacks. Even though, there are two separate flow systems, the membrane divides and distributes negatively and positively charged protons in their respective tanks. Over time, cross-contamination of the electrolytes will occur. With two different electrolytes in each tank, this cross-contamination causes the battery efficiency to degrade. With the same electrolyte in each tank it is possible to avoid cross-contamination.
What does redox mean?
The term redox in redox flow refers to redox-reaction, which is the description of the change in oxidation level of a chemical: reduction and oxidation. In this process electrons are transferred from one element to another.
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