Research Project New Production Process Allows Megawatt Electricity Storage System
With demand for energy storage solutions rising rapidly in connection with the transition to renewables, a joint research project is developing a electricity storage system, which allows industrial use and power outputs in the two- to three-digit megawatt range. Have a read about the details.
Essen/Germany – The aim of the companies Thyssenkrupp, Centroplast and Eisenhuth along with the research institutes Energie-Forschungszentrum Niedersachsen (EFZN) and Zentrum für BrennstoffzellenTechnik (ZBT) is to develop a new, low-cost process to manufacture one of the core components of redox flow batteries — bipolar plates — with surface areas in the m² range. Germany’s Ministry for Economic Affairs and Energy (BMWi) is providing 3.9 million euros over a period of three years as part of its funding measure “Extruded plate — new large-area bipolar plates produced by extrusion for redox flow batteries”.
The new technology will substantially reduce the unit manufacturing costs of redox flow batteries and is expected to be marketed by Thyssenkrupp from 2018.
From Watts to Megawatts
The special feature of redox flow batteries is that they do not store and convert energy in the same place, as is the case with other battery systems, but separately. Redox flow batteries store electricity as chemical energy in two large tanks containing electrolytic fluids — salts dissolved in organic or inorganic acids. The two tanks are connected to electrochemical cells that convert electricity into chemical energy or chemical energy into electricity. The power output and the amount of electricity stored can be scaled independently.
Alongside their long lifetime this is one of the major advantages of redox flow batteries over other battery systems. Redox flow batteries are particularly suitable as stationary energy storage systems. They can respond very quickly to the supply situation, switching from storage to discharge in fractions of a second with efficiency levels currently of up to 80 percent.
The bigger the tanks, the more electricity can be stored. Power output, however, depends on the size of the active area of the electrochemical cells, and thus directly on the size of the bipolar plate. Increasing this size is the aim of the consortium. The latest commercial redox flow batteries have a cell area of roughly 0.1 m², providing only around 80 watts of power. To allow large scale industrial use in the future, the active cell area of redox flow batteries is to be increased to 2.7 m², more than 30 times the current size. Connecting hundreds or thousands of cells into larger units will provide batteries producing tens to hundreds of megawatts. This principle is not new and is already implemented today in other electrolysis applications, for example in chlorine production.