MIT develops utility scale liquid batteries
One of the problems with large scale renewable energy is the cost of batteries for storing electricity. Storage is needed because wave, wind, and solar energy all have down times when the water is calm, no wind blows, and when the sun goes down. The cost of batteries for utility scale projects is extremely expensive. MIT professor Donald Sadoway has come up with a way to counter those problems by building a liquid battery.
Sadoway’s batteries are different from any other battery in a number of ways. First, all of the components of the battery are liquid. Some batteries do have one component that is liquid but not the entire battery. Secondly this battery is not intended for use in small electrical devices or cars. Third, this battery is designed to be stationary and very large in order to handle utility scale renewable energy storage. Lastly, the batteries will use low cost easy to find metals.
Because storage devices used by utilities are never transported or used by consumers, many safety features won’t be required. For instance the battery doesn’t need to be “crash worthy” or “idiot proof”. Small batteries won’t be linked together to create enough storage. Instead this battery will be built large enough to handle the amount of electricity that needs to be stored by utility size projects.
The battery uses two liquid metals (not disclosed for patent reasons) and a layer of salt as components. Because the metals must be kept in a liquid state, the entire battery is kept at the very high temperature of 700 degrees Celsius. Keeping large scale versions at this temperature won’t be a problem because of the amount of electricity going in and out of the battery will be enough to sustain the temperature. For the smaller models used in the lab for testing, an outside heater must be used.
In order to bring the cost of renewable energy down to a competitive level with fossil fuels, Sadoway’s batteries must do more than just use cheap abundant materials. He has said that his batteries “must be cheap to build, cheap to maintain, last a long time with minimal maintenance, and store enormous amounts of energy.”
The funding for Sadoway’s research comes from several sources: ARPA-E (Advanced Research Projects Agency, Energy), the Deshpande Center and the Chesonis Family. The French oil company Total has partnered with MIT to develop a liquid battery that would be used in homes or other buildings.
Sadoway is currently testing different combinations of metal alloys to find which ones work the best together. After the optimum metal alloy components are found there are still several other pieces of the battery that must be developed and tested such as "how to design and build the necessary containers, electrical control systems, and connections.”
Developing utility scale cost effective batteries is something of a crusade for Sadoway. As he says, ““I’m not doing this because I want another journal publication. It’s about making a difference … It’s an opportunity to invent our way out of the energy problem.”
