Recent energy storage developments

In a recent article on the engineering website, Tom Lombardo explains about recent developments in battery technology.

 

New Battery Technology for Renewable Energy and Electric Vehicles

Energy storage is a continually evolving industry, with new devices being engineered and mature technologies undergoing refinement. Here are a few battery innovations that could give a boost to the renewable energy and electric vehicle markets.

Companies like Cambrian Innovation and Kona Brewing Company have been generating energy from brewery waste for several years. So how about an energy storage system whose main ingredient is, in a way, another “waste product” from the brewing industry?

We all know the cliché of a scientist yelling “EUREKA” after making a discovery. In this case, it was engineers at Stanford University shouting “UREA” after creating a battery that uses urea – a component of urine – as its electrolyte. When combined with electrodes made from aluminum and graphite, this battery is non-flammable, efficient, and inexpensive. Laboratory testing showed that it’s capable of delivering over 1500 charge cycles at a relatively quick charging rate.

The battery’s chemistry has an energy density of just under 100 Wh/kg, less than that of a Li-ion battery. That makes it suitable for stationary applications like grid-level or residential energy storage, but undesirable for electric vehicles and other mobile uses. That’s unfortunate since its quick charging rate would be a welcome feature in an EV battery. On the other hand, if it can charge quickly enough, the smaller capacity might not be an issue, especially if it drastically lowers the cost. Oh, and it’s non-flammable – a nice attribute of any battery!

The team is working on a commercial version of the battery – no word yet on when it might be available. If any information leaks, I’ll let you know.

On the subject of non-flammable batteries, Dr. Michael Zimmerman, Professor of Mechanical Engineering at Tufts University, examined the benefits and drawbacks of lithium-ion batteries and decided that a solid polymer electrolyte would be safer than the liquid electrolyte currently used. He developed a solid-state Li-ion battery that can be cut, punctured, and otherwise abused without causing an explosion or even a malfunction. Its plastic electrolyte is flame-resistant. In addition, the material doesn’t allow dendrites to form on the electrodes, which increases the battery’s lifespan and the number of charge cycles.

The professor’s battery is fully functional, but currently only works with small scale devices like phones. Scaling up the design for larger applications, such as renewable energy storage and electric vehicles, presents a challenge. Fortunately, Dr. Zimmerman’s company, Ionic Materials, received a $3M award from ARPA-e, which will help improve the battery’s energy density, cycle life, and manufacturability, while reducing cost.

The Australian Renewable Energy Agency (ARENA) delivered a grant for $4.1M to Ecoult, to help the company improve its flagship product. The UltraBattery, a hybrid lead-acid battery with an integrated supercapacitor, is the core technology behind Ecoult’s UltraFlex, which is currently under test at the Institute for Transformative Technologies (ITT) in India. ITT is evaluating multiple energy storage systems as part of its rural electrification program. Currently, remote locations generate power through diesel generators, which are costly to operate and produce air pollution and greenhouse gasses. Officials are hoping to replace those dinosaurs with mini-grids made of solar arrays and energy storage systems such as the UltraFlex.

The cost of solar and wind power is approaching grid parity, even without subsidies, but energy storage is needed to balance supply and demand. Electric vehicles have a lower total cost of ownership than internal combustion engine vehicles, but their high initial price tag and somewhat limited range puts EVs at a disadvantage. Engineers are working to build a better battery and solve both of those problems. The noble quest for the Holy Grail continues.

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