Researchers at NASA are chasing a dream — advanced solid state batteries that can power electric planes. The Solid State Architecture Batteries for Enhanced Rechargeability and Safety (SABERS) program is centered at the agency’s Glenn Research Center in Cleveland, but is collaborating with researchers from Georgia Tech, Argonne National Laboratory and Pacific Northwest National Laboratory.
In a press releaseNASA says that, unlike conventional lithium-ion batteries, solid state batteries do not contain the liquids that over time can lead to overheating, fire and loss of charge – problems that may sound familiar to anyone using large electronics. In addition, solid state batteries can hold more energy and perform better in stressful environments than conventional lithium-ion batteries.
“SABERS continues to exceed its goals,” said Rocco Viggiano, SABERS principal investigator. “We are starting to approach this new frontier of battery research that could do so much more than lithium-ion batteries. The possibilities are pretty incredible.”
Battery performance is an important aspect in the development of more sustainable electric aircraft, whose batteries must be able to store the enormous amounts of energy needed to propel an aircraft while being as light as possible. However, the amount of energy a battery can store is only one side of the equation. In addition, a battery suitable for aviation purposes must be able to discharge its stored energy at a rate sufficient to power an electric aircraft or unmanned aerial vehicle.
NASA says a battery is like a bucket. Its capacity is how much the bucket can hold while its strength is how fast the bucket can be emptied. To power an electric plane, the battery must discharge its energy, or empty its bucket, at an extraordinarily high speed.
SABERS has experimented with innovative new materials not previously used in batteries, such as sulfur and selenium, which have made significant progress in power discharging. Over the past year, the team successfully increased their battery’s discharge rate by a factor of 10 and then by a factor of 5 again.
Those new materials led to additional design changes. The SABERS team realized that solid-state architecture allowed them to change the construction and packaging of their battery to save weight and increase the energy it can store. A bigger bucket, in other words.
Instead of housing each individual battery cell in its own steel housing like conventional lithium-ion batteries, all cells in the SABERS battery can be stacked vertically in one housing. Thanks in part to this new design, SABERS has shown that its solid-state batteries can have an energy density of 500 watt-hours per kilogram – double that of a traditional battery for electric cars. [It should be noted that Samsung say it also has a solid-state battery with a high energy density.]
“Not only does this design eliminate 30 to 40 percent of the battery’s weight, it also allows us to double or even triple the energy it can store, extending the capabilities of lithium-ion batteries considered to be the latest. far exceeds.” said Viggiano.
Safety is another important requirement for the use of batteries in electric aircraft. Unlike liquid batteries, solid-state batteries do not catch fire when defective and can still operate if damaged, making them attractive for aviation use.
SABERS researchers have tested their battery under various pressures and temperatures and found that it can operate at temperatures nearly twice as high as lithium-ion batteries without as much cooling technology. The team continues to test under even hotter conditions. Not surprisingly, this research has sparked significant interest from government, industry and academia.
This year, SABERS’ main goal has been to demonstrate that the properties of its solid-state battery meet its energy and safety targets, while demonstrating that it can operate safely under realistic conditions and at maximum power. Her research partners at Georgia Tech are helping to pioneer several methodologies that can improve solid-state batteries and make them more practical for use in aerospace applications.
“Georgia Tech has a big focus on micromechanics of how the cell changes during operation. That helped us look at the pressure in the battery, which allowed us to improve the battery even further,” said Viggiano. “It also led us to understand from a practical point of view how to manufacture a cell like this, and it led us to some other improved design configurations.”
SABERS has also brought in the expertise of multiple NASA centers and projects to achieve its objectives. In addition, his work has sparked the interest of the Subsonic Single Aft Engine program, which is working to develop an advanced hybrid-electric concept aircraft.
“We’ve had many productive discussions about how others at NASA can use our work and potentially use our battery,” Viggiano says. “It was extremely rewarding to think about what could possibly come out of it. We have seen SABERS grow from an idea we had lunch one day to possibly an energy solution for aviation.”
SABERS is part of the Convergent Aeronautics Solutions project, designed to give NASA researchers the tools they need to determine if their ideas to solve some of aviation’s biggest engineering challenges are feasible, and may be worthy of further pursuit within NASA or by industry.
The takeaway
To hear the reactionaries say: nothing the government does is good. The private sector is always better, smarter, faster, cheaper and more efficient. And yet research like that of the SABERS program often leads to breakthroughs that are later shared with private industry and become part of commercial products.
It’s easy to overlook the role that pure research activities like SABERS play in making discoveries that are too expensive or too massive for private industry, with its focus on the bottom line and the next quarterly report, to achieve alone .
While NASA’s work focuses on aircraft, the lessons learned will have huge implications for society as a whole. Imagine an electric car battery that has double the energy density of current batteries and weighs 40% less. How could that change the equation when it comes to driving the EV revolution forward?
Then consider that the NASA battery does not use cobalt, nickel or manganese – all components of most conventional lithium-ion batteries that are scarce and steadily increasing in price. America needs more basic scientific research. The SABERS program shows why.
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