Published: April 24, 2023 By

Photo: Solid Power's 22-layer, 20Ah all-solid-state lithium metal cell compared to the company's first-generation 10-layer, 2Ah cell. Courtesy of Solid Power.

In taking its technology from the lab to the streets, Solid Power is changing how electric vehicles run with less expensive, more efficient and safer battery technology.

Sehee Lee and Conrad StoldtA little over a decade ago, Conrad Stoldt and Se-Hee Lee, both associate professors of mechanical engineering at the time, answered a call to build a better battery. The appeal to double the energy density of a rechargeable battery came from the Defense Advanced Research Projects Agency (DARPA), a U.S. Department of Defense (DOD) office investing in ideas with the potential to offer “transformational change.” 

“The metrics they wanted to reach were unheard of,” said Stoldt, but he and Lee accepted the challenge anyway. “We saw it as an opportunity…and we sat down and determined that, at least on paper, the only rechargeable battery technology that could meet the specs for the program was a solid-state battery,” Stoldt said.

As their name suggests, solid-state batteries (SSBs) differ from conventional batteries in that the electrolyte powering them is a solid material instead of a gel or liquid. That gives SSBs many advantages over lithium-ion batteries now widely used in electronics, toys, appliances and—critically—electric vehicles (EVs).

At the time Lee and Stoldt turned their attention to it, work on SSBs in most parts of the world had largely been shelved for decades in lieu of liquid cell (lithium-ion) technology. They pulled it off that shelf and got to work on an entirely new breed of battery—one with the potential to revolutionize future mobile power markets while also positively impacting climate change.

When they received the 2007 DARPA grant, Lee had recently joined CU Boulder from the National Renewable Energy Lab (NREL), where he had worked on a ‘thin-film’ SSB (with limited energy-storing capacity) and wanted to explore what a larger-scale battery could look like. “I saw the advantage of the solid state, and I was always thinking, ‘How can we make this one really large battery?” he said.

What began as an idea “bootstrapped” in their own labs, said Stoldt, is now Louisville, Colorado-based Solid Power—an industry-leading developer of next-generation all-solid-state battery technology. Solid Power went public in 2021 (with many past CU Boulder students–undergraduate, Master’s and PhD—working within its ranks), major partnership deals with BMW and Ford, and a new 75,000-square-foot manufacturing facility in Thornton.

Solid Power’s innovative design bests lithium-ion cells on safety, cost, durability and battery life vectors long sought by consumers and automakers. Their technology swaps the flammable liquid in lithium-ion cells with a solid, sulfide-based electrolyte that is safer and more stable across a broad temperature range. Solid Power’s cells also easily outpace the conductivity and energy density of today’s best rechargeable batteries. The result is a smaller, lighter cell that is cheaper and gives a longer charge.

The slow burn of innovation

In 2011, Lee and Stoldt partnered with Douglas Campbell, a small business and early-stage product developer and current Solid Power chief technology officer, Joshua Buettner-Garrett, to start Solid Power. Along with Dave Jansen, then-mentor and now-interim CEO, president and chair of the company, the team negotiated a commercialization agreement with Venture Partners at CU Boulder (known then as the CU Technology Transfer Office), making the company an exclusive licensee to the university’s intellectual property.

The team was on its way to taking Solid Power from lab to marketplace with the intent to deploy the technology in a meaningful way in the ‘real’ world. “You could see over the horizon that it could be something more because we were pushing the boundaries of what energy storage could do, and there was literally nobody else in the U.S. doing it,” said Stoldt.

Next, Solid Power secured several million dollars in grant funding including federal grants, contracts and agreements, which included additional ARPA-E, Air Force and Department of Energy (DOE) grants, that kept them afloat during the slow burn of innovation that followed. Venture Partners and the Center for Translational Research now help startups through the steps to compete and win these types of grants.

“It was an endurance test from the start,” said Stoldt. But he credits the openness and talent surrounding them at CU Boulder with putting legs beneath the concept of an SSB that could do what the DOD and others wanted. “The freedom that the environment permits to pursue an idea and try to get it funded—that’s really how we started,” said Stoldt. “At the university, you have this critical expertise where you can walk down the hall to a colleague and say, ‘Hey, what do you think about this? Could we do this?’ It’s that talent and infrastructure and facilities that give the ability to pursue something like that. If I were trying to do this out of my garage, it wouldn’t have happened.”

In 2017, Solid Power first partnered with the BMW Group to jointly develop SSBs in high-performance electric vehicles. The next year, Solid Power closed its first round of equity-based financing with additional world-class investors. After the company launched its production line in Louisville, they entered a period of rapid innovation in which they were making, validating and delivering cells that far outperformed commercially available lithium-ion batteries. That impressed the BMW Group, the Ford Motor Company and Volta Technologies, which led a Series B investment round of $135 million in 2021.

That same year, the company opened its second production facility, increasing capacity to make the key material for SSBs. Their business model going forward is to only make and sell the solid electrolyte powder to battery makers who, by design, can incorporate the new material into their preexisting manufacturing facilities. It aims to make enough solid electrolyte annually to, by 2028, ‘fuel’ 800,000 EVs. In 2023, Solid Power and BMW expanded their joint agreement, allowing the automaker to manufacture SSB cells at its facilities, and BMW announced plans to begin testing vehicles with those new batteries this year. 

The double bottom line

Solid Power was founded on CU Boulder intellectual property and soon found that its university-created innovation had traction with corporate partners, which became their key investors. “It’s a really strong endorsement by the industry and validates desire for this technology,” said Bryn Rees, associate vice chancellor for Research & Innovation and managing director of Venture Partners at CU Boulder.

Solid Power's continued innovation was recognized with a recent $5.6 million DOE grant to continue developing its nickel- and cobalt-free cell. Amidst a global supply scramble to secure raw materials to meet demand for EV batteries, eliminating those high-priced materials would mean not only cost savings but fewer environmental, social and governance risks. When announcing the award, which is part of the Electric Vehicles for American Low-Carbon Living (EVs4ALL) program, U.S. Secretary of Energy Jennifer M. Granholm said, “This is a win-win for our efforts to fight climate change and power America’s clean transportation future with technologies produced by researchers and scientists right here at home.” 

Interim CEO Jansen agrees, and it reminds him of why he was a decade ago, and still is, excited about Solid Power—because it’s a major innovation with strong commercialization capacity and the potential to shift life as we know it. “It can change, and be transformative, to how things are done in the world,” he said. “These opportunities don’t come along all the time when really you can make a difference to the future of the planet.”