Simplify the production of lithium-ion batteries | MIT News



When it comes to battery innovations, a lot of attention is paid to potential new chemistries and materials. We often forget the importance of production processes to reduce costs.

Now, MIT spin-out 24M Technologies has simplified lithium-ion battery production with a new design that requires fewer materials and fewer steps to make each cell. The company says the design, which it calls “SemiSolid” for its use of sticky electrodes, cuts production costs by up to 40%. The approach also improves the energy density, safety and recyclability of batteries.

Judging by industry interest, 24M is onto something. Since coming out of stealth mode in 2015, 24M has licensed its technology to multinational companies such as Volkswagen, Fujifilm, Lucas TVS, Axxiva and Freyr. The latter three companies plan to build gigafactories (factories with annual gigawatt-scale production capacity) based on 24M technology in India, China, Norway and the United States.

“The SemiSolid platform is proven to scale hundreds of megawatts produced for residential energy storage systems. Now we want to prove it at gigawatt scale,” says 24M CEO Naoki Ota, whose team includes 24M co-founder, chief scientist and MIT professor Yet-Ming Chiang.

Establishing large-scale production lines is only the first phase of 24M’s plan. Another key part of its battery design is that it can work with different combinations of lithium-ion chemistries. This means that 24M partners can incorporate higher performance materials across the line without significantly changing manufacturing processes.

The kind of rapid, large-scale production of next-generation batteries that 24M hopes to enable could have a huge impact on battery adoption in society, from the cost and performance of electric cars to the ability of renewables to replace fossil fuels.

“It’s a platform technology,” says Ota. “We are not only a low-cost and highly reliable operator. That’s who we are today, but we can also compete with next-generation chemistry. We can use any chemistry on the market without our customers changing their supply chains. Other startups are trying to solve this problem tomorrow, not today. Our technology can solve the problem today and tomorrow.

A simplified design

Chiang, who is the Kyocera Professor of Materials Science and Engineering at MIT, got his first taste of large-scale battery production after co-founding another battery company, A123 Systems, in 2001. As that company prepared to go public in the late 2000s, Chiang began to wonder if he could design a battery that would be easier to manufacture.

“I got this window into what drum making was like, and what struck me was that even though we were successful, it was an incredibly complicated manufacturing process,” says Chiang. “It is derived from magnetic tape manufacturing which was adapted to drums in the late 1980s.”

In his lab at MIT, where he has been a professor since 1985, Chiang started from scratch with a new type of device he called a “semi-solid flow battery” that pumps liquids carrying particle-based electrodes. to and from tanks to store a load. .

In 2010, Chiang partnered with W. Craig Carter, who is a POSCO Professor of Materials Science and Engineering at MIT, and the two professors supervised a student, Mihai Duduta ’11, who explored flow batteries for his undergraduate thesis. Within a month, Duduta had developed a prototype in Chiang’s lab, and 24M was born. (Duduta was the company’s first hire.)

But even as 24M worked with MIT’s Technology Licensing Office (TLO) to commercialize research done in Chiang’s lab, members of the company, including Duduta, began to rethink the flow battery concept. An internal cost analysis by Carter, who consulted 24M for several years, eventually led the researchers to change direction.

This left the company with loads of gooey slime that made up the electrodes of their flow batteries. A few weeks after Carter’s cost analysis, Duduta, then a principal investigator at 24M, decided to start using slurry to assemble the batteries by hand, mixing the sticky electrodes directly into the electrolyte. The idea caught on.

The main components of batteries are the positively and negatively charged electrodes and the electrolytic material that allows ions to flow between them. Traditional lithium-ion batteries use solid electrodes separated from the electrolyte by layers of plastics and inert metals, which hold the electrodes in place.

Eliminating the inert materials of traditional batteries and adopting the sticky electrode mix gives the 24M design a number of advantages.

For one thing, it eliminates the energy-intensive process of electrode drying and solidification in traditional lithium-ion production. The company says it also reduces the need for more than 80% of inactive materials in traditional batteries, including more expensive ones like copper and aluminum. The design also requires no binder and features extra thick electrodes, improving the energy density of the batteries.

“When you’re starting a business, the smart thing to do is to review all of your assumptions and ask yourself what’s the best way to achieve your goals, which in our case were low-cost, simply-made batteries,” says Chiang. “We decided that our real value was in making a lithium-ion slurry that was electrochemically active all along, with electrolyte in it, and you just use the electrolyte as a processing solvent.”

In 2017, 24M participated in MIT’s Industrial Linkage Program STEX25 Startup Accelerator, in which Chiang and his collaborators forged critical industry connections that would help him secure early partnerships. 24M has also collaborated with MIT researchers on projects funded by the Department of Energy.

Enable Battery Revolution

Most of 24M’s partners are eyeing the rapidly growing electric vehicle (EV) market for their batteries, and the founders believe their technology will accelerate EV adoption. (Battery costs are 30-40% of the price of electric vehicles, according to the Institute for Energy Research).

“Lithium-ion batteries have made huge improvements over the years, but even Elon Musk says we need breakthrough technology,” Ota says, referring to the CEO of electric vehicle company Tesla. “To make EVs more mainstream, we need a breakthrough in production costs; we can’t just rely on cost reduction through scaling up, because we’re already making a lot of batteries today.” today.”

24M is also working to prove new battery chemistries that its partners could quickly integrate into their gigafactories. In January of this year, 24M received a grant from the Department of Energy’s ARPA-E program to develop and scale a high-energy-density battery that uses a lithium metal anode and a semi-solid cathode. solid for use in electric aviation.

This project is one of many around the world designed to validate new lithium-ion battery chemistries that could enable a long-sought battery revolution. As 24M continues to drive the creation of large-scale, global production lines, the team believes it is well positioned to turn lab innovations into ubiquitous, game-changing products.

“This technology is a platform, and our vision is to be like Google’s Android [operating system], where other people can create things on our platform,” says Ota. “We want to do that, but with hardware. That’s why we license the technology. Our partners can use the same production lines to benefit from the advantages of new chemistries and approaches. This platform gives everyone more options.

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