CAMBRIDGE, Massachusetts, June 24, 2015 (ENS) – An innovative approach to manufacturing lithium-ion batteries promises to halve the cost of the most widely used type of rechargeable batteries while boosting their performance and making them easier to recycle.
Developed by researchers at the Massachusetts Institute of Technology (MIT) and at a spinoff company called 24M, the new “semisolid” battery design is a hybrid between flow batteries and conventional solid ones.
Unlike conventional, solid lithium-ion batteries, the new semisolid cells are flexible enough to be bent and folded many times or even penetrated by bullets without affecting their performance, says co-inventor MIT’s Yet-Ming Chiang.
“We’ve reinvented the process,” says Dr. Chiang, the Kyocera Professor of Ceramics at MIT and a co-founder of 24M.
The current process for manufacturing lithium-ion batteries has changed little in the 20 years since the technology was invented. Chiang and co-inventor Dr. W. Craig Carter say the process is inefficient, with more steps and components than needed.
Their novel manufacturing process strips out the waste, speeds production and reduces the overall footprint to slash today’s lithium-ion battery costs by half.
The new process is based on a “flow battery” concept developed five years ago by Chiang and his colleagues.
In a flow battery, the electrodes are suspensions of tiny particles carried by a liquid and pumped through the battery’s compartments.
In the new version, while the electrode material does not flow, it is composed of a similar semisolid, colloidal suspension of particles.
This approach simplifies manufacturing, and makes batteries that are flexible and resistant to damage, says Chiang, who is senior author of a paper in the “Journal of Power Sources” describing the new process.
In addition to streamlining manufacturing enough to cut battery costs by half, Chiang says, the new system produces a battery that is more flexible and resilient. This should improve both safety and durability, he says.
The company has so far made about 10,000 batteries on its prototype assembly lines. They are undergoing testing by industrial partners, including an oil company in Thailand and Japanese heavy-equipment manufacturer IHI Corp.
The process has received eight patents and has 75 additional patents under review, while 24M has raised $50 million in financing from venture capital firms and a U.S. Department of Energy grant.
At first, the company is focusing on grid-scale installations, to help smooth out power loads and provide backup for renewable energy sources that produce intermittent output, such as wind and solar power.
But Chiang says the technology is also well suited to applications where weight and volume are limited, such as in electric vehicles.
PHOTO: A pilot manufacturing plant at 24M’s headquarters in Massachusetts has produced thousands of test batteries to demonstrate the efficiency of the new design. (Photo courtesy 24M)