To Build a Better BatteryDesign News
by: Kevin Clemens
US-based Cadenza Innovation has found a way to configure batteries into packs that promise better safety, have greater volumetric energy density, and cost less.
One of the companies that accepted the RANGE challenge was a then-new startup called Cadenza Innovation. The small US firm was made up of world-recognized battery experts and led by Dr. Christina Lampe-Onnerud. With a Ph.D. from Uppsala, Sweden in inorganic chemistry, a post-doc assignment at MIT, and recent experience as the head of battery-maker Boston Power, Dr. Lampe-Onnerud saw that RANGE provided her startup with an opportunity to define some of the basic requirements that future lithium ion battery systems would be expected to meet.
|Dr. Christina Lampe-Onnerud is the founder and CEO of Cadenza Innovation, a US-based company that is working with lithium ion battery manufacturers to improve safety, performance, and cost of their products. (Image source: Cadenza Innovation)|
“I felt committed to the space and saw this opportunity to bring forward a platform that could lead with cost and safety, but that had to have the core property of high performance,” Dr. Lampe-Onnerud explained to Design News. “I took the opportunity to define high-performance as high volumetric energy density—meaning more energy in a given space than what you commonly see. I also had the chance to help define the concept the industry now considers safety. We could set a standard globally where a product can fail but never harm. In the battery world, that means you can have a battery stop working, but it can’t kill you, or explode, or start a fire in normal operating circumstances,” Lampe-Onnerud told us.
A large amount of lithium ion battery research takes place on the electrochemistry level—creating and testing new electrode and electrolyte materials, often in tiny coin-sized cells. The problem is that the sometimes promising results from laboratory testing don’t always work when scaled up to usable battery configurations. “Everyone gets so excited for the tiniest electron shift, forgetting that it takes a lot of work to get from that into real product,” said Lampe-Onnerud. “And then, when you have real product, it’s still not a done deal. You have to qualify into the existing platforms.” Instead of working on basic battery cell chemistry, Cadenza set out to find ways to improve the packaging of the entire battery system.
Improving the System
The Cadenza team noted that a small system defect of fault could initiate a large and potentially dangerous release of energy. When thermal runaway occurred in one cell, it could quickly spread to others, resulting in a fire that involved the entire pack. The Cadenza solution is called a “supercell.” It consists of a structure that holds the battery cells in place, which also separates them using a thermally insulating and fireproof material. The battery cells can be prismatic, pouch, or the cylindrical “jelly-rolls” that Lampe-Onnerud prefers for high energy density and ease in manufacturing.
|Cadenza’s thermally isolating support housing can help prevent thermal runaway from spreading from cell to cell. It also has an added fire suppressant that is activated at elevated temperatures. (Image source: Cadenza Innovation)|
“Basically, (we use) very high temperature ceramic fibers, and they are mixed in with insulation materials and with fire retardants. The process is a little bit like the one used to make egg cartons, but with ceramic instead of cellulose fibers,” Lampe-Onnerud said. “They are pre-shaped and shipped to the factory, and you ship in the jelly rolls and the metal pieces and then you assemble, activate the cells, and off they go!”
The ceramic fibers act as a fireproof thermal insulator between the cells, so if one cell experiences thermal runaway, it is less likely to spread to adjacent cells. The material bonding the supercell fibers together is also mixed with a fire-retarding material that is released if the structure reaches a critical temperature. Packaging smaller battery cells into standardized blocks allows the electrical connections to each cell to be simpler and more robust and reliable. Temperature activated electrical cutoffs can also be used to isolate the supercell blocks from one another in the event of thermal incidents.
The adaptability of the supercell is an important feature. “The architecture itself is chemistry agnostic. So that means you can commit robotics to the assembly of the cells without fearing that there will be a better cathode in years down the road. In fact, you just place it into the platform when it is commercially viable, price-wise,” said Lampe-Onnerud.
“This platform is incredibly simple to assemble and make this invention into the real thing. You can basically source less than 50 components globally and assemble it locally. So when the world goes into nationalism and protectionism, we have a platform that allows for domestic manufacturing,” said Lampe-Onnerud.