The push for this service has been swift and strong: As the new scale-up facility is being constructed, Argonne has already brought two interim labs online -- one for cathode materials and one for electrolyte materials. The battery electrolyte setup is for research to "improve safety, lower flammability limits [and] prevent thermal runaways," according to Krumdick. "Cathode material is where you improve your energy density, improve your performance, improve your cycle life of your battery."
In an expansive warehouse-like building on Argonne's campus, over the din of compressors and fans, scientists working under fume and powder hoods mix solutions in glass co-precipitation reactors. The resulting blue-green liquid sits in large 20-liter containers, with brown cathode materials settling at the bottom. This material is washed, dried, mixed with lithium salts and heated.
Leaping from the bench to the Volt
The final black powder, weighing about a kilogram per batch, is placed into silver pouches to be made into test batteries, usually the standard 18650 cells, which are about the size of AA batteries, or pouch cells, like those used in mobile phones. "This size is what industry could really test and make substantial numbers of cells to determine 'Is this material good?'" said Krumdick. The material is also compared to the substances produced in small batches to make sure it still behaves the same way.
The interim electrolyte facility, which has been running for over a year, uses conventional equipment for mixing and processing organic substances. Researchers have already scaled up six electrolyte compounds. They began transferring equipment to the new scale-up facility last week, though parts of the site are still under construction. With the improved safety systems in the new lab, Krumdick expects to increase production throughput further with a 200-liter reactor.
The cathode facility proved more challenging. "Being able to make and scale up a cathode material is not a trivial task, and the equipment needed is not readily available," Krumdick said, noting that the hardware, like calcining furnaces with precise atmospheric controls, had to be purchased from South Korea, Japan and Germany.
The temporary lab has been operational for six months, and the team is still ironing out the process. "We've made material, but we don't feel it's been fully optimized, and we're still working on improving its properties," he said. Eventually, Krumdick anticipates making 100-kilogram batches of cathode compounds.
This quantity is an important threshold. "You could easily take it up to the ton quantity and your economic calculations would be linear, so you would be able to calculate out just what it would cost to make that material," said Krumdick. The lab is now negotiating licensing agreements for its materials with several companies. A cathode material developed at Argonne is already used in the 2011 Chevrolet Volt, General Motors Co.'s plug-in hybrid electric car.
With new materials, researchers can also build batteries for testing. At the Electrochemical Analysis and Diagnostics Laboratory, researchers put devices -- individual cells and full-size multicell modules, ranging from tall metal cylinders to flat boxes -- through tests that simulate a lifetime of use to see how things fail and how performance degrades.
The O'Hare/Palm Springs tests
Behind glass doors in beige cabinets, batteries are charged and discharged repeatedly under a spectrum of ordinary, not extraordinary, temperature and atmospheric conditions, to see how the batteries would respond if they were left in the long-term parking lot at Chicago's O'Hare Airport in the winter or if they would still function after a hot week in Palm Springs, Calif. The computer-controlled testing system runs 24 hours a day.