The United States develops a new type of electric vehicle battery, energy storage doubles -Lithium - Ion Battery Equipment
Envia could solve some key problems and cut the cost of electric vehicle batteries in half. Source: MIT Tech Startups
Envia, a startup with funding from General Motors (GM) and the U.S. government's Advanced Research Projects Agency for Energy (ARPA-E: Advanced Research Projects Agency for Energy), says it has made some batteries , can store more than twice as much energy as current electric vehicles. If the technology works, it could halve the cost of batteries, the most expensive component in electric vehicles.
However, much work remains to be done before batteries can be used in commercial electric vehicles. Among other advantages, they can certainly more than double the number of charge and discharge cycles.
The technology was highlighted at the annual Advanced Research Projects Agency Division of Energy summit, held this week in Washington, D.C., in part to showcase energy technology advances made by the Department of Energy, which oversees advanced research projects Department of Energy. The Energy Department has come under fire for guaranteeing loans to companies that later declared bankruptcy.(Lithium - Ion Battery Equipment)
Envia's technology is based on research that began at the U.S. Department of Energy's Argonne National Lab, which found a material with a new microstructure that could help improve the storage capacity of battery electrodes.
General Motors and battery maker LG Chem, which is using some aspects of Chevrolet Volt technology, may integrate other technology from Argonne National Laboratory into batteries for next-generation vehicles. Envia has improved the original technology of Argonne National Laboratory to obtain higher energy density.
Using the Argonne material as a starting point, the researchers systematically tested changes to the material design to increase practical operating voltages (a powerful approach to increasing energy density), while addressing known material issues: It's the component manganese that tends to leave the electrodes and dissolve in the battery's electrolyte, which reduces storage capacity over time. To achieve these goals, the researchers added trace elements to the material and developed coatings that prevent manganese from escaping.
The company then turned its attention to the opposite electrode, which is usually made of graphite. The researchers decided to use silicon, which can store more energy, but typically fewer recharges because it swells and cracks. Envia solved these problems by using silicon in a porous form, which is more tolerant of expansion and contraction, and by mixing silicon with various forms of carbon, including carbon fibers and graphite. Carbon is meant to provide a pathway for electrons to travel through the material, bridging the gaps created by cracks in silicon. The researchers also had to improve the electrolyte to prevent it from dissolving in batteries at high voltages.
To develop the material, Envia took the unusual approach of testing the new electrode material in a complete battery, with both electrodes and electrolyte. Typically, researchers test electrode materials in isolation to determine those underlying properties, such as high energy storage capacity. Sometimes, though, some materials look fine on their own, but aren't compatible with electrolytes or other electrodes. On the other hand, there are some materials that don't look great on their own, but might be a good match with an appropriate electrolyte. So Envia tested batches of 1,500 battery cells, each with a different combination of electrodes and electrolyte, to find the best combination. Envia manufactures the electrode and electrolyte materials manually. Wildcat Discovery Technologies (Wildcat Discovery Technologies), which belongs to the "MIT Technology Startup" TR50 most innovative companies, uses robotic systems to speed up similar processes.
After testing a small battery the size of a coin, Envia made a battery large enough to be used in electric vehicles. Each piece weighs one kilogram and can store 400 watt-hours. Commercial lithium-ion batteries store approximately 120 to 250 watt-hours per kilogram.
Low-energy batteries often have safety features that make them attractive for use in cars. Envia's president and chief technology officer, Sujeet Kumar, said the company's batteries have passed the nail-piercing test, a key test for battery safety.