March 1st, 2012 by Envia Systems Inc
Envia Systems, a technology leader in high-performance, low-cost lithium-ion energy storage solutions announced on 27 February 2012 test results that verify the company’s next-generation rechargeable battery has achieved the highest recorded energy density of 400 Watt-hours/kilogram (Wh/kg) for a rechargeable lithium-ion cell, which is over two times the energy density of what was previously possible for rechargeable lithium-ion batteries.
The new battery is also considerably cheaper to manufacture because of less expensive materials. The new battery combines a High Capacity Manganese Rich (HCMR) cathode with a silicon-carbon nanocomposite anode. The electrolyte through which the lithium ions pass has also been altered to allow for a higher voltage.
When commercialized, this 400 Wh / kg battery is expected to slash the price of a 300-mile range electric vehicle by cutting the cost of the battery pack by more than 50 percent.
The testing of Envia’s next-generation lithium-ion battery was performed by the Electrochemical Power Systems Department at the Naval Surface Warfare Center (NSWC) in Crane, Indiana, under the sponsorship of Advanced Research Projects Agency – Energy (ARPA-E).
Tests at various cycling rates at NSWC confirmed that Envia’s automotive battery cell demonstrated energy density between 378-418 Wh/kg for rates between C/3 to C/10 for a 45 Amp-hour (C/3) cell. (C rating is the ratio of time taken for the full discharge of a battery in 1 hour versus a factor of 1 hour. For example, C/10 refers to discharging the battery in 10 hrs. C/3 refers to discharging the battery in 3 hrs.)
Similar cells have been cycling in Envia’s test labs for over 300 cycles. NSWC Crane will also test these cells to validate cycling performance.
“Since the inception of Envia, our product team has worked tirelessly and logged over 25 million test channel hours to optimally develop each of the active components of the battery: Envia’s proprietary Si-C anode, HCMR cathode and EHV electrolyte,” said Dr. Sujeet Kumar, Envia Systems co-founder, president & CTO.
“Rather than just a proof-of-concept of energy density, I am pleased that our team was successful in actually delivering 400 Wh/kg automotive grade 45 Ah lithium-ion rechargeable cells.”
“Envia’s new battery technology represents exactly the kind of innovation and breakthroughs that ARPA-E is looking for from the American research and development community,” said ARPA-E Director Arun Majumdar. “We hope that this low cost and high density battery technology enables wide spread adoption of electric vehicles across the country and around the world.”
“In an industry where energy density tends to increase 5% a year, our achievement of more than doubling state-of-art energy density and lowering cost by half is a giant step towards realizing Envia’s mission of mass market affordability of a 300-mile electric vehicle,” said Envia Systems Chairman and CEO Atul Kapadia.
Envia System’s patented cathode, anode and electrolyte materials enables its batteries to deliver high energy density, safety, and calendar life.
Envia Systems, in partnership with Argonne National Laboratory, received $4 million from the Advanced Research Projects Agency-Energy (ARPA-E), and a $1 million grant from the California Energy Commission in 2010 to develop high energy density batteries for electric vehicles.