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Yes, the world record energy density of 400Wh/kg in Li-ion rechargeable batteries has been achieved by Envia.
Project Manager: Dr. Herman Lopez, Director of Materials Development
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27 February 2012
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Envia Systems Prototype Cell Test
1. Introduction
GDD GXS 12-005
1.1 Naval Service Warfare Center, Crane Division (NSWC Crane) Test & Evaluation Branch was tasked by Advanced Research Products Agency - Energy (ARPA-E) to perform Verification & Validation testing on two high capacity lithium ion pouch type cells, manufactured by Envia Systems of Newark, California. The testing included verification of cell capacity and energy density at C/10 and C/3, 100% depth of discharge (DOD), as well as cell capacity and energy density at C/3, 80% DOD. One cycle at C/20 was performed at the manufacturer, therefore Crane's cycling started at cycle 2. Total testing cycles were 23, with 22 of those being performed at Crane (Cycles 2-23).
2. Test Samples
2.1 The Envia Systems cells are prototype lithium pouch rechargeable cells. The cells have a capacity of 46 Ah and an energy density of 400Wh/Kg. The cell's dimensions are approximately 97 mm wide, 190 mm long and 10 mm thick. The cell's approximate weight is 365 grams. Cell serial numbers are 400WhK-07-005-111205 (designated as 005) and 400WhK-07-006-111205 (designated as 006).
5. Conclusions
5.1 One of the highest energy cells used in consumer applications is the NCR18650A manufactured by Panasonic, which can be used as a comparative asset to the Envia cells. The NCR18650A cell specification claims 3100 mAh capacity, 3.6 V average and weighs 45.5 grams. The calculated energy density of this comparative cell would be approximately 245 Wh/Kg.
5.2 The test results from the prototype cells tested at Crane were in line with the results obtained from the manufacturer. The claims of 400 Wh/Kg were substantiated through the cycling tests performed at Crane. This is a 160% energy density increase over the industry standard indicated in paragraph 5.1. -
Here are some excerpts from Naval Surface
Warfare Center, Crane's test report. Full report available upon request.
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In an industry where energy density tends to increase five percent 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.
Atul Kapadia, Envia Systems Chairman & CEO
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. 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.
Dr. Sujeet Kumar, Envia Systems Co-Founder, President & CTO