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Interesting... see article below. Isn't the A123 battery density 33 wHr/lb (20,000wHr / 606lbs)? The battery tech below would suggest a much greater density of 180 wHr/kg (400 wHr/kg)! That would mean that, all else being equal, we could get up to 270 miles range using a 606lb Envia battery! Now, obviously one has to take into account operating ranges, power output, longevity/durability, volume density, etc etc., but on the face of it, pretty neat. Same weight of the current battery, but 5x more energy storage and thus, 5x more range than the current A123 battery!

Envia Systems announced today that a test sponsored by ARPA-E has verified the company’s impressive claims for its new battery cells. Envia’s prototype juice boxes have achieved an energy density of 400 Watt-hours/kilogram - the highest ever recorded for a rechargeable lithium-ion cell.

We’ll leave the hyperbole to the marketing folks, and settle for a couple of numerical comparisons. In an interview with, Envia CEO Atul Kapadia noted that current lithium-ion batteries deliver an energy density of around 100 to 150 Wh/kg. How does that translate into cost? The batteries used in the Nissan LEAF cost around $375 per kWh. Tesla CEO Elon Musk recently made an optimistic prediction that battery prices would drop below $200 per kWh in a few years. Once its new cells go into production, Envia expects costs to be as low as $125 per kWh.

The company plans to work with partners in the battery and auto fields, rather than doing its own manufacturing, and hopes to have its batteries in production vehicles in about three years. GM is a major investor in Envia, so the new supercells may show up in a future generation of the Volt.

Envia co-founder Dr. Sujeet Kumar explained some of the company’s proprietary technology. “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 lithium-ion rechargeable cells.”
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