Envia's 45 amp-hour lithium-ion battery cells

Envia Systems battery breakthrough for affordable 300 mile range electric cars

Envia Systems is due to announce a dramatically improved lithium-ion battery design, with over twice the energy density and 1/4th the cost of current lithium-ion batteries, at the ARPA-E conference this week. Could lead to the long range affordable electric car of our dreams?

Lithium battery startup company Envia Systems plans to announce tomorrow, at the ARPA-E conference, development of a high energy density lithium battery (400 watt-hours per kilogram) which could be the tipping point enabling long range affordable electric cars. Long range electric cars have been possible for quite awhile, Solectria built one in the 1990's, and Tesla Motors has been selling the Roadster and will soon be selling the Model S with battery packs sufficient for 200-300 miles of all electric driving range. What Envia brings to this is higher energy density and lower cost, a combination which would make for an affordable, long range, electric car with a 300-mile range and a price around $25,000 to $30,000.

The company is a Silicon Valley startup founded in 2007, headquartered in Newark CA, and with a prototyping and manufacturing plant in Jiaxing China. The company received a $4 million ARPA-E award in the High Energy Density Lithium Batteries program, as well as significant amounts of private investment from GM Ventures and others.

Envia's technology is a new cathode design for lithium-Ion batteries which the company calls the High Capacity Manganese Rich (HCMR) cathode. It's claimed the design has excellent stability, long lifetime in charge cycles, and a high per cell voltage. The company has also designed anode and electrolyte materials required to build complete batteries. Batteries have a positive terminal (the anode), a negative terminal (the cathode), and an electrolyte mix between the two. Electrons move between the anode and cathode through the electrolyte.

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Comments

The energy density number from an automotive perspective depends on power, usable energy, cycle life and calendar life in large format cells. The 400Wh/kg for Envia’s cells represents a 2.5x improvement over an automotive grade cell. While it is impressive to hear higher energy density numbers, it has to be related to cost and performance in automotive. Envia has built 45Ah cells that have cycled greater than 400 cycles at 80% DoD. We are going through qualification cycles with automotive OEMs around the world.
What is the power density (W/kg)?
I think you dropped a decimal point: "capacity of 46 amp-hours and an energy density of 400 watt-hours/Kilogram. By comparison the NCR18650A manufactured by Panasonic has 3.1 amp-hours capacity, " That would be 4.6. And Panasonic's current batteries for Tesla are 3.8, with 4.6 in development, or SLT.

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