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Here at GreenCarReports, we’re fans of all-electric cars, but even we have to admit that most electric cars on the market today suffer from the same problem: limited range.
But according to battery firm Envia Systems, the days of limited-range electric cars could soon be over, thanks to a new battery which almost triples the energy density of current electric car battery technology.
Better still, Envia claims its new battery technology is more than 50 percent cheaper than current generation electric car batteries, costing around $125 per kilowatt-hour.
Envia’s lithium-ion batteries use a Silicon Carbon Carbide (Si-C) nanocomposite anode, High Capacity Manganese Rich (HCMR) nanocoated cathode, and patented Envia High Voltage (EHV) electrolyte, which enables them to achieve an energy density of 400 watt-hours per kilogram.
That’s all very well, but what does it mean in real-world terms?
To help make a comparison, the current lithium-manganese battery pack the 2011/12 Nissan Leaf has an energy density of 140 watt-hours per kilogram, while the recently-retired Tesla Roadster has a battery pack energy density of around 130 watt-hours per kilogram. Envia's battery technology is more than triple that.
Put another way, if the current battery pack in a 2011/12 Nissan Leaf was replaced with a pack made of Envia cells -- and we assume that the weight of all the non-battery cell components of the pack remain the same weight -- it would store almost 61 kilowatt-hours of energy.
Using the EPA’s combined rating for the Nissan Leaf as a guide, that equates to a theoretical range of around 170 miles per charge.

Envia Battery Technology
“In an industry where energy density tends to increases 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 elerctric vehicle,” said Envia Systems Chairman and CEO Atul Kapadia.
That’s a breakthrough that hasn’t gone un-noticed, even if the battery technology might still be a few years from implementation in a production electric car.
In fact, Envia’s new battery technology has earned it a $7 million strategic investment from General Motor’s venture capital arm, along with a further $10 million from other interested firms during the same 2011 equity investment round.
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400WH/KG: spectacular breakthrough again, except per Envia's website that drops like a rock after a few charging cycles and flattens out at half that capacity after about 450 cyles, or less than 2 years of use in an EV. Still some work to be done it appears.
I look forward to more updates from them, but won't hold my breath.
Anyway it's a good break through. I'm happy to see any break through. I going to think of this more like a 300 Wh/Kg cell though than a 400 Wh/kg one.
Envia acknowledges more work needs to be done to improve cycle life. Demonstrating cycling and energy density in a 45Ah cell as opposed to coin cells and extrapolating shows the technology is real. The important thing is to first reach the energy density and then continue to improve cycle life.
To put the current cell level achievement in terms of vehicle performance - each charge/discharge cycle represents 300 miles (since at this 45Ah cell footprint and $125/kWh cell cost a 300-mile pack should be affordable). So 450 cycles represents 135,000 miles.
Hope that helps.
Please note the capacity fade by cycling at 80% DoD for >400 cycles is from 35Ah to 26Ah about 25% (not 45Ah to 26Ah). As explained earlier on this thread, 45Ah is at 100%DoD.
So the effective range after >400 cycles in this example at 135,000 miles would be about 225 miles. All EVs have similar capacity fade/range reduction through their accumulated Watt hours of cycling.
The 400Wh/kg at $125/kWh (cell level) breakthrough should enable an affordable 300-mile EV. Current state-of-the-art in automotive is $250-$350/kWh (cell level). This price point and energy density enables a larger pack and fundamentally solves the "range anxiety" problem affordably. In response to Chris O, we acknowledged we need to improve cycle life. But we put our achievement in perspective at a vehicle level - 135,000 miles (not 50,000 miles).
batteries cost nowadays. Ditto for DBM-Energy in Germany. That's where I would place my bets. Sorry to say that the slippery surface technology developed by MIT and licensed to A123 Systems,
is not going well - the surface clogs up over time. Beware statements from companies searching for investors.
Please note that the $125/kWh cost for Envia is at a cell-level. We would like to be precise on the distinction between cell and pack. Our website shows a comparison of current state-of-the-art cost at a cell level and it is in the range of $250-$350/kWh versus Envia's $125/kWh.
We have been one of the most cash-efficient battery start-ups out there. Over the past 4.5 years, we have raised $28M and have most of our publicly announced Series C (December 2010) funds still in our bank. Envia is not raising any capital. This announcement is a reflection of our enthusiasm that an affordable 300-mile electric car will be real in our foreseeable future.
Very good question. The breakthrough on the cathode came first. Envia's cathode achieves 275mAh/g discharge capacity compared to ~150mAh/g (or less) for layered and olivine chemistries. Please visit our website for technical details of our cathode.
If you build it we will buy it.
I don't mind lower-capacity cells at a lower price. But when density goes up - so does risk.
Higher specific energy densities actually enable thinner cells for a given cell rated capacity. This would help in easier heat dissipation regardless of whatever cooling strategy is used (i.e. liquid or air-cooled). Envia's cathode has very good DSC (differential scanning calorimetry) performance. Please visit our website (www.enviasystems.com) for technical details.
We are currently going through qualification cycles with automotive OEMs around the world. The qualification tests include nail penetration tests in large format cells.
GM spent a billion dollars over the 1990 decade developing the EV1 project just to show America wasn't ready for electric cars. They pulled the EV1 plug claiming there was no demand despite the fact that every dealer that offered the EV1 had a waiting list & no owner wanted to give their EV1 back at lease end.
GM sucks & Volts are for dolts.
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