Nano Flowcell Holdings hasn't been shy about promoting its flow-cell battery technology.
It's displayed flashy concept cars at multiple auto shows, offering bold performance claims for what it said were near production-ready designs.
But the company doesn't seem to have given outsiders any significant time behind the wheel of any of its prototype cars—until now.
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In a session at the TCS test track near Zurich, Switzerland, British car magazine Autocar was able to verify that Nano Flowcell's pair of prototypes are real, drivable cars, although that was about it.
Nano Flowcell has thus far built and shown two cars to demonstrate its technology: the Quant FE sedan and the smaller Quantino coupe.
Both are certified for testing on public roads in Germany, and are described as "beautifully built."
NanoFlowcell Quant F prototype
In place of conventional lithium-ion battery packs, flow-cell cars carry tanks filled with positive and negative liquid electrolytes.
They react inside the flow cell to produce electricity that powers electric motors to turn the wheels, just as in a battery-electric or hydrogen fuel-cell car.
The Quant FE features gullwing doors and one electric motor for each wheel. Nano Flowcell has said they produce a combined 1,075 horsepower.
ALSO SEE: New Quant Flow-Cell Car Concepts Arrive, Still Dodgy On Details (Mar 2015)
In the specification sampled by Autocar, the Quantino features a single electric motor powering the rear wheels, and a 48-volt electrical system.
It boasts 106 hp and 148 pound-feet of torque, enough for 0 to 62 mph in under 5.0 seconds, and a top speed of 124 mph, according to NanoFlowcell.
The company now says an unnamed "large manufacturer that is not German" has expressed interest in putting the Quantino into production.
NanoFlowcell Quantino concept
British testers found that the Quantino drove like small battery-electric cars, with instantly-available torque and noticeably strong regenerative braking.
The prototype borrows components like interior fittings from the BMW 2-Series, and has its flow cell mounted where the rear seats would be in a production model.
MORE: Quant F Electric Luxury Limo With Flow Cell Battery: Geneva Show Preview (Feb 2015)
Its pair of 159-liter (42-gallon) tanks provide a claimed range of over 600 miles, though it says the planned production model will have smaller 85-liter (22.4-gallon) tanks.
Flow-cell cars would require a network of filling stations to replenish their electrolyte tanks, but Nano Flowcell claims they would be a more convenient option than battery-electric cars.
Fueling station with twin-nozzle pump for bismuth-ion electrolyte solutions [NanoFlowcell]
It says flow-cell cars could be refilled with electrolyte in far less time than it takes to charge an electric car, and that infrastructure would be comparatively easier to develop.
However, so far it has not offered many details about how that could be accomplished.
Nonetheless, the company remains another example of the growing innovation around zero-emission vehicle technologies—whether or not it ultimately ends up in production.