Today, there are two main ways to store the energy needed to power an electric car down the road: a large electrochemical battery pack which turns stored chemical energy into electrical power; or a hydrogen fuel cell system in which compressed hydrogen is combined with oxygen from the outside air inside a special fuel cell stack to produce water, heat and electricity.
But as one European automaker by the name of nanoFlowcell will tell you, there’s a third way that combines the best of liquid refueling and battery packs in something called a redox flow battery — or as it prefers to call them, a nanoflowcell battery. And while the company itself is just four years old, the company has just announced that it will be demonstrating the latest in a line of prototype electric vehicles at this year’s Geneva Motor Show that it hopes will revolutionize the way we think about electric cars.
Like its predecessors, the all-new prototype boasts an impressive performance on paper, with a claimed 186 mph top speed and a 2.4-second 0-62 mph time, along with a claimed range in excess of 600 miles on the standard NEDC test cycle. Yet unlike all of the other high-powered electric sports cars and concepts we’ve seen over the years there’s something particularly unusual about the aptly named nanoFlowcell QUANT 48VOLT: it runs on 48-volts.
When dealing with power electronics on modern electric cars, higher voltage systems have been preferred to lower-voltage systems for several important reasons. Firstly, since power is a product of Voltage and Current (and higher current flow increases power loss due to the electrical resistance of the conductor it is passing through), automakers today prefer to use high voltage, low current systems. Secondly, since high current flow requires the use of physically larger connectors and wires (to overcome any losses caused by resistance), it’s more practical to make electric cars using high-voltage components than it is low-voltage ones as the cables for power are more easily routed, lighter, and less bulky. Thirdly, high-voltage systems put far less strain on the car’s battery pack and result in a much less of a voltage drop toward the empty end of the pack when compared to a low-voltage battery system. And while higher-voltage systems require better electrical insulation than lower-voltage systems, the overall benefits of a high-voltage power system in an electric car tend to outweigh the disadvantages.
The nanoFlowcell’s QUANT 48VOLT doesn’t have to worry about battery voltage drop in the same way that a traditional battery electric car does, since it produces electricity by passing two oppositely-charged electrolytic solutions either side of a special catalyst-rich membrane that enables ion exchange from one side to the other, producing electricity in the process. Since the system power output is restricted by the physical area of the flowcell membrane (and the electrolyte is pumped through the membrane from the ‘charged’ tank to the ’empty’ tank), power output from the cell remains constant regardless of how ‘full’ the tank is.
Unfortunately though, there are some downsides to flow cell technology. For example, traditionally, it’s been impossible to vary the voltage or power produced by a flow cell in response to demand from the electric motor. Instead, batteries or supercapacitors have been required to buffer power produced by the flow cell to ensure that power could be buffered to ensure both high and low demand situations be catered for. Additionally, flow cell systems have been unable to match the power density of modern lithium-ion battery chemistries, making them less appealing for use in power-hungry applications like electric cars.
Yet nanoFlowcell — which was founded in Liechtenstein (Europe’s fourth-smallest country) before moving its engineering division over the border to Switzerland and its business division to London — says it has solved both of those problems with its latest nanoflowcell technology, producing a flow cell stack made up of six flow cells in parallel that can produce the low voltage and high current required of them to power the QUANT 48VOLT’s quartet of 120 kilowatt electric motors. With variable power output, the company says the system is lighter and less complex than previous generation systems too, lowering overall cost.
As it’s a prototype, cost hasn’t been mentioned yet — but if we’re honest we don’t yet think we’ll see a nanoFlowcell car on the roads any time soon. As something of an unknown automaker, the various QUANT prototypes we’ve seen from nanoFlowcell (both in conjunction with its partnership with Swedish hypercar manufacturer Koenigsegg and on its own) have been impressive on paper but as yet have not resulted in a practical production model you can buy. And while flow cell technology does have its benefits over traditional electrochemical batteries (such as negligible degradation over time and quick refuelling time) it’s essentially marred by the same problems affecting hydrogen fuel cell vehicles: refuelling infrastructure and power density.
There’s no doubt that flow cell technology is another alternative to storing power for an electric car, but without significant support from automakers and fueling companies it’s unlikely to make an impact on the automotive world.
And unlike hydrogen — the majority of which is still produced through steam reforming of compressed natural gas — there’s less incentive for fossil fuel companies to embrace a technology they can’t have a hand in producing.
Do you think flow cell technology has a future? Is it going to replace traditional battery packs in electric cars? Or is it just too complicated and an unnecessary distraction when companies like Tesla, BMW, Audi and Daimler are working on technology that can recharge an electric car’s battery pack in as little as ten to fifteen minutes?
Leave your thoughts in the Comments below.
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