There have been hydrogen cars before, but the Hyundai Nexo is perhaps the most convincing example to date, writes Chris Pickering
When asked to name the most technologically advanced car on sale, most people would probably hazard a guess at the current Mercedes S-Class (the latest in a long line of cars that has famously introduced such landmark innovations as ABS, active cruise control and crumple zones). But there’s another contender for that title, which comes not from Stuttgart or Silicon Valley, but from South Korea: the Hyundai Nexo.
The most obvious feature that sets the Nexo apart is the fact it runs on hydrogen. Located in its nose, the fuel-cell stack silently strips electrons away from the most abundant molecule in the universe, creating a steady flow of electric current. This is used to charge a 1.56kWh lithium-ion battery, which provides power to a 120kW electric motor, also mounted under the bonnet. The only tailpipe emissions are purified air (passed through the fuel cell’s sophisticated filtration system) and droplets of water vapour.
The Nexo is the second hydrogen car to come from Hyundai, following on from the ix35 Fuel Cell. At its heart is an all-new 95 kW fuel cell stack that’s said to offer 50 per cent better power density at 3.1kW/litre, while the overall powertrain efficiency now climbs to 60.4 per cent. Internal differences include a new design for the bipolar plates that separate out the individual cells, providing a more effective dispersion of air and hydrogen. Careful attention has also been applied to the humidity of the cells to ensure that they can function over a broad temperature range. Hyundai claims this has given the Nexo a class-leading cold-start capability, with the fuel cell capable of reaching working temperature in less than 30 seconds following an overnight soak at -29°C.
Notably, the Nexo has also been designed as a fuel-cell vehicle from the ground up, whereas ix35 was based on a combustion-engined platform. The new chassis uses a relatively conventional high-strength steel construction, but it has been carefully designed to suit the fuel-cell system’s packaging needs. In place of two tanks that took up a significant portion of the boot space in the ix35 there are now three carbon-fibre tanks – two of which sit under the rear seats. Not that you would guess from sitting in it, because the Nexo offers bags of rear-seat room and a generous 461-litre boot.
Things feel a little more radical from the front seats. The dashboard has been cleared entirely of buttons, which instead sit on a giant floating centre console. Meanwhile, the infotainment functions are handled by a vast touchscreen display, while another large screen behind the steering wheel provides a virtual instrument cluster. Combined, these features give the cabin a distinctly sci-fi appearance that’s more space station than SUV. It feels entirely in keeping with the Nexo’s cutting-edge character and its £65,995 price tag.
The materials are clever too. True, there’s the odd flimsy bit of plastic, but generally the quality is very good. All the major cabin surfaces, including the bamboo-based headliner, plastics, trim, soft skin and floor mats all come from UL-certified bio-materials. Hyundai says this represents the most extensive use of such materials on any vehicle to date.
Perhaps not surprisingly, the driving experience is much like a fully electric SUV. The Nexo feels quicker than its 9.5-second 0-to-60mph time would imply, with a steady stream of smooth, silent torque fed through a single-speed transmission. Unlike other fuel-cell cars we’ve driven you never hear the compressor at work either. Wind and road noise often become more noticeable in electric vehicles, but both are well suppressed here – aided in part by the Nexo’s impressively low drag co-efficient of 0.329 (down from 0.35 on the ix35).
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Further reading
- Fuel cell electric vehicles take autonomous 118-mile road trip
- Driving towards an energy dilemma: the inexorable rise of EVs
- Should businesses be revving up for an EV revolution?
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The feeling of serenity that comes from the Nexo’s powertrain refinement is bolstered by its soft, pillowy ride. There is a degree of body roll, but the handling feels reasonably precise, aided by the Nexo’s comparatively trim 1,825kg kerb weight (battery electric SUVs, in contrast, are often over two tonnes). This also helps to maximise the range, with 6.3kg of hydrogen (stored at 700 bar) good for a theoretical distance of 414 miles. That’s enough to take you from London to Leeds and back again.
Refuelling the Nexo only takes around five minutes and the process is barely more complicated than filling up a conventional car. Admittedly, the choice of filling stations is curently limited, with only around 20 in the UK (mostly around London and the Midlands) but that number looks set to grow.
So, it’s a thumbs up for the fuel cell, but that’s only half the story. The Nexo also has one of the most comprehensive suites of driving-assistance functions on the market. In addition to the usual autonomous emergency braking and lane keep assist there’s now a system that Hyundai dubs Blindspot View Monitoring (BVM). This uses a pair of wide-angle cameras mounted under the wing mirrors to capture a live video feed of the Nexo’s blindspots. As soon as you indicate left or right, the blindspot view from that side is automatically displayed in the instrument cluster. It sounds like something of a gimmick, but it works brilliantly, expanding your field of view while driving.
The Nexo also has a remote smart-parking function. This allows you to select a parking space then step out of the car, whereupon the Nexo will park itself automatically at the touch of a button. The practical application of this is that it allows you to guide the car into and out of very tight spaces, but it’s also a step towards fully autonomous parking. With Hyundai talking about offering SAE Level 4 autonomy in smart cities by 2021, it’s possible that future models may be able to drop you off in the city centre and find their own way to a car park.
The great thing about the Nexo, however, is that it still works here and now. It offers similar performance to its combustion-engined counterparts, with refinement levels that even a lot of electric vehicles would struggle to match. Crucially, it feels like a finished product, with enough practicality to use every day and sufficient quality to justify its aspirational price tag. The scarcity of hydrogen filling stations remains a challenge, but in some respects that’s a chicken-and-egg situation because there are so few fuel-cell vehicles currently on our roads. The Nexo, however, demonstrates that there is clear potential to tip that balance.
Hmm … fuel tanks under the seats containing hydrogen at 100’s bar pressure. I think some PPE may be in order:
https://youtu.be/3rAFMC2O9dQ
Looks very nice, I’d love one. However, it is well beyond what I’m prepared to spend on a car.
Obviously hydrogen is not easily available at present, so how much hydrogen is stored, and how? To supplement this storage, could one have cylinders at home (or in some safe store)?
The way to go! Five minute refuelling time! Lets spend the HS2 money on a hydrogen infrastructure instead.
Density of hydrogen at STP is 0.08988 g/L; so at 700 bar this is 56 g/L.
And thence so 6.3 kg occupies 112 litres.
I would guess that the container would weigh around 70kg but there is a lot of opportunity for lightweighting standard pressure vessels, so I am uncertain.
It would be interesting to know the the storage technology; if standard storage bottles were to be used then recharging might well be achieved by swapping bottles….
And what the cost breakdown is on this £65k price tag? And what is the opportunity to reduce the price and make it affordable??
Jack Broughton: to store a sensible amount of hydrogen gas it needs to be at high pressure; conventional gas cylinders being thick (= heavy) steel. BOC sell a “Hydrogen Manifolded Cylinder Pallet”: https://www.boconline.co.uk/shop/en/uk/gas-a-z/hydrogen-cylinders/high-purity-hydrogen-manifolded-cylinder-pallet which stores 108 cu.m. hydrogen = 9kg (or ~27kg / ~30L petrol equivalent based on calorific values) at a pressure of 175 bar. Weight is 1500 kg(!), a weight ratio of 167:1 for the fuel stored. Retail price £1062. You’d also need a gas booster to refuel @ 700 bar. All of which illustrate the major engineering challenges to produce a practical hydrogen fuelled car.
In fairness to Hyundai they’re maximising fuel efficiency by using fuel cells and carbon fibre for the pressure vessels offers good strength/weight.
I remain nervous about sitting directly over them, though – especially as they will be pressure cycling from 700 bar to “empty” hundreds or even thousands of times
200k to set up a fleet tank, nearest fill point is 60 miles from Bristol. Great idea but…
Trevor has made some good points about pressure cycling and interesting about weight of solid wall pressure vessels.
I suspect that pressure cycling would be reduce by having an “empty” state of, say 100 bar; but that does only slightly ameliorates the issue. And it should be noted that both carbon fibre and thermoset resins tend to be brittle ==> sudden failure. More sophisticated composites (thermoplastic & ultra high strength steel wires – for example) and/or cellular walls might be a cheaper and lightweight pressure vessel (and with a non-brittle failure mode to boot!).
Thanks for the analysis, Trevor, maybe I’ll defer my purchase even longer!
A few years ago there was a lot of talk about using metallic hydrides to store / provide hydrogen (avoiding the high pressure problem): has that idea bit the dust?
Sounds like a good design, but at £66,000.00 much too expensive for us mere mortals, plus until ITM Power are sponsored to build Hydrogen Filling Stations across the country and around Bristol, it’s going to stay a dream.
“The only tailpipe emissions are purified air and droplets of water vapour”. Maybe so. But what is the true cradle-to-grave environmental impact of this vehicle? Just because there are no nasty tailpipe emissions does not necessarily make this car a good thing. Once Joe and Joanna public cotton to just how environmentally damaging obtaining the materials for and then building PHEV and EV vehicles is, that will be the death knell for them, and hydrogen too if we are not careful
Can we have an reversible fuel cell, then it all could be used in the same way as a range extender bmw i3, but without the fossil fuel. An on board electrolyser would be almost as good. Still won’t solve congestion due to simply too many cars, but would surely reduce city pollution. No simple answers.
HS2 is a totally separate issue: if we build the right one, we will obviate the need for thousands of short haul flights per year, removing the need for new runway(s) at airports and carrying lots of people with green electricity as already done in Germany. That does not influence the fuel you put in your car and vice versa.
The vehicle must have passed the crash worthiness tests. I wonder how far away they were standing during the tests? I think the flames are colourless, so even more scary. This technology could go the same way as the zeppelins after the first burst pipe or filling station accident, but top marks for the courage of the investors.
HS2 only runs between a handful of destinations. Hardly flexible or useful, and it ignores the additional difficulties of getting to and from the access stations. And the passenger density and capacity means it will not have any significant impact on congestion.
It would appear from many of the comments that there is a lack of understanding.
1) Zeppelins. The H2 had burned off in the first few seconds. It was ignited deisel fuel on the clothes of passenger which caused great tragedy. Dont forget most cars have a fuel tank in the rear and also have electric cables to power the primary pump and quantity sensor
2) Carbon fibre bottles are often misunderstood. Have worked on high presure gas storage systems, the ‘bottle (s)’ are often a composite made up of a deep drawn metal liner swaged to form the neck surounded by a composite wave wound material made up from carbon fibre and other materials.
3) Duplex metal hydrides do have potential to store H2at less than 30 bar. Perhaps it is time to re examine the possibility – technology move on
4) The big problem with H2 is effective production. The large scale H2 plant in Germany uses natural gas as the source. What happens to the carbon rich residue?
I believe it is time to discuss and look at long term low environmetal impact solutions for the production of H2 a.
What a horribly misleading statement.
Hydrogen in the form of H2 is not abundant on Earth and needs to be made, typically from natural gas or other Carbon fuel.
Hydrogen should not be considered a “fuel” it’s more a storage medium like a battery since it has to be created rather than collected.
Car manufacturers are all making these >£50k “proof of concept” cars. Is anyone going to make a <£15k simple commuter car with some non-petrol component? This is what the average Joe on the street wants/needs not some executive toy to pretend they care about the environment.
No mention of the gross inefficiency and cost of hydrogen. Green Hydrogen comes from water electrolysis which is about 60% efficient, then it needs to be compressed, then it gets converted back to electricity in a fuel cell at about 60% efficiency. The compression needed uses about the same energy you get back from the Hydrogen. The result is worse than 30% energy storage.
The cost of hydrogen is more than taxed fuel, mainly because of the poor efficiency. This also means we would need to expand the electricity capacity 3x.
Batteries on the other hand are over 90% efficient and fuel is cheap with countries already wired.
Then we have the expense of Hydrogen filling station between $2m and $16m each.