At the CES show in Las Vegas this week, Hyundai rolled out its latest hydrogen fuel-cell vehicle, a crossover shaped car called Nexo that will replace the hydrogen powered ix35 that went on (limited) sale in 2013.
Unlike the ix35, the Nexo is apparently designed for hydrogen power from the ground up, which will have made it easier to squeeze in all the bit and pieces required by a fuel cell car. Most problematic tend to be the bulky storage tanks for holding hydrogen gas at pressures of up to 700 bar.
If 700 bar feels hard to imagine, note that it’s the same pressure felt by a submarine submerged seven kilometres below the surface of the ocean, or most of the way to the bottom of the Atlantic. The tanks aren’t exactly party balloons, in other words, and need to be fiercely strong and sturdy as a result.
While the hydrogen ix35 featured two tanks of differing size – a big one in the boot and a small one under the rear seats – the Nexo has three equal size cylinders installed in a row under the rear seats and boot floor. Each tank holds 52 litres and altogether they can swallow a total of 6.3kg of hydrogen, compared to 5.6kg for a fully topped up ix35.
As well as carrying more hydrogen the Nexo is also more efficient than its predecessor, managing about 59 miles per kilo of hydrogen versus 47 miles per kilo for the ix35 (under the reasonably realistic US testing regime). Hyundai seems pretty pleased with this progress and says the Nexo fuel cell system now achieves 60% efficiency. Range between fill-ups has increased from 265 miles to 370 miles for the ix35 and Nexo respectively (again under the US assessment – European figures put the Nexo at 500 miles).
A fuel cell generates electricity directly from hydrogen, and the Nexo is propelled by a front-mounted electric motor rated at 120kW (161bhp), a step up from 100kW (134bhp) of the ix35. An accompanying 30% boost in torque helps the Nexo reach 60mph in just 9.5 seconds.
A battery at the rear of the car allows the Nexo to recapture and store energy, in much the same manner as the battery in a petrol-electric hybrid like Toyota’s Prius.
Refuelling takes a maximum of five minutes, though filling stations capable of delivering hydrogen at 700 bar remain rare – only half a dozen are operational in the UK according to charging point specialists Zap-Map, out of 12 British hydrogen stations in total.
Accommodating bulky hydrogen tanks is one reason why Hyundai has stuck with an SUV shape for the Nexo, rather than follow Toyota’s example with the tall and ungainly Mirai saloon. To improve economy, the Nexo features flush, pop-out door handles, aero wheels, and a ducted “air curtain” around the rear pillar.
Inside, the company says it has made extensive use of “biomaterials” such as bamboo-derived textiles to achieve a 20% reduction in carbon emissions compared to its normal vehicles.