The 2007 Tucson-based prototype had a 100kW fuel cell, a 152-litre gas tank, a 93mph top speed and a 186-mile range. Today’s car, based on the ix35 SUV has a 100kW fuel cell equivalent to 134bhp, a 144 litre of hydrogen capacity in two tanks, a 100mph top speed and a range of 369 miles.
Getting under the ix35 Fuel Cell’s skin
From the inside and outside - aside from a slightly smaller boot - the ix35 is completely conventional, down to the standard-issue autobox shift lever. Under the skin, however, it is completely new.
The fuel, compressed hydrogen at a pressure of 700 bar, is housed in two gas cylinders in place of a conventional petrol tank – a smaller 40-litre unit in front of the rear axle and a 104-litre tank behind the rear axle.
A fuel cell is mounted under the bonnet. The hybrid battery packs are located under the vehicle, positioned in the centre for weight distribution. Inside the fuel cell, an anode and cathode sandwich, and a polymer electrolyte membrane.
When the hydrogen flows over the anode, it splits into hydrogen protons and electrons. The polymer electrolyte membrane only allows the protons to pass through. The electrons travel to an external circuit which operates the motor. At the cathode, electrons and protons react with oxygen from the air to create water as a by-product of the process. Hyundai claims the driving range is 369 miles on a tank of gas.
The compact SUV uses 0.95kg of hydrogen to cover 62 miles and has a maximum tank capacity of 5.64kg of gas. The front wheels are driven by a 65kW - equivalent to 87.2bhp - electric motor, through a single speed reducer gear.
Under the floor is a 24kW battery developed by LG Chemicals, which is used primarily to assist the fuel cell stack when power demand is at its greatest. The battery pack is also used to ‘harvest’ waste energy from the regenerative braking system.
Behind the ix35 Fuel Cell’s wheel
The biggest compliments that can be paid to the Hyundai ix35 Fuel Cell is that it looks very much like a regular ix35 from the outside and drives like any other electrically powered vehicle. There are a few subtle differences.
Up at the front is a grille that's bespoke on the Fuel Cell variant of the ix35. The grille is functional and there are two cooling radiators behind it, one to cool the stack, the other is for the traditional systems such as air conditioning and so on.
A blue-tinged Hyundai emblem provides another hint that this is no ordinary ix35. On the instrumentation panel, the dial on the left indicates ‘charge’ and ‘power’ to show when you’re expending the available electricity and when you’re recouping it through regenerative braking.
The right-hand dial shows your speed and remaining fuel level. There’s no noise on start-up, or thereafter, and step off from a standstill is impressively brisk, with 221lb ft of torque instantly on tap. Not that the performance is barnstorming; at more that 100kg heavier than a regular ix35, it is more than 1.5sec slower than a 2.0-litre diesel to 62mph, and maxes out at about 100mph.
Still, it feels perfectly comfortable to drive in the urban environment for which it is mainly intended. In contrast, the Nissan Leaf - arguably the best of the plug-in bunch - will manage just 130 miles before its battery is exhausted.