PSA Peugeot Citroën recently demonstrated the H2Origin research vehicle based on a Peugeot Partner Origin cargo van. The project is a joint development in partnership with U.K.-based Intelligent Energy (IE), which provided the fuel-cell system, with partial funding from the U.K.’s Technology Strategy Board.
The three-year project produced the vehicle to demonstrate that a range-extending fuel-cell system can be packaged with an electric drivetrain beneath the bonnet of a compact vehicle. PSA already produces an electric variant of the Partner Origin, and the H2Origin was designed to extend the range of the electric model from 78 km (48 mi), measured on the New European Driving Cycle (NEDC), to 308 km (190 mi).
To this end, the H2Origin retains the electric drivetrain of the electric model, which is fitted with a Leroy-Somer SA 18-dc electric motor, producing peak power of 35 kW and maximum torque of 180 N·m (133 lb·ft). Supplying the energy is a 180-V Panasonic EV 95 95-A·h nickel metal-hydride battery pack rated at 15.4 kW·h and mounted beneath the load area floor in front of the rear axle.
Under the hood, the drive motor shares space with the Intelligent Energy fuel-cell stack, A2E/Soprano dc/dc converter, and their associated cooling systems, as well as a 12-V battery and relay box. The fuel-cell stack produces between 130 and 180 V and maximum current of 100 A while delivering a net output of 10 kW. To contain cost, IE’s stack design is of the PEM (proton exchange membrane) type.
IE claims that the stack can deliver full power within 2 min of startup, even at temperatures as low as -20°C (-4°F), because the stack includes its own heating system. A cooling system also is included to help ensure that the operating temperature remains in its optimal range up to 37°C (99°F). Cooling results from direct water injection; the water then partially evaporates to provide the necessary cooling. The system reduces a number of ancillary components, claims IE, thanks to the direct cooling and the humidifying effect, resulting from the water produced in the stack during the fuel-cell reaction. The steam in the fuel-cell exhaust is condensed in a heat exchanger to feed back into the fuel cell.
IE gives a maximum life of 5000 h for its mass-produced fuel cells, reckoned at around five years with use of 3 h/day. The system fitted to the H2Origin has a dry mass of 115 kg (254 lb).
PSA has chosen a high-pressure onboard storage system for the hydrogen needed to fuel the stack. The company is a participant in the StorHy joint venture between OEMs and technology partners designed to develop high-pressure storage systems for automotive applications. In the H2Origin, the gas is stored at 700 bar (10.2 ksi). According to PSA, this enables the H2Origin to carry 2.7 kg (6.0 lb) of gas compared with 1.6 kg (3.5 lb) at 350 bar (5070 psi).
The lightweight gas cylinders are sourced from Italian supplier Faber and are constructed using a stainless steel cylinder wrapped with carbon fiber and composite material. This established design has been used for storing compressed natural gas for more than 10 years.
PSA has opted for a swap rack system for the hydrogen cylinders, enabling the gas supply to be quickly replenished by switching a depleted gas supply with a recharged rack. The system features several safety systems to guard against leakage and fire. Each hydrogen cylinder is fitted with an excess flow valve, which will automatically cut off the gas supply if a large leak is detected. Similarly, a 700-bar pressure relief valve guards against a build up of pressure in the cylinder in case of fire.
Each rack will store 68 L of hydrogen at 700 bar in four cylinders. The gas storage system has a mass of 120 kg (265 lb) and is accommodated beneath a raised load floor in the vehicle.
In a power range between 6 and 10 kW, the stack operates at its greatest efficiency, approaching 50%. By supplying power to the drivetrain within this range, the fuel-cell stack ensures that the drain on the batteries is minimized.
“This is our second demonstration of a range-extender vehicle, and we are continuing to explore the potential," said Nicholas Lee, Head of Government and Technical Affairs for PSA Peugeot Citroën in London. "It looks promising in a small urban delivery vehicle, where there is potential for large reductions in both pollutants and noise.”
As the company points out, there are still problems to overcome, including cost, durability and reliability, size, and weight, although range-extending technology shows considerable promise.