Automotive Engineer

There is consensus in the industry that there isn’t one single solution to replacing the internal combustion engine as the main power source in vehicles. Over the past 100 years, burning liquid fuel has allowed people to expand cities, grow businesses and made travelling between far-flung locations possible. But reliance on fossil fuels isn’t sustainable, and more pressingly the need to reduce vehicle tailpipe emissions is growing.

OEMs such as Nissan and Renault have invested heavily in battery technology and pure electric vehicles. But at present the technology can’t offer the same range as a tank of fuel, so electric vehicles are limited to urban applications.

Opel-Vauxhall has developed its range-extended Ampera to fill the void between the freedom a combustion engine gives – it has a range of 500km – and the emissions reduction a battery-electric vehicle offers. Official figures show the Ampera emits just 40g/km CO2.

The C-segment Ampera has spent most of its development cycle in the US as part of the Chevrolet Volt project, but European engineers had a large part to play too. Dr Lars Peter Thiesen, Opel’s manager of alternative propulsion, says: “There was very intensive work conducted by both Germany and the US, particularly on the main component in the car, the battery. We had engineers working in Opel’s alternative propulsion centre in Mainz-Kastel, near Rüsselsheim, testing the batteries through various driving cycles in conjunction with colleagues in GM’s battery assembly facilities in Brownstown Township near Detroit.”

The batteries – which use cells supplied by LG Chem – were also subjected to tests in climate chambers and rattle tests on both sides of the Atlantic, according to Thiesen. Real-world testing was conducted in the 47°C heat of Death Valley, Nevada and in the extreme cold of Kapuskasing, Ontario, Canada, where temperatures can plummet to as low as -36°C. 

The result of all this work is that the Ampera’s 16kWh lithium-manganese spinel battery gives an electric-only range of up to 80km. It isn’t easy to reach that level during normal driving. Around the streets of the Hague in the Netherlands, I managed to achieve the official range before the gasoline range-extender engine switched on, but I rarely drove above 88km/h which caused a long line of traffic behind me. But however quickly or slowly you deplete the energy in the battery it will help improve the Ampera’s overall efficiency – which was the defining point of the project.