The Advanced Automotive Battery Conference saw Daniel Andree, a battery development engineer at Audi, take centre stage as he outlined how a Sanyo lithium-ion battery pack would be used in the upcoming 2012 Audi Q5 compact crossover hybrid.
The vehicle, which has an all-electric range of just under two miles, with a maximum all-electric speed of 62mph, has an electric drive mated to a 2.0litre turbocharged, direct injection four-cylinder petrol engine.
As for the battery pack itself, it is a 1.3kWh battery pack, weighs about 35kg and has a power density ratio of 1143W/kg. It supplies 40kW of a 180kW total powertrain output and its full pack performance ranges from between 30 per cent and 70 per cent SOC – a much wider window than with many other automakers.
It is cooled with cooling air volume and temperature controlled as needed. A lot of attention was focused on preventing turbulence within the air passages that could lead to uneven pressures and Audi also found that a battery pack air conditioning system could actually shorten the time to reach a specific cooling target.
Performance monitoring was also taken into account with the Q5’s battery management system storing historical stress data cell resistance and capacity as well as pack temperature and current distribution. According to Audi’s testing, in a worst-case scenario the battery pack’s capacity is reduced to about 60 per cent with cell resistance increasing by about 30 per cent by the end of the battery pack’s useful life.
The 2012 Audi Q5 Hybrid Quattro is scheduled to be released in Europe this spring and in North America later this year.
