Electric drive systems are still very much outsiders. The first vehicles of this type took to the roads around 1900, yet in 2009 no volume car manufacturer has a car powered exclusively by batteries in its lineup. Fewer than 1,500 electric vehicles are currently registered in Germany, corresponding to only 0.035 percent of all registered vehicles.
Yet electric driving potentially offers numerous advantages. Electric cars reduce the dependence of transportation and the economy on the raw material petroleum. They produce no direct exhaust emissions and thus ease the local burden on the environment. Electric drive systems are also significantly more efficient than combustion engines, consequently making them easier on the customers' wallets. Other strengths include sportiness and the fun they bring to driving. All of the torque is essentially available the moment the driver steps on the accelerator, allowing for breathtaking acceleration.
There is still a lot of work to do before electric cars are ready for volume production, however. The greatest challenge is the integration of the energy storage system. Acceptable range and performance requires a traction battery that is heavy and takes up a lot of space. Audi is taking a new approach to offset these disadvantages - a holistic approach with a specific vehicle package, a systematic lightweight construction concept and an optimal configuration of all components for the electric drive.
Audi e-tron - The Holistic Approach
The most important development related to batteries for electric drives are lithium-ion cells. Numerous experts throughout the world are working on their further development for use in cars, with the primary objectives being to reduce weight and increase capacity and performance. Audi has also opted for this technology, both for use in a hybrid production vehicle, such as the upcoming Q5 hybrid, and in the e-tron test platform.
The requirement specification for the concept vehicle goes far beyond battery technology and the replacement of the combustion engine with an electric drive system, however. The Audi development engineers decided back in the concept phase to design practically every component and technology based on the new requirements of electric mobility. The interaction of all elements has a decisive influence on the factors efficiency, range and practicality.
The Audi team therefore focused its attention on the total vehicle, which is reflected in the comprehensive requirement specification.
The reduction of road resistances and the resulting increase in range plays a major role with electric vehicles. Lightweight construction was therefore a top priority for the e-tron concept car. The body, in particular, combines low weight with supreme strength and rigidity. An intelligent aerodynamics concept with active elements helps to reduce consumption.
The package ensures the safe integration of the electric drive system and the battery. Placing the battery in front of the rear axle ensures an optimal axle load distribution without compromising the compact overall design and the generous amount of interior space.
Advanced battery technology enables a practical range. The battery system is water-cooled for optimal performance and service life.
A needs-based energy management system controls all functions for the chassis, convenience equipment and other auxiliary consumers.
The innovative thermal management system with optimally matched cooling and heating components considers the cooling requirements of the battery and the drive system in addition to the interior temperature.
Driving dynamics and road comfort are what Audi customers have come to expect in the sports car segment.
Vehicle safety is on par with the best of today's production vehicles.
The driver is provided with clear and comprehensive information.
The e-tron concept car uses car-to-x communication technology developed by Audi to improve the efficiency of conventionally powered vehicles. For example, information about traffic light cycle times and the flow of traffic - provided by the infrastructure and other vehicles - is used to compute an optimal driving strategy. Audi has already modeled such a solution in Ingolstadt as part of its "travolution" project.