Charged with innovation
At the heart of every electric vehicle are its powertrain and battery – a powerful muscle that keeps the vehicle moving, and whose performance determines the car’s range. Recent developments in the field of lithium-ion battery technology have ensured that electrically powered mobility has progressed from short to long distances; the fully electric series models that Audi will soon be launching will have a maximum range of up to 500 kilometres (NEDC).1 The company’s own High Voltage Competence Centre near Ingolstadt is playing an important part in achieving such long-distance compatibility. It focuses on developing the complete system, which means packaging, cooling, fusing and – in collaboration with bodywork developers – integrating it into the vehicle. The most important aspect of this is the stiffness of the battery system and its behaviour in the event of a crash. Testing is done using forces of up to 150 g. Other key areas involve speeding up charging and slowing down the ageing of batteries.
“What’s special about our forthcoming fully electric series vehicles is that we have developed and produced the entire battery. In the past we relied on products made by external partners, such as those used in our plug-in hybrid vehicles. Now that’s changing. Our big lithium-ion battery can store 95 kWh of energy and is fitted at an ideal mass centre position beneath the passenger compartment,” explains Andreas Nöst, Head of Development E and E HV-Battery Storage Systems at AUDI AG.
Battery manufacturing in Brussels
Another important location is Brussels.
In 2018, a factory in the Belgian capital will begin to produce Audi’s first purely electrically driven SUV, which is based on the Audi e-tron quattro concept. It has an electric motor instead of a combustion engine and a battery instead of a tank. There will be a dedicated battery assembly facility in Brussels, where employees build the battery casing, install the cell modules and fit the cooling system. The battery is then fitted with a management system. But unlike the Competence Centre near Ingolstadt, this facility will not focus on the development of battery technology, it will prepare batteries to be wedded with vehicle bodies. Once the vehicle’s technical and power unit are fully assembled, the battery system is installed. This process is carefully timed and fully automated.
“The series version of our fully electric SUV will be made at our Brussels factory, where we’re also setting up our own battery assembly facility. This means the production of vehicles and batteries can happen side by side. As soon as the vehicle goes onto the production line, we can begin to manufacture its battery. This process is called just-in-sequence production,” explains Nöst.
Concept for used batteries
“Our development focuses on an integrated approach, which is what makes the field such an exciting one – today and tomorrow.”
Audi is not only busy with developing and fitting batteries for its vehicles; it is thinking a step further. Once a battery’s life in a vehicle is over, another important question arises: how can the battery be used from then on? The rechargeable cells still have capacity left in them – too much to simply recycle them. That is why Audi is working on a concept that converts used batteries into stationary energy stores. The first experimental system has already been connected up near Ingolstadt. A container for four traction batteries of varying sizes works in conjunction with a photovoltaic system which can generate up to 20 kW of power on sunny days. A second container houses the connection and control equipment, whose power electronics convert direct current from the batteries into alternating current at a constant 400 Volts. Once the batteries have dropped to ten percent capacity, they are recycled.
“Innovative storage platforms like this one provide suitable power sources for quick-charging stations with more than 250 kW of power. Alternatively, they can be used as buffers for renewable energies like wind and solar power – in the mains network or at customers’ homes,” adds Andreas Nöst. “Our development focuses on an integrated approach, which is what makes the field such an exciting one – today and tomorrow.”