The remaining charging capacity of a lithium-ion battery after use in a car is more than sufficient for the requirements of material handling vehicles. (Photo: Audi)
Audi is testing factory vehicles powered by used lithium-ion batteries at its main plant in Ingolstadt, Germany.
Like all automobile manufacturers, Audi is obliged by law to take back energy carriers after they have been used in cars. Because they still have a large proportion of their original charging capacity, an interdisciplinary project team is now investigating how batteries from Audi e-tron test vehicles or from hybrid models such as the Audi A3 e-tron and Audi Q7 e-tron, can continue to be used.
Factory vehicles in Audi’s production plants, such as forklifts and tow tractors, have so far been powered by lead-acid batteries, with their long-charge times, and awkward removal processes. Lithium-ion batteries, by contrast, can be charged directly where the vehicles are parked during normal downtimes, in breaks between shifts, for example. This saves battery room space and eliminates the high manual effort required to replace the batteries.
Audi estimates it would save millions of dollars if it converted its entire fleet of factory vehicles to lithium-ion batteries at its 16 production sites worldwide.
“Every lithium-ion battery represents high energy consumption and valuable resources that must be used in the best possible way,” said Peter Kössler, member of the board of management for production and logistics at AUDI AG. “For us, a sustainable electric-mobility strategy also includes a sensible second-use concept for energy carriers.”
The remaining charging capacity of a lithium-ion battery after use in a car is more than sufficient for the requirements of material handling vehicles. Their driving characteristics actually improve considerably: They can keep their speed constant even on ramps – vehicles powered by lead-acid batteries cannot do that. In addition, regular charging during breaks prevent downtime during working hours.
The battery of an Audi e-tron consists of 36 individual battery modules and is located under the car’s passenger cell between the axles, in the form of a flat, wide block. After batteries are taken back, the project team checks each individual module for its continued usability. They then install 24 modules in each new battery tray. This has the same dimensions and weight as the previous lead-acid batteries of the factory vehicles, so the company can continue to use all of those vehicles without any major investments.
In the future, Audi sees the possibility of a team of specialized employees that could take over the assembly of the second-use batteries in the company’s own battery centre.
A project team from production, logistics and development has been working on this second use of used battery modules for about two years. After the first tests were successful, they are now testing the first converted factory vehicles in everyday production.
Audi is also looking at the possiblity of using used battery modules in mobile charging containers for electric vehicles or in stationary energy-storage systems.
Audi is also developing recycling concepts: At the end of the battery lifecycle, valuable elements can be recycled into new products.