High-voltage batteries from discarded electric cars can still be put to good use even after years of use on the road. AUDI AG and EnBW Energie Baden-Württemberg AG are now taking advantage of this in a joint project with a stationary battery storage system for so-called second life batteries that come from dismantled Audi test vehicles. The system is intended to store electricity from renewable energies, compensate for fluctuations in the power grid and thus contribute to security of supply. Together with State Transport Minister Winfried Hermann, the two cooperation partners officially commissioned the pilot plant today on the EnBW power plant site in Heilbronn.
Transport Minister Hermann said during the event: “The commissioning of the battery storage facility once again impressively demonstrates that the mobility and energy transition can only succeed together. Battery storage is indispensable for a successful energy transition. Making discarded batteries from e-cars part of an electricity storage system is a very promising approach. The electricity generated from renewable sources can be stored temporarily and the systems do not have to be disconnected from the grid in the event of an oversupply. This way we achieve optimal use of renewable energy and valuable resources are used for even longer.”
Storage consisting of twelve batteries with a plug & play approach
The new battery storage system in Heilbronn consists of twelve high-voltage battery systems taken from disassembled development vehicles. Connected together, they have a total output of one megawatt (MW) – this means that the storage system, which is ready for immediate use, could cover the electricity consumption of around 3,000 households for about one hour. What is special about it is a “plug & play” approach with which the vehicle batteries can be easily and thus very cost-effectively interconnected to form a storage system. The system serves as a reference for initially four projects that are currently planned at EnBW for the near future.
Compared to their first life, the HV batteries are used with significantly lower and more even currents in the second life application. The stresses are thus significantly lower than in mobile use, where a lot of energy has to flow very quickly for acceleration. Those responsible for the project therefore assume an operating time of at least five to ten years for the second life of the cells. After that, Audi will finally recycle the batteries. This involves breaking them down into their individual components and raw materials so that they can be used again in new batteries in the future.
Focus on grid stability and energy market activities
In the coming weeks, the performance of the storage unit will first be tested and various application scenarios simulated. These include, among other things, operation to provide balancing power, i.e. the release of energy when the grid frequency is too low because not enough electricity is being fed into the grid. And conversely, the storage of energy when wind or PV plants feed so much power into the grid that the frequency rises too much. In addition, it is being investigated how the storage capacity can be used on the energy market – depending on the availability of cheap electricity from renewable sources. In the future, it should also be interesting for municipal utilities, industrial companies or operators of decentralised generation plants to use storage from used battery modules: Because their use is both sustainable and economical. More about intelligent battery storage systems at: www.enbw.com/batteriespeicher