"The race for the most efficient wireless charging technology is in full swing. Because it could make the charging process as convenient as with cell phones.
The idea is simple: the electric vehicle is parked in the garage or public parking lot over a flat charging coil, which automatically transfers electrical energy without a physical connection. With a view to the future of autonomous driving, this type of charging option is needed without human intervention. In particular, autonomous valet parking, which will be part of parking in metropolises or airports in the future, would offer even greater added value for customers.
Early beginnings
However, inductive charging was quiet for a long time, and there were many reasons for this. But one of the main reasons so far has been a lack of standards in the industry. Automobile manufacturers such as Mercedes, BMW and Tesla have been working on their own solutions for inductive charging for several years. Mercedes-Benz developed the S550e plug-in hybrid in collaboration with Qualcomm back in 2017. BMW started production of the 530e iPerformance plug-in hybrid similarly early and supplied both the vehicle-side charging module and the external charging module. Last year, Tesla took advantage of the innovative know-how of the German start-up Wiferion, which specialized in inductive charging. In addition, Tesla recently confirmed that it is continuing to work on a solution for inductive charging, particularly with regard to autonomous vehicles.
Breakthrough is imminent
However, cross-manufacturer solutions are needed for widespread distribution. The breakthrough now doesn't seem to be long in coming, as inductive charging is about to be ready for series production with a standard developed by the German company Mahle from Stuttgart and could be on the road in a few years. The American standards institute SAE International recently designated the Mahle system as the global standard solution for wireless charging.
The road as a loading route
However, this is not the end of inductive charging. In Germany, work is already underway on the next breakthrough innovation in inductive charging. This promises automated inductive charging while driving on electrified roads that are equipped with induction coils. The efficiency at the stage of development is already well over 90 percent and is therefore even superior to wired charging, especially if the electrochemical energy conversion in the battery can be eliminated.
According to current standardization efforts, a power of 60 kilowatts can be transmitted per pair of coils. This means that when you drive one kilometer, the energy could theoretically be charged for a range of around two more kilometers. German research institutes have built up industry-leading know-how particularly in the automation of production processes for the coils laid in the roadway and for the control cabinets provided along the highways, as well as in the industrialization of road construction for electrified roads.
Less battery weight in the truck
Heavy trucks could also be charged on electrified roads. The additional weight caused by large batteries has previously been a major obstacle to the electrification of heavy-duty transport. Dynamic inductive charging means that a smaller and therefore lighter battery can be used. Advantages that dynamic loading of trucks via overhead lines also offers. However, since dynamic charging can be used on electrified roads by cars and trucks, the number of users of this technology is higher. And the higher the possible number of users for a new technology, the higher the probability that a new technology will become widespread.
High costs for expansion
The question remains whether such a seemingly futuristic technology can be financially realized. The construction costs of the above-mentioned charging solution via overhead lines of 4 million euros per kilometer of overhead lines and annual maintenance costs of almost 300 million euros ultimately brought the electrification of the motorway via overhead lines to a standstill.
For this type of electrification to have a maximum effect, all German motorways would have to be equipped across the board. According to current calculations from leading technology providers, the cost of electrifying one kilometer using induction coils is around 1 million euros. Given the total length of around 13,000 kilometers of motorways in Germany in two directions, this would mean an investment of almost 30 billion euros. Planning the expansion into regular streets According to current estimates, renovations every 10 years could be carried out with an annual budget of 3 billion euros to modernize the entire infrastructure over a period of ten years.
A 6 as a test field
Test routes are currently being developed internationally to evaluate contactless energy transmission. In Germany, corresponding research projects take place in Cologne, Karlsruhe, Mannheim and Balingen, among others. From 2025, contactless energy transmission will also be tested for the first time on a German motorway, the A 6 between Nuremberg and Amberg.
If the ongoing research projects meet the high expectations of technical performance, ecological compatibility and economic feasibility, an innovative key technology in electromobility could be occupied by local companies. However, as with all infrastructure projects, clear political guidelines and standardization processes are necessary.
Prof. Dr.-Ing. Jörg Franke is the holder of the chair for manufacturing automation and production systems at the Friedrich-Alexander University Erlangen-Nuremberg." [1]
1. Drahtloses Laden als nächste Sprunginnovation in der Elektromobilität. Frankfurter Allgemeine Zeitung (online) Frankfurter Allgemeine Zeitung GmbH. Feb 14, 2024. Von Helena Wisbert und Jörg Franke