Wireless Charging

Nikola Tesla invented the first system for transmitting energy through the air in 1893. He did this using the principle of induction discovered by Michael Faraday at the start of the 19th century. In 1961, General Electric sold the first toothbrush that could be charged wirelessly via induction. In 1996, General Motors fitted its electric vehicle EV1 with so-called induction paddles, but later removed the model from the market prematurely. The technology upon which wireless energy transmission is based is therefore nothing new – but it has only been applied to electric vehicles relatively recently. However, the principles are still the same.

In light of the very ambitious targets that car manufacturers are setting with regard to the electrification of a significant proportion of their future models, suppliers would be well advised to arm themselves with innovative solutions to meet the upcoming demand. “We are convinced that there are unique opportunities for our company in the field of wireless charging technology. We are going to make the most of these opportunities,” says Johannes Biermann, Head of Product Line Wireless Power Transmission. As a specialist in the development and production of product solutions to protect the vehicle underbody, Röchling Automotive stands out from its competitors with fully integrated solutions. Product development involving integrating components for wireless charging directly into intelligent underbody systems seems to be the obvious way to go. The result is state-of-the-art charging technology for electric vehicles – and added value for the customer. This technology does not require any visible infrastructure in the form of charging stations, as is required for cable-based charging. The transmitter coils for charging are laid in the ground, where they are protected against weather influences and possible vandalism. This also means that there are no freely accessible and live components.

Transmitters and Receivers
The idea behind wireless charging is easy to explain: a transmitter coil with a special enameled wire, the so-called primary coil, is mounted in a housing (“park pad”) on or in the ground. Alternating current is then conducted through the coil, creating a magnetic field. The electric vehicle itself is fitted with an ultra-thin receiver coil, the so-called secondary coil, inside the vehicle underbody. This vehicle coil is then positioned within the magnetic field of the primary coil using a positioning aid. The transmitter and receiver are separated by an air gap. This induces an electrical current in the secondary coil, which is transmitted to the battery. Voilà – the electric vehicle is being charged wirelessly.

The structure of the charging device is essentially the same as for cable-based charging devices that are already being used around the world: a wireless base charging station is connected to a 220/240-volt network. This base station is connected to the primary coil for energy transmission via a power cable. The coil is positioned wherever the electric vehicle is usually parked (home charging) or left for charging (semi or fully public area). The wireless park pad converts the incoming electrical power from the mains network into magnetic energy that can be transmitted safely to the receiver coil via an air gap. This is integrated into the underbody of the vehicle. The receiver then converts the magnetic energy back into electrical energy.

Röchling Automotive is currently implementing various measures in order to position itself as the supplier of choice in the field of wireless charging and has also established a team to work specifically on this topic. The team is not only conducting its research in the global Technical Centers of the company, but also in a wireless power transmission (WPT) hub, an innovation center set up in a garage in the Worms plant, Germany, giving it the atmosphere of a start-up. “As a supplier of system solutions, we will be able to supply systems that precisely meet the requirements of the respective OEM customer in all regional markets,” says Biermann. Asian customers may request products with different properties than customers in the USA or Europe – and Röchling Automotive is the right partner for them all.


Johannes Biermann

Röchling Automotive, Head of Product Line Wireless Power Transmission, Product Area New Mobility

Phone: +49 6241 844-423


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