E-Mobility Engineering 015 l EMotive Scarab off-road truck dossier l In Conversation: Giulio Ornella l Hall effect and magnetic sensors focus l Challenge of batteries for heavy-duty EVs l Alpha Motor Corporation digest l Automated charging insight l HVAC systems focus

The combination of these not only allows the robot to carry out the charging process autonomously but also to move around freely in the parking area, to recognise possible obstacles and react to them. Depending on the size of the parking area or car park, several charging robots can be deployed simultaneously so that several vehicles can be charged at the same time. Volkswagen has worked with robotics supplier Kuka on the robotic arm that connects to the vehicle being charged. Automating underbody charging Some developers are working on other systems to provide automatic connection devices for EVs from underneath the vehicle. Volterio for example has developed a low-profile robot that sits underneath a vehicle and moves around to provide the connection. The system consists of an onboard unit in the car‘s underbody and ground-based charging robot, with a comms system between the two. The key is the design of a self- centring, high-power 360º connector, which ensures that the angular orientation of the parking EV does not matter. The charging robot can handle parking misalignments of 40 x 40 cm. The ground unit starts automatically to communicate with the EV’s onboard unit via a secure wireless LAN connection when approaching. When charging is requested, the ground unit automatically connects to the vehicle unit in the car’s underbody, guided by an ultrasound-based micro-navigation system. The charging process starts automatically or can be scheduled by an intelligent charging management. The ground unit measures only 800 mm long, 420 mm wide and 68 mm high, and is automatically recharged. The company is also planning a version that can be embedded flat into the ground. Connector standard for automated underbody charging Although Prodrive has developed a range of wireless charging systems, it has also branched out since 2018 into automated under-vehicle charging. “It’s less complicated to do charging with a robotic system [rather than wireless],” says Nilles Vrijsen at Prodrive. “To integrate everything into one system with all the high magnetic fields and the detection systems and safety systems is a challenge for wireless, but a robotic system is more robust. We are now looking at commercial vehicles, as the real added value of automated charging is in these applications, where vehicle availability is important.” Prodrive’s system uses a 50 cm robot arm from the ground unit to lift the connector up to the vehicle. A drawer then opens up on the underbody of the vehicle to accept the connector and draw it in to make the connection. This reuses the same pins and plugs from the CCS2 connector on the side of the vehicle, but using the drawer approach reduces any misalignment and keeps the connector safe and secure. “With one sliding motion it is possible to align the connector by the shape of the connector and the drawer,” Vrijsen says. This also helps with safety, as the connector stays locked in the drawer until charging has finished. The robot arm features an encapsulated magnetic field system for positioning. “We didn’t want to make it a camera system, as that is more expensive, and we have experience in the magnetic fields from wireless charging,” Vrijsen says. The field system uses a 125 kHz transmitter coil with some modulation on the signal to subtract interference that comes from the metal in the underbody of the vehicle, and Prodrive is patenting this. “We found a way to compensate for the signals from the metal in and around the car by filtering this out,” Vrijsen says. Vrijsen is chair of the CharIN ACDU underbody group, which is starting the standardisation process for the connector and the rest of the system. “We are designing a connector comparable to the CCS2’s power range,” he says. “For underbody charging you have a different design envelope, you have a wider area but less height and you don’t interact with humans, so there are fewer safety issues.” The new connector is intended to support power levels up to 400 kW DC (500 A at 800 V) but that’s not the target for the whole system, as higher currents need thicker cables. Instead it is aimed at opportunity charging for commercial trucks around 22 kW AC charging and 150 kW DC charging in places where there is limited space for fast chargers, as well as comfort charging for disabled or elderly users. “Discussions on standardisation are ongoing for safety requirements of the ACDU system but the process has not officially started for the charging connector interface,” Vrijsen says. “In Germany they are preparing for this, and in CharIN we are having talks with suppliers preparing for this.” An underbody automated connection system (Courtesy of Prodrive) Autumn 2022 | E-Mobility Engineering 61 Deep insight | Automated charging