Schematic process of inductive charging. © Wiferion

In addition, the swapping process ties up valuable vehicle and personnel capacity. If charging takes place via sliding connections, complex wiring and lowering kinematics are required to activate the contacts only at the time of charging. Otherwise, unwanted current flow and sparking can occur. These solutions are relatively expensive, inflexible, prone to faults and require structural intervention in the infrastructure.

Guidance systems: inductive, but expensive and inflexible
When AGVs are used in guidance systems, the vehicles follow a fixed track. Charging is inductive; however, extensive intervention in the infrastructure is required to install the conductors in the ground. The route must be permanently supplied with energy. The system is very costly and maintenance-intensive. There are also safety risks for employees, as a magnetic field is constantly generated. Guidance systems are relatively inflexible and can only be adapted to changing requirements with great effort. Every fleet expansion or route change becomes a problem. The efficiency of guidance systems rarely exceeds 60 percent.

Uninterrupted work processes thanks to in-process charging
Intelligent point charging systems with contactless energy transfer for charging lithium-ion batteries offer numerous technical and economic advantages. With the EtaLink series, Wiferion has developed a contactless fast charging system based on the principle of electromagnetic induction that enables intermediate charging with high currents.

The fast charging system from Wiferion is quick to install, maintenance-free and flexible to integrate. © Wiferion

The system consists of a stationary transmitter unit and receiver electronics on the vehicle side. The patented charging technology includes a wallbox and a charging pad. The receiver electronics with receiver coil, mobile charging unit and energy storage unit are installed in the vehicle. The charging process begins fully automatically within one second of the vehicles reaching the charging pad. This in-process charging opens up completely new automation and production concepts. The transmitter unit can be installed quickly and easily at neuralgic points in the warehouse, for example on frequently used routes or at loading and unloading stations. This means that even the shortest downtimes can be used for charging. Work processes no longer have to be interrupted by charging processes and long charging breaks are no longer necessary. This increases availability by up to 30 percent and the vehicles can carry out their tasks 24/7. If processes or other requirements change, the system can be quickly adapted and conveniently repositioned.

Reduce battery capacity and increase efficiency
If the lithium-ion battery is temporarily charged during several short stops and supplied with a high charging current, the energy level never drops but remains constantly high. Only a small capacity range of the batteries is required to operate the vehicles. This allows the capacity of the battery used to be reduced by up to 30 percent - an enormous cost advantage. The efficiency of the fast-charging system results in only low thermal losses and enables a compact vehicle design. Integration into AGVs is based on the plug-and-play principle. Existing vehicle fleets can also be easily converted. The charging stations can be used by different types of vehicles, whether driverless transport systems, industrial trucks or smaller electric vehicles. Depending on requirements, systems with 24 volts or 48 volts are available.

The elimination of plug and sliding contacts also increases safety compared to previous charging systems. The in-process charging solution is completely maintenance-free and quick to install. No intervention in the infrastructure is required. No separate rooms, battery changes or additional batteries are required for the charging processes. The charging system has real-time data acquisition and therefore enables constant monitoring of the operating status. Any faults are transmitted to the fleet management system via the CAN bus. This allows possible vehicle failures to be predicted and prevented by taking appropriate measures.

With an efficiency of 93%, modern wireless charging systems are as efficient as the most powerful wired charging solutions. As a result, process-parallel charging meets the requirements for a fully automated, maintenance-free energy supply and could soon replace the current charging standard in intralogistics. The high availability of the system leads to a significant increase in the reliability and process efficiency of logistics and production facilities. as