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Charging electric vehicles autonomously

Why the Underbody Charger could be the e-charging station of the future

Electric car using the Underbody Charger to charge its batteries

The fact that electric vehicles are too expensive, take too long to charge, can't drive far enough, or that a cable always has to be touched to charge them are arguments that still keep many customers from buying an electric car. But the development in terms of e-mobility is progressing rapidly - also at Schunk:

"Charging an e-vehicle will become as easy as refueling," our expert Ahmad Kamar is convinced. Since 2018, the product manager has been driving the development of the prototype of an autonomous fast charging system for electric vehicles.

Underbody solution charges electric vehicles within a few minutes

The so-called Underbody Charger is designed to allow efficient, safe and convenient charging of various vehicle types in just a few minutes. This is made possible by a Smart Charging system that can be retracted into the road surface, a docking module installed in the vehicle floor, and extremely high power transmission. This means that the automatic charging process can be shortened to just a few minutes, even when the batteries are completely empty, and can be easily integrated into the everyday use of the vehicles. The system could also be used in one's own garage, where it would enable safe and automatic charging. No need to touch cables!

This is how the Schunk Underbody Charger works:

Ahmad Kamar answers frequently asked questions (FAQ) about the fast charging solution

How long does it take to charge a car with the Underbody Charger?

Ahmad Kamar: Our goal is that with our underbody solution, an electric vehicle with a 100 kWh battery can be charged from 20 percent to 80 percent in less than 10 minutes.

What impact does fast charging have on the life of the car battery?

Ahmad Kamar: Our charging system is designed for the next generation of batteries. With today's battery technology, fast charging can actually damage batteries after a few years - assuming you use this type of charging exclusively.
For the future battery generation, however, fast charging will be the standard - and it is exactly for this battery technology of the future, which can be charged at a rate of 2, 3 or 4C, that the Underbody Charger is designed.

Underbody Charger2-1460x680px
The Underbody Charger consists of a charging system, that can be tracked in the ground, and a docking module installed in the vehicle floor.


Do you have to allow for a break between two charging cycles?

Ahmad Kamar: No, our system is designed to charge continuously and serve one vehicle at a time. This will also be the requirement in the future. For example, if there is a direct payment option at the charging station, the driver can continue driving immediately after charging and release the charging station for the next vehicle.


How can the charging system be installed in the garage at home?

Unlike at a public e-charging station, where the charging station is sunk into the ground, a low-cost solution could be adapted for the home to lay on the garage floor. The charging system can then be easily connected to the home wallbox or power supply.

What is the weight of the vehicle-side hardware?

Ahmad Kamar: For our series product, the weight will be two to three kilograms.

underbody-charger-system-ecarUnderbody Charger for autonomous fast charging of electric vehicles

Are you also planning to develop inductive, contactless energy transmission?

Ahmad Kamar: No, we are concentrating on conductive charging. There are three reasons for this:

  1. Conductive charging is our core competence. We have over 100 years of experience in this field.

  2. Charging power: we want to enable high-power charging with our system. This is not possible with inductive charging technologies or is very complicated and costly. The reason: Inductive charging requires a high power converter from AC to DC. Large and expensive components such as these are not desired by OEMs and are therefore of no interest to us.

  3. Charging efficiency: with inductive charging, a charging efficiency of 93 percent is only achieved in the very best case. That is a high line loss and therefore not economical.

What is the current project status?

Ahmad Kamar: We demonstrated our prototype Underbody Charger as part of the first pilot projects for autonomous driving and charging (Aula). Now, after extensive testing, we are in the process of further developing our initial concept. Currently, we are participating with three other partners in the Mega-Laden research project, where we are testing our product with e-truck fleets in a logistics center. Our goal is to demonstrate the underbody charging system in real logistics operations by the end of 2022.

The Underbody Charger is one of several smart charging systems for charging electric vehicles - from electric buses to mining vehicles. Are you interested in our underbody solution? Then feel free to contact our expert.

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Editors note: This post was originally published in May 2021 and has been updated for accuracy and comprehensiveness.


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