Förstudie om automatiserad sladdlös konduktiv laddning av elbilar

Gustavsson, M., Börjesson, C., Eriksson, R., Josefsson, M.
Type of publication: 

Easy and convenient charging of electric cars is a desirable characteristic. Automatic cable-free conductive charging from road surface to cars is a potential possibility for simplifying the everyday life for users of electric cars, as well as increasing the efficiency of taxis and car pools. Charging infrastructure for electric cars could utilize the recent development for electric road systems (ERS) in which electrical energy is transferred during movement from the road infrastructure to the vehicle for both propulsion and charging of battery.

RISE and Volvo Cars have conducted a study in order to evaluate the potential of using an ERS solution for automatic conductive energy transfer from road to electric cars that are stationary or moving slowly over short distances (e.g. queues). Expectations from automobile manufacturer point-of-view, use cases, general requirements, characteristics that influence requirement areas, potential hazards, as well as recommendations for structured future work on functional safety have been documented. Strengths, weaknesses and maturity readiness have been investigated for the Alstom ERS, Alstom SRS, Elonroad and Elways solutions. The work has also involved a comparison between conductive and inductive charging of cars.

It is an interesting future possibility for the automobile industry to use conductive energy transfer from road to electric cars that are stationary or moving slowly over short distances (e.g. queues). However, the studied solutions have today a low maturity in case of applications for cars, and continued development, especially of energy pick-up arms for cars, must be done before a conclusion of possibilities and potential can be made. Compliance to functional safety, user friendliness and easy availability are absolute requirements before a market introduction of a solution can be considered.

The following items are necessary to be managed by the solution developers in order to achieve a fruitful collaboration with the automobile industry, and before it is feasible to plan for implementations and demonstrations of conductive energy transfer from road surface to cars:

  • Specification of appropriate application areas where conductive energy transfer from road surface with high power makes a difference (e.g. taxi queues, car pool centrals)
  • ”Automotive-grade” energy pick-up with the right design
  • Functional safety (especially electricity hazards)
  • Standardization of public solutions initiated (or at least planned)

Despite the present low maturity, conductive energy transfer from road to electric cars is interesting due to the possibility of the following use cases:

  • Automatic fast charging with adjustable power for different vehicle types
  • Automatic charging at public parking places (e.g. at super market)
  • Automatic charging at private parking with no guidance and automatic driving
  • Automatic charging at places where cars are frequently fetched (e.g. car pool)
  • Automatic charging when driving in queues at a low speed (e.g. taxi)
  • Automatic energy transfer (propulsion and charging) from road to different vehicle types with different power requirements at higher speeds

The participants of this project believe that a mutual dialogue between the car industry and the developers of conductive rail solutions is necessary in order to further develop how automatic cable-free charging can be implemented in a good way for users of electric cars.

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