In-Road Slotted Conductor Rail for High Ground Impedance

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Solution Overview

Problem

Existing electric vehicle charging systems using in-road rails face safety issues due to insufficient impedance to ground, particularly during wet conditions, and there is a need for improved rail/slotted elements that ensure safe and efficient power transfer.

Innovation Solution

A slotted element with longitudinally spaced apart insulating elements and air insulation to maintain high impedance to ground, combined with heating means to remove moisture, and protective covering elements to prevent access, ensuring safe and efficient power transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ground conductors are provided to ground the rail/slotted element, then vehicle body voltage safety is improved, but impedance to ground becomes insufficient during wet/moist conditions

Engineering Contradiction:
Improvevehicle body voltage safetyVSAvoidimpedance to ground insufficiency
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The insulating elements are segmented into multiple discrete units positioned at different longitudinal locations along the electric conductor. This segmentation creates multiple insulation points rather than a single continuous insulation, thereby maintaining higher impedance to ground even when moisture is present, as not all insulating elements will be compromised simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Insulating elements are introduced as intermediary components between the electric conductor and the body portion. These intermediaries provide electrical isolation and maintain impedance to ground by preventing direct contact between the conductor and conductive body portion, even under wet conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If electric conductors are continuously insulated along their length, then impedance to ground is maintained, but device complexity increases

Engineering Contradiction:
Improveimpedance to groundVSAvoidinsulation structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of providing continuous insulation along the entire length of the electric conductor, insulation is applied partially at specific discrete locations. This partial action approach maintains sufficient impedance to ground by insulating at critical points where the conductor approaches or contacts the body portion, thereby reducing complexity compared to full-length insulation.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

Insulation is applied with local quality by positioning insulating elements only at specific longitudinal locations where electrical isolation is most critical. This localized approach optimizes impedance maintenance while minimizing the number of insulating elements required, thus reducing overall device complexity.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively increases impedance to ground, reduces the risk of live voltage exposure, and enhances the reliability of electric power transfer in wet conditions, supporting both stationary and dynamic charging applications.

Implementation Method 1

the at least one electric conductor is connected to the body portion by means of two or more longitudinally spaced apart insulating elements

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

heating means to remove moisture

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4663461A1Slotted element and system comprising such a slotted element
Publication Date: 2025.12.17 ELWAYS AB
  • EP4663461A1 patent drawingFigure 1~4
  • EP4663461A1 patent drawingFigure 5a~6
  • EP4663461A1 patent drawing

AI summary

Slotted element (1) adapted to co-act with a current collector of an electrically propellable road vehicle for supplying electric power to said vehicle, said slotted element being adapted to be located on, or to be at least partly recessed in, a ground surface of a roadway or a parking lot. The slotted element comprises an elongated body portion with at least one slot (3a, 3b) extending in a longitudinal direction of the body portion/slotted element. One or more of the at least one slot is each provided with at least one electric conductor (4a) therein, the at least one electric conductor being adapted to be put under voltage for supplying the electric power, wherein the at least one electric conductor (4a) is connected to the body portion by means of two or more longitudinally spaced apart insulating elements (5a1, 5a2).