GB2522051A

GB2522051A - Method and system for charging electric road vehicles

Info

Publication number: GB2522051A
Application number: GB1400480.8A
Authority: GB
Inventors: Jeremy Chun Chung Lau
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-13
Filing date: 2014-01-13
Publication date: 2015-07-15
Also published as: GB201400480D0

Abstract

Electric road vehicles are charged while either stationary or moving along a roadway through electrical conductors 2 aligned in the direction of travel on a road surface. Electrically conductive brushes 3 extend downwards from a vehicle and make contact with the tracks 2. Power supply from the rails 2 to identified vehicles is triggered only when a series of precaution conditions are met, to ensure the safety of pedestrians. Weight sensors 1 are positioned either side of the rails 2 and detect the presence of a suitable vehicle; the vehicle itself can be identified through electrical signals transmitted through electrically conductive tyres to the weight sensors 1, where the signals are detected by control unit 9, which in turn controls power to the rails 2. A residual current device (RCD) disables power supply to the rails 2 if a leakage current to the surroundings is detected. To improve road drainage and safety, the tracks 2 may be positioned at the bottom of narrow channels (5, fig. 4) in the road surface.

Description

Method and System for Charging Electric Road Vehicles

TECHNICAL FIELD

This invention relates to charging of electric road vehicles from a power supply in the road.

BACKGROUND OF THE INVENTION

Replacing traditional petroleum fuel vehicles with electrically-driven vehicles is believed to be an important measure to reduce pollution and carbon dioxide emissions.

However, the use and popularisation of electrically-driven vehicles generally faces the difficulties of limited capacity of batteries carried by vehicles, long charging time and few charging locations. A guide-rail charging device for electric vehicles was developed, but the use is limited to fixed route vehide such as a public bus.

At least some known systems enable the charging of a moving vehicle using electromagnetic induction. There are obvious advantages over other systems of charging electric vehicles: they can charge a vehicle while it is moving on the road, thus reducing the size of on-board vehicle battery, and they can reduce the time needed to charge at a fixed charging station. However, there are several potential disadvantages. To transfer sufficient power to a vehicle may require a strong electromagnetic field which may result in energy loss and wastage. It may also pose greater health risk as an electromagnetic field may be possibly carcinogenic and increase the chances that children may get brain and other types of cancer.

Furthermore, the technology requires a precise alignment between the on-board battery and the charging facility.

The present invention overcomes the above difficulties by providing a system for charging static or moving electrically powered vehicles on roads using traditional conductors. A number of precautions are provided to reduce the possibility of electric shock to other objects on roads.

SUMMARY OF THE INVENTION

The invention provides for a system and a method for charging an electrically powered vehicle. This invention may be used to transfer power to a static or running electrically powered vehicle, which may include a heavy duty vehicle, such as a bus or truck, and a commercial vehicle which normally runs long hours, such as a taxi, The electrically powered vehicle can be a pure electric vehicle, a hybrid vehicle, or a the! cell vehicle. The invention cannot be applied to motorcycle, and accordingly a vehicle for use in the invention has four or more wheels.

One aspect of the invention provides for a road system that allows charging of electrically powered vehicles without any overhead charging conductor or line. The road system in this invention may be used to transfer power to an electrically powered vehicle. The key of this invention is the ways to trigger the power transfer from the road to vehicles only, without causing electric shock to other objects on the road. The road system contains a series of precautions that ensures that electric circuit is only connected with identified cars but not other cars or other objects on the road, thus allowing other road users, such as pedestrians, to walk or move safely on the roads.

Aspects and features of the invention will be apparent from the appended claims,

BRIEF DESCRIPTION OF DRAWINGS

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 shows the bird eye view of a normal road, with vehicle; Figure 2 shows the bird eye view of a road according to one embodiment of the invention; Figure 3 shows a cross section on 3-3 of Fig, 2 illustrating the design of the vehicle and road according to an embodiment of the invention; and Figure 4 shows a detailed design of the touching plates in a road modified for the invention,

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

In this invention, beneath the electric vehicle is a pair of brushes (3) that touch the surface of the road. The brushes may be made from copper wire to transmit an electrical charge from the road to the vehicle, The two brushes (3) form the two poles in an electric circuit. The pair of brushes, when coming into contact with the conducting component (2) laid on the road, closes the electric circuit between the vehicle and the power source from the road while allowing the vehicle to move freely on the road, Another aspect of the invention provides for a mechanism that enables the road system to identifV vehides that are designed according to this invention, to switch on the power supply from the road system and to transfer electricity only to identified vehicles.

This invention contains several precautions that prevent the leakage of electricity. The power source of the road system is switched on only when all the precautionary conditions are met.

In one preferred embodiment of the invention (precaution number 1), pairs of strip-like weight sensors (1) are paved on the two sides of a road lane, running parallel to the direction of lane. The strip-like weight sensors (1) are embedded on the surface of the road such that vehicles can run on the weight sensors. When two wheels of the vehicles press one pair of weight sensors (1) simultaneously, and when the weight exerted on the weight sensor (1) exceeds a specified limit (indicating that the object on the road is a qualifying vehicle), the precautionary condition 1 is met.

In another embodiment of the invention (precaution number 2), the road system can identify different cars through the electrical signals transmitted from the electrically powered vehicles through their tyres. Tyres are normally made of rubber and are not electrically conductive, However, in this embodiment the tyres of the front wheels (4) are made of conductive rubber. A small power unit in the vehicle generates a low power current (<10 watts). When the conductive rubber (4) presses on the weight sensor (1) which is also made to be electrically conductive, the low power current is transmitted through the conductive tvres to the weight sensor when the weight sensor (1) is not activated, the power supply ceases.

The current is detected by a central unit connected to the weight sensor. The current generated by the car and received by the central unit is one of the precautions preventing the power supply from the road from switching on and leaking electricity to other objects on the road. The low power is designed to ensure safety such that, when someone comes into contact with the tyre (4) or the weight sensor (t), the current should not cause any damage.

In another embodiment of the invention (precaution number 3), the power supply from the road system is equipped with a residual-current circuit breaker (RCD). If there is a leakage current to the surroundings, the residual-current circuit breaker will open the circuit to disable the power supply, thus preventing injury caused by electric shock.

Under each pair of weight sensors there is a control unit (9) connecting to the weight sensors (t), the conducting plates (2) and the main power supply, The RCD is located in the control unit. The control unit ensures that power is connected to the conducting components (2) when all of the precautions 1, 2 and 3 are met.

The other preferred embodiment of the invention (precaution number 4), lies in the design of the conducting component (2) on the road surface. The conducting component placed on the road surface is the contacting point with the brush (3) fixed beneath the electrically powered vehicle and forms a complete circuit when the brush touches the conducting component. However, instead of a flat surface mounted metal plate, a conducting plate (6) is placed at the bottom of one or more long and narrow channels (5) running parallel to the direction of the road. When an electrically powered vehicle mns on the road, the pair of brushes (3) installed beneath the vehicle touches the touching plates (6) at the bottom of the channels (5) on the road. The electric circuit is closed and the electric car can draw electricity from the touching plate (6) to charge the electric car and its battery. A cross-section is illustrated in figure 4. The design of the touching plate (6) serves three purposes: i) to prevent objects other than brushes touching the electrically charged metal plate; ii) drainage; iii) to preserve friction on the road surface (7). The width of the channel (5) could vary from 10 mm to 30 mm. The channel design prevents other objects from coming into contact with the touching plate (6) and causing an electric shock should all of the precautions 1, 2 and 3 fail.

Inside the channels are drainage holes (8) that keep the channels and contacting plate free of water. A sound and efficient drainage system should be installed to duct water away from the touching plates to enable all-weather operation of the road charging system. The outermost channels may be deeper (as illustrated) to permit water to drain away. Such channels may be connected to conventional road drainage systems.

To maintain good conductivity of the touching plate (6), it may also coated with materials to repel water, dust, oil, and/or dirt.

At all times when the precautions 1, 2 and 3 are met and when power supply is connected to the conducting components (6), the conducting components (6) are covered by the vehicle entirely, preventing humans and other objects from coming into contact with the conducting components (6).

The advantages of the invention include: I. Simple and proven technology As compared with other systems that enable the charging of a moving vehicle using electromagnetic induction, this invention makes use of simple technology and engineering. There is no uncertainty in health risks.

2. Low cost and high efficiency The key of the invention is prevention of power leakage causing electric shock and injury. Therefore there is almost no power wastage, leading to low operating cost and high efficiency.

In one embodiment of the invention all of the precautions 1-4 may be required for power to be connected. However, the precautions may be used in any lesser combination, or a single precaution may be used if appropriate. In other words a single precaution may be deemed sufficient, or a combination of two or three precautions may be sufficient.

It is anticipated that modifications and changes will be possible within the scope of the appended claims.

S

Claims

Claims I. A charging system for electrically powered vehicles, and comprising: strip-like sensors on a road, said sensors being aligned with the direction of travel on the road and being adapted to sense the weight of a vehicle to enable a power supply; electrical conductors of said power supply on said road, aligned with said direction of travel; and flexible electrical conductive brushes extending downwardly from a vehicle for contact with said conductors.
2. A system according to claim I wherein said conductors are water repellent.
3. A system according to claim 2 wherein said conductors comprise a metal touching plate having a water repellent coating.
4. A system according to any preceding claim wherein said conductors are provided at the base of channels in the surface of said road.
5. A system according to claim 4 wherein said channels include openings for drainage of rain water.
6. A system according to claim 5 wherein said openings are connected to a road side drain.
7. A system according to any preceding claim and further including a residual current device (RCD) for controlling supply of power to said conductors.
8. A system according to claim 7 and including a vehicle having tyres of conductive rubber.
9. A system according to any preceding claim, and comprising a vehicle having two laterally spaced brushes depending therefrom.
10. A system according to claim 8 wherein said brushes have multiple filaments.
11. A method of charging an electrically powered vehicle using the system of any of claims 1-10, and comprising: positioning said vehicle on said road, contacting said brushes and conductors, and enabling said power supply by sensing that the weight of said vehicle is above a predetermined minimum weight.
12. A method according to claim 11, including the ifirther step oil detecting an earth leakage current via the tyres of said vehicle, and disabling said power supply if said earth leakage current exceeds a predetermined value.
13. A system substantially as described herein with reference to the accompanying drawings.
14. A method substantially as described herein with reference to the accompanying drawings.