The present invention relates to an electric vehicle charger, and particularly to an electric vehicle charger with a reel I drum for coiling a cable when not in use.

BACKGROUND TO THE INVENTION

Some electric vehicle chargers, especially those in public places such as service station and supermarket car parks, have a charging cable with a charging plug permanently attached. When not in use, the cable is typically loosely coiled and hung up. However, in such a position cables are vulnerable to damage and possible vandalism or theft.

Some chargers, especially those designed to be installed for example on residential driveways, have no charging cable permanently attached. When a user needs to charge their car from one of these chargers, a cable needs to be plugged in to the charger at one end and the vehicle at the other end. The cable can be stored, for example, in the boot of the vehicle when not in use. This avoids leaving the cable exposed. However, it is inconvenient for a user to have to get the cable out and plug it into the charger every time they need to charge. For a physically disabled driver, this could be especially difficult or even make it impossible for them to plug in their car for charging without assistance.

Cable reels, for example extension leads, are well known. A long cable can be wound onto a drum, and the required amount of cable can be extended from the drum for use. However, cables carrying a high current heat up, and with a cable wound onto the reel the heat will accumulate and possibly damage the insulation on the cable. Typically, manufacturers will recommend that the entire cable is spooled out from the reel before use. However in reality this instruction is unlikely to be followed closely by many users, since having to unspool the whole reel defeats part of the object of having a reel in the first place, which is so that a desired amount of cable can be spooled out with the rest left safely out of the way.

It is an object of the invention to provide an electric car charger with a cable reel which solves these problems.

STATEMENT OF INVENTION

According to the present invention there is provided an electric vehicle charger, the electric vehicle charger including: a cable and a charging plug on an end of the cable; a rotatable drum having an outer surface; and an outer casing, the outer casing being disposed around the rotatable drum to define a void between the outer surface of the drum and an inside of the outer casing, and the outer casing having an aperture for allowing the charging cable to enter the casing, the cable in a stowed position being disposed in a coil around the outside of the drum, in which a further aperture is provided in the casing for allowing air into I out of the casing, and in which a fan is provided for directing air from one of the apertures, through the void between the curved outer surface of the drum and the inside of the outer casing, and out of the other of the apertures.

Advantageously, the fan ensures a flow of air from outside, between the inside of the casing and the outer surface of the drum. Air flows around the drum, preferably around at least two thirds, preferably at least three quarters, of the circumference of the drum.

A filter means may be positioned over the further aperture. Advantageously, the filter means substantially reduces or prevents water droplets and dust particles from being sucked into the casing by the operation of the fan.

Any desired length of cable may be dispensed from the drum depending on the requirements of the user, i.e. depending on where the vehicle is parked and where the vehicle charging socket is located in relation to the charger. Therefore, between the stowed configuration in which all the cable is wound onto the drum and a fully-deployed configuration in which the maximum length of cable extends from the casing, any intermediate length of cable may remain wound onto the drum.

A cleaning means, for example, a brush or wiper, may be provided adjacent the drum and in contact with the cable for cleaning the cable as the drum rotates.

Preferably, the aperture for allowing the charging cable to enter the casing is also large enough to allow the charging plug to enter the casing. Therefore, in a stowed configuration, the whole cable, including the plug, may be substantially protected by and concealed within the casing, protecting the cable and plug from damage and deterring theft and vandalism.

The outer surface of the drum is preferably a curved surface. For example, the drum may be substantially cylindrical with the outer surface of the drum being the cylindrical surface.

The end of the cable which is not attached to the charging plug will be connected to an electricity supply. It is understood that “charger” may encompass both devices which electronically control the flow of current to charge vehicle, in which case the supply to the charging cable is controlled in this way, and also devices which essentially provide for a cable reel to attach the charging plug to ordinary mains electricity. The connection of the cable the electricity supply is typically made inside the casing of the charger.

In embodiments, a baffle or wall is disposed to substantially block air from flowing through the shortest path between the two apertures. Air is thus forced around the longest path, covering a larger proportion of the circumference of the drum, and providing a cooling effect for any cable which remains coiled on the drum while the charger is in use.

Preferably, a controller is provided, the controller being adapted to turn on the fan automatically when the cable is uncoiled to allow charging, and/or when current starts to flow through the charging cable. In some embodiments, the fan may remain switched on for a predetermined period of time after charging is completed and the cable returned to the stowed position, coiled on the drum.

In some embodiments, a temperature sensor may be provided as an input to the controller. The temperature sensor may be used to switch on the fan when the temperature is greater than a threshold. Preferably, the fan is always switched on when the charger is in use, but the temperature sensor may be used to control the fan after charging is finished and the cable is returned to the stowed position, running the fan for as long as necessary until the temperature is reduced below a threshold.

The drum may include a helical cable guide. When the cable is wound onto the drum, the helical cable guide ensures that the cable lies in a single layer. Preferably, a cage is provided around the outside of the drum to further guide the cable. The object is to ensure that the cable lies in a single layer, across the whole axial extent of the outer surface of the drum when fully wound. By avoiding any crossing over, maximum surface area is achieved and this facilitates cooling. The applicant’s co-pending British application no. 2203016.7 describes a suitable cable reel configuration, which ensures that the cable lies in a single layer and reduces the possibility of riding turns or jamming.

In some embodiments, a further void may be provided on the inside of the drum. Slots or apertures may be provided in the drum for providing an air passage between the inside of the drum and the outside of the drum. By allowing air exchange between the inside of the drum and the outside, more effective cooling is achieved.

Optionally a retractable cover may be positioned over the aperture to further prevent the ingress of water droplets and dust particles. The cover may open in operation of the charger. The cooling fan may only operate when the cover is open.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made by way of example only to the accompanying drawings, in which:

Figure 1 is a perspective view of an electric vehicle charger according to the invention, with a cover removed; and

Figure 2 is a perspective view of the electric vehicle charger of Figure 1 , with the cover installed for use.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring firstly to Figure 1 , an electric vehicle charger is indicated generally at 10. The charger has an outer casing 12. In Figure 1 , the charger is shown with a cable 14 and charging plug 16 in a stowed configuration, which is with the cable 14 and plug 16 substantially enclosed within the outer casing 12.

The cable 14 is wound onto the outer surface of a drum 18. The drum 18 is rotatable, in this embodiment by means of a motor 20 which can be controlled to dispense or retract the cable 14 for use or stowage.

A cable guide 22 is provided around the outer surface of the drum 18. The cable guide 22 is in the form of a helical wall, extending perpendicularly from the outer surface of the drum 18. A cage, comprising a series of bars 24 extending parallel to the axis of the drum 18 in a “squirrel cage” configuration, surrounds the drum. An interior diameter of the cage is larger than an exterior diameter of the drum 18, forming a space between the outside of the drum 18 and the inside of the cage. Preferably, this radial space is a little larger than the diameter of the cable 14. The bars 24 of the cage, together with the helical cable guide 22, ensure that the cable when wound onto the drum lies in a single layer, and when fully wound covers substantially the axial width of the drum.

The drum 18 and cage is provided inside the outer casing 12, with a void between the inside of the outer casing 12 and the outside of the drum 18. The void extends around substantially the whole diameter of the drum 18, so that air can flow around the outside of the cable 14, when the cable is wound onto the drum.

An aperture 26 is provided in the casing 12 for allowing the cable 14 and in this embodiment the plug 16 as well to be extended out of the casing 12 for use, or to be retracted into the casing 12 for stowage when not in use.

Further apertures 28 are provided in the casing 12. The further apertures 28 are in the form of slots.

Both the cable exit aperture 26 and the further apertures 28 are substantially downward-facing, when the charger is installed in the position shown in Figure 1. The apertures or openings are all downward facing to minimise egress of water and dust into the charger.

Preferably, as in this case, the casing of the charger may be substantially cylindrical, with the central axis of the cylinder (the central axis running through the centres of the two circular faces of the cylinder) running substantially horizontally in use. Downwardly-facing apertures may be provided in the lower half of the cylinder, i.e. below the central axis.

The cable exit aperture 26 and the further apertures 28 may be provided so that there is a short path between the two apertures 26, 28, and a longer path. A wall 30 is provided in this embodiment to substantially block flow of air along the short path. This means that air being forced from aperture 26 to aperture 28 has to take the long path, which takes the airflow around well over half of the outer surface area of the drum 18.

A cleaning means, for example, a brush or wiping apparatus may be positioned adjacent the drum 18. The brush or wiping apparatus is in proximity to brush or wipe the cable located on the drum as the drum rotates. Dust and dirt collected by the brush preferably drops out through the cable exit aperture 26. Furthermore, the brush may be positioned to further block the airflow path, in proximity to the aperture 26, to the right-hand side as viewed in Figure 1. In other words, this enhances the flow of air further around the upper side of the cable and drum 18.

A fan 32 is provided in the long path between the two apertures 26, 28. In this embodiment, the fan draws air in from the underside of the fan as shown in Figure 1 , i.e. into the casing through slots 28. Air is then forced around the outside of the drum 18, through the void between the outside of the drum 18 and the inside of the casing 12, and out of the aperture 26.

Optionally a filter may be placed over the air intake apertures 28. This obviates the risk of water and dust particles being sucked into the casing 12 by operation of the fan 32.

Apertures, in this embodiment in the form of slots 34, are provided through the outside wall of the drum 18. These apertures allow air exchange between the inside and the outside of the drum. Preferably, apertures are provided at multiple points around the circumference of the drum. Air can therefore flow through the inside of the drum as well as around the outside, improving cooling performance.

A hub 36 at the centre of the drum 18 includes slip rings for providing an electrical connection between the cable 14 and an electricity supply. The slip rings allow the electrical connection to be maintained as the drum rotates. The hub 36 with slip rings is another point which may tend to heat up when high charging currents are flowing, and by providing airflow through the inside of the drum this heat can be safely removed.

Figure 2 shows the charger 10 fully assembled, with a cover 12a of the outer casing installed. When fully assembled, the outer casing is substantially cylindrical, with the cover 12a forming one of the circular faces. The other circular face is a back panel which could be mounted to a wall, or in some embodiments the whole of the casing may be supported for example on a post. The drum (18), inside the housing, may also be cylindrical, and the axis of the cylindrical drum may be parallel with the axis of the cylindrical casing 12. The axial extent of the drum may substantially match the axial extent of the cylindrical housing, in other words the drum fills substantially all of the axial width inside the housing. The void between the outside surface of the drum and the inside surface of the housing is therefore the radial space outside the drum.

Optionally a retractable door or cover may be positioned over the aperture 26. The retractable cover may move between a closed and open position. The door is closed when the charger is not in use. This further prevents the ingress of water and dust into the casing 12. When the charger is used, the door opens allowing for the spooling off and on of the cable through the aperture 26.

The actuation of the charger causes the door to open, and also may start the fan. When the door is open, the fan is operational to cool the cable 14. If any dust or water droplets are sucked through the filter by the fan, then they should be expelled through the open aperture 26 or cleaned off by the brush or wiper. When the door closes, the fan is turned off. This prevents contaminants being sucked in which cannot be blown out or wiped off the cable.

As shown in Figure 1 , a containment box 37 is disposed within the casing 12. The containment box sits underneath the drum 18, as viewed. The containment box 37 houses the electronics for controlling the charger. The containment box is substantially sealed in order to keep the electronics in a clean environment, further protected from dust and water ingress.

The invention provides for a charger in which the cable and plug can be retracted when not in use, and in which only a desired amount of cable can be dispensed according to the user’s needs, i.e. depending on where the vehicle is parked and the position of the charging plug on the vehicle in relation to the charger. This avoids an unnecessarily long cable run which may trail on the ground and create a trip hazard. Unused cable may remain stored on the drum, inside the casing of the charger. The cooling arrangement ensures that excess heat from the cable is safely managed.

The embodiments described above are provided by way of example only, and various changes and modifications will be apparent to persons skilled in the art without departing from the scope of the present invention as defined by the appended claims.