Plug and socket for electrical vehicle charger

Abstract

This invention provides a plug and socket combination for connecting a charging cable (22) to a charging inlet of an electric vehicle (12, 30). The plug (25) comprises at least three wedge-shaped electrical contacts (201, 202, 203) separated by isolation barriers (230) and tapering out from a narrow top (205) to a point of maximum width (206), a clamping groove (220) being provided below the point of maximum width (206). The socket (35) comprises at least three clamps (311, 312, 313) having an open and a closed configuration and being biased to the closed configuration. An inner surface of the clamps (311, 312, 313) comprises a complementary electrical contact (301, 302, 303), shaped to receive and contact a respective one of the at least three wedge-shaped electrical contacts (201, 202, 203) of the plug (25) when in the open configuration. The clamps (311, 312, 313) further comprise a bottom protrusion (360), configured to engage with the clamping groove (220) of the respective wedge-shaped electrical contact (201, 202, 203).

Description

[0001]SP2953 - 1 - PLUG AND SOCKET FOR ELECTRICAL VEHICLE CHARGER Field of the Invention This invention relates to a plug and socket combination for connecting a charging cable to a charging inlet of an electric vehicle. This invention further 5 relates to a plug and a socket for use in such a combination and to a charging dispenser for electric vehicles comprising such a plug or socket. Background of the invention 10 In the last two decades, an increasing part of the worldwide vehicle fleet has been electrified. As the electric vehicle (EV) market currently operates, different vehicles are charged at different charging power levels and using charging plugs (and sockets) of various designs. 15 Charging power levels may, e.g., depend on the EV’s own battery capacity and power requirement or the user’s need to charge fast. Often, the charging equipment and service providers need to supply different charging systems to meet the various power requirement variants on the 20 markets. More recently, the electrification of the vehicle fleet started expanding to the market of larger, Class 6, 7, and 8 commercial vehicles. For example, trucks, construction equipment, agricultural vehicles, and mining 25 vehicles are introduced that partly or fully rely on a plug-in battery system to power their propulsion. Because such larger battery electric vehicles typically have larger, higher capacity, battery packs, the charging power levels used for charging them are typically higher than 30 the charging power levels for consumer vehicles. An industry taskforce that is currently working on a charging standard for large battery electric commercial vehicles has, for example, proposed an MCS (Megawatt Charging System) charger specification that defines three different levels of DC output power; 350 A for level 1, 1000 A for 5 level 2, and 3000 A for level 3. At a maximum voltage of about 1250 V, the connector is designed to operate at a power output of up to 3.75 MW. For ultra-fast charging of, e.g., mining trucks and electrified ships, charging power of up to (and above) 40 MW are foreseen. 10 Designing reliable and safe connectors that can be used for repeated charging at such high power outputs brings many new technical challenges. Large electrical contact areas are needed that continue to make full mechanical and electrical contact, also after a large 15 number charging events. For safety, direct contact with charged connector surfaces is to be avoided. The different electrodes of the connectors must be properly isolated from each other to avoid short circuiting due to the high electrical currents running through the electrodes. 20 It is an aim of the current invention to overcome at least some of the technical challenges posed by these new developments. Summary of the Invention 25 According to an aspect of the invention, a plug and socket combination is provided for connecting a charging cable to a charging inlet of an electric vehicle. The plug and socket combination comprises a plug with at least three wedge-shaped electrical contacts separated by 30 isolation barriers and tapering out from a narrow top to a point of maximum width, a clamping groove being provided below the point of maximum width. The socket comprises at least three clamps having an open and a closed configuration and being biased to the closed configuration. An inner surface of the clamps comprises a complementary electrical contact, shaped to receive and contact a respective one of the at least three wedge- shaped electrical contacts of the plug when in the open 5 configuration. The clamps further comprise a bottom protrusion that is configured to engage with the clamping groove of the respective wedge-shaped electrical contact. The wedge-shaped electrical contacts of the plug and the complementary electrical contacts of the socket 10 together provide for a large surface contact area through which high currents can be drawn. This is especially important for the high power ultra-fast electrical vehicle charging for which the now presented plug and socket combination may be used. The wedge shape of the plug 15 contacts helps the clamps to automatically and accurately align with the plug contacts while being pushed open by the widening body shape of thereof. The self-centering function of the wedge-shaped electrical contacts make this plug and socket combination very suitable for autonomous 20 charging systems, wherein a robotic arm may need to connect the connector plug or socket to a charging inlet of which the exact location may be unknown when the connection process is initiated. On top of the self-centering benefits of the plug 25 and socket combination according to the invention, the wedge shape of the plug contacts, together with the clamp’s biasing force into the closed configuration, causes the clamp’s bottom protrusion to automatically clean the contact surface of the plug contacts while the 30 connection between the plug and the socket is made. This self-cleaning effect is further enhanced by the full electrical contacts of the plug and the socket having a short gliding contact in the final moments of connection, just when the bottom protrusion of the socket slips into the clamping groove. With every connection or disconnection of the plug and socket combination, this short cleaning action by the two sliding electrical contact surfaces efficiently removes any oxidation that 5 may otherwise build up on the contact surfaces. As a result, the electrical contacts are kept clean automatically just by using them, even when used in dirty or humid environments. Preferably, the plug comprises a plug housing that 10 encloses the wedge-shaped electrical contacts and has an opening for receiving the socket, the narrow tops of the wedge-shaped electrical contacts facing the opening. The housing protects both the plug contacts from contamination by water or dirt from the plug environment, 15 and the environment (including the user) from electrical shocks and currents originating from the plug contacts. The opening at the top of the plug housing is needed to allow the socket to approach the plug and connect the clamps to the plug contacts. This opening may be 20 temporarily shielded when the plug and the socket are disconnected. Preferably, the plug housing is funnel-shaped, such that the shape of the plug housing helps to align the socket during the connection process. First, the wider 25 opening of the funnel makes it very easy to insert the socket into the opening of the plug housing. Then, when the socket contacts move closer to plug contacts, the narrowing funnel guides the socket contacts in the right direction. The added self-centering aspect of the funnel- 30 shaped housing makes such a plug even more suitable for use with an autonomous charging system. In some embodiments, at least one of the wedge- shaped electrical contacts may be a ground contact and the plug further comprises a data communication contact. In such embodiments, The ground contact and the data communication contact may be configured to be clamped by the same one of the at least three clamps. While high power, large currents will run through the other 5 electrical contacts, virtually no voltage will be present at the ground contacts. Consequently, a typically low- voltage data communication line (e.g., 9-32 V dc according to the CAN SAE J1939 standard) can be integrated in the same part of the plug and socket. Only a thin isolation 10 barrier is needed between the ground contact and the data communication line, as opposed to the much bigger isolation barriers that are used to isolate the ground contact from the current-carrying contacts. For optimal conductivity and to enable the 15 electrical contacts to carry the high currents that are needed for ultra-fast high power charging, the wedge- shaped electrical contacts and the complementary electrical contacts have a preferred contact surface area of at least 0.02 m^2 for a 20 MW charger connector and at 20 least 0.04 m^2 for a 40 MW charger connector. For the same reasons, it is preferred to use high conductivity metals for the electrical contacts. In preferred embodiments, the electrical contacts comprise at least 90% and preferably at least 95% of silver. 25 Like the plug, the socket preferably comprises a connector casing, enclosing the at least three clamps. The connector casing may protect the electrical contacts against damage and dirt and the user against electric shocks. The connector casing may be flexible and comprise 30 a resilient material, such that the connector casing can bend and change shape while the clamp is brought from its closed to its opened configuration. The resiliency of the connector casing material can then help to bias the clamp back into its closed configuration. Alternatively, the connector casing is rigid and the clamps are configured to open and close within the rigid connector casing. Instead of, or in addition to, the use of a connector casing with resilient material for biasing the 5 clamps into their closed configuration, the casing and / or the clamps may comprise a spring for providing the required biasing force. In a special embodiment, the complementary electrical contacts comprise a plurality of perforations, 10 the connector and / or the clamps casing comprising an air supply network, arranged to supply pressured air to the perforations. During connection of the plug and socket, the perforations in the complementary electrical contacts allow any air or other gas supplied by the air supply 15 network to enter the space between the plug contacts and the socket contacts. The gas supply does not need to be continuous. By supplying a gas flow between the plug contacts and the socket contacts, just at the final moments of establishing the connection, any remaining dirt 20 or debris between the connector contacts is effectively blown out of the connector. While the perforations may be dispersed over the full surface of the complementary electrical contact, similar results may be achieved by arranging a smaller number of perforations over one or two 25 lines extending over a large portion of the full width of the electrical contact surface. In an embodiment of the invention, the socket further comprises a clip with two levers, configured to move the clamps to the open configuration when pressed 30 together. The clip and levers are provided to facilitate the opening of the clamps before the socket is connected to the plug. The levers may be operated by hand, by the user, or by some actuator that is controlled by an autonomous, or semi-autonomous connection and charging system. In a further advantageous embodiment, the bottom protrusion comprises a brush or scraper for cleaning the 5 wedge-shaped electrical contact while engaging the plug with the socket. In special embodiments, the bottom protrusion may comprise a roller for facilitating engaging the plug with the socket. This roller may run over the surface of the 10 wedge-shaped electrical contacts of the plug while the clamps are gradually opened and the connection between the plug and the socket is established. In this process, the roller may wipe or scrape some contamination from the surface of the plug contact. When the connection is fully 15 established, the roller may fully or partly reside in the clamping groove of the plug. According to other aspects of the invention a plug or a socket is provided for use in one of the plug and socket combinations described above. The plug or socket 20 may be provided at the distal end of a charging cable of a charging dispenser for electric vehicles. Various aspects of the invention will be discussed in more detail below, with reference to the drawings wherein one or more possible embodiments are shown. 25 Brief Description of the Drawings Figure 1 schematically illustrates an electric vehicle charging system that may benefit from the current invention. 30 Figure 2 shows a charging dispenser according to an embodiment of the invention. Figure 3 shows a perspective view of a plug according to an embodiment of the invention. Figure 4 shows a front view of the plug of Figure 3. Figure 5 shows a side view of a socket for use with the plug of Figures 3 and 4. Figure 6 shows a front view of the socket of Figure 5. 5 Figure 7 shows a front view of a different socket for use with the plug of Figures 3 and 4. Figure 8 shows a perspective view of a portion of a socket according to another embodiment of the invention. These drawings depict one or more implementations in 10 accordance with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements. Detailed Description of the Drawings 15 Figure 1 schematically illustrates an electric vehicle charging system that may benefit from the current invention. The charging system comprises a charging station or charging dispenser 10 that is coupled to the grid and provided for enabling the charging of the 20 batteries of electric vehicles, such as an electrified ship 12 and a mining truck 30. Alternatively, the charging dispenser 10 may be powered by a local or movable power source, such as a containerised electric power storage system, or a local wind turbine or solar power system. The 25 charging station 10 may comprise one or more charger plugs 25, connected to the charging dispenser 10 via a charger cable 22. The charger connectors 25, 35 can be inserted into the charging inlet of the electric vehicles 12, 30 for charging their batteries. The current invention 30 relates to a special plug or socket connector 25, 35 that makes it possible to charge the vehicle batteries at very high charging powers of up to (and above) 40 MW. With a suitable connector 25, 35 that allows for frequent and ultra-fast charging, the vehicle downtime for battery charging is minimised and many vehicles 12, 30 can be charged when needed using only a small number of charging dispensers. Figure 2 shows a charging dispenser 10 according to 5 an embodiment of the invention. The charging dispenser may comprise a graphical user interface 180 or allowing a user to start, stop, and otherwise control the charging of an electric vehicle 12, 30. In some embodiments, the charging dispenser 10 may be operated manually. In this embodiment, 10 the charging dispenser 10 is coupled to a robotic arm 170 carrying the charging connector 25, 35 and at least a portion of the charger cable 22. A control system provided in the robotic arm 170 and / or the charging dispenser 10 may control the robotic arm 170 to autonomously connect 15 the connector 25, 35 to the charging inlet of the vehicle 12, 30 to be charged. When the charging connector 25, 35 is fully connected to the charging inlet of the vehicle 12, 30, the charging dispenser 10 starts the charging of the vehicle 20 batteries. When the batteries are fully charged, or earlier if no full charge is needed, the robotic arm 170 is controlled to disconnect the connector 25, 35 from the vehicle 12, 30 and move it back into a position closer to the charging dispenser 10. 25 Figure 3 shows a perspective view of a plug 25 according to an embodiment of the invention. Front and side views of the same plug 25 are shown in Figures 4 and 5. The plug 25 may either be connected to the distal end of the charger cable 22 of the charging dispenser 10, or 30 installed in the charging inlet of the electrified vehicle 12, 30 to be charged. For practical reasons, it may be preferred that the plug 25 is provided at the vehicle 12, 30 and the socket (Figures 5 to 8) at the charger cable 22. With the socket 35 provided at the charger cable, only the charging dispenser needs an actuator for opening the clamps of the socket. When the socket 35 is provided in the vehicles 12, 30, each individual vehicle 12, 30 may need a separate actuator for opening the clamps. 5 Since the connector 25, 35 provided at the charger cable 22 will be used much more often than the connector 25, 35 provided at the vehicle 12, 30, a harder metal may be used for the charger-side electrical contacts than for the vehicle-side electrical contacts. This allows to 10 control wear of the electrical contacts 201, 202, 203, 301, 302, 303 in the most effective way possible. The plug 25 comprises at least three wedge-shaped electrical contacts 201, 202, 203 that may be provided on a common base platform 210. The electrical contacts 201, 15 202, 203 are separated by isolation barriers 230 and taper out from a narrow top 205 to a point of maximum width 206. ‘Narrow’ is herein defined relative to the maximum width 206 of the wedge. The ‘width’ of the wedge-shaped electrical contacts may refer to either a width 206 in the 20 front view as shown in Figure 4, or to a width 207 of the contacts 201, 202, 203 in a side view as shown in Figure 3. Each wedge-shaped contact 201, 202, 203 comprises a clamping groove 220 that is provided below the point of maximum width 206. 25 The wedge-shaped electrical contacts 201, 202, 203 of the plug 25 provides for a large surface contact area through which high currents can be drawn. This is especially important for the high power ultra-fast electrical vehicle charging for which the now presented 30 plug 25 and socket 35 combination may be used. Preferably, the plug 25 comprises a plug housing 240 that encloses the wedge-shaped electrical contacts 201, 202, 203 and has an opening 242 for receiving the socket, the narrow tops 205 of the wedge-shaped electrical contacts 201, 202, 203 facing the opening 242. The housing 240 protects both the plug contacts 201, 202, 203 from contamination by water or dirt from the plug environment, and the environment (including the user) from electrical 5 shocks and currents originating from the plug contacts 201, 202, 203. The opening 242 at the top of the plug housing 240 is needed to allow the socket 35 to approach the plug 25 and connect the clamps to the plug contacts 201, 202, 203. This opening 242 may be temporarily 10 shielded when the plug 25 and the socket 35 are disconnected, e.g. by spring biased hinged flaps. Preferably, as in Figure 3, the plug housing 240 is funnel-shaped. The funnel shape helps to align the socket 35 during the connection process. First, the wider opening 15 242 of the funnel makes it very easy to insert the socket 35 into the opening of the plug housing 240. Then, when the socket contacts move closer to plug contacts 201, 202, 203, the narrowing funnel 240 guides the socket contacts in the right direction. The added self-centering aspect of 20 the funnel-shaped housing 240 makes such a plug 25 even more suitable for use with an autonomous charging system. If the charging dispenser 10 charges the vehicle 12, 30 using direct current, a first contact 201 of the at least three contacts 201, 202, 203 is used as a positive 25 terminal 201, a second contact 202 is used as a ground contact 202, and a third contact 203 is used as a negative terminal 203. When two-phase alternating current is used for charging the vehicles 12, 30, the second electrical contact 202 may be used as the ground contact 202 too, 30 with the first and third contacts 201, 202 carrying the alternating current. Preferably the ground contact 202 is provided in between the two charged contacts 201, 203 for optimal spatial separation of the two current-carrying contacts 201, 202. When three-phase alternating current is used for charging the vehicles 12, 30, at least one more electrical contact will be provided for carrying the current of the third phase. Optionally, an additional, second ground 5 contact may be provided and positioned between the second and third current-carrying contacts. When using multiple ground contacts, each of the ground contacts may have a smaller width 207 than when just a single ground contact 202 is used. 10 In some embodiments, the plug 25 further comprises a data communication contact 204. The ground contact 202 and the data communication contact 204 may be configured to be clamped by the same one of the at least three clamps. While high power, large currents will run through the 15 current-carrying contacts 201, 203, virtually no voltage will be present at the ground contact 202. Consequently, a typically low-voltage data communication line 204 (e.g. 9- 32 V dc according to the CAN SAE J1939 standard) can be integrated in the same part of the plug 25. Only a thin 20 isolation barrier is needed between the ground contact 202 and the data communication line 204, as opposed to the much bigger isolation barriers 230 that are used to isolate the ground contact 202 from the current-carrying contacts 201, 203. 25 For optimal conductivity and to enable the electrical contacts 201, 203 to carry the high currents that are needed for ultra-fast high power charging, the wedge-shaped electrical contacts 201, 202, 203 have a preferred surface area of at least 0.02 m^2 for a 20 MW 30 charger connector and at least 0.04 m^2 for a 40 MW charger connector. To save costs and / or for a more compact design, the ground contact 202 may be made smaller than the current-carrying contacts 201, 203. It is further preferred to use high conductivity metals for the electrical contacts 201, 202, 203. In preferred embodiments, the electrical contacts 201, 202, 203 comprise at least 90% and preferably at least 95% of 5 silver. In addition to being a good bulk conductor, silver has the further advantage of having a great resistance against surface electrical conductivity degradation. In preferred embodiments, the The common base platform 210 and the isolation 10 barriers 230 are made of non-conductive materials. As shown in Figure 4, the isolation barriers 230 are preferably larger than the wedge-shaped electrical contacts 200, 202, 203 when seen from the front or rear of the plug 25. By extending well beyond the complete outer 15 edges of the wedge-shaped electrical contacts 201, 202, 203, the risk of electrical currents jumping over the barrier 230 to a neighbouring contact 201, 202, 203 is significantly reduced. This risk can be further reduced by providing grooves in the isolation barriers 230 to further 20 increase the creep distance (i.e., the shortest distance along the surface of a solid insulating material between two conductive parts). Polymer surface treatment may be used, e.g. with polytetrafluoroethylene, for the isolation barriers 230 to repel water and thereby further minimise 25 the risk of currents jumping over the isolation barriers 230. Figure 5 shows a side view of a socket 35 for use with the plug 25 of Figures 3 and 4. Figure 6 shows a front view of the socket 35 of Figure 5. The socket 35 30 comprises at least three clamps 311, 312, 313 having an open and a closed configuration and being biased to the closed configuration. The number of clamps 311, 312, 313 in the socket 35 may correspond to the number of electrical contacts 201, 202, 203 in the plug 25. However, as explained above, a single clamp 312 may, e.g., cooperate with a ground contact 202 and one or more data communication contacts 204. An inner surface of each clamp comprises a complementary electrical contact 301, 302, 5 303, shaped to receive and contact a respective one of the at least three wedge-shaped electrical contacts 201, 202, 203 of the plug 25 when in the open configuration. The clamps 311, 312, 313 further comprise a bottom protrusion 360 (see Figure 6), configured to engage with the clamping 10 groove 220 of the respective wedge-shaped electrical contact 201. Preferably, the clamping groove 220 comprises a curved edge that is configured to effectively pull in the bottom protrusion 360 of the clamp 311, 312, 313 to drag the clamp 311, 312, 313 downwards during the final 15 moments of establishing the connection between the plug 25 and the socket 35. The wedge shape of the plug contacts 201, 202, 203 helps the clamps 311, 312, 313 to automatically and accurately align with the plug contacts 201, 202, 203 20 while being pushed open by the widening body shape of thereof. The self-centering function of the wedge-shaped electrical contacts 210, 202, 203 make this plug and socket combination very suitable for autonomous charging systems, wherein a robotic 170 arm may need to connect the 25 connector plug 25 or socket 35 to a charging inlet of which the exact location may be unknown when the connection process is initiated. On top of the self-centering benefits of the plug and socket combination according to the invention, the 30 wedge shape of the plug contacts 201, 202, 203, together with the clamp’s biasing force into the closed configuration, causes the clamp’s bottom protrusion 360 to automatically clean the contact surface of the plug contacts 201, 202, 203 while the connection between the plug 25 and the socket 35 is made. This self-cleaning effect is further enhanced by the full electrical contacts of the plug 201, 202, and the socket 35 having a short gliding contact in the final moments of connection, just 5 when the bottom protrusion 360 of the socket slips into the clamping groove 220. With every connection or disconnection of the plug and socket combination, this short cleaning action by the two sliding electrical contact surfaces efficiently removes any oxidation that 10 may otherwise build up on the contact surfaces. As a result, the electrical contacts 201, 202, 203, 301, 302, 303 are kept clean automatically just by using them, even when used in dirty or humid environments. In some embodiments, the bottom protrusion 360 15 comprises a brush or scraper for cleaning the surface of the wedge-shaped electrical contact 201, 202, 203 while engaging the plug 25 with the socket 35. Like the plug 25, the socket 35 preferably comprises a connector casing 340 enclosing the at least three clamps 20 311, 312, 313. The connector casing 340 may protect the electrical contacts 301, 302, 303 against damage and dirt and the user against electric shocks. The connector casing 340 may be flexible and comprise a resilient material, such that the connector casing 340 can bend and change 25 shape while the clamp 311, 312, 313 is brought from its closed to its opened configuration. The resiliency of the connector casing material can then help to bias the clamp 311, 312, 313 back into its closed configuration. Alternatively, the connector casing 340 is rigid and the 30 clamps 311, 312, 313 are configured to open and close within the rigid connector casing 340. Instead of, or in addition to, the use of a connector casing 340 with resilient material for biasing the clamps 311, 312, 313 into their closed configuration, the casing 340 and / or the clamps 311, 312, 313 may comprise a spring for providing the required biasing force. The sockets 35 shown in the drawings further 5 comprise a clip 320 with two levers, configured to move the clamps 311, 312, 313 to the open configuration when pressed together. The clip 320 is mounted to an external surface of one of the clamps 311 via a clip mount 325. The clip 320 and its levers are provided to facilitate the 10 opening of the clamps 311, 312, 313 before the socket 35 is connected to the plug 25. The levers may be operated by hand, by the user, or by some actuator that is controlled by an autonomous, or semi-autonomous connection and charging system. The socket shown in the current Figures 15 comprises just a single clip 320 which is provided with the first clamp 311. All clamps 311, 312, 313 may be mechanically coupled such that they are jointly opened and closed by the operation of just the single clip 320. Other sockets 35 may have multiple clips 320, for example one 20 for each clamp 311, 312, 313. When multiple clips 320 are used, they may either be jointly operated by a single actuator, or a separate actuator may be provided for opening and closing each clamp 311, 312, 313. Figure 7 shows a front view of a different socket 35 25 for use with the plug 25 of Figures 3 and 4. In this embodiment, the complementary electrical contacts 301, 302, 303 of the socket comprise a plurality of perforations, the connector casing 340 and / or the clamps 311, 312, 313 comprise an air supply network 350, arranged 30 to supply pressured air (represented by the arrows in Figure 7) to the perforations. During connection of the plug 25 and socket 35, the perforations in the complementary electrical contacts 301, 302, 303 allow any air or other gas supplied by the air supply network to enter the space between the plug contacts 201, 202, 203 and the socket contacts 301, 302, 303. The gas supply does not need to be continuous. By supplying a gas flow between the plug contacts 201, 202, 203 and the socket contacts 5 301, 302, 303, just at the final moments of establishing the connection, any remaining dirt or debris between the connector contacts 201, 202, 203, 301, 302, 303 is effectively blown out of the connector. While the perforations may be dispersed over the full surface of the 10 complementary electrical contact 301, 302, 303, similar results may be achieved by arranging a smaller number of perforations over one or two lines extending over a large portion of the full width of the electrical contact surface. 15 In the embodiment shown in Figure 7, the bottom protrusion 360 comprises a roller 370 for facilitating engaging the plug 25 with the socket 35. This roller 370 may run over the surface of the wedge-shaped electrical contacts 201, 202, 203 of the plug 25 while the clamps 20 311, 312, 313 are gradually opened and the connection between the plug 25 and the socket 35 is established. In this process, the roller 370 may wipe or scrape some contamination from the surface of the plug contact 201, 202, 203. When the connection is fully established, the 25 roller 360 may fully or partly reside in the clamping groove 220 of the plug 25. Finally, Figure 8 shows a perspective view of a portion of a socket 35 according to another embodiment of the invention. The socket of Figure 8 does have the air 30 supply network 350 of the embodiment of Figure 7, but not its roller 370. In this Figure, the clamp 311 is shown to be in its closed configuration. It can be opened by operating the clip 320. When opened far enough, the electrical contacts 301, 302, 303 at the inner surfaces of the clamps 311, 312, 313 are placed over the narrow tops 205 of the corresponding wedge-shaped contacts 201, 202, 203 of the plug 25 of, e.g., Figure 3. The clamps 311, 312, 313 are then further opened by operation of the clip 5 320 and / or by pushing the clamps 311, 312, 313, over the widening wedge-shaped electrical contacts 201, 202, 203 of the plug 25. When the bottom protrusions 360 of the clamps 311, 312, 313 pass the point of maximum width 206 of the wedge-shaped contacts 201, 202, 203, the snap into the 10 clamping grooves 220 and the plug 25 and socket 35 are fully connected. While many possible variations of the plug and socket combination according to the invention have been described above, it will be clear to the skilled person 15 that additional variations and modifications can be made without departing from the scope of the invention as claimed in the appended claims.

Claims

SP2953 - 19 - C L A I M S 1. A plug and socket combination for connecting a charging cable (22) to a charging inlet of an electric vehicle (12, 30), the plug and socket combination comprising a plug (25) and a socket (35), wherein: 5 - the plug (25) comprises at least three wedge-shaped electrical contacts (201, 202, 203) separated by isolation barriers (230) and tapering out from a narrow top (205) to a point of maximum width (206), a clamping groove (220) being provided below the point of maximum width (206); 10 - the socket (35) comprises at least three clamps (311, 312, 313) having an open and a closed configuration and being biased to the closed configuration, an inner surface of the clamps (311, 312, 313) comprising a complementary electrical contact (301, 302, 303), shaped to receive and15 contact a respective one of the at least three wedge- shaped electrical contacts (201, 202, 203) of the plug (25) when in the open configuration, the clamps (311, 312, 313) further comprising a bottom protrusion (360), configured to engage with the clamping groove (220) of the 20 respective wedge-shaped electrical contact (201, 202, 203).

2. A plug and socket combination as claimed in Claim 1, wherein the plug (25) comprises a plug housing (240), 25 enclosing the wedge-shaped electrical contacts (201, 202, 203) and having an opening (242) for receiving the socket (35), the narrow tops (205) of the wedge-shaped electrical contacts (201, 202, 203) facing the opening (242). 30 3. A plug and socket combination as claimed in Claim 2, wherein the plug housing (240) is funnel-shaped.

4. A plug and socket combination as claimed in any preceding Claim, wherein at least one of the wedge-shaped electrical contacts (201, 202, 203) is a ground contact 5 (202), the plug (25) further comprising a data communication contact (204), wherein the ground contact (202) and the data communication contact (204) are configured to be clamped by the same one of the at least three clamps (311, 312, 313). 10 5. A plug and socket combination as claimed in any preceding Claim, wherein the wedge-shaped electrical contacts (201, 202, 203) and the complementary electrical contacts (301, 302, 303) have a contact surface area of at 15 least 0.02 m^2, preferably at least 0.04 m^2.

6. A plug and socket combination as claimed in any preceding Claim, wherein the wedge-shaped electrical contacts (201, 202, 203) and / or the complementary 20 electrical contacts (301, 302, 303) comprise at least 90%, preferably at least 95%, of silver.

7. A plug and socket combination as claimed in any preceding Claim, wherein the socket (35) further comprises 25 a connector casing (340) enclosing the at least three clamps (311, 312, 313).

8. A plug and socket combination as claimed in Claim 7, wherein the connector casing (340) is flexible and 30 comprises a resilient material.

9. A plug and socket combination as claimed in any preceding Claim, wherein the complementary electrical contacts (301, 302, 303) comprise a plurality ofperforations, the connector casing (340) and / or the clamps (311, 312, 313) comprising an air supply network (350), arranged to supply pressured air to the perforations. 5 10. A plug and socket combination as claimed in any preceding Claim, wherein the socket (35) further comprises a clip (320) with two levers, configured to move the clamps (311, 312, 313) to the open configuration when pressed together. 10 11. A plug and socket combination as claimed in any preceding Claim, wherein the bottom protrusion (360) comprises a brush or scraper for cleaning the wedge-shaped electrical contact (201, 202, 203) while engaging the plug 15 (25) with the socket (35).

12. A plug and socket combination as claimed in any preceding Claim, wherein the bottom protrusion (360) comprises a roller (370) for facilitating engaging the 20 plug (25) with the socket (35).

13. A plug (25) for use in the plug and socket combination of any of the preceding Claims. 25 14. A socket (35) for use in the plug and socket combination of any of Claims 1 to 12.

15. A charging dispenser (10) for electric vehicles (12, 30) comprising a plug (25) as claimed in Claim 13 or a 30 socket (35) as claimed in Claim 14.

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