An electric charging system for an electric vehicle
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- KEMPOWER OYJ
- Filing Date
- 2024-12-05
- Publication Date
- 2026-06-11
Smart Images
Figure EP2024084800_11062026_PF_FP_ABST
Abstract
Description
[0001] An electric charging system
[0002] Field
[0003] The invention relates generally to charging of electric vehicles. More particularly, the invention relates to an electric charging system for charging an electric vehicle such as e.g. an electric truck, an electric van, or an electric car. Furthermore, the invention relates to a truck terminal for loading and unloading goods to and from electric trucks and for charging the electric trucks.
[0004] Background
[0005] A typical electric charging system for charging an electric vehicle comprises an alternating or direct voltage energy supply and an electric conductor arrangement for transferring electric energy from the energy supply to a charging plug connectable to a charging socket of the electric vehicle. Publication US20120013300A1 describes a charging system for reaching and charging electric vehicles parked in a pair of adjacent rows of side-by-side parking spaces. The charging system described in publication US20120013300A1 comprises a support rail, a pair of trolleys, an electric vehicle charger, and an apparatus for electrically connecting the electric vehicle charger to a power source without impinging upon movement of the pair of trolleys along the support rail. The support rail mounts overhead of, and traverses, the pair of adjacent rows of side-by-side parking spaces. The pair of trolleys are movably mounted along the support rail and reach the electric vehicles parked in the pair of adjacent rows of the side-by-side parking spaces. The electric vehicle charger is mounted on, and moves with, the pair of trolleys to charge the electric vehicles parked in the pair of adjacent rows of the side-by-side parking spaces. The charging system comprises rigid voltage rails which are horizontal, parallel with each other and with the support rail, mechanically supported by insulated suspenders, and electrically connected to the power source. The electric vehicle charger comprises collector shoes configured to slide along the voltage rails and to form galvanic contacts with the voltage rails. The electric vehicle charger comprises a charger circuitry for converting voltage received by the collector shoes into a form suitable for charging an electric vehicle and a charging cable whose end is provided with a charging plug connectable to a charging socket of the electric vehicle.
[0006] An inherent challenge related to charging systems of the kind described in publication US20120013300A1 is that the overhead support rails need vertical beams and / or girder bridges and / or other support structures configured to sustain the overhead support rails. For example, in conjunction with a large truck terminal having many loading docks, it may be challenging to arrange the above-mentioned support structures so that the support structures do not excessively disturb truck traffic in the truck terminal. Another challenge related to charging systems of the kind described in publication US20120013300A1 is that the above-mentioned collector shoes need to be, on one hand, slidable along the voltage rails and, on the other hand, capable of forming reliable galvanic contacts with the voltage rails. In cases where a charging system is designed for high power vehicles such as electric trucks, electric currents through collector shoes or other corresponding contact elements can be as high as e.g. from 500 to 1500 amperes. Thus, even a small contract resistance may cause high local temperatures, and the contact elements and the voltage rails may even weld to each other. A known approach to reduce electric current through a slidable contact is to increase voltage, as is the case with e.g. electric trains where voltage of an overhead conductor can be e.g. 25 kV. It would be, however, challenging to use high voltage, such as 25 kV, in voltage rails of a charging system for electric vehicles.
[0007] Summary
[0008] The following presents a simplified summary to provide basic understanding of some embodiments of the invention. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments.
[0009] In this document, the word “geometric” when used as a prefix means a geometric concept that is not necessarily a part of any physical object. The geometric concept can be for example a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity that is zero, one, two, or three dimensional.
[0010] In accordance with the invention, there is provided a new electric charging system for charging an electric vehicle such as e.g. an electric truck, an electric van, or an electric car. In this document, the term “electric vehicle” covers not only full-electric vehicles but also pluggable hybrid vehicles which comprise both one or more electric motors and a combustion motor.
[0011] An electric charging system according to the invention comprises:
[0012] - a direct voltage power supply,
[0013] - direct voltage rails connected to the direct voltage power supply and thus having a direct voltage therebetween and being i) bars of rigid and electrically conductive material and ii) parallel with each other, and
[0014] - a supply sledge moveable along the direct voltage rails.
[0015] The supply sledge comprises contact elements configured to form galvanic contacts with the direct voltage rails and electric conductors having lower parts galvanically connected to the contact elements and upper parts galvanically connected to a first end of a charging cable, wherein the first end of the charging cable is higher in the vertical direction than the direct voltage rails and a second end of the charging cable is provided with a charging plug connectable to a charging socket of the electric vehicle. Thus, the electric energy is supplied from below from the direct voltage rails to the first end of the charging cable.
[0016] In an electric charging system according to an advantageous and exemplifying embodiment, the above-mentioned direct voltage rails are within an elongated gutter opening upwards and having its longitudinal direction parallel with the longitudinal direction of the direct voltage rails. The elongated gutter can be advantageously so low in the vertical direction, or the elongated gutter can be at least partly buried in the ground so that electric vehicles can drive over the elongated gutter. Thus, there is no need for vertical beams and / or girder bridges and / or other support structures to sustain overhead voltage rails or the like and, on the other hand, the direct voltage rails do not disturb traffic.
[0017] The above-mentioned supply sledge further comprises a force-control system configured to change, responsive to a control signal, contact forces between the contact elements and the direct voltage rails. Therefore, in conjunction with the above-described electric charging system, it is possible to utilize the fact that large electric currents via the contact elements are not needed when the supply sledge is moving along the direct voltage rails but only when the supply sledge is at standstill.
[0018] An electric charging system according to an exemplifying and non-limiting embodiment may comprise for example a control system that is configured to carry out a loading-handshake after connecting the charging plug to the charging socket of the electric vehicle and to form the above-mentioned control signal so that the contact forces between the contact elements and the direct voltage rails are increased in response to the loading-handshake and decreased after charging the electric vehicle. The loading-handshake can be according to for example any suitable known charging protocol. It is also possible that the control signal is generated manually via a user interface, e.g. when connecting the charging plug to a charging socket of an electric vehicle. In general, the control signal to control the contact forces between the contact elements and the direct voltage rails can be generated in many ways. In addition to the above-mentioned examples, the contact forces can be increased for example in response to a situation in which the supply sledge is at a predetermined position with respect to an electric vehicle, in response to a situation in which the supply sledge is within a predetermined distance from a charging socket of an electric vehicle, in response to a situation in which the supply sledge has been at a standstill for a predetermined time, and / or in response to a situation in which the charging plug has been removed from its holder. Thus, the invention is not limited to any specific ways to generate the control signal to control the contact forces between the contact elements and the direct voltage rails.
[0019] In accordance with the invention, there is also provided a new truck terminal for loading and unloading goods to and from electric trucks and for charging the electric trucks. A truck terminal according to the invention comprises a direct voltage power supply system and one or more loading docks each being suitable for receiving a back of an electric truck for loading and unloading goods through the back of the electric truck. Each of the one or more loading docks comprises an electric charging system according to the invention so that the direct voltage rails of the electric charging system are perpendicular to the loading dock and parallel with a longitudinal direction of the electric truck when the electric truck is at the loading dock, and the direct voltage power supply system of the truck terminal constitutes the direct voltage power supply of the electric charging system of each of the one or more loading docks.
[0020] Exemplifying and non-limiting embodiments are described in accompanied dependent claims.
[0021] Various exemplifying and non-limiting embodiments both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying and nonlimiting embodiments when read in conjunction with the accompanying drawings.
[0022] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of un-recited features.
[0023] The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated.
[0024] Furthermore, it is to be understood that the use of “a” or “an”, i.e. a singular form, throughout this document does not exclude a plurality.
[0025] Brief description of figures
[0026] Exemplifying and non-limiting embodiments and their advantages are explained in greater detail below in the sense of examples and with reference to the accompanying drawings, in which: figures 1 a and 1 b illustrate an electric charging system according to an exemplifying and non-limiting embodiment, figure 2 illustrates a detail of an electric charging system according to an exemplifying and non-limiting embodiment, figure 3 illustrates a truck terminal comprising electric charging systems according to an exemplifying and non-limiting embodiment, and figures 4 illustrates a truck terminal comprising electric charging systems according to an exemplifying and non-limiting embodiment.
[0027] Description of exemplifying and non-limiting embodiments
[0028] The specific examples provided in the description below should not be construed as limiting the scope and / or the applicability of the invention. Lists and groups of examples provided in the description are not exhaustive unless otherwise explicitly stated.
[0029] Figure 1 a shows a schematic side view of an electric charging system according to an exemplifying and non-limiting embodiment. A part of the electric charging system is shown as a section view where the geometric section plane is parallel with the yz- plane of a coordinate system 199. The electric charging system comprises a direct voltage power supply 101 that may comprise for example an alternating current - direct current “AC-DC” converter connected to an AC power grid. The AC power grid is not shown in figure 1 a. The electric charging system comprises direct voltage rails which are parallel with each other and connected to the direct voltage power supply 101 and thus have a direct voltage therebetween. The direct voltage rails are bars of rigid and electrically conductive material, e.g. copper. In figure 1 a, one of the direct voltage rails is denoted with a reference 102 and the longitudinal direction of the direct voltage rails is parallel with the y-axis of the coordinate system 199. In this exemplifying electric charging system, the direct voltage rails are below the ground level, but it is also possible that the direct voltage rails are installed on a platform that is on the ground and thus the direct voltage rails are above the ground level. The exemplifying electric charging system illustrated in figure 1 a comprises a support beam 121 parallel with the direct voltage rails. The direct voltage rails are mechanically attached to the support beam 121 with the aid of electric insulator elements. It is also possible that electric charging system according to an exemplifying and non-limiting embodiment does not comprise a support beam of the kind mentioned above but the direct voltage rails are supported with electrically insulating suspension elements to e.g. concrete-made structures resting on the ground.
[0030] The electric charging system comprises a supply sledge 104 that is moveable along the direct voltage rails. Figure 1 b shows a schematic section view of a part of the supply sledge 104. The section has been taken along a geometric line A-A shown in figure 1 a, and the geometric section plane is parallel with the xz-plane of the coordinate system 199. In figure 1 b, the cross-sections of the direct voltage rails are denoted with references 102 and 103, and the electric insulator elements mechanically supporting the direct voltage rails 102 and 103 with respect to the support beam 121 are denoted with references 122 and 123. The support beam 121 is between the direct voltage rails 102 and 103 so that each geometric line between the direct voltage rails intersects the support beam 121. The support beam 121 is advantageously connected to the ground potential as it is schematically shown in figures 1 a and 1 b. Thus, there is no direct route for a short circuit arc between the direct voltage rails 102 and 103. In this exemplifying case, the support beam 121 is an i-profile beam as shown in figure 1 b. A middle part 127 of the i-profile beam is vertical when seen along a longitudinal direction of the i-profile beam i.e. along the y-axis of the coordinate system 199. The middle part 127 of the i-profile beam is between the direct voltage rails 102 and 103, and an upper part 128 of the i-profile beam covers the direct voltage rails 102 and 103 when seen from above. In this exemplifying case, the direct voltage rails 102 and 103 are horizontally parallel with each other but different arrangements are possible, too. For example, one direct voltage rail can be vertically or obliquely above another direct voltage rail.
[0031] In the exemplifying an electric charging system illustrated in figures 1a and 1 b, the direct voltage rails 102 and 103 and the support beam 121 are within an elongated gutter 114 that opens upwards and has a longitudinal direction parallel with the longitudinal direction of the direct voltage rails 102 and 103 and the support beam 121 , i.e. the longitudinal direction of the elongated gutter 114 is parallel with the y- axis of the coordinate system 199. The elongated gutter 114 can be made of, for example, concrete. In this exemplifying electric charging system, the elongated gutter 114 is embedded in the ground so that upper rims of the elongated gutter 114 are in flush with the ground level. It is however also possible that an elongated gutter containing direct voltage rails is only partially embedded in the ground or the elongated gutter is on the ground. An advantage of an arrangement where an elongated gutter of the kind mentioned above is fully or at least sufficiently embedded in the ground is that vehicles can move over the elongated gutter and thus disturbing effect caused by the electric charging system on leaving and arriving vehicles can be minimized. In figures 1a and 1 b, the ground is denoted with a reference 115.
[0032] In the exemplifying electric charging system illustrated in figures 1 a and 1 b, the upper surface of the support beam 121 is in flush with the upper rims of the elongated gutter 114 and thereby the upper surface of the support beam 121 is in flush with the ground level. Furthermore, the support beam 121 is on an elevation 126 on the bottom of the elongated gutter 114 so that the lower surface of the support beam 121 is higher in the vertical direction, i.e. in the z-direction of the coordinate system 199, than a part of the upper surface of the bottom of the elongated gutter 114. This reduces the risk that possible water in the elongated gutter 114 would get in contact with the support beam 121. The electric charging system comprises advantageously an underground drain 116 being lower in the vertical direction, i.e. in the z-direction of the coordinate system 199, than the bottom of the elongated gutter 114. The bottom of the elongated gutter 114 comprises advantageously apertures to allow water to leave the elongated gutter. In figures 1 a and 1 b, four of the apertures are denoted with references 117, 118, 119, and 120. The underground drain 1 16 can be e.g. a perforated pipe, and there can be water permeable gravel surrounding the perforated pipe.
[0033] The supply sledge 104 comprises contact elements 105 and 106 configured to form galvanic contacts with the direct voltage rails 102 and 103, respectively. The supply sledge 104 comprises a force-control system configured to change, responsive to a control signal 113, contact forces between the contact elements 105 and 106 and the direct voltage rails 102 and 103. In this exemplifying case, the force-control system comprises controllable force-generating devices configured to pull the contact elements 105 and 106 against the direct voltage rails 102 and 103 to provide contact forces between the contact elements 105 and 106 and the direct voltage rails 102 and 103. In this exemplifying case, the force-generating devices are electromagnets 129 and 130 but it is also possible to use e.g. pneumatic, hydraulic, or mechanical force-generating devices. The electromagnets 129 and 130 are configured to act against the gravity force when pulling the contact elements 105 and 106 against the direct voltage rails 102 and 103. Thus, the gravity force detaches the contact elements 105 and 106 from the direct voltage rails 102 and 103 in absence of electric currents in the electromagnets 129 and 130, for example in a fault situation. Furthermore, the force-control system can be provided with springs 131 and 132 configured to detach the contact elements 105 and 106 from the direct voltage rails 102 and 103 in absence of electric currents in the electromagnets 129 and 130. In the exemplifying case illustrated in figure 1 b, the supply sledge 104 comprises a controller 136 that is configured to receive the control signal 113 and to control the electromagnets 129 and 130 in accordance with the received control signal 113.
[0034] The electric charging system illustrated in figures 1 a and 1 b may comprise for example a control system 134 that is configured to control the direct voltage supply 101 and to carry out a loading-handshake after a charging plug 111 has been connected to a charging socket 112 of an electric vehicle 153. The control system 134 can be outside the supply sledge 104 as shown in figure 1 a, or a part of the control system 134 for controlling the direct voltage supply 101 can be outside the supply sledge 104 and another part of the control system for controlling the loadinghandshake can be a part of the supply sledge 104, or the control system 134 can be implemented in some other way.
[0035] In an electric charging system according to an exemplifying and non-limiting embodiment, the control system 134 is configured to form the above-mentioned control signal 113 so that the contact forces between the contact elements 105 and 106 and the direct voltage rails 102 and 103 are increased in response to the loading-handshake and decreased after charging the electric vehicle 153. The loading-handshake can be according to for example any suitable known charging protocol. It is however also possible that the control signal 113 is generated manually via a user interface in conjunction when connecting the charging plug 111 to the charging socket 112 of the electric vehicle. In general, the control signal 113 to control the contact forces between the contact elements 105 and 106 and the direct voltage rails 102 and 103 can be generated in many ways. In addition to the above-mentioned examples, the contact forces can be increased for example in response to a situation in which the supply sledge 104 is at a predetermined position with respect to the electric vehicle 153, in response to a situation in which the supply sledge 104 is within a predetermined distance from the charging socket 112 of the electric vehicle 153, in response to a situation in which the supply sledge 104 has been at a standstill for a predetermined time, and / or in response to a situation in which the charging plug 111 has been removed from its holder. Thus, it is to be noted that embodiments of the invention are not limited to any specific ways to generate the control signal 113 to control the contact forces between the contact elements 105 and 106 and the direct voltage rails 102 and 103.
[0036] The supply sledge 104 comprises electric conductors 107 and 108 which are galvanically connected to the above-mentioned contact elements 105 and 106 and to a first end 110 of a flexible charging cable 109 whose second end is provided with the charging plug 111. In figure 1 b, only a part of the charging cable 109 is shown. In this exemplifying embodiment, the electric conductors 107 and 108 are bars of rigid and electrically conductive material, e.g. copper. The lower parts of the electric conductors 107 and 108 are galvanically connected to the contact elements 105 and 106, and the upper parts of the electric conductors 107 and 108 are galvanically connected to the first end 110 of the charging cable 109. The first end 110 of the charging cable 109 is higher in the vertical direction than the direct voltage rails 102 and 103. Thus, the electric energy is supplied from below from the direct voltage rails 102 and 103 to the first end 110 of the charging cable 109. It is straightforward to arrange cross-sectional areas of the electric conductors 107 and 108 which are bars of electrically conductive material to be greater than corresponding cross- sectional areas of electric conductors of the flexible charging cable 109. Thus, power losses per meter can be significantly smaller in the electric conductors 107 and 108 than in the charging cable 109. This is significant especially when charging power is on megawatt-level. As shown in figure 1 a, the supply sledge 104 comprises a vertical elongated portion 158. The electric conductors 107 and 108 which are bars of electrically conductive material can be arranged to reach higher inside the vertical elongated portion 158 than what is shown in figure 1 b to make the charging cable 109 shorter.
[0037] As shown in figure 1 b, there are gaps between the upper rims of the elongated gutter 114 and the upper part 128 of the support beam 121 on both sides of the support beam 121. The gaps are elongated in the y-direction of the coordinate system 199. The electric conductor 107 is configured to extend to the contact element 105 via a first one of the elongated gaps and the electric conductor 108 is configured to extend to the contact element 106 via a second one of the elongated gaps. Each of the elongated gaps is provided with elongated and flexible lip elements attached to edges of the elongated gap, being against each other to close the elongated gap, and being bent by the supply sledge 104 to allow the electric conductors 107 and 108 to extend via the elongated gaps to the contact elements 105 and 106. In figure 1 b, two of the flexible lip elements are denoted with references 124 and 125. The flexible lip elements reduce access of water and dirt into the elongated gutter 114. The flexible lip elements can be made of for example rubber or fiber reinforced rubber.
[0038] Charging power of an electric charging system according to an exemplifying and non-limiting embodiment can be for example at least 200 kW, or at least 400 kW, or at least 600 kW, or at least 800 kW, or at least 1 MW, or at least 1 .2 MW, or higher. Dimensions of the cross-section of each of the electric conductors 107 and 108 can be e.g. 10 mm x 100 mm or 10 mm x 80 mm so that the longer dimension is parallel with the y-axis of the coordinate system 199 and the shorter dimension is parallel with the x-axis of the coordinate system 199. In an exemplifying case where the cross-sectional dimensions are 10 mm x 100 mm and the material of the electric conductors 107 and 108 is copper having resistivity 1.68 xw8fim, the resistance per meter of the electric conductors 107 and 108 is 1 .68 xW5Q / m. If the current is e.g. 1500 A, the power loss per meter is 37.8 W / m. In stagnant air, the cooling efficiency is about 10W / °C / m2Thus, the temperature rise is about 3.78 °Cm2 / (2 x 0.1 m x 1 m + 2 x 0.01 m x 1 m) = 172°C. In a typical flexible cable, the power loss per meter can be from 2 to 3 kW which is significantly higher than the above- mentioned 37.8 W / m. The exemplifying supply sledge 104 illustrated in figure 1 b comprises cooling ducts for circulating cooling fluid to cool the charging cable 109, the charging plug 111 , and the electric conductors 107 and 108. In figure 1 b, the cooling ducts are depicted schematically with dashed lines 138. The cooling fluid can be e.g. transformer oil. In cases where electric conductors having voltage are insulated from the cooling fluid and thus the cooling fluid does not need to be electrically insulating, the cooling fluid can be e.g. water-glycol mixture. In the exemplifying case shown in figure 1 b, the supply sledge 104 comprises a circulation pump 140 and a heat-exchanger 139 configured to transfer heat from the cooling fluid to the ambient air. It is also possible that the supply sledge 104 is connected with a flexible hose to an external system for circulating cooling fluid. In the exemplifying case illustrated in figure 1 b, the direct voltage rails 102 and 103 have longitudinal cooling channels 155 and 156. The direct voltage rails 102 and 103 can be connected with electrically insulating pipes to a cooling system for circulating cooling fluid through the direct voltage rails 102 and 103.
[0039] An electric charging system according to an exemplifying and non-limiting embodiment comprises a sensor system configured to produce sensor data indicative of a position of the front of an electric vehicle when the electric vehicle is on a charging area of the electric charging system. The sensor system may comprise for example a laser sensor, a radio sensor, an ultrasonic sensor, a machine vision system, and / or one or more inductor loops in / on a ground of the charging area occupied by an electric vehicle to be charged. In figure 1 a, a device that can be e.g. a laser sensor, a radio sensor, an ultrasonic sensor, or a camera of a machine vision system is denoted with a reference 137.
[0040] In an electric charging system according to an exemplifying and non-limiting embodiment, a sensor of the kind mentioned above is installed to a terminal building, on a wall facing towards docks or on the roof, for example. Also, a lighting pole or such a high enough structure with a complete view to the charging area or areas would be a suitable place for the sensor. This provides a clear view over an entire area having the charging area or areas of the electric charging system, e.g. docking areas of a truck terminal. If the sensor is selected to be omnidirectional, e.g. a fisheye camera or a lidar, one sensor could monitor a plurality of charging areas as well as the moving supply sledge. Also, a camera or a lidar with sufficient field of view to cover the entire area having the charging area or areas could be utilized. In image processing, the field of view data could be partitioned in such a way that each partition would cover one charging area with corresponding supply sledge. With such data, the position of an electric vehicle, the supply sledge, and possible other objects could be recognized. If for example there were a person or significant size debris, e.g. boxes, crates, stones, on the way of the supply sledge, the above- mentioned data could be used to stop the supply sledge movement to avoid collision. The sensor can have both camera and lidar properties, either combined as one sensor or, alternatively, two different sensors, as this would enable both image-based detection, e.g. a foreign object, make and / or model of the electric vehicle, a license plate, a printed text, etc., and also the form of the objects, e.g. charging socket or another recognizable part of the electric vehicle for positioning of the supply sledge.
[0041] In an electric charging system according to an exemplifying and non-limiting embodiment, a sensor of the kind mentioned above is installed on the sledge. In this embodiment, each sledge would have their own sensor for detecting the position of the electric vehicle and possibly the location of the charging socket, and for detecting foreign objects for collision prevention. Sensor based collision detection could even be utilized if the supply sledge is manually driven for safety reasons. As the supply sledge is movable in two different directions, either an omnidirectional sensor, or two sensors with opposing field of view directions can be utilized.
[0042] The exemplifying supply sledge 104 illustrated in figure 1 b comprises a servomotor 135 configured to drive wheels 157 to move the supply sledge 104 along the direct voltage rails 103 and 103. The wheels 157 can be coated with rubber or other suitable material which provides sufficient friction. Instead of the wheels 157 it is also possible to use toothed wheels which mesh with toothed bars attached on top of the support beam 121. It is also possible that a servomotor for moving the supply sledge is located at an end of the support beam 121 and the supply sledge 104 is moved by a wire rope or chain arrangement driven by the servomotor. In the exemplifying case illustrated in figure 1 b, the wheels 157 support the supply sledge 104 vertically with respect to the support beam 121. The supply sledge 104 is horizontally supported by guide wheels 159 with respect to the support beam 121. Furthermore, there can be guide wheels under the upper part 128 of the support beam 121 as shown in figure 1 b to prevent tilting of the supply sledge 104. In the exemplifying case illustrated in figure 1 b, the controller 136 is configured to control the servomotor 135 to move the supply sledge 104 to a position determined by the sensor data indicative of a position of the front of an electric vehicle. The determined position can be e.g. 1 -3 meters backwards from the position of the front of the electric vehicle.
[0043] To carry out the above-mentioned loading-handshake and possible other phases of a charging protocol, there is typically a need for information transfer from the charging plug 111 to the control system 134. The exemplifying electric charging system illustrated in figure 1 a comprises a flexible data transfer cable 160 between the control system 134 and the supply sledge 104 and another data transfer cable between the supply sledge 104 and the charging plug 111. The flexible data transfer cable 160 is wound to or unwound from a spool 141 when the supply sledge 104 moves towards or away from the control system 134. The data transfer cable between the supply sledge 104 and the charging plug 111 is depicted schematically with a dash-and-dot line in figure 1 b. It is also possible that the information transfer is implemented with e.g. a short-range radio link.
[0044] In addition to the above-mentioned information transfer, there can be a need for electric power within the supply sledge 104 because the supply sledge 104 may comprise one or more devices needing electricity, such as the circulation pump for circulating cooling fluid, the servomotor 135 for moving the supply sledge, and / or one or more sensors. The above-mentioned flexible data transfer cable 160 can be a combined data transfer and power cable that comprises electric conductors for e.g. 230 V AC. It is also possible that the supply sledge 104 comprises a DC-DC and / or a DC-AC converter configured to convert the DC voltage of the direct voltage rails 102 and 103 into one or more voltages suitable for one or more devices which need electricity within the supply sledge 104. In this exemplifying case, the supply sledge 104 may further comprise an energy storage e.g. a battery for supplying energy in situations in which energy cannot be taken from the direct voltage rails 102 and 103. Figure 2 shows a schematic section view of a part of an electric charging system according to an exemplifying and non-limiting embodiment. The geometric section plane is parallel with the xz-plane of a coordinate system 299 and perpendicular to the longitudinal direction of direct voltage rails 202 and 203, a support beam 221 , and an elongated gutter 214. The electric charging system comprises a supply sledge 204 that is partly in the elongated gutter 214 and is moveable along the direct voltage rails 202 and 203. In this exemplifying electric charging system, the upper rims of the elongated gutter 214 are above the ground level and the upper rims are beveled to make it easier to drive over the elongated gutter 214 with a vehicle. The fact that the upper rims of the elongated gutter 214 are above the ground level reduces the risk that water and dirt get into the elongated gutter 214.
[0045] The supply sledge 204 comprises a force-control system configured to change, responsive to a control signal 213, contact forces between contact elements 205 and 206 and the direct voltage rails 202 and 203. The force-control system comprises a support control system 233 that is configured to control a mechanical support of the supply sledge 204 with respect to the support beam 221 by changing a distance D shown in figure 2. The support control system 233 may comprise e.g. one or more threaded rods which is / are rotated with a servomotor, or which are nonrotating and one or more threaded elements surrounding the one or more threaded rods is / are rotated with a servomotor. For a further example, the support control system 233 may comprise a worm gear meshing with a toothed bar. The embodiment illustrated in figure 2 is however not limited to any specific ways to implement the support control system 233.
[0046] When the above-mentioned distance D is increased, the supply sledge 204 moves upwards, i.e. in the positive z-direction of the coordinate system 299, and therefore the contact elements 205 and 206 get off the direct voltage rails 202 and 203. Correspondingly, when the distance D is decreased the weight of the supply sledge
[0047] 204 gets more and more carried by the contact forces between the contact elements
[0048] 205 and 206 and the direct voltage rails 202 and 203. In this exemplifying case, the contact element 205 does not need to be hinged or otherwise movable with respect to an electric conductor 207 connecting the contact element 205 to a first end 210 of a charging cable 209. Correspondingly, the contact element 206 does not need to be hinged or otherwise movable with respect to an electric conductor 208 connecting the contact element 206 to the first end 210 of the charging cable 209.
[0049] The electric charging system illustrated in figure 2 may comprise a control system 234 that is configured to carry out a loading-handshake after connecting a charging plug to a charging socket of an electric vehicle and to form the above-mentioned control signal 213 so that the contact forces between the contact elements 205 and 206 and the direct voltage rails 202 and 203 are increased in response to the loading-handshake and decreased after charging the electric vehicle. It is however also possible that the control signal 213 is generated manually via a user interface in conjunction when connecting a charging plug to a charging socket of an electric vehicle. It is to be noted that the embodiment illustrated in figure 2 is not limited to any specific ways to generate the control signal 213 to control the contact forces between the contact elements 205 and 206 and the direct voltage rails 202 and 203.
[0050] Figure 3 shows a schematic top view of a truck terminal according to an exemplifying and non-limiting embodiment for electric trucks. The truck terminal comprises a direct voltage power supply system 349 and loading docks 342, 343, 344, and 345. Each of the loading docks 342-345 is suitable for receiving a back of an electric truck for loading and unloading goods through the back of the electric truck. In the exemplifying situation shown in figure 3, an electric truck 353 is at the loading dock 342, an electric truck 354 is at the loading dock 344, and the loading docks 343 and 345 are empty. In figure 3, the longitudinal direction of the electric trucks 353 and 354 is parallel with the y-axis of a coordinate system 399.
[0051] Each of the loading docks 342-345 comprises an electric charging system according to an exemplifying and non-limiting embodiment so that the direct voltage rails of the electric charging system are perpendicular to the loading dock and parallel with a longitudinal direction of an electric truck when the electric truck is at the loading dock. In figure 3, the supply sledge of the electric charging system of the loading dock 342 is denoted with a reference 304.
[0052] The direct voltage power supply system 349 constitutes the direct voltage power supplies of the electric charging systems of the loading docks 342-345. In figure 3, the direct voltage power supply of the loading dock 342 is denoted with a reference 301 . In the exemplifying truck terminal illustrated in figure 3, the direct voltage power supply system 349 comprises alternating current - direct current “AC-DC” converters so that each loading dock has one of the AC-DC converters. Each of these AC-DC converters can be connected separately to an AC power grid or there can be e.g. a common transformer connected to the AC power grid and arranged to supply energy to the AC-DC converters. The AC power grid is not shown in figure 3. It is also possible that a direct voltage power supply system of a truck terminal according to an exemplifying and non-limiting embodiment comprises a common AC-DC converter and each loading dock has a DC-DC converter. The DC-DC converters can be in the vicinity of the ends of the direct voltage rails near to a building 347 of the truck terminal, and the DC-DC converters can be connected to the direct voltage rails with rigid bars or with flexible cables. Depending on power levels, it may be also possible that the DC-DC converters are in the supply sledges. Thus, truck terminals according to embodiments of the invention are not limited to any specific architecture or architectures of the direct voltage power supply system.
[0053] In the exemplifying truck terminal illustrated in figure 3, a cooling system of the direct voltage power supply system 349 comprises an adjustable heat transfer channeling 346 switchable to a first position in which the adjustable heat transfer channeling is configured to give off heat inside the building 347 of the truck terminal and to a second position in which the adjustable heat transfer channeling is configured to give off heat outside the building 347. The first position is suitable for cases, e.g. during a winter, where power losses of the direct voltage power supply system 349 are wanted to be used for warming up the building 347 of the truck terminal, whereas the second position is suitable for cases, e.g. during a summer, where there is a desire to avoid warming up the building 347. The power losses of the direct voltage power supply system 349 can be tens of kilowatts because charging powers related to the loading docks 342-345 can be on megawatt-level.
[0054] The above-mentioned cooling system can be for example a liquid cooling system in which case the adjustable heat transfer channeling 346 is a liquid circulation channeling, a heatsink 352 inside the building 347 can be a heat exchanger as well as a heatsink 351 outside the building 347 can be a heat exchanger. It is also possible that the cooling system is an air cooling system in which case the adjustable heat transfer channeling 346 can be a flow-through channeling, the heatsink 352 inside the building 347 can be simply an open end of a channel for blowing warm cooling air into the interior of the building 347, and correspondingly the heatsink 351 outside the building 347 can be an open end of a channel for blowing warm cooling air to the ambient air outside the building 347. In the exemplifying truck terminal illustrated in figure 3, the AC-DC converters of the direct voltage power supply system 349 are located inside the building 347. This is a suitable arrangement for a cold atmosphere because a part of power losses which is not carried by cooling air or cooling liquid within the channeling 346, but which is emitted to surroundings through e.g. casings of the AC-DC converters warms up the building 347.
[0055] Figure 4 shows a schematic top view of a truck terminal according to an exemplifying and non-limiting embodiment for electric trucks. The truck terminal comprises a direct voltage power supply system 449 and loading docks 442, 443, 444, and 445. Each of the loading docks 442-445 is suitable for receiving a back of an electric truck for loading and unloading goods through the back of the electric truck. In the exemplifying situation shown in figure 4, an electric truck 453 is at the loading dock 442, an electric truck 454 is at the loading dock 444, and the loading docks 443 and 445 are empty. In figure 4, the longitudinal direction of the electric trucks 453 and 454 is parallel with the y-axis of a coordinate system 499.
[0056] Each of the loading docks 442-445 comprises an electric charging system according to an exemplifying and non-limiting embodiment so that the direct voltage rails of the electric charging system are perpendicular to the loading dock and parallel with a longitudinal direction of an electric truck when the electric truck is at the loading dock. In figure 4, the supply sledge of the electric charging system of the loading dock 442 is denoted with a reference 404.
[0057] The direct voltage power supply system 449 constitutes the direct voltage power supplies of the electric charging systems of the loading docks 442-445. In figure 4, the direct voltage power supply of the loading dock 442 is denoted with a reference 401. The direct voltage power supply system 449 comprises AC-DC converters each of which comprises an adjustable heat transfer channeling switchable to a first position in which the adjustable heat transfer channeling is configured to blow warm cooling air into the interior of a building 447 of the truck terminal and to a second position in which the adjustable heat transfer channeling is configured to blow the warm cooling air to the ambient air outside the building 447. In the exemplifying truck terminal illustrated in figure 4, the AC-DC converters of the direct voltage power supply system 449 are located outside the building 447. This is a suitable arrangement for a hot atmosphere because a part of power losses which is not carried by the above-mentioned cooling air, but which is emitted to surroundings through e.g. casings of the AC-DC converters does not warm up the building 447.
[0058] In the exemplifying truck terminal illustrated in figure 4, the direct voltage power supply system 449 comprises a switch module 448 comprising controllable switches capable of connecting each of the AC-DC converters to supply electric energy to the direct voltage rails of desired one or more of the loading docks 442-445. Therefore, desired one or more of the AC-DC converters can be connected to supply electric energy to desired one or more of the loading docks 442-445. The AC-DC converters shown in figure 4 can be separate AC-DC converters or they can be converter modules of a modular AC-DC converter system such that each of the modules has a module-specific direct voltage outlet. It is also possible that the direct voltage power supply system 449 comprises one or more AC-DC converters configured to supply one or more DC intermediate circuits and DC-DC converters supplied by the one or more DC intermediate circuits and having direct voltage outlets each of which can be connected, with the aid of the switch module 448, to supply electric energy to the direct voltage rails of desired one or more of the loading docks 442-445. Thus, different AC-DC conversion systems are possible for supplying electric energy from an AC power 450 grid to direct voltage outlets of the kind mentioned above. Furthermore, the AC-DC conversion system can be configured to be bi-directional so that electric energy can be transferred from a battery of an electric truck to the AC power grid 450.
[0059] In the exemplifying case illustrated in figure 4, the switch module 448 enables the direct voltage outlets of the AC-DC converters to be connected in parallel with each other. It also possible that a switch module enables series connections between the direct voltage outlets of the AC-DC converters and / or mixed parallel-series connections between the direct voltage outlets of the AC-DC converters, e.g. a parallel connection of series connected sub-groups of the AC-DC converters and / or a series connection of parallel connected sub-groups of the AC-DC converters.
[0060] The specific examples provided in the description given above should not be construed as limiting the scope and / or the applicability of the invention. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.
Claims
What is claimed is:
1. An electric charging system for charging an electric vehicle, the electric charging system comprising:- a direct voltage power supply (101 , 301 , 401 ),- direct voltage rails (102, 103, 202, 203) connected to the direct voltage power supply and thus having a direct voltage therebetween and being i) bars of rigid and electrically conductive material and ii) parallel with each other, and- a supply sledge (104, 204, 304, 404) moveable along the direct voltage rails, wherein the supply sledge comprises contact elements (105, 106, 205, 206) configured to form galvanic contacts with the direct voltage rails and electric conductors (107, 108, 207, 208) having lower parts galvanically connected to the contact elements and upper parts galvanically connected to a first end (110, 210) of a charging cable (109, 209), the first end of the charging cable being higher in a vertical direction (z) than the direct voltage rails, and a second end of the charging cable being provided with a charging plug (111 ) connectable to a charging socket of the electric vehicle, characterized in that the supply sledge comprises a forcecontrol system configured to change, responsive to a control signal (113, 213), contact forces between the contact elements (105, 106, 205, 206) and the direct voltage rails (102, 103, 202, 203).
2. An electric charging system according to claim 1 , wherein the direct voltage rails (102, 103, 202, 203) are within an elongated gutter (114, 214) opening upwards and having a longitudinal direction parallel with a longitudinal direction of the direct voltage rails (102, 103, 202, 203).
3. An electric charging system according to claim 2, wherein the elongated gutter (114, 214) is at least partly below ground level.
4. An electric charging system according to claim 3, wherein upper rims of the elongated gutter (114) are in flush with ground level.
5. An electric charging system according to any one of claims 2-4, wherein the electric charging system comprises an underground drain (116) being lower in the vertical direction (z) than a bottom of the elongated gutter, and the bottom of the elongated gutter comprises apertures (117-120) to allow water to leave the elongated gutter.
6. An electric charging system according to any one of claims 1 -5, wherein the electric charging system comprises a support beam (121 , 221 ) parallel with the direct voltage rails and electric insulator elements (122, 123) configured to mechanically support the direct voltage rails with respect to the support beam.
7. An electric charging system according to claim 6, wherein the support beam (121 , 221 ) is between the direct voltage rails (102, 103, 202, 203) so that any geometric line between the direct voltage rails intersects the support beam.
8. An electric charging system according to claim 6 or 7 when depending on claim 2, wherein an upper surface of the support beam (121 , 221 ) is in flush with upper rims of the elongated gutter (114, 214).
9. An electric charging system according to claim 7 or 8 when depending on claim 2, wherein there are elongated gaps between upper rims of the elongated gutter (114, 214) and an upper part of the support beam (121 , 221 ) on both sides of the support beam, and a first one (107) of the electric conductors is configured to extend to a first one (105) of the contact elements via a first one of the elongated gaps and a second one (108) of the electric conductors is configured to extend to a second one (106) of the contact elements via a second one of the elongated gaps.
10. An electric charging system according to claim 9, wherein each of the elongated gaps is provided with elongated and flexible lip elements (124, 125, 224, 225) attached to edges of the elongated gap, being against each other to close the elongated gap, and being bent by the supply sledge to allow the electric conductors to extend via the elongated gaps to the contact elements.
11. An electric charging system according to any one of claims 6-10 when depending on claim 2, wherein the support beam (121 , 221 ) is on an elevation (126, 226) on a bottom of the elongated gutter (114, 214) so that a lower surface of thesupport beam is higher in the vertical direction (z) than a part of an upper surface of the bottom of the elongated gutter.
12. An electric charging system according to any one of claims 6-11 , wherein the support beam (121 , 221 ) is an i-profile beam so that a middle part (127) of the i- profile beam is vertical when seen along a longitudinal direction of the i-profile beam, the middle part (127) of the i-profile beam is between the direct voltage rails (102, 103, 202, 203), and an upper part (128) of the i-profile beam covers the direct voltage rails when seen from above.
13. An electric charging system according to any one of claims 6-12, wherein the support beam (121 , 221 ) is galvanically connected to ground potential.
14. An electric charging system according to any one of claims 1 -13, wherein the electric conductors (107, 108, 207, 208) of the supply sledge (104, 204) are bars of rigid and electrically conductive material.
15. An electric charging system according to any one of claims 1 -14, wherein the force-control system comprises electromagnets (129, 130) configured to press the contact elements (105, 106) against the direct voltage rails (102, 103) in response to electric currents supplied to the electromagnets.
16. An electric charging system according to claim 15, wherein the force-control system comprises springs (131 , 132) configured to detach the contact elements (105, 106) from the direct voltage rails (102, 103) in absence of the electric currents of the electromagnets.
17. An electric charging system according to claim 15 or 16, wherein the electromagnets (129, 130) are configured act against a gravity force when pressing the contact elements (105, 106) against the direct voltage rails (102, 103), the gravity force detaching the contact elements from the direct voltage rails in absence of the electric currents of the electromagnets.
18. An electric charging system according to any one of claims 1 -14, wherein the force-control system comprises a support control system (233) configured to control a mechanical support of the supply sledge (204) with respect to a support beam(221 ) and to allow, responsive to the control signal, the supply sledge to move downwards by gravity so that weight of the supply sledge is at least partly carried by the contact forces between the contact elements (205, 206) and the direct voltage rails (202, 203).
19. An electric charging system according to any one of claims 1 -18, wherein the electric charging system comprises a control system (134, 234) that is configured to carry out a loading-handshake after connecting the charging plug to the charging socket of the electric vehicle and to form the control signal (113, 213) so that the contact forces between the contact elements (105, 106, 205, 206) and the direct voltage rails (102, 103, 202, 203) are increased in response to the loadinghandshake and decreased after charging the electric vehicle.
20. An electric charging system according to any one of claims 1 -19, wherein the electric charging system comprises a servomotor (135) configured to move the supply sledge along the direct voltage rails, a sensor system configured to produce sensor data indicative of a position of the electric vehicle when the electric vehicle is on a charging area of the electric charging system, and a controller (136) configured to control the servomotor to move the supply sledge to a position determined by the sensor data.21 . An electric charging system according to claim 20, wherein the sensor system comprises one or more of following configured to detect the front of the electric vehicle: a laser sensor (137), a radio sensor, an ultrasonic sensor, a machine vision system, one or more inductor loops in / on a ground of the charging area of the electric charging system.
22. An electric charging system according to any one of claims 1 -21 , wherein the supply sledge comprises cooling ducts (138) configured to circulate cooling fluid to cool at least a part of elements configured to conduct electric current for charging the electric vehicle, and the electric charging system comprises a heat-exchanger (139) configured to transfer heat away from the cooling fluid.
23. An electric charging system according to any one of claims 1-22, wherein charging power transferable via the supply sledge is at least 200 kW.
24. A truck terminal comprising a direct voltage power supply system (349, 449) and one or more loading docks (342-345, 442-445) each being suitable for receiving a back of an electric truck for loading and unloading goods through the back of the electric truck, wherein each of the one or more loading docks comprises an electric charging system according to any one of claims 1 -23 so that the direct voltage rails of the electric charging system are perpendicular to the loading dock and parallel with a longitudinal direction (y) of the electric truck when the electric truck is at the loading dock, and wherein the direct voltage power supply system of the truck terminal constitutes the direct voltage power supply of the electric charging system of each of the one or more loading docks.
25. A truck terminal according to claim 24, wherein a cooling system of the direct voltage power supply system (349, 449) comprises an adjustable heat transfer channeling (346) switchable to a first position in which the adjustable heat transfer channeling is configured to give off heat inside a building (347) of the truck terminal and to a second position in which the adjustable heat transfer channeling is configured to give off heat outside the building of the truck terminal.
26. A truck terminal according to claim 24 or 25, wherein the direct voltage power supply system (449) comprises an alternating voltage-direct voltage (AC-DC) conversion system configured to transfer electric energy from an alternating current (AC) power grid to direct voltage outlets of the alternating voltage-direct voltage conversion system and a switch module (448) comprising controllable switches capable of connecting each of the direct voltage outlets to supply electric energy to the direct voltage rails of the electric charging system of any one or more of the loading docks (442-445).