Charging station for charging electrical energy storage device of electric or hybrid vehicle

Abstract

The invention relates to a charging station (4) for charging an electrical energy storage device (2) of a vehicle (1), in particular a road or rail vehicle, comprising a current collector (5) having at least one contact slide (10) that can be raised and lowered, for feeding energy from a single-pole or two-pole overhead line system. The charging station (4) comprises at least one charging contact (11) for each contact pole (9), which charging contact is arranged above the charging position of the vehicle (1) such that at least one contact point (14) can be established between the contact slide (10) and the charging contact (11) for each contact pole (9). Since the charging contact (11) of the charging station (4) according to the invention has a cooling body (15) for cooling the contact point (14), the charging process can be carried out with a higher charging current and thus a shorter charging time.

Description

[0001] The present invention relates to a charging station for charging an energy storage device of an electric or hybrid electric vehicle, particularly a road or rail vehicle, in a stationary state, as described in the preamble of claim 1.

[0002] A charging station for charging an energy storage device of an electrically driven rail vehicle is known from published patent application DE 10 201 0 029 450 A1. To supply power to the electric drive unit of the rail vehicle, a circuit is provided, which is also connected to the energy storage device and controls the charging of the energy storage device via two electrical contacts. The circuit has a switch through which energy can be supplied from the charging station to the energy storage device and / or the drive unit. A first electrical contact is designed as a contact between an overhead line and a current collector for electrical contact with the energy source of the charging station. A second electrical contact of the charging station is formed between the wheels of the rail vehicle and the track. The energy source is connected to the overhead line and the track on which the wheels travel. For example, a positive voltage connector of the energy source is connected to the overhead line, and a negative voltage connector is connected to the track via a power supply line. The energy storage device is directly or via circuit connected to another power supply line to the negative voltage connector of the charging station. The circuit is designed to regulate the voltage and / or current between the energy storage device and the charging station before establishing or discontinuing the electrical connection between the vehicle and the charging station, such that little or no current flows through the electrical contacts when the electrical connection is established or discontinued.

[0003] As known from the published patent application DE 10 201 7 203 046 A1, in electric or hybrid electric road vehicles, energy storage devices are charged during operation by feeding energy from a bipolar overhead line system using a vehicle-side current collector. The current collector includes a pantograph-shaped frame supporting a rocker arm with two contact strips for each contact pole. During operation, the contact strips of each contact pole slide into contact with the contact wire assigned to the corresponding contact pole, allowing direct feeding of electrical energy for traction and charging of the energy storage device. Conversely, when the vehicle is stationary, the point-like contact points between the contact strips and the contact wires do not move, and there is no cooling air; therefore, the power supply current intensity must be chosen low enough to prevent damage to the contact strips and / or contact wires due to overheating. Consequently, charging the energy storage device when the vehicle is stationary is very time-consuming.

[0004] A charging station for charging an electrical energy storage device of a road vehicle is known from published patent application DE 10 201 9 214 552 A1. The charging station has a current collector with at least one raiseable and lowerable contact strip for feeding energy from a bipolar overhead line system. The charging station includes at least two charging contacts for each contact pole, arranged above and adjacent to each other at the charging position of the road vehicle, such that at least two contact points can be created between the contact strip and the charging contacts for each contact pole. The electrical contact between the overhead line system and the road vehicle is formed by a large number of contact points through which charging power is transferred. The heat generated by the current at each contact point decreases with the increase in the number of contact points and can be better dissipated due to the spatial distribution of the contact points. Due to limitations in vehicle weight and size, the size of the contact strip is predetermined, allowing for higher charging current intensities with two or more charging contacts, thereby reducing charging time. The number of charging contacts can vary depending on the desired charging current intensity; preferably, two, three, or four charging contacts are provided.

[0005] Publicly available patent application DE 10 2019 214 708 A1 discloses a charging station for charging the electrical energy storage device of a road vehicle when stationary, such as at a freight transfer point, vehicle depot, or parking lot where no overhead power line system is available. To feed power from a bipolar overhead power line system while in motion, the road vehicle has a current collector, and each contact pole has at least one raiseable and lowerable contact strip. For each contact pole, the charging station includes at least one charging contact element. The charging contacts are arranged above the charging position of the road vehicle, for example on a charging pole, and are arranged adjacent to each other such that at least one contact portion can be created between the contact strip and the charging contact element at each contact pole. At least one charging contact element has a contact body at its lower end, which includes a pad that can deform under the pressure of the current collector and a conductive flexible housing. The lower end of the charging contact element faces the contact strip of the road vehicle in the charging position, such that a contact connection can be established between the contact strip and the contact body by raising the contact strip. Because the contact body has a deformable pad and a flexible cover, a large contact area is formed with the contact body of the charging contact when the contact slider is pressed, for the transmission of charging current. This reduces the current density and the associated heating of the contact slider.

[0006] Therefore, the object of the present invention is to provide a charging station of the type mentioned at the beginning, which can shorten the charging time when the vehicle is stationary.

[0007] This objective is achieved by a charging station having the features described in claim 1. Therefore, the charging station is designed and configured to charge the energy storage device of a vehicle having a pantograph with at least one raiseable and lowerable contact strip for feeding energy from an overhead line system alongside the track during travel. The vehicle can be a rail vehicle with grounded wheels, whose current collector has at least one contact strip for electrical contact with the contact wires of a single-pole overhead line system. The vehicle can also be a road vehicle with rubber-tired wheels, whose pantograph has at least one contact strip for electrical contact with the two contact wires of a two-pole overhead line system. The charging station includes at least one charging contact for each contact pole, arranged, for example, on a charging rod above the vehicle's charging position, such that at least one contact portion can be created between the contact strip and the charging contact for each contact pole. According to the invention, at least one charging contact has a cooling body for cooling the contact portion. The cooling body can be designed as a separate component or integrated into the charging contact. As a result, the conductive contact portion of the charging contact, which may be made of copper or other metallic materials, can be effectively cooled. According to the design, the cooling body can be actively or passively cooled so that the heat generated by the current under a higher charging current of more than 100 A can be dissipated through the cooling body, thereby shortening the charging time.

[0008] In an advantageous embodiment of the charging station according to the invention, the cooling body has at least one cooling channel with a closed cooling circuit in which cooling fluid circulates. The cooling channel system can actively deliver moving cooling air to the contact area via a conveying device and move it away from the contact area after absorbing electrical heat. The route and cross-section of the cooling channel can be adapted to the size and shape of the charging contact or its cooling body using optimization methods. The cooling channel can be formed by straight or serpentine pipes or channels, and can also be combined with cooling fins.

[0009] In another advantageous embodiment of the charging station according to the invention, the cooling body has an open structure through which a cooling fluid flows. The cooling body is distributed with a large number of interconnected small cavities. This structure can be formed, for example, from metal foam and has a very large inner surface along which the cooling fluid (e.g., cooling air) flows and can absorb and remove the electrical heat generated in the charging contacts during the charging process. This allows the energy storage device to be charged at a higher charging current.

[0010] In another advantageous embodiment of the charging station according to the invention, the opening structure is designed such that the flowing cooling fluid exits the cooling body in the direction of the contact area. The opening structure may be unclosed, particularly on the side facing the contact area between the charging contact and the contact slider, or it may have means for guiding the cooling fluid to the contact area, such as flow channels or baffles, which also causes the contact slider to be cooled by the emerging cooling fluid. This reduces the temperature of the two contact partners (charging contact and contact slider), thereby allowing the use of a higher charging current.

[0011] In another advantageous embodiment of the charging station according to the invention, the cooling body has at least one latent heat storage element. Preferably, the cooling body may have a closed-cell metal structure with a large inner surface area, wherein a large number of latent heat storage elements are uniformly distributed. The latent heat storage elements absorb and store the current heat generated in the charging contacts or their cooling body, such that during charging, the current heat does not cause, or only to a small extent causes, an increase in the temperature of the charging contacts. In this way, the latent heat storage elements stabilize the surrounding thermally and electrically conductive structures for the transmission of charging current. After the charging process, for example when the vehicle is in motion, the stored energy is released again by the latent heat storage elements, allowing them to enter a state for newly absorbed energy during the next charging process.

[0012] In another advantageous embodiment of the charging station according to the invention, the latent heat storage is designed as an encapsulated phase change material integrated into the cooling body. The phase change material utilizes the effect that during a phase change, e.g., from a solid to a liquid phase, the material's temperature does not rise despite a continuous supply of heat energy until the phase change is complete. During the phase change, much more energy than is required to heat the material in one phase can be absorbed and stored. After the charging process ends, the absorbed energy is uniformly released again, causing the material to transition from a liquid to a solid phase. Phase change materials can be, for example, based on paraffin or salts and can be tuned to almost any temperature range. They have different energy densities and storage capacities, which can be optimally selected according to their respective applications. Phase change materials that change from a liquid to a gaseous state by absorbing energy can also be used, but it should be noted that the volume increase associated with the phase change is greater than that using materials that change from a solid to a liquid state. This may require measures due to the encapsulation of the phase change material.

[0013] In another advantageous embodiment of the charging station according to the invention, the latent heat storage package has a compensating volume in addition to the phase change material. By taking into account the small compensating volume in each individual reservoir of the phase change material in the form of partially filled capsules, the problem of material volume increase during phase change can be controlled without placing the metal structure of the coolant under excessive mechanical stress.

[0014] In another advantageous embodiment of the charging station according to the invention, the latent heat storage package has a flexible compensation membrane that separates the internal volume of the package from the compensation channels of the cooling body. If the package is completely filled with phase change material, the volume increase during the phase change can be compensated by the expansion of one or more flexible compensation membranes of the package, which allows the material to expand into one or more compensation channels to the outside.

[0015] In another advantageous embodiment of the charging station according to the invention, the cooling body has at least one thermochemical heat storage element. Thermochemical heat storage, some of which has a higher energy density, can also be used as an alternative to or supplement to latent heat storage. For example, thermochemical heat storage elements based on metal hydrides or zeolites store the electrothermal energy generated during the charging process in the cooling body through an endothermic reaction and then release it through an exothermic reaction. Care must be taken to ensure that the heat storage in the conductive structure of the cooling body is distributed sufficiently uniformly to achieve optimal energy dissipation. This can preferably be optimized using an evolutionary algorithm. An evolutionary algorithm is a natural, stochastic optimization method in which candidate solutions (here: the distribution of heat storage in the cooling body) are artificially evolved for a specific problem (here: the large amount of heat absorption of the heat storage).

[0016] In another advantageous embodiment of the charging station according to the invention, the charging contact has a contact side facing the contact slide, and a plurality of contact wires are arranged on the contact side. The conductive contact wires increase the current transmission area between the charging contact and the contact slide, because in reality, there is no flat contact surface between the charging contact and the contact due to wear, such as cracking and uneven wear on the carbon contact of the contact slide. The increased contact area due to the large number of contact wires (which can also be designed to be elastic or flexurally resilient) increases the contact quality between the contact slide and the charging contact while maintaining the same pressure, which in turn allows for an increased charging current. The contact wires can protrude from the contact side of the charging contact in a columnar or rod-like, helical, tubular, or mesh-like manner, and may have barbs, for example, similar to hook-and-loop fasteners. The contact wires can be integrally formed with the charging contact using a 3D printer via direct metal laser sintering. The optimization of the contact element is based on the maximum charging current that can be transmitted under a given pressure, and in addition to the contact area, the maximum heat that can be removed from the carbon is also considered.

[0017] Further advantages and features of the present invention arise from the following description of exemplary embodiments based on the accompanying drawings, wherein the description is schematic:

[0018] Figure 1 A front view of a road vehicle located in a charging station according to the invention is shown.

[0019] Figure 2 Show Figure 1Front view of the contact slider and charging contacts of the middle contact electrode.

[0020] Figure 3 A first exemplary embodiment of a cooling body for charging contacts is shown.

[0021] Figure 4 A second exemplary embodiment of a cooling body for charging contacts is shown.

[0022] Figure 5 A third exemplary embodiment of a cooling body for charging contacts is shown.

[0023] Figure 6 A fourth exemplary embodiment of a cooling body for charging contacts is shown.

[0024] according to Figure 1 An electric or hybrid vehicle 1 is positioned in a charging station 4 installed on road 3 to charge its energy storage device 2. Vehicle 1 is designed as a road vehicle and is equipped with a current collector 5 for feeding energy from a bipolar overhead line system while in motion. For simplicity, contact wires 6, designed only as forward and return conductors, are shown above the lane of road 3 adjacent to the charging location. The current collector 5 has, for example, a pantograph-shaped support frame 7 supported on the vehicle 1's frame (not shown) and can be set and folded by a lifting device (also not shown). The support frame 7 carries two contact rockers 8 arranged adjacent to each other when viewed along the vehicle's longitudinal direction X—one for each contact pole 9—each contact rocker equipped with a pair of contact strips 10 arranged front-to-back when viewed along the vehicle's longitudinal direction X and extending along the vehicle's lateral direction Y. If vehicle 1 uses an electrified lane, the contact strips 10 can be slidably contacted with the corresponding contact wires 6 by setting the support frame 7 along the vehicle's vertical direction Z, in order to feed energy from the overhead line system into vehicle 1.

[0025] However, in the exemplary embodiment shown, the charging station 4 is arranged away from the electrified lane and includes a charging contact 11 for each contact pole 9, positioned above the charging position of the vehicle 1. Each contact pole 9 may also have multiple, for example, two or four charging contacts 11. For this purpose, the charging contacts 11 may be connected to a side arm 12 of the charging station 4, which protrudes from a charging mast 13 located on the side of the road 3 above the charging position. Charging voltage is supplied to the charging contacts 11 of the corresponding contact pole 9 via wires (not shown) extending in the charging mast 13 and side arm 12. To charge the energy storage device 2 in the charging station 4, the vehicle 1 is brought into the charging position, where the current collector 5 is installed and its contact strip 10 is thus pressed against the charging contacts 11 to establish charging contact. The pressure acting at the contact portion 14 between the contact strip 10 and the charging contacts 11 may be, for example, 100 N. After contact is established, a charging current of at least 100A is applied, which flows from the associated charging contact 11 into the contact slider 10 via one of the two contact electrodes 9, and flows back from the contact slider 10 into the associated charging contact 11 via the other of the two contact electrodes 9.

[0026] according to Figure 2 At least one charging contact 11 has a cooling body 15 for cooling the contact portion 14. The cooling body 15 can be designed as a separate component or integrated into the corresponding charging contact 11. As a result, the conductive contact portion 14 of the charging contact 11, which may be made of copper or other metallic materials, can be effectively cooled. Depending on the design, the cooling body 15 can be actively or passively cooled so that the heat generated at higher charging currents exceeding 100A can also be dissipated through the cooling body 15, resulting in a shorter charging time.

[0027] In addition, according to Figure 2The charging contact 11 has a contact side 16 facing the contact slider, on which a large number of contact wires 17 are arranged. The conductive contact wires 17 increase the current transmission area between the charging contact 11 and the contact slider 10. The contact 19, carried by the contact holder 18 of the contact slider 10, is typically made of carbon and is subject to wear in actual use. Breakage and uneven wear of the contact 19 can lead to non-uniformity in the contact area 14, which can be compensated for by the large number of contact wires 17. The contact wires 17 can be designed to be elastic or flexurally elastic, and thus increase the contact quality under constant pressure between the contact slider 10 and the charging contact 11, which in turn allows for an increase in charging current. The contact wires 17 can protrude from the contact side 16 of the charging contact 11 in the form of columns or rods, spirals, tubes, or meshes, and may have barbs, for example, such as those used for hook and loop fasteners. The contact wires 17 can be integrally produced with the charging contact 11 using direct metal laser sintering with a 3D printer. Contact element 17 is optimized based on the maximum transferable charging current under a given pressure, and in addition to the contact surface, the maximum heat that can be removed from contact element 19 is also taken into account.

[0028] according to Figure 3 The cooling body 15 has a cooling channel 20 with a closed cooling loop 21 in which cooling fluid circulates. The cooling channel system 20 can actively deliver moving cooling liquid or cooling air to the contact portion 14 via a conveying device 22, and after absorbing electrothermal energy, it can move away from the contact portion 14, where it can release the absorbed heat energy into the environment. The route and cross-section of the cooling channel 20 can be adapted to the size and shape of the charging contact 11 or its cooling body 15 using optimization methods. The cooling channel 20 can be formed by straight or serpentine pipes or channels, and can also be combined with cooling fins.

[0029] according to Figure 4 The cooling body 15 has an open structure through which cooling fluid 23 flows. Here, the cooling body 15 is permeated by a large number of interconnected small cavities 24. This structure can be formed, for example, from metal foam and has a very large inner surface along which cooling fluid 23 (e.g., cooling air) flows and can absorb and carry away the current heat generated in the charging contact 11 during charging. The open structure is specifically designed such that cooling fluid 23, introduced into the cooling body, for example, via a delivery device 22, flows out of the cooling body 15 in the direction of the contact portion 14. The open structure can be unclosed, particularly on the contact side 16 facing the contact portion 14 between the charging contact 11 and the contact slider 10, which further causes the contact slider 10 to be cooled by the cooling fluid 23. This allows for a reduction in the temperature of the two contact partners (charging contact 11 and contact slider 10), and thus allows for the use of a higher charging current.

[0030] according to Figure 5 and Figure 6 The coolant 15 has a closed-cell metal structure with a large inner surface (not shown in detail), and a large number of latent heat storage elements 25 are uniformly distributed within this inner surface. The latent heat storage elements 25 absorb and store the current heat generated in the charging contact 11 or its coolant 15, such that during charging, the current heat does not cause a temperature rise in the charging contact 11 or only causes a minor temperature rise. In this way, the latent heat storage elements 25 stably surround their thermally and electrically conductive structures to transfer the charging current. After the charging process, for example when the vehicle 1 is in motion, the stored energy is released again by the latent heat storage elements 25, thus placing them in a state of newly absorbed energy for the next charging process. Alternatively, the coolant 15 may also have thermochemical heat storage elements instead of the latent heat storage elements 25, some of which have higher energy densities. For example, thermochemical heat storage elements based on metal hydrides or zeolites store the electrothermal heat generated by the charging process in the coolant 15 through an endothermic reaction and subsequently release it again through an exothermic reaction. It is important to ensure that the heat storage in the conductive structure of the coolant 15 is distributed sufficiently uniformly in order to achieve optimal energy dissipation. This can preferably be optimized using an evolutionary algorithm.

[0031] according to Figure 5 and Figure 6 The latent heat storage 25 is designed as an encapsulated phase change material 26 integrated into the cooler 15. The phase change material 26 utilizes the effect that during a phase change, for example from a solid to a liquid phase, the material temperature does not rise despite a continuous supply of heat energy until the phase change is complete. The absorbed energy is uniformly released again after the charging process, causing the material 26 to change from a liquid to a solid phase. The phase change material 26 can be produced, for example, based on paraffin or salt, and can be tuned to almost any temperature range. They have different energy densities and storage capacities, which can be optimally selected according to their respective applications. Phase change materials whose phase changes from liquid to gas by absorbing energy can also be used; however, it should be noted that the volume increase associated with the phase change is greater than that of the material 26 using a phase change from solid to liquid. This may require measures due to the encapsulation 27 of the phase change material 26.

[0032] according to Figure 5 In addition to the phase change material 26, the encapsulation 27 of the latent heat storage 25 also has a compensating volume 28. By taking into account the small compensating volume 28 in each individual reservoir of the phase change material 26 in the form of an encapsulation 27 that is only partially filled, the problem of volume increase of the material 26 during phase change can be controlled without causing excessive mechanical stress on the metal structure cooler 15.

[0033] according to Figure 6The encapsulation 27 of the latent heat storage 25 may have a flexible compensation membrane 29 that separates the internal volume of the encapsulation 27 from the compensation channels 30 of the cooling body 15. If the encapsulation 27 is completely filled with the phase change material 26, the volume increase during the phase change can be compensated by the expansion of one or more flexible compensation membranes 29 of the encapsulation 27, which allows the material 26 to expand toward one or more outwardly directed compensation channels 30.

Claims

1. A charging station (4) for charging an energy storage device (2) of a vehicle (1), particularly a road vehicle or rail vehicle, the vehicle having a current collector (5) for feeding energy from a single-pole or double-pole overhead line device, the current collector having at least one contact strip (10) that can be raised and lowered, the charging station including at least one charging contact (11) for each contact pole (9), the charging contact being arranged above the charging position for the vehicle (1) such that at least one contact portion (14) can be established between the contact strip (10) and the charging contact (11) for each contact pole (9). Its features are, The charging contact (11) has a cooling body (15) for cooling the contact portion (14).

2. The charging station (4) according to claim 1. -The cooling body (15) has at least one cooling channel (20) of a closed cooling circuit (21) in which cooling fluid circulates.

3. The charging station (4) according to claim 1. -in, The cooling body (15) has an open structure through which the cooling fluid flows.

4. The charging station (4) according to claim 3. -in, The opening structure is configured such that the cooling fluid flows out from the cooling body (15) toward the contact portion (14).

5. The charging station (4) according to claim 1. -in, The cooling body (15) has at least one latent heat storage (25).

6. The charging station (4) according to claim 5. -in, The latent heat storage (25) is constructed as an encapsulated phase change material (26) integrated into the coolant (15).

7. The charging station (4) according to claim 6. -The encapsulation (27) of the latent heat storage (25) has a compensation volume (28) in addition to the phase change material (26).

8. The charging station (4) according to claim 6. -The encapsulation (27) of the latent heat storage (25) has a flexible compensation membrane (29), and the internal volume of the encapsulation (27) is separated from the compensation channel (30) drawn from the cooling body (15) by the compensation membrane.

9. The charging station (4) according to claim 1. -in, The cooling body (15) has at least one thermochemical heat storage material.

10. The charging station (4) according to any one of the preceding claims. -The charging contact (11) has a contact side (16) facing the contact slider (10). -in, Multiple contact wires (17) are arranged on the contact side (16).

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