Vehicle charging device with optimized cooling function

Abstract

The invention relates to a vehicle charging device (2) for inductively charging an energy store (7) of a vehicle (1), the vehicle charging device (2) comprising an interface (5) for receiving electrical power, a first part comprising at least one coil, a second part comprising power electronics, the invention relates to a vehicle charging device (2) comprising an interface (5), power electronics configured to convert electric power received with said interface (5) into a defined alternating current, and a cooling system comprising a fluid accelerator, a fluid inlet and a fluid outlet, said cooling system being configured to cool the vehicle charging device (2) with a fluid, where the first and second parts are spatially separate, where the first and second parts are spatially separated, where the first and second parts are separated from each other. The cooling system includes a first cooling path disposed in a first portion and a second cooling path disposed in a second portion, where a fluid inlet is disposed in the first portion and a fluid outlet is disposed in the second portion, and where a fluid accelerator is configured to deliver fluid from the first cooling path to the second cooling path.

Description

Technical Field

[0001] The invention relates to a vehicle charging device for inductively charging an energy storage device of a vehicle. Background Art

[0002] Wireless charging of electric vehicles offers many benefits. For example, charging can be done automatically without driver intervention and operation, providing a seamless user experience.

[0003] In addition, the reliability of the wireless power transmission system is also guaranteed because there are no exposed electrical contacts and mechanical wear. There is no need to operate cables and connectors, and there are no cables, plugs or sockets that may be exposed to moisture and water in outdoor environments, which improves safety and prevents vandalism.

[0004] Inductive power transfer systems designed to transfer up to 11kW of power require active cooling of both the charging equipment and the vehicle-side power receiving unit. This is particularly important when the vehicle charging equipment is contained in a compact housing that includes the power electronics and magnetic components. The combined package must be flat so that the vehicle can move on it.

[0005] Typically, about 500W of power needs to be dissipated at 90% efficiency, with 50% each split between the charger and vehicle sides. Depending on the specific implementation, this power is distributed almost evenly between the magnetic components and the power electronics compartment of the vehicle charging device.

[0006] A technical problem in this area of ​​technology is how to effectively cool the multiple components within the magnetics and power electronics compartments inside the housing of the tablet charger, which have very different cooling requirements: some components have distributed power density, while the heating of other components is very localized.

[0007] Some components can withstand high temperatures, while others require relatively low temperatures. Some components may have large cooling interfaces, while others do not. Some components require additional high voltage protection, which may be detrimental to achieving an efficient cooling interface. Some components need protection from the environment, while others can be exposed to the environment, such as air used as a cooling fluid.

[0008] The present invention provides an improved vehicle charging device. The present invention particularly provides an improved cooling system for the vehicle charging device. The vehicle charging device according to the present invention can achieve a safer, more efficient and faster vehicle charging process. Summary of the invention

[0009] The present invention relates to a vehicle charging device for inductively charging an energy accumulator of a vehicle, the vehicle charging device comprising an interface for receiving electric power, a first part comprising at least one coil, a second part comprising a power electronic device, the power electronic device being configured to convert the electric power received using the interface into a prescribed alternating current, and a cooling system comprising a fluid accelerator, a fluid inlet and a fluid outlet, the cooling system being configured to cool the vehicle charging device using a fluid, wherein the first part and the second part are spatially separated, wherein the cooling system comprises a first cooling path arranged in the first part and a second cooling path arranged in the second part, wherein the fluid inlet is arranged in the first part and the fluid outlet is arranged in the second part, and wherein the fluid accelerator is configured to transport the fluid from the first cooling path to the second cooling path.

[0010] In some embodiments, the second cooling path comprises a cooling geometry configured to dissipate heat from the power electronics to the fluid, in particular, wherein the cooling geometry is formed by at least one fin.

[0011] In some embodiments, the at least one fin is at least partially composed of a thermally conductive material.

[0012] In some embodiments, the at least one fin bifurcates at least a portion of the second cooling path into two or more separate channels.

[0013] In some embodiments, the total cross-sectional area of ​​the fluid inlets is greater than the total cross-sectional area of ​​the fluid outlets.

[0014] In some embodiments, the first portion further comprises a magnetizable element.

[0015] A vehicle charging apparatus as claimed in any preceding claim, wherein the coil is a printed circuit board (PCB) coil.

[0016] In some embodiments, the fluid accelerator comprises a blade.

[0017] In some embodiments, the fluid accelerator comprises an impeller, a turbine, or a fan.

[0018] In some embodiments, the first cooling path includes a first layer and a second layer, wherein the magnetizable element and the coil are positioned between the first layer and the second layer.

[0019] In some embodiments, the magnetizable element is separated from the coil by a thermally and electrically insulating substrate.

[0020] In some embodiments, the second portion includes a first region and a second region.

[0021] In some embodiments, the first region includes a first type of cooling geometry and the second region includes a second type of cooling geometry that is different from the first type of cooling geometry, and wherein the first region includes a first type of power electronic device and the second region includes a second type of power electronic device, wherein a size and / or shape of the first type of cooling geometry is determined based on thermal radiation of the first type of power electronic device and a size and / or shape of the second type of cooling geometry is determined based on thermal radiation of the second type of power electronic device.

[0022] In some embodiments, the first type of power electronic device is a power factor correction (PFC) and the second type of power electronic device is an inverter.

[0023] In some embodiments, the vehicle charging device further includes at least one temperature sensor and a control unit configured to adjust the fluid accelerator based on temperature data obtained using the at least one temperature sensor.

[0024] In some embodiments, the vehicle charging device further includes a housing, wherein the fluid accelerator is fully integrated into the housing.

[0025] In some embodiments, at least a portion of the fluid inlet and at least a portion of the fluid outlet are disposed on opposite sides of a housing of the vehicle charging device.

[0026] In some embodiments, the vehicle charging device further includes a communication unit and a control unit configured to adjust the fluid accelerator based on command data obtained using the communication unit.

[0027] In some embodiments, the fluid is air, wherein the vehicle charging device includes an exhaust unit configured to convey air from the fluid outlet to an environment isolated from a location of the vehicle charging device.

[0028] In some embodiments, the fluid may be a coolant (eg, oil or water), wherein the cooling system further comprises a coolant circulation system having a radiator. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] By way of example only, preferred embodiments of the present invention will now be described more fully with reference to the accompanying drawings, in which:

[0030] Figure 1 and Figure 2 The charging start process of a vehicle 1 with an energy storage device is shown;

[0031] Figure 3 and Figure 4 are abstract views of two exemplary embodiments of the vehicle charging apparatus of the present invention, in horizontal side views;

[0032] Figure 5An exemplary layout of components including the at least one magnetizable element and the at least one coil is shown;

[0033] Figure 6 yes Figure 3 A section view defined by a dash-dot line. DETAILED DESCRIPTION

[0034] Figure 1 and Figure 2 The charging start process of a vehicle 1 with an energy storage device, such as an electric vehicle or a hybrid vehicle, is shown. The vehicle 1 moves over a vehicle charging device 2, which is connected to a power socket 3 via a cable 4 via an interface 5. The charging process starts when the vehicle 1 is manually started or automatically detected. The vehicle 1 has an inductive charging receiver 6, which is located above the vehicle charging device 2. The inductive charging receiver 6 is configured to charge an energy storage device 7 of the vehicle 1.

[0035] Figure 3 and 4 Two exemplary embodiments of the vehicle charging device of the present invention are shown in horizontal side views. Figure 3 The vehicle charging device 8 comprises (a) a first part 9 comprising a compartment 10 with a coil, in particular a Litz wire coil, and (b) a second part 11 comprising power electronics 12 configured to convert the power received from the power socket 3 into a regulated alternating current, in particular a low-frequency alternating current. In the embodiment shown here, the compartment 10 advantageously also comprises a magnetizable element, in particular a ferrite element.

[0036] The vehicle charging device 8 also includes a cooling system, which includes a fluid accelerator 13, a fluid inlet 14 and a fluid outlet 15, and the cooling system is configured to cool the vehicle charging device using a fluid, which in this example is air from the environment. Typically, the fluid inlet and / or the fluid outlet may include a screen for preventing particles or insects from entering the cooling system.

[0037] Still see Figure 3 , the first part 9 and the second part 11 of the vehicle charging device 8 are spatially separated, wherein the first cooling path 16 of the cooling system is arranged in the first part 9, and the second cooling path 17 of the cooling system is arranged in the second part 11. In this example, the first cooling path 16 is located in the lower part of the vehicle charging device 8, and the second cooling path 17 is located in the upper part of the vehicle charging device 8. However, the cooling paths can be arranged in any vertical order or position within the corresponding parts. Specifically, in other embodiments, the first cooling path can also be arranged in the lower part of the vehicle charging device.

[0038] The fluid inlet 14 is arranged in the first part 9, and the fluid outlet 15 is arranged in the second part 11. The fluid accelerator 13 is configured to transport the fluid from the first cooling path 16 to the second cooling path 17, in particular, wherein the fluid accelerator 13 is placed at the boundary between the first part 9 and the second part 11. Specifically, the accelerator 13 is integrated in the housing of the charging device so that it can only draw fluid from the first cooling path and can only discharge fluid into the second cooling path. The integration of the accelerator in the housing reduces its noise level.

[0039] Specifically, the second cooling path 17 differs from the first cooling path 16 in at least one of the following aspects: (a) the total cross-sectional area of ​​the fluid inlet is larger than the total cross-sectional area of ​​the fluid outlet; (b) the volume of the second cooling path is smaller than the volume of the first cooling path, and the average velocity of the fluid passing through the second cooling path is higher; (c) the total inner surface of the second cooling path is higher than the total inner surface of the first cooling path.

[0040] Figure 4 An alternative embodiment 18 of a vehicle charging device is shown, in which a component 19 having one or more magnetizable elements and one or more coils is placed as an intermediate layer between a first layer 20 and a second layer 21 comprised by a first cooling path. The fluid enters the first cooling path 20 via an inlet 27. A recess 22 allows air or fluid from the second layer 21 to reach the bottom of a fluid accelerator 23, which is embodied here as an impeller, which draws air from below and transfers it radially outwards. For the division into the first and second parts and the design of the second part, see Figure 3 Of course, other fluid accelerators are also applicable, such as fans.

[0041] Figure 5 An exemplary arrangement of components including the at least one magnetizable element and the at least one coil is shown, an embodiment of which is Figure 3 and 4 10 or 19). The coil unit 24 is arranged on the upper side to have a minimum distance from the inductive charging receiver 6 of the vehicle 1. The unit 24 is separated from the magnetizable element 26 by a layer 25 made of a material, such as plastic, which is both electrically isolating and, in particular, thermally isolating.

[0042] If the layer 25 also provides thermal isolation, the heat radiation of the coil 24 and the heat radiation of the magnetizable element 26 are separated so that the corresponding heat can be dissipated by the air flowing through the first layer 21 of the first cooling path and the air flowing through the second layer 20 of the first cooling path, respectively. Figure 5 The layout shown in also applies to Figure 3 A variant in which the charger 8 or the coil compartment is located at the bottom of the housing.

[0043] The magnetic components (coil compartment) in the first part and the electronic components in the second part have a very different distribution of heat radiation. In the first part, the heat is relatively evenly distributed throughout the first cooling path, while in the second part, the heat is locally concentrated in the vicinity of the electronic components. These electronic components may include an inverter and, in particular, may also include power factor correction (PFC). Due to the high voltage, the heat generated is considerable and therefore requires effective cooling to enable the vehicle charging device to operate without interference and interruption.

[0044] Dividing the different characteristic components to be cooled by different cooling paths allows effective cooling, wherein only one fluid accelerator is required. Using only one accelerator is advantageous because the amount of heat that needs to be dissipated leads to its relatively large size. However, of course, according to the present invention, the vehicle charging device can have more than one fluid accelerator. The improved efficiency allows the vehicle charging device to adopt a compact single-box construction. The fact that no high-voltage cables are required to the charging device allows the vehicle charging device to accommodate all major components, which improves the overall charging safety and electromagnetic compatibility.

[0045] As previously mentioned, another advantage of an embodiment is low acoustic emissions, since the vehicle charging device allows the fan (fluid accelerator) to be arranged internally, so that the acoustics are encapsulated by the housing of the vehicle charging device.

[0046] Figure 6 yes Figure 3 The section view is defined by the dotted line. Figure 3 yes Figure 6 The cross-sectional view of the dotted line drawn in FIG. Figure 6 As can be seen in the figure, the internal cooling surface of the first cooling path 16 in the first part 9 is smaller than that of the second cooling path 17 in the second part 11. In addition, in the example shown, the fluid flows more slowly (at least on average) and more evenly in the first path 16, due to the larger volume of the first path 16 than the volume of the second path 17. The faster and more tortuous flow in the second path 17 causes turbulence in particular, thereby improving the cooling performance. In the second cooling path 17, the fluid flows faster on average due to the special design of the cooling geometry along the second path 17.

[0047] The impeller 13 draws in preheated air from the first cooling path 16 and releases it radially into the second cooling path 17. Even though the initial temperature of the air in the second cooling path 17 is higher than that in the first cooling path 16, the fluid in the second cooling path 17 can still effectively cool the component because the fluid in the second cooling path 17 has a larger cooling surface.

[0048] In the embodiment shown, the second portion 11 comprises elongated islands (or in other words: fins) along which the thin channels of the second cooling path 17 run. The fins separate the path of the fluid and can increase turbulence depending on their shape. The islands or fins increase the surface with which the fluid is in contact and thus improve the heat dissipation. Further improvements can be brought about when the fins are made of a material with high thermal conductivity, such as aluminum.

[0049] These ways of splitting from a wider channel into many thin channels can be defined as bifurcations. Therefore, in a preferred embodiment, the second cooling path 17 includes a first main bifurcation and a second main bifurcation, wherein the second portion 11 is respectively in the first region ( Figure 6 The bifurcation above the midpoint dash line) and the second area ( Figure 6 The bifurcations below the mid-dash line) include these bifurcations.

[0050] The first area may include a first type of power electronic devices, and the second area may include a second type of power electronic devices, wherein the first main branch is sized and / or shaped according to the heat dissipation characteristics of the first type of power electronic devices (first type cooling geometry), and the second main branch is sized and / or shaped according to the heat dissipation characteristics of the second type of power electronic devices (second type cooling geometry). In this way, the branches can be specifically adjusted to accurately dissipate heat when heat emerges from the two main components. The two different types of power electronic devices are located in the compartment 12, that is, below the second cooling path 17 (or in other embodiments: above). In particular, these two components may include, but are not limited to, inverters and / or power factor correction (PFC).

[0051] In some embodiments (not shown), the fluid inlet and the fluid outlet are strictly separated and arranged on opposite sides of the housing of the vehicle charging device to ensure that the heat-dissipating air outside the fluid outlet is not partially immediately sucked back into the fluid inlet.

[0052] In a further embodiment, the vehicle charging device may include an exhaust unit configured to convey air from the fluid outlet to an environment isolated from the location of the vehicle charging device, i.e., for example, to an adjacent room or to the outside (e.g., if the vehicle charging device is located in a garage). Such an exhaust unit may include a suction device and / or a suction hose.

[0053] A further embodiment provides at least one temperature sensor, based on which the vehicle charging device can be controlled by the control unit. The control unit will then adjust the fluid accelerator (i.e. its rotation speed and / or its activation and deactivation) according to the temperature data obtained using the temperature sensor. Alternatively or additionally, the charging speed / performance can be controlled based on the measured temperature.

[0054] For example, the vehicle charging device (or individual components thereof) may have a specific temperature at which it operates optimally, wherein the specific temperature is different from the ambient temperature. The control unit may then activate / deactivate / regulate the fluid accelerator to achieve and maintain the specific temperature.

[0055] Exemplary locations for such a temperature sensor are: at the fluid inlet; in the first path before entering the fluid accelerator; in the fluid accelerator; at the outlet of the fluid accelerator; at the fluid outlet; adjacent to specific components of the charger (e.g., coil, magnetizable element, inverter, PFC).

[0056] Some embodiments may include a communication unit that receives commands using wired or wireless technology from an external device, such as a smartphone or computer contained in an electric vehicle that is (or is to be) charged by the vehicle charging device. For example, in the case of a scheduled charging process, the fluid accelerator can be activated / deactivated / adjusted according to the planned start of charging or charging progress. Specifically, the vehicle charging device can perform pre-cooling for the planned charging process and / or post-cooling within a specified time after the charging process is completed, or until the desired temperature is reached (monitored by an optional temperature sensor).

[0057] Although the present invention has been described above with reference to some preferred embodiments, it must be understood that various modifications and combinations of the different features of these embodiments are possible. All these modifications are within the scope of the appended claims.

Claims

1. A vehicle charging device (2, 8, 18) for inductively charging an energy storage device (7) of a vehicle (1), the vehicle charging device comprising: An interface for receiving power (5); A first portion (9) comprising at least one coil (24); A second part (11) comprising a power electronic device, the power electronic device being configured to convert the power received through the interface into a prescribed alternating current; as well as A cooling system comprising a fluid accelerator (13, 23), a fluid inlet (14, 27) and a fluid outlet (15), the cooling system being configured to cool a vehicle charging device using a fluid; Features: The first portion and the second portion are spatially separated; The cooling system comprises: a first cooling path (14, 20, 21) arranged in the first portion; and a second cooling path (17) arranged in the second portion; The fluid inlet is arranged in the first portion and the fluid outlet is arranged in the second portion; and The fluid accelerator is configured to transport the fluid from the first cooling path to the second cooling path.

2. The vehicle charging device (2, 8, 18) according to claim 1, wherein the second cooling path (17) comprises a cooling geometry configured to dissipate heat from the power electronics to the fluid, in particular, wherein the cooling geometry is formed by at least one fin.

3. The vehicle charging device (2, 8, 18) according to claim 2, wherein the at least one fin at least partially consists of a thermally conductive material.

4. The vehicle charging device (2, 8, 18) according to claim 3, wherein the at least one fin branches at least a portion of the second cooling path (17) into two or more separate channels.

5. The vehicle charging device (2, 8, 18) according to any one of the preceding claims, wherein the total cross-sectional area of ​​the fluid inlet is greater than the total cross-sectional area of ​​the fluid outlet.

6. The vehicle charging device (2, 8, 18) according to any one of the preceding claims, wherein the first part (9) further comprises a magnetizable element (26).

7. The vehicle charging device (2, 8, 18) according to any one of the preceding claims, wherein the coil (24) is a printed circuit board (PCB) coil.

8. The vehicle charging device (2, 8, 18) according to any one of the preceding claims, wherein the fluid accelerator (13, 23) comprises a blade.

9. The vehicle charging device (2, 8, 18) according to any one of the preceding claims, wherein the fluid accelerator (13, 23) comprises an impeller, a turbine or a fan.

10. The vehicle charging device (2, 8, 18) according to any of the preceding claims, wherein the first cooling path comprises a first layer (20) and a second layer (21), and wherein the magnetizable element (26) and the coil (24) are placed between the first layer and the second layer.

11. The vehicle charging device (2, 8, 18) according to any of the preceding claims, wherein the magnetizable element (26) is separated from the coil (24) by a thermally and electrically insulating substrate (25).

12. The vehicle charging device (2, 8, 18) according to any one of the preceding claims, wherein the second portion (11) comprises a first area and a second area.

13. A vehicle charging device (2, 8, 18) according to claim 13, wherein the first area includes a first type of cooling geometry and the second area includes a second type of cooling geometry different from the first type of cooling geometry, and wherein the first area includes a first type of power electronic device and the second area includes a second type of power electronic device, wherein the size and / or shape of the first type of cooling geometry is determined according to the thermal radiation of the first type of power electronic device and the size and / or shape of the second type of cooling geometry is determined according to the thermal radiation of the second type of power electronic device.

14. The vehicle charging device (2, 8, 18) of claim 14, wherein the first type of power electronic device is a power factor correction (PFC) and the second type of power electronic device is an inverter.

15. The vehicle charging device (2, 8, 18) according to any of the preceding claims, comprising at least one temperature sensor and a control unit configured to regulate the fluid accelerator based on temperature data obtained with the at least one temperature sensor.

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