Wireless charging module comprising a cooling system

Abstract

A wireless charging module (4) comprising a cooling system (8) for dissipating heat which is generated by the wireless charging module (4) during operation thereof, the cooling system (8) having a first coolant connection (81), a second coolant connection (82) and at least one coolant channel (90) through which coolant (80) can flow and which fluidically connects the first coolant connection (81) to the second coolant connection (82), wherein the coolant channel (90), when viewed in cross-section of the coolant channel, is delimited by a wall comprising a top surface (93) which is arranged at the top in an operating state of the loading module (4), a bottom surface (95) arranged at the bottom, and two opposing side surfaces (94), which in each case connect the top surface (93) and the bottom surface (95) to one another, wherein the top surface (93) of the coolant channel (90) runs largely horizontally, wherein the coolant channel (90) comprises at least one bubble collecting region (98) which, in the operating state of the charging module and with respect to an average flow velocity of the coolant in the coolant channel, has a lower flow velocity, wherein at least one narrowing element (97) is arranged in the at least one bubble collecting region (98) in order to form a narrowed section in which, viewed in a main flow direction of the coolant in the coolant channel, a flow cross-sectional area of the coolant channel (90) narrows to a minimum flow cross-sectional area and then increases again.

Description

[0001] WIRELESS CHARGING MODULE WITH COOLING SYSTEM

[0002] The invention relates to a wireless charging module for charging a battery or for powering a consumer of a vehicle.

[0003] Electric vehicle batteries can be charged with alternating current (AC) or direct current (DC). Typical AC chargers can provide a charging power of up to 22 kW. AC charging systems can be divided into wired and wireless charging systems, with wireless charging systems primarily implemented as inductive charging systems (ICS). Wired AC chargers are usually integrated into electric vehicles and are also known as on-board chargers. An ICS typically consists of two separate modules, often referred to as the ground pad module (GPM) and the car pad module (CPM). The GPM is installed outside the electric vehicle, while the CPM is located inside the vehicle, usually on the underside.The electromagnetic interaction between the GPM and the CPM enables energy transfer from the GPM to the CPM and vice versa, and the CPM is then used to charge the electric vehicle's battery. Wireless charging systems are often more convenient for the user, as no manual intervention is usually required to start the battery charging process, other than placing the vehicle over the GPM. The wireless charging module according to the invention can be used, in particular, to charge a high-voltage battery or to store energy for a vehicle's electrical load. In this case, it can be referred to as a Car-Pad Module (CPM). This module can receive an oscillating magnetic field from an external transmitter, which can be called a Ground-Pad Module (GPM).The CPM converts the oscillating electromagnetic, predominantly magnetic field into an alternating current, which is then converted (typically rectified) to a charging current (typically direct current) that is used to charge the battery or power the consumer.

[0004] The wireless charging module can also be referred to as a power conversion device. It serves to convert the electromagnetic power of an oscillating electromagnetic field into electrical power, either as an electric current or as an available electric current for charging an electrical storage device or powering an electrical load.

[0005] Regarding cooling, it is important to understand that a CPM can have two areas of heat generation: an electronic assembly (power electronics) that generates a lot of heat, but is concentrated in certain areas of the device and has a relatively high density of heat-generating elements there, and a magnetic assembly (coil and ferrite) that generates less heat and is spatially relatively widely distributed, i.e., with a low density of heat-generating elements.

[0006] In the cooling systems of charging modules known from the prior art, the problem frequently arises that air can become trapped in areas of the cooling system, particularly in the lines carrying the coolant. Since air is a poor conductor of heat compared to the actual coolant, negatively impacting cooling efficiency, air accumulation in the coolant channels should be avoided or at least minimized.

[0007] The object of the invention is to create a wireless charging module of the type mentioned above, which has improved heat transfer from heat-generating elements to a cooling medium for cooling the charging module.

[0008] This problem is solved by a wireless charging module with the features of claim 1. Further preferred embodiments are shown in the dependent claims.

[0009] The inventive wireless charging module for charging a vehicle battery and / or powering a vehicle consumer and / or supplying energy from the vehicle battery and / or supplying energy from a vehicle energy source comprises a cooling system for dissipating heat generated by the wireless charging module during its operation. The cooling system includes a first coolant connection, a second coolant connection, and at least one coolant channel through which coolant flows, fluidly connecting the first coolant connection to the second coolant connection. In a cross-section of the coolant channel, the channel is bounded by a wall comprising a top surface (arranged at the top in an operating state of the charging module), a bottom surface, and two opposing side surfaces, each connecting the top surface and the bottom surface.The ceiling surface of the coolant channel is mostly horizontal. The coolant channel, and in particular its ceiling surface, includes at least one bubble collection zone which, during the operation of the charging module and with respect to the average flow velocity of the coolant in the coolant channel, exhibits a lower flow velocity. At least one constriction element is arranged in the at least one bubble collection zone to form a constricted section. In this constricted section, the cross-sectional area of ​​the coolant channel narrows to a minimum cross-sectional area in the main flow direction of the coolant and then increases again.

[0010] In other words, the at least one constriction element is designed to cause an increase in the flow velocity of the coolant in the constricted section, in relation to a non-constricted section of the coolant channel that is adjacent upstream to the constricted section in a main flow direction of the coolant in the coolant channel.

[0011] Adding constricting elements to reduce the flow cross-sectional area in areas of the coolant channel with low flow velocity or higher air bubble concentration leads to a local increase in the coolant flow velocity. In the respective constricted sections of the coolant channel, i.e., in the bubble-generating areas, the coolant flow velocity is higher than in the bubble-collecting areas, and thus the air bubbles are carried along by the coolant flow. This allows air bubbles contained in the coolant channel to be transported more quickly through the channel and towards the second coolant connection and / or a venting device, and ultimately removed from the cooling system, making it easier and faster to fill the cooling system with coolant.In general, this can also reduce the amount of air contained in the coolant channel, which has a positive effect on the cooling performance of the coolant system.

[0012] In some embodiments, the wireless charging module further comprises a first, in particular magnetic, assembly for receiving an oscillating electromagnetic field and converting it into an alternating current. The wireless charging module further comprises a second, in particular electronic, assembly for receiving, in particular rectifying, the alternating current and converting it into an electric current for charging the battery or powering the device. In this embodiment, the cooling system is designed to dissipate heat generated by the magnetic and electronic assemblies during operation.

[0013] In embodiments, the at least one bubble collection area, viewed in cross-section of the coolant channel, is arranged in a region with turbulence of the coolant medium. A region with turbulence, viewed in the main flow direction of the coolant, exhibits at least a partially negative flow velocity.

[0014] In embodiments, the lower flow velocity is at most 10% of the mean flow velocity of the coolant in the coolant channel.

[0015] In certain configurations, at least 50% of the coolant channel's ceiling surface runs horizontally. In this case, the advantages of the coolant system are particularly pronounced because the coolant channel has a high number of sections where air bubbles accumulate in areas of low flow velocity.

[0016] In various embodiments, the at least one constriction element extends over 5% to 50%, preferably 5% to 20%, of the cross-sectional area of ​​a non-constricted section of the coolant channel adjacent to the constricted section upstream in the main flow direction. In this area, the desired increase in the coolant flow velocity is achieved without obstructing the coolant flow. In some embodiments, the at least one constriction element is configured to direct air bubbles carried in the coolant from the bubble collection area towards the ceiling surface and towards a bubble generation area. The bubble generation area is characterized by a higher flow velocity during operation of the charging module and relative to the average flow velocity of the coolant in the coolant channel.Such a constriction element promotes the tendency of air bubbles to rise due to their lower density compared to the surrounding coolant, and is therefore particularly advantageous from a fluid dynamics perspective. The higher flow velocity of the coolant prevailing in the bubble-promoting zone and / or generated by the at least one constriction element ensures that the air bubbles are transported quickly and reliably through the coolant channel, for example, to the coolant connection located downstream in the main flow direction of the coolant or to a section of the coolant channel intended for venting the cooling system.

[0017] In some embodiments, the at least one constriction element is arranged at a transition between the top surface and one of the two side surfaces. Here, the flow velocity of the coolant in the coolant channel is generally lowest, so the problem of air bubble accumulation and the effect of the constriction elements are particularly pronounced in these areas.

[0018] In this embodiment, at least one bubble collection area incorporates two constriction elements. Viewed in cross-section of the constricted section, these elements are positioned opposite each other at the transitions between the top surface and the two side surfaces. Due to the tendency of air bubbles to rise to the top surface and accumulate in areas of the coolant channel with low coolant flow velocities, the arrangement of two constriction elements at the opposing transitions of the side surfaces and the top surface is particularly effective in creating a bubble collection area located between the two constriction elements.

[0019] In some embodiments, the bubble-propelling area, viewed in cross-section of the constricted section, is located in a central region of the ceiling surface. In this region, the coolant flow velocity is highest, so that the air bubbles transported in the coolant are propelled particularly quickly and effectively through the coolant channel and ultimately out of the cooling system.

[0020] In embodiments, the bubble conveying zone, viewed in cross-section of the constricted section, extends over less than 80% of the coolant channel's width. Preferably, the bubble conveying zone, viewed in cross-section of the constricted section, extends over less than 50% of the coolant channel's width. In other words, the at least one constriction element, viewed in cross-section of the constricted section, extends over at least 20%, preferably at least 50%, of the coolant channel's width. This allows for a particularly advantageous narrowing of the flow cross-section or increase in flow velocity in the bubble conveying zone compared to the bubble collection zone.

[0021] In certain embodiments, the average flow velocity in the bubble conveying region is at least twice as high as the average flow velocity in the bubble collection region. In particular, the average flow velocity in the bubble conveying region is at least five times, and preferably at least ten times, higher than the average flow velocity in the bubble collection region. This creates a kind of suction effect, which draws the air bubbles from the bubble collection region towards and into the bubble conveying region, aided by the at least one constriction element. In some embodiments, the at least one bubble collection region is limited to a section of the coolant channel.In other words, the at least one bubble collection area, viewed along the coolant channel, does not extend over substantially the entire length of the coolant channel. By locally employing the at least one constriction element, costs can be saved and the flow velocity of the coolant in the coolant channel can be varied locally, in particular increasing it compared to a mean low flow velocity of the coolant in the respective bubble collection area.

[0022] In embodiments, the cooling system comprises a first coolant channel and a second coolant channel, i.e., two coolant channels. Coolant flows through the coolant channels, which fluidically connect the first coolant connection to the second coolant connection. The second coolant channel branches off from the first coolant channel at a junction and, viewed in the main flow direction of the coolant, opens into the first coolant channel downstream of the junction. In other words, the second coolant channel fluidly connects the first coolant connection to the second coolant connection section by section via the first coolant channel, i.e., via the portions of the first coolant channel located upstream of the junction and downstream of the junction.This type of parallel connection of two coolant channels allows the coolant supplied via the first coolant connection to be divided into two coolant flows with different volume flows, thus meeting the different cooling requirements of different components of the wireless charging module. For example, a component of the wireless charging module that generates only a small amount of heat during operation can be cooled via a smaller coolant channel with a smaller flow cross-section. This smaller channel is supplied by a larger coolant channel with a larger flow cross-section, which is intended for cooling a component of the wireless charging module that generates a lot of heat. This allows coolant temperatures to be effectively adjusted depending on the components of the wireless charging module being cooled.

[0023] In embodiments, the length of the at least one constriction element, viewed in the main flow direction of the coolant, is between one and fifty times the distance between the top surface and the bottom surface in the constricted section. Preferably, the length of the at least one constriction element, viewed in the main flow direction of the coolant, is between one and twenty-five times the distance between the top surface and the bottom surface in the constricted section.

[0024] Within the context of this text, the term "length" refers in particular to the characteristic length of the constriction element, i.e., the length of the constriction element in the direction of coolant flow.

[0025] In certain embodiments, the at least one constriction element is formed by a deformation of the coolant channel wall. In other words, the at least one constriction element is integrally formed with the wall. Such an embodiment is particularly cost-effective to manufacture and requires no fasteners to attach the constriction element to the wall.

[0026] In embodiments, the at least one constriction element is designed as a flow body, which is arranged at a transition between the top surface and one of the two side surfaces. The flow body has a substantially square base and, viewed in the main flow direction of the coolant in the coolant channel, a corrugated profile, the height of which decreases from the side surface. For the purposes of this text, a corrugated profile is understood to be a sequence of a concave surface followed by a convex surface followed by another concave surface.

[0027] In embodiments, the at least one constriction element forming the constricted section has a continuous transition to a non-constricted section adjacent to the constricted section upstream in the main flow direction. Alternatively or additionally, the at least one constriction element forming the constricted section has a continuous transition to a non-constricted section adjacent to the constricted section downstream in the main flow direction. Alternatively or additionally, the at least one constriction element forming the constricted section has a continuous transition to the coolant channel in a direction transverse to the main flow direction of the coolant in the coolant channel.

[0028] In the context of this text, a continuous profile is understood to mean that the curvatures of the concave and convex surfaces change continuously. Specifically, a continuous profile exists when the transitions between the convex and concave surfaces are smooth and continuous, and when the transitions between the constriction element and the sections of the coolant channel adjacent to it upstream and downstream in the main coolant flow direction are smooth and continuous. This prevents air bubbles from accumulating in a non-continuous transition zone.

[0029] In embodiments, the flow cross-sectional area of ​​the coolant channel in the constricted section decreases continuously from an unconstricted section adjacent to the constricted section upstream in the main flow direction to the minimum flow cross-sectional area. Alternatively or additionally, the flow cross-sectional area of ​​the coolant channel in the constricted section increases continuously from the minimum flow cross-sectional area to an unconstricted section adjacent to the constricted section downstream in the main flow direction. Alternatively or additionally, the flow cross-sectional area of ​​the coolant channel in the constricted section increases continuously from a side face and in a direction transverse to the main flow direction of the coolant in the coolant channel.

[0030] The invention will now be explained in more detail with reference to preferred embodiments, which are illustrated in the accompanying drawings. These schematically depict:

[0031] Figure 1 A vehicle on a wireless charging station;

[0032] Figure 2 shows a wireless charging station and a wireless charging module;

[0033] Figure 3 shows a wireless charging module;

[0034] Figure 4 shows a wireless charging module in cross-section;

[0035] Figure 5 shows a partially opened wireless charging module; and

[0036] Figure 6 shows a cooling channel structure in a cooling system;

[0037] Figure 7a shows a narrowed section with a narrowing element, in a cross-section A from Figure 6;

[0038] Figure 7b shows a narrowed section with a narrowing element, in a longitudinal section B through the narrowing element from Figure 6,

[0039] The reference symbols used in the drawings and their meanings are summarized in the reference symbol list. Generally, identical parts in the figures are labeled with the same reference symbols.

[0040] Figure 1 shows a schematic side view of a vehicle 2 above a wireless charging station 3, which is located outside the vehicle 2 and includes a transmitter for transmitting an oscillating magnetic field. A wireless charging module 4 for charging a high-voltage battery 5 of the vehicle 2 is arranged above the charging station 3 and inside the vehicle 2.

[0041] Figure 2 shows a more detailed top view of the wireless charging station 3 and the wireless charging module 4 located above it in the vehicle 2, with the other elements not shown. Figure 3 shows a perspective view of the charging module 4, which can also be referred to as a wireless charger. The charging module 4 has a planar structure and comprises a first coolant connection 81 and a second coolant connection 82.

[0042] Figure 4 shows a schematic cross-section through a wireless charging module 4. A first part 41 and a second part 42 form a supporting structure for the other components described. The first part 41 and / or the second part 42 can each be composed of several individual parts. A housing (not shown) may also be present. An electronic assembly 7 is arranged on the first part 41. This generates a relatively high amount of heat in a relatively small space. A magnetic assembly 6 is arranged on or in the second part 42. This assembly comprises coil conductors 62 and ferrite elements 61. Distributed over a larger space, these generate comparatively less heat.

[0043] Between the first part 41 and the second part 42, coolant channels 90a, 90b of a cooling channel structure 9 are formed by recesses in one or both of these parts. The coolant channels 90a, 90b can be sealed by sealing elements 49. The first coolant channel 90a primarily cools parts of the magnetic assembly 6, while the second coolant channel 90b cools the electronic assembly 7 and, in this embodiment, also parts of the magnetic assembly 6. The second coolant channel 90b is therefore designed to dissipate a larger amount of heat per unit time than the first coolant channel 90a. The channels have smooth wall structures 43, i.e., the walls of the channels are essentially smooth and do not cause turbulence in the coolant flow 80.

[0044] Coolant channels can run parallel to each other, or they can be sections with different heat transfer properties to the channel wall. Such different cooling channel sections can be arranged in series within the same coolant channel. They can also be arranged in parallel coolant channels.

[0045] The cooling channel structure 9, together with a first coolant connection and a second coolant connection (both coolant connections not shown in Figure 4), forms a cooling system for the wireless charging module 4.

[0046] Figure 5 shows a partially opened wireless charging module 4, with the second part 42, the magnetic assembly 6, and sealing elements 49 removed. The complete wireless charging module 4 can have a cross-section as shown in Figure 4. In the coolant channel 90, the first cooling section 91 and the second cooling section 92 are arranged sequentially and are sequentially supplied with the same coolant flow 80. A typical section of the coolant channel 90, which exhibits a lower flow velocity in the operating state of the charging module 4 and with respect to a mean flow velocity of the coolant 80 in the coolant channel 90—i.e., a typical bubble collection area—is indicated in Figure 5 by the rectangle shown in dashed lines and labeled with reference numeral 98. Consequently, at least one constriction element is arranged in the bubble collection area 98 (not shown for clarity).

[0047] Figure 6 shows the shape of a cooling channel structure 9 in a cooling system 8. Only the shape of the cavities of the cooling system 8 is shown in a wireframe representation, omitting the shape of the surrounding elements. The cooling channel structure 9 in Figure 6 has two parallel coolant channels 90a and 90b. The first coolant channel 90a has a smaller cross-section and a smaller first coolant flow 80a than the second coolant channel 90b, which has a larger second coolant flow 80b. A typical bubble collection area of ​​the first coolant channel 90a is indicated in Figure 6 by the rectangle shown with dashed lines and labeled with reference numeral 98. At least one constriction element (not shown for clarity) is arranged in the bubble collection area 98.This cooling channel structure 9 and the surrounding elements can have a cross-section as shown in Figure 4 (whereby the structured wall structure 44 is not shown in Figure 6). Figure 6 shows possible positions of the section planes A and B with respect to the embodiment shown in Figure 6 by way of example. A cross-section A and a longitudinal section B according to one embodiment are described in detail in Figures 7a and 7b below.

[0048] Figure 7a shows a section of a cross-section A through a narrowed section of a coolant channel 90, and Figure 7b shows a section of a longitudinal section through the narrowing element from Figure 7a, with the focus in each case on the top surface 93, which is located at the top in the operating state of the charging module. A wall of the coolant channel 90, which can also be referred to as the inside or inner wall of the coolant channel 90, has, in addition to the top surface 93, two side surfaces 94 and a bottom surface, whereby in Figure 7a only a part of one of the side surfaces 94 is shown and the bottom surface is not shown. A narrowing element 97 is arranged at the transition between the top surface 93 and the side surface 94, with the thickening of the top surface 93 caused by the narrowing element being illustrated by the narrowing element.In Figure 7a, a dashed line is drawn on the side surface 94, which describes the course of the top surface 93 without the constricting element 97. In the illustrated embodiment, the wall of the coolant channel 90 has a substantially rectangular cross-section. The top surface 93 runs substantially parallel to the bottom surface. Two opposing side surfaces 94 can run substantially parallel to each other. With such a substantially rectangular cross-sectional shape, the coolant channel 90 can be guided through the flat charging module and past the elements or assemblies to be cooled with the largest possible flow cross-section. The top surface 93 and, optionally, also the coolant channel 90 run substantially horizontally in the installed state of the charging module.

[0049] A bubble formation area 96 is located, viewed in the cross-section of the coolant channel 90, in a central region of the ceiling surface 93. A bubble formation area 96 may be limited to a section in the longitudinal direction of the coolant channel 90. However, it may also extend over a longer section, in particular up to the second coolant connection 82.

[0050] In other embodiments, the invention is implemented in a coolant channel 90 with a different cross-section, specifically regarding the shape of the side surfaces 94 and the bottom surface 95. A common feature is that the accumulation of air bubbles in edge regions 98 is avoided by providing the top surface 93 with a bubble conveying area 96.

[0051] REFERENCE MARK LIST

[0052] 1 Inductive charging system

[0053] 2 vehicles

[0054] 3 Wireless Charging Station (GPM)

[0055] 4 Wireless Charging Module (CPM)

[0056] 41 first part

[0057] 42 Part Two

[0058] 43 smooth wall structure

[0059] 44 structured wall structure

[0060] 49 Sealing element 5 Vehicle battery

[0061] 6 magnetic assembly

[0062] 61 ferrite elements

[0063] 62 coil conductors, 7 electronic assembly

[0064] 8 Cooling system

[0065] 80 Coolant flow

[0066] 81 first coolant connection

[0067] 82 Second coolant connection 9 Cooling channel structure

[0068] 90 Coolant channel

[0069] 90a First coolant channel

[0070] 90b Second coolant channel

[0071] 91 First cooling cut 92 Second cooling cut

[0072] 93 ceiling area

[0073] 94 side surface

[0074] 95 floor area

[0075] 96 Bladder constriction area 97 Constriction element

[0076] 98 Bubble collection area

Claims

PATENT CLAIMS 1. Wireless charging module (4) for charging a battery (5) of a vehicle (2) and / or for powering a consumer of the vehicle (2) and / or for supplying energy from the battery (5) of the vehicle (2) and / or for supplying energy from an energy source of the vehicle (2), with a cooling system (8) for dissipating heat generated by the wireless charging module during its operation, the cooling system (8) comprising a first coolant connection (81), a second coolant connection (82) and at least one coolant channel (90) through which coolant (80) flows, which fluidically connects the first coolant connection (81) to the second coolant connection (82), wherein the coolant channel (90), viewed in a cross-section of the coolant channel (90), comprises a wall comprising a top surface (93) arranged in an operating state of the charging module, a bottom surface (95), and two opposite side surfaces (94),which connect the ceiling surface (93) and the bottom surface (95) respectively, is limited, wherein in the operating state the ceiling surface (93) of the coolant channel (90) is mostly horizontal, wherein the coolant channel (90), in particular the ceiling surface (93), comprises at least one bubble collection area (98) which, in the operating state of the charging module and with respect to a mean flow velocity of the coolant (80) in the coolant channel (90), has a lower flow velocity, wherein at least one constriction element (97) is arranged in the at least one bubble collection area (98) to form a constricted section in which, viewed in a main flow direction of the coolant (80) in the coolant channel (90), a flow cross-sectional area of ​​the The coolant channel (90) narrows to a minimum flow cross-sectional area and then widens again.

2. The wireless charging module (4) according to claim 1, characterized in that the lower flow velocity is at most 10% of the mean flow velocity of the coolant (80) in the coolant channel (90).

3. The wireless charging module (4) according to claim 1 or 2, characterized in that at least 50% of the ceiling area (93) of the coolant channel (90) runs horizontally.

4. The wireless charging module (4) according to one of the preceding claims, characterized in that the at least one constriction element (97) extends over 5% to 50%, preferably over 5% to 20%, of a flow cross-sectional area of ​​a non-constricted section of the coolant channel (90) adjacent upstream to the constricted section in the main flow direction.

5. The wireless charging module (4) according to one of the preceding claims, characterized in that the at least one constriction element (97) is configured to direct air bubbles carried along in the coolant (80) from the bubble collection area (98) towards the ceiling surface (93) and towards a bubble conveying area (96), which, in the operating state of the charging module and with respect to the mean flow velocity of the coolant (80) in the coolant channel (90), has a higher flow velocity.

6. The wireless charging module (4) according to one of the preceding claims, characterized in that the at least one narrowing element (97) is attached to is arranged at a transition between the ceiling surface (93) and one of the two side surfaces (94).

7. The wireless charging module (4) according to claim 6, characterized in that two constriction elements (97) are arranged in the at least one bubble collection area (98), which, viewed in cross-section of the constricted section, are arranged at the transitions between the top surface (93) and the two side surfaces (94) and are positioned opposite each other.

8. The wireless charging module (4) according to one of the preceding claims, characterized in that the bubble feeder area (96), viewed in cross-section of the narrowed section, extends over less than 80%, preferably less than 50%, of the width of the coolant channel (90).

9. The wireless charging module (4) according to one of the preceding claims, characterized in that an average flow velocity in the bubble conveying area (96) is at least twice, in particular at least five times and preferably at least ten times higher than an average flow velocity in the bubble collecting area (98).

10. The wireless charging module (4) according to one of the preceding claims, wherein the at least one bubble conveying area (96), viewed along the coolant channel (90), is limited to a section of the coolant channel (90).

11. The wireless charging module (4) according to one of the preceding claims, characterized in that the cooling system (8) has a first coolant channel (90a) and a second coolant channel (90b) through which coolant (80) can flow and which fluidically connect the first coolant connection (81) to the second coolant connection (82), wherein the second coolant channel (90b) branches off from the first at a branch point coolant channel (90a) branches off and, viewed in the main flow direction of the coolant (80), flows downstream of the branch point into the first coolant channel (90a).

12. The wireless charging module (4) according to one of the preceding claims, characterized in that the length of the at least one constriction element (97), viewed in the main flow direction of the coolant (80), is between one and fifty times, preferably between one and twenty-five times, the distance between the top surface (93) and the bottom surface (95) in the constricted section.

13. The wireless charging module (4) according to one of the preceding claims, characterized in that the at least one constriction element (97) is formed by a deformation of the wall of the coolant channel (90).

14. The wireless charging module (4) according to one of the preceding claims, characterized in that the at least one constriction element is designed as a flow body which is arranged at a transition between the top surface (93) and one of the two side surfaces (94), wherein the flow body has a substantially square base area and, viewed in the main flow direction of the coolant (80) in the coolant channel (90), a wave profile, wherein the height of the wave profile decreases from the side surface.

15. The wireless charging module (4) according to one of the preceding claims, characterized in that, for the constricted section, the flow cross-sectional area of ​​the coolant channel (90) continuously narrows from an unconstricted section adjacent to the constricted section upstream in the main flow direction towards the minimum flow cross-sectional area; and / or continuously increased from the minimum flow cross-sectional area towards a non-narrowed section adjacent to the narrowed section downstream in the main flow direction; and / or continuously increased from a side surface (94) and in a direction transverse to the main flow direction of the coolant (80) in the coolant channel (90).

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