COOLING ELEMENT AND METHOD FOR MANUFACTURING A COOLING ELEMENT

Abstract

A cooling element for cooling an electrical device is provided. The cooling element comprises a first plate with a first surface, a second plate with a first surface and a second surface opposite the first surface, the second surface being configured to be attached to the electrical device, the first plate and the second plate being attached to each other with their respective first surfaces facing each other, a first structure being arranged between the first plate and the second plate such that a channel is formed between the first plate and the second plate, and two fluid connectors being in fluid exchange with the channel to connect the channel to a cooling circuit.

Description

TECHNICAL AREA The present disclosure relates to a cooling element for cooling an electrical device using a liquid and a method for manufacturing such a cooling element. BACKGROUND Many electrical devices, especially power semiconductor devices, generate heat during operation. This can cause the devices to heat up, and if the heat is not dissipated by adequate cooling, the devices can reach a critical temperature at which they could fail or even catch fire. This problem becomes more serious with increasing power densities, as the thermal mass and / or space available for cooling the device decreases. Conventional electrical devices are cooled by the convection of a cooling fluid, such as air. Attaching a heat sink to the device increases the surface area for heat transfer from the device to the cooling fluid. Other conventional approaches use a liquid as the cooling medium, which can have the advantage that a liquid can absorb significantly more heat than a gaseous cooling fluid. Thus, a liquid coolant can dissipate more heat from the device. Conventional cooling solutions that use liquid as the cooling medium are complex to set up properly, including the development of custom-designed heat sinks and sealed cooling channels and pipe connections to allow the liquid to be pumped through the cooling circuit. Furthermore, conventional solutions are expensive, require significant space, and are not easily adaptable if an electrical system layout changes. DE 10 2017 217 537 A1 discloses an electronic device comprising: a power module with a circuit carrier on which a circuit component is arranged; a cooling structure; and an intermediate structure arranged between the circuit carrier and the cooling structure, wherein the cooling structure is made of a first metal material and the intermediate structure is made of a second metal material with a higher thermal conductivity than that of the first metal material. DE 10 2016 125 338 A1 discloses a system for cooling a support substrate intended for electrical components, wherein the support substrate has a component side and a cooling side opposite the component side with a cooling structure, wherein the system comprises a shell element, wherein the shell element is designed such that the shell element attached to the support substrate together with the cooling side of the support substrate forms a fluid channel, characterized in that the shell element is designed such that the fluid flowing in the main flow direction is deflected for introduction into the cooling structure. Other conventional devices are known from WO 2018 / 001525 A1, EP 3147940 A1 and AT 515440 A1. It is an object of the present disclosure to provide an improved cooling element for cooling an electrical device using a liquid and a corresponding method for manufacturing such a cooling element. SUMMARY This problem is solved by a cooling element and a method for manufacturing a cooling element having the features according to the attached independent claims. Further advantageous embodiments are specified in the dependent claims. The expert will recognize additional features and advantages upon reading the following detailed description and upon examining the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure is illustrated by way of example and without limitation in the figures of the accompanying drawings, in which the same reference numerals refer to similar or identical elements. The elements of the drawings are not necessarily to scale relative to one another. The features of the various examples shown may be combined, provided they are not mutually exclusive. Fig. 1 shows a vertical cross-section of a first example of a cooling element. Fig. 2A and Fig. 2B each show a horizontal section of a corresponding second example of a cooling element. Fig. 3 shows an isometric view of a third example of a cooling element. Fig. 4 shows another isometric view of the third example of a cooling element. Fig. 5 shows a vertical cross-section of a fourth example of a cooling element.Figure 6 shows a vertical cross-section of a fifth example of a cooling element. Figure 7 shows a top view of a sixth example of a cooling element. Figure 8 shows a top view of a first example plate of a cooling element before processing to provide a flow path. Figure 9 shows a top view of the first example plate of a cooling element after processing to provide a flow path. Figure 10 shows a schematic cross-section of a multilayer structure. Figure 11 shows a schematic block diagram of a first example method for manufacturing a cooling element. Figure 12 shows a schematic block diagram of a second example method for manufacturing a cooling element. Figure 13 shows a schematic block diagram of a system comprising a cooling circuit and a cooling element. DETAILED DESCRIPTION The examples described herein provide a cooling element designed for liquid cooling of a mounted electrical device, such as transformer coils, resistors, capacitors, semiconductor devices, or the like. For this purpose, the cooling element provides a structure incorporating a channel for the coolant and features fluid connectors in exchange with the channel, enabling connection of the channel to a cooling circuit. By pumping coolant through the channel, heat generated by the electrical device mounted to the cooling element can be dissipated more effectively than with air cooling, allowing the device to operate under higher power dissipation conditions without risk of thermal damage. The described example cooling elements can be integrated into the cooling circuit of a larger electrical system, such as power converters and inverters, and used to cool specific electrical devices within the system. Integration into the cooling circuit might involve connecting or attaching the cooling element to the circuit using suitable tubing that is inserted into the provided fluid connectors on the cooling element. When a pressure differential exists between the fluid connectors, coolant flows through the cooling channel. The cooling rate can depend on factors such as the coolant flow rate, the temperature difference between the coolant and the electrical device, and the thermal impedance of the heat conduction path between the electrical device and the channel. Other factors may also influence the cooling rate. Fig. 1 shows a cross-section of a first implementation of a cooling element 100 for cooling an electrical device according to the present disclosure. The cooling element 100 comprises a first plate 110 with a first surface 110A, a second plate 120 with a first surface 120A and a second surface 120B opposite the first surface 120A, the second surface 120B being configured to be attached to the electrical device. The second plate 120 can include at least one cooling area (not shown) on the second surface 120B, the cooling area being configured to transfer heat from an electrical device in thermal contact with the cooling area to the second surface 120B, so that a cooling fluid flowing over the second surface 120B during operation of the cooling element 100 can absorb heat from the electrical device and thus dissipate it.The first plate 110 and the second plate 120 are attached to each other with their respective first surfaces 110A and 120A facing each other. A first structure 112 is arranged between the first plate 110 and the second plate 120 such that a channel 130 is formed between the first plate 110 and the second plate 120. For example, the channel 130 is formed in such a way that it is leak-tight. Leak-tight here means that no fluid can escape from the channel 130 into an area outside the cooling element 100. However, it may be possible for some of the cooling fluid to penetrate from a first section of the channel 130 into a second, remote section of the channel 130 without flowing along the channel 130. In other words, a small portion of the coolant can pass between the first plate 110, the first structure 112 and the second plate 120 outside the channel 130, without, however, escaping from the cooling element 100.This portion can be, for example, less than 1% or less than 10% of the fluid flowing through the corresponding channel 130. At a lateral end of the cooling element 100, the first structure 112 is configured to seal the cooling element 100 and prevent any fluid flow outside of specially designed connecting elements. All the cooling fluid is supplied to and discharged from the cooling element 100 via fluid connectors 140. For example, the channel 130 can be defined by the first structure 112. Two fluid connectors 140 (see, for example, Fig. 2A, Fig. 2B) are provided in a fluid exchange with the channel 130, so that the channel 130 can be connected to a cooling circuit 510 (see Fig. 13). “In a fluid exchange” can mean that a fluid can be supplied to or discharged from the channel via the fluid connectors. Fig. 13 shows a schematic block diagram of a system 500 comprising a cooling circuit 510 and a cooling element 100, for example, the cooling element shown in one of Figs. 1 to 7. The cooling circuit 510 may include at least one pump, radiator, fan, compressor, thermoelectric element, or the like. The cooling circuit 510 is configured to circulate coolant, for example, through the channel 130 of the connected cooling element 100. Furthermore, the cooling circuit 510 is configured to cool coolant coming from the cooling element 100 at an elevated temperature. For example, the cooling circuit 510 and the cooling element are connected via hose or pipe connections. Here, hose 502 is used to supply coolant to the cooling element, and hose 504 is used to return the coolant after it has flowed through the cooling element 100.In other configurations, more than one cooling element 100 may be present. In this case, the cooling elements may be connected in series (e.g., chained) with respect to the cooling circuit 510 and / or in parallel. Fig. 2A shows a top view of a second example of a cooling element 100, with the second plate 120 located on top of the cooling element 100 in this view. The cooling element 100 of Fig. 2A can have the same features as the cooling element described with reference to Fig. 1. In Fig. 2A, the dashed lines are used to represent the first structure 112, which is arranged below the second plate 120. Based on the geometry of the first structure 112, the channel 130 is formed. In this example, the channel 130 has a meandering shape. Two connectors 140 are attached to the cooling element 100 to provide access to the channel 130 from an external cooling circuit (not shown). Each of the connectors 140 can be provided in the form of a plug or a socket.The connectors can be specifically designed to be inserted into a corresponding socket or to accept a corresponding plug to provide a tight and sealed connection between the channel 130 and the external cooling circuit. In this example, the connectors 140 are arranged in a side wall of the cooling element 100 (e.g., perpendicular to a plane of extension of the first plate 110 and the second plate 120), but other arrangements are also possible. Furthermore, more than two connectors 140 can be provided to offer access to the channel 130. The different connectors 140 can also have different shapes and / or sizes. In one or more implementations, the first structure 112 can have a geometry such that more than one channel 130, e.g., two channels, are formed (not shown). The two or more channels can be separate from each other. In this case, a respective set of at least two connectors 140 (e.g., at least one inlet and one outlet) can be provided for each of a plurality of channels. Alternatively or additionally, the multiple channels can share a common section. Furthermore, the two connectors 140 can be in fluid exchange with at least two channels of the multiple channels 130. Such an example is shown in Fig. 2B. Here, the two connectors 140 are connected to a respective common channel section 131, which provides access to two separate channels 130. The two separate channels 130 are thus in a parallel arrangement with respect to the fluid flow.Within one or more channels 130, optional flow-limiting elements 132 may be provided, which are configured to control a flow rate in the respective channel 130. For example, the flow-limiting elements 132 may be formed at one or both transitions from the common channel section 131 to the respective channel 130, or they may be formed within the channel 130. In one or more implementations of the cooling element 100, the first structure 112 is integral with the first plate 110 and extends from the first surface 110A of the first plate 110, as shown in Fig. 1. Here, "integral" means that the first plate 110 and the first structure 112 form a monolithic body. For example, the first plate 110, including the first structure 112, can be formed by injection molding and / or using additive manufacturing processes (e.g., 3D printing) and / or using machining processes (e.g., milling, drilling, turning, machining, cutting, etc.). Therefore, joining the second plate 120 to the first structure 112 can also be understood as joining the second plate 120 to the first plate 110. In one or more implementations of the cooling element 100, the first plate 110 and the second plate 120 extend over the first structure 112 and are connected directly at the edge of the cooling element 100 without the first structure 112 intervening. For example, the first structure 112 is slightly smaller (e.g., in the range of several millimeters to several centimeters on each lateral edge) than both the first plate 110 and the second plate 120. At least one of the first plate 110 and the second plate 120 may be bent toward the other plate to provide a direct contact line at a circumferential edge of the cooling element 100. This can have the advantage that only the circumferential edge of the cooling element needs to be implemented in a leak-tight manner, while the connection in other fastening areas (e.g.,where the first structure 112A is provided to form channel 130) can be implemented in a simpler and therefore more cost-effective way. In one or more implementations, the first plate 110 and the first structure 112 can be provided as separate elements and joined, for example, by welding, gluing, or forming. For example, the dashed line 111 in Fig. 1 shows the connection between the first plate 110 and the first structure 112. In one or more implementations of the cooling element 100, the first plate 110 and the second plate 120 are joined together, for example, by welding, gluing or forming. In one or more implementations of the cooling element 100, a weld between the first plate 110 and the second plate 120 is formed exclusively from material of the first plate 110 and / or the second plate 120. In these implementations, welding is performed without providing any additional material, such as a filler material or a welding filler. In other words, it is the material of at least one of the first plate 110 and the second plate 120 that is subjected to the welding process. It should be noted that this does not preclude the use of a welding aid, such as a shielding gas, which does not become part of the weld during the welding process. Here, for example, at least one of the first plate 110 and the second plate 120 comprises a weldable material. The weldable material may be a plastic material, in particular a thermoplastic material, and / or a metal material. The welding process can involve heating the assembly of the first plate 110 and the second plate 120, including the first structure 112 between them, and applying pressure so that the plates are pressed together. The heating can be global (e.g., including the entire assembly) and / or local (e.g., only at selected contact surfaces between the plates). In one or more implementations of the cooling element 100, the first plate 110 and / or the second plate 120 comprises a functionalized surface area 115, which is specifically functionalized to provide a mounting area for attaching the other of the first plate 110 or the second plate 120. The functionalized surface area 115 can be functionalized by chemical, physical, and / or mechanical processes. Chemical functionalization can involve surface treatment using chemical agents that result in a change in the surface structure and / or coating the surface area with a functional agent, such as a polymer. Physical functionalization can involve surface treatment using a plasma and / or irradiating the surface with electromagnetic radiation (e.g., a laser beam) or particles (e.g., a microsphere).The functionalization process may involve electrons or sputtering with atoms / molecules. Mechanical functionalization may include sandblasting, grinding, polishing, or similar processes. Naturally, the various functionalization processes can be combined. Functionalization can be applied selectively to the respective surface to provide the functionalized surface area 115. For example, the functionalized surface area 115 may be limited to contact surfaces between the first plate 110 and the second plate 120. Functionalization may be applied only to the first plate 110, only to the second plate 120, or to both. Furthermore, functionalization may be applied to a first area on the first plate 110 and to a second area on the second plate 120.The functionalization of the first disk 110 may differ from the functionalization of the second disk 120. In one or more implementations of the cooling element 100, at least one of the first plate 110 and the second plate 120 is substantially made of a plastic material or a composite material and / or formed by an injection molding process. Here, "substantially made of" means that the body of the respective plate is formed from the material, but the respective plate may include other elements, such as the functionalized surface area 115, and / or elements that can be used to attach the respective plate or cooling element to other elements, and / or elements that can provide mechanical support or the like. For example, a bushing or pin may be provided made of a different material than the rest of the respective plate. In one or more implementations of the cooling element 100, the second plate 120 is formed from a multilayer substrate, in particular an insulated metal substrate (IMS), a direct copper bonded (DCB) substrate, a hard-soldered active metal substrate (AMB) or a printed circuit board (PCB). Here, multilayer substrate means that the substrate contains a multitude of layers. The different layers can be made of the same material or of different materials. For example, the multilayer substrate can be a laminate consisting of many layers. In one or more implementations of the cooling element 100, the second plate 120 comprises a metal layer 122 (see Fig. 5) on its second surface 120B, which is configured to conduct an electrical signal. The electrical signal may include at least one control signal, a measurement signal, or a load current. In one example, the metal layer 122 is configured to conduct a load current controlled by the electrical device 200 (see Fig. 4 or Fig. 7). In this example, the electrical device 200 can be implemented as a power semiconductor transistor controlled by a control signal provided by a controller to supply a load current to an electrical load. The metal layer 122 can be electrically connected to a positive or negative power supply node, for example, a DC+ or DC- bus. In one or more implementations, the metal layer 122 is a structured layer with a multitude of sections. The different sections can be separated from one another. For example, the different sections can be electrically isolated from each other. In this case, the different sections can be used to conduct different electrical signals. In one example, a first section can be used to conduct a load current, and a second section can be used to conduct a control signal or the like. In another example, a first section can be used to conduct a first load current, and a second section can be used to conduct a second load current. In yet another example, the structured metal layer can include one or more conductive traces that can be used to conduct one or more electrical signals.In further implementations, the different sections can be electrically coupled to each other, with the coupling being implemented in such a way that a specific impedance is provided between the different sections. For example, the coupling can provide a specific resistance value, a specific capacitive coupling, or a specific magnetic coupling. Fig. 3 shows an isometric view of a third example of a cooling element 100. In this example, the second surface 120B of the second plate 120 includes a metal layer 122 structured into four separate sections. Each of the sections of the metal layer 122 can be configured to conduct a load current or other electrical signal. Here, the four sections of the metal layer 122 are configured to serve as mounting areas for attaching a respective electrical device 200 to be cooled. In particular, as shown in Fig. 4, the electrical devices 200 are implemented as power semiconductor switches in a package, such as a TO-247 package. This is only one example, and semiconductor devices enclosed in other packages, especially packages conventionally used in industry, can be used.The power semiconductor devices 200 can be soldered or sintered with their back side to the respective section of the metal layer 122 provided on the second surface 120B of the second plate 120. It should be noted that other means can also be used to fasten the power semiconductor devices 200, such as screws or clamps or the like. Fig. 5 shows a cross-section of a fourth example of a cooling element 100. The cooling element 100 of Fig. 5 can have the same features as described with reference to Fig. 1. In addition, the first structure 112 includes additional elements 114 extending from the first surface 110A to positions where the channel 130 is formed when the second plate 120 is attached. The additional elements 114 can be selectively provided at chosen positions and can act as turbulators, causing turbulence in the coolant flowing through the channel 130. This can increase the heat transfer to the coolant. Furthermore, the second plate 120 includes the metal layer 122 on its second surface 120B. In this example, the metal layer 122 includes three sections, each section being used to attach the electrical device 200 (e.g., a power supply).a power semiconductor or other electrical device that requires cooling). It should be noted that in this example, the sections of the structured metal layer 122 are arranged in the channel 130 according to the turbulators 114. The structured metal layer 122 can also have a relatively high thermal conductivity (e.g., higher than that of the material of the second plate 120), so that heat transfer from the electrical device 200 to the cooling fluid flowing in the channel 130 can be improved. In one or more implementations of the cooling element 100, the second plate 120 includes an insulating material designed to provide electrical insulation between the first surface 120A and the second surface 120B of the second plate 120. This has the advantage that a voltage that can be applied to a metal layer 122 on the second surface 120B of the second plate 120 is isolated from the coolant and thus also from the cooling circuit. For example, the insulating material can be a polymer, plastic, fiber, ceramic, or glass material. In one or more implementations, the insulating material is formed as a layer of the second plate 120. In one or more implementations, an electrical device can be arranged on one of the first surface 120A of the second plate 120 and / or on the second surface 120B of the second plate 120 and / or be integrated into the second plate 120. For example, the electrical device can be a resistor, a capacitor, an inductor, a diode, a transistor, a transformer, an integrated electronic circuit, or any type of sensing element. In one example, the electrical device can be a temperature sensor arranged on the first surface 120A of the second plate 120 and configured to provide a temperature signal indicating the temperature of the coolant in the channel 130. For this purpose, the temperature sensor can be arranged on the second surface 120A to extend into the channel 130. The temperature sensor can be connected by conductive traces (e.g.,The electrical device can be connected to terminals on the second surface 120B via conductors extending through the body of the second plate 120. In one example, the electrical device is integrated into the second plate 120, meaning it is located between the first surface 120A and the second surface 120B. The electrical device can be connected to terminals on the second surface 120B via conductors extending through the body of the second plate 120. Fig. 6 shows a cross-section of a fifth example of a cooling element 100. In this implementation, a third plate 125 has a first surface 125A and a second surface 125B opposite the first surface 125A, the second surface 125B being configured to be attached to the electrical device 200. The third plate 125 is attached to the first plate 110 opposite the second plate 120, with a second structure 112B arranged between the first plate 110 and the third plate 125 such that a further channel 132 is provided between the first plate 110 and the third plate 125. In this example, the first plate 110 can have the first structure 112A on its first surface 110A and the second structure 112B on its second surface 110B. The first structure 112A and / or the second structure 112B can be integral with the first plate 110. The further channel 132 is defined by the second structure 112B. Although the channel 130 and the further channel 132 have an identical shape in this representation, this is not required. Instead, the channel 130 and the further channel 132 can have different shapes and / or geometries and can be specifically adapted to the respective side of the cooling element 100 based on the electrical device 200 to be cooled. The first plate 110 and / or the first structure 112A and / or the second structure 112B can be produced in the same and / or a single manufacturing process.For example, the first plate 110, which includes the first structure 110A and the second structure 112B, can be formed in a single forming process. Alternatively, the first structure 112A and / or the second structure 112B can be formed as separate elements and then joined to the first plate 110. Fig. 7 shows a top view of a sixth example of a cooling element 100. In this example, the cooling element 100 can have a structure similar to that shown in Fig. 6, wherein the first plate 110, the second plate 120, and the third plate 125 form a sandwich structure with a channel 130 and a further channel 132 for cooling attached electrical devices 200. In this example, the electrical devices 200 are power semiconductor transistors, but other implementations are also possible. In this example, the respective second surface 120B, 125B of the second plate 120 and the third plate 125 includes a metal layer 122. As schematically indicated, the metal layer 122 can be connected to a bus voltage (denoted as "V" in Fig. 7) during the operation of the power semiconductor transistors 200.For example, the power semiconductor transistors 200 can be attached to the cooling element 100, with their drain contact electrically connected to the metal layer 122. In this case, the second plate 120 and the third plate 125 can preferably include an electrically insulating layer to isolate the metal layer 122 from the coolant. Thus, the metal layer 122 forms a load node for each of the power semiconductor transistors 200 and is configured to conduct a load current. This can simplify the electrical layout of a system using the power semiconductor transistors 200. As mentioned above, the metal layer 122 can also be structured and can be used to conduct additional and / or other electrical signals. It is noted that the number of devices 200 is variable, meaning that more than eight or fewer than eight devices may be attached to the cooling element 100, and the number of devices 200 attached to the second plate 120 may differ from the number of devices 200 attached to the third plate 125. Furthermore, different types or varieties of electrical devices 200 may be attached to each side of the cooling element 100. For example, different power semiconductor devices (e.g., transistors and / or diodes with different voltage classes and / or different technologies) and / or different types of electrical devices (e.g., inductors, capacitors, resistors, etc.) may be attached to each side of the cooling element 100. In one or more implementations of the cooling element 100, two additional fluid connectors (not shown) are provided in a fluid exchange with the additional channel 132 to connect the additional channel 132 to the cooling circuit. Thus, coolant can be supplied to the additional channel 132 separately from coolant supplied to channel 130. In one or more implementations of the cooling element 100, the two fluid connectors 140 are in fluid exchange with the further channel 132. Thus, coolant can be supplied to both the channel 130 and the further channel 132 using only two fluid connectors 140. In one or more implementations of the cooling element 100, channel 130 and the additional channel 132 are in fluid exchange with each other. In further implementations, channel 130 and the additional channel 132 form a common channel in at least one section. This means, for example, that channel 130 and the other channel 132 may have a common liquid distribution section (for distributing coolant supplied through connector 140 to cooling surfaces of the respective channel 130, 132) and / or a common liquid drain section (for collecting the coolant after it has passed through the cooling surfaces of the respective channel 130, 132 and draining it via the other connector 140). In one or more implementations of the cooling element 100, the second plate 120 and / or the third plate 125 (if present) comprise secondary structures extending from their first surface 120A, 125A into the channel 130, 132 (not shown). For example, the secondary structures may include elements for increasing the surface area in contact with the cooling fluid and / or turbulator structures for improving heat transfer from the second plate 120 or the third plate 125 to the cooling fluid flowing through the channel 130 or the further channel 132. In one or more implementations of the cooling element 100, the first plate 110 includes additional elements extending from the first surface 110A and / or from the second surface 120B, which act as turbulators to improve heat transfer from the second plate 120 or the third plate 125 to the cooling fluid flowing through the channel 130 or the further channel 132. In one or more implementations of the cooling element 100, the first structure 112 comprises a plurality of base cell structures 113 arranged in a lattice on the first surface 110A of the first plate 110. An example of such a first plate 110 is shown in Fig. 8. In this example, the first structure 112 comprises a 5 × 10 basal cell structures 113 grid. The first plate, as shown in Fig. 8, can be used as a starting point to define a channel 130, for example, by selectively removing walls between adjacent basal cell structures 113. It is noted that other geometries of the basal cell structures are possible, such as triangular, rectangular, circular, hexagonal, or any other suitable basic geometric shape that can be used to fill the first surface of the first plate 110. In one or more implementations of the cooling element 100, the first surface 110A of the first plate 110 is covered by a periodic arrangement of the base cell structures 113, such that the first surface 110A is filled by cavities separated by partition walls, the channel 130 being formed by adjacent cavities with the partition walls removed between them. An example of such a first plate 110 is shown in Fig. 9. A flow path 116 is formed by connecting cavities of the individual base cell structures (e.g., by selectively removing a number of partitions between adjacent cavities so that the respective cavities are connected to each other). In addition, fluid connectors 140 are attached to the first plate 110 at the two ends of the flow path 116. If the flow path 116 is formed by removing the partition structures, a portion of the respective partition structures may be intentionally left in place to provide a flow-regulating and / or turbulator structure. When the second plate or a film is attached on top of the first plate 110, the flow path 116 forms a channel 130. In some embodiments, two or more flow paths 116 can be formed in the first plate 110 (not shown). The two or more flow paths 116 can be connected by separate pairs of fluid connectors 140. Two or more flow paths can be in fluid exchange with an identical pair of fluid connectors 140, for example, via a common section of the flow path. Part of the respective partition structures can be intentionally left in place to provide a flow-limiting element, while in other parts, for example, in the common section, more partition structures can be removed to provide a larger cross-section for the cooling fluid. The first plate 110, as shown in Fig. 8, can be considered a template that can be used to easily define a channel for the cooling fluid. In particular, if the required number of separate cooling elements 100 for setting up a cooling system for a specific electrical system is small, the first plate 110 can be an economical method that allows for free adaptation of the channel geometry and does not require much material. For example, due to the base cell structure 113, which can have a material filling ratio (e.g., the portion of the volume of a base cell structure that is filled with material) of between 10% and 50%, the first plate 110 requires much less material to be manufactured compared to a solid plate. In one or more implementations of the cooling element 100, at least one cavity is not connected to the channel 130 and is configured to accommodate a fastening element for attaching the cooling element 100 to the electrical device 200. Alternatively or additionally, the at least one cavity can be configured to accommodate a fastening element for attaching the cooling element 100 to an external mounting structure, such as a frame or a housing. This is shown in Fig. 9, where a total of six cavities are not part of the flow path 116 and therefore not part of the channel 130. Fig. 10 shows a schematic cross-section of a multilayer structure that can be used, for example, as a second plate 120 or a third plate 125 in a cooling element, as described above. In this example, the multilayer structure 120 comprises a core element 121, a structured metal layer 122 on one side, and an insulating material layer 123 on the other side. The core element 121 can be used, in particular, to provide the structure with mechanical integrity and stability. Preferably, the core element 121 has good thermal conductivity properties. For example, the core element 121 has a thermal conductivity coefficient of more than 10 W / (m·K). The structured metal layer 122 can be used to mount electrical devices to be cooled and to conduct an electrical signal, as described above. The multilayer structure 120 can, for example, be a laminate. According to a second aspect of the present disclosure, a cooling element 100 for cooling an electrical device 200 comprises a plate 110 with a first surface 110A and a first structure 112 formed thereon, a film 120 with a first surface and a second surface opposite the first surface, the second surface being configured to be attached to the electrical device 200, the plate 110 and the film 120 being attached to one another with their respective first surfaces facing each other, such that the first structure 112 is arranged between the plate 110 and the film 120 in such a way that a channel 130 is formed between the plate 110 and the film 120, the channel 130 being defined by the first structure 112, and two fluid connectors 140 being attached to the plate 110 and being in fluid exchange with the channel 130 to connect the cooling element 100 to a cooling circuit. For example, the cooling element shown in Fig. 9 can be implemented as described using a film instead of a second plate 120. This can offer the advantage of simple manufacturing as well as further cost reduction. According to a third aspect, a method 300 for manufacturing a cooling element 100 for cooling an electrical device 200 is proposed. Method 300 is illustrated by way of example in Fig. 11 and comprises the following steps. In a first step S11, a plate 110 is provided, having a first surface and a second surface opposite the first surface, and comprising a first structure 112 extending from the first surface. The first structure 112 comprises a periodic arrangement of a base cell structure 113, each base cell structure comprising at least one cavity surrounded by walls, such that a plurality of cavities separated by partition walls are formed on the first surface 112. For example, the plate 110 can have the shape shown in Fig. 8. The plate 110 can be formed, for example, by injection molding from a suitable material.In a second step S12, at least one partition wall is selectively removed so that the adjacent cavities are connected and form a flow path 116. The removal can be carried out by any suitable method, such as milling, machining, drilling, turning, melting, etc. In a third step S13, a cover element with a first surface and a second surface facing the first surface is provided. The cover element can be, for example, a film or a solid plate. In a fourth step S14, the cover element is attached to the plate 110 so that their respective first surfaces face each other and the first structure 112 is arranged between the plate 110 and the cover element, and so that the flow path 116 forms a channel 130 designed to carry a coolant flow.Fastening can be achieved through a thermal treatment, such as lamination. In a fifth step S15, at least two connectors 140 are provided so that they are in fluid exchange with the channel 130 to connect the channel 130 to a cooling circuit. It is noted that the connectors 140 can be provided in a simple form by simply drilling a hole through a side wall of the cooling element 100. According to a further aspect of the present disclosure, a cooling element 100 for cooling at least two power semiconductor devices 200 comprises a first plate 120 configured to be attached to a first power semiconductor device 200, a second plate 125 configured to be attached to a second power semiconductor device 200, an intermediate element 110 comprising at least one frame and at least one fluid-carrying structure, and a fluid inlet 140 and a fluid outlet 140 arranged in the frame, wherein the first plate 120 is attached to a first side of the intermediate element 110 and the second plate 125 is attached to a second side of the intermediate element 110, such that a cavity is formed between the first plate 120, the second plate 125 and the frame, the fluid-carrying structure being arranged in the cavity and forming a channel 130.which is in fluid exchange with the fluid inlet 140 and the fluid outlet 140, so that a cooling fluid can flow through the channel 130. According to another aspect of the present disclosure, a method 400 for manufacturing a cooling element 100 for cooling an electrical device 200 comprises the following steps. In a first step S21, a first plate 110 with a first surface 110A is provided. In a second step S22, a second plate 120 with a first surface 120A and a second surface 120B opposite the first surface 120A is provided. The second surface 120B is configured to be attached to the electrical device 200. In a third step S23, a first structure 112 is provided which is configured to define a flow path 116. The first structure 112 can be a separate element or can be provided on the first surface 110A of the first plate 110, for example by removing material or by depositing material.In a fourth step S24, the first plate 110 and the second plate 120 are connected such that their respective first surfaces 110A, 120A face each other, the first structure 112 being arranged between the first plate 110 and the second plate 120 such that a channel 130 is formed between the first plate 110 and the second plate 120, as defined by the flow path 116. In a fifth step, at least two connectors 140 are provided, which are in fluid exchange with the channel 130 in order to connect the channel 130 to a cooling circuit. Although specific examples have been illustrated and described here, the person skilled in the art will recognize that a multitude of alternative and / or equivalent implementations can replace the specific examples shown and described without altering the scope of protection of the present invention. This application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, it is intended that this invention is limited only by the claims and their equivalents. It should be noted that the methods and devices, including their preferred embodiments, as set forth in this document, can be used alone or in combination with the other methods and devices disclosed herein. Furthermore, the features described in connection with a device are also applicable to a corresponding method, and vice versa. Moreover, all aspects of the methods and devices described in this document can be combined in any way. In particular, the features of the claims can be combined with one another in any manner. It should be noted that the description and drawings merely illustrate the principles of the proposed methods and systems. A person skilled in the art will be able to implement various arrangements which, although not explicitly described or shown here, embody the principles of the invention and are included in its meaning and scope of protection. Furthermore, all examples and embodiments presented in this document are expressly intended primarily for illustrative purposes only, to assist the reader in understanding the principles of the proposed methods and systems. Moreover, all statements herein that provide principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to include equivalents thereof.

Claims

Cooling element (100) for cooling an electrical device (200), comprising: a first plate (110) with a first surface (110A), a second plate (120) with a first surface and a second surface (120B) opposite the first surface, wherein the second surface (120B) is configured to be attached to the electrical device (200), the first plate (110) and the second plate (120) are attached to one another with their respective first surfaces facing each other, wherein a first structure (112) is arranged between the first plate (110) and the second plate (120) such that a channel (130) is formed between the first plate and the second plate, two fluid connectors (140) which are in fluid exchange with the channel (130) to connect the channel (130) to a cooling circuit, wherein: the first structure (112) comprises a plurality of base cell structures (113),wherein each base cell structure (113) comprises a cavity with surrounding walls such that the first surface (110A) is filled by cavities separated by partition walls, wherein the channel (130) is formed by adjacent cavities between which the partition walls are removed, and at least one cavity is not connected to the channel (130) and is configured to receive a fastening element for attaching the cooling element (100) to the electrical device (200) and / or to an external fastening structure. Cooling element according to claim 1, wherein the first structure (112) is integral with the first plate (110) and extends from the first surface (110A) of the first plate (110). Cooling element according to claim 1 or 2, wherein the first plate (110) and the second plate (120) are joined together by welding. Cooling element according to the preceding claim, wherein the weld seam is formed exclusively from material of the first plate (110) and / or the second plate (120). Cooling element according to one of the preceding claims, wherein the first plate (110) and / or the second plate (120) comprises a functionalized surface area (115) which is specifically functionalized to provide a mounting area for mounting the other of the first plate or the second plate. Cooling element according to one of the preceding claims, wherein at least one of the first plate (110) and the second plate (120) is substantially made of a plastic material or a composite material and / or is formed in an injection molding process. Cooling element according to one of the preceding claims, wherein the second plate (120) is formed from an insulated metal substrate or a directly copper-bonded substrate, a hard-soldered active metal substrate or a printed circuit board material. Cooling element according to the preceding claim, wherein the second plate (120) comprises a metal layer on its second surface (120B) which is configured to conduct an electrical signal. Cooling element according to the preceding claim, wherein the metal layer is configured to conduct a load current controlled by the electrical device (200). Cooling element according to one of the preceding claims, wherein the second plate (120) comprises an insulating material configured to provide electrical insulation between the first surface (120A) and the second surface (120B) of the second plate (120). Cooling element according to one of the preceding claims, further comprising: a third plate (125) with a first surface and a second surface opposite the first surface, wherein the second surface is configured to be attached to the electrical device (200), the third plate (125) is attached to the first plate (110) opposite the second plate (120), wherein a second structure is arranged between the first plate (110) and the third plate (125) such that a further channel (132) is formed between the first plate (110) and the third plate (125). Cooling element according to the preceding claim, further comprising at least one further fluid connector which is in fluid exchange with the further channel (132) in order to connect the further channel (132) to the cooling circuit. Cooling element according to claim 12, wherein the two liquid connectors are in a liquid exchange with the further channel (132). Cooling element according to the preceding claim, wherein the channel (130) and the further channel (132) are in fluid exchange with each other and / or form a common channel in at least one section. Cooling element according to one of the preceding claims, wherein the second plate (120) comprises second structures extending from its first surface into the channel. Cooling element according to one of the preceding claims, wherein the plurality of base cell structures (113) are arranged in a grid on the first surface (110A) of the first plate (110). Cooling element according to the preceding claim, wherein the first surface (110A) of the first plate (110) is covered by a periodic arrangement of the base cell structures (113). Cooling element according to one of the preceding claims, further comprising: at least one power semiconductor device (200) attached to the second surface (120B) of the second plate (120). Cooling element according to one of claims 12 to 15, further comprising: at least a first power semiconductor device (200) attached to the second surface (120B) of the second plate (120), and at least a second power semiconductor device (200) attached to the second surface (125B) of the third plate (125). Cooling element according to one of claims 18 or 19, wherein the respective of the at least one power semiconductor device (200), the at least first and / or the at least second power semiconductor device is attached to the second plate (120) or the third plate (125) by means of soldering and / or sintering. Cooling element according to one of claims 18 or 19, wherein the respective of the at least one, the at least first and / or the at least second power semiconductor device is provided in a standard semiconductor package, in particular TO-247. A method (300) for manufacturing a cooling element (100) for cooling an electrical device (200), comprising the steps: providing (S11) a plate (110) having a first surface (110A) and a second surface opposite the first surface and comprising a first structure (112) extending from the first surface, wherein the first structure (112) comprises a plurality of base cell structures (113), each base cell structure (113) comprising at least one cavity surrounded by walls, such that a plurality of cavities separated by partition walls are formed on the first surface (110A); selectively removing (S12) at least one partition wall, such that the adjacent cavities are connected and form a flow path (116), wherein the selective removal comprises leaving the walls of at least one cavity untouched.so that the at least one cavity is not connected to the adjacent cavities and is configured to receive a fastening element for attaching the cooling element (100) to the electrical device (200) and / or to an external mounting structure, providing (S13) a cover element with a first surface and a second surface opposite the first surface, attaching (S14) the cover element to the plate such that their respective first surfaces face each other and the first structure (112) is arranged between the plate (110) and the cover element, and such that the flow path forms a channel (130) configured to carry a cooling fluid, and providing (S15) at least two connectors (140) that are in fluid exchange with the channel (130) to connect the channel (130) to a cooling circuit.

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