Method for connecting a heat generating component to a cooling device

Abstract

In order to provide a low-cost method for connecting a heating element to a cooling device and reducing production cycle, a method (100) for connecting a heating element (10) to a cooling device (11) is proposed, wherein a connecting material (12), preferably a welding material or sintering paste, is arranged between the heating element (10) and the cooling device (11), wherein heat input to the connecting material (12) is achieved by the operation of the heating element (10), and / or wherein the cooling device (11) has a cooling structure (16) for guiding a heat transfer medium through, wherein heat input to the connecting material (12) is achieved by injecting heated fluid into the cooling structure (16) of the cooling device (11).

Description

Technical Field

[0001] The present invention relates to a method for connecting a heating element (or a heat-generating element) to a cooling device, wherein a connecting material, preferably a welding material or a sintering paste, is arranged between the heating element and the cooling device. Background Technology

[0002] To connect components, the prior art primarily uses soft soldering. In so-called reflow soldering, the printed circuit board (PCB) is connected to the component by first applying soft solder paste to the PCB in the first step before mounting. In the next step, the component is mounted. The mounted PCB is then heated to melt the solder contained in the solder paste.

[0003] In vapor phase welding, also known as thermal condensation welding, the heat released during the phase change of the heat transfer medium from a gaseous state to a liquid state is used to heat the component. Here, the condensation of the heat transfer medium occurs on the surface of the welded item until the entire component reaches the temperature of the gaseous heat transfer medium.

[0004] The equipment used in reflow soldering requires significant space. Furthermore, especially for larger or thick-walled components, the poor heat input results in longer process times. Additionally, vapor phase welding incurs higher fluid costs.

[0005] A method for connecting a printed circuit board to a component is known from US 6,503,336 B1, wherein a heated fluid is introduced between the component and the printed circuit board via a nozzle. The heated fluid melts solder balls disposed thereon.

[0006] DE 41 03 098 C1 discloses a method for soldering components in electronic devices or soldering metals in mechanical manufacturing. By wetting the solder joint with a heated liquid, at least part of the heat required for the soldering process is transferred to the solder joint.

[0007] DE 196 176 18 A1 discloses a method for desoldering. A method and apparatus for making electronic components, wherein the welded portion of the component is immersed in a hot fluid in the form of steam or liquid, so that the welded portion melts.

[0008] Especially when joining larger components using soft soldering, known methods are disadvantageous. Due to the size or thickness of the components, the heated fluid cannot usually be directly conducted to the weld area. If the entire component is heated during reflow soldering, a correspondingly large amount of heat must be applied to larger components, making reflow soldering technically inefficient. Furthermore, it typically requires a long process time.

[0009] The aforementioned problems arise particularly when connecting the power module to a cooling system. Such power modules, connected to cooling systems, are primarily used in electric transportation. The size of the power module and cooling unit makes it difficult to input heat. Furthermore, the cooling unit has cavities for guiding the cooling medium, which adversely affect heat distribution. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a method for connecting a heating element to a cooling device, the method being low in cost and reducing the production cycle.

[0011] To address the technical problem of this invention, a method for connecting a heating element to a cooling device is proposed, wherein a connecting material, preferably a welding material or sintering paste, is arranged between the heating element and the cooling device, and further specifying that the cooling device has a cooling structure for guiding a heat transfer medium through which heat is supplied, wherein the heat transfer medium is injected with heated fluid (…). Or, in other words, the cooling structure of the cooling device is used to input heat into the connecting material.

[0012] According to the present invention, the cooling structure through which the cooling device guides the coolant or refrigerant to cool the heat-generating component is used to input heat into the connecting material by guiding a heated fluid through the cooling structure. The heated fluid heats the cooling structure or cooling device, which then dissipates the heat onto the connecting material disposed between the heat-generating component and the cooling device.

[0013] Another solution to the technical problem upon which this invention is based is a method for connecting a heating element to a cooling device, wherein a connecting material, preferably a welding material or a sintering paste, is arranged between the heating element and the cooling device, and wherein heat is input to the connecting material is achieved by the operation of the heating element.

[0014] The heat generated by the operation of the heating element is thus used to input heat into the connecting material. The heat generated by the operation of the heating element can be used to preheat the connecting parts, preferably the welding parts, and / or preheat the heating element and / or the cooling device to establish a connection, preferably a welded connection or a sintered connection. Furthermore, it is feasible to use the heat generated by the operation of the heating element to melt the connecting material, especially the welding material, in order to establish a connection, especially a welded connection, between the heating element and the cooling device.

[0015] The connecting material is arranged between the heating component and the cooling device, wherein both the heating component and the cooling device are in direct physical contact with the connecting material.

[0016] The method is preferably a welding method, more preferably a soft soldering method, or a sintering method.

[0017] Because, according to the present invention, heat input to the bonding material is achieved through the operation of the heating element and / or through the cooling structure of the cooling device infused with heated fluid, the larger-sized devices required in known reflow soldering methods can be eliminated. Heat input is improved, and process time or production cycle time can be shortened.

[0018] Preferably, heat input to the connecting material is achieved through the operation of the heating element, and the cooling device has a cooling structure for guiding the heat transfer medium through, wherein heat input to the connecting material is achieved by injecting heated fluid into the cooling structure of the cooling device.

[0019] In other words, the heat used for preheating components and connecting materials and / or for melting connecting materials and for establishing connections is provided both through waste heat generated during the operation of the heating components and through heat dissipated from the heated fluid in the cooling structure of the infusion cooling device.

[0020] It is particularly preferred that the waste heat generated during the operation of the heating element is primarily used to heat the surface of the heating element to at least the connection temperature, and that the heat dissipated from the heated fluid in the cooling structure of the infusion cooling device is greater than the waste heat of the heating element and substantially provides the heat input required to establish the connection. When the connection material is designed as a welding material, the heat dissipated from the heated fluid is sufficient to melt the welding material.

[0021] Preferably, the heating element is a power module.

[0022] Power modules, also known as power modules, are particularly used in electric transportation. Since power modules and cooling devices for them are relatively large, the method according to the invention is particularly suitable for connecting power modules to cooling devices.

[0023] Further advantageously, the heated fluid is a heated gas, preferably heated nitrogen.

[0024] In addition, it can be specified that the cooling device is a radiator or a cooling module.

[0025] Cooling devices, especially radiators or cooling modules, are preferably designed for cooling power modules of electric drives used in motor vehicles, especially battery electric vehicles.

[0026] Furthermore, it may be preferred that the connecting material be solder paste or sintering paste, especially silver sintering paste.

[0027] Solder paste can be applied to heat-generating components and / or cooling devices using known methods.

[0028] If the connecting material is sintering paste, it can be specified that the heating element and the cooling device are pressed together to apply pressure or surface pressure to the sintering paste, wherein the pressure is preferably between 5 bar and 200 bar, and more preferably between 30 bar and 50 bar.

[0029] Furthermore, it may be specified that the heating element and / or the cooling device have at least one temperature sensor, wherein the heat input, particularly spatial or temporal temperature changes, is monitored and / or controlled by using the signal from the at least one temperature sensor.

[0030] Power modules, especially power modules for electric drives in motor vehicles, and, where necessary, cooling devices for cooling such power modules, especially radiators or cooling modules, typically have temperature sensors. These inherent temperature sensors can be used within the scope of the method to monitor, and, if necessary, to regulate, the temperature changes in space or time of the heat input to the connecting material, especially the heat input spatially or temporally, by means of regulating devices provided for this purpose.

[0031] Furthermore, it can be advantageous to specify that the method is performed statically.

[0032] "statically" "Relatedly, this means that the heating element and cooling device, along with the connecting material arranged therebetween, do not need to be transported during the execution of the method as is done in an apparatus used for reflow soldering. This reduces the space requirements for performing the method and the associated costs. Because there is no need for a movable workpiece support as required in reflow soldering, the accurate positioning of the heating element relative to the cooling device can be maintained or followed. In particular, positional tolerances can be followed."

[0033] It is further advantageous to specify that the method is performed under vacuum conditions.

[0034] Therefore, the heating element and cooling device, along with the connecting material arranged therebetween, can be placed in a vacuum chamber. Performing the method under vacuum conditions helps to reduce defective areas, i.e., so-called voids.

[0035] Furthermore, it is preferable to combine the method with a convection welding method, a reflow welding method, or a vapor phase welding method.

[0036] The method according to the invention can be made more efficient by combining it with other known welding methods.

[0037] Another solution to the technical problem upon which this invention is based is a device for connecting a heating element to a cooling device, wherein the device is designed to perform the above-described method.

[0038] Another solution to the technical problem upon which this invention is based is a motor vehicle, particularly a battery-electric motor vehicle or a hybrid electric vehicle, the motor vehicle including a heat-generating component, particularly a power module, and a cooling device, particularly a cooling module, wherein the heat-generating component and the cooling module have been connected by the method described above.

[0039] All the features, functions, and design schemes described in the above method can also be adapted to devices for connecting heating components to cooling devices and to motor vehicles. Attached Figure Description

[0040] The invention will now be described in more detail with reference to the accompanying drawings. In the drawings:

[0041] Figure 1 A longitudinal section is shown, obtained by cutting through the cooling device and the heat-generating components arranged on the cooling device;

[0042] Figure 2 A top view is shown of the cooling device and the heat-generating components arranged on the cooling device; and

[0043] Figure 3 A motor vehicle with heating components and a cooling device is shown. Detailed Implementation

[0044] The following describes a method 100 for connecting the heating element 10 to the cooling device 11 with reference to the accompanying drawings. Figure 1 A schematic diagram is shown of a cooling device 11 and a heating element 10 arranged on the cooling device. A connecting material 12 is arranged between each heating element 10 and the cooling device 11. The heating element 10 is for a motor vehicle 200 (see...). Figure 3The power module 13 is a power electronic device (or power electronic device) of an electric drive. A cooling device 11 is designed as a cooling module 14 for the power module 13. The connecting material 12 is solder paste 15. In principle, the connecting material 12 could also be sintered paste, especially silver sintered paste. Because both the heating element 10 and the cooling device 11 are large, a large amount of heat is required in known methods to transfer sufficient heat into the connecting material 12 to establish a connection.

[0045] The cooling device 11 has a cooling structure 16 through which a heat transfer medium is guided. To connect the heating element 10 to the cooling device 11, a heated fluid, such as heated nitrogen, is first introduced into the internal space 18 of the cooling device 11 through inlet 17. The heated fluid further flows from the interior 18 of the cooling device 11 into the cooling structure 16 and fills the cooling structure. As the heated fluid fills the cooling structure 16, it dissipates heat to the cooling structure 16, which in turn transfers heat to the connecting material 12. Through this heat input, the connecting material 12 or solder paste 15 is melted, and a connection is established between the heating element 10 and the cooling device 11. After filling the cooling device 11, the heated fluid exits the cooling device through outlet 19.

[0046] As an alternative or supplement, the heating element 10 may also be operated. The heating element 10 generates waste heat during operation, which is also transferred to the connecting material 12 disposed between the heating element 10 and the cooling device 11. Here, the heat dissipated by the heating element 10 can also be used to melt the connecting material 12 and to establish a connection between the heating element 10 and the cooling device 11. However, the waste heat of the heating element 10 may also be used to preheat the joints on the heating element 10 and / or the cooling device 11 in a process-appropriate manner.

[0047] Figure 2 It shows Figure 1 A top view of the cooling device 11 and the heating element 10 arranged on the cooling device. The heating element 10, especially the power module 13, has a temperature sensor 20. The temperature sensor 20 can monitor and adjust the heat input to the connecting material 12, especially the spatial or temporal temperature changes of the heat input.

[0048] Figure 3 A motor vehicle 200 is schematically shown, which is designed as a battery-electric motor vehicle 21, and the motor vehicle 200 includes a heat-generating component 10, in particular a power module 13, and a cooling device 11, in particular a cooling module 14, including a cooling structure 16, wherein the power module 13 and the cooling module 14 are interconnected by the method 100 described above.

[0049] List of reference numerals

[0050] 100 methods

[0051] 200 motor vehicles

[0052] 10 Heating Components

[0053] 11 Cooling device

[0054] 12 Connecting materials

[0055] 13 Power Modules

[0056] 14 Cooling Module

[0057] 15 Solder paste

[0058] 16 Cooling Structure

[0059] 17 Entrances

[0060] 18. Interior Space

[0061] 19 Exports

[0062] 20 Temperature Sensors

[0063] 21 Battery-powered motor vehicles

Claims

1. A method (100) for connecting a power module (13) for an electric motor drive to a cooling device (11), wherein, A connecting material (12) is arranged between the power module (13) and the cooling device (11). The cooling device (11) has a cooling structure (16) for guiding the heat transfer medium through, wherein heat input to the connecting material (12) is achieved both by injecting heated fluid into the cooling structure (16) of the cooling device (11) and by the operation of the power module (13). The power module (13) and / or the cooling device (11) have at least one temperature sensor (20), wherein heat input is monitored and / or controlled by using the signal from the at least one temperature sensor (20). The waste heat generated during the operation of the power module is used to heat the surface of the power module to at least the connection temperature, and the heat dissipated from the heated fluid of the cooling structure of the infusion cooling device is greater than the waste heat of the power module and provides the heat input required to establish the connection.

2. The method (100) according to claim 1, wherein, The connecting material is a welding material or a sintering paste.

3. The method (100) according to claim 1, characterized in that, The cooling device (11) is a radiator or a cooling module (14).

4. The method (100) according to claim 1, characterized in that, The heated fluid is a heated gas.

5. The method (100) according to claim 1, characterized in that, The connecting material (12) is solder paste (15) or sintering paste.

6. The method (100) according to claim 1, characterized in that, The method may be performed statically, and / or under vacuum conditions.

7. A device for connecting a power module (13) to a cooling device (11), wherein, The device is designed to perform the method (100) according to any one of claims 1 to 6.

8. A motor vehicle (200) comprising a power module (13) and a cooling device (11), wherein, The power module (13) and the cooling device (11) are connected by the method (100) according to any one of claims 1 to 6.

9. The motor vehicle (200) according to claim 8, wherein, The motor vehicle is a battery-powered motor vehicle (21) or a hybrid electric vehicle.

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