Method for joining a cooler module to a metal plate and component

Abstract

The present invention relates to a method for joining a cooler module (4) to a metal plate by a sintering method, the cooler module (4) including a metal housing (5) having a coolant inlet (7), a coolant outlet (8), and a first housing side (9), and a coolant flow structure (6) within the housing (5), the method including the steps of introducing at least one glycol between the coolant flow structure (6), applying a sintering paste, and sintering and joining the metal plate and the first housing side (9) under pressure and heat.

Description

[Technical Field]

[0001] The present invention relates to a method for joining a cooler module to a metal plate and to a component comprising a cooler module and an electronic power module. [Background technology]

[0002] Power semiconductors in power electronics devices carry high currents. This leads to high temperatures during operation, which causes conduction losses and consequently a loss of thermal performance. To prevent this, power electronics modules are bonded to high-performance coolers. These coolers are made of aluminum, AlSiC alloys, or copper alloys. Here, the power modules can be directly attached to the surface plate of the high-performance cooler, for example, by soldering or sintering. Sintered bonding has the advantage of higher thermal conductivity than solder bonding, which allows for more effective use of the cooler's cooling capacity and better heat dissipation. However, forming a sintered bond requires high temperatures and high pressures, which can damage the often delicate flow structures inside the high-performance cooler. To prevent this, the flow structures can be supported by suitable components against the applied pressure. However, this is only effective for coolers with exposed flow structures, i.e., coolers that are not completely enclosed. This process is therefore very complicated, since on the one hand the abutment support must be adapted to the respective flow structure and on the other hand the cooler must be closed before operation. Summary of the Invention

[0003] The method according to claim 1 of the present invention is significantly simplified compared to methods known from the prior art, allowing both the formation of a stable sintered bond and the use of a closed cooler. It is not necessary to provide a specially designed support structure for supporting the flow structure of the cooler, and therefore time and costs can be saved by using the method according to the present invention.

[0004] A method according to the present invention provides for joining a cooler module to a metal plate by a sintering method. The cooler module includes a metal housing having a coolant inlet and a coolant outlet. The housing further includes a first housing side surface that is joined to the metal plate according to the present invention. A coolant flow structure is located inside the housing. The coolant flow structure is not limited in detail and is generally used to generate turbulence in the coolant flowing through the coolant flow structure, thereby enabling the coolant to absorb particularly large amounts of heat. The coolant flow structure also increases the surface area of ​​the coolant, which also contributes to particularly effective heat absorption by the coolant. For example, the coolant flow structure may be a grid structure.

[0005] The size, shape and type of the cooler are adapted to the structure to be cooled, which is represented here by a metal plate, which may for example contain electronic power modules on its surface, such as those used in power electronics devices (for example so-called power modules).

[0006] The method includes the following method steps: First, at least one glycol is introduced into the coolant flow structure. This is achieved, in particular, by filling the glycol through the coolant inlet. The coolant outlet is closed, so that the glycol remains inside the housing. After filling the coolant through the coolant inlet, the coolant inlet is also closed. In this way, the cooler becomes a closed system. In other words, conventional coolers provided for cooling power electronic devices can already be used to form sintered joints, and no open cooler is required. The cooler is used in its original state for the method. That is, the cooler is closed except for the coolant inlet and coolant outlet, which are closed after the introduction of glycol during the method according to the invention.

[0007] Furthermore, the method includes the step of applying a sintering paste.The above two method steps can be performed in this order or in the reverse order. A commercially available sintering paste is used to bond the metal plate to the corresponding metal of the first housing side surface. The sintering paste can be applied to the first housing side surface and / or the surface of the metal plate intended for bonding to the first housing side surface. This typically corresponds to the side facing the power electronics device and the bottom surface of the power electronics device.

[0008] In a further process step, sintering is performed to bond the metal plate and the first housing side. This is done using pressure and possibly heat, depending on the sintering paste used. A suitable pressure range is, for example, 10-20 MPa, and a suitable temperature range is 180-230°C.

[0009] For the implementation of the method, it is important that the glycol is essentially free of water, apart from technically unavoidable residues, since otherwise bubbles may form, for example, at the temperatures used, which would not allow for uniform abutment support and therefore would not result in a homogeneous sintered bond.

[0010] By implementing the method according to the invention, conventional coolers, which usually have very thin metal housings because they can provide high thermal conductivity, can be directly joined to a metal plate by sinter bonding. The glycol introduced into the coolant flow structure provides very good abutment support without requiring high technical or cost expenditures.

[0011] The dependent claims show preferred developments of the invention. According to an advantageous development, the glycol is selected from ethylene glycol, propylene glycol, butylene glycol and mixtures thereof, which have proven to be particularly stable at the sintering temperatures and pressures that can be used and can also be packed very well and washed out again.

[0012] As mentioned above, the structure, dimensions, and shape of the cooler module are virtually unlimited. Advantageously, the housing of the cooler module includes two half shells joined by solder joints. The half shells can be configured as lower and upper shells of the cooler module, for example, as deep-drawn parts, and include a coolant flow structure therebetween. The configuration of the cooler module with two half shells is cost-effective and can avoid additional weight due to additional components. Here, one of the half shells includes a first housing side that is joined to a metal plate by sinter bonding.

[0013] More preferably, in view of their high thermal conductivity, the cooler modules are made of aluminum, copper or stainless steel, in particular aluminum. To improve electrical conductivity and adhesion to the metal plate, aluminum or stainless steel can have a copper or silver coating, and copper can have a silver coating.

[0014] To achieve particularly efficient cooling, the cooler module advantageously includes a turbocharger. The metal plate is a copper plate because it bonds very well with the power electronics equipment and has very high thermal conductivity.

[0015] Accordingly, more advantageously, the metal plate is part of an electronic power module. According to the present invention, a component is also described that includes an electronic power module and a cooler module joined together by sinter bonding.

[0016] The cooler module includes a closed metal housing having a coolant inlet and a coolant outlet. The housing includes a coolant flow structure. The housing is formed from one or more housing components, and two or more housing components are joined to each other by solder joints. The coolant flow structure can also be joined to the housing by one or more solder joints. In other words, the cooler module according to the present invention can also be described as a solder cooler.

[0017] The electronic power module is directly bonded to the cooler module via a sinter bond with the first housing side of the cooler module. According to the present invention, the electronic power module refers to at least one semiconductor structure (particularly made of Si / SiC) including a metal plate, particularly a copper plate, on its bottom surface, which is bonded to the first housing side. Here, the copper plate can be silver-plated and can be arbitrarily thin. The metal or copper plate is used to form the sinter bond. If the sinter paste were to be directly bonded to the semiconductor structure of the electronic power module, the semiconductor structure would be damaged, impairing the performance of the electronic power module.

[0018] The component according to the invention is very lightweight and easy to construct due to the use of a solder cooler. In particular, the first housing side that is joined to the electronic power module is relatively thin, thus providing very good heat transfer to the coolant contained in the cooler module. Furthermore, the sintered joint supports high heat transfer.

[0019] Furthermore, it is advantageous that the housing and / or the coolant flow structure of the cooler module consist of aluminum, copper or stainless steel, in view of their very good thermal conductivity for dissipating heat from the electronic power module to the coolant in the cooler module. It is particularly advantageous to use aluminum or a metal (e.g. steel) coated with aluminum or copper as the material.

[0020] For particularly efficient cooling of the electronic power module, the cooler module includes a turbocharger. Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0021] [Figure 1] 1 shows a schematic cross-sectional view of a component according to an advantageous development; DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described on the basis of exemplary embodiments, in which only the essential components of the present invention are shown, and all other components are omitted for clarity. 1 shows a schematic cross-sectional view of a component 1 according to an advantageous development. The component 1 comprises an electronic power module 2 which includes at least one power semiconductor. A bottom surface 3 of the electronic power module 2 is formed from a copper metal plate.

[0023] The component 1 further includes a cooler module 4 comprising a housing 5 and a coolant flow structure 6 located within the housing 5. The cooler module 4 has a closed metal housing 5 having a coolant inlet 7 and a coolant outlet 8. Here, the housing 5 comprises, for example, two housing parts 5a and 5b, which are respectively joined to each other by solder joints. The first housing part 5a is aligned with the electronic power module 2. A first housing side surface 9 of the first housing part 5a is joined to the bottom surface 3 of the electronic power module 2 by a sintered joint 10. The bottom surface 3 of the electronic power module comprises a metal plate or is particularly configured as a metal plate, for example a copper plate.

[0024] The cooler module 4 is configured as a solder cooler. To form the sintered joint 10, the housing interior 11 can be filled with one or more glycols, which abut and support the first housing part 5a against the electronic power module 2 and also stabilize the coolant flow structure 6, preventing deformation and further damage of the components due to the pressure applied during the sintering process. The sintered joint 10 can be obtained by applying a sintering paste and sintering.

Claims

1. A method for joining a cooler module (4) to a metal plate by a sintering method, the cooler module (4) comprising a metal housing (5) having a coolant inlet (7), a coolant outlet (8) and a first housing side (9), and a coolant flow structure (6) within the housing (5); introducing at least one glycol between said coolant flow structures (6); applying a sinter paste; sintering and bonding the metal plate and the first housing side surface (9) together under pressure and heat; A method comprising:

2. 10. The method of claim 1, wherein the glycol is selected from ethylene glycol, propylene glycol, butylene glycol, and mixtures thereof.

3. 3. The method according to claim 1 or 2, wherein the housing (5) of the cooler module (4) comprises two half shells joined by a solder joint.

4. 4. The method according to any one of claims 1 to 3, wherein the cooler module (4) is made of aluminum, copper or stainless steel, in particular aluminum.

5. 5. The method according to any one of claims 1 to 4, wherein the cooler module (4) comprises a turbocharger.

6. 6. The method according to claim 1, wherein the metal plate is a copper plate.

7. 7. The method according to any one of claims 1 to 6, wherein the metal plate is part of an electronic power module (2).

8. 1. A component comprising an electronic power module (2) and a cooler module (4), said electronic power module (2) and said cooler module (4) being joined together by a sintered joint (10), said cooler module (4) comprising a closed metal housing (5) having a coolant inlet (7) and a coolant outlet (8) and a coolant flow structure (6) within said housing (5), said housing comprising housing parts (5a, 5b) joined together respectively by solder joints.

9. 9. The component according to claim 8, wherein the housing (5) and / or the coolant flow structure (6) of the cooler module (4) consists of aluminum, copper or stainless steel, in particular of aluminum and / or is coated with aluminum or copper.

10. 10. A component according to claim 8 or 9, wherein the cooler module (4) comprises a turbocharger.

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