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

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 a component including the cooler module and an electronic power module.

Background Art

[0002] Power semiconductors in power electronics devices carry high currents. As a result, they reach high temperatures during operation, which causes conduction losses and consequently a loss of thermal performance. To avoid this, the power electronics module is joined to a high-performance cooler. This cooler is made of aluminum, AlSiC alloy, or copper alloy. Here, the power module can be mounted directly on the surface plate of the high-performance cooler, that is, for example, soldered or sintered. The sintered joint has the advantage of higher thermal conductivity compared to a soldered joint, whereby the cooling capacity of the high-performance cooler can be utilized more effectively for cooling the power electronics module, and the heat of the power electronics module can be dissipated better. However, in order to form a sintered joint, high pressure is used in addition to high temperature. These can damage the often delicately configured flow structures inside the high-performance cooler. To prevent this, the flow structure can be abutted and supported by suitable components against the pressure that can be applied. However, this is only effective for coolers with exposed flow structures, that is, coolers that are not closed over their entire surface. This process is therefore very cumbersome, 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 Invention

[0003] The method according to claim 1 of the present invention is a significantly simplified method compared to methods known from the prior art, enabling both the formation of a stable sintered joint and the use of a closed cooler. It is not necessary to provide a contact support structure specifically configured to contact and support the cooler's flow structure; therefore, time and cost can be saved by utilizing the method according to the present invention.

[0004] A method according to the present invention is provided for joining a cooler module to a metal plate by a sintering method, wherein the cooler module includes a metal housing having a coolant inlet and a coolant outlet. The housing further includes a first housing side which is joined to the metal plate according to the present invention. Inside the housing is a coolant flow structure. The coolant flow structure is not limited in detail, but is generally used to generate turbulence in the coolant flowing through the coolant flow structure, thereby allowing the coolant to absorb a particularly large amount 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 being cooled. Here, the structure being cooled is represented by a metal plate. The metal plate may, for example, have electronic power modules on its surface, such as those used in power electronics equipment (e.g., so-called power modules).

[0006] This method includes the following steps: First, at least one glycol is introduced into the coolant flow structure. This is achieved in particular by filling the coolant inlet with glycol. The coolant outlet is closed, and thus 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, a conventional cooler provided for cooling power electronics equipment can already be used to form a sintered bond and does not require an open cooler. The cooler is used as is for this method. That is, the cooler is closed except for the coolant inlet and coolant outlet, which are closed after the introduction of glycol in the method according to the present invention.

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

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

[0009] For this method to be implemented, it is important that the glycol is essentially water-free, except for technically unavoidable residues. Otherwise, bubbles may form at the operating temperature, for example, and these bubbles will not allow for uniform contact support, thus preventing the formation of a homogeneous sintered bond.

[0010] By implementing the method according to the present invention, conventional coolers, which typically have very thin metal housings that provide high thermal conductivity, can be directly bonded to metal plates by sintering. The glycol introduced into the coolant flow structure provides excellent contact support without requiring high technical or cost burdens.

[0011] The dependent claims represent preferred developments of the present invention. According to favorable developmental forms, glycols are selected from ethylene glycol, propylene glycol, butylene glycol, and mixtures thereof. The above glycols have been demonstrated to be particularly stable at the sintering temperatures and pressures at which they can be used, and furthermore, they can be filled very well and can be washed away again.

[0012] As previously stated, there are virtually no restrictions on the structure, dimensions, and shape of the cooler module. Advantageously, the housing of the cooler module includes two half-shells joined by soldering. The half-shells, as the lower and upper shells of the cooler module, can be constructed, for example, as deep-drawn parts, with a coolant flow structure between them. The configuration of a cooler module with two half-shells is cost-effective and eliminates the additional weight of further components. Here, one of the half-shells includes a first housing side joined to a metal plate by sintering.

[0013] Further advantageously, given their high thermal conductivity, the cooler modules are formed from aluminum, copper, or stainless steel, and are particularly made of aluminum. To improve conductivity and adhesion to metal plates, aluminum or stainless steel may have a copper coating or a silver coating, and copper may have a silver coating.

[0014] To achieve particularly efficient cooling, the cooler module advantageously includes a turbocharger. The metal plate is made of copper because it has excellent bonding properties with power electronics equipment and also possesses very high thermal conductivity.

[0015] Accordingly, and even more advantageously, the metal plate is part of the electronic power module. The present invention also describes a component including an electronic power module and a cooler module joined to each other by sintering.

[0016] The cooler module is a cooler module comprising a closed metal housing having a coolant inlet and a coolant outlet. Within the housing is a coolant flow structure. The housing is formed from one or more housing components, two or more of which 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 sintered bond with the first housing side of the cooler module. According to the present invention, the electronic power module means at least one semiconductor structure (particularly made from Si / SiC) having 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 made optionally thin. The metal plate or copper plate is used to form a sintered bond. If the sintered paste is directly bonded to the semiconductor structure of the electronic power module, the semiconductor structure will be damaged and the performance of the electronic power module will be impaired.

[0018] The component according to the present invention is extremely lightweight and easily constructed due to the use of a solder cooler. In particular, the first housing side that is joined to the electronic power module is made relatively thin, thus providing very good heat transfer to the coolant contained in the cooler module. Furthermore, high heat transfer is supported by sintering bonding.

[0019] A further advantage is that, in light of the excellent thermal conductivity required for dissipating heat from the electronic power module to the coolant within the cooler module, the housing and / or coolant flow structure of the cooler module is made of aluminum, copper, or stainless steel. Particularly advantageous is the use of 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. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the attached drawings. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic cross-sectional view of a component in a favorable developmental form. [Modes for carrying out the invention]

[0022] The present invention is described based on exemplary embodiments. Here, only the essential components of the invention are shown, and all other components are omitted for clarity. In detail, Figure 1 shows a schematic cross-sectional view of component 1 in an advantageous developmental form. Component 1 includes an electronic power module 2 containing at least one power semiconductor. The bottom surface 3 of the electronic power module 2 is formed from a copper metal plate.

[0023] 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 joined to each other by solder joints. The first housing part 5a is aligned with the electronic power module 2. The first housing side 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 includes a metal plate, or is configured as a metal plate such as, for example, a copper plate.

[0024] The cooler module 4 is configured as a solder cooler. One or more glycols can be filled into the housing interior 11 to form a sintered joint 10, thereby supporting the first housing component 5a in contact with the electronic power module 2, stabilizing the coolant flow structure 6, and 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 it.

Claims

1. A method for joining a cooler module (4) to a metal plate by sintering, wherein the cooler module (4) includes 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 metal housing (5), The steps include introducing at least one glycol between the coolant flow structures (6), The steps include applying the sintered paste and The steps include sintering and joining the metal plate and the first housing side surface (9) under pressure and heating, and A method that includes this.

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

3. The method according to claim 1, wherein the metal housing (5) of the cooler module (4) includes two half-shells joined by soldering.

4. The method according to claim 1, wherein the cooler module (4) is made of aluminum, copper, or stainless steel.

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

6. The method according to claim 1, wherein the metal plate is part of the electronic power module (2).

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