Heat dissipation structure of power module and power module

Abstract

The invention discloses a heat dissipation structure of a power module and the power module. The heat dissipation structure comprises a heat conduction substrate which is provided with a first surface and a second surface used for installing a power device, and the first surface is provided with a metal heat dissipation layer; the heat dissipation cover is installed on the first surface of the heat conduction substrate, an evaporation cavity for containing a cooling working medium is defined between the heat dissipation cover and the heat conduction substrate, and the evaporation cavity is provided with capillary structures arranged on the inner wall of the heat dissipation cover and the metal heat dissipation layer. According to the invention, the heat conduction substrate used for installing the power device forms one part of the evaporation cavity, so that the cooling working medium can be in direct contact with the heat conduction substrate to realize rapid heat dissipation.

Description

Technical Field

[0001] The invention relates to a heat dissipation structure of a power module and a power module adopting the heat dissipation structure. Background Art

[0002] Power modules including power devices such as IGBT chips and / or MOSFET chips are widely used in various power electronic devices. Such power devices will generate a lot of heat when working. If the power module cannot dissipate the generated heat in time, it will seriously affect the operation of the power device and its surrounding electronic components.

[0003] In the prior art, power modules generally use heat sinks for heat dissipation. As an improvement, in some prior art, the power module is connected to a temperature-averaging plate or a heat pipe, and the temperature-averaging plate or the heat pipe is further connected to the heat sink, so as to conduct the heat in the power module to the heat sink more quickly through the temperature-averaging plate or the heat pipe. Among them, the temperature-averaging plate or the heat pipe is generally connected to the thermally conductive substrate of the power module through a thermally conductive medium (such as a thermal pad), and the thermal resistance generated at the connection interface will affect the heat transfer efficiency from the power module to the temperature-averaging plate or the heat pipe. Summary of the invention

[0004] In view of the deficiencies of the prior art, the main purpose of the present invention is to provide a heat dissipation structure of a power module to further improve the heat dissipation performance of the power module.

[0005] Another object of the present invention is to provide a power module having the above heat dissipation structure.

[0006] In order to achieve the above main purpose, the first aspect of the present invention discloses a heat dissipation structure of a power module, comprising:

[0007] A heat-conducting substrate having a first surface and a second surface for mounting a power device, wherein the first surface is provided with a metal heat dissipation layer;

[0008] The heat dissipation cover is installed on the first surface of the heat conductive substrate and encloses an evaporation chamber for accommodating cooling medium with the heat conductive substrate. The evaporation chamber has a capillary structure arranged on the inner wall of the heat dissipation cover and the metal heat dissipation layer.

[0009] Furthermore, the heat dissipation structure of the power module further includes: a water tank having a water inlet and a water outlet; and a heat dissipation cover at least partially contained in the water tank. When the power module is working, the circulating water flow in the water tank can quickly take away the heat of the heat dissipation cover to achieve better heat dissipation performance.

[0010] According to a specific embodiment of the present invention, the thermally conductive substrate includes an insulating substrate and a metal block or a ceramic block disposed in the insulating substrate; wherein the metal block is directly connected to the metal heat dissipation layer, and the ceramic block is directly connected to the metal heat dissipation layer or through a metal foil.

[0011] According to another specific embodiment of the present invention, the thermally conductive substrate includes a ceramic core board, and the metal heat dissipation layer is disposed on the surface of the ceramic core board.

[0012] Furthermore, a supporting structure for supporting the capillary structure is provided in the evaporation chamber to avoid or reduce the occurrence of collapse or falling of the capillary structure.

[0013] Furthermore, the bottom wall of the heat dissipation cover has hollow or non-hollow heat dissipation columns to increase the heat dissipation area of ​​the heat dissipation cover.

[0014] In order to achieve the above another object, a second aspect of the present invention provides a power module, which includes a power device and any one of the heat dissipation structures described above, wherein the power device is mounted on the second surface of the heat conductive substrate.

[0015] Furthermore, the power module also includes a packaging body, which is arranged on the second surface of the heat-conducting substrate and packages the power device therein.

[0016] Furthermore, a surface circuit electrically connected to the power device may be provided on the surface of the package body facing away from the heat-conducting substrate. The power pins and signal pins of the power module may be arranged in the surface circuit to simplify its external electrical connection structure.

[0017] Furthermore, the package body comprises a multi-layer insulating core board, and the interior of the package body has an inner conductive circuit arranged on the surface of the insulating core board.

[0018] In the present invention, the heat-conducting substrate on which the power device is mounted forms a part of the evaporation chamber, so that the cooling medium in the evaporation chamber can directly contact the heat-conducting substrate to eliminate the thermal resistance between the heat-conducting substrate and the evaporation chamber, thereby further improving the heat dissipation performance of the power module.

[0019] In order to more clearly illustrate the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0021] Figure 2 is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0022] Figure 3 is a schematic diagram of the structure of Embodiment 3 of the present invention;

[0023] Figure 4 is a schematic diagram of the structure of Embodiment 4 of the present invention;

[0024] Figure 5 is a schematic structural diagram of Embodiment 5 of the present invention;

[0025] Figure 6 It is a structural diagram of embodiment 6 of the present invention. DETAILED DESCRIPTION

[0026] In the following description, many specific details are explained in combination with the embodiments to facilitate a full understanding of the present invention. However, it should be understood that the following embodiments and detailed descriptions are only for illustrative purposes and do not limit the scope of protection of the present invention.

[0027] like Figure 1-6 As shown, the power module of the embodiment includes a heat-conducting substrate 10, one or more power devices 20 (such as IGBT chips) and a heat dissipation cover 30. The heat-conducting substrate 10 has a first surface and a second surface that are arranged opposite to each other, the heat dissipation cover 30 is connected to the first surface of the heat-conducting substrate 10, and the power device 20 is arranged on the second surface of the heat-conducting substrate 10.

[0028] The connection between the heat dissipation cover 30 and the heat conductive substrate 10 can be welded or fixed by fasteners (such as screws or bolts), and the present invention does not limit this. The heat dissipation cover 30 and the heat conductive substrate 10 enclose an evaporation chamber 40 for accommodating a cooling medium, and a negative pressure environment is formed in the evaporation chamber 40; the cooling medium can be any one or more of water, ethanol, acetone, etc., and the present invention does not limit this.

[0029] The inner wall of the evaporation chamber 40 is provided with a capillary structure so that heat can be quickly transferred from the heat-conducting substrate 10 to the heat dissipation cover 30. The capillary structure can be a porous metal layer formed by sintering metal powder (such as copper powder), a capillary mesh woven by fiber wire or metal wire (such as copper wire), and / or a capillary groove processed on the inner wall of the evaporation chamber 40. The capillary structure can also be made by other known methods, which are not limited by the present invention.

[0030] The first surface of the thermally conductive substrate 10 is provided with a first metal layer 11 as a metal heat dissipation layer. The first metal layer 11 may include a copper foil layer with a thickness of 0.2 mm to 1.0 mm, and the surface of the copper foil layer may have a corrosion-resistant coating. In a specific embodiment, the capillary structure includes a metal wire woven capillary mesh 41a arranged on the first metal layer 11 and a porous metal layer 41b arranged on the inner wall of the heat dissipation cover 30, and the edge of the metal wire woven capillary mesh 41a is in contact with the porous metal layer 41b to form a continuous capillary structure. The metal wire woven capillary mesh 41a may be arranged on the first metal layer 11 by welding.

[0031] Preferably, a support structure for supporting the capillary structure is provided in the evaporation chamber 40 to avoid or reduce the occurrence of collapse or shedding of the capillary structure. In the illustrated embodiment, the support structure includes a plurality of support columns 42 disposed between the bottom wall 31 of the heat dissipation cover 30 and the heat conductive substrate 10. The support structure may also be other structures capable of supporting the capillary structure, such as a three-dimensional skeleton, a corrugated plate, etc., which are not limited in the present invention.

[0032] In the present invention, the bottom wall 31 of the heat dissipation cover 30 may be formed in a flat plate shape, or may have a hollow or non-hollow heat dissipation column, and the arrangement of the heat dissipation column may increase the heat dissipation area of ​​the heat dissipation cover 30. Figure 1 , Figure 5 and Figure 6 As shown, the bottom wall 31 of the heat dissipation cover 30 is formed in a flat plate shape; in some embodiments, as shown in FIG. Figure 2 As shown, the bottom wall 31 of the heat dissipation cover 30 has a plurality of non-hollow (solid structure) heat dissipation columns 32; in some embodiments, as shown in FIG. Figure 3 and Figure 4 As shown, the bottom wall 31 of the heat dissipation cover 30 has a plurality of hollow heat dissipation columns 32 , and the inner walls of the plurality of hollow heat dissipation columns 32 also have a capillary structure.

[0033] Preferably, Figure 1-Figure 6 As shown, in the embodiment, at least a portion of the heat dissipation cover 30 is contained in the water tank 50, and the water tank 50 is provided with a water inlet 51 and a water outlet 52. When the power module is working, the circulating water flow in the water tank 50 can quickly take away the heat of the heat dissipation cover 30. The water tank 50 can be fixedly connected to the heat dissipation cover 30 or the heat conductive substrate 10. Optionally, the water tank 50 is fixedly connected to the heat conductive substrate 10 so that the heat dissipation cover 30 is completely contained in the water tank 50 to provide better heat dissipation performance. The connection between the water tank 50 and the heat conductive substrate 10 can be welded or fixedly connected by fasteners (such as screws or bolts), and the present invention is not limited to this.

[0034] In the embodiment, the second surface of the thermally conductive substrate 10 is provided with a second metal layer 12 connected to the power device 20, and the second metal layer 12 may include a copper foil layer with a thickness of 0.2 mm to 1.0 mm. The second metal layer 12 may have a conductive pattern 121, that is, it plays a role in transmitting current, or it may only be used for heat conduction without transmitting current, which may be specifically set according to the structure of the power device 20. The thermally conductive substrate 10 has an insulating medium arranged between the first metal layer 11 and the second metal layer 12, and the insulating medium may be a ceramic core board or an insulating substrate embedded with a thermally conductive element (such as a metal block or a ceramic block), and the present invention is not limited to this.

[0035] In some embodiments, Figure 1-3 and Figure 5-6As shown, the thermally conductive substrate 10 is a ceramic substrate, which includes a ceramic core plate 13a, and a first metal layer 11 and a second metal layer 12 are respectively arranged on two opposite surfaces of the ceramic core plate 13a. Figure 4 As shown, the insulating medium between the first metal layer 11 and the second metal layer 12 is an insulating substrate 13b embedded with a ceramic block 131, and the two sides of the ceramic block 131 are respectively welded to the first metal layer 11 and the second metal layer 12 through metal foil 132 (such as copper foil). The insulating substrate 13b can be a FR-4 substrate with a laminated structure or a resin substrate with an integrally molded structure, and the present invention is not limited to this.

[0036] As a variation of the aforementioned embodiment, the ceramic block 131 may also be directly connected to the first metal layer 11 and the second metal layer 12 (for example, connected by active metal brazing). As another variation of the aforementioned embodiment, a metal block (for example, a copper block) may be provided in the insulating substrate 13b as a heat-conducting element, and the metal block may be directly connected to the first metal layer 11 and the second metal layer 12, or may form an integral structure with the first metal layer 11 or the second metal layer 12. Among them, the heat-conducting element such as a metal block or a ceramic block may form a heat-conducting channel with good heat-conducting performance in the insulating substrate 13b, so as to quickly conduct the heat generated by the power device 20 to the first metal layer 11.

[0037] Furthermore, a packaging body 60 is provided on the second surface of the thermally conductive substrate 10. The packaging body 60 may be a resin packaging body with an integrally formed structure or a packaging body with a laminated structure, which is not limited in the present invention. Figure 1-4 As shown in FIG. 6 , the package body 60 is a resin package body having an integrally formed structure. Figure 5 As shown, the package body 60 has a laminated structure, which includes a multi-layer insulating core board 601 (e.g., a FR-4 core board) and a multi-layer bonding sheet 602 (e.g., a cured sheet); further, the package body 60 may have an inner conductive circuit (not shown in the figure) arranged on the surface of the insulating core board 601.

[0038] The power device 20 is disposed inside the package body 60. The surface of the package body 60 facing away from the heat-conducting substrate 10 is provided with a surface circuit 61 electrically connected to the power device 20. The power pins and signal pins of the power module can be disposed in the surface circuit 61 to facilitate external electrical connection. The electrical connection structure between the power device 20 and the surface circuit 61 can be designed according to the specific structure of the power device 20, and the present invention is not limited to this.

[0039] In some embodiments, Figure 1 and Figure 2As shown, the first surface of the power device 20 is provided with an S pole 211 and a G pole 212, and the second surface of the power device 20 is provided with a D pole 213. The S pole 211 and the G pole 212 are respectively electrically connected to the first pin 611 and the second pin 612 of the surface circuit 61 through corresponding metallized interconnection holes 631; the D pole 213 is connected to the conductive pattern 121 in the second metal layer 12, and is further electrically connected to the third pin 613 of the surface circuit 61 through a conductive block 62 (such as a copper block) in the package body 60; wherein the first pin 611 and the third pin 613 are power pins connected to a larger current, and the second pin 612 is a signal pin connected to a smaller current. The metallized interconnection holes 631 between the S pole 211 and the first pin 611 are preferably multiple, so as to facilitate the transmission of a larger current and heat dissipation. As a variation, the conductive pattern 121 can also be electrically connected to the third pin 613 of the surface circuit 61 through a corresponding metallized interconnection hole.

[0040] In some embodiments, Figure 6 As shown, the S pole 211 and the G pole 212 of the power device 20 are electrically connected to the conductive pattern 121 of the second metal layer 12; the S pole 211 is further electrically connected to the first pin 611 of the surface circuit 61 through a conductive block 62 (e.g., a copper block) in the package body 60, the G pole 212 is further electrically connected to the second pin 612 of the surface circuit 61 through a metallized interconnect hole 632 in the package body 60, and the D pole 213 is electrically connected to the third pin 613 of the surface circuit 61 through a plurality of metallized interconnect holes 631.

[0041] In some embodiments, Figure 3 and 4 As shown, the multiple electrodes of the power device 20 are concentrated on the first surface thereof, and the second surface opposite to the first surface is a heat dissipation surface used only for heat dissipation. At this time, the multiple electrodes on the first surface of the power device 20 can be electrically connected to the surface line 61 through the corresponding metallized interconnection holes 631 or conductive blocks, and the second surface of the power device 20 is only thermally connected to the second metal layer 12, and the second metal layer 12 can have a non-patterned structure accordingly.

[0042] It should be noted that, unless there are any contradictions or exclusions, the different embodiments disclosed above may be quoted, referenced or combined with each other, and the technical features / components of different embodiments may also be combined and / or replaced with each other.

[0043] Although the present invention has been described above through embodiments, the above embodiments are only used to exemplarily describe the feasible implementation schemes of the present invention, and are not used to limit the protection scope of the present invention. Any equivalent substitutions or changes made by those skilled in the art in accordance with the present invention should also be covered by the protection scope defined by the claims of the present invention.

Claims

1. A heat dissipation structure of a power module, characterized in that include: A heat-conducting substrate having a first surface and a second surface for mounting a power device, wherein the first surface is provided with a metal heat dissipation layer; The heat dissipation cover is installed on the first surface of the heat conductive substrate and encloses an evaporation chamber for accommodating cooling medium with the heat conductive substrate. The evaporation chamber has a capillary structure arranged on the inner wall of the heat dissipation cover and the metal heat dissipation layer.

2. The heat dissipation structure of the power module according to claim 1, characterized in that Also includes: The water tank is provided with a water inlet and a water outlet; the heat dissipation cover is at least partially accommodated in the interior of the water tank.

3. The heat dissipation structure of the power module according to claim 1, characterized in that: The thermally conductive substrate includes an insulating substrate and a metal block or a ceramic block arranged in the insulating substrate; the metal block is directly connected to the metal heat dissipation layer, and the ceramic block is directly connected to the metal heat dissipation layer or through a metal foil.

4. The heat dissipation structure of the power module according to claim 1, characterized in that: The thermally conductive substrate comprises a ceramic core plate, and the metal heat dissipation layer is arranged on the surface of the ceramic core plate.

5. The heat dissipation structure of the power module according to claim 1, characterized in that: A supporting structure for supporting the capillary structure is arranged in the evaporation chamber.

6. The heat dissipation structure of the power module according to claim 1, characterized in that: The bottom wall of the heat dissipation cover has a hollow or non-hollow heat dissipation column.

7. A power module, characterized in that: The power module comprises a power device and the heat dissipation structure according to any one of claims 1 to 6, and the power device is mounted on the second surface of the heat-conducting substrate.

8. The power module according to claim 7, characterized in that Also includes: The packaging body is arranged on the second surface of the heat-conducting substrate and packages the power device inside the packaging body.

9. The power module according to claim 8, characterized in that: A surface circuit electrically connected to the power device is provided on the surface of the package body facing away from the heat-conducting substrate.

10. The power module according to claim 8, characterized in that: The package body comprises a multi-layer insulating core board, and the interior of the package body has an inner conductive circuit arranged on the surface of the insulating core board.

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