A power module and a method for assembling a power module

Abstract

The present application provides a power module and a method for assembling a power module. The power module includes an insulated metal plate, a plastic housing, and a crystal chip. The insulated metal plate is disposed on a heat sink. The plastic housing is disposed on the insulated metal plate and forms an accommodating cavity with the insulated metal plate. The edge of the insulated metal plate extends outside the accommodating cavity. The crystal chip is disposed on the side of the insulated metal plate away from the heat sink and is located within the accommodating cavity. The edge of the insulated metal plate extending outside the accommodating cavity is fixed to the heat sink through a fixing member. The power module directly fixes the insulated metal plate to the heat sink at the edge portion extending outside the plastic housing, which can avoid the problem that the plastic housing is easily broken due to locking. During assembly, the crystal chip can be directly soldered onto the insulated metal plate, and then the plastic housing can be bonded onto the insulated metal plate using an adhesive to perform subsequent process flows, which simplifies the process flow compared to the existing assembly methods.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor power devices, and more particularly, to a power module and a method for assembling the power module. Background Art

[0002] As a series of general IGBT (Insulate-Gate Bipolar Transistor) module products, Econo Pack is applicable to industrial variable frequency drives, commercial HVAC, wind turbines, auxiliary inverters of CAV commercial vehicles and other application scenarios. The Econo Pack module adopts a half-bridge, four-bridge or six-bridge topology configuration and is suitable for the design of various inverters. The common structure of the existing Econo Pack power module is as shown in Figure 1 and Figure 2 , and mainly includes a housing, a copper base plate, a ceramic substrate, a chip, and aluminum wires. The power module is attached to the heat sink through a locking accessory, and a thermal paste is used to bond between the copper base plate and the heat sink to ensure the smooth conduction of the heat flow between the two.

[0003] In the existing power module, a thermal paste is required to bond between the power module and the heat sink, and then it is attached to the heat sink through a locking accessory. When abnormal situations such as too high locking force, too much or uneven thermal paste, and too large warping amount of the copper base plate occur, the plastic housing is prone to crack at the attachment point, as shown in Figure 3 . Moreover, when the existing power module is assembled and formed, the chip and the ceramic substrate need to be welded once with a solder (tin solder), then the ceramic substrate and the copper base plate need to be welded twice with a solder, and then the housing is adhesively assembled with an adhesive. Finally, processes such as aluminum wire bonding and sealant pouring are carried out, and the process flow is very complicated. Summary of the Invention

[0004] The objectives of the present invention include, for example, providing a power module and a method for assembling the power module, which can avoid the occurrence of cracking problems and simplify the assembly process.

[0005] Embodiments of the present invention may be implemented as follows:

[0006] In a first aspect, the present invention provides a power module, including:

[0007] An insulated metal plate disposed on the heat sink;

[0008] A plastic housing disposed on a side of the insulated metal plate away from the heat sink and located at a periphery of the insulated metal plate to form an accommodation cavity with the insulated metal plate, and an edge of the insulated metal plate extends outside the accommodation cavity;

[0009] A crystal chip, which is disposed on a side of the insulating metal plate away from the heat dissipation plate and is located within the accommodation cavity;

[0010] Wherein, an edge of the insulating metal plate extending outside the accommodation cavity is fixed to the heat dissipation plate by a fixing member.

[0011] In an alternative embodiment, the insulating metal plate includes a metal substrate, an insulating heat transfer layer, and a heat conductive thin film;

[0012] The metal substrate is disposed on the heat dissipation plate;

[0013] The insulating heat transfer layer is disposed on a side of the metal substrate away from the heat dissipation plate;

[0014] The heat conductive thin film is disposed on a side of the insulating heat transfer layer away from the metal substrate;

[0015] Wherein, an edge of the metal substrate extends outside the accommodation cavity and is fixed to the heat dissipation plate by a fixing member, and the insulating heat transfer layer and the heat conductive thin film are located within the accommodation cavity.

[0016] In an alternative embodiment, a side wall of the plastic housing is formed with a notch that is recessed inwardly towards the inside of the plastic housing;

[0017] The metal substrate is directly fixed to the heat dissipation plate by a fixing member at the position of the notch.

[0018] In an alternative embodiment, a cross-sectional shape of the notch is a rounded corner shape or a right angle shape.

[0019] In an alternative embodiment, a fixing hole is formed at an edge of the metal substrate extending outside the accommodation cavity, and a matching hole is formed at a position of the heat dissipation plate corresponding to the fixing hole;

[0020] The metal substrate is fixed to the heat dissipation plate based on the fixing hole and the matching hole and by a fixing member.

[0021] In an alternative embodiment, a thickness of the metal substrate is 2 mm - 3 mm, and a material of the metal substrate is copper or aluminum.

[0022] In an alternative embodiment, a thickness of the insulating heat transfer layer is 0.10 mm - 0.18 mm, and a thermal conductivity is greater than 10 W / m·K.

[0023] In an alternative embodiment, the heat conductive thin film is made of copper foil, and a thickness of the heat conductive thin film is 0.5 mm - 1.0 mm.

[0024] In an alternative embodiment, the power module further includes a heat conductive layer;

[0025] The heat-conducting layer is disposed between the metal substrate and the heat sink plate.

[0026] In a second aspect, the present invention provides a method for assembling a power module for assembling the power module according to any one of the foregoing embodiments. The method includes:

[0027] Providing a crystal chip and an insulated metal plate;

[0028] Welding the crystal chip to the insulated metal plate using a solder;

[0029] Using an adhesive to bond a plastic housing to the periphery of the insulated metal plate on the side where the crystal chip is disposed to form a receiving cavity with the insulated metal plate;

[0030] Wherein, the edge of the insulated metal plate extends outside the receiving cavity so that the heat sink plate can be fixed by a fixing member at the edge position of the insulated metal plate extending outside the receiving cavity.

[0031] The beneficial effects of the embodiments of the present invention include, for example:

[0032] The present application provides a power module and a method for assembling a power module. The power module includes an insulated metal plate, a plastic housing, and a crystal chip. Among them, the insulated metal plate is disposed on the heat sink plate, the plastic housing is disposed on the insulated metal plate and is located at the periphery of the insulated metal plate to form a receiving cavity with the insulated metal plate. The edge of the insulated metal plate extends outside the receiving cavity, and the crystal chip is disposed on the side of the insulated metal plate away from the heat sink plate and is located within the receiving cavity. Among them, the edge of the insulated metal plate extending outside the receiving cavity is fixed to the heat sink plate by a fixing member. The power module directly fixes the edge portion of the insulated metal plate extending out of the plastic housing to the heat sink plate, which can avoid the problem that the plastic outer shell is easily broken due to locking.

[0033] Furthermore, in the method for assembling a power module provided by the present application, the crystal chip can be directly welded to the insulated metal plate, and then the plastic housing can be bonded to the insulated metal plate using an adhesive to perform subsequent process flows, which simplifies the process flow compared with the existing assembly method. Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0035] Figure 1 is a schematic structural view of a power module from a top-down perspective in the prior art;

[0036] Figure 2 is one of the schematic structural views of the power module from a side perspective in the prior art;

[0037] Figure 3 is another schematic structural view of the power module from a side perspective in the prior art;

[0038] Figure 4 is the schematic structural view of the power module from a side perspective in the embodiment of the present application;

[0039] Figure 5 is the schematic structural view of the power module from a top-down perspective in the embodiment of the present application;

[0040] Figure 6 is Figure 5 the local enlarged schematic view of the middle part A;

[0041] Figure 7 is the schematic structural view of the power module from a bottom-up perspective in the embodiment of the present application;

[0042] Figure 8 is the flowchart of the power module assembly method provided by the embodiment of the present application.

[0043] Icon: 00 - heat dissipation plate; 10 - insulating metal plate; 11 - metal substrate; 12 - insulating heat transfer layer; 13 - thermal conductive film; 20 - plastic housing; 21 - notch; 30 - crystal chip; 40 - fixing member; 50 - metal connecting member; 60 - signal terminal; 70 - thermal conductive layer. Detailed Embodiments

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. The components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0046] It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, it is not necessary to further define and explain it in subsequent figures. At the same time, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0047] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the said element.

[0048] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this application is usually placed during use. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present application.

[0049] In the description of the present application, it should also be noted that unless otherwise clearly defined and limited, the terms "arranged", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0050] The following will describe in detail some embodiments of the present application with reference to the drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0051] Please refer to Figure 4, an embodiment of the present application provides a power module, which includes an insulating metal plate 10, a plastic housing 20, and a crystal chip 30. Among them, the insulating metal plate 10 is disposed on a heat sink 00. The plastic housing 20 is disposed on a side of the insulating metal plate 10 away from the heat sink 00 and located at the periphery of the insulating metal plate 10. The plastic housing 20 and the insulating metal plate 10 enclose to form an accommodation cavity, and an edge of the insulating metal plate 10 extends out of the accommodation cavity. The crystal chip 30 is disposed on a side of the insulating metal plate 10 away from the heat sink 00 and located within the accommodation cavity.

[0052] In this embodiment, an edge of the insulating metal plate 10 extending out of the accommodation cavity is fixed to the heat sink 00 through a fixing member 40.

[0053] In this embodiment, the power module is disposed on the heat sink 00. The heat sink 00 can be a heat sink fin. When the power module is working, heat will be generated. If the heat cannot be dissipated in time and effectively, the performance of the power module will be affected. The heat sink 00 can be used to dissipate the heat generated by the power module to avoid excessive heat inside the power module.

[0054] In the vertical direction, the insulating metal plate 10 includes a first surface and a second surface opposite to the first surface. Among them, the insulating metal plate 10 is attached to the heat sink 00 through the first surface, and the crystal chip 30 and the plastic housing 20 are both disposed on the second surface of the insulating metal plate 10.

[0055] The number of crystal chips 30 can be one, two, or more. Generally, there are multiple crystal chips 30 included in the power module. Metal connectors 50 are connected to each crystal chip 30, and the current on the crystal chip 30 can be led out through the metal connectors 50. Among them, the metal connectors 50 can be metal wires or metal sheets.

[0056] The plastic housing 20 includes a housing side wall located around and a housing top wall connected to the housing side wall. The bottom of the plastic housing 20 is an opening. The plastic housing 20 covers the periphery of the insulating metal plate 10 and encloses with the insulating metal plate 10 through the housing side wall and the housing top wall to form an accommodation cavity. A part of the insulating metal plate 10 is located within the accommodation cavity and another part extends out of the accommodation cavity.

[0057] The housing top wall of the plastic outer shell is provided with a plurality of holes. Figure 4The structural schematic diagram shown only shows some components included in the power module. In addition, the power module may further include other components. For example, it may further include signal terminals 60, and the number of signal terminals 60 may be multiple. The number of signal terminals 60 is consistent with the number of holes in the top wall of the plastic housing. One end of each signal terminal 60 is disposed on the part of the insulating metal plate 10 located within the accommodation cavity, and the other end extends out of the accommodation cavity through the corresponding hole.

[0058] In this embodiment, the insulating metal plate 10 is a plate-like structure. A part of the insulating metal plate 10 is located within the accommodation cavity, and the edge part is located outside the accommodation cavity. For example, when the insulating metal plate 10 is a rectangular plate-like structure, the peripheral angle part of the insulating metal plate 10 extends out of the accommodation cavity, or the edges around the insulating metal plate 10 extend out of the accommodation cavity, or a part of the edges around the insulating metal plate 10 extends out of the accommodation cavity.

[0059] The part of the insulating metal plate 10 that extends out of the accommodation cavity is locked and fixed to the lower heat sink 00 through the fixing member 40.

[0060] For the power module provided in this embodiment, the insulating metal plate 10 is used to replace the ceramic substrate and the copper bottom plate in the existing design. The edge of the insulating metal plate 10 extends outside the plastic housing 20 and is directly locked to the lower heat sink 00 through the fixing member 40. In this way, directly locking to the plastic housing 20 is avoided, and thus the rupture of the plastic housing 20 can be avoided.

[0061] In this embodiment, the insulating metal plate 10 includes a metal substrate 11, an insulating heat transfer layer 12, and a heat-conducting thin film 13. Among them, the metal substrate 11 is disposed on the heat sink 00, the insulating heat transfer layer 12 is disposed on the side of the metal substrate 11 away from the heat sink 00, and the heat-conducting thin film 13 is disposed on the side of the insulating heat transfer layer 12 away from the metal substrate 11.

[0062] Among them, the edge of the metal substrate 11 extends outside the accommodation cavity of the plastic housing and is locked and fixed to the heat sink 00 through the fixing member 40. The insulating heat transfer layer 12 and the heat-conducting thin film 13 are located within the accommodation cavity.

[0063] In this embodiment, a notch 21 that shrinks inward in the direction of the inside of the plastic housing 20 is formed on the side wall of the plastic housing 20. The metal substrate 11 is directly fixed to the heat sink 00 through the fixing member 40 at the position of the notch 21.

[0064] In a possible implementation, such as Figure 5 , Figure 6 , Figure 7As shown in the figure, in the top-down view, the overall shape of the plastic housing 20 is rectangular, and the metal substrate 11 is also rectangular. The peripheral corners of the plastic housing 20 are recessed inward towards the inside of the plastic housing 20 to form notches 21. Among them, the number of notches 21 can be two or four. For example, notches 21 can be formed at two diagonal peripheral corners of the four peripheral corners of the plastic housing 20, or notches 21 can be formed around each of the four peripheral corners of the plastic housing 20. In this embodiment, in order to ensure the firm connection between the power module and the heat sink 00, inwardly recessed notches 21 can be formed at each peripheral corner position.

[0065] Due to the inwardly recessed notches 21 formed on the plastic housing 20, the metal substrate 11 below will be exposed at the notch 21 position. The exposed metal substrate 11 is the part of the metal substrate 11 extending out of the accommodation cavity of the plastic housing 20. At the position of the metal substrate 11 located at the notch 21, it is directly locked and fixed to the heat sink 00 through the fixing member 40. In this way, the problem that the plastic housing 20 is easily broken due to being locked to the plastic housing 20 can be avoided.

[0066] In another possible implementation, the notches 21 formed on the plastic housing 20 can also be located on the side of the plastic housing 20. For example, notches 21 can be formed on the side wall of the housing located on the rectangular side. For example, notches 21 can be formed on the two side walls of the opposite sides, or notches 21 can be formed on the side walls of each side.

[0067] Similarly, the notches 21 formed on the side wall of the housing will expose the metal substrate 11 below, and the exposed part is a partial area on the rectangular side of the metal substrate 11. The metal substrate 11 is directly locked and fixed to the heat sink 00 below through the fixing member 40 in the exposed area. In this way, by locking the heat sink 00 at the positions of each side of the metal substrate 11, a stable locking effect can also be achieved.

[0068] In this embodiment, the cross-sectional shape of the notch 21 formed on the plastic housing 20 can be a rounded corner shape or a right angle shape. Considering that the commonly used fixing member 40 is a screw and its top shape is usually circular, in order to be as compatible with the shapes of surrounding components as possible, the notch 21 can be set as a notch 21 with a rounded corner cross-sectional shape.

[0069] In addition, since the notch 21 with a right angle shape is simpler in the manufacturing process, from the perspective of simplifying the process, the notch 21 can also be set as a notch 21 with a right angle cross-sectional shape, as long as the position reserved by the formed notch 21 can accommodate the fixing member 40.

[0070] In this embodiment, fixing holes are formed at the edges of the metal substrate 11 extending out of the accommodating space of the plastic housing 20, matching holes are formed at positions corresponding to the fixing holes on the heat dissipation plate 00, and the metal substrate 11 is fixed to the heat dissipation plate 00 based on the fixing holes and the matching holes through fixing members 40.

[0071] The fixing holes on the metal substrate 11 can be formed during the manufacturing process. The fixing holes can be located at the respective circumferential corners of the rectangular metal substrate 11, and / or at the positions of the respective sides of the metal substrate 11, such as the middle positions of the respective sides.

[0072] The fixing member 40 can be a screw. By passing the screw through the fixing hole on the metal substrate 11 and the matching hole on the heat dissipation plate 00, the metal substrate 11 can be directly locked and fixed to the heat dissipation plate 00 to tightly connect the metal substrate 11 and the heat dissipation plate 00.

[0073] In this embodiment, the material of the metal substrate 11 is copper or aluminum. The metal substrate 11 made of copper or aluminum has good toughness and rigidity. Compared with the existing design that requires attaching accessories to the plastic shell for plastic design, in this embodiment, direct locking and fixing are carried out on the metal substrate 11. Due to the toughness and rigidity of the metal substrate 11 and other characteristics, the problem of cracking can be avoided.

[0074] In this embodiment, the thickness of the metal substrate 11 is 2 mm - 3 mm. Compared with the 3 mm thick copper bottom plate commonly used in the existing design, the cost can be lower. Moreover, the metal substrate 11 with a thickness of 2 mm - 3 mm can ensure its rigidity and toughness, and avoid the problem of cracking.

[0075] In this embodiment, the thickness of the insulating heat transfer layer 12 is 0.10 mm - 0.18 mm, and the thermal conductivity is greater than 10 W / m·K. The insulating heat transfer layer 12 uses a material with high thermal conductivity, which can ensure its good heat conduction performance under a relatively thin thickness. Compared with the thermal conductivity of the 0.38 mm thick ceramic substrate in the conventional design, it is between one - half and one - third of it.

[0076] In this embodiment, the heat conduction film 13 is made of copper foil, and the thickness of the heat conduction film 13 is 0.5 mm - 1.0 mm. By setting the thickness of the heat conduction film 13 to be relatively thick, compared with the 0.2 mm to 0.4 mm copper bottom plate in the existing design, its heat dissipation ability can be significantly improved, the junction temperature of the crystal chip 30 can be decreased, the thermal resistance can be reduced, the power can be lowered, and the efficiency can be improved.

[0077] In this embodiment, the power module further includes a heat conduction layer 70 disposed between the metal substrate 11 and the heat dissipation plate 00. The heat conduction layer 70 can be a layer formed by heat conduction paste. Besides playing the role of heat conduction, the heat conduction paste can also serve as an adhesive between the metal substrate 11 and the heat dissipation plate 00 to achieve a tight fit between the metal substrate 11 and the heat dissipation plate 00.

[0078] For the power module provided in this embodiment, an insulating metal plate 10 is used to replace the ceramic substrate and the copper bottom plate in the existing design. Moreover, the insulating metal plate 10 extends directly outside the accommodating cavity formed by the plastic housing 20, and a notch 21 is formed in combination with the inward contraction design of the plastic housing 20. The extended part of the insulating metal plate 10 is directly locked and fixed to the heat dissipation plate 00 at the position of the notch 21 formed by inward contraction through a fixing member 40. Based on the good rigidity and toughness of the insulating metal plate 10, and being directly locked to the insulating metal plate 10 without locking to the plastic housing 20, the problem of cracking of the plastic housing 20 can be avoided.

[0079] In addition, the embodiment of the present application also provides a power module assembly method, which can assemble a power module in any implementation manner of the above embodiments. Please refer to Figure 8 , the power module assembly method includes the following steps:

[0080] S11, providing a crystal chip 30 and an insulating metal plate 10.

[0081] S12, welding the crystal chip 30 to the insulating metal plate 10 using a welding material.

[0082] S13, using an adhesive to bond the plastic housing 20 to the periphery of the insulating metal plate 10 on the side where the crystal chip 30 is disposed to form an accommodating cavity with the insulating metal plate 10. Among them, the edge of the insulating metal plate 10 extends outside the accommodating cavity so that the fixing member 40 can be used to fix the insulating metal plate 10 to the heat dissipation plate 00 at the edge position extending outside the accommodating cavity.

[0083] For the power module assembly method provided in this embodiment, since the module assembly is based on the insulating metal plate 10, the crystal chip 30 can be directly welded to the insulating metal plate 10, and then the plastic housing 20 can be bonded to the insulating technology plate using an adhesive to carry out subsequent process flows. Compared with the existing assembly methods, the process flows are simplified.

[0084] The power module assembly method in this embodiment is used to assemble the power module in the above embodiment. The power module involved in the assembly method in this embodiment has the same structure and beneficial effects as the above power module. The structure and beneficial effects of the power module have been described in detail in the foregoing embodiments and will not be elaborated here.

[0085] In summary, the power module provided by the embodiment of the present application includes an insulating metal plate 10, a plastic housing 20, and a crystal chip 30. Among them, the insulating metal plate 10 is disposed on the heat sink 00, the plastic housing 20 is disposed on the insulating metal plate 10 and located at the periphery of the insulating metal plate 10 to form an accommodating cavity with the insulating metal plate 10. The edge of the insulating metal plate 10 extends outside the accommodating cavity. The crystal chip 30 is disposed on the side of the insulating metal plate 10 away from the heat sink 00 and located within the accommodating cavity. Among them, the edge of the insulating metal plate 10 extending outside the accommodating cavity is fixed to the heat sink 00 through a fixing member 40. This power module directly fixes the insulating metal plate 10 to the heat sink 00 at the edge portion extending out of the plastic housing 20, which can avoid the problem that the plastic housing 20 is easily broken due to locking.

[0086] Furthermore, the power module assembly method provided by the embodiment of the present application can directly weld the crystal chip 30 on the insulating metal plate 10, and then use an adhesive to bond the plastic housing 20 to the insulating metal plate 10 to carry out the subsequent process flow, which simplifies the process flow compared with the existing assembly method.

[0087] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A power module, characterized in that, Comprising: An insulating metal plate, which is disposed on the heat dissipation plate; A plastic housing, which is disposed on the side of the insulating metal plate away from the heat dissipation plate and at the periphery of the insulating metal plate to form an accommodating cavity with the insulating metal plate. The edge of the insulating metal plate extends outside the accommodating cavity, and the plastic housing is bonded to the insulating metal plate by an adhesive; A crystal chip, which is disposed on the side of the insulating metal plate away from the heat dissipation plate and within the accommodating cavity; Wherein, the edge of the insulating metal plate extending outside the accommodating cavity is fixed to the heat dissipation plate by a fixing member; The insulating metal plate includes a metal substrate, an insulating heat transfer layer, and a heat conduction film; The metal substrate is disposed on the heat dissipation plate; The insulating heat transfer layer is disposed on the side of the metal substrate away from the heat dissipation plate; The heat conduction film is disposed on the side of the insulating heat transfer layer away from the metal substrate; Wherein, the edge of the metal substrate extends outside the accommodating cavity and is fixed to the heat dissipation plate by a fixing member, and the insulating heat transfer layer and the heat conduction film are located within the accommodating cavity; The side wall of the plastic housing is formed with a notch that shrinks inward in the direction of the interior of the plastic housing; The metal substrate is directly fixed to the heat dissipation plate by a fixing member at the notch position; 2. The power module according to claim 1, wherein The cross-sectional shape of the notch is a rounded corner shape or a right angle shape; 3. The power module according to claim 1, characterized in that, The edge of the metal substrate extending outside the accommodating cavity is provided with a fixing hole, and a matching hole is provided at the position of the heat dissipation plate corresponding to the fixing hole; The metal substrate is fixed to the heat dissipation plate based on the fixing hole and the matching hole and by a fixing member; 4. The power module according to claim 1, wherein The thickness of the metal substrate is 2 mm - 3 mm, and the material of the metal substrate is copper or aluminum; 5. The power module according to claim 1, wherein The thickness of the insulating heat transfer layer is 0.10 mm - 0.18 mm, and the thermal conductivity is greater than 10 W / m·K; 6. The power module according to claim 1, wherein The heat conduction film is made of copper foil, and the thickness of the heat conduction film is 0.5 mm - 1.0 mm; 7. The power module according to claim 1, characterized in that The power module further includes a heat conduction layer; The heat conduction layer is disposed between the metal substrate and the heat dissipation plate; 8. A method for assembling a power module, characterized in that, For assembling to form the power module according to any one of claims 1 - 7, the method includes: Providing a crystal chip and an insulating metal plate; Welding the crystal chip to the insulating metal plate using a solder; Bonding a plastic housing to the periphery of the insulating metal plate on the side where the crystal chip is disposed using an adhesive to form an accommodating cavity with the insulating metal plate; Wherein, the edge of the insulating metal plate extends outside the accommodating cavity so that a fixing member can be used to fix the edge of the insulating metal plate extending outside the accommodating cavity to the heat dissipation plate.

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