A package structure of a power device module

Abstract

The application discloses a packaging structure of a power device module, and particularly relates to the technical field of power device modules, a power device module, and a power device module which is packaged into an integrated module by a power device body, elastic terminals and a current-carrying heat conductor through a plastic sealing body. The upper portion of the plastic sealing body is provided with a supporting column, the upper portion of the supporting column is provided with a positioning pin, the surface of the positioning pin is provided with a PCB, and a gap between the supporting end face of the supporting column and the PCB is reserved as an elastic deformation compensation space. The PCB and the elastic terminals are fixed by welding, and the bottom of the current-carrying heat conductor is provided with an external heat dissipation surface. The PCB and the Z-shaped elastic terminals are directly connected through reflow soldering, the bonding wire is cancelled, the parasitic inductance is reduced, and the switching loss is reduced. The floating compensation structure is composed of the positioning pin, the supporting column and the Z-shaped elastic terminals, the gap between the supporting column and the PCB is reserved for terminal deformation, the assembly tolerance is offset by the Z-shaped elastic terminals, the module heat dissipation surface is closely attached to the heat dissipation plate, and the contact thermal resistance is reduced.

Description

Technical Field

[0001] This invention relates to the field of power device module technology, and more specifically, to a packaging structure for a power device module. Background Technology

[0002] A power module is a modular solution that integrates various power semiconductor devices (such as IGBTs, MOSFETs, diodes, etc.) and drive circuits into one unit. It is suitable for high-power electronic devices and is designed to handle power control and conversion tasks with high voltage and high current, such as motor drives, inverters, power systems, electric vehicle drives, and industrial frequency converters.

[0003] Current power module packaging structures have many defects. On the one hand, traditional modules have poor electrical integration. The PCB and power terminals are connected by bonding wires, which is cumbersome and generates large parasitic inductance, increasing the switching losses of the devices. On the other hand, power terminals are mostly rigid straight bars without elastic compensation structures or matching structures with floating positioning pins and support columns to leave gaps. They cannot compensate for the tolerances generated during assembly through the deformation of the terminals themselves, resulting in the bottom heat dissipation surface of the power module not being able to fit tightly with the heat sink, resulting in high interface contact thermal resistance and insufficient heat dissipation stability. To address these issues, we propose a packaging structure for power device modules. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a packaging structure for a power device module to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a packaging structure for a power device module, comprising: a power device module, wherein the power device module is an integral module consisting of a power device body, elastic terminals and a current-carrying heat conductor encapsulated in a plastic encapsulation body; a support column is provided on the upper part of the plastic encapsulation body; a positioning pin is provided on the upper part of the support column; a PCB board is provided on the surface of the positioning pin; a gap is reserved between the support end face of the support column and the PCB board as an elastic deformation compensation space; the PCB board is welded and fixed to the elastic terminals; an external heat dissipation surface is provided at the bottom of the current-carrying heat conductor; and a heat dissipation base plate assembly is threadedly connected to the lower part of the external heat dissipation surface. The heat dissipation base plate assembly includes a heat dissipation plate set at the bottom of the external heat dissipation surface. The bottom of the heat dissipation plate has heat dissipation grooves. Two sets of heat conduction plates are installed inside the heat dissipation grooves. An installation plate is installed inside the heat dissipation grooves. A temperature detection device is installed on the top of the installation plate. Two symmetrical sliding grooves are opened at the bottom of the installation plate. A bimetallic strip is installed on one side of each sliding groove. The bimetallic strip has an arc structure to ensure that there is a margin for thermal expansion and elongation. A sliding seat is slidably connected inside each sliding groove. A connecting frame is connected inside each sliding seat. A hinge seat is connected to one end of each connecting frame. A base is installed at the bottom of the two hinge seats.

[0006] Preferably, the diameter of the locating pin is smaller than that of the support column.

[0007] Preferably, the elastic terminal is arranged in a Z-shaped elastic structure at the extended end of the encapsulation.

[0008] Preferably, the PCB board has through holes corresponding to the positioning pins, and the positioning pins pass through the through holes to achieve vertical penetration. The diameter of the through holes is larger than the outer diameter of the positioning pins, and the positioning pins float freely up and down inside the through holes. An elastic compensation gap is reserved between the bottom of the PCB board and the support surface of the fixed support column, so that the PCB board does not directly contact the fixed support column.

[0009] Preferably, the PCB board and Z-shaped elastic terminals are welded and fixed to the top of the power device module using a reflow soldering process to form an integrated assembly with floating compensation capability.

[0010] Preferably, one end of the bimetallic strip is connected to the slide, and there are through holes inside the base corresponding to the positions of the two heat-conducting plates, and the two heat-conducting plates are in contact with the bimetallic strip through the through holes.

[0011] Preferably, the heat sink is located on top of the base.

[0012] Preferably, the detection end of the temperature detection device is in contact with the heat sink.

[0013] Preferably, the bottom of the base is provided with an anti-slip pad layer.

[0014] The technical effects and advantages of this invention are as follows: In use, this invention achieves high integration of power devices. The PCB board is directly reflow soldered to the Z-shaped elastic terminals, eliminating bonding wires, reducing parasitic inductance, and lowering switching losses. A floating compensation structure is formed by positioning pins, support columns, and Z-shaped elastic terminals. The positioning pins can float up and down within the through-holes of the PCB board, and the support columns have pre-reserved gaps between themselves and the PCB to allow for terminal deformation. The Z-shaped elastic terminals compensate for assembly tolerances, ensuring the module's heat dissipation surface fits tightly against the heat sink, reducing contact thermal resistance. Simultaneously, the terminals can buffer thermal cycle stress, extending their service life. The heat dissipation base plate integrates a passive bimetallic strip heat dissipation mechanism. The bimetallic strip combines temperature measurement and heat conduction functions. After heating, its deformation raises the base via a connecting rod, automatically increasing the heat dissipation area. After cooling, it automatically resets, requiring no additional energy consumption.

[0015] In use, this invention implements a dual temperature control protection mechanism of "active and passive"; the temperature detection device on the top of the mounting plate is in direct contact with the heat sink, collecting the temperature in real time and feeding it back to the external control system. The control system can actively reduce the switching frequency or shut down the output when the temperature exceeds the threshold; at the same time, the bimetallic strip linkage mechanism, as an independent passive protection layer, can still respond automatically when the controller fails or communication is interrupted, greatly improving the safety margin of the module; the bottom of the base is equipped with an anti-slip pad to ensure the module is installed stably in a vibration environment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the encapsulation structure of the present invention; Figure 3 This is a schematic diagram of the exploded structure of the encapsulated body of the present invention; Figure 4 This is a side view of the structure of the present invention.

[0017] Figure 5 This is a schematic diagram of the heat dissipation base plate assembly of the present invention.

[0018] Figure 6 This is a first-view semi-exploded view of the heat dissipation base plate assembly of the present invention.

[0019] Figure 7 This is a second-view semi-exploded view of the heat dissipation base plate assembly of the present invention.

[0020] Figure 8 This is an internal view of the heat dissipation base plate assembly of the present invention.

[0021] The attached figures are labeled as follows: 1. Molded body; 2. Flexible terminal; 3. External heat dissipation surface; 4. PCB board; 5. Positioning pin; 6. Heat dissipation base plate assembly; 7. Support column; 8. Current-carrying heat conductor; 9. Power device body; 61. Heat sink; 62. Heat-conducting plate; 63. Heat dissipation groove; 65. Mounting plate; 66. Temperature detection device; 67. Slide; 68. Bimetallic strip; 69. Slide seat; 610. Connecting frame; 611. Hinge seat; 613. Base. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] As attached Figures 1-8 The illustrated power device module packaging structure includes: a power device module, comprising a power device body 9, elastic terminals 2, and a current-carrying heat conductor 8 encapsulated in a molding compound 1 as an integrated module. The elastic terminals 2 are arranged in a Z-shaped elastic structure at the extended end of the molding compound 1. A support post 7 is provided on the upper part of the molding compound 1, and a positioning pin 5 is provided on the upper part of the support post 7. A PCB board 4 is provided on the surface of the positioning pin 5. The top of the power device module is welded and fixed to the PCB board 4 and the Z-shaped elastic terminals 2 using a reflow soldering process to form an integrated assembly with floating compensation capability. The diameter of the positioning pin 5 is smaller than that of the support post 7. The support end face of the column 7 and the PCB board 4 are reserved with a gap as an elastic deformation compensation space. The PCB board 4 is provided with a through hole corresponding to the positioning pin 5. The positioning pin 5 passes through the through hole to achieve vertical penetration. The diameter of the through hole is larger than the outer diameter of the positioning pin 5. The positioning pin 5 floats freely up and down inside the through hole. An elastic compensation gap is reserved between the bottom of the PCB board 4 and the support surface of the fixed support column 7. The PCB board 4 does not directly contact the fixed support column 7. The PCB board 4 is welded and fixed to the elastic terminal 2. The bottom of the current-carrying heat conductor 8 is provided with an external heat dissipation surface 3. The lower part of the external heat dissipation surface 3 is threadedly connected to the heat dissipation base plate assembly 6. The heat dissipation base plate assembly 6 includes a heat dissipation plate 61 disposed at the bottom of the external heat dissipation surface 3. A heat dissipation groove 63 is formed at the bottom of the heat dissipation plate 61. Two sets of heat-conducting plates 62 are installed inside the heat dissipation groove 63. A mounting plate 65 is installed inside the heat dissipation groove 63. A temperature detection device 66 is installed on the top of the mounting plate 65, and the detection end of the temperature detection device 66 is in contact with the heat dissipation plate 61. Two symmetrical sliding grooves 67 are formed at the bottom of the mounting plate 65. A bimetallic strip 68 is installed on one side of each sliding groove 67. The bimetallic strip 68 has an arc-shaped structure to ensure sufficient thermal expansion and contraction. The two slides 67 are slidably connected to slide blocks 69 inside each slide block 69. Each slide block 69 is connected to a connecting bracket 610 inside each slide block 69. Each connecting bracket 610 is connected to a hinge seat 611 at one end. The bottom of the two hinge seats 611 is jointly mounted on a base 613. One end of a bimetallic strip 68 is connected to the slide block 69. The base 613 has through holes at the positions corresponding to the two heat conduction plates 62. The two heat conduction plates 62 are in contact with the bimetallic strip 68 through the through holes. The heat sink 61 is located on the top of the base 613. The bottom of the base 613 is provided with an anti-slip pad layer.

[0024] The base 613 has through holes corresponding to the positions of the two sets of heat conduction plates 62. One end of the bimetallic strip 68 is connected to the slide 69, and the other end passes through the through hole and directly contacts the heat conduction plate 62. The heat of the heat sink 61 is transferred to the bimetallic strip 68 through the heat conduction plate 62, so that the bimetallic strip 68 can sensitively sense the heat of the heat sink 61. Each of the two connecting brackets 610 has a hinge seat 611 connected to one end, and the two hinge seats 611 are mounted on a base 613 at their bottom ends, forming a parallelogram linkage mechanism. The function of this mechanism is to convert the small linear displacement of the slide block 69 in the slide groove 67 into a larger vertical displacement of the base 613 through the leverage effect of the hinge seat 611, thereby significantly increasing the distance between the heat sink 61 and the base 613 and improving the response amplitude of the passive thermal protection. At the same time, the symmetrical double slide groove 67 and double slide block 69 design ensures the smoothness of the lifting and lowering movement of the base 613 and prevents tilting or jamming. The detection end of the temperature detection device 66 is in direct contact with the heat sink 61, and collects the surface temperature of the heat sink 61 in real time and feeds it back to the external control system. By relying on the elastic deformation of the Z-shaped elastic terminal 2 to compensate for the assembly gap, the bottom current-carrying heat conductor 8 and the external heat dissipation surface 3 of the power device encapsulation 1 can be completely and gaplessly pressed against the heat dissipation plate 61 of the heat dissipation base plate assembly 6. All the heat generated by the power device can be completely and without dead angles conducted to the heat dissipation plate 61, and there will be no local heat accumulation. The heat is diverted through the heat dissipation plate 61 to the heat conduction plate 62 in the groove, and then directly conducted to the bimetallic strip 68 through the through hole provided in the base 613, realizing the full-area heat transfer and ensuring that the temperature sensing is lag-free. The entire transmission and lifting mechanism, including the slide 67, slide block 69, connecting frame 610, hinge seat 611, and base 613, is made of low-density, lightweight, thermally conductive alloy / engineering plastic, resulting in a small overall weight. The small thrust generated by the thermal deformation of the bimetallic strip 68 can smoothly drive the entire mechanism to slide and lift, eliminating the problems of component self-weight jamming or insufficient deformation thrust to lift the base 613. The low-temperature rebound reset is also more sensitive. The ventilation gap between the heat sink 61 and the base 613 is controlled autonomously by the deformation of the bimetallic strip 68. It does not require motor or electronic control drive and relies on the heat generated by the device itself to achieve self-adjustment of the gap, which is a passive heat dissipation protection structure.

[0025] Working principle of this invention: The power device module consists of a power device body 9, elastic terminals 2, and a current-carrying heat conductor 8, all encapsulated in a plastic package 1. The plastic package 1 not only protects the internal components from external environmental influences, but also provides a Z-shaped elastic structure for the elastic terminals 2 at their extended ends. This structure, combined with positioning pins 5 and support pillars 7, forms a floating compensation structure. The positioning pins 5 penetrate vertically through a through-hole in the PCB board 4, with the hole diameter larger than the outer diameter of the positioning pins 5, allowing them to float freely up and down within the hole. An elastic compensation gap is reserved between the support end face of the support pillar 7 and the PCB board 4, preventing direct contact between the PCB board 4 and the support pillar 7. The PCB board 4 and the Z-shaped elastic terminals 2... The assembly is fixed by reflow soldering to form an integrated assembly with floating compensation capability. During assembly, the elastic deformation of the Z-shaped elastic terminal 2 can compensate for assembly tolerances, eliminate the gap between the power module and the heat sink 61, and ensure that the heat dissipation surface is tightly attached. The PCB board 4 is vertically floating by the positioning pin 5 that can float up and down. The gap between the support column 7 and the PCB board 4 provides sufficient space for the deformation of the elastic terminal 2. During operation, the heat generated by the wafer in the power device module is conducted to the external heat dissipation surface 3 through the bottom current-carrying heat conductor 8. The current-carrying heat conductor 8 has good thermal conductivity and can quickly conduct heat from the internal device to the external heat dissipation surface 3. Heat is transferred downward from the external heat dissipation surface 3 to the heat dissipation base plate assembly 6. The heat dissipation plate 61 is set at the bottom of the external heat dissipation surface 3, and a heat dissipation groove 63 is opened below it. Heat is dissipated to the environment through natural convection or forced convection. The heat conduction plate 62 assists in horizontal heat equalization in the groove to reduce the temperature of local hot spots. The heat sink 63 also houses a mounting plate 65, on the top of which is a temperature detection device 66. The detection end contacts the heat sink 61, monitoring the module temperature in real time and feeding the signal back to the external control system. The bottom of the mounting plate 65 has two symmetrical sliding grooves 67. A bimetallic strip 68 is installed on one side of each groove 67. One end of the bimetallic strip 68 is connected to a slide block 69 and contacts the heat-conducting plate 62. The slide block 69 slides within the groove 67 and is connected to a hinge base 611 via a connecting bracket 610. Both hinge bases 611 share a common base at their bottom ends. 613. The base 613 has through holes corresponding to the positions of the two sets of heat-conducting plates 62. The heat sink 61 is located on top of the base 613. When the temperature of the heat sink 61 rises, the bimetallic strip 68 expands and contracts due to heat, pushing the slide block 69 to slide along the slide groove 67. This expansion is transmitted through the linkage mechanism of the connecting frame 610 and the hinge seat 611, causing the base 613 to rise. This increases the distance between the heat sink 61 and the base 613, increasing the effective heat dissipation area and achieving passive thermal protection. When the temperature drops, the bimetallic strip 68 rebounds, all components reset, and normal heat dissipation is restored. The bottom of the base 613 is provided with an anti-slip pad to ensure stable installation of the module in a vibration environment.

[0026] Finally, the following points should be noted: First, in the description of this invention, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can refer to mechanical connection or electrical connection, or internal connection between two components, or direct connection. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationship. When the absolute position of the object being described changes, the relative positional relationship may change. Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other. In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A packaging structure for a power device module, characterized in that: include: The power device module is a power device body (9), an elastic terminal (2) and a current-carrying heat conductor (8) packaged together by a plastic encapsulation body (1). The upper part of the plastic encapsulation body (1) is provided with a support column (7), the upper part of the support column (7) is provided with a positioning pin (5), the surface of the positioning pin (5) is provided with a PCB board (4), a gap is reserved between the support end face of the support column (7) and the PCB board (4) as an elastic deformation compensation space, the PCB board (4) is welded and fixed to the elastic terminal (2), the bottom of the current-carrying heat conductor (8) is provided with an external heat dissipation surface (3), and the lower part of the external heat dissipation surface (3) is threadedly connected to a heat dissipation base plate assembly (6). The heat dissipation base plate assembly (6) includes a heat dissipation plate (61) disposed at the bottom of the external heat dissipation surface (3). A heat dissipation groove (63) is provided at the bottom of the heat dissipation plate (61). Two sets of heat conduction plates (62) are installed inside the heat dissipation groove (63). An installation plate (65) is installed inside the heat dissipation groove (63). A temperature detection device (66) is installed on the top of the installation plate (65). Two symmetrical sliding grooves (67) are provided at the bottom of the installation plate (65). A bimetallic strip (68) is installed on one side of the interior of each of the two sliding grooves (67). The bimetallic strip (68) has an arc-shaped structure. A sliding seat (69) is slidably connected inside the interior of each of the two sliding grooves (67). A connecting frame (610) is connected inside the interior of each of the two sliding seats (69). A hinge seat (611) is connected to one end of each of the two connecting frames (610). A base (613) is installed at the bottom of the two hinge seats (611).

2. The packaging structure of a power device module according to claim 1, characterized in that: The diameter of the positioning pin (5) is smaller than that of the support column (7).

3. The packaging structure of a power device module according to claim 1, characterized in that: The elastic terminal (2) is arranged in a Z-shaped elastic structure at the extension end of the encapsulation body (1).

4. The packaging structure of a power device module according to claim 1, characterized in that: The PCB board (4) has a through hole with a corresponding positioning pin (5). The positioning pin (5) passes through the through hole to achieve vertical penetration. The diameter of the through hole is larger than the outer diameter of the positioning pin (5). The positioning pin (5) floats freely up and down inside the through hole. An elastic compensation gap is reserved between the bottom of the PCB board (4) and the support surface of the fixed support column (7). The PCB board (4) does not directly contact the fixed support column (7).

5. The packaging structure of a power device module according to claim 1, characterized in that: The top of the power device module is welded and fixed to the PCB board (4) and the Z-shaped elastic terminal (2) using a reflow soldering process to form an integrated assembly with floating compensation capability.

6. The packaging structure of a power device module according to claim 1, characterized in that: One end of the bimetallic strip (68) is connected to the slide (69). The base (613) has through holes at the positions corresponding to the two heat-conducting plates (62), and the two heat-conducting plates (62) are in contact with the bimetallic strip (68) through the through holes.

7. The packaging structure of a power device module according to claim 1, characterized in that: The heat sink (61) is located on top of the base (613).

8. The packaging structure of a power device module according to claim 1, characterized in that: The detection end of the temperature detection device (66) is in contact with the heat sink (61).

9. The packaging structure of a power device module according to claim 1, characterized in that: The bottom of the base (613) is provided with an anti-slip pad layer.

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