Packaging structure and packaging method of power module

Abstract

The embodiment of the present application discloses a packaging structure and packaging method of a power module, which are applied in the automotive field. The packaging structure includes a power module and a liquid-cooled radiator. The power module includes a power module body, a metal base plate and a heat dissipation fin tube, the front of the metal base plate is connected to the power module body, and the back of the metal base plate is connected to the heat dissipation fin tube. Among them, the metal base plate has a protrusion protruding from the power module body. There are multiple grooves on the liquid flow pipeline of the liquid-cooled radiator, and there is a cavity between two adjacent grooves in the multiple grooves, and the cavity is used to connect the two adjacent grooves. The power module body is overlapped on the groove, the back of the protrusion is in contact with the edge surface of the groove, and the heat dissipation fin tube is placed in the groove. Among them, there is a front weld on the front of the protrusion, and there is a back weld on the back of the metal base plate except the back of the protrusion. The front weld and the back weld are used to form a welding sealing ring.

Description

Technical Field

[0001] The embodiments of the present application relate to the automotive field, and in particular to a packaging structure and a packaging method of a power module. Background Art

[0002] In response to environmental issues, the carbon neutrality goal has led to the vigorous development of the electric vehicle industry, and as a result, the demand for modules has shown explosive growth. The power modules provided by module suppliers need to have higher power density, lower cost and longer service life in order to save resources and improve industrial efficiency.

[0003] In view of the power density of power modules, module suppliers began to package power modules with heat sinks, and sealed the power modules and heat sink liquid channels by welding or sealing and crimping to form a whole. Common methods include: using laser local high-energy heating to establish a molten pool and welding area. Or add a sealing ring between the power module and the heat sink, and use screws and pressing blocks to press the module onto the heat sink, and finally form a sealed heat dissipation liquid channel.

[0004] However, in the above two solutions, the former cannot form a continuous laser processing light path because the power module usually needs to extend the power pins from the side, and the latter cannot provide a high-reliability sealing liquid channel because the sealing ring may harden and crack due to aging, or the pressing surface of the power module and the heat sink may deform to cause a gap, eventually leading to local leakage and causing the risk of electrical short circuit. Therefore, when the power module and the heat sink are assembled, how to provide a more complete and reliable sealing liquid channel becomes an urgent problem to be solved. Summary of the invention

[0005] The embodiment of the present application provides a packaging structure and packaging method of a power module, wherein the power module body is overlapped on the groove of the radiator liquid flow pipe, so that the protrusion of the metal bottom plate protruding from the power module body contacts the edge surface of the groove, and the heat dissipation fin tube is placed in the groove. Then, laser welding is used to form a welding sealing ring. In this way, a complete sealed liquid passage can be formed between the power module and the radiator, thereby improving the sealing reliability of the packaging structure.

[0006] A first aspect of an embodiment of the present application provides a packaging structure of a power module, including:

[0007] In order to improve the power density of the power module, it can be packaged together with the liquid cooling radiator to form a complete packaging structure. Among them, the power module is composed of three parts: the power module body, the metal base plate and the heat dissipation fin tube. The front of the metal base plate is connected to the power module body, the back is connected to the heat dissipation fin tube, and the metal base plate protrudes from the power module body. The liquid cooling radiator is composed of a liquid inlet, a liquid flow pipeline and a liquid outlet. At the same time, there are multiple grooves on the liquid flow pipeline, and there are cavities between adjacent grooves, and the cavities connect multiple grooves. When packaging the power module, it is necessary to overlap the power module body on the groove, the protrusion of the metal base plate contacts the edge of the groove, and the heat dissipation fin tube is placed in the groove. Then weld the front weld on the front of the protrusion, and weld the back weld on the back of the metal base plate except the back of the protrusion. The front weld and the back weld form a welding sealing ring, and finally form a complete and integrated packaging structure.

[0008] In the above packaging structure, the power module body is placed on the upper part of the groove, and the heat dissipation fin tube is inserted into the groove to directly contact the heat dissipation liquid, which can greatly improve the heat dissipation function of the power module. At the same time, the metal base plate has a protrusion protruding from the power module body, which provides a welding surface for front welding. By combining front welding with back welding, a welding sealing ring is formed, and a complete sealing structure can be obtained without a sealing ring, avoiding the occurrence of local leakage. A complete sealed liquid passage is formed between the power module and the radiator, which improves the sealing reliability of the entire packaging structure.

[0009] In an optional embodiment, there is a power pin on the side of the power module body, which is the port for connecting the power module to the external circuit. The existence of the power pin will bring great difficulties to the front welding, so the protrusion of the metal base plate (the welding surface for front welding) is located on the side other than the side where the power pin is located. The side where the power pin is located is sealed by back welding. In this way, the protrusion is welded by the front side, and the side of the power pin is welded by the back side to form a welding sealing ring. The difficulty of welding is greatly reduced.

[0010] In an optional embodiment, the power module body is a square structure, the protrusion is located on the first side and the second side of the power module body which are parallel to each other, and the power pin is located on the third side and the fourth side which are perpendicular to the first side and the second side. That is, the front welds formed in the end are parallel to each other, the back welds are parallel to each other, and the front welds and the back welds are perpendicular to each other, so that the front welds and the back welds form a weld overlap area, so as to form a complete welding sealing ring.

[0011] In an optional embodiment, the back weld exists on the back of the metal base plate and is formed by back welding. It is understandable that the side where the power pin is located cannot be welded from the front, so the weld formed by back welding exists in the first part and the second part of the back of the metal base plate, the first part is adjacent to the third side, and the second part is adjacent to the fourth side. The first part and the second part overlap with the back of the protrusion respectively to form a welding sealing ring. This can reduce the difficulty of welding and improve welding efficiency.

[0012] In an optional embodiment, a reinforcing rib is further provided on the front side of the protrusion, and the reinforcing rib is used to enhance the strength of the protrusion, ensure the welding strength required for front welding, and improve welding efficiency.

[0013] In an optional embodiment, the width of the protrusion, the first part and the second part on the back of the metal base plate are both between 4 and 12 mm, and the thickness is both between 0.5 and 4 mm, so as to ensure the welding quality and improve the welding reliability.

[0014] In an optional embodiment, whether it is a front weld or a back weld, the width of the weld needs to be greater than or equal to 2 mm to ensure the reliability of the welding.

[0015] In an optional embodiment, the heat dissipation fin tubes are distributed in a rectangular shape on the back side of the metal bottom edge, which facilitates the distribution of the back weld and makes it easier to form a welding sealing ring. The heat dissipation fin tubes can be circular fin tubes, conical fin tubes or diamond fin tubes, providing a variety of fin tube options for the power module.

[0016] A second aspect of an embodiment of the present application provides a packaging method for a power module, comprising:

[0017] The power module is composed of three parts: the power module body, the metal base plate and the heat dissipation fin tube. The front of the metal base plate is connected to the power module body, and the back is connected to the heat dissipation fin tube, and the metal base plate protrudes from the power module body. The liquid-cooled radiator is composed of a liquid inlet, a liquid flow pipeline and a liquid outlet. At the same time, there are multiple grooves on the liquid flow pipeline, and there are cavities between adjacent grooves, and the cavities connect multiple grooves. When packaging the power module, the power module body is placed on the groove on the liquid flow pipeline so that the back of the protrusion of the metal base plate contacts the edge surface of the groove, and the heat dissipation fin tube included in the power module is placed in the groove. Then the power module and the liquid-cooled radiator are fixed together by a clamp, and the front weld is processed on the front of the protrusion, and the back weld is processed on the back of the metal base plate except the back of the protrusion. Finally, the front weld and the back weld form a welding sealing ring.

[0018] In the above packaging structure, the power module body is placed on the upper part of the groove, and the heat dissipation fin tube is inserted into the groove to directly contact the heat dissipation liquid, which can greatly improve the heat dissipation function of the power module. At the same time, the metal base plate has a protrusion protruding from the power module body, which provides a welding surface for front welding. By combining front welding with back welding, a welding sealing ring is formed, and a complete sealing structure can be obtained without a sealing ring, avoiding the occurrence of local leakage. A complete sealed liquid passage is formed between the power module and the radiator, which improves the sealing reliability of the entire packaging structure.

[0019] In an optional embodiment, the power module body further includes power pins, and the power pins are located on other side surfaces of the power module body except the side surface where the protrusion is located.

[0020] In an optional embodiment, the protrusion is located on the first side and the second side of the power module body, and the power pin is located on the third side and the fourth side of the power module body, wherein the plane where the first side is located is parallel to the plane where the second side is located, the plane where the third side is located is parallel to the plane where the fourth side is located, and the plane where the first side is located is perpendicular to the plane where the third side is located.

[0021] In an optional embodiment, the back weld exists in a first portion and a second portion of the back side of the metal bottom plate, the first portion is adjacent to the third side, and the second portion is adjacent to the fourth side. The first portion and the second portion overlap with the back side of the protrusion respectively.

[0022] In an optional embodiment, before processing the front weld on the front side of the protrusion, at least one reinforcing rib needs to be provided on the front side of the protrusion, and the reinforcing rib is used to increase the strength of the protrusion.

[0023] In an optional embodiment, the width of the protrusion, the first part and the second part are all between 4 and 12 mm, and the thickness of the protrusion, the first part and the second part are all between 0.5 and 4 mm.

[0024] In an optional embodiment, the width of the front weld and the back weld is greater than or equal to 2 mm.

[0025] In an optional embodiment, the heat dissipating fin tubes are distributed in a rectangular shape, and the heat dissipating fin tubes are circular fin tubes, conical fin tubes or diamond fin tubes.

[0026] In an optional embodiment, the front weld and the back weld are processed by high-energy laser processing, stir friction welding processing or ultrasonic welding processing.

[0027] A third aspect of an embodiment of the present application provides an inverter, comprising the packaging structure of the power module described in the first aspect and any implementation manner of the first aspect, wherein the inverter is used to convert direct current into alternating current.

[0028] The fourth aspect of the embodiment of the present application provides an AC motor drive system, which includes a DC power supply, an inverter and an AC motor. One end of the inverter is connected to the DC power supply, and the other end is connected to the AC motor. The inverter includes the packaging structure of the power module described in the first aspect and any embodiment of the first aspect. The inverter is used to convert the DC power provided by the DC power supply into AC power, and provide the AC power to the AC motor to control the speed of the AC motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a packaging structure of a power module provided in an embodiment of the present application;

[0030] Figure 2A A schematic diagram of a packaging structure of a power module provided in an embodiment of the present application;

[0031] Figure 2B A schematic diagram of the structure of a power module provided in an embodiment of the present application;

[0032] Figure 3A A top view of a packaging structure of a power module provided in an embodiment of the present application;

[0033] Figure 3B A bottom view of a packaging structure of a power module provided in an embodiment of the present application;

[0034] Figure 3C A front view of a packaging structure of a power module provided in an embodiment of the present application;

[0035] Figure 4A A top view of a power module provided in an embodiment of the present application;

[0036] Figure 4B A bottom view of a power module provided in an embodiment of the present application;

[0037] Figure 5 A bottom view of a packaging structure of a power module provided in an embodiment of the present application;

[0038] Figure 6 A bottom view of another power module provided in an embodiment of the present application;

[0039] Figure 7 A schematic diagram of a packaging structure of a power module provided in an embodiment of the present application;

[0040] Figure 8 A schematic flow chart of a power module packaging method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The embodiment of the present application provides a packaging structure and packaging method of a power module, wherein the power module body is overlapped on the groove of the radiator liquid flow pipe, so that the protrusion of the metal bottom plate protruding from the power module body contacts the edge surface of the groove, and the heat dissipation fin tube is placed in the groove. Then, laser welding is used to form a welding sealing ring. In this way, a complete sealed liquid passage can be formed between the power module and the radiator, thereby improving the sealing reliability of the packaging structure.

[0042] The technical terms used in the embodiments of the present invention are only used to illustrate specific embodiments and are not intended to limit the present invention. In this article, the singular forms "a", "the" and "said" are used to include plural forms at the same time, unless the context clearly states otherwise. Further, the terms "including" and / or "comprising" used in the specification refer to the presence of the features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements and / or components.

[0043] The corresponding structures, materials, acts, and equivalents of all means or steps and function elements in the appended claims, if any, are intended to include any structure, material, or act for performing that function in combination with other explicitly claimed elements. The description of the present invention is presented for purposes of example and description, but is not intended to be exhaustive or to limit the invention to the form disclosed.

[0044] With the introduction of the concept of carbon neutrality, the electric vehicle industry continues to develop. Compared with traditional fuel vehicles and hybrid electric vehicles, pure electric vehicles lack engines and start-stop systems, but have a large number of power electronic devices such as batteries, motors, electronic control core components, electric air-conditioning drives, and on-board chargers. These devices can convert the electric energy stored in the power battery into the electric energy required by the drive motor, on-board low-voltage electrical equipment, or air-conditioning motor, and the control and conversion of electric energy cannot be separated from power semiconductors.

[0045] The huge demand for power semiconductors in electric vehicles has promoted the development of power semiconductor integration technology, and the power module is the product of its development. The power module refers to a module formed by encapsulating power electronic devices according to a certain functional combination. Different power modules play different roles in different circuit systems, such as voltage conversion, inversion, and frequency conversion. Exemplarily, the electric drive power module is used as a driving device, and the power electronic device it includes is mainly an insulated gate bipolar transistor (IGBT). IGBT has the characteristics of small conduction voltage drop, high withstand voltage, and high output power. It is a power device that is turned on by voltage drive. When the electric drive power module is applied to the inverter, the direct current provided by the battery can be converted into alternating current, and then transmitted to the motor according to the principle of electromagnetic induction. The motor then converts the electrical energy into mechanical energy output power to drive the wheels forward.

[0046] The power module will inevitably generate heat during operation. Therefore, the design of the power module must first consider the transmission efficiency, reduce power consumption as much as possible, and improve transmission performance. At the same time, the heat accumulation caused by high voltage and high current in the power module is likely to cause the power device to burn out or break down. Therefore, the heat dissipation of the power module must also be considered to improve the heat dissipation performance. At the same time, the arrangement of the power module and other equipment must also meet the compact design.

[0047] Based on the above design requirements, in order to further improve the power density of the power module, nowadays more and more manufacturers choose to combine the power module and the radiator into a whole. Usually, electric vehicles use liquid cooling radiators. Connecting the power module and the liquid cooling radiator together can greatly improve the heat dissipation performance of the power module and make the vehicle structure more compact. Specifically, the power module and the radiator liquid channel can be sealed into a whole by welding technology or sealing crimping. The following is a brief introduction.

[0048] Figure 1A schematic diagram of the structure of a packaging structure of a power module provided in an embodiment of the present application. Generally, although the integrated welding method has high reliability, many power module chips have a plastic-encapsulated shell and cannot withstand excessively high temperatures. Therefore, a commonly used welding method is to use a laser for local high-energy heating to establish a molten pool and a welding area. However, laser welding requires a complete and closed processing path to ensure that the laser is not blocked, and the power module chip needs to extend the pins from the side because of the connection requirements of the power pins and the power busbar, which makes it impossible to process locally. Therefore, the radiator needs to be opened into two parts, and the power module chip and the frame of the radiator are first welded together, and then the liquid channel and cover plate of the radiator are welded to it to form a whole. It should be noted that during the entire process of laser processing, the accumulation of heat needs to be controlled to ensure that the power module chip is not damaged by excessive temperature.

[0049] Specifically, Figure 1 As shown in the figure, there is a heat sink on the back of the power module chip. The exposed metal around the heat sink is overlapped with the frame of the liquid cooling radiator, and the two are welded together by the first laser welding. Then the frame of the radiator and the cover of the radiator are welded together by the second laser welding. After welding the frame and the cover, the liquid outlet and the liquid inlet are welded to the cover to complete the welding process.

[0050] The use of laser welding to form a complete seal has high requirements for processes and parameters, and defects such as pores and sand holes are easily generated during the welding process. In the above welding structure, since multiple laser weldings are required, the risk of welding defects will be greatly increased. At the same time, the radiator is divided into multiple parts. When assembled into a sealed whole, the welding distance is too long, there are too many welds, it is difficult to fix in the middle, and the process deformation is difficult to control, which will affect the reliability of the welding structure and make the welding process very complicated.

[0051] Another commonly used method is to use sealing and crimping to seal the power module and the heat sink liquid channel to form a whole. Specifically, the metal base plate of the power module protrudes from the power module body. When packaging, first add a sealing ring between the metal base plate and the sealing ring groove of the heat sink structure, and then use screws or pressing plates to connect the power module and the heat sink together, so that the sealing ring is tightly pressed on the power module and the heat sink to form a sealed liquid channel.

[0052] In the above structure, the sealing ring is squeezed and deformed. Although it can withstand a certain pressure to complete the sealed package, the aging of the sealing ring will cause the sealing ring to harden and crack, thereby generating gaps, or the deformation of the radiator will generate gaps. The final result is local leakage, and the sealing liquid channel cannot be obtained, causing the risk of electrical short circuit. At the same time, the power module chip or the radiator will also be deformed during use, resulting in the release of pressure in the sealing part, creating the risk of liquid and gas leakage. At the same time, the loosening of the pressure block and the screw fastening device will also lead to insufficient sealing compression, resulting in the risk of liquid and gas leakage. Therefore, the reliability of the sealing structure obtained by using the sealing ring is very low. How to package the power module and the radiator to obtain a reliable sealing structure has become an urgent problem to be solved.

[0053] The packaging structure and packaging method of a power module in the embodiment of the present application achieve the purpose of completing the packaging by using one laser welding (front and back sides are processed simultaneously or separately) by modifying the structure of the power module and the heat sink. In this way, the power module and the heat sink can be packaged into a whole by using a smaller length and number of welds. After welding, a complete and reliable sealed liquid passage can be formed between the power module and the heat sink, thereby improving the sealing performance of the entire welding structure and greatly reducing the risk of liquid and gas leakage.

[0054] Figure 2A A schematic diagram of a packaging structure of a power module provided in an embodiment of the present application is shown in FIG. Figure 2A As shown, the power module body 201 is a rectangular parallelepiped, and the two ends of the wide side include power terminals 202 for connecting to the external circuit system. The back of the power module body 201 is connected to a metal base plate, and the length of the wide side of the metal base plate is greater than the length of the wide side of the power module body 201, which will cause the metal base plate to have a protrusion 204 protruding from the power module body 201, that is, both sides of the long side of the power module body 201 have exposed protrusions 204, and the protrusions 204 are used to provide a welding surface for front welding.

[0055] In order to more clearly show the location of the metal base plate, Figure 2B A schematic diagram of a power module provided in an embodiment of the present application is shown in FIG. Figure 2B As shown, the power module includes a power module body 201, a power terminal 202, a metal base plate 203 and a heat dissipation fin tube 205. Figure 2B It can be seen that the metal bottom plate 203 carries the entire power module, and the metal bottom plate 203 has a protruding portion protruding from the power module body 201 , and the front side of the protruding portion is the protruding portion 204 mentioned above.

[0056] The front of the metal bottom plate 203 is connected to the power module body 201, and the back is connected to the heat dissipation fin tube 205, which is used to achieve the purpose of heat exchange to improve the heat dissipation performance of the power module. The heat dissipation fin tube 205 can be arranged in a matrix to facilitate subsequent welding to form a welding seal, and its shape can be a circular fin tube, a conical fin tube or a diamond fin tube, which is not specifically limited.

[0057] The heat sink 206 is an integrated structure formed by brazing, machining and other processes in advance. The heat sink 206 contacts the heat sink fin tubes of the power module through the heat dissipation liquid flowing in the liquid flow channel, thereby achieving heat exchange. The heat sink includes a liquid flow channel, a liquid outlet and a liquid inlet. Figure 2A It can be seen that the liquid outlet, the liquid inlet and the liquid flow channel are an integrated structure, and except for the groove 207 on the liquid flow channel, other places are closed structures. Among them, the groove 207 has a certain depth, and there is a cavity between two adjacent grooves, so that the grooves 207 and the grooves 207 are connected to each other, which is convenient for the flow of heat dissipation liquid. The function of the groove 207 is to assemble the radiator 206 and the power module together. Specifically, it is necessary to overlap the power module body 201 on the upper part of the groove 207, so that the protrusion 204 contacts the edge surface of the groove 207, and the heat dissipation fin tube 205 is just inserted into the groove 207 of the liquid flow channel, thereby forming a complete embedded combined structure. Among them, the combined structure is as follows Figure 3A , Figure 3B and Figure 3C As shown, Figure 3A It is a top view of the embedded composite structure. Figure 3B This is a bottom view of the embedded structure. Figure 3C It is the main view of the embedded combined structure.

[0058] After the embedded combined structure is overlapped, it is necessary to use welding technology to weld it into a complete sealing structure. Before the introduction, it is stipulated that in the power module structure, one side of the metal base plate 203 connected to the heat dissipation fin tube 205 is the back side of the metal base plate 203, and one side of the metal base plate 203 connected to the power module body 201 is the front side of the metal base plate 203. It can be understood that in the following embodiments, the description of the front and back sides conforms to the above provisions and will not be repeated in detail.

[0059] During the welding process, the power module and the heat sink 206 need to be fixed from the front side. It is understandable that the two sides of the power module body 201 with the power terminals 202 cannot provide the welding surface required for the front welding. Therefore, the welding surface for the front welding is the protrusion 204 protruding from the power module body 201. Taking a power module as an example, Figure 4A A top view of a power module provided in an embodiment of the present application is shown in FIG. Figure 4A As shown, in the top view, the third side and the fourth side of the power module body 201 both have power terminals 202, and the third side and the fourth side of the power module body 201 have protrusions 204 of the metal bottom plate 203. At this time, the protrusion 204 needs to be used as the welding surface for front welding, and the front weld is welded by welding methods such as high-energy laser heating. It can be understood that parallel welds can be welded on the protrusions 204 on the third side and the fourth side, and the number of welds on each side can be one or more, which is not specifically limited.

[0060] It is understandable that the parallel welds here do not mean absolute parallelism, but refer to the consistent direction of the two welds, the purpose of which is to eventually form a sealing ring. Therefore, the non-parallel welds and the bending of the weld lines that occur during the welding process can be included in the scope of the parallel welds, and only the welds that are easy to process on the front side need to be formed. At the same time, the position of the front processing is affected by the distribution position of the power terminal 202. Therefore, if the power terminal 202 on the power module body 201 is only distributed on one side, then the metal bottom plate 203 can have three protrusions protruding from the other three sides, that is, except for the side with the power terminal 202, the other three sides all have protrusions 204, so that the protrusions 204 on the three sides can be used as welding surfaces for front welding, and U-shaped front welds can be processed on the protrusions 204 on the three sides by front welding. In other words, when processing the front weld by front welding, it is only necessary to avoid one side where the power terminal 202 is distributed, and there is no specific restriction.

[0061] After the front weld is processed, the side with the power terminal 202 is not sealed, that is, the front welding fails to form a complete sealing ring. Since the power terminal 202 makes the front welding almost impossible, it is necessary to use the back welding method to seal the side with the power terminal 202 to form a complete sealing ring. Figure 4B A bottom view of a power module provided in an embodiment of the present application is shown as follows: Figure 4BAs shown, the back of the metal base plate 203 is connected with heat dissipation fin tubes 205 arranged in a matrix. The heat dissipation fin tubes 205 will be inserted into the grooves 207 of the radiator 206. The metal surface without the heat dissipation fin tubes 205 will overlap with the surface of the flow channel of the radiator 206 to provide a welding surface for back welding. Among them, the back of the metal base plate 203 includes a first part 401 and a second part 402. In the embedded structure, the first part 401 is close to the third side of the power module body 201, and the second part 402 is close to the third side of the power module body 201. The first part 401 and the second part 402 are both in contact with the edge surface of the groove 207. Since the third side and the fourth side of the power module body 201 both have power terminals 202, the first part 401 and the second part 402 need to be processed by back welding to form a back weld, and finally the metal base plate 203 and the liquid flow pipeline are formed into a whole. From the back of the radiator 206, the back weld is as shown in FIG. Figure 5 shown.

[0062] It is understandable that in order to reduce the difficulty of the back weld, the back processed area of ​​the radiator can be thinned, as shown above. Figure 2A As shown, there are side grooves on the side of the heat sink 206, the purpose of which is to thin the welding surface on the heat sink 206, reduce the difficulty of back welding, and avoid the inability to perform back welding due to the excessive thickness of the heat sink.

[0063] Among them, the front weld processed on the front side and the back weld processed on the back side need to overlap, so as to form a sealing ring to avoid leakage. Figure 6 A bottom view of another power module provided in an embodiment of the present application, such as Figure 6 As shown, after the power module is welded on the front and back, two front welds and two back welds are formed. Among them, the fusion zone of the front weld and the back weld overlaps to form four welding overlap zones. In this way, the four welds surround a complete welding sealing ring, thereby completely sealing the groove on the heat sink 206, forming a complete sealed liquid passage between the power module and the heat sink, which can avoid the occurrence of local leakage, make the power module and the heat sink integrated, and improve the reliability of the entire packaging structure.

[0064] After welding is completed, the Figure 7 The package structure shown, Figure 7A schematic structural diagram of a packaging structure of a power module provided in an embodiment of the present application includes: a power module 701, a liquid inlet 702, a liquid outlet 703, and a liquid flow pipeline 704. Among them, the heat dissipation fin tube included in the power module 701 is embedded in a groove on the liquid flow pipeline 704. The groove is sealed by welding technology, and the packaging structure has a completely closed liquid flow pipeline 704. When the radiator in the packaging structure is working, the cooling liquid flows in from the liquid inlet 702, passes through the liquid flow pipeline 704, and finally flows out to the liquid outlet 703. The direction indicated by the arrow in the figure is the liquid flow direction. Among them, the heat dissipation fin tube is in direct contact with the heat dissipation liquid, and the heat is taken away by the flowing liquid, so that the effect of quickly cooling the power module 701 can be achieved, and the heat dissipation performance of the power module 701 can be improved.

[0065] In order to ensure the embedded combination of power module and heat sink, the material requirements for each part are introduced below:

[0066] First, the material of the metal base plate corresponding to the power module can be copper Cu, aluminum Al or aluminum silicon carbide AlSiC, copper silicon carbide, aluminum diamond, etc. In a preferred manner, the thickness of the metal base plate needs to be controlled between 1 mm and 5 mm. Optionally, the outer surface of the metal base plate can be plated with aluminum, copper or nickel.

[0067] Secondly, in order to ensure that the front welding has sufficient welding surface, the size of the protrusion protruding from the power module body is also required. Optionally, the width of the protrusion on each side must be greater than 2 mm, and the thickness of the protrusion on each side needs to be between 0.5 mm and 4 mm. If the protrusion is too thick, it will increase the difficulty of front welding. Ensuring that the thickness is between 0.5 mm and 4 mm can reduce the difficulty of front welding and improve welding efficiency.

[0068] The heat dissipation fin tubes installed on the back of the metal base plate are distributed in a rectangular shape, and the shape of the heat dissipation fin tubes can be in various forms, including circular fin tubes, tapered fin tubes or diamond fin tubes, which are not specifically limited. However, since the heat dissipation fin tubes need to be embedded in the grooves on the flow channel pipes of the liquid cooling radiator, the size of the grooves needs to match the size of the matrix heat dissipation fin tubes. Specifically, the size of the groove is slightly larger than the size of the rectangle corresponding to the heat dissipation fin tube. Preferably, the length and width of the groove are 0.2 mm to 1 mm larger than the length and width of the rectangle, respectively. The depth of the groove is 0.05 mm to 0.3 mm deeper than the height of the heat dissipation fin tube, so that the heat dissipation fin can be completely embedded in the groove. At the same time, when the groove is filled with heat dissipation liquid, the heat dissipation liquid just immerses the heat dissipation fin tube. If the depth of the groove is too deep, when the groove is filled with heat dissipation liquid, a part of the heat dissipation liquid cannot contact the heat dissipation fin tube, which will cause a waste of part of the heat dissipation liquid. Therefore, the depth of the design groove is slightly deeper than the height of the heat dissipation fin tube, which can save heat dissipation liquid and improve heat dissipation efficiency.

[0069] The frame of the liquid cooling radiator can be Al, Cu, etc., and the surface of the liquid flow pipe can be Al of the main body, or nickel can be electroplated on the main body, and there is no specific limitation. Among them, the part that overlaps with the functional module for back welding needs to ensure that its width is greater than 2 mm, that is, the liquid cooling radiator needs to provide a sufficiently large welding surface, and the welding surface needs to be thinned so that the thickness can be between 0.5 and 4 mm to reduce the difficulty of back welding.

[0070] The protrusion on the metal bottom plate needs to contact the edge of the groove on the liquid flow pipe, which is also the welding surface for front welding. Therefore, the thickness of the metal layer of the liquid cooling radiator at the position corresponding to the edge surface needs to be between 1 mm and 3 mm. In order to ensure that the welding surface has sufficient strength support during welding, one or more reinforcing ribs can also be set at this position to improve the strength of the material and meet the welding requirements. However, it should be noted that the reinforcing ribs do not affect the flow of the liquid in the radiator, and the cooling liquid must flow smoothly.

[0071] During the welding process, preferably, the front weld can reach the vertex edge of the power module metal base plate, and the back weld can also reach the vertex edge of the module, so that the length of the weld peak is longer and the sealing is better. Among them, the width of the weld needs to be greater than 2 mm, and the depth of the weld needs to reach half of the thickness of the welding surface, so that the sealing reliability of the welding structure can be improved.

[0072] In the packaging structure of the power module, the power module corresponds to a metal base plate, and a heat dissipation fin tube is installed on the back of the metal base plate. The heat dissipation fin tube can be embedded in the groove on the flow channel of the liquid cooling radiator, and the protrusion included in the metal base plate overlaps the liquid flow channel (the edge surface of the groove), so that the power module and the liquid cooling radiator can be packaged as a whole by a welding method combining front welding and back welding, and a complete and reliable sealed liquid passage is formed between the power module and the liquid cooling radiator. At the same time, the combination of front welding and back welding can avoid the welding difficulty caused by the presence of the power terminal, and the liquid cooling radiator is a structure that is closed except for the groove, the liquid inlet and the liquid outlet. In this way, it only needs to be welded around the groove, and the welding distance is small, so the risks of welding heat effect, welding deformation, welding defects, etc. are reduced. Therefore, the sealing performance of the entire welding structure is strong, which will greatly reduce the risk of liquid and gas leakage and processing costs.

[0073] Figure 8 A schematic diagram of a packaging method for a power module provided in an embodiment of the present application is shown in FIG. Figure 8 As shown, the packaging method includes the following steps:

[0074] 801. Place the power module on a groove on a liquid flow pipe included in a liquid cooling radiator.

[0075] The power module includes a power module body, a metal base plate and heat sink fins, wherein the body has power terminals, the front of the metal base plate is connected to the power module body, and the back is connected to the heat sink fins. The size of the metal base plate is larger than that of the power module body, and there is a protrusion protruding from the power module body. For the specific structure, please refer to the above Figures 2A to 7 The contents of the power module in the illustrated embodiment are not described in detail here.

[0076] The structure of the liquid cooling radiator matches that of the power module. The liquid cooling radiator includes a liquid inlet, a liquid outlet, and a liquid flow pipe. There is a groove on the liquid flow pipe, which is used to place the heat dissipation fin tube of the power module. At the same time, there is a cavity between two adjacent grooves, which is used to connect multiple grooves to provide a circuit for the heat dissipation liquid. It can be understood that except for the grooves, the liquid outlet, and the liquid inlet, the other parts of the liquid cooling radiator are closed. For the specific structure, please refer to the above Figures 2A to 7 The contents of the radiator in the illustrated embodiment will not be described in detail here.

[0077] When assembling the power module and the liquid-cooled radiator, the power module body needs to be placed on the groove so that the heat dissipation fin tube is just embedded in the groove, and then the edge of the groove is sealed using welding technology. The power module and the liquid-cooled radiator can be welded into a whole to obtain a sealed liquid passage.

[0078] 802. Fix the power module and the liquid cooling radiator using a clamp.

[0079] After placing the power module, you need to use a clamp to fix the power module and the liquid cooling radiator. This step is to prepare for the welding step. Fixing the position with a clamp can prevent displacement during the welding process and improve the accuracy of welding.

[0080] 803. On the protruding portion of the metal base plate, a front weld is processed by front welding.

[0081] Specifically, the exposed metal bottom plate (protrusion) overlaps the edge surface of the groove on the liquid flow pipeline, so that the protrusion can be used as the welding surface for front welding, and the front weld can be formed by front welding. Among them, the width of the protrusion on each side needs to be greater than 2 mm to ensure that there is a large enough welding surface for processing. At the same time, the thickness of the protrusion needs to be between 0.5 mm and 4 mm to ensure the strength required for welding. If necessary, one or more reinforcing ribs can be set on the protrusion to increase the strength of the protrusion and improve the strength of the welding surface of the front welding.

[0082] 804. According to the position of the front weld, a back weld is processed on the first part and the second part of the back side of the metal base plate.

[0083] Since the power module has power terminals, it is difficult to perform front welding on the side with the power terminals. Therefore, a back welding method can be used to form a sealing ring. In an exemplary embodiment, the power terminals are located on the third side and the fourth side of the power module body, and the protrusion is located on the first side and the second side of the power module body. The bottom surface of the metal base plate has a first part and a second part. Among them, the first part is close to the third side, the second part is close to the fourth side, and there is no heat dissipation fin tube on the first part and the second part. At this time, the back weld can be processed on the first part and the second part in the direction from the liquid flow pipeline to the metal base plate, and it is necessary to ensure that the formed back weld overlaps with the front weld on the protrusion, so as to form a complete welding sealing ring. That is, the groove on the liquid flow pipeline is sealed by the power module, and the heat dissipation fin tube of the power module is placed in the groove. In this way, while the power module and the radiator are combined into a whole, a completely closed liquid flow path is provided, and the heat dissipation fin tube is directly in contact with the heat dissipation liquid. The heat dissipation liquid can quickly carry the heat generated by the power module, thereby improving the heat dissipation capacity of the power module.

[0084] Exemplarily, the protrusions on each side, serving as the welding surface for front welding, should preferably have a width greater than 2 mm to ensure that the welding surface is large enough, while the thickness needs to be between 0.5 mm and 4 mm to ensure the strength required for welding.

[0085] Among them, the width of the front weld and the back weld needs to be at least 0.5 mm, so as to ensure the reliability of the sealing ring, greatly reduce the occurrence of power module short circuit caused by liquid and gas leakage, and improve the safety of the entire packaging system.

[0086] At the same time, in the above process, whether it is front welding or back welding, the welding processing method can be high-energy laser processing, stir friction processing or ultrasonic welding processing, and there is no specific limitation. At the same time, ultrasonic testing technology can also be used after welding to detect whether the welding surface is complete to ensure the airtightness and structural strength of the entire result.

[0087] In the above-mentioned packaging method of the power module, the power module corresponds to a metal base plate, and a heat dissipation fin tube is installed on the back of the metal base plate. The heat dissipation fin tube can be embedded in the groove of the radiator, and the metal base plate is overlapped on the edge surface of the groove, and then a sealing ring is combined by the front weld of the front welding and the back weld of the back welding, so as to form a complete and reliable sealed liquid passage between the power module and the radiator. Among them, the use of both front welding and back welding can avoid the welding difficulty caused by the existence of the power terminal, and the radiator is a whole, and the rest of the places except the groove are closed structures, so only welding is needed around the groove, the welding distance is small and the welding risk is low, so the sealing performance of the entire welding structure is strong, which will greatly reduce the risk of liquid and gas leakage.

[0088] The present application also provides an inverter, including the above Figures 2A to 7 The packaging structure of the power module shown in any one of the illustrated embodiments, the inverter can convert direct current into alternating current, and can be used in various frequency conversion, rectification, inversion, or control circuits, without specific limitation.

[0089] The embodiment of the present application also provides an AC motor drive system, which includes a DC power supply, an inverter and an AC motor. One end of the inverter is connected to the DC power supply, and the other end is connected to the AC motor. The inverter includes the above Figures 2A to 7 The packaging structure of the power module shown in any one of the embodiments shown. The inverter is used to convert the DC power provided by the DC power supply into AC power, and provide the AC power to the AC motor to control the speed of the AC motor.

[0090] The technical terms used in the embodiments of the present invention are only used to illustrate specific embodiments and are not intended to limit the present invention. In this article, the singular forms "a", "the" and "said" are used to include plural forms at the same time, unless the context clearly states otherwise. Further, the terms "including" and / or "comprising" used in the specification refer to the presence of the features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements and / or components.

[0091] The corresponding structures, materials, acts, and equivalents of all means or steps and function elements in the appended claims, if any, are intended to include any structure, material, or act for performing that function in combination with other explicitly claimed elements. The description of the present invention is presented for purposes of example and description, but is not intended to be exhaustive or to limit the invention to the form disclosed.

Claims

1. A packaging structure of a power module, characterized in that: The packaging structure includes: a power module and a liquid cooling radiator; The power module comprises a power module body, a metal base plate and a heat dissipation fin tube; the front side of the metal base plate is connected to the power module body, and the back side of the metal base plate is connected to the heat dissipation fin tube; wherein the metal base plate has a protrusion protruding from the power module body; There are a plurality of grooves on the liquid flow pipeline of the liquid cooling radiator, and there is a cavity between two adjacent grooves among the plurality of grooves, and the cavity is used to connect the two adjacent grooves; The power module body is overlapped on the groove, the back side of the protrusion is in contact with the edge surface of the groove, and the heat dissipation fin tube is placed in the groove; wherein, there is a front weld on the front side of the protrusion; there is a back weld on the back side of the metal base plate except the back side of the protrusion; the front weld and the back weld form a welding sealing ring.

2. The packaging structure according to claim 1, characterized in that: The power module body further includes power pins, and the power pins are located on other side surfaces of the power module body except the side surface where the protrusion is located.

3. The packaging structure according to claim 2, characterized in that: The protrusion is located at the first side surface and the second side surface of the power module body, and the power pin is located at the third side surface and the fourth side surface of the power module body; The plane where the first side surface is located is parallel to the plane where the second side surface is located, the plane where the third side surface is located is parallel to the plane where the fourth side surface is located, and the plane where the first side surface is located is perpendicular to the plane where the third side surface is located.

4. The packaging structure according to claim 3, characterized in that: The back weld exists in a first portion and a second portion of the back side of the metal base plate, the first portion is adjacent to the third side surface, and the second portion is adjacent to the fourth side surface; the first portion and the second portion overlap with the back side of the protrusion, respectively.

5. The packaging structure according to any one of claims 1 to 4, characterized in that: The packaging structure further includes at least one reinforcing rib; the reinforcing rib is arranged on the front side of the protrusion to increase the strength of the protrusion.

6. The packaging structure according to claim 4, characterized in that: The width of the protrusion, the first portion and the second portion are all between 4 and 12 mm, and the thickness of the protrusion, the first portion and the second portion are all between 0.5 and 4 mm.

7. The packaging structure according to any one of claims 1 to 4 or 6, characterized in that: The width of the front weld and the back weld is greater than or equal to 2 mm.

8. The packaging structure according to any one of claims 1 to 4 or 6, characterized in that: The heat dissipation fin tubes are distributed in a rectangular shape, and the heat dissipation fin tubes are circular fin tubes, conical fin tubes or diamond fin tubes.

9. A method for packaging a power module, characterized in that: The method comprises: The power module body included in the power module is placed on the groove on the liquid flow pipeline included in the liquid cooling radiator, so that the back side of the protruding part of the metal bottom plate included in the power module contacts the edge surface of the groove, and the heat dissipation fin tube included in the power module is placed in the groove; wherein the front side of the metal bottom plate is connected to the power module body, and the back side of the metal bottom plate is connected to the heat dissipation fin tube; the metal bottom plate has the protruding part protruding from the power module body; The power module and the liquid cooling radiator are fixed by using a clamp; a plurality of grooves are provided on the liquid flow pipeline of the liquid cooling radiator, and a cavity exists between two adjacent grooves among the plurality of grooves, and the cavity is used to connect the two adjacent grooves; Processing a front weld on the front side of the protrusion; A back weld is processed on the back side of the metal bottom plate except for the back side of the protruding portion; the front weld and the back weld form a welding sealing ring.

10. The packaging method according to claim 9, characterized in that: The power module body further includes power pins, and the power pins are located on other side surfaces of the power module body except the side surface where the protrusion is located.

11. The packaging method according to claim 10, characterized in that: The protrusion is located at the first side surface and the second side surface of the power module body, and the power pin is located at the third side surface and the fourth side surface of the power module body; The plane where the first side surface is located is parallel to the plane where the second side surface is located, the plane where the third side surface is located is parallel to the plane where the fourth side surface is located, and the plane where the first side surface is located is perpendicular to the plane where the third side surface is located.

12. The packaging method according to claim 11, characterized in that: The back weld exists in a first portion and a second portion of the back side of the metal base plate, the first portion is adjacent to the third side surface, and the second portion is adjacent to the fourth side surface; the first portion and the second portion overlap with the back side of the protrusion, respectively.

13. The packaging method according to any one of claims 9 to 12, characterized in that: Before processing the front weld on the front side of the protrusion, the method further comprises: At least one reinforcing rib is arranged on the front side of the protrusion; the reinforcing rib is used to increase the strength of the protrusion.

14. The packaging method according to claim 12, characterized in that: The width of the protrusion, the first portion and the second portion are all between 4 and 12 mm, and the thickness of the protrusion, the first portion and the second portion are all between 0.5 and 4 mm.

15. The packaging method according to any one of claims 9 to 12 or 14, characterized in that: The width of the front weld and the back weld is greater than or equal to 2 mm.

16. The packaging method according to any one of claims 9 to 12 or 14, characterized in that: The heat dissipation fin tubes are distributed in a rectangular shape, and the heat dissipation fin tubes are circular fin tubes, conical fin tubes or diamond fin tubes.

17. The packaging method according to any one of claims 9 to 12 or 14, characterized in that: The front weld and the back weld are processed by high-energy laser processing, friction stir welding or ultrasonic welding.

18. An inverter, characterized in that: The inverter comprises the packaging structure of the power module as shown in any one of claims 1 to 8, and the inverter is used to convert direct current into alternating current.

19. An AC motor drive system, characterized in that: The AC motor drive system includes a DC power supply, an inverter and an AC motor; One end of the inverter is connected to the DC power supply, and the other end of the inverter is connected to the AC motor; the inverter comprises a packaging structure of a power module as shown in any one of claims 1 to 8; The inverter is used to convert the direct current provided by the direct current power source into alternating current, and provide the alternating current to the alternating current motor to control the rotation speed of the alternating current motor.

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