Packaging structure of high-performance IPM module and manufacturing method thereof

Abstract

The invention discloses a packaging structure of a high-performance IPM module and a manufacturing method thereof, the packaging structure comprises a tube shell base, a tube shell frame, a cover plate, a power plate, a signal plate, an insulator and a pin, the material of the tube shell base is silicon aluminum; the tube shell base and the tube shell frame are welded through gold-tin solder; the power board is welded on the tube shell base; the signal plate is fixed on the tube shell base; the upper surface of the tube shell base is provided with an internal assembling area used for being matched with a power board and a signal board, a welding groove used for being matched with a tube shell frame and a welding isolation belt located between the internal assembling area and the welding groove are arranged on the upper surface of the tube shell base. According to the scheme, on one hand, the silicon-aluminum tube shell base is adopted to realize light-weight design of products, on the other hand, matched gold-tin solder is adopted to weld the tube shell base and the tube shell frame, and the welding groove and the welding isolation strip are arranged on the tube shell base to prevent molten solder from overflowing to an internal assembly area, so that the welding quality is improved. And the welding flux is prevented from flowing to the welding groove when the power board is welded with the tube shell base.

Description

Technical Field

[0001] The present invention relates to the technical field of hybrid integrated circuit packaging, and in particular to a packaging structure of a high-performance IPM module and a manufacturing method thereof. Background Art

[0002] Hybrid integrated circuits are hermetically packaged devices with high-purity nitrogen sealed inside to ensure that fragile components such as bare chips and bonding wires inside the product are completely isolated from the adverse external environment. The products have the characteristics of a wide operating temperature range, good environmental adaptability, and high reliability, and are widely used in fields with high reliability requirements.

[0003] Among them, because the product has large current flow and high heat generation, the shell base is usually made of high thermal conductivity WCu material. Although WCu material has good thermal conductivity and matches the thermal expansion coefficient of other parts of the shell, its material density is high, resulting in a heavier product weight, which is not conducive to the lightweight design of the product.

[0004] In addition, due to the large current overcurrent requirements of this type of product, a large current needs to flow between the power board and the tube shell lead wire. This type of product traditionally mainly uses thick aluminum wire bonding connection or lead welding connection to achieve electrical interconnection between the functional area on the internal substrate of the product and the tube shell pins. Both methods are not conducive to the miniaturization design of the product. Among them, for the method of using thick aluminum wire bonding, the current capacity of a single aluminum wire is limited. In order to meet the high current design requirements, more aluminum wires need to be bonded, which requires a larger area and is not conducive to the miniaturization design of the product; for the method of using thick lead welding, the lead is harder, not easy to form, and has high stress. It is difficult to achieve high-density connection in a small space, which is also not conducive to the miniaturization design of the product.

[0005] In addition, the motor drive IPM module with metal airtight package has a higher isolation and withstand voltage requirement. The traditional way to improve the isolation and withstand voltage is to design a large diameter insulator to meet the high withstand voltage requirement between the metal shell and the metal pin. Due to the large diameter of the insulator, a larger pin spacing needs to be designed, which not only increases the length, width and height of the product, but also makes it impossible to design a high-density pin output, which is not conducive to the miniaturization of the product. Summary of the invention

[0006] In view of this, the present invention provides a packaging structure of a high-performance IPM module, which can not only meet the design requirements of high current, high thermal conductivity, and high voltage resistance of the IPM module, but also realize the lightweight and miniaturized design of the product.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A packaging structure of a high-performance IPM module includes: a tube shell base, a tube shell frame, a cover plate, a power board, a signal board, an insulator and a tube pin.

[0009] The material of the tube shell base is silicon aluminum;

[0010] The tube shell base and the tube shell frame are welded by gold-tin solder;

[0011] The power board is welded on the tube shell base;

[0012] The signal board is fixed on the tube shell base;

[0013] The upper surface of the tube shell base has an internal assembly area for cooperating with the power board and the signal board, the upper surface of the tube shell base is provided with a welding groove for cooperating with the tube shell frame, and the upper surface of the tube shell base is provided with a welding isolation zone, which is located between the internal assembly area and the welding groove.

[0014] Preferably, the welding groove is lower than the internal assembly area, and the width of the welding groove is greater than the width of the tube shell frame.

[0015] Preferably, the welding groove is 0.2 mm to 0.5 mm lower than the internal assembly area, and the width of the welding groove is 0.2 mm to 0.3 mm greater than the width of the tube shell frame;

[0016] The width of the welding isolation zone is 0.15 mm to 0.3 mm.

[0017] Preferably, it also includes a preformed copper strip;

[0018] A plurality of the pins are connected to a plurality of corresponding pads of the power board through the preformed copper tape.

[0019] Preferably, the preformed copper strip comprises: a copper strip welding portion, a copper strip bending portion and a plurality of copper strip welding holes;

[0020] The plurality of copper strip welding holes are used to pass through the plurality of tube pins one by one and be welded with the plurality of tube pins one by one;

[0021] The copper strip welding portion is connected to the end of the second portion of the copper strip bending portion and is used for welding on a plurality of corresponding welding pads of the power board.

[0022] Preferably, the inner end surface of the pin is provided with a pin welding column, and the diameter of the copper strip welding hole is larger than the diameter of the pin welding column and smaller than the diameter of the pin;

[0023] The copper tape welding hole is used to pass through the pin welding column of the pin, and the copper tape welding hole is in contact with the pin welding column and welded.

[0024] Preferably, the outer end of the insulator protrudes from the outer side wall of the tube shell frame along the tube pin, and the inner end is flush with the inner side wall of the tube shell frame;

[0025] The packaging structure of the high-performance IPM module also includes: an insulating film and a high-voltage silicone gel;

[0026] The insulating film is used to be bonded to the inner side wall of the tube shell frame, and is provided with an insulating film through hole for passing the tube pin;

[0027] The high withstand voltage silicone gel is used to coat at least the edge of the insulating film and between the edge of the through hole of the insulating film and the pin.

[0028] Preferably, the number of the insulating films is two;

[0029] The two insulating films are used to be respectively bonded to two opposite inner side walls of the tube shell frame, and are each provided with a plurality of insulating film through holes for passing through a plurality of the pins on the same side one by one;

[0030] The high-voltage silicone gel is used to coat at least the edges of the two insulating films and between the edge of each through hole of the insulating film and the corresponding pin.

[0031] Preferably, each of the insulating films is provided with a plurality of insulating film slits distributed in parallel, and one side of the plurality of insulating film slits is connected one by one with the plurality of through holes of the insulating film, and the other side is connected with the upper edge or the lower edge of the insulating film;

[0032] The high withstand voltage silicone gel is also used to coat the gaps of each insulating film cut in each of the insulating films.

[0033] A method for manufacturing a packaging structure of a high-performance IPM module, used for manufacturing the packaging structure of the high-performance IPM module as described above, wherein the outer end of the insulator of the packaging structure of the high-performance IPM module protrudes from the outer side wall of the tube shell frame along the tube pin, and the inner end is flush with the inner side wall of the tube shell frame;

[0034] The packaging structure of the high-performance IPM module also includes: an insulating film and a high-voltage silicone gel;

[0035] The insulating film is used to be bonded to the inner side wall of the tube shell frame, and is provided with an insulating film through hole for passing the tube pin;

[0036] The high withstand voltage silicone gel is used to coat at least the edge of the insulating film and between the edge of the through hole of the insulating film and the pin;

[0037] The production method comprises:

[0038] S1. Provide the tube shell base, tube shell frame, cover, power board, signal board, insulator, pin, preformed copper tape, insulation film and high-voltage silicone gel;

[0039] S2, welding the tube shell base and the tube shell frame;

[0040] S3, mounting: mounting the power board on the tube shell base, mounting the power board components on the surface of the power board, inserting the copper tape welding holes of the preformed copper tape into the pin welding columns of the corresponding pins, and mounting the copper tape welding part on the corresponding pads of the power board;

[0041] S4, reflow soldering: solder the power board to the base of the tube shell, solder the power board components to the surface of the power board, and solder the copper strip soldering part to the corresponding soldering pad of the power board;

[0042] S5, completing the welding of the copper tape welding holes of the preformed copper tape and the pin welding columns of the corresponding pins;

[0043] S6, complete welding cleaning;

[0044] S7, attaching the insulating film to the inner wall of the tube shell frame;

[0045] S8, complete the assembly of the signal board, and fix the signal board assembly on the tube shell base;

[0046] S9, bonding the signal board and the power board;

[0047] S10, coating the high-voltage silicone gel on the edge of the insulating film, between the edge of the through hole of the insulating film and the pin, and between the high-voltage assembly area and the low-voltage assembly area of ​​the power board;

[0048] S11. Install the cover to complete the packaging.

[0049] It can be seen from the above technical solutions that the packaging structure of the high-performance IPM module provided by the present invention can not only meet the design requirements of high current, high thermal conductivity and high voltage resistance of the IPM module, but also realize the lightweight and miniaturized design of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 A cross-sectional view of the packaging structure of a high-performance IPM module provided by an embodiment of the present invention;

[0052] Figure 2 A schematic diagram of the inner side structure of a pin insulation structure provided by an embodiment of the present invention;

[0053] Figure 3 A cross-sectional schematic diagram of a pin insulation structure provided by an embodiment of the present invention;

[0054] Figure 4 A schematic cross-sectional view of a preformed copper strip provided in an embodiment of the present invention;

[0055] Figure 5-Figure 8 Schematic diagram of the structure of different preformed copper strips provided by embodiments of the present invention;

[0056] Fig. 9 A schematic diagram of the structure of a preformed insulating film provided in an embodiment of the present invention;

[0057] Fig.10 A schematic flow chart of a method for manufacturing a packaging structure of a high-performance IPM module provided in an embodiment of the present invention.

[0058] Among them, 11 is the tube shell base, 12 is the tube shell frame, 13 is the power board, 14 is the signal board, 15 is the preformed copper tape, 16 is the gold-tin solder, 18 is the copper tape welding part, 19 is the copper tape bending part, 20 is the copper tape welding hole, 21 is the tube pin, 22 is the cover plate, 23 is the insulating film, 24 is the high-voltage silicone gel, 25 is the welding groove, 26 is the insulating film through hole, 27 is the insulating film slit, 28 is the tube pin welding column, 29 is the insulator, and 30 is the welding isolation tape. DETAILED DESCRIPTION

[0059] The invention discloses a packaging structure of a high-performance and high-reliability IPM motor drive module, wherein a ceramic insulator, a pin and a pin welding area (pin welding column) located at the front end of the pin are arranged on a tube shell frame; a welding hole of a preformed copper strip is welded and connected to the pin welding area; a preformed insulating film is mounted on the inner wall of the tube shell frame, and is provided with through holes matching the pins and slits for the pins to pass through during installation; a high-voltage silicone gel is coated on a high-voltage isolation area inside the product and on the edge of the preformed insulating film; a copper strip welding part is welded and connected to a power board; a tube shell base and a tube shell frame are airtightly welded by gold-tin solder; the power board is welded to the tube shell base; and a signal board is fixed to the tube shell base.

[0060] The present invention realizes the high voltage resistance design requirement of miniaturized products by designing an outward convex ceramic insulator on the outside of the product, pasting a preformed insulating film on the inside of the product, and partially coating a high voltage resistance silicone gel. The use of preformed copper strips not only meets the high current demand of the product, but also realizes the miniaturized design requirement of the product. By using gold-tin to weld the silicon-aluminum base and the tube shell frame, an airtight packaging structure is formed, which not only retains the high thermal conductivity characteristics of the product tube shell base, but also replaces the heavier WCu material, thereby realizing the lightweight design of the product. In other words, the packaging structure of a high-performance, high-reliability IPM motor drive module disclosed in the present invention can not only meet the design requirements of high current, high thermal conductivity, and high voltage resistance, but also realize the lightweight and miniaturized design of the product.

[0061] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] The packaging structure of the high-performance IPM module provided by the embodiment of the present invention is as follows: Figure 1 As shown, it includes: a tube shell base 11, a tube shell frame 12, a cover plate 22, a power board 13, a signal board 14, an insulator 29 and a pin 21,

[0063] The material of the tube shell base 11 is silicon aluminum;

[0064] The tube shell base 11 and the tube shell frame 12 are welded by gold-tin solder 16;

[0065] The power board 13 is welded on the tube shell base 11;

[0066] The signal board 14 is fixed on the tube shell base 11;

[0067] The upper surface (top surface) of the tube shell base 11 has an internal assembly area for cooperating with the power board 13 and the signal board 14. The upper surface of the tube shell base 11 is provided with a welding groove 25 for cooperating with the tube shell frame 12. The upper surface of the tube shell base 11 is provided with a welding isolation zone 30, which is located between the internal assembly area and the welding groove 25.

[0068] It should be noted that the shell base 11 is made of silicon aluminum. The base material of the shell base 11 is silicon aluminum, and the composition is Al50Si50; the base material of the shell frame 12 is No. 10 steel. That is to say, in this solution, the shell base 11 uses a silicon aluminum base material made of Al50Si50. The silicon aluminum material has high strength and can be used as a shell base material. Its thermal conductivity is 140W / (mK), which can meet the high thermal conductivity requirements of medium and high power IPM modules. The thermal expansion coefficient of silicon aluminum material is 11.5×10 -6 / K, when used as a shell base, the thermal expansion coefficient of the 10# steel shell frame (13.0×10 -6 / K) matches to meet the high reliability requirements of the product. The density of the silicon aluminum base (Al50Si50: 2.5g / cm 3 ) is much smaller than the density of the tungsten copper base and the density of the No. 10 steel frame. For the same size of tube shell base, the weight of the silicon aluminum base is about 1 / 4 to 1 / 7 of the weight of the tungsten copper base, and the overall tube shell weight is about 35% of the weight of the tungsten copper tube shell. In this type of product, the tube shell weight accounts for a high proportion (the tube shell weight usually accounts for more than 80% of the total weight of the product). After using the silicon aluminum tube shell base, the overall weight of the product can be reduced by about 50%, which can achieve a lightweight design of the product.

[0069] In addition, in the existing medium and high power IPM module design, the tungsten copper tube base and the No. 10 steel tube frame are welded with silver copper solder (melting point is about 700°C). The tube base 11 of this solution is preferably a silicon aluminum substrate made of Al50Si50 material. Since the melting point of the silicon aluminum substrate is lower than the welding temperature of the silver copper solder, the silver copper solder cannot be used for welding; in this regard, Figure 1 As shown, this solution uses gold-tin solder 16 (Au80Sn20) to weld the tube shell base 11 and the tube shell frame 12. Its melting point is 280°C, and the welding temperature is between 310°C and 330°C. The welding temperature of the gold-tin solder 16 is lower than the melting point of the silicon-aluminum base, and the gold-tin solder 16 can form a dense welding structure with an ultra-low void rate and high welding strength, and can form a reliable airtight packaging structure between the tube shell base 11 and the tube shell frame 12. In other words, this solution forms an airtight packaging structure by using gold-tin to weld the silicon-aluminum tube shell base 11 and the tube shell frame 12, which not only retains the high thermal conductivity of the product tube shell base 11, but also replaces the heavier WCu material, thereby realizing a lightweight design of the product.

[0070] In addition, it can be seen from the above that the tube shell base 11 and the tube shell frame 12 are welded by gold-tin solder 16. In order to ensure the welding quality, it is necessary to form an airtight packaging structure with high welding strength and high reliability here. The width of the gold-tin solder 16 is preferably equal to the thickness of the tube shell frame 12, and the thickness is preferably 50μm, which is used to ensure the filling amount of solder. Among them, during the melting process of the gold-tin solder 16, if part of the solder overflows onto the plane (upper surface) inside the tube shell base 11, it will affect the flatness of the inside of the tube shell base 11, and then affect the welding of the internal substrate and the tube shell. In this regard, in order to prevent the overflow of part of the solder from affecting the flatness of the inside of the tube shell base 11, accordingly, the upper surface of the tube shell base 11 has an internal assembly area for cooperating with the power board 13 and the signal board 14, such as Figure 1 As shown, a welding groove 25 for cooperating with the tube shell frame 12 is provided on the upper surface of the tube shell base 11. The welding groove 25 is located outside the internal assembly area to prevent the molten solder from overflowing into the internal assembly area of ​​the tube shell base 11, thereby ensuring the flatness of the internal assembly area (substrate welding area) of the tube shell base 11.

[0071] At the same time, the power board 13 is soldered to the tube shell base 11. The bottom layer of the tube shell base 11 is nickel-plated and the surface layer is gold-plated. The solder used in the product packaging process is generally low-temperature lead solder (63Sn37Pb) or lead-free solder (Sn96.5Ag3.0Cu0.5). This type of solder has excellent wettability on the gold-plated surface of the tube shell base 11, and it is easy to flow along the gold-plated surface of the tube shell base 11 to the welding groove 25, which will cause corrosion to the gold-tin solder 16, affecting the welding reliability between the tube shell base 11 and the tube shell frame 12. In this regard, if Figure 1 As shown, a welding isolation zone 30 is provided on the upper surface of the tube shell base 11 between the internal assembly area and the welding groove 25. In this solution, a precision laser etching process is used to remove the gold plating layer on the surface of the welding isolation zone 30 to form a welding barrier area. After the gold plating layer is removed, the nickel plating layer on the bottom surface is exposed. The wettability of solder on the gold plating layer is much better than that on the nickel plating layer. The molten solder will stay on the gold plating layer with good wettability and will not flow onto the nickel plating layer of the welding isolation zone 30, thereby effectively preventing the solder from flowing onto the welding groove 25 when the power board 13 is welded to the tube shell base 11.

[0072] It can be seen from the above technical solutions that the packaging structure of the high-performance IPM module provided by the embodiment of the present invention, on the one hand, retains the high thermal conductivity characteristics of the product shell base 11 after adopting the silicon aluminum tube shell base, and can reduce the overall weight of the product, thereby realizing the lightweight design of the product. On the other hand, since the material of the tube shell base is changed, the tube shell base and the tube shell frame are welded by matching gold-tin solder to ensure the feasibility of welding the tube shell base and the tube shell frame, and by providing a welding groove and a welding isolation belt on the tube shell base, it is convenient to prevent the molten solder from overflowing into the internal assembly area of ​​the tube shell base, thereby ensuring the flatness of the internal assembly area of ​​the tube shell base (substrate welding area), and effectively preventing the solder from flowing onto the welding groove when the power board is welded to the tube shell base.

[0073] In other words, this solution not only solves the problem of the heavy tube shell base, but also solves the related process problems caused by the change of the material of the tube shell base, such as using matching gold-tin solder to weld the tube shell base and the tube shell frame to ensure the feasibility of welding the tube shell base and the tube shell frame, and providing a welding groove and a welding isolation belt on the tube shell base to prevent the molten solder from overflowing into the internal assembly area of ​​the tube shell base, and to prevent the solder from flowing onto the welding groove when the power board is welded to the tube shell base.

[0074] In this scheme, if Figure 1 As shown, the welding groove 25 is lower than the internal assembly area, which is convenient for better blocking the molten solder from overflowing into the internal assembly area of ​​the tube shell base 11, thereby more effectively ensuring the flatness of the internal assembly area (substrate welding area) of the tube shell base 11; the width of the welding groove 25 is greater than the width of the tube shell frame 12, which is convenient for reserving a certain margin for the welding assembly of the tube shell frame 12.

[0075] Specifically, the soldering groove 25 is 0.2 mm to 0.5 mm lower than the internal assembly area. This height difference is greater than the maximum climbing height of the solder after melting, which can effectively prevent the molten solder from overflowing onto the internal assembly area of ​​the tube shell base 11, ensure the flatness of the substrate soldering area of ​​the tube shell base 11, and avoid affecting the welding of the internal substrate and the tube shell;

[0076] The width of the welding groove 25 is 0.2 mm to 0.3 mm greater than the width of the tube shell frame 12, so as to reserve sufficient margin for welding and assembly of the tube shell frame 12;

[0077] The width of the welding isolation zone 30 is 0.15 mm to 0.3 mm.

[0078] Furthermore, if Figure 1 As shown, the packaging structure of the high-performance IPM module provided by the embodiment of the present invention further includes a preformed copper strip 15;

[0079] Several pins 21 are connected to several corresponding pads of the power board 13 through the preformed copper tape 15. In other words, this solution realizes the electrical interconnection between the power board 13 and the pins 21 through the preformed copper tape 15, which can greatly improve the current capacity between the power board 13 and the pins 21, meet the high current overcurrent and miniaturization design requirements of the product, and the welding structure of the preformed copper tape 15 can release the welding adaptation stress and has higher connection reliability. Among them, the material of the preformed copper tape 15 is red copper, the thickness range is preferably between 0.1mm and 0.3mm, and the width range is preferably between 1.2mm and 2.5mm.

[0080] Furthermore, if Figure 4 As shown, the preformed copper strip 15 includes: a copper strip welding portion 18, a copper strip bending portion 19 and a plurality of copper strip welding holes 20;

[0081] The copper strip bending portion 19 is an inverted U-shaped bending structure, and the end of the first side portion (i.e., the first part) is higher than the end of the second side portion (i.e., the second part). The first side portion of the copper strip bending portion 19 is provided with a plurality of copper strip welding holes 20 for passing through a plurality of pins 21 one by one and welding with the plurality of pins 21 one by one.

[0082] The copper strip welding portion 18 is vertically connected to the end of the second side portion of the copper strip bending portion 19 and is used to be welded to a number of corresponding pads on the power board 13. Figure 5 As shown, the preformed copper strip 15 is provided with three bending parts so that it forms an inverted U-shaped copper strip with a turned edge, which is convenient for forming a U-shaped redundant bending structure of unequal height between the soldering points at both ends of the preformed copper strip 15. The existence of the U-shaped redundant bending structure can effectively release the welding adaptation stress generated during the welding process of the preformed copper strip 15, avoid soldering point failure, ensure the reliability of the welding of the preformed copper strip 15, and form a suspended structure with a certain span between the soldering point of the power board 1 and the soldering point of the pin 21 to ensure the stability of the welding of the preformed copper strip 15. In addition, the preformed copper strip 15 can also be flexibly designed according to the requirements of the connection between the soldering pad and the pin 21 of the power board 13, so that a preformed copper strip 15 that meets the connection requirements can be designed; wherein, the preformed copper strip 15 specifically includes four categories, and they are single substrate soldering pad and single pin connection copper strip (such as Figure 5 As shown), multiple substrate pads and single pin connection copper tape (as shown Figure 6 As shown), multiple substrate pads and multiple pin connection copper strips (as shown Figure 7 As shown), single substrate pads and multi-pin connection copper tape (as shown Figure 8 As shown), the flexibility and convenience of the internal substrate wiring of the product can be improved.

[0083] In the present solution, the welding between the power board 13 and the tube shell base 11, the power board 13 and the device, and the copper tape welding part 18 of the preformed copper tape 15 and the power board 13 are all completed at one time by the reflow soldering process. The solder has a certain fluidity in the molten state. At this time, the other end of the preformed copper tape 15 (the other end connected to the tube pin 21) has no solder and is in a free state. When the solder flows, the axial position of the copper tape welding hole 20 and the tube pin 21 will move. If the copper tape welding hole 20 moves toward the side wall of the tube shell and deviates from the design tolerance, that is, it is too close to the side wall of the tube shell, it will be detrimental to the subsequent welding operation and the mounting operation of the insulating film 23. In this regard, in order to avoid the axial position movement of the copper tape welding hole 20 and the tube pin 21 in this case; accordingly, if Figure 3 As shown, the inner end surface of the pin 21 is provided with a pin welding column 28, and the diameter of the copper strip welding hole 20 of the copper strip bending portion 19 is larger than the diameter of the pin welding column 28, and smaller than the diameter of the pin 21; wherein, the diameter of the copper strip welding hole 20 is 0.2mm to 0.4mm larger than the diameter of the pin welding column 28, and the diameter of the pin 21 is at least 0.4mm larger than the diameter of the pin welding column 28;

[0084] The copper strip welding hole 20 is used to pass through the pin welding column 28 of the pin 21, and the copper strip welding hole 20 contacts and welds with the pin welding column 28. In this way, not only can the pin welding column 28 be well penetrated by tin in the subsequent welding process, but the copper strip welding hole 20 can also be limited to avoid the position of the preformed copper strip 15 from shifting during the reflow soldering process and preventing the design tolerance from being exceeded. In addition, the pin welding column 28 of the pin 21 and the copper strip welding hole 20 are a perforated welding connection structure, which can ensure that even if the solder joint at this location undergoes secondary melting, the preformed copper strip 15 and the pin 21 will not pop off and desolder to cause an electrical open circuit.

[0085] Specifically, Figure 1 As shown, the outer end of the insulator 29 protrudes from the outer side wall of the tube shell frame 12 along the tube pin 21, and the inner end is flush with the inner side wall of the tube shell frame 12;

[0086] The packaging structure of the high-performance IPM module further includes: an insulating film 23 and a high-voltage silicone gel 24;

[0087] like Figure 1 As shown, the insulating film 23 is used to be bonded to the inner side wall of the tube shell frame 12, and is provided with an insulating film through hole 26 for passing the pin 21. The structure thereof can be referred to Fig. 9 As shown;

[0088] like Figure 3 As shown, the high withstand voltage silicone gel 24 is used to coat at least the edge of the insulating film 23 and between the hole edge of the insulating film through hole 26 and the pin 21 .

[0089] It should be noted that, as can be seen from the above, Figure 1 As shown, the tube shell frame 12 is welded on the tube shell base 11, the power board 13 is welded on the tube shell base 11, the signal board 14 is fixed on the tube shell base 11, and the cover plate 22 is encapsulated on the tube shell frame 12. The two opposite side walls of the tube shell frame 12 are provided with a plurality of insulators 29, and a plurality of pins 21 on each side are led out of the tube shell from the corresponding insulator 29; wherein the outer end of each insulator 29 extends outwardly along the axial direction of the pin 21 and protrudes from the outer side wall of the tube shell frame 12, that is, each insulator 29 adopts an outward convex structure, and when the lifting While the pressure-resistant insulation capacity between the pin 21 (external lead-out part) and the shell is improved, the diameter of the insulator does not change. The inner end of each insulator 29 is flush with the inner wall of the shell frame 12. In this way, each insulator 29 does not adopt an inward convex structure, and there is no need to extend the length of the inner lead-out part of the pin 21, thereby reducing the internal assembly space occupied. Moreover, without taking other pressure-resistant isolation measures and without increasing the diameter of the insulator, the pressure-resistant distance between the shell and the pin 21 at this point is insufficient, making it difficult to meet the pressure-resistant requirements of the product.

[0090] To this end, the present solution has an insulating film 23 glued to the inner wall of the tube shell frame 12 for leading out the pin 21, and the insulating film 23 is provided with an insulating film through hole 26 for passing the pin 21, and a high-voltage silicone gel 24 is coated on the edge of the insulating film 23 and between the edge of the hole of the insulating film through hole 26 and the pin 21 to improve the voltage insulation ability between the pin 21 (the inner lead-out part) and the shell; of course, in order to avoid the insulating film 23 from having problems such as decreased adhesion and peeling at some positions during the cleaning process (the cleaning liquid is an organic solvent), it is necessary to mount the insulating film 23 after all the solder joints inside the product are welded and cleaned. In addition, the insulator 29 uses a ceramic insulator to facilitate the formation of an external convex structure.

[0091] That is to say, this solution adopts different voltage-resistant insulation structures on the inside and outside of the tube shell; among them, an insulator protruding structure is adopted on the outside of the tube shell, and an adhesive insulating film 23 and an isolation structure coated with high-voltage silicone gel are adopted on the inside. In this way, without increasing the diameter of the insulator, the pin 21 can meet the high voltage-resistant requirements on both the inside and outside of the tube shell, that is, the high voltage-resistant requirements can be met between the pin 21 and the tube shell, which can not only meet the high voltage-resistant requirements of the high-performance IPM module, but also realize the miniaturized design of the high-performance IPM module.

[0092] In addition, it should be noted that the IPM module of this solution is an all-metal hermetic packaging structure. After the product is sealed, the interior is a normal pressure environment of inert gas. The insulating film 23 used inside and the silicone gel coated on the edge and through-hole of the insulating film 23 will not have problems such as mechanical wear and harmful corrosion under the double protection of the metal shell and the inert gas. If the pressure-resistant insulation structure inside the product is used on the outside of the tube shell, the product may be mechanically damaged during environmental testing and subsequent long-term application, causing damage to the insulating film 23, or environmental corrosion causing insulation failure. Therefore, the pressure-resistant insulation structure used on the inner wall of the tube shell cannot be applied to the outside of the tube shell.

[0093] That is to say, the packaging structure of the high-performance IPM module provided in the embodiment of the present invention adopts different voltage-resistant insulation structures on the inside and outside of the tube shell; wherein, an insulator protruding structure is adopted on the outside of the tube shell, and an isolation structure of an adhesive insulating film and a high-voltage-resistant silicone gel coating is adopted on the inside. In this way, without increasing the diameter of the insulator, the high voltage-resistant requirement can be met between the tube pin and the tube shell, which can not only meet the high voltage-resistant requirement of the high-performance IPM module, but also realize the miniaturized design of the high-performance IPM module.

[0094] In this embodiment, the number of insulating films 23 is two;

[0095] like Figure 1 As shown, the two insulating films 23 are respectively bonded to the two opposite inner side walls of the tube shell frame 12, and each of them is provided with a plurality of insulating film through holes 26 (such as Figure 2 shown);

[0096] like Figure 2 As shown, the high withstand voltage silicone gel 24 is used to coat at least the edges of the two insulating films 23 and between the edge of each insulating film through hole 26 and the corresponding pin 21. In this way, the high withstand voltage requirement can be met between the multiple pins 21 on each side and the inner side of the shell.

[0097] Specifically, as can be seen from the above, the present solution is to mount the insulating film 23 after all solder joints inside the product are soldered and cleaned. That is to say, after the pins 21 are connected to the pads of the power board 13 to form a closed path, the insulating film 23 is mounted. In this regard, in order to facilitate the bonding of the insulating film 23 by allowing multiple pins 21 on the same side to pass through multiple insulating film through holes 26 of the insulating film 23; accordingly, as Fig. 9As shown, each insulating film 23 is provided with a plurality of insulating film slits 27 distributed in parallel, and one side of the plurality of insulating film slits 27 is connected one by one with the plurality of through holes of the insulating film 23, and the other side is connected with the upper edge or the lower edge of the insulating film 23; preferably, in order to facilitate better loading of the insulating film 23, the other side of the plurality of insulating film slits 27 is connected with the lower edge of the insulating film 23; wherein, in the process of loading the insulating film 23, the lower side of the plurality of insulating film slits 27 of the insulating film 23 is first aligned one by one with the plurality of pins 21 on the same side, and then the insulating film 23 is lowered so as to pass through the plurality of pins 21, until the plurality of pins 21 pass through the plurality of insulating film through holes 26 one by one;

[0098] like Figure 2 As shown, the high-voltage silicone gel 24 is also used to coat the gap of each insulating film slit 27 of each insulating film 23, so that the gap of each insulating film slit 27 of each insulating film 23 is filled, which not only effectively closes the insulation path between the pin 21 and the tube shell, but also prevents the insulating film slit 27 from peeling or warping, and also has a reinforcing effect on the insulating film 23. In addition, the high-performance IPM module in this solution has high-voltage isolation requirements not only between the tube shell and the pin 21, but also between the high-voltage assembly area and the low-voltage assembly area on the substrate, and between the high-voltage area and the side wall of the tube shell, and these parts must be coated with high-voltage silicone gel 24.

[0099] In other words, the packaging structure of the high-performance IPM module provided by this solution can not only meet the design requirements of high current, high thermal conductivity, and high voltage resistance of the IPM module, but also realize the lightweight and miniaturized design of the product.

[0100] The embodiment of the present invention further provides a method for manufacturing a packaging structure of a high-performance IPM module, which is used to manufacture the packaging structure of the high-performance IPM module as described above, wherein the outer end of the insulator 29 of the packaging structure of the high-performance IPM module protrudes from the outer side wall of the tube shell frame 12 along the pin 21, and the inner end is flush with the inner side wall of the tube shell frame 12;

[0101] The packaging structure of the high-performance IPM module further includes: an insulating film 23 and a high-voltage silicone gel 24;

[0102] The insulating film 23 is used to be bonded to the inner side wall of the tube shell frame 12, and is provided with an insulating film through hole 26 for passing the pin 21;

[0103] The high withstand voltage silicone gel 24 is used to coat at least the edge of the insulating film 23 and between the edge of the insulating film through hole 26 and the pin 21;

[0104] refer to Fig.10 As shown, the manufacturing method comprises:

[0105] S1. Provide the tube shell base, tube shell frame, cover, power board, signal board, insulator, pin, preformed copper tape, insulation film and high-voltage silicone gel;

[0106] S2, welding the tube shell base and the tube shell frame; wherein the tube shell base and the tube shell frame are welded airtightly by using gold-tin solder;

[0107] S3, mounting: mounting the power board on the tube shell base, mounting the power board components on the surface of the power board, inserting the copper tape welding holes of the preformed copper tape into the pin welding columns of the corresponding pins, and mounting the copper tape welding part on the corresponding pads of the power board;

[0108] S4, reflow soldering: solder the power board to the base of the tube shell, solder the power board components to the surface of the power board, and solder the copper strip soldering part to the corresponding soldering pad of the power board;

[0109] S5, completing the welding of the copper tape welding holes of the preformed copper tape and the pin welding columns of the corresponding pins;

[0110] S6, complete welding cleaning;

[0111] S7, attaching the insulating film to the inner side wall of the tube shell frame; wherein the two insulating films are attached to two opposite inner side walls of the tube shell frame respectively;

[0112] S8, complete the assembly of the signal board, and fix the signal board assembly on the tube shell base;

[0113] S9, bonding the signal board and the power board;

[0114] S10, applying high-voltage silicone gel to the edge of the insulating film, between the edge of the through hole of the insulating film and the pin, and between the high-voltage assembly area and the low-voltage assembly area of ​​the power board; wherein the high-voltage silicone gel is also applied to the gap of each slit coated on each insulating film, and between the high-voltage area of ​​the power board and the side wall of the tube shell;

[0115] S11. Install the cover to complete the packaging.

[0116] It should be noted that, since this solution is used to manufacture the packaging structure of the above-mentioned high-performance IPM module, it also has corresponding beneficial effects. For details, please refer to the previous description, which will not be repeated here.

[0117] The present invention is further described below in conjunction with specific embodiments:

[0118] See also Figures 1 to 3 A packaging structure of a high-performance IPM module includes: a tube shell base 11, a tube shell frame 12, a cover plate 22, a power board 13, a signal board 14, a preformed copper tape 15, a preformed insulating film (i.e., an insulating film 23), and a high-voltage silicone gel 24.

[0119] The tube shell base 11 and the tube shell frame 12 are welded with gold-tin solder 16 to form an airtight packaging structure.

[0120] In order to meet the wide range of operating temperature requirements (-55℃~125℃), the internal substrate of the traditional IPM motor drive module needs to select materials with high temperature resistance. At the same time, since this type of product is a high-voltage power product, it needs to have good insulation and thermal conductivity. The operating temperature of the ceramic substrate can reach above 300℃, and it has good thermal conductivity and insulation performance. The thermal conductivity is between 85W / (mK) and 200W / (mK), and the withstand voltage insulation strength is ≥20KV / mm, which can meet the needs of this type of product. Therefore, the circuit of the internal power part of this type of product usually uses a ceramic substrate as a carrier. A large number of power devices are distributed on the power board 13. In order to meet the high thermal conductivity requirements of the product, a large-area welding process is used between the bottom of the ceramic substrate and the tube shell base 11. In order to meet the rapid temperature change requirements of the product within a wide temperature range, the thermal expansion coefficient of the tube shell base 11 needs to match the thermal expansion coefficient of the ceramic substrate to avoid cracking of the substrate due to mismatch of thermal expansion coefficients during welding, environmental testing, and product application.

[0121] For IPM modules with a wide temperature range, a fully metal airtight packaged shell is required. The shell is usually a No. 10 steel integrated shell, but because its shell thermal conductivity is relatively low (about 55W / (mK)), it is generally used in low-power products. For medium and high-power IPM modules, in order to meet the high thermal conductivity requirements, the prior art usually uses a tungsten-copper (or molybdenum-copper) shell base and a No. 10 steel shell frame 12 to form an airtight package shell. The tungsten-copper base and the No. 10 steel frame are welded at high temperature with silver-copper solder, and then plated. The tungsten-copper base has a very high thermal conductivity, which can meet the high thermal conductivity requirements of medium and high-power IPM modules. At the same time, the thermal expansion coefficient of the tungsten-copper base is close to that of No. 10 steel, which can meet the high reliability requirements of the product. However, the density of tungsten copper is too large. For example, the density of tungsten copper made of the commonly used W50Cu50 material is about 12.2g / cm 3 The density of tungsten copper of W85Cu15 material is about 16.4g / cm 3 , much greater than the density of No. 10 steel (7.9g / cm 3 ), and in this type of product, the weight of the shell is relatively high (the weight of the shell usually accounts for more than 80% of the total weight of the product). Therefore, although the shell made of tungsten copper meets the high thermal conductivity requirements of medium and large power IPM modules, its density is too high, which is not conducive to the lightweight design of the product.

[0122] In order to meet the high thermal conductivity and light weight requirements of the product, in this solution, the tube shell base 11 uses a silicon aluminum substrate made of Al50Si50 material. The silicon aluminum material has high strength and can be used as a tube shell substrate. Its thermal conductivity is 140W / (mK), which can meet the high thermal conductivity requirements of medium and high power IPM modules. The thermal expansion coefficient of silicon aluminum material is 11.5×10 -6 / K, when used as a shell base, the thermal expansion coefficient of the 10# steel shell frame (13.0×10 -6 / K) matches to meet the high reliability requirements of the product. The density of the silicon aluminum base (Al50Si50: 2.5g / cm 3 ) is much smaller than the density of the tungsten copper base and the density of the No. 10 steel base. For the same size of tube shell base, the weight of the silicon aluminum base is about 1 / 4 to 1 / 7 of the weight of the tungsten copper base, and the overall tube shell weight is about 35% of the weight of the tungsten copper tube shell. In this type of product, the weight of the tube shell accounts for a high proportion (the weight of the tube shell usually accounts for more than 80% of the total weight of the product). After using the silicon aluminum tube shell, the overall weight of the product can be reduced by about 50%, which can achieve a lightweight design of the product.

[0123] In the design of medium and large power IPM modules in the prior art, silver-copper solder (melting point of about 700°C) is used for welding between the tungsten copper shell base and the No. 10 steel shell base. The shell base of this solution is preferably a silicon-aluminum substrate made of Al50Si50 material. Since the melting point of the silicon-aluminum substrate is lower than the welding temperature of the silver-copper solder, silver-copper solder cannot be used for welding; therefore, this solution uses gold-tin solder 16 (Au80Sn20) to weld the shell base 11 and the shell frame 12. Its melting point is 280°C and the welding temperature is between 310°C and 330°C. The gold-tin welding temperature is lower than the melting point of the silicon-aluminum base, and the gold-tin solder 16 can form a dense welding structure with an ultra-low void rate and high welding strength, and can form a reliable airtight packaging structure between the shell base 11 and the shell frame 12.

[0124] A welding groove (welding platform) 25 is designed on the tube shell base 11 , and a welding isolation zone 30 is designed between the internal assembly area of ​​the tube shell base 11 and the welding groove 25 .

[0125] The shell base 11 and the shell frame 12 are welded by gold-tin solder 16. To ensure the welding quality, an airtight packaging structure with high welding strength and high reliability is formed here. The width of the metal solder is preferably equal to the thickness of the shell frame 12, and the solder thickness is preferably 50 μm, which is used to ensure the filling amount of the solder. During the melting process of the solder, part of the solder will overflow to the area outside the shell frame 12. If the solder overflows into the plane inside the shell, it will affect the flatness of the inside of the shell, and then affect the welding of the internal substrate and the shell. In this solution, a welding groove 25 is designed on the shell base 11. Preferably, the width of the welding groove 25 is 0.2 mm to 0.3 mm larger than the width of the shell frame 12, and a certain margin is reserved for the welding assembly of the shell frame 12. In order to ensure that the distance between the shell frame 12 and the internal assembly area of ​​the shell base is as large as possible, the welding groove 25 is flush with the outside of the shell frame. The height of the welding groove 25 is 0.2mm-0.5mm lower than the internal assembly area of ​​the tube shell base 11. The height difference is greater than the maximum climbing height of the solder after melting, which can effectively prevent the molten solder from overflowing into the tube shell base 11 and ensure the flatness of the substrate welding area of ​​the tube shell base 11.

[0126] The power board 13 is soldered to the tube shell base 11. The bottom layer of the tube shell base 11 is nickel-plated and the surface layer is gold-plated. The solder used in the product packaging process is generally low-temperature lead solder (63Sn37Pb) or lead-free solder (Sn96.5Ag3.0Cu0.5). This type of solder has excellent wettability on the tube shell base 11 with gold-plated surface. It is easy to flow along the gold-plated surface of the tube shell base 11 to the welding groove 25, and then cause corrosion to the gold-tin solder 16, affecting the welding reliability between the tube shell base 11 and the tube shell frame 12. For this reason, the present solution is designed with a welding isolation zone 30 between the internal assembly area of ​​the tube shell base 11 and the welding groove 25. Figure 1 As shown, the width of the welding isolation zone 30 is 0.15mm~0.3mm, and the gold plating on the surface of the welding isolation zone 30 is removed by a precision laser etching process to form a welding barrier area. After the gold plating is removed, the nickel plating on the bottom is exposed. The wettability of solder on the gold plating is much better than that on the nickel plating. The molten solder will stay on the well-wetted gold plating and will not flow onto the nickel plating of the welding isolation zone 30. Therefore, it can effectively prevent the solder from flowing onto the welding groove 25 when the power board 13 is welded to the tube shell base 11.

[0127] The power board 13 is welded on the tube shell base 11 , and the signal board 14 is fixed on the tube shell base 11 .

[0128] The power board 13 is welded with high-power devices, which generate a lot of heat. In order to meet the high thermal conductivity requirements of the product, a good heat transfer path must be formed between the high-power devices and the outer surface of the tube shell base 11. Therefore, in this solution, a large-area welding process is used between the power board 13 and the tube shell base 11, which can meet the high thermal conductivity requirements of the product and the high welding strength requirements of the substrate.

[0129] In this solution, the signal board 14 is equipped with components of the control circuit part, which do not involve large current and heat generation requirements. Therefore, the signal board 14 can be fixed to the tube shell base 11 by welding or bonding technology.

[0130] The preformed copper strip 15 includes a copper strip welding portion 18, a copper strip bending portion 19, and a copper strip welding hole 20; the copper strip welding portion 18 is welded to the power board 13; and the welding hole of the preformed copper strip 15 is welded to the pin welding area (ie, the pin welding column 28).

[0131] In this solution, a preformed copper strip 15 is used to connect the power board 13 and the lead wire of the tube shell. Preferably, the copper strip is made of red copper, which has a strong current carrying capacity of about 139A / mm. 2 .

[0132] Based on the requirements of flow capacity, support strength and stress release, the thickness of the preformed copper strip 15 in this solution is preferably in the range of 0.1 mm to 0.3 mm, and the width is preferably in the range of 1.2 mm to 2.5 mm.

[0133] In the design of miniaturized products, it is necessary to complete the welding connection between the substrate (including the power board and the signal board) and the pin 21 in a small space. Since the welding connection distance is short and both ends are welded fixed structures, when the connecting lead is thick, a large welding adaptation stress will be generated. In the subsequent environmental test or product application process, cracks may be formed at the joints of the solder joints at both ends, affecting the reliability of the product. This solution designs three bends in the copper strip structure. Through the setting of the three bends, an inverted U-shaped redundant bend structure is formed between the solder joints at both ends of the preformed copper strip 15. The existence of the inverted U-shaped redundant bend structure can effectively release the welding adaptation stress generated during the welding process, avoid solder joint failure, and ensure the reliability of the product.

[0134] When the thickness of the preformed copper strip 15 is too thin, it cannot meet the high current overcurrent requirements of the product. At the same time, after the copper strip is assembled and welded, a suspended structure with a certain span will be formed between the substrate solder joint and the pin 21 solder joint. If the copper strip is too thin, it cannot produce sufficient supporting strength. After high-stress mechanical environment tests such as impact and constant acceleration, the copper strip may deform and collapse, resulting in reliability defects. When the thickness of the preformed copper strip 15 is relatively thick, at a shorter welding distance, the overall rigidity of the preformed copper strip 15 is large, and the adaptation stress generated during the welding process cannot be effectively released. After experimental verification, the thickness range of the preformed copper strip 15 in this scheme is preferably between 0.1mm and 0.3mm, and the width range is preferably between 1.2mm and 2.5mm.

[0135] The preformed copper strip 15 welding structure of this scheme can meet the miniaturization design requirements of the product. Compared with the coarse aluminum wire bonding connection structure of the prior art, the copper current carrying capacity of the copper strip welding structure of this scheme is higher than the aluminum material of the coarse aluminum wire. At the same time, due to the limitation of the aluminum wire diameter (the diameter of the commonly used coarse aluminum wire is between 100μm and 380μm), the cross-sectional area of ​​a single aluminum wire is much smaller than the copper strip of this scheme. In the specific embodiment of this scheme, taking 380μm aluminum wire as an example, the cross-sectional area of ​​a single aluminum wire is 0.113mm 2 , and the copper strip in this scheme is calculated according to the thickness of 0.2mm and the width of 2mm, and the cross-sectional area of ​​the copper strip is 0.4mm 2 Calculation shows that the cross-sectional area of ​​the copper strip in the above design is 3.54 times that of the 380μm thick aluminum wire, and its current carrying capacity is equivalent to that of 5 380μm thick aluminum wires (the current carrying capacity of a single wire is about 27.64A / mm 2 ). The welding hole of the preformed copper tape 15 of this solution is connected to the welding area of ​​the pin 21. Taking the pin 21 with a diameter of 1mm as an example, usually only two 380μm aluminum wires can be bonded and connected on the pin with a diameter of 1mm. It can be seen that in this embodiment, the preformed copper tape 15 welding structure of this solution can greatly improve the current flow capacity between the power board 13 and the pin 21. Compared with the traditional aluminum wire bonding connection structure, its current flow capacity is improved by 2.5 times, which can meet the high current flow and miniaturization design requirements of the product.

[0136] Similarly, compared with the thick lead welding structure of the prior art, the preformed copper strip 15 welding structure of the present solution can greatly improve the current capacity between the power board 13 and the pin 21, meet the large current overcurrent and miniaturization design requirements of the product, and the copper strip welding structure can release the welding adaptation stress and has higher connection reliability. In the thick lead welding structure of the prior art, in order to meet the large current flow requirements, it is necessary to use a thicker enameled copper wire. This structure has two problems: one is that the lead is harder, not easy to form, and has high stress, making it difficult to achieve high-density connection in a small space; the second is to meet the reliability requirements and prevent the heat from being transferred to the inside of the product when welding the external pins during the product application process, causing the internal solder joints to melt, resulting in the enameled wire and the pin being separated. The enameled wire needs to be soldered around the shell pin 21, and the thicker lead is not easy to form a soldering ring, which affects the product reliability. If the problem of large structural stress is to be solved, it is necessary to lengthen the lead length and design a larger soldering ring, which is also not conducive to the miniaturization design of the product.

[0137] In addition, the preformed copper strip 15 can be flexibly designed according to the requirements of connecting the substrate pad and the tube shell pin 21 inside the product, and the preformed copper strip 15 that meets the connection requirements is designed, which specifically includes 4 categories: (such as Figure 5 As shown) single substrate pad and single pin connection copper tape, (as shown Figure 6 As shown) multiple substrate pads and single pin connection copper tape, (as shown Figure 7 As shown) multiple substrate pads and multiple pins connected to the copper tape, (as shown Figure 8 The single substrate pad and multi-pin connection copper tape can improve the flexibility and convenience of the internal substrate wiring of the product.

[0138] The preformed copper strip 15 is designed with a copper strip welding portion 18, and a copper strip welding area (soldering pad) is designed on the power board 13. The copper strip welding area is larger than each side of the copper strip welding portion 18 by more than 0.1 mm, and sufficient tin creeping area is reserved. The copper strip welding portion 18 and the copper strip welding area are welded with low-temperature lead solder (63Sn37Pb) or lead-free solder (Sn96.5Ag3.0Cu0.5). The welding strength is high, which can meet the product's current flow requirements and also meet the high reliability requirements in terms of mechanical strength.

[0139] The medium and high power IPM modules are generally electrically interconnected with the external PCB substrate by welding connection during product application. The selected solder is generally low temperature lead solder (63Sn37Pb). Because the output current of the product is large and the tube shell pin 21 is thick, a welding method with large heat capacity (such as high power soldering iron, wave soldering, etc.) is required for welding, which may easily cause the risk of secondary melting of the internal solder joints corresponding to the pins 21. In this solution, the preformed copper strip 15 is designed with a copper strip welding hole 20, and the pin welding area and the copper strip welding hole 20 are a perforated welding connection structure, which can ensure that even if the solder joint at this location undergoes secondary melting, the copper strip and the pin will not pop off and desolder to cause an electrical open circuit.

[0140] The tube shell frame 12 is provided with a ceramic insulator, a tube pin 21 and a tube pin welding area at the front end of the pin; the ceramic insulator is flush with the inner side of the tube shell frame 12 and protrudes outward.

[0141] In order to meet the working requirements of the product in a wide temperature range (-55℃~125℃), the IPM module usually adopts a full metal airtight package tube shell. The tube shell and the pin 21 are both made of metal. The metal pin 21 (made of copper or copper core composite material) is insulated and isolated from the shell (made of No. 10 steel) by an insulator. In the IPM module of the prior art, in order to meet the high withstand voltage insulation requirements of the product (generally between 650V~2500V), large diameter insulators are usually selected. In the specific implementation of this scheme, it is designed with 1500V DC insulation withstand voltage. According to the design standard of 1000V DC / mm, when the diameter of the pin 21 is 1mm, in order to ensure the insulation withstand voltage requirement of 1500V DC, an insulator with a diameter of 4.0mm is required to be designed to insulate between the pin 21 and the shell. Large diameter insulators will increase the height of the product shell and increase the spacing between the pins 21, making it impossible to achieve miniaturization design while being compatible with high withstand voltage insulation.

[0142] In this solution, in order to make the product meet the design requirements of high withstand voltage insulation and miniaturization at the same time, preferably, the ceramic insulator is flush with the inner side of the tube shell frame 12 and protrudes on the outer side. Compared with the insulators in the prior art, the insulator in this solution is designed with a protrusion on the outer side of the tube shell frame 12 (the protrusion length can be designed according to the requirements of the withstand voltage value) to improve the withstand voltage insulation ability between the pin 21 and the shell. In the specific implementation of this solution, the design is based on 1500V DC insulation withstand voltage, and the protrusion length of the protrusion is designed according to the design standard of 1000V DC / mm. The protrusion length is greater than 1.5mm, which can meet the isolation withstand voltage requirement of 1500V DC between the pin 21 and the shell. Since the protrusion of the insulator extends outward along the axial direction of the pin 21, while improving the insulation withstand voltage strength between the pin 21 and the shell, it does not cause the insulator diameter to change, so it will not increase the height of the shell shell and the spacing between the pins 21, so that the product meets the requirements of high withstand voltage and miniaturization design at the same time.

[0143] It should be noted that the medium and large power IPM modules discussed in this solution, in order to meet the requirements of high thermal conductivity during application, have the following assembly structure: the heat dissipation surface at the bottom of the product is directly fixed to the user's heat dissipation plate or metal shell, and the pin 21 is fixed to the user's PCB board by welding. Under this assembly structure, there will be a large stress on the pin 21 after welding. Therefore, if Figure 1 As shown, when designing the structure of this type of product, a certain stress release area is reserved between the bending point of the pin 21 and the tube shell. The length of the stress release area is related to the diameter of the pin 21, and is generally between 3.5mm and 5mm. In this solution, the protruding length of the insulator is generally between 1mm and 2.5mm (which can meet the withstand voltage insulation requirements between 1000V and 2500V). The insulator is axially concentric with the pin 21, and the protruding length is less than the length of the stress release area of ​​the pin 21. While meeting the high withstand voltage requirements of the product, no additional external space is occupied.

[0144] The copper strip welding portion 18 is welded to the power board 13 ; the welding hole of the preformed copper strip 15 is welded to the pin welding area.

[0145] The welding between the power board 13 and the tube shell, the power board 13 and the device, and the welding part of the preformed copper strip 15 and the power board 13 are all completed at one time by using the reflow soldering process. The solder has a certain fluidity in the molten state. At this time, there is no solder at the other end of the copper strip (the welding area with the pin) and it is in a free state. When the solder flows, the axial position of the copper strip welding hole 20 and the pin 21 will move. If the copper strip welding hole 20 moves toward the side wall of the tube shell and deviates from the design tolerance, it is too close to the side wall of the tube shell, which is not conducive to the welding operation and the mounting operation of the insulating film 23 in the subsequent process. In this solution, a pin welding area (pin welding column) is designed at the front end of the pin 21, and the diameter of the pin 21 is at least 0.4 mm larger than the pin welding area, while the welding hole diameter of the preformed copper strip 15 is larger than the diameter of the pin welding area and smaller than the diameter of the pin 21, which can ensure good tin penetration of the pin welding area during the subsequent welding process, and limit the copper strip welding hole 20 to prevent the copper strip from shifting in position during the reflow soldering process and exceeding the design tolerance.

[0146] The preformed insulating film is attached to the inner wall of the tube shell frame 12, and is designed with through holes matching the tube pins 21 and slits for the tube pins 21 to pass through during installation.

[0147] The withstand voltage insulation structure design between the tube shell and the pin 21 adopts an insulator convex structure on the outer side of the tube shell. As discussed above, since the external lead-out portion of the pin 21 is designed with a stress release area, the convex structure does not occupy additional space. On the inner wall of the tube shell, the lead-out length of the pin 21 is generally about 2.5mm to meet the welding requirements. If the same insulator convex structure is used inside, the length of the lead-out portion of the pin 21 needs to be extended (1mm to 2.5mm), which will occupy the internal assembly space and affect the product assembly density.

[0148] In this solution, in order to make the product meet the design requirements of high withstand voltage insulation and miniaturization at the same time, preferably, the ceramic insulator is flush with the inside of the tube shell base 12. Because the insulator is flush with the inner wall of the tube shell, if no other withstand voltage isolation measures are taken and the diameter of the insulator is not increased, the withstand voltage distance between the tube shell and the pin 21 at this location is insufficient, and the withstand voltage requirement of the product is not met.

[0149] To this end, in the insulation structure of this solution, a preformed insulation film is designed on the inner wall of the tube shell, and a through hole matching the pin 21 is designed on the insulation film 23. The structure is as follows: Fig. 9As shown. In order to avoid problems such as decreased adhesion and peeling of some parts of the insulating film 23 during the cleaning process (the cleaning liquid is an organic solvent), the insulating film 23 needs to be mounted after all solder joints inside the product are welded and cleaned. However, at this time, the pin 21 and the preformed copper sheet have been welded, and a closed-loop path is formed between the power board 13, the preformed copper strip 15, the pin 21, and the tube shell. If the through hole on the insulating film 23 is also a closed-loop structure, it cannot be mounted on the inner wall of the tube shell. For this reason, a slit structure is designed on the insulating film 23 in the present embodiment, and the insulating film 23 passes through the closed-loop structure formed between the power board 13, the preformed copper strip 15, the pin 21, and the tube shell through the slit structure, and is mounted on the inner wall of the tube shell.

[0150] It should be noted that the IPM module in this solution is an all-metal airtight packaging structure. After the product is sealed, the interior is a normal pressure environment of inert gas. The preformed insulating film used inside and the silicone gel coated on the edge of the insulating film have double-layer protection of the metal shell and the inert gas, and will not have problems such as mechanical wear and harmful corrosion. If the pressure-resistant insulating structure inside the product is used on the outside of the tube shell, the product may be mechanically damaged during environmental testing and subsequent long-term application, causing damage to the insulating film 23, or environmental corrosion causing insulation failure. Therefore, the pressure-resistant insulating structure used on the inner wall of the tube shell cannot be applied to the outside of the tube shell.

[0151] In summary, in view of the structural characteristics of medium and large power IPM modules, this solution adopts different voltage-resistant insulation structures on the inside and outside of the tube shell: the outside adopts an insulator convex structure, and the inside adopts an insulating film 23 and a silicone gel isolation structure, which can not only meet the high voltage resistance requirements of the product, but also realize the miniaturization design of the product.

[0152] The high-voltage silicone gel 24 is coated on the high-voltage isolation area inside the product and the edge of the pre-formed insulating film.

[0153] The diameter of the through hole of the preformed insulating film is 0.1 mm to 0.2 mm larger than the diameter of the pin 21. Figure 2 and Figure 3 As shown, the diameter of the ceramic insulator is generally 1mm to 1.5mm larger than the diameter of the pin 21. After the insulating film 23 is mounted, the insulating film 23 and the ceramic insulator have an overlap area of ​​at least 0.4mm. However, due to the problem of the fit between the insulating film 23, the ceramic insulator and the tube shell, there will be a micro gap in the middle, resulting in a defective insulation path between the tube shell and the pin 21. At the same time, the insulating film 23 is designed with an insulating film slit 27. During mounting, there may be a micro gap at the slit interface, and it is easy to peel or warp.

[0154] In order to solve the above problems, in this solution, high-voltage silicone gel 24 is used to coat the area around the through hole and the cut. The silicone gel has excellent fluidity and can fill the micro gaps under the insulating film 23 and at the cut, ensuring that the insulating path between the pin 21 and the shell body is effectively closed, while also reinforcing the insulating film 23.

[0155] The insulating film 23 is preferably made of polyimide (dielectric strength is 100-300kV / mm), with a single layer thickness of 0.1mm to 0.2mm, and a breakdown voltage of the single layer > 10kV. The silicone gel is a high-voltage silicone gel (dielectric strength is 17kV / mm), with a typical coating thickness of ≥ 0.1mm, and the withstand voltage after coating can reach 1700V. Combined with the previous discussion, when a single-layer insulating film is used, the withstand voltage insulation capacity between the lead and the pin 21 on the inner side of the tube shell is ≥ 1700V, which meets the high withstand voltage requirements of the IPM module.

[0156] The IPM module in this solution has high-voltage insulation requirements not only between the tube shell and the pin 21, but also between the high-voltage assembly area and the low-voltage assembly area on the substrate, and between the high-voltage area and the side wall of the tube shell. If a design scheme that increases the insulation distance is adopted, the isolation area will occupy too much internal wiring space, which is not conducive to the miniaturization design of the product. Therefore, in this solution, high-voltage silicone gel 24 is used to coat the high-voltage isolation area inside the product, which can greatly improve the assembly density of the product while meeting the high-voltage insulation requirements.

[0157] The base material of the tube shell base 11 is silicon aluminum, and the composition is Al50Si50. The base material of the tube shell frame 12 is No. 10 steel. The surfaces of the tube shell base 11 and the tube shell frame 12 are nickel-plated and gold-plated.

[0158] As mentioned above, in order to meet the high thermal conductivity and lightweight requirements of the product. In this solution, the tube shell base 11 uses a silicon aluminum substrate made of Al50Si50 material. The silicon aluminum material has high strength and can be used as a tube shell substrate. Its thermal conductivity is 140W / (m·K), which can meet the high thermal conductivity requirements of medium and high power IPM modules. When used as a tube shell base, the silicon aluminum base matches the thermal expansion coefficient of the No. 10 steel tube shell frame 12 and the internal ceramic substrate to meet the high reliability requirements of the product. The density of the silicon aluminum base is much smaller than that of the tungsten copper base and the No. 10 steel base, which can achieve a lightweight design of the product.

[0159] As mentioned above, because the melting point of the silicon-aluminum substrate is lower than the welding temperature of the silver-copper solder, the silicon-aluminum shell base cannot be welded using the silver-copper solder in the prior art. Therefore, this solution uses gold-tin solder 16 (Au80Sn20) to weld the tube shell base 11 and the tube shell frame 12. Its melting point is 280°C, and the welding temperature is between 310°C and 330°C. The gold-tin welding temperature is lower than the melting point of the silicon-aluminum base, and the gold-tin solder 16 can form a dense welding structure with an ultra-low void rate and high welding strength, forming a reliable airtight packaging structure between the tube shell base 11 and the tube shell frame 12.

[0160] In order to meet the gold-tin welding requirements of the silicon aluminum tube shell base 11 and the No. 10 steel tube shell base 12, in the packaging structure of this solution, nickel and gold are plated on the surface of the tube shell base 11 and the tube shell frame 12. The outermost gold plating layer is used as a welding layer and the gold-tin solder 16 to complete the welding, and the nickel plating layer at the bottom of the gold plating layer is used as a welding barrier layer to prevent the gold-tin solder 16 from penetrating downward, reduce the welding reliability, and form a high-quality welding layer.

[0161] The welding groove 25 is 0.2 mm to 0.5 mm lower than the internal assembly area of ​​the tube shell base 11 , and the width of the welding groove 25 is 0.2 mm to 0.3 mm greater than the width of the tube shell frame 12 .

[0162] When the welding groove 25 of the tube shell base 11 is welded to the tube shell frame 12, part of the solder will overflow to the area outside the tube shell frame 12 during the melting process of the solder. If the solder overflows to the assembly area inside the tube shell base 11, it will affect the flatness of the tube shell base 11, and further affect the welding of the internal substrate and the tube shell. In this solution, preferably, the width of the welding groove 25 is 0.2mm to 0.3mm larger than the width of the tube shell frame 12, so as to reserve a certain margin for the welding assembly of the tube shell frame 12. The welding groove 25 is 0.2mm to 0.5mm lower than the internal assembly area of ​​the tube shell base 11. The height difference is greater than the maximum climbing height of the solder after melting, which can effectively prevent the molten solder from overflowing to the assembly area inside the tube shell base 11, thereby ensuring the flatness of the substrate welding area of ​​the tube shell base 11 and avoiding affecting the welding of the internal substrate and the tube shell.

[0163] The width of the welding isolation zone 30 is 0.15 mm to 0.3 mm.

[0164] As mentioned above, in order to prevent the solder (low-temperature leaded solder 63Sn37Pb or lead-free solder Sn96.5Ag3.0Cu0.5) from flowing along the gold-plated surface of the shell base 11 onto the welding groove 25 when the power board 13 is welded to the tube shell base 11, thereby causing corrosion to the welding material (gold-tin solder 16) between the tube shell base 11 and the tube shell frame 12, the present solution is designed with a welding isolation zone 30 between the assembly area inside the tube shell base 11 and the welding groove 25. Preferably, the width of the welding isolation zone 30 is 0.15 mm to 0.3 mm, and a precision laser etching process is used to remove the gold plating on the surface of the welding isolation zone 30 to form a welding barrier zone.

[0165] The preformed copper strip 15 is made of red copper with a thickness ranging from 0.1 mm to 0.3 mm. The diameter of the copper strip welding hole 20 is 0.2 mm to 0.4 mm larger than the diameter of the pin welding area. The diameter of the pin 21 is at least 0.4 mm larger than the pin welding area.

[0166] In this solution, there is a perforated welding structure between the copper strip and the pin 21. In order to achieve a good assembly between the copper strip welding hole 20 and the pin welding area, preferably, the diameter of the copper strip welding hole 20 is between 0.2mm and 0.4mm larger than the diameter of the pin welding area. At the same time, the diameter of the pin 21 is at least 0.4mm larger than the pin welding area, which can ensure that the diameter of the copper strip through hole is smaller than the diameter of the pin 21, avoiding the position shift of the copper strip during the reflow soldering process and exceeding the design tolerance.

[0167] The through hole diameter of the preformed insulating film is 0.1mm to 0.2mm larger than the diameter of the pin 21, and the cut connects the edge of the preformed insulating film and the through hole; the high-voltage silicone gel 24 is coated on the high-voltage isolation area inside the product and the edge of the preformed insulating film 23.

[0168] In the IPM module of this solution, there is a need for high-voltage isolation between the high-voltage assembly area and the low-voltage assembly area on the substrate, and between the high-voltage area and the side wall of the tube shell. If a design scheme of increasing the insulation distance is adopted, the isolation area will occupy too much internal wiring space, which is not conducive to the miniaturization design of the product. Therefore, in this solution, high-voltage silicone gel 24 is used to coat the high-voltage isolation area inside the product, which can greatly improve the assembly density of the product while meeting the voltage insulation requirements.

[0169] This solution also provides a manufacturing method for manufacturing any of the above-mentioned packaging structures. Fig.10 A schematic flow chart of a process method provided in an embodiment of the present invention, wherein the production method comprises:

[0170] Step S01: providing a tube shell base, a tube shell frame, a cover plate, a power board, a signal board, an unformed strip copper tape, a preformed insulating film, and a high-voltage silicone gel;

[0171] Step S02: forming the unformed strip copper strip into a preformed copper strip that meets the requirements;

[0172] Among them, the preformed copper strip can be formed using precision tooling or professional forming equipment;

[0173] Step S03: completing the welding of the tube shell base and the tube shell frame;

[0174] Step S04: Complete mounting: mount the power board onto the base of the tube shell; mount the components onto the surface of the power board; insert one end of the preformed copper tape welding hole into the corresponding pin welding area, and mount the copper tape welding part onto the corresponding pad of the power board;

[0175] Step S05: reflow soldering: completing the soldering of the power board and the tube shell base, the components on the surface of the power board and the power board, and the soldering part of the preformed copper strip and the power board;

[0176] Step S06: completing the welding of the copper strip and the pin welding area;

[0177] Step S07: completing welding cleaning;

[0178] Step S08: completing the mounting of the preformed insulating film and the inner wall of the tube shell frame;

[0179] Step S09: completing the assembly and fixing of the signal board;

[0180] Step S10: completing the bonding connection between the signal board and the power board;

[0181] Step S11: completing high-voltage silicone gel coating.

[0182] The silicone gel coating area includes: around the through hole, at the slit, between the high-voltage assembly area and the low-voltage assembly area on the substrate, and between the high-voltage area and the side wall of the tube shell.

[0183] Step S12: parallel seam welding to complete the sealing of the product.

[0184] In summary, this solution forms an airtight packaging structure by using gold-tin to weld the silicon-aluminum base and the tube shell frame, which not only retains the high thermal conductivity of the product tube shell base, but also replaces the heavier WCu material to achieve a lightweight design of the product. By using preformed copper tape, the high current demand of the product is met, and the miniaturization design demand of the product is realized. At the same time, by designing an outward convex ceramic insulator on the outside of the product, pasting a preformed insulating film inside the product, and partially coating it with high-voltage silicone gel, the high-voltage design demand of the miniaturized product is realized. In other words, the packaging structure and manufacturing method of a high-performance, high-reliability IPM motor drive module disclosed in this solution can not only meet the design requirements of large current, high thermal conductivity, and high voltage resistance, but also realize the lightweight and miniaturization design of the product.

[0185] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0186] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A packaging structure of a high-performance IPM module, comprising: The tube shell base (11), the tube shell frame (12), the cover plate (22), the power board (13), the signal board (14), the insulator (29) and the tube pin (21), are characterized in that: The material of the tube shell base (11) is silicon aluminum; The tube shell base (11) and the tube shell frame (12) are welded by means of gold-tin solder (16); The power board (13) is welded to the tube shell base (11); The signal board (14) is fixed on the tube shell base (11); The upper surface of the tube shell base (11) has an internal assembly area for cooperating with the power board (13) and the signal board (14); the upper surface of the tube shell base (11) is provided with a welding groove (25) for cooperating with the tube shell frame (12); and the upper surface of the tube shell base (11) is provided with a welding isolation zone (30) located between the internal assembly area and the welding groove (25).

2. The packaging structure of the high-performance IPM module according to claim 1, characterized in that: The welding groove (25) is lower than the internal assembly area, and the width of the welding groove (25) is greater than the width of the tube shell frame (12).

3. The packaging structure of the high-performance IPM module according to claim 2, characterized in that: The welding groove (25) is 0.2 mm to 0.5 mm lower than the internal assembly area, and the width of the welding groove (25) is 0.2 mm to 0.3 mm greater than the width of the tube shell frame (12); The width of the welding isolation zone (30) is 0.15 mm to 0.3 mm.

4. The packaging structure of the high-performance IPM module according to claim 1, characterized in that: Also included is a preformed copper strip (15); A plurality of the pins (21) are connected to a plurality of corresponding pads of the power board (13) via the preformed copper tape (15).

5. The packaging structure of the high-performance IPM module according to claim 4, characterized in that: The preformed copper strip (15) comprises: a copper strip welding portion (18), a copper strip bending portion (19) and a plurality of copper strip welding holes (20); The plurality of copper strip welding holes (20) are used to pass through the plurality of tube pins (21) one by one and be welded with the plurality of tube pins (21) one by one; The copper strip welding portion (18) is connected to the end of the second part of the copper strip bending portion (19), and is used for welding on a plurality of corresponding welding pads of the power board (13).

6. The packaging structure of the high-performance IPM module according to claim 5, characterized in that: The inner end surface of the tube pin (21) is provided with a tube pin welding column (28), and the diameter of the copper strip welding hole (20) is larger than the diameter of the tube pin welding column (28) and smaller than the diameter of the tube pin (21); The copper strip welding hole (20) is used to pass through the pin welding column (28) of the pin (21), and the copper strip welding hole (20) contacts and welds with the pin welding column (28).

7. The packaging structure of the high-performance IPM module according to claim 1, characterized in that: The outer end of the insulator (29) protrudes from the outer side wall of the tube shell frame (12) along the tube pin (21), and the inner end is flush with the inner side wall of the tube shell frame (12); The packaging structure of the high-performance IPM module further includes: an insulating film (23) and a high-voltage silicone gel (24); The insulating film (23) is used for bonding to the inner side wall of the tube shell frame (12), and is provided with an insulating film through hole (26) for passing the tube pin (21); The high-voltage silicone gel (24) is used to coat at least the edge of the insulating film (23) and between the edge of the insulating film through hole (26) and the pin (21).

8. The packaging structure of the high-performance IPM module according to claim 7, characterized in that: The number of the insulating films (23) is two; The two insulating films (23) are respectively bonded to two opposite inner side walls of the tube shell frame (12), and are each provided with a plurality of insulating film through holes (26) for passing through a plurality of the tube pins (21) on the same side one by one; The high-voltage silicone gel (24) is used to be coated at least on the edges of the two insulating films (23) and between the edge of each insulating film through hole (26) and the corresponding pin (21).

9. The packaging structure of the high-performance IPM module according to claim 8, characterized in that: Each of the insulating films (23) is provided with a plurality of insulating film slits (27) distributed in parallel, and one side of the plurality of insulating film slits (27) is connected one by one with the plurality of through holes of the insulating film (23), and the other side is connected with the upper edge or the lower edge of the insulating film (23); The high-voltage silicone gel (24) is also used to coat the gap of each insulating film cut (27) of each insulating film (23).

10. A method for manufacturing a packaging structure of a high-performance IPM module, characterized in that: Used to manufacture the packaging structure of the high-performance IPM module as claimed in claim 6, wherein the outer end of the insulator (29) of the packaging structure of the high-performance IPM module protrudes from the outer side wall of the tube shell frame (12) along the tube pin (21), and the inner end is flush with the inner side wall of the tube shell frame (12); The packaging structure of the high-performance IPM module further includes: an insulating film (23) and a high-voltage silicone gel (24); The insulating film (23) is used for bonding to the inner side wall of the tube shell frame (12), and is provided with an insulating film through hole (26) for passing the tube pin (21); The high-voltage silicone gel (24) is used to coat at least the edge of the insulating film (23) and between the edge of the insulating film through hole (26) and the pin (21); The production method comprises: S1. Provide the tube shell base, tube shell frame, cover, power board, signal board, insulator, pin, preformed copper tape, insulation film and high-voltage silicone gel; S2, welding the tube shell base and the tube shell frame; S3, mounting: mounting the power board on the tube shell base, mounting the power board components on the surface of the power board, inserting the copper tape welding holes of the preformed copper tape into the pin welding columns of the corresponding pins, and mounting the copper tape welding part on the corresponding pads of the power board; S4, reflow soldering: solder the power board to the base of the tube shell, solder the power board components to the surface of the power board, and solder the copper strip soldering part to the corresponding soldering pad of the power board; S5, completing the welding of the copper tape welding holes of the preformed copper tape and the pin welding columns of the corresponding pins; S6, complete welding cleaning; S7, attaching the insulating film to the inner wall of the tube shell frame; S8, complete the assembly of the signal board, and fix the signal board assembly on the tube shell base; S9, bonding the signal board and the power board; S10, coating the high-voltage silicone gel on the edge of the insulating film, between the edge of the through hole of the insulating film and the pin, and between the high-voltage assembly area and the low-voltage assembly area of ​​the power board; S11. Install the cover to complete the packaging.

Images