Filling and sealing mold of power module

Abstract

The utility model relates to the technical field of power module packaging, in particular to a potting mold of a power module. The utility model discloses a filling and sealing die. The filling and sealing die sequentially comprises a lower die holder, an elastic device, a sealing cushion block, a die cavity, an upper sealing gasket and an upper die holder, acting force close to each other is applied between the upper die holder and the lower die holder, so that all parts between the upper die holder and the lower die holder are tightly attached, and the elastic device and the sealing gasket are compressed; the upper sealing gasket is used for protecting the tail ends of the pins and preventing silica gel from being attached to the lower portions of the pins. The lower sealing gasket is used for protecting the lower surface of the insulating layer and preventing silica gel from permeating into the lower surface of the insulating layer. The whole device can effectively solve the problems that the periphery of the liquid level of packaging silica gel is high, the middle of the liquid level of packaging silica gel is low, and silica gel is attached to the lower portions of the pins. The problem that the lower surface of the insulating layer is polluted by leakage of silica gel can be avoided; and no fabrication hole is left on the packaged power module.

Description

Technical Field

[0001] The utility model relates to the technical field of power module packaging, in particular to a potting mold of a power module. Background Art

[0002] IGBT module is the main device in the electric drive circuit. It generates a huge amount of heat when working. It works in a working environment of 100-120 degrees Celsius for a long time. When it stops working, it returns to normal temperature. The huge and frequent temperature changes make it extremely deformed by heat. This requires the electrical protection material of the IGBT module to have a strong ability to resist thermal deformation, but the commonly used packaging materials such as resin, polyethylene, and polypropylene cannot meet such requirements. Therefore, the IGBT module usually uses elastic liquid silicone to pot its circuit and then solidify the silicone. However, in the prior art, soft silicone cannot be used alone for potting IGBT modules because of its high viscosity. Instead, the silicone is poured into the plastic shell to avoid contact and adhesion of the silicone with other objects.

[0003] like Figure 1 As shown in the figure, in the existing bare silicone potting IGBT packaging process, the potting process requires that the bonding wire needs to be completely immersed in the potting glue, the upper end of the pin should be completely exposed from the glue surface, and the potting glue cannot cover or contaminate the lower surface of the insulation layer and the surfaces of the upper end of the pin. Because the silicone used has good fluidity and adhesion, if the potting glue is simply surrounded during the actual potting process, the silicone will adhere to the fixture wall. Figure 2 The state shown is: the liquid surface is higher around and lower in the middle, and there is silicone attached to the bottom of the pin; there is no good seal under the insulation layer, which causes silicone to leak and contaminate the lower surface of the insulation layer. Both of these shortcomings seriously do not meet the application requirements. For example, the technology disclosed in the application number "201510375146.9" and the name "A method for injection molding of plastic-sealed IPM and plastic-sealed IPM" is only suitable for occasions where the packaging material is plastic (such as epoxy resin). When the silicone is cured, gas will be released and the fully enclosed cavity solution cannot be used, and this solution will leave process holes on the finished product.

[0004] Based on the above defects, a new power module packaging mold is proposed to solve the following problems in the existing technology: "the packaging silicone liquid level is higher around and lower in the middle, and silicone is attached to the bottom of the pins", "silicone will leak and contaminate the lower surface of the insulating layer" and "process holes are left on the finished product". Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides a potting mold for a power module, which solves the problem that silica gel may contaminate the pins and the insulating layer of the power module by using a sealing gasket.

[0006] The utility model discloses a potting mold of a power module through an embodiment, including an upper mold base, a lower mold base and a mold cavity, an upper sealing gasket, a lower sealing gasket, a sealing gasket block and an elastic device. Among them, a first limiting groove is provided on the upper surface of the lower mold base, a second limiting groove is provided in the first limiting groove, a first air vent is provided in the second limiting groove, a first casting port is provided on the upper mold base, a second casting port is provided on the upper sealing gasket, a second air vent is provided on the lower sealing gasket, and a third air vent is provided on the sealing gasket block. The elastic device is provided in the second limiting groove, the sealing gasket block is provided in the first limiting groove, the upper sealing gasket is provided between the upper mold base and the mold cavity, and the lower sealing gasket is provided between the lower mold base and the mold cavity. The lower mold base, the lower sealing gasket, the mold cavity, the upper sealing gasket and the upper mold base are fixedly connected to form the potting mold of the power module.

[0007] Furthermore, the lower mold base, lower sealing gasket, mold cavity, upper sealing gasket and upper mold base are all provided with pin holes, and the lower mold base, lower sealing gasket, mold cavity, upper sealing gasket and upper mold base are fixed by positioning pins and pin holes to form a potting mold for the power module.

[0008] It is worth noting that the pin holes opened on the lower mold base, lower sealing gasket, mold cavity, upper sealing gasket and upper mold base can be fixed by passing a positioning pin through the pin holes at the same position when the components form the potting mold of the power module.

[0009] Furthermore, chamfers are provided on the four edges of the first limiting groove, and the chamfers can avoid cutting the lower sealing pad.

[0010] Furthermore, the sealing gasket block is made of hard material, and the edges of the sealing gasket block are provided with chamfers. Similarly, the chamfers can avoid cutting the lower sealing gasket.

[0011] Furthermore, the elastic device is a disc spring, the fingers of which form a protrusion in the direction of the sealing gasket, and the fingers of the disc spring protrude upward, bend downward when subjected to force, and provide elastic force to support the sealing gasket.

[0012] Furthermore, the size of the lower end of the mold cavity is smaller than that of the upper end, which can facilitate the removal of the solidified silicone body.

[0013] Furthermore, the lower sealing gasket and the upper sealing gasket are made of polyurethane material. Polyurethane material has good elasticity and is not easy to bond with silicone. The mold cavity is made of Teflon material, which has good rigidity and is not easy to bond with silicone, and can facilitate demoulding of the encapsulated power module. The sealing gasket block is made of hard material, preferably, the sealing gasket block is made of hard aluminum alloy material.

[0014] Furthermore, the upper die base and the lower die base are made of high-strength steel.

[0015] Furthermore, the lower mold base, the lower sealing gasket, the mold cavity, the upper sealing gasket and the upper mold base are all provided with two pin holes, and the two pin holes can play a better fixing role, ensure the position consistency of these components, and make the entire mold structure more stable.

[0016] The technical principle of the utility model is: a force is applied between the upper and lower mold bases to bring them closer to each other, and positioning pins are used to ensure the position consistency of these parts, so that all parts between the upper and lower mold bases are kept in close contact, and the elastic device and the sealing gasket are compressed; wherein the upper sealing gasket is used to protect the end of the pin to prevent silicone from adhering to the bottom of the pin; the lower sealing gasket is used to protect the lower surface of the insulating layer to prevent silicone from penetrating into the lower surface of the insulating layer; the sealing gasket block evenly applies the elastic force of the elastic device to the area of ​​the lower sealing gasket located at the bottom of the insulating layer, ensuring that the lower sealing gasket is in close contact with the lower surface of the insulating layer while preventing the insulating layer from being damaged under the force between the upper and lower mold bases. The first air vent, the second air vent and the third air vent are all used to release the air in the area below the lower sealing gasket in the vacuum degassing process step; the first casting port and the second casting port facilitate casting silicone into the cavity inside the mold.

[0017] Compared with the prior art, the utility model has the following beneficial effects: after the power module is packaged, it can effectively avoid the problem that the packaging silicone liquid level is higher around and lower in the middle and silicone is attached under the pins; it can also avoid the problem of silicone leakage and contamination of the lower surface of the insulating layer; and it will not leave process holes on the packaged power module. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the utility model and facilitate further understanding of the technical effects, technical features and purposes of the utility model, the utility model is described in detail below in conjunction with the accompanying drawings. The accompanying drawings constitute an essential part of the specification and are used together with the embodiments of the utility model to illustrate the technical solution of the utility model, but do not constitute a limitation to the utility model.

[0019] Figure 1 This is a schematic diagram of the existing packaging process mentioned in the background technology of this utility model. Figure 1 ;

[0020] Figure 2 This is a schematic diagram of the existing packaging process mentioned in the background technology of this utility model. Figure 2 ;

[0021] Figure 3 It is a schematic diagram of the potting mold recorded in the utility model;

[0022] Figure 4 It is a schematic diagram of the lower mold base of the potting mold recorded in the utility model;

[0023] Figure 5A schematic diagram of a sealing gasket of a potting mold described in the utility model;

[0024] Figure 6 It is a cross-sectional view of the potting mold recorded in the utility model;

[0025] Among them, 1-upper mold base, 2-lower mold base, 3-mold cavity, 4-upper sealing gasket, 5-lower sealing gasket, 6-sealing gasket block, 7-elastic device, 21-first limiting groove, 22-second limiting groove, 23-first air hole, 24-chamfer, 11-first casting port, 41-second casting port, 51-second air hole, 61-third air hole, 62-chamfer, 8-pin hole, 9-locating pin. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described below are only for explaining the technical solution of the present invention, rather than for limiting the present invention. In addition, the parts described in the embodiments or drawings are only examples of the relevant parts of the present invention, rather than the entirety of the present invention. At the same time, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field should naturally belong to the protection scope of the present invention.

[0027] like Figure 3-6 As shown, the utility model proposes a potting mold for a power module through the following embodiments, including an upper mold base 1, a lower mold base 2, a mold cavity 3, an upper sealing gasket 4, a lower sealing gasket 5, a sealing gasket block 6 and an elastic device 7. Among them, a first limiting groove 21 is provided on the upper surface of the lower mold base 2, a second limiting groove 22 is provided in the first limiting groove 21, a first air vent 23 is provided in the second limiting groove 22, a first casting port 11 is provided on the upper mold base 1, a second casting port 41 is provided on the upper sealing gasket 4, a second air vent 51 is provided on the lower sealing gasket 5, and a third air vent 61 is provided on the sealing gasket block 6. The elastic device 7 is arranged in the second limiting groove 22, the sealing gasket block 6 is arranged in the first limiting groove 21, the upper sealing gasket 4 is arranged between the upper mold base 1 and the mold cavity 3, and the lower sealing gasket 5 is arranged between the lower mold base 2 and the mold cavity 3. The lower mold base 2, the lower sealing gasket 5, the mold cavity 3, the upper sealing gasket 4 and the upper mold base 1 are all provided with pin holes 8, and the lower mold base 2, the lower sealing gasket 5, the mold cavity 3, the upper sealing gasket 4 and the upper mold base 1 are fixed by positioning pins 9 and pin holes 8 to form a potting mold for the power module.

[0028] like Figure 3 As shown, the pin holes opened on the lower mold base 2, the lower sealing gasket 5, the mold cavity 3, the upper sealing gasket 4 and the upper mold base 1 can be fixed by passing a positioning pin through the pin holes at the same position when the components form the potting mold of the power module, which can ensure the position consistency of these components and make the entire mold structure more stable.

[0029] In this embodiment, if Figure 4 As shown, the edges around the first limiting groove 21 on the lower die base 2 are also provided with chamfers 24 , and the chamfers 24 can avoid cutting the lower sealing gasket 5 .

[0030] In this embodiment, if Figure 5 As shown, the sealing gasket 6 is made of hard material, and the edges of the sealing gasket 6 are provided with chamfers 62. Similarly, the chamfers 62 can avoid cutting the lower sealing gasket 5.

[0031] In this embodiment, the elastic device 7 is a disc spring, the fingers of which form a protrusion in the direction of the sealing gasket 6. The fingers of the disc spring protrude upward, bend downward when subjected to force, and provide elastic force to support the sealing gasket 6.

[0032] In this embodiment, the lower sealing pad 6 and the upper sealing pad 4 are made of polyurethane material; polyurethane material has good elasticity and is not easy to bond with silicone. The lower end size of the mold cavity 3 is smaller than the upper end size, which can facilitate the removal of the cured silicone body; at the same time, the mold cavity 3 is made of Teflon material, which has good rigidity and is not easy to bond with silicone, which can facilitate the demolding of the encapsulated power module. The upper mold base 1 and the lower mold base 2 are made of high-strength steel.

[0033] In this embodiment, if Figure 3-5 As shown, the lower mold base 2, the lower sealing gasket 5, the mold cavity 3, the upper sealing gasket 4 and the upper mold base 1 are all provided with two pin holes, and the two pin holes can play a better fixing role, ensure the position consistency of these components, and make the entire mold structure more stable.

[0034] It should be noted that the above embodiments are only for more clearly illustrating the technical solution of the present invention. Those skilled in the art will understand that the implementation methods of the present invention are not limited to the above contents, and obvious changes, replacements or substitutions based on the above contents do not exceed the scope covered by the technical solution of the present invention; other implementation methods will naturally fall within the scope of the present invention without departing from the concept of the present invention.

Claims

1. A potting mold for a power module, comprising an upper mold base, a lower mold base and a mold cavity, characterized in that: It also includes an upper sealing pad, a lower sealing pad, a sealing pad block and an elastic device; The upper surface of the lower die base is provided with a first limiting groove, the first limiting groove is provided with a second limiting groove, the second limiting groove is provided with a first vent hole, the upper die base is provided with a first casting port, the upper sealing gasket is provided with a second casting port, the lower sealing gasket is provided with a second vent hole, and the sealing gasket block is provided with a third vent hole; The elastic device is arranged in the second limiting groove, the sealing pad block is arranged in the first limiting groove, the upper sealing pad is arranged between the upper die base and the die cavity body, and the lower sealing pad is arranged between the lower die base and the die cavity body; The lower mold base, the lower sealing gasket, the mold cavity, the upper sealing gasket and the upper mold base are fixedly connected to form a potting mold for the power module.

2. A potting mold for a power module according to claim 1, characterized in that: The lower mold base, lower sealing gasket, mold cavity, upper sealing gasket and upper mold base are all provided with pin holes, and the lower mold base, lower sealing gasket, mold cavity, upper sealing gasket and upper mold base are fixed by positioning pins and the pin holes to form a potting mold for the power module.

3. The potting mold for a power module according to claim 1, characterized in that: The edges around the first limiting groove are also chamfered.

4. The potting mold for a power module according to claim 1, characterized in that: The sealing pad is made of hard material, and the edges of the sealing pad are provided with chamfers.

5. The potting mold for a power module according to claim 1, characterized in that: The elastic device comprises a disc spring, and the finger of the disc spring forms a protrusion in the opposite direction of the sealing gasket block.

6. The potting mold for a power module according to claim 1, characterized in that: The size of the lower end of the mold cavity of the mold cavity body is smaller than that of the upper end.

7. A potting mold for a power module according to any one of claims 1 to 6, characterized in that: The lower sealing pad and the upper sealing pad are made of polyurethane material; the sealing pad block is made of hard material, and the mold cavity is made of Teflon material.

8. A potting mold for a power module as claimed in claim 7, characterized in that: The sealing pad is made of hard aluminum alloy material.

9. A potting mold for a power module as claimed in claim 8, characterized in that: The upper die base and the lower die base are made of high-strength steel.

10. A potting mold for a power module according to any one of claims 1 to 6, characterized in that: The lower die base, the lower sealing pad, the die cavity, the upper sealing pad and the upper die base are all provided with at least two pin holes.

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