Laminated busbar insulation film hot press forming process and forming device

Abstract

The present application relates to the technical field of laminated busbar manufacturing, in particular to a laminated busbar insulation film hot-pressing forming process and a forming device, comprising the following steps: laminating into a mold: stacking an upper conductive busbar, an insulation film and a lower conductive busbar in order and placing them into a hot-pressing mold; hot-pressing and laminating: heating the mold and applying a mold closing pressure to activate the adhesive layer of the insulation film; in the hot-pressing process, a first pressure is applied to the main plane area of the ear part, and a second pressure, which is smaller than the first pressure, is applied to the bending angle and / or edge area of the ear part. In the hot-pressing and laminating process, the first pressure is applied to the main plane area of the ear part, and the second pressure, which is smaller than the first pressure, is applied to the bending angle and / or edge area of the ear part, thereby realizing differential pressure application to different structural areas on the same ear part and solving the problem of glue extrusion, excessively thin or missing adhesive layer in the bending angle / edge area caused by stress concentration in the traditional uniform pressure process.

Description

Technical Field

[0001] This invention relates to the field of laminated busbar manufacturing technology, specifically to the hot pressing forming process of laminated busbar insulating film and the hot pressing forming device for laminated busbar insulating film. Background Technology

[0002] Laminated busbars are conductive connection components widely used in power electronic equipment. They are typically composed of an upper conductive busbar, a lower conductive busbar, and an insulating film sandwiched between them, bonded together via a hot-pressing process. During hot pressing, the stacked conductive busbars and insulating film are placed in a mold, heated, and subjected to clamping pressure. This causes the adhesive layer on the surface of the insulating film to melt, flow, and fully wet the surface of the conductive busbars. After cooling and solidification, a reliable interlayer insulating bond is formed.

[0003] Conductive busbars typically have lugs extending outward from the main body. These lugs serve as electrical connection terminals and include both flat planar areas and bends and / or edges formed by stamping, bending, or other forming processes. In traditional hot pressing processes, the mold applies uniform pressure to the entire pressure-bearing surface of the lugs. However, due to the geometric curvature changes in the bends and edges, stress concentration easily occurs under uniform high pressure, leading to excessive extrusion of the molten adhesive in these areas. This results in defects such as excessively thin adhesive layers or even missing adhesive, severely reducing the insulation withstand voltage and long-term reliability of these areas. Conversely, reducing the overall pressure to accommodate the bends / edges leads to insufficient adhesive wetting and inadequate bonding strength in the planar areas of the main body. Summary of the Invention

[0004] This invention addresses the problems in the prior art by providing a hot-pressing molding process and apparatus for laminated busbar insulating film. The specific technical solution is as follows: On one hand, the present invention provides a hot-pressing molding process for laminated busbar insulating film, used to hot-press and bond an upper conductive busbar, a lower conductive busbar, and an insulating film placed between them, wherein the upper conductive busbar and the lower conductive busbar have interconnected edge lugs, comprising the following steps: Stacking and molding: Stack the upper conductive busbar, insulating film and lower conductive busbar in sequence and place them into the hot press mold; Hot pressing lamination: The mold is heated and a mold closing pressure is applied to activate the adhesive layer of the insulating film. During the hot pressing process, the main planar area of ​​the ear is controlled to bear a first pressure, while the corner and / or edge area of ​​the ear is controlled to bear a second pressure, the second pressure being less than the first pressure. Pressure holding and cooling curing: Cool the mold while maintaining the first pressure and the second pressure to cure the adhesive layer and form an interlayer insulating bond.

[0005] As a further technical solution of the present invention, in the hot pressing lamination step, the heating temperature is 120℃~170℃ and the holding time is 3min~10min.

[0006] As a further technical solution of the present invention, before the stacking and molding step, a pretreatment step is also included: the bonding surfaces of the upper and lower conductive busbars are degreased and deburred, and the adhesive insulating film is cut to match the size of the bonding area.

[0007] On the other hand, the present invention also provides a hot pressing forming apparatus for laminated busbar insulating film, used to implement the hot pressing forming process of laminated busbar insulating film as described in any of the above technical solutions, including a mold, the mold including an upper mold, a lower mold, a cavity and a pressure unit, the upper mold and the lower mold being able to open and close relative to each other, the cavity being formed when the mold is closed and its shape matching the shape of the busbar, the pressure unit being disposed on the upper mold and / or the lower mold, used to apply pressure to the busbar in the closed state; The pressure application unit includes multiple pressure application components, each including a pressure rod and an elastic pressure member. The pressure rod is telescopically configured and presses against the busbar under the action of the elastic pressure member. During hot pressing of the mold, the pressure unit applies a first pressure to the main planar area of ​​the busbar ear and a second pressure to the corner and / or edge area of ​​the ear, the second pressure being less than the first pressure.

[0008] As a further technical solution of the present invention, the pressure application assembly further includes a sliding cavity, the pressure rod is slidably engaged with the sliding cavity, and the elastic pressure application member is connected between the sliding cavity and the pressure rod; in the mold closing state, the compression amount of the elastic pressure application member in all the pressure application assemblies is the same; In each of the pressure-applying components, the elastic coefficient k1 of the elastic pressure-applying member corresponding to the main body planar region is greater than the elastic coefficient k2 of the elastic pressure-applying member corresponding to the corner and / or edge region.

[0009] As a further technical solution of the present invention, it also includes a spacer layer disposed on the pressure surface of the busbar, the spacer layer including a support layer corresponding to the main planar area and a deformation layer corresponding to the corner and / or edge area; the deformation layer is configured to change shape when the mold temperature rises to a preset first temperature during the hot pressing process, so that the clamping force of the pressure bar on the busbar in the corresponding area is reduced, thereby forming the second pressure.

[0010] As a further technical solution of the present invention, the first temperature is 100℃~120℃.

[0011] As a further technical solution of the present invention, the support layer is a high-temperature resistant polymer coating, metal foil or ceramic coating; the deformation layer is a low-melting-point metal coating, wax-based coating, thermal sublimation material coating or thermal decomposition foaming coating.

[0012] As a further technical solution of the present invention, the pressure bar is a stepped structure, and its diameter at the end facing the busbar is greater than the diameter at the end away from the busbar.

[0013] As a further technical solution of the present invention, the elastic pressure-applying component is a helical spring, a disc spring, or an elastic rubber component.

[0014] The beneficial effects of this invention are as follows: (1) In this invention, during the hot pressing process, a first pressure is applied to the main planar area of ​​the ear, and a second pressure less than the first pressure is applied to the corner and / or edge area of ​​the ear. This achieves differentiated pressure on different structural areas of the same ear, solves the problem of adhesive being squeezed out, the adhesive layer being too thin or missing due to stress concentration in the corner / edge area in the traditional pressure equalization process, ensures that the minimum thickness of the adhesive layer in the corner / edge area meets the insulation withstand voltage requirements, and at the same time ensures the bonding strength and thickness accuracy of the main planar area.

[0015] (2) In this invention, by using a pressure assembly consisting of a pressure bar and an elastic pressure member, and setting the elastic pressure member corresponding to the main body plane area to have an elastic coefficient greater than that of the elastic pressure member corresponding to the bend and / or edge area, it is realized that under the condition that all elastic pressure members have the same compression amount in the mold closing state, the differential first pressure and second pressure can be output automatically and reliably. This solves the problem that traditional pressure equalization molds cannot apply different pressures to different areas of the same workpiece in the same process. Pressure zoning can be achieved without additional pressure adjustment or control system. The structure is simple and the operation is reliable.

[0016] (3) In this invention, by pre-setting a spacer layer on the pressure surface of the busbar, and taking advantage of the characteristic that the deformation layer of the corresponding bend and / or edge area changes shape and reduces support capacity under hot pressing temperature, the compression amount of the elastic pressure member of the pressure bar in this area is passively reduced, realizing the automatic conversion from initial uniform pressure to differentiated pressure during hot pressing. This solves the problem of limited mold versatility caused by the need to pre-set different elastic coefficients, enabling the same set of molds to adapt to the pressure differentiation requirements of different specifications of busbars, and improving the versatility and process flexibility of the device. Attached Figure Description

[0017] Figure 1 A schematic diagram of the hot pressing forming device for the laminated busbar insulating film in Embodiment 2 is shown. Figure 2 A schematic diagram of the pressure application unit in Embodiment 2 is shown; Figure 3 A schematic diagram of the hot pressing forming device for the laminated busbar insulating film in Embodiment 3 is shown. Figure 4 A schematic diagram of the pressure unit in Embodiment 3 is shown. Attached image description: 100. Upper mold; 110. Upper mold heating element; 200. Lower mold; 210. Lower mold heating element; 300, cavity; 400, Pressure unit; 410, Pressure assembly; 411, Sliding cavity; 412, Pressure rod; 413, Elastic pressure component; 420, Spacer layer; 421, Support layer; 422, Deformation layer. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0020] Example 1

[0021] This embodiment provides a hot-press forming process for laminated busbar insulating film, which is used to hot-press and bond the upper conductive busbar, the lower conductive busbar and the insulating film placed between them. It should be noted that the connection between the upper conductive busbar and the lower conductive busbar refers to the connection of the ears on their edges. The busbar ears are connection terminals that extend outward from the conductive busbar body. They have a flat main body area and bends or contour edges formed by stamping, bending, etc.

[0022] The process includes the following steps: Pre-treatment: Degrease and deburr the bonding surfaces of the upper and lower conductive busbars, and cut the adhesive insulating film to match the size of the bonding area; Stacking and molding: Stack the upper conductive busbar, insulating film and lower conductive busbar in sequence and place them into the hot press mold; Hot pressing lamination: The mold is heated and a mold closing pressure is applied to activate the adhesive layer of the insulating film; during the hot pressing process, the main planar area of ​​the ear is controlled to bear a first pressure, while the corner and / or edge area of ​​the ear is controlled to bear a second pressure, the second pressure being less than the first pressure; Pressure holding and cooling curing: Cool the mold while maintaining the first and second pressures to cure the adhesive layer and form an interlayer insulating bond; The core of this embodiment lies in the fact that, during the hot-pressing lamination process, instead of applying uniform pressure to the entire ear area, differentiated pressure is applied according to the structural characteristics of different areas of the ear. A larger first pressure is applied to the main planar area, while a smaller second pressure is applied to the corner and / or edge areas. This effectively solves the problem in traditional uniform pressure processes where stress concentration in corner / edge areas leads to the extrusion of adhesive, excessively thin adhesive layers, or even missing adhesive, while ensuring the bonding strength and thickness accuracy of the main planar area.

[0023] In this embodiment, the first pressure is 1MPa to 2MPa, and the second pressure is 0.5MPa to 0.8MPa. This ensures that the insulating film in the corner / edge areas is fully adhered and eliminates air bubbles, while also effectively preventing excessive extrusion of the adhesive and ensuring that the minimum thickness of the adhesive layer meets the insulation withstand voltage requirements.

[0024] In this embodiment, during the hot pressing lamination step, the heating temperature is 120℃~170℃ and the holding time is 3min~10min, to ensure that the adhesive layer is fully melted and wets the surface of the conductive busbar.

[0025] It should be noted that the core of the process in this embodiment lies in the technical means of "applying different pressures to different areas of the ear." The specific method for achieving this differentiated pressure is not limited to this embodiment. In practice, it can be achieved in various ways: for example, by the cooperation of a pre-set rigid pressure surface and a flexible pressure unit in the mold; or by pre-setting a partitioned support layer on the surface of the conductive busbar, utilizing the material's state change at hot-pressing temperature to automatically achieve pressure partitioning; or by other equivalent mechanical, material, or control methods. Regardless of the specific implementation method, as long as it achieves pressure differentiation between the planar area and the corner / edge area of ​​the ear body during hot-pressing, and the second pressure is less than the first pressure, it should fall within the protection scope of this process.

[0026] Example 2

[0027] This embodiment provides a hot pressing forming apparatus for laminated busbar insulating film, which is applied to the hot pressing forming process of laminated busbar insulating film in Embodiment 1, such as... Figure 1 and Figure 2As shown, the device includes a mold, which comprises an upper mold 100, a lower mold 200, a cavity 300, and a pressure unit 400. The upper mold 100 and the lower mold 200 are openable and closeable relative to each other. The upper mold 100 is provided with an upper mold heating element 110, and the lower mold 200 is provided with a lower mold heating element 210. The upper mold heating element 110 and the lower mold heating element 210 cooperate to heat the mold after it is closed. The cavity 300 is formed when the upper mold 100 and the lower mold 200 are closed, and the shape of the cavity 300 matches the shape of the compressed busbar. The pressure unit 400 is disposed on the upper mold 100, and the pressure unit 400 applies pressure to the cavity 300 in the closed state. The busbar is pressurized, and the pressurizing unit 400 includes several sets of pressurizing components 410, which cover the pressurized surface of the busbar. Each pressurizing component 410 includes a sliding cavity 411, a pressure rod 412, and an elastic pressurizing element 413. The pressure rod 412 is slidably engaged with the sliding cavity 411, and the elastic pressurizing element 413 is connected between the sliding cavity 411 and the pressure rod 412. In each pressurizing component 410, the elastic coefficient of the elastic pressurizing element 413 corresponding to the main planar area of ​​the busbar is k1, and the elastic coefficient of the elastic pressurizing element 413 corresponding to the bend and / or edge area of ​​the busbar is k2, where k1 > k2.

[0028] Based on the above, the stacked upper conductive busbar, insulating film, and lower conductive busbar are placed on the lower mold 200, and the upper mold 100 is closed downwards. After the mold is closed, the ends of the pressure rods 412 in each pressure component 410 on the upper mold 100 contact the pressure surface of the busbar. At this time, each pressure rod 412 generates a certain amount of compression relative to the corresponding sliding cavity 411. The elastic pressure member 413 connected between the sliding cavity 411 and the pressure rod 412 is compressed, generating a clamping force and driving the pressure rod 412 to press the busbar. Since all the elastic pressure members 413 have the same amount of compression at this time, but the elastic coefficient k1 of the elastic pressure member 413 corresponding to the main plane area of ​​the busbar is greater than the elastic coefficient k2 of the elastic pressure member 413 corresponding to the corner and / or edge area, the elastic pressure member 413 in the k1 area generates a larger elastic restoring force, thereby applying a higher first pressure to the main plane area of ​​the busbar through the pressure rod 412, while the restoring force generated by the elastic pressure member 413 in the k2 area is smaller, applying a lower second pressure to the corner and / or edge area.

[0029] In this embodiment, the mold cavity 300 and the pressure rod end face of the pressure unit 400 together form a plane or curved surface that matches the shape of the pressure surface of the busbar when the mold is closed, so as to ensure the consistency of the compression amount.

[0030] In this embodiment, the sliding cavity 411 is directly formed on the upper mold 100; or, the sliding cavity 411 is formed in a sliding seat installed on the upper mold 100.

[0031] In this embodiment, the pressure rod 412 has a stepped structure, with the diameter of the end facing the busbar being greater than the diameter of the end away from the busbar.

[0032] In this embodiment, the elastic pressure-applying component 413 is one of a helical spring, a disc spring, or an elastic rubber component.

[0033] Example 3

[0034] This embodiment provides a hot pressing forming apparatus for laminated busbar insulating film, which is applied to the hot pressing forming process of laminated busbar insulating film in Embodiment 1, such as... Figure 3 and Figure 4 As shown, the device includes a mold, which includes an upper mold 100, a lower mold 200, a cavity 300, and a pressure unit 400. The upper mold 100 and the lower mold 200 can open and close relative to each other. The upper mold 100 is provided with an upper mold heating element 110, and the lower mold 200 is provided with a lower mold heating element 210. The upper mold heating element 110 and the lower mold heating element 210 cooperate to heat the mold after it is closed. The cavity 300 is formed when the upper mold 100 and the lower mold 200 are closed, and the shape of the cavity 300 matches the shape of the compressed busbar. The pressure unit 400 is disposed on the lower mold 200. The pressure unit 400 applies pressure to the busbar in the closed state. The pressure unit 400 includes several sets of pressure components 410, which cover the pressure surface of the busbar. The pressure component 410 includes a sliding cavity 4. 11. A pressure rod 412 and an elastic pressure member 413, wherein the pressure rod 412 is slidably engaged with the sliding cavity 411, and the elastic pressure member 413 is connected between the sliding cavity 411 and the pressure rod 412; the pressure application assembly 410 further includes a spacer layer 420 preset on the pressure surface of the busbar, the spacer layer 420 including a support layer 421 corresponding to the main body planar area and a deformation layer 422 corresponding to the corner and / or edge area, during the hot pressing process, when the mold temperature rises to a preset first temperature, the deformation layer 422 undergoes a shape change, driving the pressure rod 412 in the area corresponding to the deformation layer 422 to move toward the busbar, thereby reducing the compression amount of the elastic pressure member 413, thereby reducing the clamping force of the pressure application assembly 410 on the busbar in this area, the first temperature being 100℃~120℃.

[0035] Based on the above, the upper conductive busbar, insulating film, and lower conductive busbar are stacked sequentially. A spacer layer 420 is pre-set on the pressure-bearing surface of the lower conductive busbar, a support layer 421 is set on the corresponding busbar main body plane area, and a deformation layer 422 is set on the corresponding corner and / or edge area. Then, the stacked workpiece, together with the spacer layer 420, is placed on the lower mold 200. The upper mold 100 closes downwards. After the mold closes, the ends of each pressure rod 412 in the pressure unit 400 on the lower mold 200 contact the lower surface of the spacer layer 420. At this time, all pressure rods 412 are compressed into the sliding cavity 411, and the elastic pressure member 413 generates compression. A uniform first pressure is applied to the workpiece; the upper mold heating element 110 and the lower mold heating element 210 start heating the mold. When the mold temperature rises to the preset first temperature, the deformation layer 422 undergoes a shape change and the support capacity decreases. The upward reaction force on the pressure bar 412, which was originally compressed in the corner and / or edge area, decreases in this area. At this time, the elastic force of the elastic pressure element 413 will push the pressure bar 412 towards the mother row. This movement causes the compression of the elastic pressure element 413 to decrease, thereby reducing the clamping force applied by the pressure component 410 to the mother row in this area, and finally forming a smaller second pressure.

[0036] In this embodiment, the sliding cavity 411 is directly formed on the upper mold 100; or, the sliding cavity 411 is formed in a sliding seat installed on the upper mold 100.

[0037] In this embodiment, the pressure rod 412 has a stepped structure, with the diameter of the end facing the busbar being greater than the diameter of the end away from the busbar.

[0038] In this embodiment, the elastic pressure-applying component 413 is one of a helical spring, a disc spring, or an elastic rubber component.

[0039] In this embodiment, the support layer 421 is a high-temperature resistant polymer coating, metal foil, or ceramic coating, which does not undergo volume change during the entire hot pressing process; the deformation layer 422 is a low-melting-point metal coating, wax-based coating, thermal sublimation material coating, or thermal decomposition foaming coating, which reduces the supporting force during the hot pressing process.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. A hot-pressing molding process for laminated busbar insulating film, used to hot-press and bond an upper conductive busbar, a lower conductive busbar, and an insulating film placed between them, wherein the upper conductive busbar and the lower conductive busbar have interconnected edge lugs, characterized in that... Includes the following steps: Stacking and molding: Stack the upper conductive busbar, insulating film and lower conductive busbar in sequence and place them into the hot press mold; Hot pressing lamination: The mold is heated and a mold closing pressure is applied to activate the adhesive layer of the insulating film. During the hot pressing process, the main planar area of ​​the ear is controlled to bear a first pressure, while the corner and / or edge area of ​​the ear is controlled to bear a second pressure, the second pressure being less than the first pressure. Pressure holding and cooling curing: Cool the mold while maintaining the first pressure and the second pressure to cure the adhesive layer and form an interlayer insulating bond.

2. The hot pressing molding process for laminated busbar insulating film according to claim 1, characterized in that: In the hot pressing lamination step, the heating temperature is 120℃~170℃, and the holding time is 3min~10min.

3. The hot pressing molding process for laminated busbar insulating film according to claim 1, characterized in that: Before the stacking and molding step, a pretreatment step is also included: the bonding surfaces of the upper and lower conductive busbars are degreased and deburred, and the adhesive insulating film is cut to match the size of the bonding area.

4. A hot-pressing forming apparatus for laminated busbar insulating film, used to implement the hot-pressing forming process of laminated busbar insulating film according to any one of claims 1-3, characterized in that: The mold includes an upper mold, a lower mold, a cavity, and a pressure unit. The upper mold and the lower mold can be opened and closed relative to each other. The cavity is formed when the mold is closed and its shape matches the shape of the busbar. The pressure unit is disposed on the upper mold and / or the lower mold and is used to apply pressure to the busbar when the mold is closed. The pressure application unit includes multiple pressure application components, each including a pressure rod and an elastic pressure member. The pressure rod is telescopically configured and presses against the busbar under the action of the elastic pressure member. During hot pressing of the mold, the pressure unit applies a first pressure to the main planar area of ​​the busbar ear and a second pressure to the corner and / or edge area of ​​the ear, the second pressure being less than the first pressure.

5. The hot pressing forming apparatus for laminated busbar insulating film according to claim 4, characterized in that: The pressure application assembly further includes a sliding cavity, the pressure rod is slidably engaged with the sliding cavity, and the elastic pressure member is connected between the sliding cavity and the pressure rod; in the mold closing state, the compression amount of the elastic pressure member in all the pressure application assemblies is the same; In each of the pressure-applying components, the elastic coefficient k1 of the elastic pressure-applying member corresponding to the main body planar region is greater than the elastic coefficient k2 of the elastic pressure-applying member corresponding to the corner and / or edge region.

6. The hot pressing forming apparatus for laminated busbar insulating film according to claim 4, characterized in that: It also includes a spacer layer disposed on the pressure surface of the busbar, the spacer layer comprising a support layer corresponding to the main planar area and a deformation layer corresponding to the corner and / or edge area; the deformation layer is configured to undergo a shape change during the hot pressing process when the mold temperature rises to a preset first temperature, thereby reducing the clamping force of the pressure bar on the busbar in the corresponding area, thus forming the second pressure.

7. The hot pressing forming apparatus for laminated busbar insulating film according to claim 5, characterized in that: The first temperature is 100℃~120℃.

8. The hot pressing forming apparatus for laminated busbar insulating film according to claim 5, characterized in that: The support layer is a high-temperature resistant polymer coating, metal foil, or ceramic coating; the deformation layer is a low-melting-point metal coating, wax-based coating, thermal sublimation material coating, or thermal decomposition foaming coating.

9. The hot pressing forming apparatus for laminated busbar insulating film according to any one of claims 4-8, characterized in that: The pressure bar has a stepped structure, with its diameter at the end facing the busbar being greater than that at the end away from the busbar.

10. The hot pressing forming apparatus for laminated busbar insulating film according to any one of claims 4-8, characterized in that: The elastic pressure-applying component is a helical spring, a disc spring, or an elastic rubber component.

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