Composite solder piece-based IGBT package large-area welding device

Abstract

This utility model discloses a large-area welding device for IGBT packaging based on composite solder sheets, including a base plate, a liquid inlet tank, a solder sheet fixing component, an elastic pressure plate, a liner fixing component, a cover plate, and bolts. A liquid inlet is provided on one outer wall of the base plate, and a liquid outlet is provided on the other outer wall. The base plate contains a liquid inlet tank, a guide tank, and a spiral flow channel. This utility model adopts a structured design. The device solves the problem of thermal imbalance in large-area welding through an integrated thermal control design of the base plate. On one hand, the gradient truncated cone on the upper surface of the base plate precisely covers the composite solder sheet area. Combined with the integrated copper and molybdenum alloy structure, it avoids overheating at the center and underheating at the edges. On the other hand, the closed-loop cooling path of the liquid inlet tank, guide tank, spiral flow channel, and liquid outlet tank achieves uniform distribution of coolant, allowing the composite solder sheet to crystallize orderly from the edge to the center. Simultaneously, the integrated structure reduces splicing gaps, and the device has high positioning accuracy.

Description

Technical Field

[0001] This utility model relates to the field of composite solder pad technology, and in particular to a large-area welding device for IGBT packaging based on composite solder pads. Background Technology

[0002] With the surge in demand for high-power IGBT modules in fields such as new energy vehicles, photovoltaic inverters, and rail transit, the large-area welding process in the IGBT packaging stage has become a core bottleneck restricting module reliability and mass production efficiency. Currently, existing IGBT welding equipment still has the following technical pain points in large-area welding scenarios: First, the planar base plate heat transfer mode leads to excessively high heat flux density in the central area of ​​the composite solder sheet, which easily causes solder overmelting and loss, while the heat input in the edge area is insufficient, resulting in incomplete welding. The cooling system lacks a flow guiding and collection structure, and the uneven distribution of coolant leads to large fluctuations in the cooling rate. During the crystallization process of the composite solder sheet, internal stress is generated due to disordered grain growth, which causes weld layer cracks. Second, in terms of positioning accuracy, multi-layer tooling relies on multiple sets of independent fasteners for splicing, which leads to misalignment between the composite solder sheet and the DBC ceramic backing plate, resulting in bridging defects after welding. In terms of pressing method, rigid pressing is prone to causing the backing plate to warp or even crack. Utility Model Content

[0003] The purpose of this invention is to provide a large-area welding device for IGBT packaging based on composite solder pads, so as to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a large-area welding device for IGBT packaging based on composite solder sheet, including a base plate, an inlet is provided on one outer wall of the base plate, an outlet is provided on the other outer wall of the base plate, an inlet groove, a guide groove and a spiral flow channel are provided inside the base plate, and the spiral flow channel is connected to the guide groove, the inlet groove and the outlet groove.

[0005] As a further technical solution of this utility model, a gradient truncated cone is provided on the upper surface of the base plate.

[0006] As a further technical solution of this utility model, fixing pins are provided at the four corners of the base plate, and welding sheet fixing parts are provided on the upper surface of the base plate.

[0007] As a further technical solution of this utility model, a first fixing ring is provided at the position corresponding to the fixing pin of the welding sheet fixing component, a first through cavity is provided inside the welding sheet fixing component, and a liner fixing component is provided on the welding sheet fixing component.

[0008] As a further technical solution of this utility model, a second through cavity is provided on the liner fixing member, and a second fixing ring is provided at the position corresponding to the fixing pin of the liner fixing member.

[0009] As a further technical solution of this utility model, the upper surface of the liner fastener is provided with a first fixing hole, the upper surface of the liner fastener is provided with a cover plate, a third fixing ring is provided on the cover plate at the position corresponding to the fixing pin, and a second fixing hole is provided on the cover plate at the position corresponding to the first fixing hole.

[0010] As a further technical solution of this utility model, bolts are threaded into both the first fixing hole and the second fixing hole, and elastic pressure plates are sleeved on the bolts.

[0011] Compared with existing technologies, the beneficial effects achieved by this utility model are as follows: This utility model adopts a structured design. The device solves the problem of thermal imbalance in large-area welding through an integrated thermal control design of the base plate. On the one hand, the gradient truncated cone on the upper surface of the base plate precisely covers the composite welding sheet area, combined with the integrated copper and molybdenum alloy structure, avoiding overheating at the center and underheating at the edges. On the other hand, the closed-loop cooling pathway of the inlet tank, guide tank, spiral flow channel, and outlet tank achieves uniform distribution of coolant, allowing the composite welding sheet to crystallize orderly from the edge to the center. Simultaneously, the integrated structure reduces splicing gaps, and the device... In terms of positioning accuracy, the four corner fixing pins of the base plate form a coaxial positioning with the first fixing ring of the welding piece fixing component, the second fixing ring of the liner fixing component, and the third fixing ring of the cover plate, completely avoiding misalignment between the welding piece and the liner. In terms of pressing control, the bolts and elastic pressure plates are made of beryllium copper alloy, and the combination can achieve adjustable pressing force, which not only avoids the warping of the liner caused by rigid pressing, but also eliminates the risk of air leakage failure without relying on external vacuum equipment. In terms of mass production adaptability, the first through cavity of the welding piece fixing component and the second through cavity of the liner fixing component are preset with multiple compatible sizes, which can cover a variety of composite welding pieces and liners without changing the tooling as a whole. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is an exploded view of the structure of this utility model;

[0014] Figure 2 This is a three-dimensional structural diagram of the base plate of this utility model;

[0015] Figure 3 This is a top view sectional structural diagram of the base plate of this utility model.

[0016] In the diagram: 1. Base plate; 2. Liquid inlet; 3. Liquid inlet tank; 4. Guide channel; 5. Spiral flow channel; 6. Drainage tank; 7. Drainage outlet; 8. Gradient truncated cone; 9. Fixing pin; 10. Welding sheet fixing component; 11. First fixing ring; 12. Elastic pressure plate; 13. First through cavity; 14. Liner fixing component; 15. Second fixing ring; 16. Second through cavity; 17. First fixing hole; 18. Cover plate; 19. Third fixing ring; 20. Second fixing hole; 21. Bolt. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0018] Please see the appendix Figure 1 -Appendix Figure 3This utility model provides an embodiment of a large-area welding device for IGBT packaging based on composite solder sheets, comprising a base plate 1, an inlet 2 on one outer wall of the base plate 1, an outlet 7 on the other outer wall of the base plate 1, an inlet groove 3, a guide groove 4, and a spiral flow channel 5 inside the base plate 1, and the spiral flow channel 5 is connected to the guide groove 4, the inlet groove 3, and the outlet groove 6; a gradient truncated cone 8 is provided on the upper surface of the base plate 1 to ensure uniform heating of the composite solder sheet in the first through cavity 13. The base plate 1 has four fixing pins 9 at its four corners, and a welding sheet fixing component 10 is provided on the upper surface of the base plate 1. The fixing pins 9 are used to position the welding sheet fixing component 10, and the welding sheet fixing component 10 is used to support the composite welding sheet. A first fixing ring 11 is provided at the position of the fixing pin 9 on the welding sheet fixing component 10. A first through cavity 13 is provided inside the welding sheet fixing component 10. A liner fixing component 14 is provided on the welding sheet fixing component 10. The first fixing ring 11 cooperates with the fixing pin 9 to position the welding sheet fixing component 10, and the first through cavity 13 is used to support the composite welding sheet. For placing composite welding sheets; a second through cavity 16 is provided on the liner fixing member 14, and a second fixing ring 15 is provided on the liner fixing member 14 at the position corresponding to the fixing pin 9. The second through cavity 16 is used to place the IGBT liner and is aligned with the first through cavity 13. The second fixing ring 15 cooperates with the fixing pin 9 to position the liner fixing member 14; a first fixing hole 17 is provided on the upper surface of the liner fixing member 14, and a cover plate 18 is provided on the upper surface of the liner fixing member 14. The cover plate 18 is provided at the position corresponding to the fixing pin 9. A third fixing ring 19 is provided, and a second fixing hole 20 is provided at the position of the cover plate 18 corresponding to the first fixing hole 17. The third fixing ring 19 cooperates with the fixing pin 9 to position the cover plate 18. The first fixing hole 17 and the second fixing hole 20 are fitted with bolts 21. Bolts 21 are threaded into both the first fixing hole 17 and the second fixing hole 20. An elastic pressure plate 12 is sleeved on the bolt 21. The bolt 21 is used to fix the cover plate 18 and the liner plate fixing member 14. The elastic pressure plate 12 is used to apply uniform pressure to the liner plate.

[0019] Working Principle: Using this invention, firstly, the base plate 1 is placed horizontally on the welding platform. The fixing pins 9 at the four corners of the base plate 1 are used as positioning references. The welding sheet fixing member 10 is inserted into the fixing pins 9 through its corresponding first fixing ring 11, ensuring precise contact between the welding sheet fixing member 10 and the upper surface of the base plate 1. Then, the composite welding sheet is placed into the first through cavity 13 within the welding sheet fixing member 10, ensuring complete contact between the lower surface of the composite welding sheet and the gradient truncated cone 8 on the base plate 1. Next, the liner fixing member 14 is inserted into the fixing pins 9 through its second fixing ring 15, ensuring coaxial alignment between the second through cavity 16 of the liner fixing member 14 and the first through cavity 13. The IGBT liner is then placed into the second through cavity 16, ensuring precise alignment between the lower surface of the liner and the upper surface of the composite welding sheet. Finally, the cover plate is placed on top. 18. By fitting the third fixing ring 19 of the cover plate 18 onto the fixing pin 9, the second fixing hole 20 of the cover plate 18 is aligned with the first fixing hole 17 of the liner fixing member 14. The elastic pressure plate 12 is fitted onto the bolt 21, and then the bolt 21 is screwed into the first fixing hole 17 and the second fixing hole 20. The elastic deformation of the elastic pressure plate 12 applies uniform preload to the liner, completing the multi-layer coaxial fixing of the base plate 1, welding piece fixing member 10, liner fixing member 14, and cover plate 18, avoiding component misalignment during welding. The welding furnace is started and heated to the composite welding piece melting temperature. The heat is transferred to the main body of the base plate 1 through the welding platform. The gradient truncated cone 8 on the upper surface of the base plate 1 utilizes its structural characteristic of gradually changing dimensions from the center to the edge to efficiently and uniformly transfer heat from the base plate 1 to the first... The composite weld sheet within the through cavity 13, with its gradient design of the gradient truncated cone 8, compensates for differences in heat loss during large-area welding. This keeps the thermal conductivity deviation of different areas of the composite weld sheet within a controllable range, avoiding the problems of overheating and melting at the center and underheating and incomplete melting at the edges caused by traditional planar heat transfer. This ensures that the composite weld sheet melts synchronously as a whole, laying the foundation for reliable bonding with the liner plate. After the composite weld sheet has completely melted and initially wetted with the IGBT liner plate, the cooling system is activated. Coolant is introduced through the inlet 2 on one side of the outer wall of the base plate 1. The coolant first enters the inlet tank 3 within the base plate 1 for buffering and distribution, and then is evenly introduced into the spiral flow channel 5 through the guide channel 4. The spiral flow channel 5 covers the core welding area of ​​the base plate 1 and is spaced apart from the gradient truncated cone 8, which can efficiently absorb the heat from the base plate 1 and the gradient truncated cone 8. The residual heat from the cone 8 is used to lower the temperature of the composite welded sheet through heat exchange. The coolant that has absorbed heat is collected in the drain trough 6 inside the base plate 1 and discharged from the drain port 7 on the outer wall of the other side of the base plate 1, forming a closed-loop cooling path consisting of the inlet 2, inlet trough 3, guide trough 4, spiral flow channel 5, drain trough 6, and drain port 7. This achieves precise control of the cooling rate, guides the composite welded sheet to crystallize orderly from the edge to the center, reduces internal stress caused by disordered crystallization, and avoids weld layer cracks. During the cooling and crystallization process, the elastic pressure plate 12 connected by bolt 21 maintains an elastic compression state. Its deformation force can adapt to the slight dimensional changes of the liner and the composite welded sheet, ensuring that the two are always tightly fitted, squeezing out residual air in the weld layer, and reducing the weld layer void rate. After the composite welded sheet has completely solidified, bolt 21 is unscrewed.Remove the elastic pressure plate 12 and the cover plate 18, then sequentially remove the liner fixing component 14 and the welding piece fixing component 10, finally obtaining a finished product with a reliable connection between the composite welding piece and the IGBT liner, completing the entire large-area welding process.

[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0022] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A composite tab based IGBT package large area soldering device comprising a base plate (1), characterized in that: The bottom plate (1) has an inlet (2) on one side of its outer wall and an outlet (7) on the other side of its outer wall. The bottom plate (1) has an inlet groove (3), a guide groove (4) and a spiral flow channel (5) inside it, and the spiral flow channel (5) is connected to the guide groove (4), the inlet groove (3) and the outlet groove (6).

2. The large area soldering device for IGBT package based on composite soldering sheet according to claim 1, characterized in that: The upper surface of the base plate (1) is provided with a gradient truncated cone (8).

3. The large area soldering device for IGBT package based on composite soldering sheet according to claim 2, characterized in that: Fixing pins (9) are provided at the four corners of the base plate (1), and welding sheet fixing parts (10) are provided on the upper surface of the base plate (1).

4. The large area soldering device for IGBT package based on composite soldering sheet according to claim 3, characterized in that: The welding sheet fixing component (10) has a first fixing ring (11) at the position corresponding to the fixing pin (9), a first through cavity (13) is provided inside the welding sheet fixing component (10), and a liner fixing component (14) is provided on the welding sheet fixing component (10).

5. The large area soldering device for IGBT package based on composite soldering sheet according to claim 4, characterized in that: The liner fastener (14) has a second through cavity (16), and the liner fastener (14) has a second fixing ring (15) at the position corresponding to the fixing pin (9).

6. The large area soldering device for IGBT package based on composite soldering sheet according to claim 5, characterized in that: The upper surface of the liner fastener (14) is provided with a first fixing hole (17), and the upper surface of the liner fastener (14) is provided with a cover plate (18). The cover plate (18) is provided with a third fixing ring (19) at the position corresponding to the fixing pin (9), and the cover plate (18) is provided with a second fixing hole (20) at the position corresponding to the first fixing hole (17).

7. The large area soldering device for IGBT package based on composite soldering sheet according to claim 6, characterized in that: Both the first fixing hole (17) and the second fixing hole (20) are threaded with bolts (21), and elastic pressure plates (12) are sleeved on the bolts (21).

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