Method for making a power module structure

Abstract

The application relates to a method for manufacturing a power module structure. The method comprises the following steps: providing a substrate made of a substrate material different from copper material, the substrate comprising at least one region; punching a plurality of holes corresponding to copper bar terminals of the power module structure in each region; fixing a copper plate to the substrate at the position of each hole; punching a frame structure in each region of the substrate; punching each copper plate to obtain a corresponding copper bar terminal; fixing a ceramic substrate to the plurality of copper bar terminals; injection molding the ceramic substrate; and cutting the frame structure to leave the plurality of copper bar terminals and the ceramic substrate. The method for manufacturing the power module structure improves the utilization rate of copper material, reduces the overall manufacturing cost of the power module structure, and improves product competitiveness.

Description

Technical Field

[0001] This invention relates to the field of inverter technology, and more particularly to the power module of an inverter, specifically to a method for manufacturing a power module structure. Background Technology

[0002] In electric vehicles, the inverter is a key component of the powertrain system. It not only converts direct current (DC) to alternating current (AC) to drive the motor, but also converts AC to DC during braking to charge the battery, thereby improving energy efficiency. The inverter is typically located within the motor controller and works in conjunction with it to ensure the vehicle's normal operation. It receives and processes the demand signals from the drive motor, adjusting the frequency to precisely control the motor's operation.

[0003] An inverter typically contains multiple half-bridge power modules. These power modules are composed of power electronic devices arranged in a specific functional combination and then packaged on a ceramic substrate. The power electronic devices are completely encapsulated within the ceramic substrate and connected to other electronic devices via multiple high- and low-voltage terminals extending out of the ceramic substrate. The high- and low-voltage terminals are typically made of copper busbars and formed by sheet metal stamping.

[0004] In existing technologies, the copper busbar terminals and / or signal terminals in power modules are typically punched from a single sheet of copper. The copper busbar terminals and / or signal terminals formed on this sheet often occupy only a small portion of the original copper sheet material. This results in low copper sheet utilization and consequently, higher overall manufacturing costs for the power module.

[0005] Therefore, there is a need to propose an improved method for manufacturing power module structures that can maximize the utilization of copper materials and reduce manufacturing costs. Summary of the Invention

[0006] In view of this, according to one aspect of the present invention, a method for manufacturing a power module structure is provided, the power module structure including a plurality of copper busbar terminals and a ceramic substrate, the method comprising the following steps: providing a substrate made of a substrate material different from copper, the substrate including at least one region, wherein each region corresponds to a power module structure; punching a plurality of holes in each region corresponding to the copper busbar terminals of the power module structure; fixing a copper plate to the substrate at the location of each punched hole; punching a frame structure in each region of the substrate, the frame structure carrying all the copper plates fixed to the substrate in that region; punching each copper plate to obtain a corresponding copper busbar terminal; providing a ceramic substrate and fixing it to the plurality of copper busbar terminals in the corresponding region; injection molding the ceramic substrate; and cutting the frame structure in each region to leave the plurality of copper busbar terminals and the ceramic substrate, ultimately obtaining a power module structure corresponding to that region.

[0007] According to one embodiment of the present invention, fixing a copper plate to the substrate at each punch location includes: embedding the copper plate into the corresponding punch in a form-fitting manner, and fixing the copper plate to the substrate.

[0008] According to one embodiment of the present invention, a copper plate is placed above the corresponding punch and the copper plate is fixed to the substrate, wherein the copper plate is sized such that at least a portion of the outer peripheral edge of the copper plate rests on the substrate material.

[0009] According to one embodiment of the present invention, the copper plate is fixed to the substrate by welding.

[0010] According to one embodiment of the present invention, the copper plate and the substrate are fixed by friction stir welding.

[0011] According to one embodiment of the present invention, the power module structure further includes a plurality of signal terminals; before the ceramic substrate is injection molded, the plurality of signal terminals extending perpendicularly to the surface of the ceramic substrate are fixed thereon.

[0012] According to one embodiment of the present invention, punching out a plurality of holes in each region corresponding to the copper busbar terminals of the power module structure includes: punching out a first hole in each region, wherein a first copper plate for punching out a first copper busbar terminal intended to be connected to a first end of the ceramic substrate is arranged in the first hole; and punching out a second hole in each region, wherein a second copper plate for punching out a second, third, and fourth copper busbar terminal intended to be connected to a second end of the ceramic substrate is arranged in the second hole.

[0013] According to one embodiment of the present invention, the power module structure further includes a plurality of signal terminals; the first copper plate is punched to obtain the plurality of signal terminals connected to the first end of the ceramic substrate.

[0014] According to one embodiment of the present invention, the substrate material is aluminum.

[0015] According to one embodiment of the present invention, the power module structure is used in an inverter.

[0016] Compared to existing technologies, the method of the present invention carries a copper plate on a substrate made of a substrate material that is different from copper and, for example, cheaper, and punches out the required copper busbar terminals and / or signal terminals from the copper plate, which can greatly improve the utilization rate of copper material and thus reduce the overall manufacturing cost of the power module structure. Attached Figure Description

[0017] The features and advantages of the present invention will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on the invention, wherein:

[0018] Figure 1 A perspective view is shown of a power module structure (including signal terminals) manufactured by a method according to an embodiment of the present invention.

[0019] Figure 2 A flowchart illustrating a method for fabricating a power module structure according to an embodiment of the present invention is shown, wherein the fabrication process of signal terminals is not involved in the flowchart.

[0020] Figure 3a The first embodiment is shown. Figure 2 The diagram shows a region on the substrate corresponding to a power module structure, where copper plates are embedded into corresponding punch holes in a shape-fitting manner.

[0021] Figure 3b Show Figure 3a The diagram shows the completed power module structure after the copper busbar terminals are fixed to the ceramic substrate.

[0022] Figure 4a The second embodiment is shown. Figure 2 A schematic diagram of one region of a power module structure on a substrate, wherein the copper plate is sized such that its outer peripheral edge rests on the substrate material.

[0023] Figure 4b Show Figure 4a The diagram shows the completed power module structure after the copper busbar terminals are fixed to the ceramic substrate.

[0024] Figure 5 This illustrates a schematic process of forming multiple copper busbar terminals and signal terminals using a copper plate supported by a substrate.

[0025] Figure 6 Show Figure 5 The diagram shows the product after the power module structure is fixed to the ceramic substrate. Detailed Implementation

[0026] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the invention. However, it will be apparent to those skilled in the art that implementation of the invention may not include some of these specific details. Furthermore, it should be understood that the invention is not limited to the specific embodiments described. Rather, the invention can be conceived to be practiced with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0027] The terms "first" and "second" are used below to describe the elements of this application. These terms are used only to distinguish the individual elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusion and mean that there may be additional elements / components besides those listed.

[0028] Figure 1 A final product diagram of a power module structure 1 manufactured according to an embodiment of the present invention is shown. Figure 1 As shown, the power module structure 1 may include multiple copper busbar terminals 11 and a ceramic substrate 12 (see Figure 1). Figure 2 As shown in Figure d), the plurality of copper busbar terminals 11 are arranged at intervals. This power module structure 1 can be configured as a half-bridge power module for an inverter. For example, a copper busbar terminal 11 (i.e., the first copper busbar terminal) is provided at the first end of the power module structure 1, while three copper busbar terminals 11 (i.e., the second, third, and fourth copper busbar terminals) are arranged side-by-side and at intervals at the second end of the power module structure 1 opposite to the first end. In practical applications, three power module structures 1 can be set, where the first copper busbar terminals of the three power module structures correspond to the respective phases of the AC power (U, V, W phases), and the second, third, and fourth copper busbar terminals correspond to the positive and negative terminals, respectively. Of course, depending on the power requirements, more power module structures can be set, for example, six power module structures can be set, where every two power module structures are connected in parallel.

[0029] See also Figure 1 The diagram also shows that the power module structure 1 may include a plurality of signal terminals 14, which may, for example, be located on the same side as the first copper busbar terminal. Of course, the signal terminals can also be formed in other ways, for example, they may extend perpendicularly to the surface of the ceramic substrate. The ceramic substrate 12 is fixed to each copper busbar terminal 11, and optionally an injection-molded layer 13 is formed on the outer periphery of the ceramic substrate 12.

[0030] Figure 2 A method for manufacturing a power module structure is illustrated. To facilitate explanation of the method of the present invention, the process of manufacturing the signal terminal 14 of the power module structure 1 is omitted in the flowchart of this embodiment, but this is not intended to limit the method to excluding the manufacturing of the signal terminal. Next, reference will be made to... Figure 2 The present invention describes in detail the method for manufacturing a power module structure.

[0031] exist Figure 2 Figure a shows a substrate 2 made of a substrate material. The material of substrate 2 can be different from copper, especially a material that is cheaper than copper, such as aluminum. Thus, in manufacturing the power module structure 1, the substrate 2, for example made of aluminum, supports and fixes the copper plate 3 made of copper, and the excess copper plate material and substrate material are discarded after multiple copper busbar terminals 11 are cut from the copper plate 3. Since the amount of discarded copper material is greatly reduced, the utilization rate of copper material is improved, and the manufacturing cost is greatly reduced. At least one region 21 can be divided on the substrate 2, and each region 21 corresponds to one power module structure 1. The number of regions 21 depends on the raw material size of the substrate. For example, Figure 2 The substrate 2 is shown to be large enough to accommodate six regions 21, each corresponding to one of the six power module structures 1.

[0032] Additionally, in Figure a, multiple punch holes 22 are cut out in each region 21 to correspond to the copper busbar terminals 11 of the power module structure 1. For example, compared to... Figure 1In the power module structure 1 shown, the plurality of punches 22 may include first punches and second punches respectively disposed at opposite first and second ends of each region 21. For example, there may be one first punch, which corresponds to a copper bus terminal 11 (i.e., a first copper bus terminal) at the first end of the ceramic substrate 12, thereby allowing a first copper plate corresponding to the first copper bus terminal to be arranged in the first punch; there may also be one second punch, which corresponds to three copper bus terminals 11 (i.e., a second copper bus terminal, a third copper bus terminal, and a fourth copper bus terminal) at the second end of the ceramic substrate 12, thereby allowing a second copper plate corresponding to the second, third, and fourth copper bus terminals to be arranged in the second punch. In embodiments where the power module structure 1 is larger overall, there may also be multiple punches 22 located at the second end, each punch 22 corresponding to a copper bus terminal 11.

[0033] Figure 2 Figure b shows multiple copper plates 3 fixed to the substrate 2 at corresponding punched holes 22. The fixing method can be various welding methods or other fixing methods known in the art, which facilitates the fixing of the copper plates 3 through the substrate 2 and punching out the copper busbar terminals 11 from the corresponding copper plates 3.

[0034] Then, a frame structure 4 is punched out in each region of the substrate 2, such as the frame structure 4 corresponding to one region 21. Figure 2 As shown in Figure c, the frame structure 4 may include a frame-shaped portion formed around the periphery of each region 21 by a punched substrate 2 and ribs extending inward from the inner periphery of the frame-shaped portion to each copper plate 3, thereby enabling all the copper plates 3 in the region 21 to be supported together by the ribs and the frame-shaped portion. For example, two pairs of ribs are formed side by side at the first end of the frame-shaped portion corresponding to the region 21, each pair of ribs being on both sides of the corresponding copper plate 3 and fixed to the copper plate 3. A pair of ribs are formed side by side at the second end of the frame-shaped portion corresponding to the region 21, this pair of ribs being on both sides of the corresponding copper plate 3 and fixed to the copper plate 3.

[0035] Figure 2 Figure c also shows that punching each copper plate 3 yields one or more corresponding copper busbar terminals 11. Since the original copper plate 3 is larger than the final copper busbar terminal 11, after punching, the copper busbar terminal 11 forms one or more legs at its location adjacent to the ribs or frame-shaped portions of the frame structure to connect with the corresponding ribs or frame-shaped portions. For example, located at the first end corresponding to region 21 ( Figure 2 The copper busbar terminal 11 (shown in Figure c, upper end) has two legs on its left, right, and upper sides respectively, which are connected to the rib or frame portion. The second end located in region 21 ( Figure 2Of the three copper busbar terminals 11 shown in Figure c (at the lower end), the left and right copper busbar terminals 11 each have legs connected to ribs or frame-shaped portions. The middle copper busbar terminal, being adjacent to the left and right copper busbar terminals 11 and the lower frame-shaped portion, has ribs formed between it and the left and right copper busbar terminals 11 through punching the copper plate 3. Furthermore, the lower end of this copper busbar terminal 11 also has legs connected to the lower frame-shaped portion. In this figure, the lower legs of the three copper busbar terminals 11 also have connecting portions formed on the frame-shaped portion. It is understood that punching the frame structure 4 and punching the copper busbar terminals 11 on the substrate 3 can be done simultaneously in one punching operation, or it can be done through multiple punching operations. Furthermore, the hollowed-out portion in the middle of the frame-shaped portion can serve as a mounting position for the ceramic substrate 12. It should be understood that the frame structure 4 can also be fixed to a fixture on the production line for positioning functions, etc.

[0036] Continue to refer to Figure 2 As shown in Figure d, the ceramic substrate 12 is mounted to the hollowed-out portion in the middle of the frame structure 4 and is fixedly connected to multiple copper busbar terminals within the frame structure 4. For example, the ceramic substrate 12 can be formed by laminating multiple substrate layers, so the frame structure 4 can be fixed via a positioning structure during the lamination process, thereby fixing the multiple copper busbar terminals 11.

[0037] refer to Figure 2 As shown in Figure e, the ceramic substrate 12 and copper bus terminals 11 are both fixed to the frame structure 4, and an injection molding layer 13 is formed on the surface of the ceramic substrate 12 by injection molding (generally using epoxy resin), thereby encapsulating the power module structure 1. Then, the frame structure 4 in each region 21 is cut to remove excess parts, such as the frame-shaped portion of the frame structure 4, ribs, the legs of each copper bus terminal 11, and the ribs between adjacent copper bus terminals 11, leaving the ceramic substrate 12 and multiple copper bus terminals 11 connected to the ceramic substrate 12, ultimately obtaining the power module structure 1 corresponding to that region 21, as shown below. Figure 2 As shown in Figure f.

[0038] against Figure 2 As shown in Figure b, fixing a copper plate 3 to the substrate 2 at each punch 22 position may include: embedding the copper plate 3 into the corresponding punch 22 in a form-fit manner, and fixing the copper plate 3 to the substrate 2, wherein the outer shape of the copper plate is complementary to the shape of the corresponding punch. In this case, the copper plate 3 and the substrate 2 may be fixed by welding or by other fixing methods known in the art. Figure 3a and 3bThe diagram shows a copper busbar terminal 11 formed by joining copper plates and substrates together in a shape-fitting manner and then punching them together, wherein the legs of the copper busbar terminal are flush with the ribs and frame-shaped portions of the corresponding frame structure 4.

[0039] and Figure 3a and 3b The illustrated embodiment differs from the one shown in that, Figure 4a and Figure 4b A frame structure 4 formed according to another embodiment is shown. In this embodiment, fixing a copper plate 3 to the substrate 2 at each punch 22 location may include: placing the copper plate 3 above the corresponding punch 22 and fixing the copper plate 3 to the substrate 2, wherein the copper plate is sized such that at least a portion of its outer peripheral edge rests on the substrate material. Figure 4a As shown, the perforation 22 is roughly rectangular, and the copper plate 3 is also rectangular with the same shape as the perforation 22. The length and width of the copper plate 3 are slightly larger than those of the perforation 22, so that when the copper plate 3 is placed above the corresponding perforation 22 and their centers are aligned, the entire outer periphery of the copper plate rests on the substrate material. Thus, the copper plate 3 and the substrate 2 can be fixed in the overlapping area by welding, such as friction stir welding. Of course, other methods can also be used to fix the copper plate 3 and the substrate 2 in the overlapping area, such as ultrasonic welding. Figure 4b The diagram shows a copper busbar terminal 11 formed by fixing copper plates and substrates in an up-and-down stacking manner and punching, wherein the support legs of the copper busbar terminal are joined to the ribs and frame-shaped parts of the corresponding frame structure 4 in an up-and-down overlapping manner.

[0040] Figure 5 and Figure 6 The production process was shown. Figure 1 The process product diagram of power module structure 1 shown is shown. Figure 5 The left figure shows one of the regions 21 punched out from the substrate 2. Combined with... Figure 5 As shown in the left and right figures, in region 21, the two punches 22 located at the first and second ends of region 21 are both approximately rectangular and aligned in length. A copper plate 3 is connected to the punch 22 at the upper first end in a form-fit manner. This copper plate can be punched to form multiple signal terminals 14 and a copper busbar terminal 11, etc. Another copper plate 3 is also connected to the punch 22 at the lower second end in a form-fit manner. This copper plate can be punched to form three copper busbar terminals 11. Then, the frame structure 4 can be punched to remove excess frame-shaped parts, legs, ribs, etc., and the signal terminals 14 and copper busbar terminals 11 can be punched and bent to form... Figure 1 The power module structure shown is 1.

[0041] Optionally, Figure 6The diagram shows a product after the copper plate 3 is fixed above the punch 22 in region 21 by stacking copper plates and then punched to form copper busbar terminals and signal terminals, and finally fixed to the ceramic substrate 12.

[0042] Of course, the order of the above steps is not strictly limited. For example, after cutting off the excess part of the frame structure 4, corresponding bending operations can be performed on the copper busbar terminals 13 and signal terminals 14, such as... Figure 6 As shown. This bending operation can also be performed before cutting or before forming the injection layer 13.

[0043] As described above, compared with the prior art, the method of the present invention carries a copper plate on a substrate made of a relatively inexpensive substrate material that is different from copper, and punches out the required copper busbar terminals and / or signal terminals from the copper plate, which can greatly improve the utilization rate of copper material, reduce the overall manufacturing cost of the power module structure, and improve product competitiveness.

[0044] Various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art based on the practice of the invention disclosed in this specification. This specification and the examples disclosed herein should be considered illustrative only, and the true scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for fabricating a power module structure, the power module structure comprising a plurality of copper busbar terminals and a ceramic substrate, characterized in that, The method includes the following steps: A substrate is provided made of a substrate material different from copper, the substrate including at least one region, wherein each region corresponds to a power module structure; Multiple punches corresponding to the copper busbar terminals of the power module structure are punched out in each region; At each punching location, a copper plate is fixed to the substrate; A frame structure is punched out in each region of the substrate, and the frame structure carries all the copper plates fixed to the substrate in that region; Each copper plate is punched to obtain the corresponding copper busbar terminal; A ceramic substrate is provided and fixedly connected to the plurality of copper busbar terminals in the corresponding areas; The ceramic substrate is injection molded and encapsulated; and The frame structure in each region is cut to leave the multiple copper busbar terminals and the ceramic substrate, thus obtaining the power module structure corresponding to that region.

2. The method according to claim 1, characterized in that, Fixing a copper plate to the substrate at each punch location includes: The copper plate is embedded into the corresponding punch hole in a shape-fitting manner, and the copper plate is fixed to the substrate.

3. The method according to claim 1, characterized in that, Fixing a copper plate to the substrate at each punch location includes: A copper plate is placed above the corresponding punch and fixed to the substrate, wherein the copper plate is sized such that at least a portion of its outer peripheral edge rests on the substrate material.

4. The method according to claim 2 or 3, characterized in that, The copper plate is fixed to the substrate by welding.

5. The method according to claim 4, characterized in that, The copper plate is fixed to the substrate by friction stir welding.

6. The method according to any one of claims 1 to 3, characterized in that, The power module structure also includes multiple signal terminals; before the ceramic substrate is injection molded, the multiple signal terminals, which extend perpendicularly to the surface of the ceramic substrate, are fixed on the surface of the ceramic substrate.

7. The method according to any one of claims 1 to 3, characterized in that, Punching multiple holes in each region corresponding to the copper busbar terminals of the power module structure includes: A first punch is cut out in each region, wherein a first copper plate is arranged in the first punch for cutting out a first copper bus terminal intended to be connected to a first end of a ceramic substrate; A second punch is cut out in each region, wherein a second copper plate is arranged in the second punch for punching out second, third and fourth copper bus terminals intended to be connected to the second end of the ceramic substrate.

8. The method according to claim 7, characterized in that, The power module structure also includes multiple signal terminals; the first copper plate is punched to obtain the multiple signal terminals that are connected to the first end of the ceramic substrate.

9. The method according to any one of claims 1 to 3, characterized in that, The substrate material is aluminum.

10. The method according to any one of claims 1 to 3, characterized in that, The power module structure is used in inverters.

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