power module
By designing an asymmetric encapsulation structure for the power terminals in the power module, the heat generation problem caused by the increased exposed area is solved, the power density is improved and the cost is reduced, while ensuring current carrying capacity and connection reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUZHOU INOSA UNITED POWER SYST CO LTD
- Filing Date
- 2025-07-11
- Publication Date
- 2026-06-26
AI Technical Summary
When increasing the output current, existing power modules increase the exposed area, leading to excessive current density and severe heat generation. Furthermore, the existing structure cannot effectively improve power density and reduce costs.
Design a power module structure in which the plastic package covers the first side of the power terminal with a length greater than the second side, and part of the second side is exposed. Combine the substrate, chip assembly and plastic package to avoid increasing the volume of the substrate and plastic package, and use laser welding to connect the external circuit.
This improves the power density of the power module, reduces costs, avoids the increase of stray inductance, and ensures the efficiency of the power module and its current carrying capacity during self-testing.
Smart Images
Figure CN224419280U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power electronics technology, and in particular to a power module. Background Technology
[0002] With the rapid development of power electronics technology, power modules, as core components for power conversion, are widely used in new energy power generation, electric vehicles, industrial frequency conversion, and other fields. Power modules typically include power semiconductor chips (such as IGBTs, SiC MOSFETs, etc.), substrates, plastic packages, and power terminals.
[0003] For a power module, the exposed area of the power terminals is fixed under the same output current. Understandably, as the output current increases, the exposed area also increases; otherwise, excessive current density and severe heat generation would occur.
[0004] For structures where power terminals are fully embedded in the molding compound, increasing the exposed area of the power terminals requires increasing the volume of the substrate and the molding compound, which in turn increases the volume of the power module and reduces the power density. Utility Model Content
[0005] The main objective of this invention is to propose a power module that aims to improve the power density of the power module.
[0006] To achieve the above objectives, the power module proposed in this utility model includes:
[0007] substrate;
[0008] A chip assembly is mounted on the substrate and electrically connected to the substrate.
[0009] A power terminal, electrically connected to the substrate, and electrically connected to the chip assembly via the substrate; and
[0010] A molding compound that encapsulates the substrate, the chip assembly, and a portion of the power terminals;
[0011] Wherein, along the thickness direction of the power terminal, the power terminal has a first side and a second side opposite to each other, and the encapsulation length covering the first side is greater than the encapsulation length covering the second side.
[0012] In one embodiment, along the length of the power terminal, the power terminal includes a first segment and a second segment connected to each other, the first segment being connected to the molding compound, and both the first side and the second side of the second segment being exposed from the molding compound.
[0013] In one embodiment, the second segment is located on the same plane as the first segment; or, the second segment is bent relative to the first segment.
[0014] In one embodiment, the width of the second segment is smaller than the width of the first segment along the width direction of the power terminal.
[0015] In one embodiment, the area of the second segment is smaller than the area of the first segment.
[0016] In one embodiment, the power terminal includes a plurality of conductive portions, and at least one of the conductive portions is provided with a positioning hole.
[0017] In one embodiment, when the areas of the multiple conductive portions are the same, the positioning hole is provided on any one of the conductive portions; when the areas of the multiple conductive portions are different, the positioning hole is provided on the conductive portion with the largest area.
[0018] In one embodiment, on the second side, the molding compound has spacer ribs formed between adjacent conductive portions.
[0019] In one embodiment, the power module further includes a metal boss and a signal terminal. The metal boss is mounted on the substrate and electrically connected to the substrate, and is disposed adjacent to the chip assembly. The molding compound covers part of the metal boss, and the molding compound has mounting holes corresponding to the metal boss. The signal terminal passes through the mounting holes and is electrically connected to the metal boss.
[0020] In one embodiment, the power module further includes a heat sink, and the molding compound is connected to the heat sink.
[0021] The technical solution of this utility model involves setting a substrate, chip assembly, power terminals, and a molding compound in a power module. The chip assembly is mounted on the substrate and electrically connected to the substrate. The power terminals are electrically connected to the substrate and, through the substrate, to the chip assembly. The molding compound covers the substrate, chip assembly, and a portion of the power terminals. Along the thickness direction of the power terminals, the power terminals have opposing first and second sides. The covering length of the molding compound on the first side is greater than the covering length on the second side. Thus, compared to the fully embedded power modules of the prior art, this utility model, by making the covering length of the molding compound on the first side greater than the covering length on the second side, exposes at least a portion of the second side, thereby increasing the exposed area of the power terminals. This avoids increasing the volume of the substrate and molding compound, and thus avoids increasing the volume of the power module, which is beneficial for improving the power density of the power module and also helps to reduce the cost of the power module. Attached Figure Description
[0022] 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 only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0023] Figure 1 This is a partial structural schematic diagram of an embodiment of the power module provided by this utility model.
[0024] Explanation of icon numbers:
[0025] 100. Power terminal; 111. First side; 112. Second side; 121. First section; 122. Second section; 130. Conductive portion; 131. Positioning hole;
[0026] 200. Plastic sealant; 210. Spacer rib; 220. Mounting hole;
[0027] 300. Self-test probe.
[0028] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.
[0030] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.
[0031] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.
[0032] With the rapid development of power electronics technology, power modules, as core components for power conversion, are widely used in new energy power generation, electric vehicles, industrial frequency conversion, and other fields. Power modules typically include power semiconductor chips (such as IGBTs, SiC MOSFETs, etc.), substrates, plastic packages, and power terminals.
[0033] For a power module, the exposed area of the power terminals is fixed under the same output current. Understandably, as the output current increases, the exposed area also increases; otherwise, excessive current density and severe heat generation would occur.
[0034] For structures where power terminals are fully embedded in the molding compound, increasing the exposed area of the power terminals requires increasing the volume of the substrate and the molding compound, which increases the volume of the power module, reduces the power density, and increases the cost.
[0035] For structures where the power terminals extend entirely from the molded enclosure, the power terminals need to be extended in length and area. Understandably, the portion of the power terminals extending from the enclosure lacks support, making laser welding an unsuitable method for connecting them to external circuits. The power terminals must be extended lengthwise and then bent upwards to connect to external circuits using a stacked welding method. This further increases the length and area of the power terminals, reduces the power density of the power module, increases the number of power terminals used, and increases cost. Simultaneously, it increases stray inductance on the input side, reduces the switching efficiency of the power module, and also reduces the power density. Therefore, neither of these two structural forms effectively resolves the contradiction between increasing power density and miniaturization in power modules.
[0036] This utility model proposes a power module.
[0037] Please see Figure 1In one embodiment of the present invention, the power module includes a substrate (not shown), a chip assembly (not shown), a power terminal 100, and a molding compound 200. The chip assembly is mounted on the substrate and electrically connected to the substrate. The power terminal 100 is electrically connected to the substrate and electrically connected to the chip assembly through the substrate. The molding compound 200 covers the substrate, the chip assembly, and a portion of the power terminal 100. Along the thickness direction of the power terminal 100, the power terminal 100 has a first side 111 and a second side 112, and the covering length of the molding compound 200 on the first side 111 is greater than the covering length on the second side 112.
[0038] Understandably, the power terminal 100 has a certain length, width, and thickness (e.g., Figure 1 As shown in the figure, the thickness direction of the power terminal 100 is also the thickness direction of the power module, and the length direction of the power terminal 100 is also the direction in which the power terminal 100 extends out of the molding compound 200.
[0039] Along the thickness direction of the power terminal 100, the power terminal 100 has opposing first sides 111 and second sides 112; along the length direction of the power terminal 100, the covering length of the molding compound 200 over the first side 111 is greater than the covering length over the second side 112. For ease of explanation, along the length direction of the power terminal 100, the power terminal 100 is defined as having a connected front portion and a rear portion, wherein the rear portion is closer to the edge of the molding compound 200. When the molding compound 200 covers the first side 111 and the second side 112, the covering is always from the front portion to the rear portion. That is, in the power module, the molding compound 200 extends continuously, rather than being segmented.
[0040] Understandably, along the length of the power terminal 100, the molding compound 200 partially or completely covers the first side 111, while the molding compound 200 does not cover or partially covers the second part. This results in the second side 112 of the power terminal 100 having a larger exposed area compared to the first side 111, thereby increasing the exposed surface area of the power terminal 100 and reducing problems such as local heating and local arcing caused by insufficient current flow area at the power connection position.
[0041] Compared to a fully embedded structure, the semi-embedded structure in this invention does not increase the volume of the substrate and the molding compound 200, and thus does not increase the volume of the power module, avoiding stray inductance and ensuring the power density and efficiency of the power module; at the same time, it does not increase the cost of the power module.
[0042] Compared to a fully extended structure, the semi-recessed structure of this invention means that at least a portion of the second side 112 of the power terminal 100 is not covered by the plastic sealant 200, while the corresponding first side 111 is covered by the plastic sealant 200. That is, at this location, the first side 111 is covered by the plastic sealant 200, while the second side 112 is exposed. In other words, at this location, the plastic sealant 200 of the first side 111 provides support for the power terminal 100 on the second side 112. In this case, the power terminal 100 can be connected to an external circuit via laser welding, thus avoiding the need for additional lengthening and bending of the power terminal 100 due to the limitation of only using interlocking welding. This prevents the power terminal 100 from becoming excessively long, thereby avoiding an increase in stray inductance and ensuring the power density and efficiency of the power module.
[0043] Understandably, in one embodiment, the power terminal 100 is configured as a copper busbar. Of course, in other embodiments, the power terminal 100 can also be made of aluminum busbar, copper alloy, aluminum alloy, etc. No limitation is placed on the material of the power terminal 100 here.
[0044] The technical solution of this utility model involves setting a substrate, a chip assembly, power terminals 100, and a molding compound 200 in a power module. The chip assembly is mounted on the substrate and electrically connected to the substrate. The power terminals 100 are electrically connected to the substrate and, through the substrate, electrically connected to the chip assembly. The molding compound 200 covers the substrate, the chip assembly, and a portion of the power terminals 100. Along the thickness direction of the power terminals 100, the power terminals 100 have opposing first sides 111 and second sides 112. The covering length of the molding compound 200 on the first side 111 is greater than the covering length on the second side 112. Thus, compared to the fully embedded power modules in the prior art, this utility model, by making the covering length of the molding compound 200 on the first side 111 greater than the covering length on the second side 112, exposes at least a portion of the second side 112, thereby increasing the exposed area of the power terminals 100. This avoids increasing the volume of the substrate and the molding compound 200, and thus avoids increasing the volume of the power module, which is beneficial for improving the power density of the power module and reducing its cost.
[0045] In an embodiment of the present invention, along the length direction of the power terminal 100, the power terminal 100 includes a first segment 121 and a second segment 122 connected to each other. The first segment 121 is connected to the molding compound 200, and the first side 111 and the second side 112 of the second segment 122 are both exposed from the molding compound 200.
[0046] Understandably, after the power module leaves the factory, users can connect it to external circuits by laser soldering the uncovered second side 112 during assembly. However, the power module needs to undergo self-testing before leaving the factory. Self-testing is generally performed by electrically connecting the self-test harness 300 to the exposed portion of the power terminal 100. Generally, the area required for laser soldering is significantly smaller than the area required for connecting the self-test harness 300. To ensure sufficient connection area for the self-test harness 300 during power module self-testing, in one embodiment, a second segment 122 is provided in the power terminal 100.
[0047] Specifically, along the length of the power terminal 100, the power terminal 100 includes a first segment 121 and a second segment 122 connected to each other. The first segment 121 is connected to the molding compound 200, meaning the length of the molding compound 200 covering the first side 111 of the first segment 121 is greater than the length of the molding compound 200 covering the second side 112 of the first segment 121. In one embodiment, the molding compound 200 fully covers the first side 111 of the first segment 121 and partially or not at all covers the second side 112 of the first segment 121. Both the first side 111 and the second side 112 of the second segment 122 are exposed from the molding compound 200. That is, neither the first side 111 nor the second side 112 of the second segment 122 is covered by the molding compound 200.
[0048] Thus, during self-testing, the self-test harness 300 can be electrically connected not only to the portion of the first segment 121 not covered by the plastic sealant 200 on the second side 112, but also to the second side 112 of the second segment 122. The second segment 122 increases the high current carrying capacity of the power terminal 100, thereby solving the defect that the surface area of the power terminal 100 is insufficient to carry high current during power module self-testing, and resolving the problem of surface arcing and burning of the power terminal 100 during self-testing.
[0049] In embodiments of this utility model, the second segment 122 and the first segment 121 are located on the same plane; or, the second segment 122 is bent relative to the first segment 121.
[0050] Specifically, in one embodiment, the second segment 122 and the first segment 121 are located on the same plane, that is, the second segment 122 and the first segment 121 extend in the same direction, which facilitates the placement of the self-test harness 300. In another embodiment, the second segment 122 is bent relative to the first segment 121, that is, the first segment 121 and the second segment 122 are set at an angle. Here, there is no restriction on the bending direction of the second segment 122 relative to the first segment 121, nor is there any restriction on the angle between the second segment 122 and the first segment 121, as long as the self-test harness 300 can be placed.
[0051] In an embodiment of this utility model, along the width direction of the power terminal 100, the width of the second segment 122 is smaller than the width of the first segment 121.
[0052] Understandably, once the power module completes its self-test and leaves the factory, when using the power module, the user only needs to laser solder the portion of the second side 112 of the first segment 121 that is not covered by the plastic encapsulation 200 when making electrical connections between the power terminal 100 and the external circuit; the second segment 122 is not required. In one embodiment, the width of the second segment 122 is set to be smaller than the width of the first segment 121, thus allowing the user to easily remove the second segment 122 according to their needs.
[0053] In an embodiment of this utility model, the area of the second segment 122 is smaller than the area of the first segment 121. By setting the area of the second segment 122 to be smaller than that of the first segment 121, on the one hand, the placement area of the self-test harness 300 during power module self-testing is ensured; on the other hand, excessive extension of the power terminal 100 is avoided, thereby preventing an increase in stray inductance. This is beneficial for improving the power density and efficiency of the power module and for reducing the cost of the power module.
[0054] In an embodiment of this utility model, the power terminal 100 includes a plurality of conductive portions 130, and at least one conductive portion 130 is provided with a positioning hole 131.
[0055] Understandably, in one embodiment, power terminal 100 refers to the terminal on the PN side of the power module. The PN-side power terminal 100 includes multiple conductive portions 130, the number of which may be two or three, and is not limited here. Understandably, the power module also includes a heat sink (not shown), which is connected to the molding compound 200. The substrate, chip assembly, power terminal 100, and molding compound 200, after being encapsulated, are defined as a plastic-encapsulated whole. To facilitate alignment and connection between the plastic-encapsulated whole and the heat sink, at least one conductive portion 130 is provided with a positioning hole 131. This improves the accuracy and speed of connection between the plastic-encapsulated whole and the heat sink. Understandably, the positioning hole 131 is located in the second segment 122, that is, the positioning hole 131 is exposed from the molding compound 200 to facilitate alignment between the positioning hole 131 and the heat sink. The positioning hole 131 can be circular, elliptical, etc., and its shape is not limited here. In the embodiment shown in the figures of this utility model, a positioning hole 131 is provided on one conductive portion 130. Of course, in other embodiments, positioning holes 131 may be provided on two or three conductive portions 130, which is not limited here.
[0056] In the embodiments of this utility model, when the areas of the multiple conductive portions 130 are the same, the positioning hole 131 is provided on any conductive portion 130; when the areas of the multiple conductive portions 130 are different, the positioning hole 131 is provided on the conductive portion 130 with the largest area.
[0057] Understandably, the larger the area of the conductive portion 130, the greater its structural strength; the placement of the positioning hole 131 affects the structural strength of the conductive portion 130. When multiple conductive portions 130 have the same area, the positioning hole 131 can be placed on any one of the conductive portions 130. When multiple conductive portions 130 have different areas, the positioning hole 131 is placed on the conductive portion 130 with the largest area, thereby avoiding a further reduction in structural strength if the positioning hole 131 is placed on the conductive portion 130 with a smaller area.
[0058] In an embodiment of the present invention, on the second side 112, the molding compound 200 has a spacer 210 formed between adjacent conductive portions 130.
[0059] Specifically, on the second side 112, the molding compound 200 has a spacer 210 between adjacent conductive portions 130. The spacer 210 extends along the length of the power terminal 100, and the spacer is located in the first segment 121. Thus, the spacer 210 increases the creepage distance between adjacent conductive portions 130, thereby improving the safety of the power module. In one embodiment, the length of the spacer 210 is equal to the length of the first segment 121 to ensure the increased creepage distance. The width of the spacer 210 is not limited here.
[0060] In an embodiment of this invention, the power module further includes a metal boss (not shown) and a signal terminal (not shown). The metal boss is mounted on and electrically connected to the substrate, and is disposed adjacent to the chip assembly. A molding compound 200 covers a portion of the metal boss, and the molding compound 200 has mounting holes 220 corresponding to the metal boss. The signal terminal passes through the mounting holes 220 and is electrically connected to the metal boss. Thus, the signal terminal is led out from the mounting holes 220 on one side surface of the molding compound 200, and the signal terminal forms an electrical connection with the chip assembly through the metal boss and the substrate. This brings the signal terminal closer to the chip assembly, effectively reducing noise and improving the stability of the circuit current.
[0061] In an embodiment of this utility model, the power module further includes a heat sink, and the molding compound 200 is connected to the heat sink.
[0062] Understandably, the power module generates heat during operation. To avoid the impact of excessive temperature on the power module, in one embodiment, the power module further includes a heat sink. The side of the molding compound 200 facing away from the mounting hole 220 is connected to the heat sink, specifically by welding or hinge.
[0063] The above description is merely an exemplary embodiment of the present utility model and does not limit the scope of protection of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present utility model.
Claims
1. A power module, characterized in that, include: substrate; A chip assembly is mounted on the substrate and electrically connected to the substrate. The power terminal is electrically connected to the substrate and, through the substrate, is electrically connected to the chip assembly. as well as A molding compound that encapsulates the substrate, the chip assembly, and a portion of the power terminals; Wherein, along the thickness direction of the power terminal, the power terminal has a first side and a second side opposite to each other, and the encapsulation length covering the first side is greater than the encapsulation length covering the second side.
2. The power module as described in claim 1, characterized in that, Along the length of the power terminal, the power terminal includes a first segment and a second segment connected to each other, the first segment being connected to the molding compound, and the first side and the second side of the second segment both protruding from the molding compound.
3. The power module as described in claim 2, characterized in that, The second segment is located on the same plane as the first segment; or, the second segment is bent relative to the first segment.
4. The power module as described in claim 2, characterized in that, Along the width direction of the power terminal, the width of the second segment is smaller than the width of the first segment.
5. The power module as described in claim 2, characterized in that, The area of the second segment is smaller than the area of the first segment.
6. The power module as described in claim 1, characterized in that, The power terminal includes multiple conductive portions, and at least one of the conductive portions is provided with a positioning hole.
7. The power module as described in claim 6, characterized in that, When the areas of the multiple conductive portions are the same, the positioning hole is provided on any one of the conductive portions; when the areas of the multiple conductive portions are different, the positioning hole is provided on the conductive portion with the largest area.
8. The power module as described in claim 6, characterized in that, On the second side, the molding compound has spacer ribs formed between adjacent conductive portions.
9. The power module as described in claim 1, characterized in that, The power module further includes a metal boss and a signal terminal. The metal boss is mounted on the substrate and electrically connected to the substrate, and is disposed adjacent to the chip assembly. The molding compound covers part of the metal boss, and the molding compound has mounting holes corresponding to the metal boss. The signal terminal passes through the mounting holes and is electrically connected to the metal boss.
10. The power module as described in claim 1, characterized in that, The power module also includes a heat sink, and the molding compound is connected to the heat sink.