power module

Abstract

This utility model discloses a power module, relating to the field of power electronics technology. The power module includes a substrate, a chip assembly, power terminals, and a molding compound. The chip assembly is mounted on 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, the chip assembly, and a portion of the power terminals. The portion of the power terminals exposed within the molding compound has a through-hole structure. The technical solution provided by this utility model avoids cracking of the power module and improves its reliability.

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] When power modules are connected to electrical equipment or structures, such as motors, the power terminals are subjected to connection forces during the connection process, which may transmit stress to the molding compound. Under stress, the molding compound may be at risk of delamination or cracking. Utility Model Content

[0004] The main purpose of this invention is to provide a power module that avoids cracking of the plastic encapsulation and improves the reliability of the power module.

[0005] To achieve the above objectives, the power module proposed in this utility model includes:

[0006] substrate;

[0007] A chip assembly is mounted on the substrate and electrically connected to the substrate.

[0008] A power terminal, electrically connected to the substrate, and electrically connected to the chip assembly via the substrate; and

[0009] A molding compound that encapsulates the substrate, the chip assembly, and a portion of the power terminals;

[0010] The portion of the power terminal exposed outside the molding compound has a through-hole structure.

[0011] In one embodiment, the portion of the power terminal exposed outside the molding compound includes a first segment and a second segment connected together, the first segment being located on the side of the second segment closer to the molding compound, and the through-hole structure being provided in the first segment.

[0012] In one embodiment, the width of the first segment is greater than the width of the second segment.

[0013] In one embodiment, along the width direction of the power terminal, the first segment includes a main body and two lugs disposed on opposite sides of the main body, and along the length direction of the power terminal, the projection of the second segment overlaps with the main body.

[0014] The through-hole structure includes two first through holes arranged at intervals, the two first through holes being respectively disposed on the two lug portions and extending to the main body portion.

[0015] In one embodiment, the sum of the width of the second segment and the width of the through-hole structure is equal to the width of the first segment.

[0016] In one embodiment, the distance between the through-hole structure and the molding compound along the length direction of the power terminal is 0.5mm-1.5mm.

[0017] In one embodiment, the power terminal has a central axis extending along the length direction of the power terminal, and the through-hole structure is symmetrically arranged about the central axis.

[0018] In one embodiment, the through-hole structure is configured as a rectangular hole, a circular hole, or an irregularly shaped hole.

[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 within a power module. The chip assembly is mounted on 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. The portion of the power terminals exposed within the molding compound has a through-hole structure. This through-hole structure serves two purposes: First, when the power terminals are connected to electrical equipment or structures, the stress on the power terminals is absorbed by the through-hole structure, preventing external forces from being transmitted to the inside of the molding compound and causing cracking. This avoids cracking of the molding compound, improves the service life and reliability of the power module. Second, compared to the prior art, which extends the portion of the power terminals exposed within the molding compound, this avoids increasing the size of the power module, which is beneficial for increasing the power density. Simultaneously, it avoids the increased stray inductance from excessively long power terminals, preventing the reduction in switching efficiency caused by stray inductance, and thus avoiding a decrease in the power density of the power module. In addition, the portion of the power terminals exposed outside the plastic package does not require additional extension, thus ensuring current carrying capacity. 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 A partial structural schematic diagram of an embodiment of the power terminal provided by this utility model.

[0024] Explanation of icon numbers:

[0025] 100. Power terminal; 110. Through-hole structure; 111. First through-hole; 120. First section; 121. Main body; 122. Lug; 130. Second section;

[0026] 200, Plastic sealant; 210, Mounting hole.

[0027] 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

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] When a power module is connected to electrical equipment or structures (such as motors), the power terminals are subjected to connection forces during the bonding process, which may transmit stress to the molding compound. Under stress, the molding compound may be at risk of delamination or cracking.

[0033] Currently, increasing the length of power terminals is often used to increase their flexibility and reduce the possibility of stress being transmitted to the molding compound. However, increasing the length of power terminals inevitably increases the size of power devices and reduces their power density.

[0034] This utility model proposes a power module.

[0035] Please see Figure 1 In 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; wherein, the portion of the power terminal 100 exposed in the molding compound 200 is provided with a through-hole structure 110.

[0036] Understandably, during use, the power module needs to be connected to electrical equipment or structures, such as motors. That is, the exposed power terminals 100 in the power module are electrically connected to the electrical equipment or structure via bolts or welding. During bolting or welding, the exposed power terminals 100 will transmit the force they receive towards the encapsulated component 200. To prevent stress from being directly transmitted to the interior of the encapsulated component 200 and causing cracking, this invention provides a through-hole structure 110 on the power terminals 100 for absorbing stress.

[0037] The portion of the power terminal 100 exposed outside the molding compound 200 includes a through-hole area and a connection area. The through-hole area is used to house the through-hole structure 110, and the connection area is used to connect to electrical equipment or structures (such as motors). Understandably, when the power terminal 100 is electrically connected to an external source, stress is transmitted along the direction close to the molding compound 200. Correspondingly, the through-hole area is located on the side of the connection area close to the molding compound 200. Thus, when the power terminal 100 is connected to an electrical device or structure, the stress on the power terminal 100 is transmitted along the direction close to the molding compound 200. When this stress is transmitted to the through-hole structure 110, the power terminal 100 may undergo slight deformation at this point to absorb the stress, preventing the externally transmitted force from reaching the interior of the molding compound 200 and causing the molding compound 200 to crack.

[0038] 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, copper alloy, aluminum alloy, etc. The material of the power terminal 100 is not limited here. In one embodiment, the power terminal 100 is a terminal on the AC side of the power module.

[0039] 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 it. The power terminals 100 are electrically connected to the substrate and, through the substrate, to the chip assembly. The molding compound 200 covers the substrate, the chip assembly, and a portion of the power terminals 100. The portion of the power terminals 100 exposed in the molding compound 200 has a through-hole structure 110. This through-hole structure 110 serves several purposes. First, when the power terminals 100 are connected to electrical equipment or structures, the stress on the power terminals 100 is absorbed by the through-hole structure 110. This prevents external forces from being transmitted to the inside of the molding compound 200, thus avoiding cracking and improving the service life and reliability of the power module. On the other hand, compared to the existing technology, extending the portion of the power terminal 100 exposed in the molding compound 200 avoids increasing the size of the power module, which is beneficial for improving the power density of the power module. Simultaneously, it avoids the stray inductance increased by an excessively long power terminal 100, thus avoiding the reduction in switching efficiency caused by stray inductance, and consequently preventing a decrease in the power density of the power module. Furthermore, since the portion of the power terminal 100 exposed in the molding compound 200 does not require additional extension, current carrying capacity is guaranteed.

[0040] In an embodiment of this utility model, the portion of the power terminal 100 exposed outside the molding compound 200 includes a first segment 120 and a second segment 130 connected together. The first segment 120 is located on the side of the second segment 130 close to the molding compound 200, and the through hole structure 110 is provided in the first segment 120.

[0041] Specifically, the power terminal 100 has a certain length, width, and thickness, wherein the length direction of the power terminal 100 is also the direction in which it extends. Along the length direction of the power terminal 100, the portion of the power terminal 100 exposed outside the molding compound 200 includes a first segment 120 and a second segment 130 connected together, wherein the first segment 120 is disposed close to the molding compound 200, and the second segment 130 is disposed away from the molding compound 200. In this invention, a through-hole structure 110 is disposed in the first segment 120. It can be understood that the through-hole structure 110 is mainly used to absorb the stress when the power terminal 100 is connected to electrical equipment or structure, and to prevent the stress from being transmitted to the molding compound 200. Therefore, the through-hole structure 110 needs to be disposed between the connection area and the molding compound 200. To avoid the power terminal 100 from being too long, the through-hole structure 110 needs to be disposed close to the molding compound 200. That is, the through-hole structure 110 is located in the first section 120, thereby avoiding the excessive length of the power terminal 100 and thus ensuring the power density of the power module.

[0042] Understandably, along the length of the power terminal 100, the closer the through-hole structure 110 is to the molding compound 200, the more advantageous it is for shortening the length of the power terminal 100, thereby improving the power density of the power module. In one embodiment, the distance between the through-hole structure 110 and the molding compound 200 along the length of the power terminal 100 is 0.5mm-1.5mm. This avoids both excessive length of the power terminal 100 and the impact of excess adhesive from the edges of the molding compound 200 on the through-hole structure 110.

[0043] In an embodiment of this utility model, the width of the first segment 120 is greater than the width of the second segment 130.

[0044] Understandably, placing the through-hole structure 110 in the first segment 120 will inevitably occupy part of the current-carrying area of ​​the first segment 120. With a fixed current carrying capacity, the reduction in current-carrying area will inevitably lead to an increase in current density, thus significantly increasing the heat generation of the power terminal 100. To avoid increased heat generation at the first segment 120, the width of the first segment 120 is set to be greater than the width of the second segment to compensate for the portion occupied by the through-hole structure 110. Thus, the placement of the through-hole structure 110 does not sacrifice the current-carrying area of ​​the first segment 120, thereby preventing a significant increase in heat generation in the first segment 120 of the power terminal 100. Simultaneously, the strength of the first segment 120 itself is not weakened because the cross-sectional area is not reduced.

[0045] In one embodiment, the sum of the width of the second segment 130 and the width of the through-hole structure 110 is equal to the width of the first segment 120. Thus, in the width direction of the power module, the portion of the first segment 120 that is wider than the second segment 130 is exactly equal to the width of the through-hole structure 110, thereby making the current-carrying area of ​​the first segment 120 equal to that of the second segment 130. It is understood that the sum of the width of the second segment 130 and the width of the through-hole structure 110 equals the width of the first segment 120. Here, "equal to" does not mean absolutely equal, but rather approximately equal; it can be slightly greater or slightly less. The range of error is not limited here, as long as the heat generation of the first segment 120 does not increase and its structural strength is not weakened.

[0046] In an embodiment of this utility model, along the width direction of the power terminal 100, the first segment 120 includes a main body 121 and two protruding ears 122 disposed on opposite sides of the main body 121. Along the length direction of the power terminal 100, the projection of the second segment 130 overlaps with the main body 121. The through-hole structure 110 includes two first through holes 111 arranged at intervals. The two first through holes 111 are respectively disposed on the two protruding ears 122 and extend to the main body 121.

[0047] Specifically, the first segment 120 includes a main body 121 and two lugs 122 connected to each other. Along the width direction of the power terminal 100, one lug 122, the main body 121, and the other lug 122 are arranged in sequence. The main body 121 is disposed opposite to the second segment 130 and the two have the same width. That is, the opposite two sides of the second segment 130 in the width direction are aligned with the two pairs of opposite sides of the main body 121 in the width direction.

[0048] In the embodiment shown in the figures of this utility model, the through-hole structure 110 includes two spaced-apart first through holes 111, which are respectively disposed on two lug portions 122. It is understood that the first through holes 111 have a certain length and width. For ease of explanation, the length direction of the first through holes 111 is defined to be consistent with the length direction of the power terminal 100, and the width direction of the first through holes 111 is consistent with the width direction of the power terminal 100. The first through holes 111 are disposed on the lug portions 122, and the first through holes 111 extend to the main body portion 121 in the width direction.

[0049] Understandably, in this embodiment, the connection area is located in the second segment 130. When the second segment 130 is connected to electrical equipment or a structure, the force will be transmitted along the second segment 130 to the main body 121, and then to the molding compound 200. Compared to a structure where the first through hole 111 is only located in the lug 122, having the first through hole 111 located in the lug 122 and extending to the main body 121 allows the first through hole 111 to absorb the force in a timely manner, preventing some external force from being directly transmitted to the main body 121 through the second segment 130 and then to the interior of the molding compound 200, thus ensuring the stress relief effect of the through hole structure 110.

[0050] In an embodiment of this utility model, the power terminal 100 has a central axis extending along the length direction of the power terminal 100, and the through hole structure 110 is symmetrically arranged about the central axis.

[0051] Specifically, the power terminal 100 has a central axis extending along its length, meaning that the power terminal 100 is configured symmetrically in its width direction. Similarly, the through-hole structure 110 is symmetrically arranged about the central axis, meaning that the through-hole structure 110 is also configured symmetrically in its width direction. Thus, when a force is transmitted to the through-hole structure 110, and the through-hole structure 110 absorbs the force and undergoes slight deformation, this deformation will also be symmetrical along the width direction of the power module. This prevents the power terminal 100 from warping at one end in the width direction, ensuring the normal operation of the power terminal 100.

[0052] In one embodiment, the through-hole structure 110 includes two first through holes 111, as shown in the figures of this utility model. The two first through holes 111 are respectively disposed on the lug portion 122 and extend to the main body portion 121. In another embodiment, the through-hole structure 110 includes one first through hole 111, which is disposed on the main body portion 121, and the centerline of the first through hole 111 overlaps with the centerline axis.

[0053] In one embodiment, the through-hole structure 110 is configured as a rectangular hole, a circular hole, or an irregularly shaped hole. Here, the shape of the hole in the through-hole structure 110 is not limited.

[0054] In an embodiment of this invention, the power module further includes a metal boss (not shown) and signal terminals. 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 210 corresponding to the metal boss. The signal terminals pass through the mounting holes 210 and are electrically connected to the metal boss. Thus, the signal terminals are led out from the mounting holes 210 on one side surface of the molding compound 200, and the signal terminals form an electrical connection with the chip assembly through the metal boss and the substrate. This brings the signal terminals closer to the chip assembly, effectively reducing noise and improving the stability of the circuit current.

[0055] In an embodiment of this utility model, the power module further includes a heat sink (not shown), and the molding compound 200 is connected to the heat sink.

[0056] 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 210 is connected to the heat sink, which can be done by welding or hinge.

[0057] 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 by 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; The portion of the power terminal exposed outside the molding compound has a through-hole structure.

2. The power module of claim 1, wherein, The portion of the power terminal exposed in the molding compound includes a first segment and a second segment connected together. The first segment is located on the side of the second segment closer to the molding compound, and the through-hole structure is provided in the first segment.

3. The power module of claim 2, wherein, The width of the first segment is greater than the width of the second segment.

4. The power module of claim 3, wherein, Along the width direction of the power terminal, the first segment includes a main body and two protruding lugs disposed on opposite sides of the main body; along the length direction of the power terminal, the projection of the second segment overlaps with the main body. The through-hole structure includes two first through holes spaced apart, each first through hole being located on one of the two lug portions and extending to the main body portion.

5. The power module as described in claim 3, characterized in that, The sum of the width of the second segment and the width of the through-hole structure is equal to the width of the first segment.

6. The power module of claim 2, wherein, Along the length of the power terminal, the distance between the through-hole structure and the molding compound is 0.5mm-1.5mm.

7. The power module of claim 1, wherein, The power terminal has a central axis extending along the length direction of the power terminal, and the through-hole structure is symmetrically arranged about the central axis.

8. The power module of claim 1, wherein, The through-hole structure is configured as a rectangular hole, a circular hole, or an irregularly shaped hole.

9. The power module of claim 1, wherein, 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 of claim 1, wherein, The power module also includes a heat sink, and the molding compound is connected to the heat sink.

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