Power semiconductor with heatsink featuring a folded fin heatsink

Abstract

A power semiconductor assembly with a heat sink, comprising a semiconductor die, a plurality of pin terminals electrically coupled to the semiconductor die, a encapsulant that at least partially encloses the semiconductor die and the plurality of pin terminals, and a heat sink coupled to the assembly, wherein the heat sink includes a fin assembly having a plurality of fin members configured to receive a cooling fluid.

Description

Technical Field

[0001] The present disclosure relates to a power semiconductor with a heat sink including a bent fin heat sink.

Background Art

[0002] The present disclosure relates to a power semiconductor for use with a rotating electric machine. The power semiconductor can be used for various applications, for example, including inverting direct current (DC) power to angularly displace a rotor assembly relative to a stator assembly of the rotating electric machine.

[0003] Inversion of DC power can generate a large amount of heat, which may reduce the operating efficiency of the rotating electric machine. Cooling of the power semiconductor is considered beneficial.

Summary of Invention

[0004] In one embodiment of the present disclosure, a power semiconductor assembly with a heat sink includes: a semiconductor die; a plurality of pin terminals electrically coupled to the semiconductor die; a sealing body that at least partially encapsulates the semiconductor die and the plurality of pin terminals; and a heat sink coupled to the assembly, the heat sink including a fin assembly having a plurality of fin members configured to receive a cooling fluid.

[0005] In one embodiment of the present disclosure, a power semiconductor assembly with a heat sink includes: a semiconductor die; a plurality of pin terminals electrically coupled to the semiconductor die; a sealing body that at least partially encapsulates the semiconductor die and the plurality of pin terminals; a heat sink including a fin assembly having a plurality of fin members configured to receive a cooling fluid; and a heat sink base having a pair of first walls and a pair of second walls, the fin assembly being received within the pair of first walls and the pair of second walls.

[0006] In one embodiment of the present disclosure, the power semiconductor assembly with a heatsink includes a semiconductor die, a plurality of pin terminals electrically coupled to the semiconductor die, a encapsulant that at least partially encloses the semiconductor die and the plurality of pin terminals, a heatsink coupled to the assembly and including a fin assembly having a plurality of fin members configured to receive a cooling fluid, a seal pad coupled to the fin assembly and formed from a compressible material, and an inverter mounting body having a plurality of cavities formed to receive the power semiconductor with a heatsink, each of the plurality of cavities having a first side surface and a second side surface opposite to the first side surface, the first side surface being nonparallel to the second side surface such that the first side surface engages with the surface of the seal pad and biases the seal pad toward engagement with the fin assembly. [Brief explanation of the drawing]

[0007] The drawings described herein are for illustrative purposes only and do not illustrate all possible implementations, nor are they intended to limit the scope of this disclosure.

[0008] [Figure 1] Figure 1 is a perspective view of a power semiconductor with a heatsink configured according to the teachings of this disclosure.

[0009] [Figure 2] Figure 2 is a side view of the power semiconductor with a heatsink shown in Figure 1.

[0010] [Figure 3] Figure 3 is a front view of the power semiconductor with a heatsink shown in Figure 1.

[0011] [Figure 4] Figure 4 is a perspective view of a portion of the power semiconductor with a heatsink shown in Figure 1, illustrating the structure of the power semiconductor in more detail.

[0012] [Figure 5]FIG. 5 is a perspective view of a part of the power semiconductor with a heat sink of FIG. 1, showing the heat sink in more detail.

[0013] [Figure 6] FIG. 6 is a side view of the heat sink.

[0014] [Figure 7] FIG. 7 is a bottom view of the heat sink.

[0015] [Figure 8] FIG. 8 is a perspective view of a part of an inverter using a plurality of the power semiconductors with heat sinks of FIG. 1.

[0016] [Figure 9] FIG. 9 is a perspective view of a part of an inverter using a plurality of the power semiconductors with heat sinks of FIG. 1.

[0017] [Figure 10] FIG. 10 is an enlarged part of FIG. 9.

[0018] [Figure 11] FIG. 11 is a perspective view of one implementation of a power semiconductor with a heat sink.

[0019] [Figure 12] FIG. 12 is a perspective view of one implementation of a part of a power semiconductor with a heat sink.

[0020] [Figure 13] FIG. 13 is a perspective view of one implementation of a power semiconductor with a heat sink.

[0021] [Figure 14] FIG. 14 is a perspective view of one implementation of a power semiconductor with a heat sink.

[0022] [Figure 15]Figure 15 is a perspective view of one mounting configuration for a power semiconductor with a heatsink.

[0023] [Figure 16] Figure 16 is a perspective view of one mounting configuration for a power semiconductor with a heatsink.

[0024] [Figure 17] Figure 17 is a cross-sectional view of one mounting configuration of a power semiconductor with a heatsink.

[0025] Throughout the drawings, the corresponding reference numerals indicate the corresponding parts. Detailed description of the invention

[0026] Referring to Figures 1 to 3, an exemplary power semiconductor with a heatsink is denoted collectively by reference numeral 10. The power semiconductor with a heatsink 10 may include a power semiconductor 12 and a heatsink 14.

[0027] Referring to Figures 1 to 4, the power semiconductor 12 can be any type of power semiconductor, such as a transistor. For example, the power semiconductor 12 may be an insulated-gate bipolar transistor (IGBT), but in the specific example presented, it is a metal-oxide-semiconductor field-effect transistor (MOSFET). The power semiconductor 12 may include a semiconductor die 20, a plurality of pin terminals 22, a plate terminal 24, and a encapsulant 26. The semiconductor die 20 may have a plurality of semiconductor terminals (not specifically shown), each of which may be electrically coupled to a corresponding one of the plurality of pin terminals 22. In the example presented, the semiconductor die 20 has four semiconductor terminals, including a gate (not specifically shown), a source sense (not specifically shown), a source (not specifically shown), and a drain (not specifically shown). Each of the pin terminals 22 may be formed from an electrically conductive metallic material such as copper and may be electrically coupled to a corresponding semiconductor terminal. For example, each of the pin terminals 22 may be joined to one of the corresponding semiconductor terminals by solder material, thereby electrically and physically coupling the pin terminal 22 to one of the corresponding semiconductor terminals. Alternatively, one or more bond wires 30 may be used to electrically couple one of the pin terminals 22 to one of the corresponding semiconductor terminals. The plate terminal 24 may be electrically coupled to one of the pin terminals 22 and may be directly attached to one of the semiconductor terminals. In the presented example, pin terminal 22a is electrically coupled to the gate, pin terminal 22b is electrically coupled to the source sense, pin terminal 22c is electrically coupled to the source, and pin terminal 22d is electrically coupled to both the drain and the plate terminal 24. The plate terminal 24 is formed from a suitable electrically conductive metallic material such as copper. The encapsulant 26 is formed from an encapsulant material placed on the semiconductor die 20. The semiconductor die 20 and bond wires 30 are completely encapsulated within the encapsulant material, and the pin terminals 22 are partially encapsulated within the encapsulant material. Optionally, the plate terminal 24 may be partially sealed within the sealing material.

[0028] Referring to Figures 5 to 7, the heat sink 14 may have a body or heat sink base 40 and a fin assembly 42 fixedly coupled to the heat sink base 40 and projecting outward from the heat sink base 40. The heat sink base 40 may be formed from a suitable material such as copper and may be shaped to receive the fin assembly 42. In this respect, the heat sink base 40 defines a recess or cavity 44 capable of receiving the fin assembly 42. The cavity 44 is open at at least two ends, thereby allowing a flow of cooling fluid to pass through the cavity 44.

[0029] In the specific example presented, the heat sink base 40 has a rectangular tubular configuration comprising a pair of first walls 46 parallel to each other and a pair of second walls 48 parallel to each other and perpendicular to the first walls 46. Each of the second walls 48 is fixedly coupled to each end of the first walls 46. It should be understood that the heat sink base 40 may be formed from a tubular material having a different cross-sectional shape (e.g., triangular, circular, square, elliptical), and one or more sides of the heat sink base 40 may be formed to be at least partially "open," for example, as a channel.

[0030] The fin assembly 42 may comprise a plurality of fin members 50 and a plurality of ridges 52, each of which connects one of the fin members 50 to one of the adjacent fin members 50, thereby giving the fin assembly 42 a pleated structure. The fin assembly 42 may be formed from any desired material, such as a sheet of copper, aluminum, or stainless steel. In the particular example presented, the fin assembly 42 is formed from a folded copper sheet. If desired, the material forming the fin assembly 42 may be perforated and may be an "expanded" sheet (i.e., a sheet cut and stretched to form a regular pattern of mesh-like material) or mesh in its configuration.

[0031] The fin assembly 42 can be received within the cavity 44 in the heat sink base 40 and can be fixedly and thermally bonded to the heat sink base 40. For example, some or all of the peaks 52 can be bonded to a corresponding inner surface of one of the first walls 46 by soldering, brazing, welding, or sintering using a silver-based or copper-based sintering technique. The outer surface of one of the first walls 46 can be fixedly and thermally bonded to the plate terminal 24, for example, by soldering, brazing, or sintering.

[0032] Referring to Figures 8 to 10, a portion of an inverter 60 for an electric motor (not shown) is illustrated. Except as otherwise provided herein, the inverter 60 may be configured in the manner disclosed in International (PCT) Patent Application No. PCT / US2022 / 019900 filed March 11, 2022, or in U.S. Patent Application No. 17 / 838396 filed June 13, 2022, which are incorporated by reference as if they were described in detail in their entirety herein. In short, the inverter 60 comprises an inverter mounting body 62, a plurality of power semiconductors 10 with heat sinks, and a plurality of busbars, the plurality of busbars including a positive busbar 64, a negative busbar 66, and a plurality of phase busbars 68.

[0033] The inverter mounting body 62 is formed from an insulating plastic material and defines a base 70, an outer peripheral wall 72, an intermediate peripheral wall 74, an inner peripheral wall 76, and a plurality of cavities 78 radially arranged between the outer peripheral wall 72 and the intermediate peripheral wall 74. The cavities 78 are spaced apart from each other circumferentially around the intermediate peripheral wall 74. Multiple sets of terminal receiving portions (not specifically shown) are formed through the base 70, and each set of terminal receiving portions intersects with one of the corresponding cavities. Each of the multiple heatsink-equipped power semiconductors 10 is received in one of the corresponding cavities 78, and the pin terminals 22 of the power semiconductor 12 are received within the terminal receiving portions such that the pin terminals 22 extend through the base 70. The pin terminals 22 can be mechanically and electrically coupled to the positive busbar 64, the negative busbar 66, and the phase busbar 68, thereby electrically coupling the power semiconductor 12 to those busbars.

[0034] The cooling fluid can be supplied to the interior of the heat sink base 40 and to the fin assembly 42 in any desired manner. In the presented example, a plurality of coolant ports 80 are formed through the intermediate circumferential wall 74, allowing the cooling fluid to flow from the annular region between the inner circumferential wall 76 and the intermediate circumferential wall 74 to each of the cavities 78. In this respect, each of the coolant ports 80 creates fluid communication between a corresponding one of the cavities 78 and the annular region between the inner circumferential wall 76 and the intermediate circumferential wall 74.

[0035] Moving to Figure 11, another mounting configuration of the power semiconductor 10' with a heatsink is shown. The power semiconductor 10' with a heatsink may include a power semiconductor 12 and a heatsink 14'. The heatsink 14' may include a fin assembly 42' that defines a plurality of fin members 50 and a plurality of peaks 52, each of which peaks 52 connects one of the fin members 50 to one of the adjacent fin members 50, thereby giving the fin assembly 42' a pleated configuration. In one mounting configuration, the fin assembly 42' may include 22 fin members 50. The fin assembly 42' may be configured to be directly bonded or connected to the outer surface of the power semiconductor 12 without being enclosed by a wall. For example, the fin assembly 42' may be fixedly connected to a seal 26 or a plate terminal 24. In one mounting configuration, one or more of the peaks 52 may be directly bonded to the plate terminal 24, for example, by soldering or welding. The fin assembly 42' can be formed from any desired material, such as a sheet of copper, aluminum, or stainless steel. In one implementation, the fin assembly 42' is formed from a folded copper sheet.

[0036] Figure 12 shows another implementation of the fin assembly 42'. The fin assembly 42' may define a plurality of fin members 50 and a plurality of ridges 52', each ridge 52' connecting one of the fin members 50 to one of the adjacent fin members 50 to give the fin assembly 42 a creasing bend configuration. The creasing bend can be made by mechanically reducing the thickness of the material sheet used to form the fin assembly 42' at positions on the sheet corresponding to the locations where the ridges 52' exist in the assembled form, at periodic intervals or distances. A material sheet such as copper, aluminum, or stainless steel may be roll-formed to reduce the thickness of the sheet at the locations where the ridges 52' are formed. The ridges 52' may then be bent about 180 degrees at those locations. The process of periodically reducing the thickness of the sheet may create notches 86 on the surface 88 of the fin member 50 and on the opposing surfaces 90 of adjacent fin members 50. The notches 86 can define the start and end of the reduced thickness portion of the sheet. When the sheet is bent to form the fin assemblies 42' and the peaks 52', the notches 86 on the surface 88 of the fin member 50 and the notches 86 on the opposing surface 90 of the adjacent fin member 50 can position the surface 88 and the opposing surface 90 closer together compared to embodiments without notches 88. Such a configuration can improve the thermal conductivity of the fin assemblies 42' by reducing the distance between the surfaces 89,90, thereby increasing convection and concentrating more cooling surfaces near the power semiconductor with a heatsink.

[0037] Figures 13 to 17 show one mounting configuration of a power semiconductor 10' with a heat sink received within an inverter mounting body 60. The power semiconductor 10' with a heat sink can be mounted together with a seal pad 82 such that the seal pad 82 abuts against a first side surface 84 of the cavity 78, and the power semiconductor 10' with a heat sink abuts against a second side surface 86 of the cavity 78 opposite to the first side surface 84. The seal pad 82 may be substantially square or rectangular in shape when viewed in plan and may have a height that can be selected based on the amount of force exerted on the power semiconductor 10' with a heat sink by the seal pad 82. The seal pad 82 may be formed from a compressible material that can withstand the temperature of the fluid flowing over the power semiconductor 10' with a heat sink. In one mounting configuration, the seal pad 82 may be formed from closed-cell foam or a compressible elastomer material. The seal pad 82 can be compressed so that its outer surface closely abuts the fin assembly 42', forming a fluid seal between the seal pad 82 and the fin assembly 42', thereby preventing fluid flow through the cavity 78 at locations other than the fin assembly 42'. The outer surface of the seal body 26 can closely conform to the shape of the cavity 78 that receives the power semiconductor with heat sink 10', so that a fluid seal exists between the seal body 26 and the cavity 78 when the power semiconductor with heat sink 10' is received in the cavity 78. The first side surface 84 can have a surface that is not parallel to the second side surface 86, so when the power semiconductor with heat sink 10' and the seal pad 82 are received in the cavity 78, the seal pad 82 can be compressed and biased by the non-parallel first side surface 84 toward a sealed engagement of the power semiconductor with heat sink 10' with the fin assembly 42'. In other words, as the power semiconductor 10' with the heatsink and the seal pad 82 are moved to a position where the terminals extend through the terminal receiving portion, the non-parallel first side surface 84 compresses the seal pad 82 against the fin assembly 42'. In one mounting configuration, the first side surface 84 of the cavity 78 may be inclined at an angle between 10 and 20 degrees relative to the second side surface 86.

[0038] The above-described embodiments are provided for illustrative and explanatory purposes only. They are not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment and, where applicable, are interchangeable and can be used in selected embodiments, even if not specifically illustrated or described. They may also be modified in various ways. Such modifications will not be considered departures from the disclosure, and all such modifications are intended to be within the scope of the disclosure.

Claims

1. A power semiconductor assembly with a heatsink, Semiconductor die and Multiple pin terminals electrically coupled to the semiconductor die, A encapsulant that at least partially encloses the semiconductor die and the plurality of pin terminals, A heat sink coupled to the assembly, comprising a fin assembly having a plurality of fin members configured to receive a cooling fluid, and A power semiconductor assembly with a heatsink, including the heatsink.

2. The power semiconductor assembly with a heatsink according to claim 1, further comprising a sealing pad bonded to the fin assembly.

3. The power semiconductor assembly with a heat sink according to claim 2, wherein the seal pad is a compressible material that forms a fluid-resistant seal between the seal pad and the fin assembly.

4. The power semiconductor assembly with a heat sink according to claim 2, wherein the sealing pad is configured to contact a first side surface of the cavity, and the first side surface has a surface that is not parallel to a second side surface of the cavity that is opposite to the first side surface.

5. The power semiconductor assembly with a heat sink according to claim 1, wherein the fin assembly is configured to receive fluid at one end and transmit the fluid to the other end of the fin assembly.

6. The power semiconductor assembly with a heat sink according to claim 1, wherein the fin assembly includes a plurality of ridges connecting the fin members.

7. The power semiconductor assembly with a heat sink according to claim 1, wherein the fin assembly includes a bent flat sheet.

8. The power semiconductor assembly with a heat sink according to claim 1, wherein the fin assembly further includes a plurality of perforations.

9. The power semiconductor assembly with a heat sink according to claim 1, wherein the fin assembly further includes one or more notches in the peaks of the plurality of fin members.

10. The power semiconductor assembly with a heat sink according to claim 1, wherein the fin assembly further includes a reduced thickness portion between the surface of one of the plurality of fin members and one of the opposing fin members.

11. Semiconductor die and Multiple pin terminals electrically coupled to the semiconductor die, A encapsulant that at least partially encloses the semiconductor die and the plurality of pin terminals, A heat sink including a fin assembly having multiple fin members configured to receive a cooling fluid, A heat sink base having a pair of first walls and a pair of second walls, wherein the fin assembly is received within the pair of first walls and the pair of second walls. A power semiconductor assembly with a heatsink, including the heatsink.

12. The power semiconductor assembly with a heat sink according to claim 11, wherein the pair of first walls and the pair of second walls are substantially parallel to each other.

13. The power semiconductor assembly with a heat sink according to claim 11, wherein the fin assembly is configured to receive fluid at one end and transmit the fluid to the other end of the fin assembly.

14. The power semiconductor assembly with a heat sink according to claim 11, wherein the fin assembly includes a plurality of ridges connecting the fin members.

15. The power semiconductor assembly with a heat sink according to claim 14, wherein at least a portion of the plurality of peaks is fixedly attached to the heat sink base.

16. The power semiconductor assembly with a heat sink according to claim 11, wherein the fin assembly includes a folded flat sheet.

17. A power semiconductor assembly with a heatsink, Semiconductor die and Multiple pin terminals electrically coupled to the semiconductor die, A encapsulant that at least partially encloses the semiconductor die and the plurality of pin terminals, A heat sink coupled to the assembly, comprising a fin assembly having a plurality of fin members configured to receive a cooling fluid, A seal pad formed from a compressible material and bonded to the fin assembly, An inverter mounting body having a plurality of cavities formed to receive a power semiconductor with a heat sink, each of the plurality of cavities having a first side surface and a second side surface opposite to the first side surface, and the first side surface is non-parallel to the second side surface so that the first side surface engages with the surface of the seal pad and biases the seal pad to engage with the fin assembly, A power semiconductor assembly with a heatsink, including the heatsink.

18. The power semiconductor assembly with a heat sink according to claim 16, wherein a fluid-resistant seal is present between the seal pad and the fin assembly.

19. The power semiconductor assembly with a heat sink according to claim 16, wherein the sealing pad is made of closed-cell foam.

20. The power semiconductor assembly with a heat sink according to claim 16, wherein the first side surface of the cavity is inclined with respect to the second side surface at an angle between 10 and 20 degrees.

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