Power module, method for manufacturing power module, and power conversion device

Abstract

The purpose of the present invention is to provide a technique capable of reducing the stress applied to the interface between a main terminal and a molded part when the main terminal and a bus bar are connected using a bolt and a nut in a heat sink-integrated power module. The power module includes a semiconductor chip, a lead frame, a module base, a main terminal, a molded portion, a base portion, a heat sink, a bus bar, and a terminal block. A recessed portion in which a head portion of a nut or a bolt can be disposed is formed on a main terminal side of the terminal block, a bolt screwed with the nut disposed in the recessed portion or a nut screwed with the bolt disposed in the recessed portion is disposed on a side opposite to the terminal block with respect to the bus bar, and a rotation suppression portion is provided on an inner side surface of the recessed portion. The rotation restraining part restrains rotation of the head of the nut or the bolt arranged in the concave part.

Description

Technical Field

[0001] The present invention relates to a power module, a method for manufacturing a power module, and a power conversion device. Background Art

[0002] For example, Patent Document 1 discloses a heat sink-integrated power module comprising a power module unit, a fin base, and heat dissipation fins. The power module unit comprises a module base, a power semiconductor element mounted on the module base, and a molded portion that encapsulates the power semiconductor element. The fin base comprises a heat dissipation diffusion portion to which the heat dissipation fins are mounted, and a base portion formed on the heat dissipation diffusion portion and bonded to the module base. The module base is provided with a first concave-convex portion, and the base portion is provided with a second concave-convex portion that engages with the first concave-convex portion.

[0003] Patent Document 1: Japanese Patent No. 675904 Summary of the Invention

[0004] As the current flowing through the power module increases, the current flowing through the main terminals also increases, causing the temperature of the main terminals to rise. To suppress the temperature rise of the main terminals, bus bars (external terminals) are commonly connected to the main terminals.

[0005] However, when the main terminal and the bus bar are connected using bolts and nuts, stress is applied to the interface between the main terminal and the molded portion, and there is a concern that separation and cracks may occur at the interface.

[0006] Therefore, an object of the present invention is to provide a technology capable of reducing stress applied to the interface between a main terminal and a molded portion when connecting the main terminal and a bus bar using bolts and nuts in a heat sink-integrated power module.

[0007] The power module of the present invention comprises: a semiconductor element; a frame on which the semiconductor element is mounted on one surface; a module base on which the frame is arranged on one surface; a main terminal which is a part of the frame; a molded portion which encapsulates the semiconductor element, the frame and the module base in a manner such that the main terminal is exposed; a heat sink having a base portion and a plurality of heat dissipation fins, the base portion being integrated with the other surface of the module base exposed from the molded portion, the plurality of heat dissipation fins protruding toward the side of the base portion opposite to the module base; and an external terminal connected to the first main surface or the first main surface of the main terminal by bolts and nuts. a second main surface on the opposite side of the first main surface; and a structural component fixed to the base portion of the heat sink and arranged between the main terminal or the external terminal and the base portion, a recessed portion capable of arranging the head of the nut or the bolt is formed on the main terminal side of the structural component, the bolt threadedly engaged with the nut arranged in the recessed portion or the nut threadedly engaged with the bolt arranged in the recessed portion is arranged on the side opposite to the structural component relative to the external terminal, and a rotation inhibiting portion is provided on the inner side surface of the recessed portion, the rotation inhibiting portion inhibiting rotation of the head of the nut or the bolt arranged in the recessed portion.

[0008] Effects of the Invention

[0009] According to the present invention, when a bolt or nut located on the side opposite the structural component relative to the external terminal is tightened, the nut or bolt located in the recess can move toward the main terminal. Therefore, the main terminal will displace until the bolt or nut located on the side opposite the structural component relative to the external terminal contacts the nut or bolt located in the recess. However, if the bolt or nut located on the side opposite the structural component relative to the external terminal contacts the nut or bolt located in the recess, the main terminal will not displace further, and the nut or bolt located in the recess will move toward the main terminal. In other words, the displacement of the main terminal when the bolt and nut are used to connect the main terminal and the external terminal is limited to the gap between the bolt and nut.

[0010] Thus, in the heat sink-integrated power module, it is possible to reduce stress applied to the interface between the main terminal and the mold portion when the main terminal and the external terminal are connected using bolts and nuts.

[0011] The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a cross-sectional view of the power module according to the first embodiment.

[0013] Figure 2 This is a plan view of the power module according to the first embodiment.

[0014] Figure 3 This is a plan view of a power module according to a modified example of the first embodiment.

[0015] Figure 4 This is a cross-sectional view showing the connection between a main terminal and a bus bar included in a power module according to a modification of the first embodiment.

[0016] Figure 5 This is a plan view of a power module according to a modified example of the first embodiment.

[0017] Figure 6 This is a plan view of a power module according to a modified example of the first embodiment.

[0018] Figure 7 This is a cross-sectional view showing the connection between the main terminal and the bus bar included in the power module according to the first embodiment, achieved by bolt fastening.

[0019] Figure 8 This is a plan view showing the connection between the main terminal and the bus bar included in the power module according to the first embodiment, achieved by bolt fastening.

[0020] Figure 9 This is a cross-sectional view showing a gap between a main terminal and a terminal block included in the power module according to the first embodiment.

[0021] Figure 10 This is a cross-sectional view showing connection between a main terminal and a bus bar by bolt fastening in a case where a gap exists between the main terminal and the terminal block included in the power module according to the first embodiment.

[0022] Figure 11 This is a cross-sectional view showing the connection between a main terminal and a bus bar included in a power module according to a modification of the first embodiment, achieved by bolt fastening.

[0023] Figure 12 This is a cross-sectional view showing the connection between a main terminal and a bus bar included in a power module according to a modification of the first embodiment, achieved by bolt fastening.

[0024] Figure 13 This is a cross-sectional view showing the connection between a main terminal and a bus bar included in a power module according to a modification of the first embodiment, achieved by bolt fastening.

[0025] Figure 14 This is a plan view of a terminal block and a nut included in the power module according to the first embodiment.

[0026] Figure 15 This is a plan view of a terminal block and a nut included in a power module according to a modification of the first embodiment.

[0027] Figure 16 This is a plan view of a terminal block and a nut included in a power module according to a modification of the first embodiment.

[0028] Figure 17 This is a plan view of a terminal block and a nut included in a power module according to a modification of the first embodiment.

[0029] Figure 18 This is a plan view of a terminal block and a nut included in a power module according to a modification of the first embodiment.

[0030] Figure 19 This is a cross-sectional view showing the connection between the terminal block and the heat sink included in the power module according to the first embodiment, which are fastened by bolts.

[0031] Figure 20 This is a plan view showing the connection between the terminal block and the heat sink included in the power module according to the first embodiment, achieved by bolt fastening.

[0032] Figure 21 This is a cross-sectional view showing the connection between a terminal block and a heat sink included in a power module according to a modification of the first embodiment, using solder.

[0033] Figure 22 This is a cross-sectional view showing the connection between a terminal block and a heat sink included in a power module according to a modification of the first embodiment, achieved by welding.

[0034] Figure 23 This is a cross-sectional view showing the connection between a terminal block included in a power module according to a modification of the first embodiment and a heat sink achieved by compression bonding.

[0035] Figure 24 This is a cross-sectional view showing the arrangement of a terminal block having a positioning structure included in a power module according to a modification of the first embodiment.

[0036] Figure 25 These are a cross-sectional view, a side view, and a plan view showing the arrangement of a terminal block having a positioning structure included in a power module according to a modification of the first embodiment.

[0037] Figure 26 This is a cross-sectional view of a power module according to a modified example of the first embodiment.

[0038] Figure 27 This is a cross-sectional view of a power module according to a modified example of the first embodiment.

[0039] Figure 28 This is a cross-sectional view of a power module according to a modified example of the first embodiment.

[0040] Figure 29This is a cross-sectional view of a power module according to Embodiment 2.

[0041] Figure 30 This is a cross-sectional view showing the connection between a main terminal included in a power module according to the second embodiment and a bus bar fastened by bolts.

[0042] Figure 31 This is a plan view of a terminal block, a nut, and a nut retaining member included in a power module according to a second embodiment.

[0043] Figure 32 This is a cross-sectional view showing the connection between a main terminal included in a power module according to a modification of the second embodiment and a bus bar, which is achieved by bolt fastening.

[0044] Figure 33 This is a cross-sectional view of a power module according to Embodiment 3.

[0045] Figure 34 This is a cross-sectional view showing a state of main terminals and bus bars included in a power module according to a third embodiment before bolts are tightened.

[0046] Figure 35 This is a cross-sectional view showing the connection between a main terminal included in a power module according to a third embodiment and a bus bar fastened by bolts.

[0047] Figure 36 This is a plan view of a terminal block, a nut, and a nut retaining member included in a power module according to a third embodiment.

[0048] Figure 37 This is a cross-sectional view showing a state of main terminals and bus bars included in a power module according to a modification of the third embodiment before bolts are tightened.

[0049] Figure 38 This is a cross-sectional view showing a state of main terminals and bus bars included in a power module according to a modification of the third embodiment before bolts are tightened.

[0050] Figure 39 This is a block diagram showing the configuration of a power conversion system to which the power conversion device according to the fourth embodiment is applied. DETAILED DESCRIPTION

[0051] <Implementation Method 1>

[0052] Next, Embodiment 1 will be described using the drawings. Figure 1 This is a cross-sectional view of the power module 202 according to the first embodiment. Figure 2 This is a plan view of the power module 202 according to the first embodiment.

[0053] like Figure 1and Figure 2 As shown, the power module 202 is a heat sink integrated power module, which includes a power module unit 9 and a heat sink 16. The power module unit 9 includes a plurality of semiconductor chips 1

[0054] (semiconductor element), lead frame 3 (frame), insulating sheet 4, module base 5, molded portion 8, and multiple busbars 10 (external terminals). A terminal block is placed on the heat sink 16. The terminal block has the following characteristics: the nut is mounted in a state where rotation is suppressed and it can move toward the main terminal 7 and the heat sink 16.

[0055] Multiple semiconductor chips 1 are mounted on the upper surface (one surface) of a lead frame 3. The lead frame 3 is arranged with an insulating sheet 4 attached to the upper surface (one surface) of a module base 5 interposed therebetween. A molded portion 8 is formed of a resin material and encapsulates the semiconductor chips 1, lead frame 3, insulating sheet 4, and module base 5, with the main terminals 7, a portion of the lead frame 3, and the lower surface (the other surface) of the module base 5 exposed.

[0056] The heat sink 16 has: a base portion 14, which is integrated with the lower surface (the other surface) of the module base 5; and a plurality of heat dissipation fins 15, which protrude downward (on the opposite side of the module base 5) from the base portion 14. A plurality of concave fitting portions 5a are provided on the lower surface (the other surface) of the module base 5. In addition, a plurality of convex fitting portions 14a that can fit with the fitting portions 5a are provided on the upper surface (the surface on the module base 5 side) of the base portion 14. By fitting the fitting portions 5a and the fitting portions 14a, the module base 5 and the heat sink 16 are integrated. The fitting portions 5a and the fitting portions 14a can be respectively provided continuously in the depth direction of the module base 5 and the base portion 14, or can be provided intermittently. In addition, the convex and concave shapes of the fitting portion 5a of the module base 5 and the fitted portion 14a of the base portion 14 of the heat sink 16 are not limited to this. Even if the fitting portion 5a of the module base 5 is set to a convex shape, or the fitted portion 14a of the base portion 14 of the heat sink 16 is set to a concave shape, the same effect can be obtained.

[0057] The heat sink 16 is formed in a rectangular shape in a plan view. Two terminal blocks 13 (structural components) are fixed to both ends of the base portion 14 of the heat sink 16. Each terminal block 13 is arranged between the main terminal 7 and the base portion 14.

[0058] Furthermore, by performing molding for forming terminals after molding, control terminals 6 and main terminals 7, which are part of lead frame 3, are formed. However, molding for forming terminals is not essential and can be omitted.

[0059] Next, the main terminals 7 and control terminals 6 are described. The main terminals 7 and control terminals 6 are part of the lead frame 3 and are connected to the semiconductor chip 1 within the molded portion 8 via wiring members such as aluminum wires (not shown). However, the wiring members do not necessarily have to be aluminum wires; for example, electrical connections can be made using metal wires such as copper wires or metal plates using bonding members such as solder. The main terminals 7 and control terminals 6 are integrated by molding, being exposed from the molded portion 8.

[0060] Multiple (four) main terminals 7 extend in the left-right direction (first direction), parallel to the base portion 14 of the heat sink 16, and are exposed from the molded portion 8. Specifically, two main terminals 7 are formed in a straight line, extending leftward from the left end of the molded portion 8, and the remaining two main terminals 7 are formed in a straight line, extending rightward from the right end of the molded portion 8. The lower surfaces (second principal surfaces) of the main terminals 7 face the heat sink 16, and the upper surfaces (first principal surfaces) of the main terminals 7 face upward (opposite the heat sink 16).

[0061] Here, when the current flowing through the power module 202 is high, the thickness of the lead frame 3 including the main terminals 7 and the control terminals 6 is often increased from the perspective of current density. Therefore, if an attempt is made to bend the thick lead frame 3 during terminal forming processing, the press tonnage increases, which may lead to an increase in equipment size and a decrease in productivity.

[0062] As described above, in the first embodiment, the lower surfaces (second principal surfaces) of the main terminals 7 face the heat sink 16, while the upper surfaces (first principal surfaces) of the main terminals 7 face upward (opposite the heat sink 16). Specifically, the main terminals 7, which have a large terminal cross-sectional area, are formed to extend horizontally relative to the molded portion 8, eliminating the need for terminal forming processing on both the upper and lower surfaces of the main terminals 7. Since terminal forming processing is performed only on the control terminals 6, which have a small terminal cross-sectional area, as needed, this eliminates the need for larger equipment and improves productivity.

[0063] In addition, since the terminal forming process of the main terminal 7 is not required, the length of the main terminal 7 does not need to be extended in order to form the terminal, and the length of the main terminal 7 can be shortened. In accordance with the shortening of the length of the main terminal 7, the area of ​​the lead frame 3 including the main terminal 7 can be reduced. As a result, a large number of lead frame shapes can be obtained from one lead frame (large-scale acquisition), which can improve productivity. Alternatively, in accordance with the shortening of the length of the main terminal 7, the area of ​​the lead frame 3 within the power module 202 can be expanded while the area of ​​the lead frame 3 including the main terminal 7 remains unchanged. As a result, it is possible to achieve an increase in the design freedom of the configuration of the semiconductor chip 1 and the electrical wiring, and an improvement in heat dissipation.

[0064] Figure 3(a) and (b) are top views of a power module 202 according to a modification of the first embodiment. Figure 3 As shown in (a), the main terminal 7 may be L-shaped when viewed from above. Figure 3 As shown in (b), the main terminal 7 can also be in a "コ" shape when viewed from above. However, the shape of the main terminal 7 is not limited to this and can be freely designed. By setting it to such a shape, the stress applied to the interface between the main terminal 7 and the molded portion 8 when the main terminal 7 is connected to the bus bar 10 can be reduced. In addition, the stress applied to the interface between the main terminal 7 and the molded portion 8 when vibration occurs during product use can also be reduced, thereby improving the vibration resistance of the product.

[0065] Figure 4 1 is a cross-sectional view showing the connection between the main terminal 7 and the bus bar 10 of the power module 202 according to the modification of the first embodiment. Figure 4 As shown, the main terminal 7 can also have a crank shape when viewed in cross-section. Specifically, the main terminal 7 includes a first parallel portion 7a that protrudes from the molded portion 8 in a first direction, parallel to the base portion 14 of the heat sink 16; a first vertical portion 7b that extends vertically from the first parallel portion 7a in a second direction; and a second parallel portion 7c that extends from the first vertical portion 7b in the first direction. The bus bar 10 is connected to the first main surface of the second parallel portion 7c of the main terminal 7.

[0066] like Figure 4 As shown in FIG, by bending the main terminal 7 during the terminal forming process, the bent portion has an elastic function, thereby reducing the stress applied to the interface between the main terminal 7 and the molded portion 8 when the main terminal 7 is connected to the bus bar 10. Similarly, the stress applied to the interface between the main terminal 7 and the molded portion 8 when vibration occurs during product use can also be reduced, thereby improving the vibration resistance of the product. In addition, although Figure 4 The shape of the main terminal 7 shown requires bending, but since the second parallel portion 7 c extends in the horizontal direction, for example, one bus bar 10 having a large area can be connected to two main terminals 7 in a stable state.

[0067] Here, as Figure 2 As shown, the power module 202 according to the first embodiment has a structure in which main terminals 7 are arranged on two sides of the mold portion 8 and control terminals 6 are arranged on the other two sides in a plan view. However, the arrangement of the main terminals 7 and the control terminals 6 is not limited to this. Figure 5 and Figure 6 FIG. 2 is a top view of a power module 202 according to a modification of the first embodiment. Figure 5 As shown, the main terminal 7 is configured on one side and the control terminal 6 is configured on the other two sides. Figure 6As shown, the main terminals 7 and control terminals 6 are mixed and arranged on one side, allowing for flexible design. By arranging the main terminals 7 and control terminals 6 on multiple sides of the power module 202, there is an advantage in that the design freedom of the electrical wiring (e.g., aluminum wire) within the power module 202 is increased.

[0068] Figure 7 This is a cross-sectional view showing the connection between the main terminal 7 and the bus bar 10 included in the power module 202 according to the first embodiment, which is achieved by bolt fastening. Figure 8 This is a plan view showing the connection between the main terminal 7 and the bus bar 10 included in the power module 202 according to the first embodiment, which is achieved by bolt fastening. Figure 9 This is a cross-sectional view showing a gap 18 between a main terminal 7 and a terminal block 13 included in a power module 202 according to the first embodiment. Figure 10 This is a cross-sectional view showing connection between the main terminal 7 and the bus bar 10 by bolt fastening when a gap 18 exists between the main terminal 7 and the terminal block 13 included in the power module 202 according to the first embodiment.

[0069] like Figure 7 As shown, the method of connecting the main terminal 7 and the bus bar 10 by bolt fastening using the bolts 11 and nuts 12 can achieve the connection most simply and efficiently. The bolt fastening will be described.

[0070] A recess 17 is formed in the upper portion of each terminal block 13 (on the main terminal 7 side of each terminal block 13) in which the head of the nut 12 or the bolt 11 can be placed. The recess 17 includes a first recess 17a and a second recess 17b. The first recess 17a constitutes the upper portion of the recess 17. The second recess 17b is formed further below the first recess 17a (on the heat sink 16 side) and constitutes the lower portion of the recess 17. The first recess 17a and the second recess 17b are connected, and the first recess 17a has a larger outline when viewed from above (on the main terminal 7 side) than the second recess 17b.

[0071] Specifically, the first recess 17a is sized to accommodate the heads of the nut 12 and bolt 11. Furthermore, the second recess 17b is sized to accommodate the shaft of the bolt 11, which is threadedly engaged with the nut 12 positioned in the first recess 17a. Furthermore, a rotation-restricting portion is provided on the inner surface of the first recess 17a to restrict rotation of the heads of the nut 12 or bolt 11 positioned in the first recess 17a.

[0072] like Figure 8As shown, a notch 7d is previously provided in the main terminal 7, and a notch 10a is provided in a portion of the bus bar 10 corresponding to the notch 7d. With the shaft of a bolt 11 inserted through the notch 10a and the notch 7d, the main terminal 7 and the bus bar 10 are fastened to each other by tightening a nut 12 onto the shaft of the bolt 11.

[0073] Due to the tolerance of each component and the warping of the molded part 8, Figure 9 As shown in FIG. 1 , the positional relationship between the main terminal 7 and the terminal block 13 in the height direction is not necessarily such that the gap 18 is zero. Figure 9 As shown, a gap 18 exists between the main terminal 7 and the terminal block 13, or the main terminal 7 interferes with the terminal block 13. When the gap 18 between the main terminal 7 and the terminal block 13 is large, the displacement between the main terminal 7 and the bus bar 10 when the main terminal 7 and the bus bar 10 are connected becomes larger.

[0074] Therefore, if Figure 10 As shown in FIG. 1 , a large stress is applied to the interface between the molded portion 8 and the main terminal 7 when the bolt is tightened, and there is a concern that peeling and cracking may occur at the interface. However, in the first embodiment, the rotation of the nut 12 is suppressed, and the nut 12 is arranged in a state where it can move toward the main terminal 7 side and the heat sink 16 side. Therefore, as shown in FIG. Figure 7 As shown, the nut 12 can move toward the main terminal 7 when the bolt is tightened.

[0075] Therefore, when bolting the main terminal 7 to the bus bar 10, the main terminal 7 will displace until the bolt 11 and nut 12 contact. However, once the bolt 11 and nut 12 contact, the displacement of the main terminal 7 will not change further, and the nut 12 will move toward the main terminal 7. In other words, the displacement of the main terminal 7 when bolting the main terminal 7 to the bus bar 10 is limited to the gap 18 between the bolt 11 and nut 12, rather than the gap 18 between the main terminal 7 and the terminal block 13. Therefore, in the first embodiment, the stress applied to the interface between the molded portion 8 and the main terminal 7 can be reduced, allowing the main terminal 7 and the bus bar 10 to be connected with high productivity.

[0076] Figure 11 、 Figure 12 (a), (b) and Figure 13 This is a cross-sectional view showing the connection between the main terminal 7 and the bus bar 10 included in the power module 202 according to the modification of the first embodiment, which is achieved by bolt fastening.

[0077] In addition, you can also Figure 7As shown, the bus bar 10 is arranged on the upper side of the main terminal 7 (opposite to the heat sink 16), the bolt 11 is arranged on the upper side of the bus bar 10, and the terminal block 13 and the nut 12 are arranged on the lower side of the main terminal 7 (heat sink 16 side), and the connection is made by fastening the bolts. Figure 11 As shown, a bus bar 10 is placed below the main terminal 7, a bolt 11 is placed above the main terminal 7, and a terminal block 13 and a nut 12 are placed below the bus bar 10, and the terminals are connected by fastening with the bolts.

[0078] In addition, you can also Figure 12 In the configurations shown in (a) and (b), the bolts 11 and nuts 12 are swapped, with the nuts 12 positioned on the upper side and the terminal block 13 and bolts 11 positioned on the lower side, and the connection is achieved by bolting. When the terminal block 13 and bolts 11 are positioned on the lower side and bolted, the bolts 11 are positioned on the terminal block 13 so that they can move toward the main terminals 7 and the heat sink 16. Rotating the nuts 12 allows the bolts 11 to move toward the main terminals 7. In this configuration, the shafts of the bolts 11 can simultaneously position the main terminals 7 and the busbar 10.

[0079] exist Figure 7 In the structure shown, the second recess 17b of the terminal block 13 functions as a relief portion for the bolt 11. Figure 13 As shown in FIG, if the bolt 11 does not interfere with the terminal block 13, the second recess 17b serving as a relief portion for the bolt 11 is not necessary, and only the first recess 17a is provided. Figure 12 As shown in (a) and (b), even when the head of the bolt 11 is arranged in the recess 17 of the terminal block 13, the second recess 17b is not required.

[0080] Next, the rotation suppressing portion that suppresses the rotation of the head of the nut 12 or the bolt 11 disposed in the recessed portion 17 will be described. Figure 14 This is a plan view of the terminal block 13 and the nut 12 included in the power module 202 according to the first embodiment. Figures 15 to 18 It is a plan view of a terminal block 13 and a nut 12 included in a power module 202 according to a modification of the first embodiment.

[0081] like Figure 7 and Figure 14As shown, the terminal block 13 is provided with a hexagonal recess 17 (specifically, the first recess 17a) when viewed from above (viewed from the main terminal 7 side). A nut 12 is arranged in the recess 17, which is hexagonal when viewed from above. The rotation of the nut 12 is suppressed, and the nut 12 can move toward the main terminal 7 side and the heat sink 16 side. At this time, in order to suppress the rotation of the nut 12, it is necessary to make the minimum width of the recess 17 smaller than the maximum width of the nut 12. Here, the minimum width of the recess 17 refers to the minimum distance between the opposite sides of the hexagonal recess 17, that is, the diameter of the inscribed circle of the hexagonal recess 17. The maximum width of the nut 12 refers to the maximum distance between the opposite corners of the hexagonal nut 12, that is, the diameter of the circumscribed circle of the hexagonal nut 12.

[0082] Furthermore, when the head of the bolt 11 is disposed in the recess 17, the minimum width of the recess 17 needs to be smaller than the maximum width of the head of the bolt 11 in order to suppress the rotation of the bolt 11. Here, the rotation suppressing portion that suppresses the rotation of the nut 12 or the head of the bolt 11 disposed in the recess 17 is configured based on the relationship between the minimum width of the recess 17 and the maximum widths of the heads of the nut 12 and the bolt 11.

[0083] However, the structure of the terminal block 13 and the nut 12 is not limited to Figure 14 For example, Figure 15 As shown in (a) and (b), at least one protrusion 19 protruding inward may be formed on the inner side of the recess 17. In this structure, Figure 16 As shown in (a) and (b), at least one protrusion 19 is damaged by the tightening torque of the bolt 11 during busbar connection, eliminating the rotation-restraining effect of the nut 12. This allows the nut 12 to move toward the main terminal 7 and heat sink 16. This structure allows the nut 12 to be positioned in the recess 17 of the terminal block 13 during fabrication, allowing the terminal block 13 to be transported without falling out. This eliminates the need to position the nut 12 in the terminal block 13 during assembly of the power module 202, improving productivity.

[0084] The shape of the protrusion 19 can be Figure 15 and Figure 16 The circle shown in FIG can also be any shape such as a quadrilateral or a triangle. Figure 17 As shown, it is also possible to make the recess 17 in a manner that interferes with the nut 12, and press the nut 12 into the structure. In this structure, by adjusting the amount of interference between the recess 17 and the nut 12, it is possible to achieve the following effect, that is, the nut 12 will not fall off due to the vibration applied during transportation, and the pressed nut 12 will be disengaged from the recess 17 of the terminal block 13 by the tightening torque of the bolt 11 when connecting the busbar, and the nut 12 will move toward the main terminal 7 side. In this case, it can be as shown in FIG. Figure 17 As shown, the recess 17 as a whole interferes with the nut 12, and it can also be as shown in FIG. Figure 18 (a), (b), and (c) show structures in which only a portion of the recess 17 interferes with the nut 12.

[0085] Figure 19 This is a cross-sectional view showing the connection between the terminal block 13 and the heat sink 16 included in the power module 202 according to the first embodiment, which are fastened by bolts. Figure 20 This is a plan view showing the connection between the terminal block 13 and the heat sink 16 included in the power module 202 according to the first embodiment, which are fastened by bolts. Figure 21 1 is a cross-sectional view showing connection between a terminal block 13 and a heat sink 16 included in a power module 202 according to a modification of the first embodiment, using solder 2 . Figure 22 This is a cross-sectional view showing the connection between the terminal block 13 and the heat sink 16 included in the power module 202 according to the modification of the first embodiment, achieved by welding. Figure 23 1 is a cross-sectional view showing connection between a terminal block 13 and a heat sink 16 included in a power module 202 according to a modification of the first embodiment, achieved by pressure bonding.

[0086] The connection between the terminal block 13 and the base portion 14 of the heat sink 16 can also be made using Figure 19 and Figure 20 The connection shown is achieved by bolting, Figure 21 The connection is achieved by a bonding material such as solder 2, Figure 22 The connection shown is made by welding, or Figure 23 Any connection method such as the connection by crimping shown. Figure 22 Reference numeral 20 indicates a welded portion. Figure 23 Reference numeral 20a denotes a crimping portion.

[0087] exist Figures 19 to 23 The terminal block 13 is connected to the base portion 14 of the heat sink 16, but is not limited thereto. For example, Figure 24 As shown, a positioning groove 22a is provided in the base portion 14 of the heat sink 16, and a convex positioning portion 22 that can fit into the groove 22a is provided on the terminal block 13 to fix the terminal block 13 to the base portion 14 of the heat sink 16. This simplifies the installation process of the terminal block 13 and improves productivity.

[0088] Figure 25 (a) and (b) are cross-sectional views showing the arrangement of a terminal block 13 having a positioning structure included in a power module 202 according to a modification of the first embodiment. Figure 25 (c) is a side view. In addition, Figure 25(d) and (e) are plan views showing the arrangement of the terminal block 13 having the positioning structure included in the power module 202 according to the modification of the first embodiment.

[0089] The positioning portion of the terminal block 13 is not limited to Figure 24 The structure shown, for example, can be Figure 25 The structures shown in (a) to (e) determine the position of the terminal block 13 in at least one direction, and any structure may be used. Figure 25 As shown in (a), a positioning groove 22a is provided in the terminal block 13, and a T-shaped positioning portion 22 is provided on the base portion 14 when viewed in cross section. Alternatively, Figure 25 As shown in (b), the lower end of the terminal block 13 is entirely provided as a positioning portion, and a groove 22a that can be engaged with the positioning portion is provided in the base portion 14. Alternatively, Figure 25 As shown in (c), two convex positioning parts 22 are provided on the base part 14, and two grooves 22a are provided on the terminal block 13. Alternatively, Figure 25 As shown in (d), the positioning portion 22 provided on the base portion 14 is in the shape of two cross-shaped connections when viewed from above. Alternatively, Figure 25 As shown in (e), both positioning portions 22 provided on the base portion 14 are cylindrical. Alternatively, the terminal block 13 may be fixed to the heat sink 16 by combining multiple methods such as bolt fastening after the terminal block 13 is positioned by the positioning portions 22 .

[0090] Figures 26 to 28 FIG is a cross-sectional view of a power module 202 according to a modified example of the first embodiment. Figure 1 Figure 2 shows an example of a riveted heat sink 16, in which a base 14 and a plurality of heat dissipating fins 15 are integrated by riveting. Base 14 is made of aluminum or an aluminum alloy, processed by machining, die casting, forging, or extrusion. Using a plate material such as aluminum or an aluminum alloy allows for both workability and heat dissipation performance for heat dissipating fins 15.

[0091] However, the materials of the base 14 and the heat dissipation fins 15 are not limited to aluminum, and may be a combination of different materials. For example, from the perspective of heat dissipation capacity, by using the heat dissipation fins 15 as a copper plate having a higher thermal conductivity than aluminum, the heat dissipation capacity can be further improved compared to the case of aluminum. Figure 1 The riveted heat sink shown can also be Figure 26 The extruded heat sink made by extrusion, the cut heat sink made by cutting, or the forged heat sink made by forging shown can also be Figure 27The die-cast heat sink shown is manufactured by die-casting.

[0092] A mating portion 5a is provided on the lower surface (the other side) of the module base 5, and an engaged portion 14a that engages with the mating portion 5a is provided on the upper surface (the surface facing the module base 5) of the base portion 14 of the heat sink 16. The mating of the mating portion 5a and the engaged portion 14a integrates the module base 5 and the heat sink 16. Therefore, the integration of the module base 5 and the heat sink 16 can be achieved through a room temperature process, which reduces the size and complexity of the equipment used for the integration, thereby improving productivity.

[0093] However, you can also Figure 28 As shown, the module base 5 and heat sink 16 are integrated using a bonding material such as solder 2. Alternatively, the module base 5 and heat sink 16 can be integrated using a combination of methods, such as riveting and bonding materials. The module base 5 is processed by machining, die casting, forging, or extrusion, and is made of aluminum or an aluminum alloy. However, the material of the module base 5 is not limited to aluminum. Using a copper-based plate, which has a higher thermal conductivity than aluminum-based materials, further improves heat dissipation compared to aluminum-based materials.

[0094] The semiconductor chip 1 may be made of silicon, or may be made of a wide-bandgap semiconductor such as silicon carbide or gallium nitride.

[0095] From the viewpoint of resistivity and workability, the lead frame 3 and the bus bar 10 are preferably made of a copper-based material or an aluminum-based material, but are not limited thereto as long as they are metal materials.

[0096] From the perspectives of workability and insulation, the terminal block 13 is formed of resin. However, the terminal block 13 does not necessarily need to be formed of resin; it can also be formed of a metal material. Furthermore, if it is necessary to ensure the insulation distance between the lead frame 3 and the heat sink 16, and the insulation distance between the lead frame 3 and the nut 12, the terminal block 13 can also be formed of a composite material, such as a metal material covered with a resin material.

[0097] <Effect>

[0098] As described above, in embodiment 1 and its variations, the power module 202 includes: a semiconductor chip 1; a lead frame 3 having the semiconductor chip 1 mounted on one surface; a module base 5 having the lead frame 3 arranged on one surface; a main terminal 7, which is a part of the lead frame 3; a molded portion 8, which encapsulates the semiconductor chip 1, the lead frame 3, and the module base 5 in a manner such that the main terminal 7 is exposed; a heat sink 16, which includes a base portion 14 and a plurality of heat dissipation fins 15, wherein the base portion 14 is integrated with the other surface of the module base 5 exposed from the molded portion 8, and the plurality of heat dissipation fins 15 protrude toward the side of the base portion 14 opposite to the module base 5; a bus bar 10, which is connected to the first main surface or the second main surface opposite to the first main surface of the main terminal 7 by a bolt 11 and a nut 12; and a terminal block 13, which is fixed to the base portion 14 of the heat sink 16 and is arranged between the main terminal 7 or the bus bar 10 and the base portion 14. A recess 17 in which the head of a nut 12 or a bolt 11 can be arranged is formed on the main terminal 7 side of the terminal block 13, and a bolt 11 screwed together with the nut 12 arranged in the recess 17 or a nut 12 screwed together with the bolt 11 arranged in the recess 17 is arranged on the side opposite to the terminal block 13 relative to the bus bar 10, and a rotation inhibiting portion is provided on the inner side surface of the recess 17, which inhibits the rotation of the head of the nut 12 or the bolt 11 arranged in the recess 17.

[0099] Specifically, when viewed from the side of the main terminal 7, the recess 17, the nut 12 and the head of the bolt 11 are formed into a hexagon, the minimum width of the recess 17 is smaller than the maximum width of the head of the nut 12 and the bolt 11, and the rotation inhibiting portion is formed based on the relationship between the minimum width of the recess 17 and the maximum width of the head of the nut 12 and the bolt 11.

[0100] In addition, the manufacturing method of the power module 202 includes: step (a), in which the head of the nut 12 or the bolt 11 is arranged in the recess 17 when the bus bar 10 is arranged on the first main surface or the second main surface of the main terminal 7, and the bolt 11 screwed with the nut 12 arranged in the recess 17 or the nut 12 screwed with the bolt 11 arranged in the recess 17 is arranged on the side opposite to the terminal block 13 relative to the bus bar 10; and step (b), in which the bolt 11 or the nut 12 arranged on the side opposite to the terminal block 13 relative to the bus bar 10 is rotated so as to screw it into the nut 12 or the bolt 11 arranged in the recess 17, thereby connecting the bus bar 10 and the main terminal 7.

[0101] Therefore, when the bolt 11 or nut 12 located on the side of the busbar 10 opposite the terminal block 13 is tightened, the nut or bolt 11 located in the recess 17 can move toward the main terminal 7. Consequently, the main terminal 7 will displace until the bolt 11 or nut 12 located on the side of the busbar 10 opposite the terminal block 13 contacts the nut 12 or bolt 11 located in the recess 17. However, if the bolt 11 or nut 12 located on the side of the busbar 10 opposite the terminal block 13 contacts the nut 12 or bolt 11 located in the recess 17, the main terminal 7 will not displace further, and the nut 12 or bolt 11 located in the recess 17 will move toward the main terminal 7. In other words, the displacement of the main terminal 7 when the main terminal 7 and busbar 10 are connected using the bolt 11 and nut 12 is limited to the gap 18 between the bolt 11 and nut 12.

[0102] Thus, in the heat sink-integrated power module 202 , it is possible to reduce stress applied to the interface between the main terminal 7 and the molded portion 8 when the main terminal 7 and the bus bar 10 are connected using the bolts 11 and the nuts 12 .

[0103] In addition, the recess 17 includes a first recess 17a and a second recess 17b formed on the heat sink 16 side relative to the first recess 17a. The first recess 17a and the second recess 17b are connected. When viewed from the main terminal 7 side, the outline of the first recess 17a is larger than that of the second recess 17b.

[0104] Therefore, the second recess 17 b having a smaller outer dimension than the first recess 17 a functions as a relief portion for the shaft of the bolt 11 , thereby enabling the main terminal 7 and the bus bar 10 to be connected simply and productively.

[0105] The main terminals 7 extend in a first direction that is parallel to the base portion 14 of the heat sink 16 and are exposed from the mold portion 8 .

[0106] Therefore, the main terminals 7 do not need to be processed to form the terminals, which can improve productivity. Furthermore, since the main terminals 7 do not need to be processed to form the terminals, the main terminals 7 can be shortened. As the length of the main terminals 7 is shortened, the area of ​​the lead frame 3 including the main terminals 7 can be reduced accordingly. Alternatively, as the length of the main terminals 7 is shortened, the area of ​​the lead frame 3 including the main terminals 7 can be increased within the power module 202 while maintaining the same area.

[0107] In addition, the main terminal 7 has: a first parallel portion 7a, which is exposed from the molded portion 8 in a first direction parallel to the base portion 14 of the heat sink 16; a first vertical portion 7b, which extends from the first parallel portion 7a in a second direction in a vertical direction; and a second parallel portion 7c, which extends from the first vertical portion 7b in the first direction. The bus bar 10 is connected to the second parallel portion 7c of the main terminal 7.

[0108] This reduces the stress applied to the interface between the main terminal 7 and the molded portion 8 when connecting the main terminal 7 to the bus bar 10. Similarly, it reduces the stress applied to the interface between the main terminal 7 and the molded portion 8 when vibrations are generated during product use, thereby improving the product's vibration resistance.

[0109] Furthermore, at least one protrusion 19 is formed on the inner side of the recess 17. Therefore, when the terminal block 13 is manufactured, the nut 12 is arranged in the recess 17 of the terminal block 13. This allows the terminal block 13 to be transported without the nut 12 falling off. Therefore, the operation of placing the nut 12 in the recess 17 of the terminal block 13 when assembling the power module 202 is no longer necessary, thereby improving productivity.

[0110] In addition, a fitting portion 5a is provided on the other surface of the module base 5, and a fitted portion 14a that can be fitted with the fitting portion 5a is provided on the surface of the base portion 14 of the radiator 16 located on the module base 5 side. By fitting the fitting portion 5a and the fitted portion 14a, the module base 5 and the radiator 16 are integrated.

[0111] Therefore, integration of the process at room temperature can be achieved without increasing the size and complexity of the equipment, thereby improving productivity.

[0112] <Implementation Method 2>

[0113] Next, a power module 202 according to the second embodiment will be described. Figure 29 This is a cross-sectional view of a power module 202 according to the second embodiment. Figure 30 This is a cross-sectional view showing the connection between the main terminal 7 and the bus bar 10 included in the power module 202 according to the second embodiment, which is achieved by bolt fastening. Figure 31 1 is a plan view of the terminal block 13 , the nut 12 , and the nut retaining member 25 included in the power module 202 according to the second embodiment. Figure 32 This is a cross-sectional view showing the connection between main terminal 7 and bus bar 10 provided in power module 202 according to a modification of Embodiment 2, achieved by bolt fastening. In Embodiment 2, components identical to those described in Embodiment 1 are denoted by the same reference numerals, and their description is omitted.

[0114] like Figure 29As shown, in the second embodiment, compared with the case of the first embodiment, the power module 202 further includes a nut retaining member 25 (second structural member).

[0115] like Figure 30 and Figure 31 As shown, the nut anti-falling component 25 is formed into a "コ" shape when observed in cross section, and is installed in a manner that does not fall off in any direction while being able to move toward the main terminal 7 side and the heat sink 16 side relative to the terminal block 13. Specifically, the nut anti-falling component 25 is arranged between the main terminal 7 and the nut 12, and is installed by being engaged with the inside of the terminal block 13 below the recess 17 (heat sink 16 side). The two ends of the "コ" shape of the nut anti-falling component 25 face inward in a manner opposite to each other, and are engaged with the internal space 13b of the terminal block 13, which is located below the recess 17.

[0116] Here, the range of movement of the nut retaining member 25 toward the main terminal 7 must be within a range where the nut 12 does not fall off. When the main terminal 7 and the busbar 10 are connected by bolting, the nut 12 moves toward the main terminal 7. At this time, the nut 12 pushes against the nut retaining member 25, causing it to move toward the main terminal 7 along with the nut 12.

[0117] The material of the nut anti-falling component 25 can be any material such as resin or metal material. In addition, the nut anti-falling component 25 is not limited to Figure 30 For example, it is also possible to Figure 32 As shown, the U-shaped ends of the nut retaining member 25 face outward and upward in opposite directions. As described above, any structure may be used as long as the nut retaining member 25 and the nut 12 do not fall off the terminal block 13 and can move toward the main terminal 7 and the heat sink 16.

[0118] <Effect>

[0119] As described above, in embodiment 2 and its variations, the busbar 10 is connected to the first main surface of the main terminal 7 by means of bolts 11 and nuts 12, and the power module 202 also has a nut anti-falling component 25, which is arranged between the main terminal 7 and the nut 12 and is installed inside the terminal block 13 on the side closer to the heat sink 16 than the recess 17.

[0120] In addition, the manufacturing method of the power module 202 includes: step (a), in which a bolt 11 is arranged on the side opposite to the terminal block 13 relative to the bus bar 10 and is screwed into a nut 12 pre-arranged in the recess 17, while the bus bar 10 is arranged on the first main surface of the main terminal 7; and step (b), in which the bolt 11 arranged on the side opposite to the terminal block 13 relative to the bus bar 10 is rotated so as to be screwed into the nut 12 arranged in the recess 17, thereby connecting the bus bar 10 to the main terminal 7.

[0121] Therefore, the terminal block 13 can be transported while the nut 12 is prevented from falling off by the nut preventing member 25 . This eliminates the need to arrange the nut 12 on the terminal block 13 when assembling the power module 202 , thereby improving productivity.

[0122] <Implementation Method 3>

[0123] Next, a power module 202 according to the third embodiment will be described. Figure 33 This is a cross-sectional view of a power module 202 according to the third embodiment. Figure 34 This is a cross-sectional view showing a state of the main terminal 7 and the bus bar 10 included in the power module 202 according to the third embodiment before being fastened with bolts. Figure 35 1 is a cross-sectional view showing the connection between the main terminal 7 and the bus bar 10 included in the power module 202 according to the third embodiment, which is achieved by bolt fastening. Figure 36 1 is a plan view of the terminal block 13 , the nut 12 , and the nut retaining member 26 included in the power module 202 according to the third embodiment. Figure 37 This is a cross-sectional view showing a state before bolts are tightened on the main terminals 7 and the bus bar 10 included in a power module 202 according to a modification of the third embodiment. Figure 38 This is a cross-sectional view showing a state before bolts are tightened on main terminals 7 and busbar 10 included in power module 202 according to a modification of Embodiment 3. In Embodiment 3, components identical to those described in Embodiments 1 and 2 are denoted by the same reference numerals, and their description is omitted.

[0124] like Figure 33 As shown, in the third embodiment, compared with the case of the first embodiment, the power module 202 further includes a nut retaining member 26 (second structural member).

[0125] like Figures 33 to 36As shown, the nut anti-falling component 26 is formed into an L shape when viewed in cross section and is fixed to the terminal block 13. The rigidity of the nut anti-falling component 26 is smaller than that of the main terminal 7 and is flexible. The nut anti-falling component 26 can be made of any metal as long as it is a flexible metal. One end side of the nut anti-falling component 26 is arranged between the main terminal 7 and the nut 12, and the other end side of the nut anti-falling component 26 is fixed to the inside of the terminal block 13 below the recess 17 (heat sink 16 side).

[0126] With this structure, since the nuts 12 are arranged when the terminal block 13 is manufactured, the nut 12 can be transported without falling off, so there is no need to arrange the nuts 12 on the terminal block 13 when assembling the power module 202, thereby improving productivity. Figure 35 As shown, the flexible nut retaining member 26 deforms and the nut 12 moves toward the main terminal 7. Since the nut retaining member 26 fixed to the terminal block 13 is bolted together with the bus bar 10 and the main terminal 7, the vibration resistance of the assembled product is improved.

[0127] The nut anti-falling component 26 can be fixed to the terminal block 13 using any of the following methods, namely, insert molding the nut anti-falling component 26 when the terminal block 13 is molded, pressing the nut anti-falling component 26 after the terminal block 13 is molded, fixing the nut anti-falling component 26 to the terminal block 13 using bolts, or bonding the nut anti-falling component 26 to the terminal block 13 using bonding materials.

[0128] The nut anti-falling component 26 is not limited to Figure 34 and Figure 35 The structure shown, that is, the structure of covering the outer side of the nut 12, for example, can also be a structure of covering other sides of the nut 12, or can also be as shown in FIG. Figure 37 As shown, it is a structure fixed to the outer side surface of the terminal block 13.

[0129] In addition, if Figure 38 As shown, a U-shaped portion 27 may be provided at the bent portion of the nut anti-falling component 26, and the shape of the nut anti-falling component 26 may be freely designed. Figure 38 The shape shown in FIG. 2 can increase the flexibility of the nut anti-falling component 26. Figure 34 and Figure 35 In the figure, the nut anti-falling component 26 is fixed to the terminal block 13 at one location, but if the nut anti-falling component 26 itself is extended or a deformation portion such as a U-shaped structure is provided in the nut anti-falling component 26, the nut anti-falling component 26 can be deformed toward the main terminal 7 side, then the nut anti-falling component 26 can also be fixed to the terminal block 13 at two locations.

[0130] <Effect>

[0131] As described above, in embodiment 3 and its variations, the busbar 10 is connected to the first main surface of the main terminal 7 by means of the bolt 11 and the nut 12, and the power module 202 also has a nut anti-falling component 26, which is arranged between the main terminal 7 and the nut 12 and is installed inside the terminal block 13 on the side closer to the heat sink 16 than the recess 17.

[0132] In addition, the manufacturing method of the power module 202 includes: step (a), in which, when the bus bar 10 is arranged on the first main surface of the main terminal 7, a bolt 11 is arranged on the side opposite to the terminal block 13 relative to the bus bar 10 and is screwed into a nut 12 pre-arranged in the recess 17; and step (b), in which the bolt 11 arranged on the side opposite to the terminal block 13 relative to the bus bar 10 is rotated so as to be screwed into the nut 12 arranged in the recess 17, thereby connecting the bus bar 10 and the main terminal 7.

[0133] Therefore, the terminal block 13 can be transported while the nut 12 is prevented from falling off by the nut preventing member 26 . This eliminates the need to arrange the nut 12 on the terminal block 13 when assembling the power module 202 , thereby improving productivity.

[0134] <Implementation Method 4>

[0135] This embodiment applies the power module 202 of Embodiments 1 to 3 to a power conversion device. Application of the power module 202 of Embodiments 1 to 3 is not limited to a specific power conversion device. The following describes, as Embodiment 4, a case where the power module 202 of Embodiments 1 to 3 is applied to a three-phase inverter.

[0136] Figure 39 It is a block diagram showing the configuration of a power conversion system to which the power conversion device according to the present embodiment is applied.

[0137] Figure 39 The power conversion system shown in the figure consists of a power supply 100, a power conversion device 200, and a load 300. Power supply 100 is a DC power supply that supplies DC power to power conversion device 200. Power supply 100 can be composed of various power sources, such as a DC system, a solar cell, a battery, or a rectifier circuit or AC / DC converter connected to an AC system. Alternatively, power supply 100 can be composed of a DC / DC converter that converts DC power output from a DC system into a specified power.

[0138] The power conversion device 200 is a three-phase inverter connected between the power source 100 and the load 300, which converts the DC power supplied from the power source 100 into AC power and supplies the AC power to the load 300. Figure 39 As shown, the power conversion device 200 includes a main conversion circuit 201 that converts direct current into alternating current and outputs the converted alternating current, and a control circuit 203 that outputs a control signal for controlling the main conversion circuit 201 to the main conversion circuit 201 .

[0139] Load 300 is a three-phase motor driven by the AC power supplied from power converter 200. Load 300 is not limited to a specific application and may be a motor mounted on various electrical devices, for example, a motor for hybrid vehicles, electric vehicles, rail vehicles, elevators, or air conditioners.

[0140] The following describes the details of the power conversion device 200. The main conversion circuit 201 includes a switching element (not shown) and a freewheeling diode (not shown). By turning the switching element on and off, the DC power supplied from the power supply 100 is converted into AC power and supplied to the load 300. The specific circuit structure of the main conversion circuit 201 is diverse, but the main conversion circuit 201 involved in this embodiment is a two-level three-phase full-bridge circuit, which can be composed of 6 switching elements and 6 freewheeling diodes connected in anti-parallel with the switching elements. The power module 202 involved in any of the above-mentioned embodiments 1 to 3 is applied to at least any one of the switching elements and freewheeling diodes of the main conversion circuit 201. The 6 switching elements are connected in series in pairs to form upper and lower bridge arms, and each upper and lower bridge arm constitutes each phase (U phase, V phase, W phase) of the full-bridge circuit. Moreover, the output terminals of each upper and lower bridge arm, that is, the three output terminals of the main conversion circuit 201, are connected to the load 300.

[0141] In addition, the main conversion circuit 201 has a drive circuit (not shown) for driving each switching element, but the drive circuit can also be built into the power module 202, or it can be a structure with a drive circuit independent of the power module 202. The drive circuit generates a drive signal for driving the switching element of the main conversion circuit 201 and supplies it to the control electrode of the switching element of the main conversion circuit 201. Specifically, according to the control signal from the control circuit 203 described later, the drive signal for turning the switching element into the on state and the drive signal for turning the switching element into the off state are output to the control electrode of each switching element. When the switching element is maintained in the on state, the drive signal is a voltage signal greater than or equal to the threshold voltage of the switching element (on signal), and when the switching element is maintained in the off state, the drive signal is a voltage signal less than or equal to the threshold voltage of the switching element (off signal).

[0142] The control circuit 203 controls the switching elements of the main conversion circuit 201 so as to supply the desired power to the load 300. Specifically, the time (on-time) at which each switching element of the main conversion circuit 201 should be in the on state is calculated based on the power to be supplied to the load 300. For example, the main conversion circuit 201 can be controlled by PWM control that modulates the on-time of the switching element corresponding to the voltage to be output. In addition, a control instruction (control signal) is output to the drive circuit of the main conversion circuit 201 so that at each time point, an on signal is output to the switching element that should be in the on state, and an off signal is output to the switching element that should be in the off state. The drive circuit outputs the on signal or the off signal as a drive signal to the control electrode of each switching element in accordance with the control signal.

[0143] In the power conversion device according to this embodiment, since the power module 202 according to Embodiments 1 to 3 is used as a switching element and a freewheeling diode of the main conversion circuit 201 , productivity can be improved.

[0144] In this embodiment, the power module 202 according to Embodiments 1 to 3 is described as being applied to a two-level, three-phase inverter. However, the power module 202 according to Embodiments 1 to 3 is not limited to this application and can be applied to various power conversion devices. In this embodiment, a two-level power conversion device is used, but a three-level or multi-level power conversion device is also possible. When supplying power to a single-phase load, the power module 202 according to Embodiments 1 to 3 can also be applied to a single-phase inverter. Furthermore, when supplying power to a DC load, the power module 202 according to Embodiments 1 to 3 can also be applied to a DC / DC converter or an AC / DC converter.

[0145] In addition, the power conversion device using the power module 202 involved in embodiments 1 to 3 is not limited to the case where the above-mentioned load is an electric motor. For example, it can also be used as a power supply device for an electric discharge machine, a laser processing machine, an induction heating cooker, or a contactless power supply system, and can also be used as a power conditioner for a solar power generation system, a power storage system, etc.

[0146] While the present invention has been described in detail, the above description is in all aspects illustrative and not restrictive, and it should be understood that numerous modifications not shown are conceivable.

[0147] Furthermore, the various embodiments can be freely combined, and the various embodiments can be appropriately modified or omitted.

[0148] Hereinafter, various aspects of the present invention will be collectively described as supplementary notes.

[0149] (Note 1)

[0150] A power module comprising:

[0151] semiconductor components;

[0152] a frame having the semiconductor element mounted on one surface thereof;

[0153] a module base, which is configured with the frame on one side;

[0154] a main terminal, which is part of the frame;

[0155] a molding portion for encapsulating the semiconductor element, the frame, and the module base in a manner such that the main terminals are exposed;

[0156] a heat sink having a base portion and a plurality of heat dissipation fins, the base portion being integrated with the other surface of the module base exposed from the molded portion, the plurality of heat dissipation fins protruding toward the side of the base portion opposite to the module base;

[0157] an external terminal connected to the first main surface of the main terminal or the second main surface opposite to the first main surface by a bolt and a nut; and

[0158] a structural member fixed to the base portion of the heat sink and arranged between the main terminal or the external terminal and the base portion;

[0159] A recessed portion capable of accommodating the head of the nut or the bolt is formed on the main terminal side of the structural member.

[0160] The bolt screwed to the nut arranged in the recess or the nut screwed to the bolt arranged in the recess is arranged on the opposite side of the structural member with respect to the external terminal,

[0161] A rotation inhibiting portion is provided on an inner side surface of the recessed portion, and the rotation inhibiting portion inhibits rotation of the head portion of the nut or the bolt disposed in the recessed portion.

[0162] (Note 2)

[0163] The power module according to Supplementary Note 1, wherein:

[0164] The recess includes a first recess and a second recess formed on the heat sink side relative to the first recess.

[0165] The first recess is connected to the second recess,

[0166] When viewed from the main terminal side, the first recess has a larger outline than the second recess.

[0167] (Note 3)

[0168] The power module according to Supplementary Note 1 or 2, wherein:

[0169] The main terminal extends in a first direction that is parallel to the base portion of the heat sink and is exposed from the mold portion.

[0170] (Note 4)

[0171] The power module according to Supplementary Note 1 or 2, wherein:

[0172] The main terminal includes: a first parallel portion exposed from the mold portion in a first direction parallel to the base portion of the heat sink; a first vertical portion extending from the first parallel portion in a second direction perpendicular thereto; and a second parallel portion extending from the first vertical portion in the first direction.

[0173] The external terminal is connected to the second parallel portion of the main terminal.

[0174] (Note 5)

[0175] The power module according to any one of Supplementary Notes 1 to 4, wherein:

[0176] When viewed from the main terminal side, the recess, the nut, and the head of the bolt are formed in a hexagonal shape.

[0177] The minimum width of the recess is smaller than the maximum width of the head of the nut and the bolt,

[0178] The rotation restraining portion is configured based on a relationship between a minimum width of the recess and a maximum width of the head portion of the nut and the bolt.

[0179] (Note 6)

[0180] The power module according to any one of Supplementary Notes 1 to 5, wherein:

[0181] At least one convex portion is formed on the inner side surface of the concave portion.

[0182] (Note 7)

[0183] The power module according to any one of Supplementary Notes 1 to 6, wherein:

[0184] The external terminal is connected to the first main surface of the main terminal through the bolt and the nut.

[0185] The power module further includes a second structural member disposed between the main terminal and the nut and mounted on a portion of the interior of the structural member closer to the heat sink than the recess.

[0186] (Note 8)

[0187] The power module according to Supplementary Note 7, wherein:

[0188] The second structural member is made of metal.

[0189] (Note 9)

[0190] The power module according to any one of Supplementary Notes 1 to 8, wherein:

[0191] A fitting portion is provided on the other surface of the module base.

[0192] A fitted portion capable of fitting with the fitting portion is provided on a surface of the base portion of the heat sink located on the module base side.

[0193] The module base and the heat sink are integrated by the engagement of the engagement portion and the engaged portion.

[0194] (Note 10)

[0195] A method for manufacturing a power module, comprising manufacturing the power module described in any one of Supplementary Notes 1 to 6.

[0196] The manufacturing method has the following features:

[0197] Step (a) of placing the nut or the head of the bolt in the recessed portion with the external terminal disposed on the first main surface or the second main surface of the main terminal, and placing the bolt threadedly engaged with the nut disposed in the recessed portion or the nut threadedly engaged with the bolt disposed in the recessed portion on the side opposite to the structural member with respect to the external terminal; and

[0198] In step (b), the external terminal is connected to the main terminal by rotating the bolt or the nut disposed on the opposite side of the external terminal from the structural member to threadably engage the nut or the bolt disposed in the recess.

[0199] (Note 11)

[0200] A method for manufacturing a power module, comprising manufacturing the power module described in Supplement 7 or 8,

[0201] The manufacturing method has the following features:

[0202] Step (a) of arranging the bolt threadably engaged with the nut pre-arranged in the recess on the side opposite to the structural member with respect to the external terminal in a state where the external terminal is arranged on the first main surface of the main terminal; and

[0203] In step (b), the external terminal and the main terminal are connected by rotating the bolt disposed on the opposite side of the structural member with respect to the external terminal to threadably engage the bolt with the nut disposed in the recess.

[0204] (Note 12)

[0205] A power conversion device comprising:

[0206] A main conversion circuit comprising the power module according to any one of Supplementary Notes 1 to 9, wherein the main conversion circuit converts input power and outputs the converted power; and

[0207] A control circuit outputs a control signal for controlling the main conversion circuit to the main conversion circuit.

[0208] Description of the label

[0209] 1 Semiconductor chip, 3 Lead frame, 5 Module base, 5a Fitting portion, 7 Main terminal, 7a First parallel portion, 7b First vertical portion, 7c Second parallel portion, 8 Molded portion, 10 Bus bar, 11 Bolt, 12 Nut, 13 Terminal block, 14 Base portion, 14a Fitted portion, 15 Heat sink fin, 16 Heat sink, 17 Recess, 17a First recess, 17b Second recess, 19 Protrusion, 25, 26 Nut retaining member, 200 Power conversion device, 201 Main conversion circuit, 202 Power module, 203 Control circuit

Claims

1. A power module comprising: semiconductor components; a frame having the semiconductor element mounted on one surface thereof; a module base, which is configured with the frame on one side; a main terminal, which is part of the frame; a molding portion for encapsulating the semiconductor element, the frame, and the module base in a manner such that the main terminals are exposed; a heat sink having a base portion and a plurality of heat dissipation fins, the base portion being integrated with the other surface of the module base exposed from the molded portion, the plurality of heat dissipation fins protruding toward the side of the base portion opposite to the module base; an external terminal connected to the first main surface of the main terminal or the second main surface opposite to the first main surface by a bolt and a nut; and a structural member fixed to the base portion of the heat sink and arranged between the main terminal or the external terminal and the base portion; A recessed portion capable of accommodating the head of the nut or the bolt is formed on the main terminal side of the structural member. The bolt screwed to the nut arranged in the recess or the nut screwed to the bolt arranged in the recess is arranged on the opposite side of the structural member with respect to the external terminal, A rotation inhibiting portion is provided on an inner side surface of the recessed portion, and the rotation inhibiting portion inhibits rotation of the head portion of the nut or the bolt disposed in the recessed portion.

2. The power module according to claim 1, wherein: The recess includes a first recess and a second recess formed on the heat sink side relative to the first recess. The first recess is connected to the second recess, When viewed from the main terminal side, the first recess has a larger outline than the second recess.

3. The power module according to claim 1 or 2, wherein: The main terminal extends in a first direction that is parallel to the base portion of the heat sink and is exposed from the mold portion.

4. The power module according to claim 1 or 2, wherein: The main terminal includes: a first parallel portion exposed from the mold portion in a first direction parallel to the base portion of the heat sink; and a first vertical portion extending from the first parallel portion in a second direction vertical to the first parallel portion. and a second parallel portion extending from the first vertical portion in the first direction, The external terminal is connected to the second parallel portion of the main terminal.

5. The power module according to any one of claims 1 to 4, wherein: When viewed from the main terminal side, the recess, the nut, and the head of the bolt are formed in a hexagonal shape. The minimum width of the recess is smaller than the maximum width of the head of the nut and the bolt, The rotation restraining portion is configured based on a relationship between a minimum width of the recess and a maximum width of the head portion of the nut and the bolt.

6. The power module according to any one of claims 1 to 5, wherein: At least one convex portion is formed on the inner side surface of the concave portion.

7. The power module according to any one of claims 1 to 6, wherein: The external terminal is connected to the first main surface of the main terminal through the bolt and the nut. The power module further includes a second structural member disposed between the main terminal and the nut and mounted on a portion of the interior of the structural member closer to the heat sink than the recess.

8. The power module according to claim 7, wherein: The second structural member is made of metal.

9. The power module according to any one of claims 1 to 8, wherein: A fitting portion is provided on the other surface of the module base. A fitted portion capable of fitting with the fitting portion is provided on a surface of the base portion of the heat sink located on the module base side. The module base and the heat sink are integrated by the engagement of the engagement portion and the engaged portion.

10. A method for manufacturing a power module, comprising manufacturing the power module according to any one of claims 1 to 6. The manufacturing method has the following features: Step (a) of placing the nut or the head of the bolt in the recessed portion with the external terminal disposed on the first main surface or the second main surface of the main terminal, and placing the bolt threadedly engaged with the nut disposed in the recessed portion or the nut threadedly engaged with the bolt disposed in the recessed portion on the side opposite to the structural member with respect to the external terminal; and In step (b), the external terminal is connected to the main terminal by rotating the bolt or the nut disposed on the opposite side of the external terminal from the structural member to threadably engage the nut or the bolt disposed in the recess.

11. A method for manufacturing a power module, comprising manufacturing the power module according to claim 7 or 8, The manufacturing method has the following features: Step (a) of arranging the bolt threadably engaged with the nut pre-arranged in the recess on the side opposite to the structural member with respect to the external terminal in a state where the external terminal is arranged on the first main surface of the main terminal; and In step (b), the external terminal and the main terminal are connected by rotating the bolt disposed on the opposite side of the structural member with respect to the external terminal to threadably engage the bolt with the nut disposed in the recess.

12. A power conversion device comprising: A main conversion circuit comprising the power module according to any one of claims 1 to 9, wherein the main conversion circuit converts input power and outputs the converted power; and A control circuit outputs a control signal for controlling the main conversion circuit to the main conversion circuit.

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