Assembly comprising a plastic molded body and a plurality of load connection elements and power semiconductor device herewith

Abstract

Assembly (1) comprising a plastic molded body (2) and a plurality of load connection elements (4a, 4b, 4c) of a power semiconductor device, wherein each load connection element (4a, 4b, 4c) is designed as a planar metal molded body with a first and a second main surface (420, 422) opposite it and with a first and a second secondary surface (440, 442) opposite it, wherein these secondary surfaces connect the main surfaces (420, 422), and with a connection section (46), wherein the plastic molded body (2) forms a plurality of channels (20) and for this purpose has a bottom part body (22), a first and a second edge body (24, 26) and a separating body (28), wherein each load connection element (4a, 4b, 4c) is arranged at least with a substantial section in an associated channel (20), wherein an edge body (24, 26) of the channel (20) forms a Direction towards one main surface (420,422) of the immediately adjacent connecting element (4a,4c) has a directed recess (6,60,64,66).

Description

[0001] The invention describes an assembly comprising a plastic molded body and a plurality of load connection elements of a power semiconductor device, wherein each load connection element is designed as a planar metal molded body with a first and a second main surface opposite it, and with a first and a second secondary surface opposite it, wherein these secondary surfaces connect the main surfaces, and with a connection section, wherein the plastic molded body forms a plurality of grooves and for this purpose comprises a base body, a first and a second edge body, and a separating body, wherein each load connection element is arranged at least with a substantial portion in an associated groove. The invention further describes a power semiconductor device comprising such an assembly and a power electronic switching device.

[0002] DE 10 2018 112 552 A1 discloses an assembly and a power semiconductor device. The assembly comprises a plastic molded body and a plurality of load connection elements of the power semiconductor device, wherein each load connection element is designed as a planar metal molded body with a first and a second main surface opposite it, and with a first and a second secondary surface opposite it, wherein these secondary surfaces connect the main surfaces, and with a connection section, wherein the plastic molded body forms a plurality of grooves and for this purpose has a base body, a first and a second edge body and a separating body, wherein each load connection element is arranged in an associated groove with at least a substantial section without being materially bonded.that the first and second main surfaces and the first secondary surface face the inside of the channel and wherein the height of the separating body is greater than the width of the adjacent load connection element which has the smaller width.

[0003] EP 3 605 762 A1 discloses an arrangement with a busbar device and a converter housing, wherein the busbar device comprises a stack of at least two busbars and an electrically insulating insulating body enclosing the busbars in two insulating areas of the busbar device, wherein each busbar has two opposing base surfaces extending in the direction of current flow and side surfaces connecting the base surfaces and extending in the direction of current flow, wherein the busbar device has a temperature control area formed between the insulating areas in which the insulating body has an opening that exposes one of the side surfaces and a part of at least one of the base surfaces of a respective busbar, wherein the busbars in the temperature control area are thermally connected to the converter housing by a heat transfer medium.

[0004] DE 10 2008 012 703 A1 discloses a semiconductor device in which an outer resin housing is combined with a layered arrangement containing a semiconductor chip, an insulating circuit board on which the semiconductor chip is mounted, and a heat-dissipating metal support, wherein leg parts of external terminals arranged in a wall of the outer resin housing are drawn into the interior of the housing and contact wires connect the terminal leg parts to a conductor pattern of the insulating circuit board or the semiconductor chip, wherein the external terminals are pressed into terminal mounting holes pre-formed in the peripheral wall of the outer resin housing.

[0005] US Patent 5,424,579 A discloses a first composite substrate, consisting of an insulating substrate, a copper pattern, and a copper layer on opposing surfaces, mounted on a metal base plate. A second composite substrate and semiconductor chips are mounted on the first composite substrate and connected to each other by wire bonding. The current paths in the wires and in a copper pattern of the second composite substrate run antiparallel to the current paths in the corresponding sections of the first composite substrate. A semiconductor device is produced in which an increase in the switching frequency does not result in an increase in the surge voltage generated during switching on and off.

[0006] In light of the aforementioned circumstances, the invention is based on the objective of presenting an assembly for the mutual electrical isolation of a plurality of load connection elements of a power semiconductor device and such a power semiconductor device itself, wherein the heat dissipation from the assembly is improved compared to the prior art.

[0007] This problem is solved according to the invention by an assembly comprising a plastic molded body and a plurality of load connection elements of a power semiconductor device, wherein the respective load connection element is designed as a planar metal molded body with a first and a second main surface opposite it and with a first and a second secondary surface opposite it, wherein these secondary surfaces connect the main surfaces, and with a connection section, wherein the plastic molded body forms a plurality of grooves and for this purpose has a bottom part body, a first and a second edge body and a separating body, wherein a load connection element is arranged at least with a substantial section in an associated groove, wherein an edge body of the groove has a recess directed towards a main surface of the immediately adjacent connection element.

[0008] The load connection elements can be designed and configured to carry DC or AC potentials and can be intended for power semiconductor devices, preferably designed as two-level, three-level or multi-level converters.

[0009] In this case, the depression can preferably be designed as a continuous depression.

[0010] It can generally be advantageous if the recess is located in a section of the channel adjacent to a subsection of the section of the immediately adjacent connection element that experiences the greatest heat during operation. In this case, it can be advantageous if the main surfaces of the load connection element immediately adjacent to the recess, facing the recess, are flush with the inside of the associated channel. Alternatively, it can be advantageous if the main surfaces of the load connection element immediately adjacent to the recess, facing the recess, are spaced apart on the inside of the associated channel.

[0011] Furthermore, it can be advantageous if the recess is arranged in a section of the channel adjacent to a subsection of the section of the indirectly adjacent connection element, which experiences its greatest heating during operation. This prevents the directly adjacent connection element from being cooled.

[0012] It may be preferred if a separating body has a continuous or a non-continuous depression or both.

[0013] Alternatively, it may be preferred if the plastic molded body is made of a material from the elastomer group, preferably silicone rubbers, in particular thermally stabilized silicone rubber, especially with a Shore A hardness between 30 and 90, preferably between 55 and 70. Alternatively, it may also be preferred if the plastic molded body is made of a material from the polyolefin group, in particular modified PTFEs, preferably filled PTFEs, in particular silicate-filled PTFE.

[0014] It is particularly advantageous if the height of the separating body is at least as large as the width of the adjacent load connection element that has the greater width.

[0015] It is particularly advantageous if one or both of the edge bodies or the separating body have a lifting device designed to limit movement of the load connection element arranged in an associated channel out of the channel, i.e., away from the base body. Naturally, more than one edge body or more than one separating body can also have such lifting devices.

[0016] Additionally, one of the load connection elements may have a bend, which is preferably arranged in a channel.

[0017] The above-mentioned problem is further solved according to the invention by a power semiconductor device with an assembly comprising a plastic molded body and a plurality of load connection elements according to one of the preceding claims and with a power electronic switching device, wherein the assembly is arranged in a receptacle of a housing with a cooling device of the power semiconductor device and wherein the assembly is thermally conductively connected to a cooling surface in the area of ​​the recess by means of a heat-conducting material.

[0018] It is preferred if the housing or cooling device has the cooling surface.

[0019] Preferably, the cooling device is designed as an air or liquid cooling device.

[0020] It may be particularly preferred if the heat-conducting material is designed as an electrically insulating potting compound, especially with heat-conducting, particularly ceramic, particles.

[0021] Of course, unless explicitly or per se excluded or contrary to the idea of ​​the invention, the features or groups of features mentioned in the singular, for example the respective connection sections and in particular the recess, may be present multiple times in the assembly or power semiconductor device according to the invention.

[0022] It is understood that the various embodiments of the invention, regardless of whether they are mentioned in connection with the assembly or with the power semiconductor device, can be implemented individually or in any combination to achieve improvements. In particular, the features mentioned and explained above and below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention.

[0023] Further explanations of the invention, advantageous details and features, will become apparent from the following description of the invention contained in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. 8 schematically illustrated embodiments of the invention, or of respective parts thereof. Fig. Figure 1 shows a cross-section through a first assembly according to the invention. Fig. Figure 2 shows a cross-section through a second assembly according to the invention. Fig. Figure 3 shows the operation of the second assembly. Fig. Figure 4 shows a plastic molded body of a third assembly according to the invention. Fig. 5 and Fig. Figure 6 shows this third assembly according to the invention. Fig. Figure 7 shows a power semiconductor device according to the invention with the third assembly according to the invention. Fig. Figure 8 shows a cross-section through a fourth assembly according to the invention.

[0024] Fig. Figure 1 shows a cross-sectional view of a first assembly 1 according to the invention. A plastic molded body 2, made of silicone rubber, more precisely a cross-linked liquid silicone rubber (LSR) with a Shore A hardness between 55 and 60, is shown. In this embodiment, the plastic molded body 2 forms three channels 20 by having a first and a second edge body 24, 26 extending vertically from each side of a base body 220, and two separating bodies 28 also extending vertically and with the same height 280 between these edge bodies 24, 26. The height 280 is measured from the inside 200 of the channel 20 from the base body 220 to the end of the edge body 24, 26 or separating body 28. Furthermore, purely by way of example and without limiting the generality, the second edge body 26 has a stop element shaped as a nose 32. This nose 32 protrudes into the interior of the groove 20.

[0025] In each channel 20, a load connection element 4, made of a material typical for the industry, is arranged. This element is designed as a planar metal body with a first main surface 420, 422 and a second main surface 420, 422 opposite the first. The metal body also has a first secondary surface 440, 442 opposite the first, with each of these secondary surfaces connecting the main surfaces. The load connection element 4 thus has a rectangular cross-section.

[0026] Each load connection element 4 is arranged in an associated channel 20 and is not materially bonded there. The main surfaces 420, 422 each face an edge body 24, 26 or separating body 28, while the first secondary surface 440 faces the base body 220. The respective load connection element 4 thus has three sides of its inner surface 200 facing the channel 20. The lug 32 of the second edge body 26 ensures a positive locking fixation of the load connection element 4 arranged in the associated channel 20. Alternatively, or additionally, the load connection elements 4 can be force-fitted in their respective associated channels 20 by making the channel 20 slightly narrower during the production of the plastic molded body 2 compared to the extension of the load connection element 4 from the first to the second main surface 420, 422.

[0027] In this first embodiment of the assembly 1 according to the invention, all load connection elements 4 have the same width 480, i.e., the same extent between the secondary surfaces 440, 442. Also according to the invention, the height 280 of each separating body 28 is greater than the width 480 of the two adjacent load connection elements 4.

[0028] To cool the right-hand terminal element 4c, the adjacent second edge body 26 has a recess 6 directed towards a main surface 422 of the immediately adjacent terminal element 4c facing the second edge body 26. This recess 6 is designed as a non-through recess 60. However, the remaining wall thickness is chosen to be minimal in order to ensure sufficient electrical insulation from an adjacent body (not shown).

[0029] The main surfaces 420, 422 of the immediately adjacent load connection element 4c, facing this recess 6, lie flush against the inside of the associated channel 20. A heat-conducting material (not shown) arranged outside the plastic molded body 2 thus allows the connection element 4c, in particular the section that experiences its highest heat output during operation, to be cooled very effectively without compromising electrical insulation.

[0030] The same configuration of assembly 1 can also serve to cool an indirectly adjacent connection element 4b, which experiences its greatest heat generation during operation. In this case, the immediately adjacent connection element 4c acts as an additional heat conductor through which the heat is dissipated from the indirectly adjacent connection element 4b.

[0031] Fig. Figure 2 shows a cross-section through a second assembly according to the invention. Fig. Figure 3 shows the operation of the second assembly. The basic design of the plastic molded body 2 and the load connection elements 4 is identical to those according to [reference to figure]. Fig. 1. In contrast, the middle load connection element 4b has a smaller width 480 but a greater thickness. According to the invention, the height 280 of the left separating body 28 is greater than the width 480 of the adjacent load connection element 4b, here the middle one, which has the smaller width. Furthermore, the height 280 of the left separating body 28 is even greater than the width 480 of the adjacent load connection element 4a, here the left one, which has the larger width 480. This configuration is preferred over the minimum requirement.

[0032] To cool the right-hand connection element 4c, the adjacent edge body 26 has a recess 6 directed towards a main surface 422 of the immediately adjacent connection element 4c facing the edge body 26. This recess 6 is designed as a continuous recess 66, so that the plastic molded body 2 no longer has an electrically insulating effect here.

[0033] The main surfaces 420, 422 of the immediately adjacent load connection element 4c, facing this recess 6, are spaced apart from the inside of the associated channel 20. As shown in Fig. As shown in Figure 3, a heat-conducting material 600 can thus penetrate through this depression 6 into the channel 20 without necessarily completely flooding it, neither in terms of its height nor its length.

[0034] The thermally conductive material 600 is designed here as an electrically insulating potting compound filled with thermally conductive ceramic particles. This thermally conductive material 600 will very effectively cool the connection element 4c, in particular the section that experiences its greatest heating during operation, by transferring heat to a cooling surface 84. This cooling surface 84 is, without limitation of generality, part of a liquid cooling system for a power semiconductor device 8.

[0035] This configuration of assembly 1 can also serve to dissipate heat from an indirectly adjacent connection element 4b.

[0036] Fig. Figure 4 shows a plastic molded body 2 of a third assembly 1 according to the invention, while Fig. 5 and Fig. 6 this third assembly 1 according to the invention in two views, Fig. Figure 6 shows a sectional view. The plastic molded body 2 has three channels 20 of different lengths but the same height. The middle channel 20, in particular, has a right-angled curve. The design of the plastic molded body 2, made of silicone rubber, allows for a high degree of flexibility in the shape of the channels 20.

[0037] Also shown is a continuous depression 64 of a first boundary body 24. The second boundary body 26 has, as in Fig. Figure 5 also shows a corresponding continuous recess 66. The basic function of the respective recesses 6, 64, and 66 has already been described above. Fig. Figure 6 shows both depressions 64,66 in cross-section through the assembly.

[0038] Fig. Figure 5 shows three load connection elements 4 arranged in associated grooves 20 of the plastic molded body 2. These load connection elements 4 are designed as described above as flat metal molded bodies with two main and two secondary surfaces and each has a connection section 46 designed as a screw recess. A second tab 50 per load connection element 4 serves as a further connection section.

[0039] Each load connection element 4 is arranged in a corresponding groove 20 of the plastic molded body 2 over a substantial section, here over 80% of its length. All three load connection elements 4 also have a right-angled offset 48, which is arranged in the curve of the corresponding groove 20.

[0040] Fig. Figure 7 shows a three-dimensional sectional view of a power semiconductor device 8 according to the invention, comprising the third assembly 1 according to the invention. A liquid cooling device 80 of the power semiconductor device 8 is shown, with two recesses 800 and 802. The aforementioned assembly 1 is arranged in one recess 800, while a power electronic three-level switching device is arranged in another recess 802 (not shown here). The cooling surfaces 84 are the side walls of the recess 800 of the assembly 1.

[0041] For the sake of clarity, a representation of the AC voltage connections and other components has been omitted here.

[0042] Fig. Figure 8 shows a cross-section through a fourth assembly 1 according to the invention, which differs from that according to the Fig. 2 and Fig.3 has an additional recess 6, which is arranged in a separating body 28 and is designed as a continuous recess 68. Thus, not only the channel containing the heat-conducting material 600 can be filled, but also the adjacent channel 20 across this additional recess 6. This further improves heat dissipation from the load connection elements 4b, 4c. This applies particularly to those in direct contact with the heat-conducting material 600.

Claims

[1] Assembly (1) comprising a plastic molded body (2) and a plurality of load connection elements (4a, 4b, 4c) of a power semiconductor device, wherein each load connection element (4a, 4b, 4c) is designed as a planar metal molded body with a first and a second main surface (420, 422) opposite it and with a first and a second secondary surface (440, 442) opposite it, wherein these secondary surfaces connect the main surfaces (420, 422), and with a connection section (46), wherein the plastic molded body (2) forms a plurality of channels (20) and for this purpose has a bottom part body (22), a first and a second edge body (24, 26) and a separating body (28), wherein each load connection element (4a, 4b, 4c) is arranged at least with a substantial section in an associated channel (20), wherein an edge body (24, 26) of the channel (20) one in the direction of the main surface (420,422) of the immediately adjacent connecting element (4a,4c) has a directed recess (6,60,64,66). [2] Assembly according to claim 1, wherein the recess (6) is formed as a continuous recess (64,66). [3] Assembly according to one of the preceding claims, wherein the recess (6) is arranged in a section of the channel (20) which is adjacent to a subsection of that section of the immediately adjacent connecting element (4a,4c) which experiences its strongest heating during operation. [4] Assembly according to one of the preceding claims, wherein the recess (6) is arranged in a section of the channel (20) which is adjacent to a subsection of the section of the indirectly adjacent connecting element (4b) which experiences its strongest heating there during operation. [5] Assembly according to claims 1 to 4, wherein the main surfaces (420,422) facing the recess (6) of the load connection element arranged immediately adjacent to the recess (64,66) are flush with the inside of the associated channel (20). [6] Assembly according to claims 1 to 4, wherein the main surfaces (420, 422) facing the recess (6) of the load connection element arranged immediately adjacent to the recess (64, 66) are spaced apart on the inside of the associated channel (20). [7] Assembly according to one of the preceding claims, wherein a separating body (28) has a continuous recess (68). [8] Assembly according to one of the preceding claims, wherein a separating body (28) has a non-through depression (60). [9] Assembly according to one of the preceding claims, wherein the plastic molded body (2) is made of a material from the material group of elastomers, preferably silicone rubbers, in particular thermally stabilized silicone rubber, in particular with a Shore A hardness between 30 and 90, preferably between 55 and 70, or of a material from the material group of polyolefins, in particular modified PTFEs, preferably filled PTFEs, in particular silicate-filled PTFE. [10] Assembly according to one of the preceding claims, wherein the height (280) of the separating body (28) is at least as large as the width (480) of the adjacent load connection element (4) which has the larger width. [11] Assembly according to one of the preceding claims, wherein one of the edge bodies (24, 26) or the separating body (28) has a stop means (32) which is designed to limit a movement of the load connection element (4) arranged in an associated trough (20) out of the trough (4) and away from the bottom body (22). [12] Assembly according to one of the preceding claims, wherein one of the load connection elements (4) has a bend (48) preferably arranged in the channel (2). [13] Power semiconductor device (8) comprising an assembly (1) with a plastic molded body (2) and a plurality of load connection elements (4) according to one of the preceding claims and with a power electronic switching device, wherein the assembly (1) is arranged in a receptacle (800) of a housing with a cooling device (80) of the power semiconductor device (8) and wherein the assembly (1) is thermally connected in the area of ​​the recess (6) to a cooling surface (84) by means of a heat-conducting material (600). [14] Power semiconductor device according to claim 13, wherein the housing or cooling device (80) has the cooling surface (84). [15] Power semiconductor device according to claim 13 or 14, wherein the cooling device (80) is designed as an air or liquid cooling device. [16] Power semiconductor device according to claims 13 to 15, wherein the heat-conducting material (600) is designed as an electrically insulating potting compound, in particular with heat-conducting, in particular ceramic, particles.

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