Semiconductor power unit and method for manufacturing a semiconductor power unit

Abstract

The semiconductor power unit (1) comprises at least one power module (10) having a base plate (12) and a housing (18). The semiconductor power unit (1) further comprises a cooler unit (2) for cooling at least one power module (10) during operation. At least one power module (10) is coupled to the housing (8) of the cooler unit (2) by welding such that one or more welded joints (15) are formed between the housing (8) of the cooler unit (2), the at least one power module (10), and at least two of the coupling elements (11, 16, 17) for securing the at least one power module (10) to the housing (8) of the cooler unit (2).

Description

Technical Field

[0001] The present disclosure relates to a semiconductor power unit and a method for manufacturing a semiconductor power unit.

Background Art

[0002] Power modules are used, for example, in automotive inverters and require a cooler to dissipate heat during operation. To enable a stable and reliable setup of such a power unit, the power module is fixed to the cooler by screws or screw-in clamps.

Summary of the Invention

Problems to be Solved by the Invention

[0003] There is a need to provide a semiconductor power unit that enables a reliable and stable connection between a power module and a cooler for liquid cooling and contributes to reliable and effective heat dissipation during operation of the power module.

Means for Solving the Problems

[0004] Embodiments of the present disclosure relate to a semiconductor power unit that enables a stable and reliable connection and contributes to reliable heat dissipation. Embodiments of the present disclosure also relate to a corresponding manufacturing method for such a semiconductor power unit.

[0005] According to one embodiment, a semiconductor power unit comprises at least one power module having a base plate and a housing, and a cooler unit for cooling the at least one power module during operation. The at least one power module is joined to the housing of the cooler unit by welding such that one or more weld joints are formed between at least two of the housing of the cooler unit, the at least one power module, and a coupling element for fixing the at least one power module to the housing of the cooler unit.

[0006] By using the described configuration, a semiconductor power unit can be realized that enables a secure and stable coupling between the power module and the cooling unit for liquid cooling, and further contributes to reliable heat dissipation during power module operation. In particular, the semiconductor power unit is suitable for power modules used in high-voltage applications, such as at least 0.5kV.

[0007] Welded joints between the condenser unit housing, at least one power module, and / or coupling elements can be formed by resistance welding and / or arc welding and / or laser welding. There may be multiple separate weld spots, each forming its own welded joint. For example, one elongated welded joint may be present along substantially the entire length of the side of the power module. To contribute to a reliable and secure bond, there should be at least one welded joint on each of the opposing sides of the power module, securely fastening it to the condenser. Therefore, preferably, two or more welded joints are formed. According to one embodiment, the power module has a substantially rectangular or cuboidal shape, and for example, four welded joints may be formed near each edge of a cuboidal power module. Welding can be performed at several locations on each of the two opposing sides of the power module.

[0008] The housing of the cooler unit may include aluminum. In this regard, the housing may be made entirely or partially from aluminum, and may include aluminum in the form of bare aluminum and / or aluminum alloys. Alternatively or additionally, the housing may include copper and / or copper alloys. The housing may be made from any weldable material, or may include any weldable material.

[0009] The base plate may include aluminum or copper. In this regard, the base plate may be made entirely or partially from aluminum or copper, and the base plate may include aluminum or copper in the form of bare aluminum or copper and / or aluminum alloy or copper. The base plate of a power module may be made from any weldable material or may include any weldable material. For example, the base plate may be made from a composite material such as AlSiC or MgSiC, at least when clamped, when the base plate is not directly welded to the cooler. For example, the housing and base plate of a cooler unit may contain the same material or material composition. The aforementioned material choices may also apply to connecting elements which may contain any weldable material if intended for welding. For example, clamps, screws and / or bolts may also be made from the materials or compositions described above. Alternatively, the clamps, screws and / or bolts may be made from steel. Alternatively, the base plate, housing, clamps, screws and / or bolts may be made from materials made from zinc or Al-Zn alloy.

[0010] According to one embodiment of a semiconductor power unit, one or more welded joints are formed directly between the upper surface of the housing of the cooler unit and the lower surface of the base plate of the power module. Thus, the semiconductor power unit can be assembled without adding any connecting elements, and the power module and the cooler unit can be connected by welding. The upper surface of the housing has a surface that faces outward from the opposite bottom, such that the upper surface represents not only one or more uppermost parts of the housing, but also the inner upper surface of the bottom of a recess formed in the upper surface of the housing. To contribute to favorable welding conditions, the base plate of the power module may have one or more recesses at each of the locations of the one or more welded joints. Thus, the thermal influence required for welding is reduced by the thin-walled portion, which is associated with a smaller amount of material being melted in the base plate or clamp.

[0011] According to a further embodiment, the semiconductor power unit comprises coupling elements, including, for example, clamps, screws and / or bolts, for securing at least one power module to the housing of the cooler unit. For example, the power module is connected to the cooler unit using a screw-in clamp, and the connection is then reliably secured by welding and the formation of one or more welded joints. Alternatively, the coupling elements can be implemented as a clamp that simply holds the power module in place relative to the cooler unit. One or more welded joints can be formed directly between the upper surface of the housing of the cooler unit and the lower surface of the clamp. Furthermore, to have a beneficial effect on the welding process, the clamp may include one or more recesses at the respective locations of one or more welded joints.

[0012] If the coupling element further includes screws and / or bolts used to secure the power module to the cooler unit, the clamp includes one or more recesses at the respective locations of the one or more screws and / or bolts into which the screws and / or bolts are inserted. The clamp may include through recesses into which the screws or bolts are positioned. One or more welded joints can then be formed between the screws or bolts and the upper surface of the housing of the cooler unit, inside the through recesses of the clamp and / or on the upper surface of the clamp facing outward from the cooler unit. The screws or bolts can be fixed to their respective screw or bolt heads to secure their pre-assembled retaining positions. The welded joints can be formed between the screw heads and the upper surface of the clamp. Furthermore, it is possible to screw a base plate directly into the cooler, and one or more screws are fixed by welding in the same manner as described above. According to such embodiments, the base plate is configured to receive screws and has corresponding openings.

[0013] According to a further embodiment, the housing of the cooler unit may include one or more recesses that cooperate with one or more through recesses of one or more clamps, such that each screw or bolt extends through the through recess of the clamp into the corresponding recess of the housing of the cooler unit. One or more welded joints can then be formed inside the recess of the housing of the cooler unit between the screw or bolt and the housing of the cooler unit.

[0014] According to a further embodiment of the semiconductor power unit, screws and / or bolts are configured for welding, with each having a weld projection facing the housing of the cooler unit, such that a corresponding welded joint is formed by melting the weld projection. Such projections are also used to support the ignition of an electric arc in the case of arc welding or resistance welding. The screw or bolt head may also have such projections facing the upper surface of the clamp or base plate if the base plate is screwed directly into the cooler. During the welding process, the projections and portions of the screw or bolt are melted, respectively.

[0015] In connection with this disclosure, it is recognized that conventional power modules can be mechanically fastened to a power unit using clamp and screw-in mechanisms or direct screw-in of a base plate. In such conventional configurations, including screw-in clamps, the screw connections can result in torque loss, which can lead to loss of reliability due to thermal cycling or vibration, and therefore there may be a risk of coolant loss due to leakage during long-term operation.

[0016] The described structure of the semiconductor power unit and its fixed welded connections can counteract the aforementioned adverse effects. The use of the described method of securing the power module to the cooler unit can counteract loosening of screw or bolt connections caused by vibration, temperature cycles, and / or pressure cycles, which may have mechanical and thermal effects. As a result, where screws or bolts are used, the described arrangement configuration of the semiconductor power unit can help prevent the loosening of screws or bolts over time, which could lead to coolant leakage in an open cooler setup. In severe cases, replacement of the entire inverter may be necessary.

[0017] Furthermore, if screws or bolts are not used in the described arrangement configuration of the semiconductor power unit, bolt holes or threaded holes for screws are not required within the cooler structure. Therefore, according to such embodiments, it is possible to avoid the loss of space within the cooling structure, particularly inside the coolant channels, which is used to accept screws or bolts, potentially reducing the efficiency of the cooler by partially narrowing and / or blocking the flow of coolant, and increasing the total weight by the additional material required for the placement of threads or bolts.

[0018] According to further embodiments, the base plate of a power module and / or the housing and / or coupling elements of a cooler unit may include a coating that partially or completely covers the respective components. For example, such a coating may contain nickel and may cover the underside of the base plate and / or the inside of the cooler housing that come into contact with the coolant during operation of the power module and semiconductor power unit. The nickel coating may be configured to protect the base plate from corrosion due to contact with the coolant during operation. However, the nickel coating may also be used for other purposes.

[0019] Alternatively or additionally, there may be coatings containing silver and / or gold configured to provide predetermined bonding properties for joining adjacent components. Alternatively or additionally, to improve the formation of each welded joint, and thus the coupling of the power module to the housing of the cooler unit, a coating may be formed in the area where one or more welded joints are to be made. In addition to the above-mentioned possibilities of nickel, silver and / or gold, the coatings may be prepared from other materials suitable for providing protection and / or improved weld and bond properties and may be formed by an electroless or galvanic process or other applicable process.

[0020] The base plate of the power module may further comprise a bottom surface having a given surface structure that faces the internal flow path of the cooler unit and comes into contact with the coolant. Thus, a given cooling structure may be formed on the lower part of the base plate to provide a broad heat exchange surface between the power module and the coolant. The shape and / or orientation of the given surface structure may be configured to provide at least partially laminar or preferably turbulent flow of the coolant. Therefore, the surface structure can be designed to beneficially influence the flow behavior of the flowing coolant. In this regard, the pressure drop and flow rate of the coolant may also be taken into consideration when forming a given surface structure.

[0021] The surface structure of the bottom of the base plate may include one or more protrusions, realized by pin fin areas using pins having, for example, a cylindrical or conical shape, to increase the overall thermal efficiency, thereby giving an increased surface area to effectively transfer heat to the coolant. Additionally or alternatively, the surface structure may include ribs and / or skived structures and / or meandering channels. Alternatively, the bottom of the base plate may be formed without any particular structure on its bottom surface and thus may have a flat surface. Alternatively or additionally, cooling structures such as pins, ribs, or skived fins may be incorporated into a heat sink to which the flat bottom of the base plate can be attached.

[0022] The power module housing can be realized as a molded body forming an encapsulation with the electronic components inside, coupled to a base plate. The housing may also include a frame filled with a given resin or gel. The housing can realize the upper portion of the power module, and thus the base plate can realize the lower portion of the power module. The electronic components may include power semiconductor elements, integrated circuits, bare chips or packaged chips, such as controllers in an intelligent power module, and / or discrete elements. Chips or other elements are typically mounted on, for example, an insulating substrate, an insulating metal substrate, a PCB, or a lead frame. For example, an insulating substrate with an electrically insulating ceramic sheet may be mounted on the base plate, or, according to an alternative setup, an insulating metal substrate may incorporate the base plate as the bottom. The back or bottom surface of the base plate may be exposed for mounting and / or cooling purposes. Furthermore, the sides of the base plate may be exposed from the unit body for mounting, clamping, and / or welding of the power module to the housing of the cooling unit.

[0023] The housing of the cooler unit can be made from one or more parts and has internal passages for guiding the coolant. The housing has inlets and outlets that define the direction of coolant flow during operation. The housing further comprises one or more recesses configured to accommodate each power module. For example, the cooler unit has three recesses or one elongated recess for accommodating three power modules in a line with respect to the direction of coolant flow. One or more recesses are configured in geometric cooperation with the associated base plate or power module, and each power module is positioned inside and / or above its respective associated recess, and each is welded to the cooler housing, possibly by coupling elements such as screw-in or bolt-on clamps, or alternatively, directly welded without coupling elements.

[0024] In a further embodiment, the semiconductor power unit includes a sealing element for sealing the contact area between the power module and the cooler unit. The sealing element is located inside a sealing recess, for example, configured within the cooler housing, and contacts the upper surface of the housing on one side and the lower surface of the base plate on the other. The sealing element is preferably located inside a welded joint or closer to the flow path than the formed welded joint. Thus, the welded joint, in some cases interacting with a coupling element, forms a secure fixation of the power module to the cooler, and the sealing element securely seals the semiconductor power unit against undesirable coolant leakage. The sealing element and the corresponding sealing recess can completely surround each recess of the power module. The sealing element can be located inside the periphery formed by the welded joint. The sealing recess may be formed on the cooler housing and / or on the back or bottom of the base plate.

[0025] According to one embodiment, a method for manufacturing an embodiment of the described semiconductor power unit includes providing at least one power module having a base plate and a housing, and providing a cooler unit for cooling the at least one power module during operation. The method further includes coupling the at least one power module to the housing of the cooler unit by welding such that one or more weld joints are formed between at least two of the housing of the cooler unit, the at least one power module, and a coupling element for fixing the at least one power module to the housing of the cooler unit.

[0026] As a result of the described method being configured to manufacture an embodiment of the described semiconductor power unit, the described features and characteristics of the semiconductor power unit are also disclosed with respect to the manufacturing method, and vice versa.

[0027] According to one embodiment of the method, the step of coupling the at least one power module to the housing of the cooler unit by welding includes forming one or more weld joints by at least one of resistance welding, arc welding, and laser welding.

[0028] The step of coupling the at least one power module to the housing of the cooler unit by welding can further include pressing the at least one power module and the housing of the cooler unit together and directly forming one or more weld joints between the upper surface of the housing of the cooler unit and the lower surface of the base plate of the power module.

[0029] Alternatively or additionally, the method can include providing at least one clamp on the coupling element for fixing at least one power module to the housing of the cooler unit, and pressing the clamp against at least one power module, thereby pressing together at least one power module and the housing of the cooler unit. The method can then further include forming one or more weld joints between the housing of the cooler unit, at least one power module, and / or the clamp.

[0030] According to a further embodiment, the method includes providing at least one of a screw and a bolt on the coupling element, and fixing the clamp onto at least one power module and onto the housing of the cooler unit by attaching the screw and / or the bolt. The method then further includes forming one or more weld joints between the housing of the cooler unit, at least one power module, and / or the screw and / or the bolt.

[0031] The semiconductor power unit described can be manufactured, for example, using resistance welding or arc welding, particularly stud arc welding. The welding process is performed by operating on the upper side of the element joined to the cooler housing using a corresponding welding tool. Additionally, a holding device can be used to hold the mating part in a fixed position and, if necessary, apply a given pressure to one or both of the mating parts. Welding a bolt or screw to the metal base plate of the power module, for example by stud arc welding, contributes to fixing the screw by an additional welding step. The corresponding bolt or screw used for stud arc welding can be provided with a protrusion at the front tip or head to support the welding process by improving the initiation of the electric arc.

[0032] As a result of the above configuration in which the power module is fixed to the cooler by screw-in or bolt-on clamps, the fixing means can be fixed, and loosening of the screws or bolts can be prevented by additional welding steps, for example, by localized welding spots. The welding process can be applied by stud arc welding, using the projection of the screw tip or screw head, between the screw tip and the cooler housing inside the screw hole, or between the screw head and the upper surface of the clamp. As a result, the described arrangement configuration can reduce the risk of screws loosening, although the screw holes still consume space within the cooler structure.

[0033] Therefore, alternative methods refer to configurations that do not require screws or bolts, which can achieve a positive impact on the cooling efficiency of the cooler. For example, clamps used to hold one or more power modules in place may still exist, but without screws or bolts. On the one hand, the clamps are attached to the surface of the cooler housing by a retaining device such as a stamping element. The clamps can be welded directly to the surface of the cooler housing. The bottom surface of the clamps may have one or more projections to facilitate or improve the arc welding process. Alternatively or additionally, such projections may also be available on the bottom side of the base plate at the welding site.

[0034] Further alternative configurations can be achieved without clamps and other connecting elements. Direct welding of local portions of the power module base plate to the surface of the cooler housing can be formed. The corresponding welding process can be applied in particular to one or more open base plate portions in the peripheral region of the power module in question.

[0035] The described embodiments of the semiconductor power unit enable one or more of the following advantages due to the welded joints:

[0036] • Better securing of the power module to the cooler can be achieved. For example, the possibility of coolant leakage due to loosening screws at the customer site due to vibration can be prevented or the risk can be significantly reduced.

[0037] - Because it does not require space for screw or bolt holes within the cooler housing, which at least partially obstructs the flow of coolant, the design flexibility of the cooler and, in some cases, the cooling efficiency can be improved. In connection with this, the weight of the cooler can be reduced by using extra space for the cooling circuit.

[0038] • Depending on the selected configuration, screws and / or clamps are not required, which can lead to cost reductions and a reduction in the number of parts.

[0039] The semiconductor power unit described may be relevant to the field of e-mobility, but it can be applied to all types of power semiconductor modules that have a base plate mounted on a cooling housing.

[0040] Exemplary embodiments are described below with reference to schematic diagrams and reference numerals. The drawings are shown below. [Brief explanation of the drawing]

[0041] [Figure 1] This figure shows an embodiment of a semiconductor power unit in one of several different views. [Figure 2] This figure shows an embodiment of a semiconductor power unit in one of several different views. [Figure 3] This figure shows an embodiment of a semiconductor power unit in one of several different views. [Figure 4] This figure shows an embodiment of a semiconductor power unit in one of several different views. [Figure 5]This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 6] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 7] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 8] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 9] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 10] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 11] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 12] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 13] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 14] This figure shows an embodiment of manufacturing a semiconductor power unit in one of several different views. [Figure 15] This is a flowchart of a method for manufacturing one embodiment of a semiconductor power unit. [Modes for carrying out the invention]

[0042] The attached drawings are included to provide further understanding. Please understand that the embodiments shown in the drawings are illustrative and not necessarily drawn to actual size. The same reference numerals indicate elements or components having the same function. The descriptions of elements or components will not be repeated for each of the following drawings, insofar as they correspond to each other in relation to their function in the drawings. For clarity, elements may not be represented by corresponding reference numerals in all drawings.

[0043] Figure 1 shows a perspective view of one embodiment of a semiconductor power unit 1 having a cooler unit 2 and three power modules 10 arranged in a row. The three power modules 10 may also be referred to as a power package. Possible configurations and accessories for each power module 10 are shown in Figures 2 to 14. The cooler unit 2 is configured to liquid cool the power modules 10 (see also Figures 2 to 7). The cooler unit 2 has three recesses 22 corresponding to the three power modules 10 (see also Figure 3). The bottom side of each power module 10 is positioned to face or extend into the associated recess 22.

[0044] The cooler unit 1 further comprises a housing 8 that provides internal passages 6 for the coolant. The housing 8 further comprises inlets 3 and outlets 4 for the coolant so that the coolant can flow through the housing 8 during operation. Three recesses 22 penetrate the walls of the housing 8 to the passages 6 to accommodate each power module 10. The housing 8 can be assembled from, for example, two parts. Alternatively, the housing 8 can be manufactured as a single unit. According to the illustrated embodiment, the inlets 3 and outlets 4 belong to the lower part of the housing 8. The recesses 22 are configured in geometric coordination with the power modules 10.

[0045] Each power module 10 of the semiconductor power unit 1 comprises a base plate 12 and a housing 18 which can be formed as a molded body to provide encapsulation for the inside of the respective electronic device (see Figure 2). The base plate 12 may be formed as an insulating metal substrate consisting of a metal plate, an insulating resin layer, and circuit metallization. Furthermore, the power module 10 is provided with several terminals 19 that provide electrical interfaces such as main terminals and auxiliary terminals.

[0046] The power modules 10 or their respective base plates 12 are joined to the housing 8 of the cooler unit 2 by welding such that one or more welded joints 15 are formed between the housing 8 of the cooler unit, the power modules 10 and / or coupling elements for securing each power module 10 to the housing 8. Thus, the semiconductor power unit 1 may, but is not required to, have additional coupling elements (see Figures 1 to 14). If the semiconductor power unit 1 has additional coupling elements, these may include clamps 11 and / or screws 16 and / or bolts 17 for securing each power module 10 to the housing 8 of the cooler unit 2.

[0047] Therefore, one or more welded joints 15 can be formed directly between the upper surface 21 of the housing 8 of the cooler unit 2 and the lower surface 121 of the base plate 12 of the power module 10 (see Figures 9 to 14). Alternatively or additionally, in combination with additional connecting elements, one or more welded joints 15 can be formed directly between the upper surface 21 of the housing 8 of the cooler unit 2 and the lower surface 111 of the clamp 11 (see Figure 8) and / or the outer surfaces of the respective screws 16 or bolts 17 (see Figures 5 to 7). One or more welded joints 15 can be formed, for example, by resistance welding, arc welding and / or laser welding.

[0048] To contribute to a beneficial welding process by reducing the required thermal effects, one or both joining partners may include their respective recesses 112 or 122 (see Figure 8 or Figures 11-14). Recess 112 belongs to the clamp 11 and realizes a thin-walled portion of the clamp 11 that forms a joint region 5 prepared as an area for the welding process (see Figure 8). Recess 122 belongs to their respective base plates 12 and realizes a thin-walled portion of the exposed portion 14 of the base plates 12, thereby preparing the joint region 5 for the welding process (see Figures 11-14).

[0049] According to Figures 1 and 3, the power module 10 is mounted in an opening or recess 22 of the cooler unit 2 for liquid cooling by a clamp 11, and the clamp is secured to the cooler housing 8 by screws 16. The sealing element 7 is located inside the corresponding sealing recess 71 between the upper surface 21 of the cooler unit 2 and the lower surface 121 of the base plate 12 of the power module 10. Alternatively or additionally, the respective sealing recesses can be formed on the back or bottom side of the base plate 12. If there are additional sealing recesses on the back side of the base plate, both recesses can correspond to each other and accept one common sealing element 7. It is also possible to form two or more laterally separated sealing recesses. The clamp 11 applies force to the exposed base plate portion 14 in the peripheral region of the power module 10 (see also Figure 2). In this regard, terms such as “upper side,” “lower side,” “top,” “bottom,” and “side” are used to refer to the positions and / or orientations shown in the figures. The base plates 12 may have a cooling structure on their bottom surface in the form of a pin fin region that extends into the flow path 6 of the cooler unit 2, for example (see Figures 1, 3, and 4).

[0050] Figure 5 shows one embodiment of a semiconductor power unit 1 having a screw-in clamp 11 and a weld screw 16 in its respective head. The clamp 11 and / or the base plate 12 and / or the housing 8 may have recesses 51 that form screw holes for directly or indirectly securing the power module 10 to the cooler housing 8 by the screw 16. Alternatively or additionally, the fastening may be formed by bolts 17. When the screw 16 is used in a corresponding bonding recess 51 inside the base plate 12, the clamp 11 and / or the housing 8 have threads that interact with the screw 16 inserted into the screw recess 51. The screw 16 is secured to prevent loosening, for example, by welding the bottom surface of the screw head to the upper surface of the clamp 11 or the base plate 12. The arc welding process may be supported by one or more protrusions on the surface of the screw head near the clamp 11 or the base plate 12. Alternatively or additionally, laser welding, which generates a localized welding spot 15 on the screw head, may also be considered as a joining method. Welding may also be available inside the through recess 51 of the base plate or clamp 11. Alternatively or additionally, if laser welding is used, for example, a welded connection can be formed on the edge of the through recess adjacent to the mating part.

[0051] Alternatively or additionally, the screws 16 can be welded at their tips to the housing 8 of the cooler unit 2, as shown in Figure 6. The clamp 11 and / or base plate 12 are secured by the screws 16, each screw 16 being fixed in place by a welded connection between the screw tip or lower end of the screw 16 and the bottom surface of the screw hole forming a joint recess 51. For example, stud arc welding is typically facilitated or supported by a small projection pin on the end of the screw 16 that forms a screw projection 161 intended for welding. Such projections 161 can be pre-melted to form a corresponding welded joint 15. The projections 161 are used to generate a high electric field and thus support the ignition of the electric arc.

[0052] Figure 7 shows an alternative embodiment for material mating connections in which the power module 10 is coupled to the cooler unit 2. Clamps 11 are used to mount the power module 10 and are secured to the top surface 21 of the cooler unit by bolts 17 instead of screws. A weld connection is prepared between the bottom surface of each bolt 17 and the top surface 21 of the cooler housing, which forms the coupling region 5. Improvements to the welding process are achieved by recesses (not shown) in the bolts 17 at the location of the weld connection, which can reduce the required thermal influence by locally smaller metal thickness. Alternatively, the bolts 17 may be provided with projections 171 at their tips to facilitate or improve the welding process. Alternatively, the base plate 12 may be directly bolted to the cooler housing 8 without using clamps 11 for fixing.

[0053] Figure 8 shows a further embodiment relating to a material mating connection, connecting the power module 10 to the cooler unit 2. The welded joint 15 is prepared directly between a portion of the lower surface 111 of the clamp 11 and the upper surface 21 of the housing 8 of the cooler unit 2, without the need for screws or bolts. Improvements in the welding process and weld quality can be achieved, on the one hand, by one or more recesses 112 in the clamp 11 at the location of the welded joint to reduce the necessary thermal effects by locally smaller metal thickness, and therefore smaller amounts of material being melted. On the other hand, the back surface of the clamp 11 may have one or more protrusions to facilitate or improve the arc welding process. Alternatively or additionally, the upper surface 21 of the cooler housing 8 may have one or more protrusions.

[0054] The described configuration, using coupling elements in the form of clamps 11, screws 16, and / or bolts 17, makes it possible to securely fasten the power module 10 onto the cooler unit 2. This enables reliable sealing of the semiconductor power unit 1 and can counteract loosening of the screws 16 or bolts 17 due to vibration, temperature cycles, and / or pressure cycles that have mechanical and thermal effects on the corresponding connections. As a result, the described configuration eliminates the risk of coolant leakage in the cooler setup. In addition, screw holes forming recesses 51 for the screws 16 or bolts 17 within the cooler housing 8 can cause a loss of space within the cooling structure and locally reduce the width of the cooling channel 6, which can consequently reduce cooling efficiency by narrowing and / or partially blocking the flow of coolant (see Figure 4).

[0055] Accordingly, Figures 9 to 14 show further alternative embodiments for coupling the power module 10 to the cooler unit 2, relating to a material mating connection that does not require screws or bolts and corresponding coupling recesses. Even clamps for fixing are not required. The power module 10 is welded directly to the cooler unit 2 by welding the exposed portions 14 of their respective base plates 12 to the upper surface 21. For example, each power module 10 has two exposed base plate portions 14 in two opposing peripheral regions that are typically used for fixing by clamps. These exposed portions can be used to form welded joints 15, which are prepared in particular by resistance welding or arc welding. Alternatively or additionally, laser welding is also possible, particularly if recesses 112, 122 are available. If such recesses 112, 122 are sufficiently large, one or more welded joints 15 can be formed by ultrasonic welding.

[0056] Similar to the welded connection between the clamp and the cooler unit 2, improvements to the welding process are achieved, on the one hand, by recesses in the base plate 12 at the location of the welded connection that forms the joint area 5, thereby reducing the necessary thermal influence by locally smaller metal thickness. On the other hand, the back or bottom surface of the exposed base plate portion 14 may have one or more protrusions to facilitate or improve the arc welding process. Several welded connections using several recesses 122 can also be considered (see Figures 13 and 14). Figures 9 to 14 show different modifications for welding the exposed portion 14 of the base plate 12 to the top surface 21 of the cooler unit 2 with and without recesses 122. Thus, due to the fact that there are no screws or bolts used in such configurations, the corresponding joint recesses 51 are not required, and therefore the configurations described as shown in Figures 9 to 14 can contribute to improving the efficiency of the cooler unit 2, and the overall weight can be reduced, for example, because additional material can be saved for screw locations.

[0057] The steps of a corresponding manufacturing method for forming a semiconductor power unit 1 can follow the flowchart shown in Figure 15. In step S1, one or more power modules 10 having a base plate 12 and a housing 18 are provided.

[0058] In step S2, a cooler unit 2 is provided for cooling the power module 10 during operation.

[0059] In step S3, the power module 10 is mounted or positioned in the housing 8 of the cooler unit 2 within a corresponding recess 22 provided for it.

[0060] In step S4, the power module 10 and the housing 8 of the cooler unit 2 are joined together by welding such that one or more welded joints 15 are formed between the housing 8 of the cooler unit 2, the power module 10, and / or, if present, connecting elements in the form of clamps 11, screws 16 and / or bolts 17.

[0061] Therefore, a closed and securely sealed semiconductor power unit 1 can be realized. The embodiments shown in or described above in Figures 1 to 15 represent exemplary embodiments of the improved semiconductor power unit 1 and manufacturing method. Therefore, they do not constitute a complete list of all embodiments. Actual arrangement configurations and methods may differ from those shown, for example, with respect to the cooler unit. [Explanation of symbols]

[0062] Reference sign 1. Semiconductor Power Unit 2 Cooler Units 21 Top view of the cooling unit 22 Power module recess of the cooling unit 3. Inlet for the cooler unit 4. Outlet of the cooler unit 5 Combined area 51 Joint recess 6. Flow path of the cooler unit 7. Sealing element 71 Sealing recess of the cooler unit 8. Housing of the cooling unit 10 Power Modules 11 Clamp 111 Bottom surface of the clamp 112 Clamp recess 12 Power module base plate 121 Bottom surface of the base plate 122 Recess in the base plate 13. Cooling structure of power modules 14. Exposed base plate section 15. Welded joints 16 screws 161 Screw projection 17 volts 171 Bolt protrusion 18. Molded body / housing of power module 19 terminals S(i) Steps of a method for manufacturing a semiconductor power unit

Claims

1. A semiconductor power unit (1), A power module (10) having a base plate (12) and a housing (18), A cooler unit (2) for cooling the at least one power module (10) during operation and A semiconductor power unit (1) comprising, wherein the at least one power module (10) is coupled to the housing (8) of the cooler unit (2) by welding such that one or more welded joints (15) are formed between the housing (8) of the cooler unit (2), the at least one power module (10), and at least two coupling elements (11, 16, 17) for fixing the at least one power module (10) to the housing (8) of the cooler unit (2).

2. The semiconductor power unit (1) according to claim 1, wherein the welded joint (15) between the housing (8) of the cooler unit (2), the at least one power module (10), and / or the coupling elements (11, 16, 17) is formed by at least one of resistance welding, arc welding, and laser welding.

3. The semiconductor power unit (1) according to any one of the preceding claims, wherein the one or more welded joints (15) are directly formed between the upper surface (21) of the housing (8) of the cooler unit (2) and the lower surface (121) of the base plate (12) of the power module (10).

4. The semiconductor power unit (1) according to claim 3, wherein the base plate (12) of the power module (10) is provided with one or more recesses (122) at each of the one or more welded joints (15).

5. The semiconductor power unit (1) according to any one of the preceding claims, wherein the coupling element includes at least one of a screw (16), a bolt (17), and a clamp (11) for securing the at least one power module (10) to the housing (8) of the cooler unit (2).

6. The semiconductor power unit (1) according to claim 5, wherein the one or more welded joints (15) are directly formed between the upper surface (21) of the housing (8) of the cooler unit (2) and the lower surface (111) of the clamp (11).

7. The semiconductor power unit (1) according to claim 6, wherein the clamp (11) includes one or more recesses (112) at each of the one or more welded joints (15).

8. The semiconductor power unit (1) according to any one of claims 5 to 7, wherein the clamp (11) includes a through recess in which the screw (16) or bolt (17) is disposed, and the one or more welded joints (15) are formed between the screw (16) or bolt (17) and at least one of the upper surfaces (21) of the housing (8) of the cooler unit (2) on the inside of the through recess of the clamp (11) and the upper surface of the clamp (11) facing outward from the cooler unit (2).

9. The semiconductor power unit (1) according to claim 8, wherein the housing (8) of the cooler unit (2) includes a recess that coordinates with the through recess of the clamp (11) such that the screw (16) or bolt (17) extends through the through recess of the clamp (11) into the recess of the housing (8) of the cooler unit (2), and the one or more welded joints (15) are formed inside the recess of the housing (8) of the cooler unit (2) between the screw (16) or bolt (17) and the housing (8) of the cooler unit (2).

10. The semiconductor power unit (1) according to any one of claims 5 to 9, wherein the screw (16) and / or the bolt (17) are configured for welding such that the corresponding welded joint (15) is formed at least partially by melting the welded projections (161, 171), and each of the welded projections (161, 171) faces the housing (8) of the cooler unit (2).

11. The semiconductor power unit (1) according to claim 10, wherein each of the welding protrusions (161, 171) is formed on the head and / or tip of the screw (16) or the bolt (17).

12. The semiconductor power unit (1) according to any one of the preceding claims related to claim 5, wherein the screw (16) and / or bolt (11) is provided with one or more recesses (112) at each of the one or more welded joints (15).

13. A semiconductor power unit (1) according to any one of the preceding claims, comprising a sealing element (7) for sealing a contact area between the power module (10) and the cooler unit (2), wherein the sealing element (7) is positioned inside a sealing recess (71) and contacts the upper surface (21) of the housing (8) on one side and the lower surface (121) of the base plate (12) on the other side.

14. A method for manufacturing a semiconductor power unit (1), The steps include providing at least one power module (10) having a base plate (12) and a housing (18), The steps include providing a cooler unit (2) for cooling the at least one power module (10) during operation, The steps of welding the at least one power module (10) to the housing (8) of the cooler unit (2) such that one or more welded joints (15) are formed between the housing (8) of the cooler unit (2), the at least one power module (10), and at least two of the coupling elements (11, 16, 17) for fixing the at least one power module (10) to the housing (8) of the cooler unit (2), and Methods that include...

15. The step of joining the at least one power module (10) to the housing (8) of the cooler unit (2) by welding is, The method according to claim 14, comprising forming one or more welded joints (15) by at least one of resistance welding, arc welding, and laser welding.

16. The step of joining the at least one power module (10) to the housing (8) of the cooler unit (2) by welding is, Pressing both the at least one power module (10) and the housing (8) of the cooler unit (2), To directly form one or more welded joints (15) between the upper surface (21) of the housing (8) of the cooler unit (2) and the lower surface (121) of the base plate (12) of the power module (10) The method according to claim 14 or 15, including the method described in claim 14 or 15.

17. The steps include providing at least one clamp (11) on the coupling element for fixing at least one power module (10) to the housing (8) of the cooler unit (2), The steps include pressing the clamp (11) against the at least one power module (10), thereby pressing both the at least one power module (10) and the housing (8) of the cooler unit (2), The steps include forming one or more welded joints (15) between the housing (8), the at least one power module (10), and / or the clamp (11) of the cooler unit (2), and The method according to any one of claims 14 to 16, including the method described in any one of claims 14 to 16.

18. The steps include providing at least one of the screws (16) and bolts (17) to the connecting element, The steps include: securing the clamp (11) to the at least one power module (10) and the housing (8) of the cooler unit (2) by attaching the screws (16) and / or the bolts (17); The steps include forming the one or more welded joints (15) between the housing (8) of the cooler unit (2), the at least one power module (10), and / or the screws (16) and / or the bolts (17), The method according to claim 17, including the method described in claim 17.

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