Direct cooling of power converters using stamped plates

Abstract

The present invention relates to a converter (10) comprising a semiconductor module (11) having a base plate (12) and a cooling housing (13), the cooling housing (13) including a receiving plate (14) and a cover (15), the receiving plate (14) having at least one opening (16), the receiving plate (14) being connected to the base plate (12) of the semiconductor module (11) around the opening (16), the cover (15) being connected to the receiving plate (14) around the opening (16) along a sealed path, either the receiving plate (14) or the cover (15) being designed as a stamped or deep-drawn plate. The present invention also relates to a method for manufacturing a converter (10) according to the above characteristics.

Description

[Technical field]

[0001] The subject of the invention is a converter comprising at least one semiconductor module having a base plate and a cooling housing. [Background technology]

[0002] The rapid increase in electric vehicles is creating great pressure on the power and cost of power semiconductor modules used in electric drivetrains. For semiconductor modules, this is especially accompanied by continuously increasing operating temperatures and increasing power densities.

[0003] As a way to raise the permissible operating temperature to a higher level, it is conceivable to replace the conventional casting of the top surface of the semiconductor module by injection molding. In this case, the module formed by injection molding can have a base plate that is held in the molding material. For optimal cooling, the cooling structure can be formed so as to be directly integrated with the base plate, the cooling structure being in contact with the cooling liquid.

[0004] A semiconductor module or half-bridge module generally contains two functional switching contacts. To provide a three-phase converter, it is necessary to combine three semiconductor modules. Therefore, a cooler has an inlet port and an outlet port, and the cooling fluid led through the cooler must pass through the cooling structure of all three semiconductor modules.

[0005] It would be conceivable to arrange all six functional switching contacts on one large plate. However, in the case of compression molding, there is generally a limit to the maximum volume that the molding compound can have, which is larger than the combined volume of the three semiconductor modules. If all untested semiconductor chips were further placed on one base plate, this would result in a significant reduction in the production yield due to chip or connection defects. For high production volumes, it is therefore important that the half-bridge modules are manufactured and tested individually before being assembled to form the converter.

[0006] From EP 0 831 684 A2 there is known a packaging for power electronics, which comprises a deep-drawn, hat-shaped cover and a flat sealed base, which are interconnected by folding over a downwardly depending circumferential edge of the cover in order to seal the electronic printed circuit board. The cover may have an L-shaped circumferential edge, with a first portion projecting radially outward and a second portion depending downward. Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to provide a converter which allows a reliable, compact and economical arrangement of closely spaced different half-bridge modules, in particular a six-port configuration. [Means for solving the problem]

[0008] This object is achieved by a converter having the features of claim 1 and by a method having the features of claim 9. Advantageous developments and embodiments are the subject of the description and of the drawings.

[0009] The subject of the invention is a converter comprising at least one semiconductor module having a base plate and a cooling housing.

[0010] According to the invention, the cooling housing comprises a receiving plate and a cover, the receiving plate having at least one opening, the receiving plate being connected to a base plate of the semiconductor module around the at least one opening and the cover being connected to the receiving plate along a connection area around the at least one opening, and either the receiving plate or the cover being designed as a stamped or deep-drawn plate.

[0011] Generally, a semiconductor module includes a substrate and a base plate, and the base plate is disposed on the substrate using a molding material. Typically, a cooling structure is disposed on the base plate. Generally, the base plate is made of aluminum-clad copper, aluminum, aluminum alloy, or AlSiC (aluminum silicon carbide).

[0012] The receiving plate is designed as a frame and generally has at least one opening configured to receive at least a part of the base plate. The opening is generally configured to receive the cooling structure of the base plate. The opening is generally designed to be rectangular. The opening may optionally have rounded corners. The base plate has a connection area formed around each opening of the base plate. The base plate is welded to the receiving plate in this connection area. This provides the advantage that the semiconductor module can be arranged so that it can be tested after welding. Welding the semiconductor module, and in particular the base plate, to the receiving plate results in the cooling structure of the semiconductor module / half-bridge module not being able to extend to the boundary of the cooling channel, because the overlapping area of ​​the semiconductor receiving plate and the base plate must be accessible to the welding device. For this reason, a bypass blocker may be optionally inserted into the cooling housing.

[0013] The cover is configured to form a cooling housing or a cooling passage together with the receiving plate. In this case, the cover is generally welded onto the receiving plate. When the cover is welded on, the result is a leak-tight cooling passage or a leak-tight cooling housing configured to conduct the cooling liquid. The cover may have a curved design, and the curvature can be designed so that the cover is curved towards the base plate, or towards the opposite side to the base plate, or parallel to the base plate. In the case of a configuration of the cover that is curved towards the base plate, the rounded edge of the cover does not contact the base plate at a right angle, so that instead of a T-weld in which two plates arranged at a right angle to each other are welded together, flange welding can be performed. Flange welding provides the advantage that the flange welds can withstand a larger pressure, making the welding procedure less sensitive to mechanical tolerances and increasing the robustness and leak resistance of the sealed cooling housing. A further advantage is that the receiving plate and the cover can be manufactured by deep drawing or stamping. In this case, stamping is a special form of deep drawing where the depth is not very large.

[0014] The stamping design of the receiving plate further offers the advantage that the manufacturing costs can be minimized while at the same time ensuring good weldability and leak resistance, in particular in comparison with parts made from die-cast aluminum. Thus, the invention is particularly suitable for the direct integration of water-cooled, compression-molded semiconductor modules in traction inverters for electric vehicles.

[0015] In some embodiments, the base plate, the containment plate, and the cover are configured to form a cooling housing or a cooling passage for a cooling fluid. The base plate, the containment plate, and the cover are typically connected to one another such that a space is formed therebetween that is configured to contain the cooling structure of the base plate. The cooling passage or cooling housing is configured to allow a cooling fluid to pass therethrough. The cooling fluid may be water, a mixture of water and glycol, or another coolant.

[0016] The cover is configured to be connectable to the receiving plate. The cover is connected to the receiving plate and together with the receiving plate forms a cooling housing or a cooling channel. The required height (volume) of the cooling housing or cooling channel, in particular the required height of the cooling structure or the cooling channel to receive the cooling structure, is realized by stamping or deep drawing either or both of the receiving plate and / or the cover.

[0017] The cover thus optionally has stamped or deep drawn portions. For example, the stamped portions can be designed to be curved or trough shaped. The receiving plate thus optionally has stamped or deep drawn portions. For example, the stamped portions can be designed to be curved or trough shaped.

[0018] In one development, the base plate has a cooling structure to which the cooling liquid is exposed in the openings of the receiving plate. The cooling structure can be designed, for example, in the form of cooling ribs or cooling pins. The cooling structure is generally formed adjacent to the semiconductor chip on the base plate.

[0019] In yet another development, either the receiving plate or the cover is designed to be trough-shaped, the depth of the trough-shaped stamped portion providing the required height for the cooling channels and the required height for receiving the cooling structures, in particular the cooling ribs.

[0020] In an embodiment, the cover has an inlet port and an outlet port for fluidically connecting the semiconductor modules. The cooling liquid can be introduced into the cooling housing through the inlet port. The cooling liquid generally flows from the inlet port to the outlet port. In this case, the cooling liquid flows through at least one of the cooling structures of the semiconductor modules arranged on the plate. Each of the inlet and outlet ports can be designed as a separate part that can be provided on the cover in a separate process. For example, the inlet and outlet ports can be welded onto the cover. Alternatively, the inlet and outlet ports can be designed as recesses in the cover. The inlet and outlet ports are typically configured to be connectable with a connector having an O-ring or a seal.

[0021] In one embodiment, the receiving plate is connected to the base plate by welding, in particular laser welding, and / or the cover is connected to the receiving plate by welding, in particular CMT (cold metal transfer) welding. Alternatively, the receiving plate is connected to the base plate by laser metal deposition (LMD). The receiving plate is generally connected to the base plate in a connection area formed circumferentially around the opening of the receiving plate.

[0022] In one development, the receiving plate and the base plate are made from aluminum or an aluminum alloy. Alternatively, the receiving plate is made from copper clad with aluminum.

[0023] In one embodiment, the containment plate has a stamped portion, the containment plate configured and designed to contain a bypass blocker in the stamped portion, the bypass blocker configured to direct cooling fluid over the cooling structure.

[0024] The containment plate may optionally include a bypass blocker that may be applied to the containment plate prior to welding the cover to the containment plate to form the cooling passages, and thus may be designed and constructed as an insert.

[0025] The bypass blocker is configured to guide the cooling liquid. The bypass blocker guides the cooling liquid to flow through the cooling structure of the semiconductor module. By doing so, the bypass blocker prevents the cooling liquid from bypassing the cooling structure of the semiconductor module, or at least reduces the extent to which this bypass occurs. This contributes to an improved cooling power. In addition, the bypass blocker can be designed as a seating surface on which the cover provided on the receiving plate can rest. This ensures vertical alignment of the cover when welding the cover to the receiving plate. Alternatively, the cover may rest alone on the cooling structure of the base plate during the welding procedure. The bypass blocker can be made of plastic or metal. The material of the bypass blocker may be selected depending on the temperature rise of the subsequent process. In yet another alternative embodiment, the bypass blocker is designed to be integrated with the cover.

[0026] The invention further relates to a method for manufacturing a converter including a semiconductor module having a base plate and a cooling housing, the cooling housing including a receiving plate and a cover according to one of the above mentioned features.

[0027] In a first step, the receiving plate is welded to the base plate, for which both the receiving plate and the base plate comprise a weldable material in the connection area, such that when the receiving plate is connected to the base plate, the cooling structure is or can be led to the receiving plate through the openings in the base plate and thus is or can be exposed to the cooling liquid.

[0028] In yet another step, generally following the first step in time, a cover is welded to the receiving plate. This step results in a cooling housing or cooling passage. The welding results in a leak-tight housing through which the cooling fluid can be guided.

[0029] The method further provides the advantage that only the material of the receiving plate, in particular aluminum, is required. In addition, only stamping, cutting and welding methods are required for manufacturing. The material of the receiving plate and cover as well as the material of the inlet and outlet ports is typically aluminum. The openings in the receiving plate are typically cut or punched openings.

[0030] A welding procedure is typically used to connect the receiving plate to the base plate of the half-bridge module and to connect the receiving plate to the cover, which may be automated for increased production.

[0031] In an alternative embodiment, the cooling housing or cooling passage is formed from an extruded material, and the cooling housing or cooling passage is formed from at least two sections.

[0032] In yet another alternative embodiment, the cooling housing or cooling passages are made from die cast aluminum.

[0033] In one development of the method, a bypass blocker is inserted into the receiving plate before the cover is welded to the receiving plate, the bypass blocker being designed as a frame which runs circumferentially around the semiconductor module.

[0034] The invention is illustrated diagrammatically on the basis of an embodiment in the drawings and will be further explained with reference to the drawings, in which identical components are designated with identical reference symbols. [Brief description of the drawings]

[0035] [Figure 1]1 shows an exploded perspective view of the structure of the converter of the invention. [Diagram 2] 1 shows a side view of the converter structure for three embodiments of the base plate, housing plate, and cover arrangement. [Diagram 3] FIG. 2 shows a perspective view of two semiconductor modules welded to a receiving plate. [Figure 4] 1 illustrates a perspective view of three semiconductor modules having bypass blockers welded to and disposed within a receiving plate. [Diagram 5] 1 shows a side view of an inventive converter structure having a base plate, a receiving plate, a bypass blocker and a cover. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] 1 shows an exploded perspective view of the structure of the converter 10 of the invention. Three semiconductor modules 11 are shown, each of which has a substrate 22 and a base plate 12. Cooling ribs 18 are formed on the base plate 12. These three semiconductor modules 11 are assembled into a common receiving plate 14, which has openings 16 corresponding to the number of the semiconductor modules 11. The openings 16 are each configured to receive a semiconductor module 11 such that the cooling ribs 18 are disposed in the openings 16.

[0037] Each of the three semiconductor modules 11 is welded to the receiving plate 14 at a connection area formed around each opening 16. The receiving plate 14 is configured to receive a bypass blocker 21. The bypass blocker 21 may be optionally disposed on the receiving plate 14.

[0038] The bypass blocker 21 is designed as a frame extending circumferentially around the semiconductor module. The receiving plate 14 has a recess in which the bypass blocker 21 can be integrated. The receiving plate 14 together with the bypass blocker 21 can be closed by a cover 15, thus forming a cooling housing or a cooling channel. The cover 15 has inlet and outlet ports 19, 20, through which a cooling liquid can be introduced into the cooling housing or the cooling channel.

[0039] FIG. 2 shows a side view of three embodiments of the structure of the converter 10 shown in FIG. 1 as well as the arrangement of the base plate 12, the storage plate 14 and the cover 15. In FIG. 2a of the first embodiment, the base plate 12 as well as the storage plate 14 and the cover 15 are shown. In this case, the storage plate 14 and the cover 15 each have a flowing curved shape. The storage plate 14 is connected to the base plate 12 via a connection area 23 formed as a weld point. The curved cover 15 is connected to the storage plate 14 via another connection area 23 formed as a weld point.

[0040] In the second embodiment, in Fig. 2b, not only the base plate 12 but also the receiving plate 14 and the cover 15 are shown. In this case, the receiving plate 14 has a curved, flowing form, while the cover 15 is designed to be flat or straight. The receiving plate 14 is connected to the base plate 12 via a connection area 23 formed as a weld point. The straight cover 15 is connected to the receiving plate 14 via another connection area 23 formed as a weld point.

[0041] In the third embodiment, in Fig. 2c, not only the base plate 12 but also the receiving plate 14 and the cover 15 are shown. In this case, the receiving plate 14 is of straight or linear design, while the cover 15 has a curved, flowing form. The straight receiving plate 14 is connected to the base plate 12 via a connection area 23 formed as a weld point. The curved cover 15 is connected to the receiving plate 14 via a further connection area 23 formed as a weld point.

[0042] 3 shows a perspective view of two semiconductor modules 11 welded to a receiving plate 14. Each of the semiconductor modules 11 has a substrate 22 and a base plate 12. A cooling structure in the form of a cooling rib 18 is formed on each of the base plates 12. Each of the two semiconductor modules 11 is arranged in an opening 16 of the receiving plate 14. Each of the two semiconductor modules 11 is connected, in particular welded, to the receiving plate 14 via a connection area 23 formed around the corresponding opening 16. In this case, the cooling rib 18 extends through the opening 16 of the receiving plate 14.

[0043] 4 shows a perspective view of three semiconductor modules 11 welded to a receiving plate 14 and a bypass blocker 21 arranged on the receiving plate 14. Each of the three semiconductor modules 11 is connected, in particular welded, to the receiving plate 14. In this case, cooling ribs 18 extend through openings 16 in the receiving plate 14. The receiving plate 14 has a recess configured to receive the bypass blocker 21. The bypass blocker 21 is designed as a frame surrounding the three semiconductor modules 11.

[0044] 5 shows a side view of the structure of the inventive converter 10 having the base plate 12, the receiving plate 14, the bypass blocker 21, and the cover 15. The cover 15 and the receiving plate 14 each have stamped portions designed as flowing curved shapes. The stamped portions of the receiving plate 14 are formed in an inverse direction to the stamped portions of the cover 15 to form the cooling housing 13 or cooling passages that can receive the cooling structure 18 of the semiconductor module 11.

[0045] The receiving plate 14 is connected to the base plate 12 via connection areas formed as weld points. The curved cover 15 is connected to the receiving plate 14 via connection areas formed as weld points. Furthermore, a bypass blocker 21 is shown in the receiving plate 14. [Explanation of symbols]

[0046] 10 Converter 11 Semiconductor Module 12 Base plate 13 Cooling housing 14 Containment Plate 15 Cover 16 Opening 17 Cooling path 18 Cooling structure, cooling rib 19 Inlet Port 20 Exit Port 21 Bypass Blocker 22 Substrate 23 Connection Area

Claims

1. A converter (10) comprising at least one semiconductor module (11) having a base plate (12) and a cooling housing (13), the cooling housing (13) comprising a receiving plate (14) and a cover (15), the receiving plate (14) having at least one opening (16), the receiving plate (14) being connected to the base plate (12) of the semiconductor module (11) around the at least one opening (16), the cover (15) being connected to the receiving plate (14) along a connection area (23) around the at least one opening (16), either the receiving plate (14) or the cover (15) being designed as a stamped or deep-drawn plate, the base plate (12) having a cooling structure (18), in which a coolant is exposed to the cooling structure, the receiving plate (14) has another opening, the receiving plate (14) configured and designed to receive a bypass blocker (21) at the other opening, the bypass blocker (21) configured to direct the cooling liquid over the cooling structure (18), the bypass blocker (21) thereby preventing the cooling liquid from bypassing the cooling structure of the semiconductor module (11) or reducing the extent to which this bypass occurs; The cover (15) is designed to be partially curved towards the base plate (12), The converter (10) is characterized in that the portion of the cover (15) that is designed to be curved has rounded edges, and the rounded edges are arranged so as not to be in contact with the receiving plate (14) at a right angle.

2. 2. The converter (10) according to claim 1, characterized in that the base plate (12), the receiving plate (14) and the cover (15) are configured to form the cooling housing (13) or a cooling passage (17) for the cooling liquid.

3. 3. The converter (10) according to claim 2, characterized in that either the receiving plate (14) or the cover (15) is designed to be trough-shaped, the depth of the stamped portion of the trough shape providing the height required for the cooling passages (17) and the height required to receive the cooling structure (18).

4. The converter (10) according to any one of claims 1 to 3, characterized in that the cover (15) has an inlet port (19) and an outlet port (20) for fluidly connecting the semiconductor module (11).

5. The converter (10) according to any one of claims 1 to 4, characterized in that the receiving plate (14) is connected to the base plate (12) by welding and / or the cover (15) is connected to the receiving plate (14) by welding.

6. The converter (10) according to any one of claims 1 to 5, characterized in that the receiving plate (14) and the base plate (12) are made from aluminum or an aluminum alloy.

7. A method for manufacturing a converter (10) comprising a semiconductor module (11) having a base plate (12) according to any one of claims 1 to 6 and a cooling housing (13), the cooling housing (13) including a receiving plate (14) and a cover (15), the method comprising the steps of: a) welding the receiving plate (14) to the base plate (12); b) welding said cover (15) to said receiving plate (14).

8. 8. The method of claim 7, further comprising inserting a bypass blocker (21) into the receiving plate (14) before welding the cover to the receiving plate (14).

Images