Stackable power semiconductor component

Abstract

The invention relates to a stackable power semiconductor component, comprising a first power semiconductor and a second power semiconductor, which have a drain contact on a first side and a source contact on an opposite second side, and which are arranged in a half-bridge circuit, the first side of the first power semiconductor and the second side of the second power semiconductor are oriented in the same direction; a lower contact module for thermally connecting the first side of the first power semiconductor and the second side of the second power semiconductor to the lower cooling element and for electrically connecting the drain connection of the first power semiconductor to the first DC voltage input and the source connection of the second power semiconductor to the second DC voltage input; and an upper contact module for thermally connecting the second side of the first power semiconductor and the first side of the second power semiconductor to the upper cooling element and for electrically connecting the source terminal of the first power semiconductor and the drain terminal of the second power semiconductor to the AC voltage output.

Description

Technical Field

[0001] The present invention relates to a component for an inverter, an inverter component for an inverter, and an inverter. Background Art

[0002] The power electronics of electric and hybrid vehicles transfer traction energy from the battery to the electric motor, converting the DC current into AC. This is accomplished by using an AC converter, inverter, or traction converter. Typically, multiple transistors or other power semiconductors are combined into power semiconductor modules and switched at short, regular intervals. MOSFETs (metal oxide semiconductor field-effect transistors), IGBTs (insulated gate bipolar transistors), and JFETs (junction field-effect transistors) are used as switches. In the on state, the battery current is transferred to the motor (conduction phase). These high-frequency switching processes create an AC voltage profile that can then be converted into traction energy in the electric motor. To increase the current-carrying capacity, multiple power semiconductors are often connected in parallel.

[0003] High currents are switched using these power semiconductor modules or power semiconductors, and these generate high temperatures. Active or passive cooling systems are typically used to dissipate the heat, with the heat being dissipated from the power semiconductors via a heat sink to another medium. Therefore, the corresponding components for inverters include, in addition to the power semiconductors themselves, appropriately designed contact modules for electrical and thermal contacting of the power semiconductors, and, in most cases, corresponding cooling structures for dissipating the heat. This creates a heat conduction path from the power semiconductors to the cooling medium. This heat conduction path (thermal path) typically also includes an electrically insulating layer to electrically decouple the cooler or cooling structure.

[0004] In this case, previous approaches generally provide assemblies in which contacts are provided on one or both sides for dissipating heat for the individual power semiconductors.

[0005] In this context, one current approach is to use two-sided cooling of power semiconductors to improve heat dissipation. In this regard, DE 10 2016 121 801 A1 discloses a component, a vehicle, a method of use, and a method for manufacturing the component. The component includes at least one electronic chip. Furthermore, the component includes at least one first heat sink, to which the at least one electronic chip is fastened by means of a first connector. Furthermore, the component includes a second heat sink, which is fastened to or above the at least one electronic chip by means of a second connector. Finally, the component includes an encapsulation material that encapsulates at least a portion of the at least one electronic chip, a portion of the first heat sink, and a portion of the second heat sink. The first connector is designed to have a different melting temperature than the second connector.

[0006] A drawback of previous approaches in this area is that heat dissipation is often suboptimal, which can lead to reduced semiconductor performance. A further challenge lies in efficient manufacturability, where multi-stage manufacturing processes, in particular, often lead to higher costs or more complex production. Furthermore, semiconductor components often have strict requirements regarding the required installation space, which limits their availability. Summary of the Invention

[0007] Based on this, the present invention aims to provide a power semiconductor that can be used and cooled efficiently. In particular, the goal is to create a power semiconductor component that can be flexibly used and achieves efficient and reliable heat dissipation. Furthermore, the goal is to achieve efficient manufacturability of the component to save costs.

[0008] In order to achieve this object, the present invention relates in a first aspect to an assembly for an inverter, comprising:

[0009] a first planar power semiconductor and a second planar power semiconductor, each having a drain connection on a first side and a source connection on an opposite second side, wherein the two power semiconductors are arranged in a half-bridge circuit and the first side of the first power semiconductor and the second side of the second power semiconductor are oriented in the same direction;

[0010] a lower contact module for thermally connecting a first side of the first power semiconductor and a second side of the second power semiconductor to the lower cooling element and for electrically connecting a drain connection of the first power semiconductor to the first DC voltage input and a source connection of the second power semiconductor to the second DC voltage input; and

[0011] An upper contact module is used for thermally connecting the second side of the first power semiconductor and the first side of the second power semiconductor to the upper cooling element and for electrically connecting the source terminal of the first power semiconductor and the drain terminal of the second power semiconductor to the AC voltage output.

[0012] In another aspect, the present invention relates to an inverter assembly for an inverter, the inverter assembly having two or more of the above assemblies, wherein:

[0013] Two or more components are stacked on top of each other in a direction perpendicular to the stacking direction of the planar power semiconductors to form a stack group; and

[0014] A common cooling element is arranged between in each case two stacked modules of a stacking group, so that the lower contacting modules of a first module of the stack and the upper contacting modules of a second module of the stack are thermally connected to the common cooling element.

[0015] In another aspect, the present invention relates to an inverter for an electric vehicle, the inverter having the assembly described above or the inverter assembly described above.

[0016] Preferred embodiments of the invention are described in the dependent claims. It should be understood that the features mentioned above and those explained below can be used not only in the combinations indicated in each case, but also in other combinations or individually, without departing from the scope of the invention. In particular, the assembly, inverter assembly, and inverter can be implemented in accordance with the embodiments described for the assembly and inverter assembly in the dependent claims.

[0017] According to the present invention, two power semiconductors (chips) are arranged in a half-bridge circuit. The power semiconductors used are designed to be planar, meaning they are distributed in a specific plane and have a greater extent within this plane than in height. The two power semiconductors are designed identically and each have a first current connection (drain connection) on one side (outer surface) and a second current connection (source connection) on the other side (opposite outer surface). In the assembly according to the present invention, one of the power semiconductors is oriented oppositely or in opposite directions to the other power semiconductor. The top side of the first power semiconductor and the bottom side of the second power semiconductor are oriented in the same direction. In other words, one of the power semiconductors is oriented oppositely or upside down relative to the other power semiconductor. The drain connection of one power semiconductor and the source connection of the other power semiconductor are oriented in the same direction.

[0018] In the assembly, two power semiconductors are contacted from both sides, or from above and below, using two contact modules. The contact modules provide thermal connection for heat dissipation and electrical contact for inputting and outputting DC voltage. A half-bridge circuit comprises two DC voltage inputs (DC positive and DC negative) and an AC voltage output (AC). The inputs and outputs are connected to the drain and source terminals of the two power semiconductors. In this case, one power semiconductor is a topological high-side switch, while the other is a topological low-side switch. Thermal contact is also established on the top and bottom sides of the two power semiconductors via two contact modules, each connected to an associated cooling element.

[0019] Compared to previous approaches, the assembly according to the present invention comprises two power semiconductors, which are thermally and electrically connected via a shared upper and lower contact module. The structure of the assembly according to the present invention enables a compact power core design. In particular, it allows for the stacking of multiple assemblies (in a direction perpendicular to the direction in which the planar power semiconductors extend). This enables a compact design and simple scalability. Given varying space requirements, this dimension can generally be increased in this direction, thereby achieving compatibility. The double-sided cooling of the power semiconductors provided according to the present invention achieves low thermal resistance and, consequently, high power density. In this regard, the stacking of different assemblies in the inverter assembly provided according to the present invention enables compatibility with varying requirements and the adaptation of varying power requirements. This results in efficient manufacturability with high flexibility and variability.

[0020] In a preferred design, the lower and / or upper contact modules are constructed as direct copper bonding (DBC) structures. The DBC structure enables tight electrical and thermal connections between the power semiconductor and the contact module, enabling efficient heat dissipation. Electrical insulation can be provided by an insulating layer (preferably ceramic). Conductor trace structures and contact surfaces can be provided on the DBC substrate, ensuring both good cooling and good electrical contact. This allows for efficient manufacturability while maintaining high performance.

[0021] In a preferred design, the contact module comprises a first copper layer on the side facing the power semiconductor, a second copper layer on the side facing the cooling element, and a ceramic layer disposed between the copper layers. The DBC substrate structure, consisting of copper, ceramic, and additional copper layers, achieves efficient electrical contact while ensuring good thermal connection. Furthermore, the ceramic layer ensures electrical insulation, thus achieving efficient manufacturability while maintaining high performance.

[0022] In a preferred embodiment, the assembly includes a casting for mechanical stability, wherein the thermal and electrical contacts of the contact module extend from the casting. In particular, the casting can be performed using a suitable casting compound. In particular, electrical insulation can be ensured. For example, a polymer casting can be used. The casting achieves high stability and resistance to mechanical influences.

[0023] In a preferred embodiment, two power semiconductors are arranged side by side. Arranged side by side here means arranged essentially in the same plane. A small offset perpendicular to this plane can be provided to reflect the differently shaped source and drain sides of the power semiconductors. The side-by-side arrangement at a small distance allows for a smaller overall size. This results in efficient manufacturability with good scalability.

[0024] In a preferred embodiment of the inverter assembly according to the present invention, the inverter assembly includes two additional, correspondingly configured stacking groups. These three stacking groups are assigned to the three phases of the electric motor and are arranged side by side. Here, side-by-side arrangement refers to an arrangement parallel to a vertical axis that runs orthogonally to the planar power semiconductors. Therefore, side-by-side arrangement corresponds to an offset in the direction of the surface of the planar power semiconductors. Using three stacking groups for the three phases of the electric motor allows for efficient use of installation space.

[0025] In a preferred design of the inverter assembly, the three contact modules of the three stacked groups are thermally connected to a common cooling element. Particularly advantageously, the lower contact modules are each connected to a common lower cooling element, while the upper contact modules are connected to a common upper cooling element. This results in two common cooling elements, each forming a lower cooling element or an upper cooling element. This allows for efficient use of installation space and also enables cost-effective production.

[0026] In a preferred design of the inverter assembly, the electrical contact points of the contact modules of two, three, or more components in a stacked stack are led out of the stacked stack laterally, parallel to the planar power semiconductors. Preferably, the electrical contact points for the first and second DC voltage inputs are arranged on a first side of the stacked stack, while the electrical contact points for the AC voltage outputs are arranged on a second side of the stacked stack. This further enables efficient use of installation space. Furthermore, the efficient routing of the corresponding contact points enables efficient contacting of the half-bridge circuit, thus enabling efficient installation.

[0027] In a preferred embodiment of the inverter assembly, the half-bridge capacitors are arranged above or below the stack in the stacking direction. The stacking direction is a vertical direction parallel to the vertical axes of the individual power semiconductors. By arranging the half-bridge capacitors above or (preferably) below the stack in the stacking direction, space utilization is improved. Alternatively, the half-bridge capacitors can be positioned in different directions to achieve synchronization of the half-bridges, if necessary, and to compensate for any current errors.

[0028] Sintered connections can be provided between the layers of a contact module or a plurality of contact modules, as well as between a contact module and a power semiconductor. Sintering creates a material-bonded connection, through which heat can also be transferred.

[0029] Here, an inverter assembly refers specifically to an assembly for use in an inverter or inverter structure. Typically, multiple power semiconductors are combined into a power semiconductor module. A power semiconductor module typically includes multiple power semiconductors and can also be referred to as an assembly. A power semiconductor specifically corresponds to an electronic chip having one or more integrated circuit components. A power semiconductor is specifically a transistor. For example, MOSFETs, IGBTs, and JFETs can all be used as power semiconductors. Multiple identical or different power semiconductors can be combined in an assembly or power semiconductor module. Power semiconductors are specifically semiconductor switches. The terms "lower" or "upper" with respect to various modules or components are used solely for clarity and differentiation. It goes without saying that an assembly can also be arranged in reverse or upside down. This also applies to the distinction between "first" and "second." The first and second sides of a planar power semiconductor are understood to specifically refer to the mutually opposing outer surfaces of the power semiconductor having the greatest planar extent. The assembly according to the present invention is particularly suitable for use in vehicles or inverter assemblies of vehicles. A planar configuration, as used herein, specifically refers to a planar configuration in which the extent in two axes is significantly greater than the extent in a third axis (the height axis). BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be described and explained in more detail below with reference to some selected embodiments in conjunction with the accompanying drawings. In the drawings:

[0031] Figure 1 A schematic diagram showing a vehicle having an assembly and an inverter according to the present invention;

[0032] Figure 2 A schematic diagram showing the heat path from the semiconductor to the cooling medium in a prior art assembly;

[0033] Figure 3 A schematic diagram of an assembly according to the invention is shown in a sectional view parallel to the plane of the power semiconductor;

[0034] Figure 4 A schematic diagram of the assembly according to the invention is shown in a sectional view in a section plane orthogonal to the plane of the power semiconductor;

[0035] Figure 5 Shown perpendicular to Figure 3 and Figure 4 corresponding sectional views of the plane in ; and

[0036] Figure 6 A schematic diagram shows an embodiment of an inverter assembly according to the invention having three stacked groups for the three phases of an electric motor. DETAILED DESCRIPTION

[0037] Figure 1 A vehicle 10 is schematically shown with an inverter 12 according to the present invention. Inverter 12 is arranged between a battery 14 and an electric motor 16 of vehicle 10 to convert the direct current of battery 14 into the alternating current required by electric motor 16. Inverter 12 includes an inverter assembly 18, which contains three stacked groups 20, each with two components 22. Each component 22 includes a power semiconductor or semiconductor switch, which can be designed, in particular, as a MOSFET. It goes without saying that the illustration is schematic, and components are not shown to improve clarity.

[0038] A characteristic of current inverters is that the switching semiconductors (power semiconductors) must be actively cooled to dissipate switching losses and power losses. To dissipate these losses, a heat conduction path is created from the semiconductors to the cooling medium. In prior art components, this heat path includes, for example, Figure 2 Parts shown.

[0039] To dissipate heat, power semiconductors 24 are arranged on an upper copper layer 26, which in turn is arranged on a ceramic layer 28 and a lower copper layer 30. The structure consisting of upper copper layer 26, lower copper layer 30, and ceramic layer 28 is also referred to as a direct bonded copper (DBC) structure. The DBC structure is arranged on a cooling plate 32 (cooling element), which is in contact with a cooling medium 34. The heat path from power semiconductors 24 to cooling medium 34 is formed across various components, with the DBC structure forming an electrically insulating layer.

[0040] Thermal resistance, i.e. Figure 2 The sum of the different thermal resistances of the various components in the semiconductor has a great influence on the performance of the semiconductor. Figure 2 The serpentine structure of the cooling plate 32 shown, and the pin-fin structure are also commonly used.

[0041] To optimize the heat path, thermal resistance must be minimized. This includes electrical resistances, such as the insulating ceramic layer 28, as well as resistances required for manufacturing. This resistance is particularly necessary for manufacturing, as is the resistance of the copper layers 26 and 30, which are required for structural and connection purposes, and whose thickness can be optimized for heat conduction. Furthermore, the resistance required for manufacturing also includes the resistance of the cooling plate 32, which cannot be optimized for heat conduction due to manufacturing and assembly limitations. Finally, the resistance required for manufacturing also includes the transition between the cooling plate 32 and the coolant 34, which, again due to manufacturing and assembly limitations, is greater than technically required.

[0042] Manufacturing and assembly constraints in the cooling plate 32 and the transition to the coolant 34 are determined by the manufacturing process, the cooling plate 32 and its cooling structure, and the assembly process (typically, sintering the encapsulated DBC onto the cooling plate). Manufacturing often involves a pressing process, which requires maintaining a minimum thickness for the cooling plate. Furthermore, the cooling structure or the design of the cooling plate is subject to limitations such as minimum spacing, diameter, and, for example, the shape of the pins. During sintering, process-related factors require a contact pressure of 10 MPa to 20 MPa at the joint, which affects the thickness of the cooling plate. Furthermore, since the cooling structure itself is generally unable to absorb the contact pressure, the pressing tool must be shaped to provide support for this. This support is typically provided by a negative mold for the cooling structure.

[0043] exist Figure 3 、 Figure 4 and Figure 5 An exemplary embodiment of an assembly 22 according to the invention is schematically illustrated in FIG. In particular, three different sectional views of the assembly 22 are shown here. The assembly 22 according to the invention comprises a first planar power semiconductor 36, a second planar power semiconductor 38, a lower contact module 40 and an upper contact module 42. Figure 3 、 Figure 4 and Figure 5 In the diagram of FIG, the y-axis extends parallel to the vertical direction of the planar power semiconductors 36 and 38 or orthogonally to the plane of the power semiconductors. The x-axis and the z-axis lie in the plane of the planar power semiconductors 36 and 38.

[0044] According to the present invention, it is particularly advantageous to use a DBC substrate having two electrically isolated power semiconductors 36 and 38 that are identical but mounted in an inverted orientation relative to one another. The power semiconductors 36 and 38 are oriented such that the first power semiconductor 36 faces downward with its drain connection on the first side, representing a topological low-side switch. The second power semiconductor 38 faces downward with its second side, or source surface, representing a topological high-side switch. Contact is then made on both sides (the first and second sides, or the drain and source connection sides) with a lower contact module 40 and an upper contact module 42. In particular, a lower cooling element 49 and an upper cooling element 50 are provided for cooling. In particular, in this arrangement, each contact module 40 and 42 has a first copper layer 44 on the side facing the respective power semiconductor 36 and 38, and a second copper layer 46 on the side facing the respective cooling element 49 and 50. A ceramic layer 48 is arranged between the copper layers 44 and 46 for electrical insulation. Furthermore, a potting 52 is preferably provided for mechanical stabilization. Corresponding electrical contact points protrude from the encapsulation 52 for contacting.

[0045] Especially if you can Figure 3 As can be seen in FIG, two power semiconductors 36, 38 are arranged side by side. The two power semiconductors are arranged substantially in the same plane.

[0046] Especially from Figure 4 The electrical contacts can be seen in the figure. The DC voltage input (DC) is arranged on one side, and the AC voltage output (AC) is arranged on the other side. The second power semiconductor is arranged behind the first power semiconductor 36. In particular, the connection to the DC side can be arranged at the end in the Z direction.

[0047] Especially if you can Figure 5 As can be seen in FIG, the two power semiconductors 36 and 38 are arranged in parallel.

[0048] exist Figure 6 FIGURE 1 schematically illustrates a preferred embodiment of an inverter assembly 18 according to the present invention. The inverter assembly 18 comprises three stacked groups 20, which are assigned to the three phases u, v, and w of the electric motor and are arranged side by side. In the illustrated embodiment, each stacked group 20 includes three stacked assemblies 22. A common cooling element 49, 50 is arranged between each two stacked assemblies 22. In other words, the lower cooling element 49 of the upper assembly 22 serves as the upper cooling element 50 of the lower assembly 22.

[0049] exist Figure 6In the embodiment shown, the three contact modules of three stacking groups 20 (parallel contact modules in the three stacking groups) are also shown to be thermally connected to a common cooling element 49, 50. Thus, the cooling element can extend through all three stacking groups, thereby having the effect of cooling a plurality of different components 22.

[0050] also, Figure 6 An electrical contact is shown in which two DC voltage inputs DC+ and DC− are arranged on a common side of the respective stacking group 20 .

[0051] also, Figure 6 It is shown that a half-bridge capacitor CAP is provided, which is arranged below the stacking group in the stacking direction of the different stacking groups 20 .

[0052] The present invention has been fully described and explained with reference to the accompanying drawings and the specification. The description and explanation are to be understood as illustrative rather than restrictive. The present invention is not limited to the disclosed embodiments. Other embodiments and variations may be developed by those skilled in the art through application of the present invention and careful consideration of the drawings, the disclosure, and the claims.

[0053] In the claims, the terms "comprising" and "having" do not exclude the presence of other elements or steps. The indefinite article "a" or "an" does not exclude the presence of a plurality. A single element or a single unit may implement the functions of the units recited in several claims. Elements, units, interfaces, devices and systems may be implemented partly or completely by hardware and / or software. The mere mention of certain measures in several different dependent patent claims does not mean that a combination of these measures cannot be used to advantage. The reference signs in the patent claims are not to be understood as restrictive.

[0054] Reference Signs List

[0055] 10 vehicles

[0056] 12 Inverter

[0057] 14 batteries

[0058] 16 motors

[0059] 18 Inverter components

[0060] 20 stacking groups

[0061] 22 components

[0062] 24 Power Semiconductors

[0063] 26 copper layer

[0064] 28 ceramic layers

[0065] 30 lower copper layer

[0066] 32 cooling plates

[0067] 34 Cooling medium

[0068] 36 First Power Semiconductor

[0069] 38 Second Power Semiconductor

[0070] 40 lower contact module

[0071] 42 upper contact module

[0072] 44 first copper layer

[0073] 46 Second copper layer

[0074] 48 ceramic layers

[0075] 49 lower cooling element

[0076] 50 cooling elements

[0077] 52 casting department

Claims

1. A component (22) for an inverter (12), comprising: A first planar power semiconductor (36) and a second planar power semiconductor (38) each having a drain connection on a first side and a source connection on an opposite second side, wherein: Two power semiconductors are arranged in a half-bridge circuit, and a first side of the first power semiconductor and a second side of the second power semiconductor are oriented in the same direction; a lower contact module (40) for thermally connecting a first side of the first power semiconductor and a second side of the second power semiconductor to a lower cooling element (49), and for electrically connecting a drain terminal of the first power semiconductor to a first DC voltage input and a source terminal of the second power semiconductor to a second DC voltage input; and An upper contact module (42) is used to thermally connect the second side of the first power semiconductor and the first side of the second power semiconductor to an upper cooling element (50), and to electrically connect the source terminal of the first power semiconductor and the drain terminal of the second power semiconductor to an AC voltage output terminal.

2. The assembly (22) according to claim 1, wherein The lower contact module (40) and / or the upper contact assembly (42) are constructed as a direct copper bonding structure, namely, a DBC structure.

3. Assembly (22) according to any one of the preceding claims, wherein The contact modules (40, 42) each comprise a first copper layer (44) on the side facing the power semiconductor (36, 38) and a second copper layer (46) on the side facing the cooling element (49, 50), as well as a ceramic layer (48) arranged between the copper layers.

4. The component (22) according to any one of the preceding claims, comprising a casting (52) for mechanical stabilization, wherein: Thermal and electrical contact points of the contact modules (40, 42) protrude from the encapsulation.

5. Assembly (22) according to any one of the preceding claims, wherein Two power semiconductors (36, 38) are arranged side by side.

6. Inverter assembly (18) for an inverter (12), comprising two or more assemblies (22) according to any one of the preceding claims, wherein: Two or more components are arranged stacked on top of each other in a direction perpendicular to the stacking direction of the planar power semiconductor and form a stack group (20); as well as A common cooling element (49, 50) is arranged between each two stacked components of a stacking group, so that the lower contact module (40) of the first of the stacked components and the upper contact module (42) of the second of the stacked components are thermally connected to the common cooling element.

7. The inverter assembly (18) according to claim 6, comprising two further correspondingly configured stacking groups (20), wherein: Three stacking groups are assigned to three phases of the electric motor and are arranged next to each other.

8. The inverter assembly (18) according to any one of claims 6 to 7, wherein the three contact modules (40, 42) of the three stacked groups (20) are thermally connected to a common cooling element (49, 50).

9. The inverter assembly (18) according to any one of claims 6 to 8, wherein: Electrical contact points of contact modules (40, 42) of two or more components of a stacking group (20) are led out of the stacking group in a lateral direction parallel to the planar power semiconductors (36, 38); as well as Preferably, electrical contact points for the first DC voltage input and the second DC voltage input are arranged on a first side of the stacking group, while electrical contact points for the AC voltage output are arranged on a second side of the stacking group.

10. The inverter assembly (18) according to any one of claims 6 to 8, wherein: The half-bridge capacitor is arranged above or below the stacking group (20) in the stacking direction.

11. An inverter (12) for an electric vehicle, comprising the component (22) according to any one of claims 1 to 5 or the inverter component (18) according to any one of claims 6 to 10.

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