Power module with integrated aluminum snubber capacitor

Abstract

The invention relates to a power module comprising a power device, a substrate, a circuit carrier and a flat stacked aluminum electrolytic buffer capacitor comprising a layered structure of a cathode layer, a separator layer comprising paper and electrolyte, and an anode layer comprising an aluminum material with an aluminum oxide dielectric, wherein the circuit carrier is mounted on the substrate, the power device and the buffer capacitor are placed on the circuit carrier within the power module and electrically connected to the circuit carrier, the circuit carrier is configured for providing an electrical connection between the power device and the buffer capacitor.

Description

Technical Field

[0001] This invention relates to a power module with an integrated aluminum electrolytic buffer capacitor. Background Technology

[0002] Power modules are used in many different applications. Their general purpose is to control and convert electrical energy. An example of a power module is the IGBT (Insulated Gate Bipolar Transistor) module, which can be used to invert power from DC to AC. Voltage spikes or transients are generated during power conversion. These spikes need to be suppressed in order to use the output voltage, as they can damage devices and applications powered by the power module, or they require a high robustness margin.

[0003] Snubber capacitors are commonly used in circuits to suppress voltage spikes. The selection of a snubber capacitor depends on the operating conditions of the power module, but typically the capacitor needs to withstand high peak currents, high voltage stress, and high temperatures. Currently, ceramic and film capacitors are used as snubber capacitors because they can withstand these high temperatures and stresses. However, the heatsink thermal resistance of these capacitors is not ideal, making them difficult to cool sufficiently during operation, and therefore they cannot be integrated into the power module itself. In high-voltage power modules, snubber capacitors need to have high capacitance, again primarily referring to ceramic and film capacitors.

[0004] However, ceramic capacitors are expensive. Integrating capacitors into power modules requires a deep understanding of the capacitors themselves to ensure robust design due to their thermo-mechanical properties. Ceramic capacitors also lack self-healing capabilities. Short circuits are the end of the lifetime failure mode, which is unacceptable in most applications. To meet robustness requirements, ceramic capacitors are often connected in series to allow for the possibility of redundancy for a single capacitor. Furthermore, due to their low parasitic series resistance, ceramic capacitors can sometimes cause ringing and voltage spikes, which can be heavily dependent on temperature, frequency, and voltage. These properties are undesirable.

[0005] Polymer film capacitors lack high energy density, making them very large and difficult to integrate. Polymer materials have very poor thermal conductivity. Therefore, parasitic resistance cannot be used to generate significant power losses. For buffer applications, ohmic resistors must be additional components. The metallization of film capacitors must be very thin, and the film temperature must be low enough to provide the capacitor with self-cleaning capabilities.

[0006] Therefore, an improved and simpler power module would be advantageous, and in particular, a buffer capacitor that can be integrated into the power module would be advantageous.

[0007] Purpose of the invention

[0008] Another object of the present invention is to provide an alternative to the prior art.

[0009] Specifically, the purpose of this invention can be seen as providing a power module that solves the problems of the prior art mentioned above by utilizing a power module buffer capacitor. Summary of the Invention

[0010] Therefore, in a first aspect of the invention, the above-mentioned and several other objectives are intended to be achieved by providing a power module that may include power devices, a substrate, a circuit carrier, and a flat stacked aluminum electrolytic buffer capacitor, which may include,

[0011] - A hierarchical structure, which may include:

[0012] - Cathode layer

[0013] - A separator layer, which may contain paper and electrolyte, and

[0014] - Anode layer, which may contain aluminum material with alumina dielectric.

[0015] The circuit carrier can be mounted on a substrate, and the power devices and buffer capacitors can be placed on the circuit carrier or substrate within the power module. Preferably, they are electrically connected to the circuit carrier by one or more conductive lines and one or more pads. The circuit carrier can be configured to provide electrical connection between the power devices and the buffer capacitors.

[0016] In embodiments of the present invention, the stacked aluminum electrolytic buffer capacitor can be connected to the circuit carrier by an anode layer or a cathode layer disposed on the circuit carrier, and the corresponding cathode layer or anode layer is electrically connected to the circuit carrier through a connector.

[0017] In embodiments of the present invention, the bonding layer may be placed between the stacked aluminum electrolytic buffer capacitor and the substrate or circuit carrier.

[0018] In an embodiment, the stacked aluminum electrolytic buffer capacitor may have a top layer, an intermediate layer, and a bottom layer, wherein the top layer is an anode layer or a cathode layer, the intermediate layer may be a separator layer, and the bottom layer may be a corresponding remaining cathode layer or anode layer, wherein the top layer may extend in a direction in the plane defined by the layer to extend beyond the intermediate layer and the bottom layer, thereby electrically connecting to the circuit carrier.

[0019] In other embodiments of the invention, the anode or cathode layer may encapsulate the other layers of the stacked aluminum electrolytic buffer capacitor into a can shape so that both the anode and cathode layers can be electrically connected to the circuit carrier for wireless bonding.

[0020] In embodiments, the bottom layer can extend in a direction defined by the plane of the layer, which is different from the top layer, so as to extend beyond the junction layer, so that it can be electrically connected to the circuit carrier.

[0021] In other embodiments of the invention, the substrate can also comprise a heat sink, or can be connected to an external heat sink.

[0022] In embodiments, the electrolyte can be a polymer solution, such as a PEDOT:PSS polymer mixture.

[0023] In embodiments, if the capacitor is placed directly on the substrate, the anode foil, the cathode foil or the junction layer can be electrically insulated towards the substrate.

[0024] In embodiments, the capacitor can be electrically insulated on all its non-insulated surfaces, preferably by covering the surfaces with a non-conductive material.

[0025] In embodiments, the channels can be etched in the aluminum material, so that the electrolyte penetrates the channels.

[0026] In embodiments, two or more capacitors can be placed in series or in parallel, by stacking the capacitors and / or by arranging them on a circuit carrier.

[0027] In embodiments, if the capacitors are stacked and if the capacitors are placed electrically insulated in series, a thermally conductive layer can be placed between the stacked capacitors.

[0028] In embodiments of the invention, the capacitor can be mechanically pressed onto the substrate or circuit carrier, by using fasteners such as rivets, clamps or springs.

[0029] In embodiments, in which the capacitor can be configured to be soldered, connected by an adhesive or sintered to the circuit carrier.

[0030] The invention is particularly, but not exclusively, advantageous for obtaining a simple and cost-effective design, a sufficiently high reliability, a small and well-coolable buffer capacitor.

[0031] A power module preferably refers to an assembly comprising several power components and capacitors, which are connected to each other to perform a power conversion function.

[0032] A power device preferably refers to a switch or a rectifier in power electronics.

[0033] A circuit carrier preferably refers to a surface in which the components of a power module are placed, and which has the ability to provide the correct circuitry for implementing a circuit design.

[0034] The substrate preferably refers to the surface on which the circuit carrier is positioned. The substrate can be a heat sink or an element connected to a heat sink.

[0035] The buffer capacitor preferably refers to a polymer aluminum electrolytic capacitor used to absorb voltage transients or similar effects from the power module.

[0036] The individual aspects of the present application can each be combined with any of the other aspects. These and other aspects of the present application will become apparent from the description provided herein. BRIEF DESCRIPTION OF DRAWINGS

[0037] A power module according to the present application will now be described in more detail with respect to the accompanying drawings. The drawings show one way of implementing the present application and should in no way be interpreted as limiting to other possible embodiments falling within the scope of the appended claims.

[0038] Figure 1 An embodiment of a power module is schematically shown,

[0039] Figure 2 An embodiment of the layout of a circuit carrier is shown,

[0040] Figure 3 An embodiment of a power module is shown, wherein a bonding layer is included,

[0041] Figure 4 An embodiment of the connection of a capacitor to a circuit carrier is shown,

[0042] Figure 5 An embodiment of a power module is shown,

[0043] Figure 6 An embodiment of a connection of a capacitor to a circuit carrier is shown, Figure 4 including a bonding layer for a capacitor in a power module,

[0044] Figure 7 Another embodiment of a capacitor is shown,

[0045] Figure 8 An embodiment is shown including a fastener,

[0046] Figure 9 An embodiment of a stacked capacitor connected to a heat sink is shown,

[0047] Figure 10 Highly etched channels in an anode foil are illustrated,

[0048] Figure 11 An embodiment of the present application is shown, wherein the capacitor is insulated and connected to a circuit carrier,

[0049] Figure 12A stacked capacitor is shown, which is placed in series and connected to the circuit carrier. Detailed Implementation

[0050] Reference Figure 1 The following illustrates an exemplary embodiment of the invention. In this embodiment, a power module 1 is shown, comprising a power device 1a for current and voltage switching, a substrate 3, a circuit carrier 2 for facilitating electrical connections between components of the power module, and stacked aluminum electrolytic buffer capacitors 5. In some embodiments, the substrate 3 will possess only thermally and mechanical properties. In this embodiment, the circuit carrier will be selected such that it is electrically insulated from the substrate. In other embodiments, the substrate is electrically insulated by its inherent properties or by an additional layer between the substrate and the circuit carrier.

[0051] In the illustrated embodiment, the flat stacked aluminum electrolytic buffer capacitor 5 is used to absorb voltage spikes, such as voltage transients, in the power module 1 generated by the power device 1a. The stacked aluminum electrolytic buffer capacitor 5 includes:

[0052] - Hierarchical structure, including:

[0053] - Cathode layer, comprising cathode foil 18

[0054] - Separator layer, comprising paper 11 and electrolyte 12, and

[0055] - Anode layer, comprising aluminum material 9 and alumina dielectric 10.

[0056] By scaling the surface area of ​​a capacitor, the capacitance / resistance ratio can be altered depending on the application, with a larger area yielding higher capacitance and lower resistance. The type and thickness of the electrolyte in the separator layers can also be used as modifying parameters that alter capacitor characteristics, such as the equivalent series resistance (ESR), which ideally should be as low as possible. The thickness and type of the dielectric will define the capacitance per unit area. Therefore, by changing the size and composition of the capacitor's layers, it can be adapted to the specific requirements of power devices, such as ensuring operation in high-temperature ranges typically exceeding 100 degrees Celsius and high-voltage ranges typically exceeding 200V.

[0057] In the examples, the electrolyte is a polymer solution, such as a PEDOT:PSS polymer mixture.

[0058] Stacked aluminum electrolytic snubber capacitors utilize a winding-free layered sequence construction, enabling them to be configured as follows: Figure 1The flat stack is shown. The advantages of using stacked aluminum electrolytic snubber capacitors are low parasitic inductance and high capacitance per unit area, which leads to reduced switching losses in the power module. Furthermore, their flat stacking allows for direct mounting within the power module, enabling better heat transfer to the module's substrate. The capacitors also feature a robust aluminum substrate, making the overall structure more robust and flexible compared to ceramic and film capacitors.

[0059] In this embodiment, the dielectric 10 is of the Al2O3 type. Furthermore, in this embodiment, the channel 21 is etched into the aluminum material 9 to enlarge the surface area and obtain the highest possible capacitance per unit area, and the channel is covered by the dielectric 10 so that the electrolyte permeates the channel; see the side view as a representation of this structure. Figure 10 This provides a larger contact surface area for the capacitor layer, which increases the capacitance per unit area.

[0060] Return to reference Figure 1 In the power module 1, the circuit carrier 2 is mounted on the substrate, so that the components of the power module can be placed on the circuit carrier 2 and further electrically connected to the circuit carrier, which will provide an implementation of the circuit system of the power module 1 via the circuit carrier 2.

[0061] like Figure 2 As shown, the circuit carrier 2 consists of one or more wires and one or more pads, allowing the components to be electrically connected to each other in a desired configuration using conductive materials. In the case of a parallel buffer capacitor, two wires are required: one negative wire and one positive wire.

[0062] In most embodiments, the circuit carrier consists of a metal strip that carries current and voltage, disposed on an electrically insulating substrate placed on a substrate, such that no charge is carried to the substrate. The configuration of the circuit carrier will depend on the desired circuit design, and... Figure 2 Not all wires are shown.

[0063] In this embodiment, the components of the power module are power device 1a and buffer capacitor 5. The circuit carrier will provide a circuit design that electrically connects these components, such as... Figure 2 As shown, this allows the buffer capacitor 5 to absorb voltage spikes from the power devices. This can be a parallel connection for IGBT modules or a series connection for other types of circuit topologies. If multiple capacitors are placed in series, the circuit carrier will provide this electrical connection between them. The electrical connection will depend on the power module circuit design and application.

[0064] Because the capacitors are constructed as a flat stack, the entire length of the capacitor base is in direct contact with the circuit carrier or substrate. Therefore, it is preferable that at least one side of the stack is flat to facilitate good contact with the circuit carrier or substrate. This ensures that the heat generated by the buffer capacitors is effectively dissipated to the substrate or circuit carrier.

[0065] In some embodiments of the invention, the stacked aluminum electrolytic buffer capacitor 5 is connected to the circuit carrier by a flat anode or cathode layer disposed on the circuit carrier, thereby providing a connection by physical contact, and the corresponding cathode or anode layer is electrically connected to the circuit carrier by a connector 24.

[0066] exist Figure 1 In the diagram, the cathode layer 6 is shown as the top layer, connected to the corresponding circuit carrier 2 by connector 24. This connector 24 can be a wire, joined to the circuit carrier 2 using ultrasonically welded wire bonding (equivalent to bonding wires on semiconductor components), but other connection types are also conceivable, such as top terminal connections, pin connections, etc. The anode layer is connected to the positive terminal portion of the circuit carrier, while the cathode layer is connected to the negative terminal portion. Lower layers can also be connected to the circuit carrier similarly to the top layer, or placed on the circuit carrier for easy electrical connection.

[0067] In an embodiment, such as Figure 3 As shown, a bonding layer 23 is placed between the stacked aluminum electrolytic buffer capacitor 5 and the circuit carrier. This bonding layer 23 ensures good thermal and electrical contact between the layer connected to the circuit carrier and the circuit carrier. Therefore, the bonding layer is preferably selected from Al, Ag, Cu, Sn, Pt, Pd, Ni, Au, etc. This bonding preferably occurs as a material-to-material bonding. This means that at least one side of the capacitor should have a suitable plating for bonding the capacitor to the circuit carrier. Without such a bonding layer, the capacitor may have areas that do not directly contact the circuit carrier. Therefore, bonding is advantageous in this embodiment because the anode foil and cathode foil may contain impurities and dielectrics that do not form ideal electrical contact with the circuit carrier.

[0068] The bonding layer 23 can also be an electrically insulating but thermally conductive adhesive. This can be advantageous if the capacitor is placed on the substrate, or when the capacitor is placed inside a metal casing (which is placed on the substrate or circuit carrier), or when the electrical connection is made outside the coverage area of ​​the buffer capacitor.

[0069] In this embodiment, the way to avoid wire connection is by using Figure 4The connection concept is illustrated. In this embodiment, the stacked aluminum electrolytic buffer capacitor 5 has a top layer (anode or cathode layer), an intermediate layer (containing electrolyte and paper layers), and a bottom layer (containing the corresponding remaining cathode or anode layer). Contact points are created by extending the top layer in a direction defined by the plane of the layer, such that the layer extends beyond the intermediate and bottom layers. Figure 5 , 25), for electrical connections from the top layer to the corresponding circuit carrier pads via a bonding technique that typically cannot be performed on top of the capacitor like soldering, as these types of techniques would impose excessive stress and / or temperature on the capacitor stack. The general idea of ​​these embodiments is that the bonding area should be outside the protruding portion of layer 7. Figure 4 As shown, this can also be done for lower layers.

[0070] Figure 5 It shows the use of Figure 4 The concept and considered connection scheme of the embodiment are as follows, where the cathode side is the top layer. Since both the cathode and anode layers comprise aluminum foil, they are flexible to a certain extent, making it possible to extend them horizontally, and thus vertical extensions are possible, allowing them to be connected to a circuit carrier. Figure 5 In this configuration, there is no bonding layer, but the anode and cathode extensions are advantageously connected using welding, sintering, or other conventional electrical connection types, which can be accomplished through a bonding layer. This connection can also be achieved through a press-fit connection, whereby electrical contact is achieved by mechanically pressing the anode or cathode foil downwards onto the circuit carrier or a combination thereof.

[0071] Figure 4 and 5 The connection is preferred because it is difficult to solder the bottom of the capacitor to the circuit carrier. By extending the anode layer 8 and the cathode layer 9, the electrical connection occurs "outside" the initial coverage area of ​​the capacitor, which improves the connection. See [link to relevant documentation]. Figure 6 In this implementation, both the anode and cathode layers extend and connect to the circuit carrier in this manner. The separator layer 7 extends in the same way to ensure it covers the end of the lower anode or cathode layer. The separator layer is conventional and also extends slightly larger than the anode and cathode layers to completely isolate them.

[0072] like Figure 6 As shown, a bonding layer 23 may also be present, such that in this embodiment, the bonding layer is preferably a thermally conductive adhesive to take advantage of the thermal transfer properties and electrical insulation of the aluminum buffer capacitor to ensure that there is only one contact point 25 for the anode and cathode layers to the circuit carrier.

[0073] This approach facilitates connecting the lower layers of the capacitor to the substrate. This is useful when the capacitor is placed on a non-conductive layer (such as a substrate). Figure 4 As shown, the anode and cathode foils of this layer are typically extended and connected to the circuit carrier. Figure 6 The preferred connection type is one where, even with the addition of a conductive bonding layer, it is difficult or impossible to ensure a perfect connection between the bottom layer and the circuit carrier. Therefore, it is preferable that the bonding layer is used only to establish a good thermal contact between the capacitor and the circuit carrier, and that the electrical connection is made outside the capacitor's coverage area.

[0074] A third way to bond capacitors to the substrate and circuit carrier is... Figure 7 As seen in the image, the anode or cathode layer encapsulates the other layers of the stacked aluminum electrolytic buffer capacitor 5 in a can-like shape, allowing for wireless connection of the anode and cathode layers to the circuit carrier. For example... Figure 7 As shown, in order to obtain good thermal and electrical properties, a bonding layer can be advantageously used in this embodiment.

[0075] In construction Figure 7 When configuring the power supply module, it is important to remember that the electrolyte solution is preferably solid, so that the electrolyte layer is not restricted by the inner casing. For good thermal and electrical properties, bonding layer 23 is preferred. In this configuration, the layers on the substrate are planar, resulting in a large contact area with the circuit carrier or substrate. Appropriate sealing is used for the power module to protect the capacitor terminals from environmental influences and to control the electric field.

[0076] In an embodiment, such as Figure 8 As shown, the substrate is connected to heat sink 4. In other embodiments, the substrate is a heat sink. This allows the capacitor to be cooled through the substrate and circuit carrier, and because all components from the aluminum buffer capacitor to the bonding layer have good thermal properties, this means optimal cooling of the capacitor is achieved due to the large surface area. The buffer capacitor requires high cooling because high voltage spikes and current generate heat. The advantage of the flat design of the capacitor is that it has a large surface area in contact with the circuit carrier, which can dissipate heat through the heat sink.

[0077] In some embodiments, the circuit carrier can be integrated as a wire junction between the capacitor and the power device, such that

[0078] This configuration ensures optimal utilization of the thermal properties of the aluminum capacitors within the power module. To adapt the capacitors to a specific power module, two or more capacitors can be connected in series. In this embodiment, this can be achieved by stacking the capacitors, such as... Figure 9 As shown. In this embodiment, a thermally conductive and electrically insulating layer 15 is preferably included. Alternatively, the stack can be arranged such that the anode layer of one capacitor precedes the anode layer of another capacitor, thereby inherently establishing a parallel connection.

[0079] This is necessary to ensure that the polarities are the same. As shown in the previous embodiment, the bonding layer can also be placed below the capacitor and connected to the circuit carrier. Then, it can be used... Figure 4 The concept connects the individual capacitors in the stack, allowing the layer to function as... Figure 12 The connection is shown. Connection point 26 can be made by welding, sintering, clamping, welding, riveting, ultrasonic welding, or other suitable methods. The top and bottom layers can also be connected to the substrate or circuit carrier by welding, riveting, ultrasonic welding, or other suitable methods. The bottom layer is connected to the circuit carrier by its extension, while the top layer can be connected to the circuit carrier by a connector.

[0080] Electrical insulator 22 is placed below the bottom layer to make the electrodes electrically insulated. In this embodiment, the same applies to the top layer, making the entire capacitor electrically insulated. Figure 11 As shown. All other non-insulating portions are preferably insulated in the same manner as the active devices on the circuit carrier. In embodiments, layer 22 may be the same as the bonding layer, but it may also be different from the bonding layer, because in some embodiments, particularly... Figure 12 In some embodiments, the bonding layer is conductive, i.e., non-insulating.

[0081] Alternatively, capacitors can be placed in series on a substrate and individually connected to a circuit carrier, allowing the circuit carrier to facilitate series or parallel connections between capacitors. These two approaches can also be combined, enabling capacitors to be delivered in different specifications.

[0082] To achieve good contact between the capacitor and the circuit carrier, in this embodiment, the capacitor is mechanically pressed onto the substrate using fasteners 16 (such as rivets, clamps, or springs). Figure 8 As shown. This ensures that the capacitor is adequately cooled during operation and can be electrically connected in this manner. In embodiments, this can also be achieved by soldering or sintering the capacitor to the circuit carrier. The bonding layer 23 is preferably placed below the bottom layer to facilitate bonding to the circuit carrier.

[0083] Figure 11 An advantageous embodiment of a single stacked capacitor is shown. In this embodiment, an electrical insulator 22, in the form of an electrical insulating layer, is placed beneath the bottom and top layers to electrically insulate the electrodes (i.e., the anode foil and the cathode foil). This must be done in such a way that voltage breakdown cannot occur. The insulating layer extends around all non-insulated portions of the capacitor, except for the areas used to electrically connect the capacitor to the circuit carrier.

[0084] In most embodiments, it is necessary to electrically insulate the capacitors on the circuit carrier. In some embodiments, this can be achieved through a capacitor housing (not shown).

[0085] This allows the electrodes to be pressed onto the circuit carrier or substrate. The anode foil and cathode foil are based on... Figure 4 Extending from this principle, this part of the foil is connected using a bonding layer that is both conductive and thermally conductive to provide a connection to the circuit carrier. This connection will be the only electrical connection, and all other parts of the capacitor are insulated using the same conventional principles used to insulate active devices in an insulated power supply module.

[0086] The capacitor is pressed onto a substrate or circuit carrier, allowing heat to dissipate from this layer into the substrate and further dissipate through an external heat sink. In some embodiments, the substrate is the heat sink, while in other embodiments, a separate heat sink is placed beneath the substrate. Figure 11 The design ensures that the capacitor has good electrical contact with the circuit carrier through (multiple) contact points 25, and good thermal contact with the circuit carrier at the bottom layer. The electrical insulation layer can also be configured as a separate enclosure around the capacitor. The main idea is that the enclosure or electrical insulation layer should be thermally conductive to utilize the thermal properties of the aluminum damping element, enabling effective cooling through the circuit carrier and substrate.

[0087] The insulating layer may be part of the anode foil or the cathode foil. In some embodiments, the insulating layer will also insulate all non-electrically insulated surface areas of the capacitor, such as... Figure 11 As shown. However, this can also be achieved through the capacitor casing. In some embodiments, the buffer capacitor is compatible with existing sealing technologies such as silicone, PU, ​​etc., for electrical insulation, corrosion protection, and dust contamination.

[0088] Although the invention has been described in conjunction with specific embodiments, it should not be construed as being limited in any way to the presented examples. The scope of the invention will be interpreted in accordance with the appended claims. In the context of the claims, the terms "comprising" or "including" do not exclude other possible elements or steps. Furthermore, references to words such as "a" or "an" should not be construed as excluding multiples. The use of reference numerals in the claims relating to elements indicated in the drawings should also not be construed as limiting the scope of the invention. Moreover, the various features mentioned in different claims are likely to be advantageously combined, and the mention of these features in different claims does not preclude the impossibility or disadvantage of such combinations.

[0089] Reference List

[0090] 1. Power Module

[0091] 1a. Power devices

[0092] 2. Circuit carrier

[0093] 3.Substrate

[0094] 4. Radiator

[0095] 5. Stacked aluminum electrolytic buffer capacitors

[0096] 6. Cathode layer

[0097] 7. Separator layer

[0098] 8. Anode layer

[0099] 9. Aluminum materials

[0100] 10. Dielectric

[0101] 11. Paper

[0102] 12. Electrolytes

[0103] 13. Power Module

[0104] 15. Insulation layer

[0105] 16. Fasteners

[0106] 17. Conductive traces

[0107] 18. Cathode foil

[0108] 19. Paper layer

[0109] 20. Anode foil

[0110] 21. Anode foil structure (etched channels)

[0111] 22. Electrical insulation

[0112] 23. Bonding layer

[0113] 24. Connector

[0114] 25. Contact point

[0115] 26. Connection point

Claims

1. A power module (1), the power module (1) comprising a power device (1a), a substrate (3), a circuit carrier (2), and a flat stacked aluminum electrolytic buffer capacitor (5), the stacked aluminum electrolytic buffer capacitor (5) comprising: - Hierarchical structure, including: - Cathode layer (6) - Separator layer (7), comprising paper (11) and electrolyte (12), and - Anode layer (8) contains aluminum material (9) having an alumina dielectric (10). The circuit carrier (2) is mounted on the substrate (3), and the power device (1a) and the buffer capacitor (5) are placed on the circuit carrier (2) within the power module and electrically connected to the circuit carrier by one or more conductive lines and one or more pads, such that the circuit carrier is configured to provide an electrical connection between the power device (1a) and the buffer capacitor (5).

2. The power module (1) according to claim 1, wherein, The stacked aluminum electrolytic buffer capacitor (5) is connected to the circuit carrier by an anode layer or a cathode layer disposed on the circuit carrier, and the corresponding cathode layer or anode layer is electrically connected to the circuit carrier via a connector (24).

3. The power module according to any one of the preceding claims, wherein, The bonding layer (23) is placed between the stacked aluminum electrolytic buffer capacitor (5) and the substrate (3) or circuit carrier (2).

4. The power module (1) according to any one of claims 1 or 3, wherein, The stacked aluminum electrolytic buffer capacitor (5) has a top layer, an intermediate layer and a bottom layer, the top layer being an anode layer or a cathode layer, the intermediate layer being a separator layer (7), and the bottom layer being a corresponding remaining cathode layer or anode layer, wherein the top layer extends in a direction in the plane defined by the layers so as to extend beyond the intermediate layer and the bottom layer, thereby being electrically connected to the circuit carrier.

5. The power module (1) according to claim 1 or 3, wherein, The anode layer or the cathode layer encapsulates the other layers of the stacked aluminum electrolytic buffer capacitor (5) into a can shape so that both the anode layer and the cathode layer are electrically connected to the circuit carrier for wireless bonding.

6. The power module according to claim 4, wherein the power module includes a bonding layer (23) disposed between the stacked aluminum electrolytic buffer capacitor (5) and the substrate (3) or circuit carrier (2), wherein, The bottom layer extends in a direction defined by the plane of the layer, which is different from the top layer, so as to extend beyond the bonding layer and thereby be electrically connected to the circuit carrier (2).

7. The power module (1) according to any one of the preceding claims, wherein, The substrate (3) also includes a heat sink (4), or is connected to an external heat sink (4).

8. The power module according to any one of the preceding claims, wherein, The electrolyte (12) is a polymer solution.

9. The power module (1) according to claim 3 or 6, wherein, If the capacitor is placed directly on the substrate, the anode layer (8) includes an anode foil (20), the cathode layer (6) includes a cathode foil (18), or the bonding layer is electrically insulated toward the substrate.

10. The power module (1) according to any one of the preceding claims, wherein, The capacitor is electrically insulated on all its non-insulated surfaces by covering its surface with a non-conductive material.

11. The power module (1) according to any one of the preceding claims, wherein, The channel (21) is etched in the aluminum material (9) so that the electrolyte (12) permeates the channel (21).

12. The power module (1) according to any one of the preceding claims, wherein, Two or more capacitors (5) are placed in series or in parallel by stacking the capacitors (5) and / or by arranging them on the circuit carrier.

13. The power module (1) according to claim 12, wherein, If the capacitors (5) are stacked, the power module includes an electrical insulating layer, and if the capacitors (5) are placed in series, the electrical insulating layer (15) is placed between the stacked capacitors.

14. The power module (1) according to any one of the preceding claims, wherein, The capacitor is mechanically pressed onto the substrate or circuit carrier by using fasteners (16).

15. The power module (1) according to any one of the preceding claims, wherein, The capacitor is configured to be welded, bonded with adhesive, or sintered to the circuit carrier.

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