Electronic module for a power module, power module and method for producing a power module

Abstract

The invention relates to an electronic module (EM) for arrangement on a printed circuit board (LP) of a power module (LM) for a motor vehicle, comprising a plurality of electrical components (EB) arranged at a distance from one another and potted at least in sections, in which at least one intermediate space (ZR) is potted with an electrically insulating potting material (VM), and the plurality of electrical components (EB) potted together form a unit that can be arranged on a printed circuit board (LP) or connected to a printed circuit board (LP).

Description

[0001] The invention relates to an electronic module for a power module, which is preferably used for high-voltage technology in a motor vehicle. The electronic module comprises a plurality of electrical components that are combined into a unit via a potting material and can thus be arranged on a circuit board. The potting material allows the electrical components of the electronic module to have a reduced distance from one another while still exhibiting increased dielectric strength. The invention also relates to a power module with the electronic module according to the invention. The invention further relates to a method for producing the power module.

[0002] Power modules are generally well-known. These power modules typically feature individual electrical components thermally bonded to a cooling surface. An electrical insulation film is arranged between the cooling surface and the electrical components, particularly in high-voltage applications, preferably with SiC MOSFETs. The insulation film requires precise processing and placement to prevent partial electrical breakdown. Furthermore, the electrical components must maintain a certain minimum distance from each other to prevent electrical flashover between the components.

[0003] An object of the invention is to provide an electronic module for a power module or a power module which can have a reduced installation space and a reduced risk of partial electrical breakdown, and which is inexpensive to manufacture and easy to assemble.

[0004] This problem is solved by the subject matter of the independent patent claims. Preferred developments of the invention are the subject matter of the dependent patent claims, the following description, and the drawings. Each feature can represent an aspect of the invention, both individually and in combination, unless explicitly stated otherwise in the description.

[0005] In a first aspect of the invention, it is provided that an electronic module is provided for arrangement on a circuit board of a power module for a motor vehicle, comprising a plurality of electrical components arranged at a distance from one another and potted at least in sections, in which at least one intermediate space is potted with an electrically insulating potting material, and the plurality of electrical components potted together form a unit that can be arranged on a circuit board or connected to a circuit board.

[0006] In other words, according to the first aspect of the invention, an electronic module is provided for arrangement on a circuit board of a power module. The power module is preferably used in an at least partially electrically powered motor vehicle. The electronic module comprises a plurality of electrical components arranged at a distance from one another. An electrical component is preferably, but not limited to, a transistor or a diode. The transistor can preferably be a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT). In particular, the electrical components can comprise GaN (gallium nitride) or SiC (silicon carbide) semiconductor materials.

[0007] The modules are encapsulated at least in sections with an electrically insulating encapsulation material, wherein at least it is provided that the encapsulation material is arranged in a space between the electrical modules. By arranging the encapsulation material in the space between the electrical modules, the dielectric strength between the electrical modules can be increased and the distance between the electrical modules can be reduced, which can have a beneficial effect on the installation space of the electronic module. The encapsulation of the electrical modules at least in sections also includes the variant in which preferably several sides of the electrical modules are encapsulated. It is also conceivable for the electrical modules to be completely encapsulated with the electrically insulating encapsulation material and for only one contact element of the electrical module to be exposed or to be led out of the encapsulation material.If multiple sides of the electrical components are encased in the electrically insulating potting material, the dielectric strength of adjacent components can be increased. By encapsulating the electrical components with the potting material, they are bonded together to form a single unit. The unit can be easily and inexpensively arranged on the circuit board and / or electrically connected to the circuit board. It is also conceivable for the unit to be mounted on a cooling device.

[0008] An advantageous development of the invention is that the electrically insulating encapsulating material is a plastic or at least partially made of plastic. A plastic has enhanced electrically insulating properties. Furthermore, a plastic is inexpensive to produce and easy to process, allowing the electronic module to be manufactured simply and inexpensively.

[0009] The plastic is preferably, but not limited to, a thermosetting material. It is particularly advantageous for the plastic to be an epoxy-based thermosetting material. Thermosetting materials have the advantageous property of being temperature-stable, which can be particularly necessary when the electrical components, preferably, experience elevated temperatures or the electronic module is exposed to elevated temperatures.

[0010] It's conceivable that the plastic material could be filler-free. Such a plastic is particularly inexpensive and easy to produce.

[0011] Alternatively, an advantageous development of the invention is that the plastic contains a filler. The filler acts like a reinforcement. In addition to improving the structural properties of the encapsulation, the filler in the plastic can also increase the electrical breakdown strength.

[0012] In this context, an advantageous development of the invention is that the filler is a ceramic-based and / or glass-based filler. The glass-based filler is preferably, but not limited to, a silicate glass. A ceramic or glass filler, in addition to high electrically insulating properties, also has strength-enhancing properties. This allows the thickness of the potting material to be reduced, which can result in space- and / or weight-reducing advantages.

[0013] The filler content is preferably between 50% and 90% by volume, in particular between 60% and 85% by volume, and particularly preferably between 70% and 88% by volume. Such a high filler content can, in particular, increase the structural rigidity of the potting material.

[0014] A particularly advantageous development of the invention is that the potting material is pore-free. This pore-free design of the potting material allows for increased electrical breakdown power.

[0015] In a preferred embodiment of the invention, the electrical components are different from one another. In other words, one electrical component can be a diode, while another component in the electronic module is a transistor.

[0016] Alternatively, it can advantageously be provided that the electrical components are identical. In other words, a plurality of identical electrical components, i.e., exclusively diodes or exclusively transistors, are arranged in an electronic module. Typically, the same components also experience a comparable temperature increase at the same time, so that the electronic module is heated evenly, or this heat can then be dissipated accordingly.

[0017] An advantageous embodiment of the invention is that the following applies to the smallest distance a between two electrical components: 0.1 mm ≤ a ≤ 2 mm; preferably 0.2 mm ≤ a ≤ 1.5 mm, and particularly preferably 0.3 mm ≤ a ≤ 1 mm. In this way, an electronic module can be provided that has reduced dimensions. An electronic module with reduced dimensions can also have a reduced weight.

[0018] In a second aspect, the invention relates to a power module for a high-voltage device in a motor vehicle, comprising a printed circuit board, an electronic module according to the invention electrically connected to the printed circuit board, and a cooling device thermally connected to the electronic module.

[0019] In other words, according to the second aspect of the invention, the electronic module according to the invention is integrated into a power module, wherein the power module is a component of a high-voltage device. A high-voltage device can preferably be, but is not limited to, an inverter or an intelligent charging system (HV box). The HV box preferably comprises, but is not limited to, a DC / DC converter and / or an integrated charger (onboard charger). The onboard charger preferably comprises a controller for uniformly and / or gently charging battery cells. High voltage comprises an alternating voltage of greater than 30 volts and a direct voltage of greater than 60 volts. The high-voltage device is intended for use in a motor vehicle.

[0020] The power module comprises at least one circuit board and the electronic module according to the invention, wherein the electronic module is electrically connected to the circuit board. Furthermore, it is provided that the electronic module is thermally connected to a cooling device. As described above in this disclosure, the electronic module according to the invention can have reduced dimensions and increased electrical breakdown power. The thermal connection of the electronic module to the cooling device allows the heat generated in the electrical components to be dissipated, thereby increasing the performance of the power module and reducing thermally induced failures of the power module.

[0021] In a preferred embodiment of the invention, a thermal interface material (TIM) is arranged between the electronic module and the cooling device. The thermal interface material can preferably be a compressible pad. Tolerances can be compensated via the thermal interface material, thus enabling increased thermal connection between the electronic module and the cooling device. The increased thermal connection can increase the performance of the power module.

[0022] An advantageous development of the invention is that the electronic module has the electrically insulating encapsulating material on a side facing the circuit board. By designing the electronic module in such a way that it also has the electrically insulating encapsulating material, preferably over its entire surface, on the side facing the circuit board, the electrical breakdown force between the electronic module and the circuit board can be increased, thereby increasing the operational reliability of the electronic module in high-voltage applications.

[0023] In a preferred embodiment of the invention, the electronic module comprises the electrically insulating encapsulating material on a side facing the cooling device. Thus, the electronic module comprises the electrically insulating encapsulating material between the electrical component and the cooling device. The encapsulating material between the electrical components and the cooling device can increase the electrical breakdown force between the electronic module and the cooling device.

[0024] Alternatively, the electronic module can be designed without any encapsulation material on a side facing the cooling device, and an electrical insulation layer (film) can be formed between the cooling device and the electrical components. In other words, the electrical component can be designed without any encapsulation material on a side facing the cooling device. This may be necessary in some cases where a stronger thermal connection between the electrical components and the cooling device is required.

[0025] An electrically insulating layer, in particular a film or a coating, is then applied between the electrical component and the cooling device in order to ensure the electrical breakdown force between the electrical components and the cooling device.

[0026] Furthermore, it is provided that the thermal intermediate layer or the thermal interface material is preferably arranged between the electrically insulating layer and the electrical components, so that an increased thermal connection of the electrical components to the cooling device is achieved.

[0027] It is conceivable that the electronic module is arranged on the circuit board.

[0028] Advantageously, the circuit board is connected to the electronic module by a material-to-material, form-fitting, and / or friction-locking connection. The material-to-material connection is preferably an adhesive connection. The form-fitting connection is preferably a clamp connection. The friction-locking connection is preferably a screw connection. In this way, the electronic module can be attached to the circuit board in a simple and cost-effective manner.

[0029] An advantageous development of the invention is that the electronics module is clamped between the circuit board and the cooling device. In other words, an air cushion between the circuit board and the electronics module on the one hand, and the electronics module and the cooling device on the other, can be avoided, thereby enabling a greater thermal connection between the electronics module and the circuit board and the cooling device. Vibrations in the power module can also be minimized.

[0030] In a third aspect, the invention relates to a method for producing the power module according to the invention with the electronic module according to the invention, comprising the steps: - Providing the circuit board; - Contacting the electronic module with the circuit board; and - Thermal connection of the electronic module to the cooling system.

[0031] In other words, according to the third aspect of the invention, a printed circuit board is provided. The electronic module according to the invention is electrically conductively connected to the printed circuit board, in particular to a conductor track of the printed circuit board. Furthermore, the electronic module is thermally conductively connected to the cooling device. Due to the thermal connection of the electronic module to the cooling device, heat generated in the electronic module can be dissipated, which can have a positive effect on the performance of the power module. Since the electrical components in the electronic module according to the invention are arranged in an electrically insulating potting, the dielectric strength can be increased.

[0032] It should be noted that all features described above and below with respect to one aspect of the present invention equally apply to any other aspect of the present invention. In particular, all features of the electronic module can also be features of the power module and the method for manufacturing the power module. This also applies vice versa.

[0033] Further features and advantages of the present invention emerge from the dependent claims and the following exemplary embodiments. The exemplary embodiments are not limiting, but rather are to be understood as examples. They are intended to enable the skilled person to implement the invention. The applicant reserves the right to make individual and / or several of the features disclosed in the exemplary embodiments the subject of patent claims or to incorporate such features into existing patent claims. The exemplary embodiments are explained in more detail with reference to drawings.

[0034] In these show: Fig. 1 a plan view of an electronic module in a first embodiment; Fig. 2 a longitudinal section through a power module in a first embodiment with the electronic module of the first embodiment; Fig. 3 a longitudinal section through the power module in a second embodiment with the electronic module of the first embodiment; Fig. 4 a plan view of the electronic module in a second embodiment Fig. 5 a cross section through the power module in a third embodiment with the electronic module of the second embodiment; Fig. 6 a cross section through the power module in a fourth embodiment with the electronic module of the second embodiment; Fig. 7 a cross section through the power module in a fifth embodiment with the electronic module of the second embodiment.

[0035] In Fig. Figure 1 shows a top view of an electronic module EM for arrangement on a printed circuit board LP of a power module LM in a first embodiment. The electronic module EM comprises a plurality of electrical components EB arranged at a distance from one another. An electrical component EB is preferably, but not limited to, a transistor or a diode. The transistor can preferably be a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT).

[0036] The electrical components EB are encapsulated at least in sections with an electrically insulating encapsulating material VM, wherein at least provision is made for the encapsulating material VM to be arranged in a gap ZR between the electrical components EB. By arranging the encapsulating material VM in the gap ZR between the electrical components EB, the dielectric strength between the electrical components EB can be increased and a distance a between the electrical components EB can be reduced, which can have an advantageous effect on the installation space of the electronic module EB. The encapsulation of the electrical components EB at least in sections also includes the variant in which preferably several sides of the electrical components EB are encapsulated.It is also conceivable that the electrical components EB are completely encapsulated with the electrically insulating encapsulating material VM and that one or more contact elements KE of the electrical component EB are led out of the encapsulating material VM.

[0037] If multiple sides of the electrical components (EB) are encapsulated with the electrically insulating encapsulating material (VM), the dielectric strength of adjacent components can be increased. Encapsulating the electrical components (EB) connects them to form a single unit. This unit can be easily and inexpensively arranged on the printed circuit board (LP) and / or electrically connected to the printed circuit board (LP).

[0038] Fig. 2 shows a longitudinal section through the power module LM in a first embodiment with the electronic module EM of the first embodiment.

[0039] The power module LM is preferably a component of a high-voltage device. A high-voltage device can preferably be, but is not limited to, an inverter or a high-voltage box (HV box). The HV box preferably includes, but is not limited to, a DC / DC converter and / or an integrated charger (onboard charger). The onboard charger preferably includes a controller for uniformly and / or gently charging battery cells. High voltage includes an AC voltage greater than 30 volts and a DC voltage greater than 60 volts. The high-voltage device is intended for use in a motor vehicle.

[0040] The power module LM comprises at least one printed circuit board LP and the electronics module EM, wherein the electronics module EM is electrically connected to the printed circuit board LP via the contact elements KE of the electrical components EB. Furthermore, the electronics module EM is thermally connected to a cooling device KUE. The electronics module EM has the electrically insulating encapsulation material VM on a side facing the printed circuit board LP. In other words, the encapsulation material VM is formed on an upper side OS of the electrical components EB, which faces the printed circuit board LP, so that the electrical components EB are indirectly in contact with the printed circuit board LP via the encapsulation material VM.By designing the electronic module EB in such a way that it additionally has the electrically insulating potting material VM, preferably over its entire surface, on the side facing the printed circuit board LP, the electrical breakdown force between the electronic module EM and the printed circuit board LP can be increased, whereby the operational reliability of the electronic module EM can be increased, preferably in the area of ​​high-voltage applications.

[0041] Furthermore, it can be seen that the electronic module EM is designed without any potting material on a side facing the cooling device KUE, and an electrical insulation layer EI (foil) is formed between the cooling device KUE and the electrical components EB. In other words, it is provided that the electrical component EB has no potting material on a side facing the cooling device KUE. This may be necessary in some cases where a stronger thermal connection between the electrical components EB and the cooling device KUE is required. The electrical breakdown force is ensured via the electrical insulation layer EI. Furthermore, it is provided that a thermal interface material TIM is arranged for the increased thermal connection between the electronic module EM and the cooling device KUE. The thermal interface material TIM can preferably be a compressible pad.The thermal interface material TIM can be used to compensate for tolerances, enabling increased thermal connection between the EM electronics module and the KUE cooling unit. This increased thermal connection can increase the performance of the LM power module.

[0042] Fig. Figure 3 shows a longitudinal section through the power module LM in a second embodiment with the electronic module EM of the first embodiment. In contrast to the Fig. 2, the power module LM has in Fig. 3 no electrical insulation layer EI between the electrical components EB and the cooling device KUE. Instead of the electrical insulation layer EI, it is provided that the electronic module EM has the electrically insulating potting material VM on a side facing the cooling device KUE. It is thus provided that the electronic module EM has the electrically insulating potting material VM between the electrical component EB and the cooling device KUE. In particular, it is provided that the potting material VM is applied to an underside US of the electrical components EB, which is arranged or formed at a distance from the upper side OS of the electrical components EB. The electrical breakdown force between the electronic module EM and the cooling device KUE can be increased by means of the potting material VM between the electrical components EB and the cooling device KUE.

[0043] In Fig. Figure 4 shows a top view of the electronic module EM in a second embodiment. In contrast to the first embodiment, as shown in Fig. As shown in Figure 1, the electrical components EB are arranged side by side in a row. This arrangement or design of the electrical components EB can offer advantages in terms of installation space.

[0044] In Fig. 5 is a cross-section through the power module LM in a third embodiment with the electronic module EM of the second embodiment. The electronic module EM is formed on the underside US of the electrical components EB without any potting material and is thermally connected to the cooling device KUE via the thermal interface material TIM. The electrical insulation layer EI is formed between the underside US of the electrical components EB and the thermal interface material TIM. The electrically insulating potting material VM is formed on an end face ST of the electrical components EB, which faces the printed circuit board LP and is aligned at a right angle to the underside US. The contact elements KE protrude from the end face ST and are guided through the potting material VM to the printed circuit board LP.

[0045] The potting material VM further comprises a fastening section BA through which a fastening means BM is guided in order to fasten the electronic module EM to the cooling device KUE in a force-fitting and form-fitting manner.

[0046] Fig. Figure 6 shows a cross section through the power module LM in a fourth embodiment with the electronic module EM of the second embodiment. In contrast to the Fig. The power module LM shown in Figure 5 has Fig. The LM power module shown in Figure 6 applies the encapsulation material VM to the underside US of the electrical components EB, rather than the thermal interface material TIM and the electrical insulation layer EI. The EM electronic module is firmly bonded to the cooling device KUE via a thermally conductive adhesive. This eliminates the need for a mounting section, which can have a beneficial effect on the installation space and weight of the LM power module. The front face ST of the electrical components EB is also designed without encapsulation material.

[0047] In Fig. Figure 7 is a cross-section through the power module LM in a fifth embodiment with the electronic module EM of the second embodiment. In contrast to Fig. 6 is in Fig.7, the electronic module EM is configured such that it is formed on two sides of the cooling device KUE. In other words, the electronic module EM has a U-shaped cross-section, and the cooling device KUE protrudes between the long upright webs of the U-shaped electronic module and is thermally connected to the electronic module EM. In this way, the component density can be increased, which can have a beneficial effect on the installation space of the power module LM.

Claims

[1] Electronic module (EM) for arrangement on a printed circuit board (LP) of a power module (LM) for a motor vehicle, comprising a plurality of electrical components (EB) arranged at a distance from one another and potted at least in sections, in which at least one intermediate space (ZR) is potted with an electrically insulating potting material (VM), and the plurality of electrical components (EB) potted together form a unit that can be arranged on a printed circuit board (LP) or connected to a printed circuit board (LP). [2] Electronic module according to claim 1, characterized by that the electrically insulating potting material (VM) is a plastic or at least partially contains plastic. [3] Electronic module according to claim 2, characterized by that the plastic is an epoxy-based thermoset. [4] Electronic module according to one of the preceding claims, characterized by that the casting material (VM) is pore-free. [5] Electronic module according to one of the preceding claims, characterized by that the electrical components (EB) are different from each other. [6] Electronic module according to one of claims 1 to 4, characterized by that the electrical components (EB) are the same. [7] Electronic module according to one of the preceding claims, characterized by that for a smallest distance a between two electrical components EB the following applies: 0.1 mm ≤ a ≤ 2 mm. [8] Power module (LM) for a high-voltage device in a motor vehicle, comprising a printed circuit board (LP), an electronic module (EM) according to one of the preceding claims which is electrically connected to the printed circuit board (LP), and a cooling device (KUE) which is thermally connected to the electronic module (EM). [9] Power module according to claim 8, characterized by that a thermal interface material (TIM) is arranged between the electronic module (EM) and the cooling device (KUE). [10] Power module according to one of claims 8 or 9, characterized by that the electronic module (EM) has the electrically insulating potting material (VM) on a side facing the printed circuit board (LP). [11] Power module according to one of claims 8 to 10, characterized by that the electronic module (EM) has the electrically insulating potting material (VM) on a side facing the cooling device (KUE). [12] Power module according to one of claims 8 to 10, characterized by that the electronic module (EM) is designed without any encapsulation material on a side facing the cooling device (KUE), and an electrical insulation layer (EI) is formed between the cooling device (KUE) and the electrical components (EB). [13] Power module according to one of claims 8 to 12, characterized by that the printed circuit board (LP) is connected to the electronic module (EM) in a material-locking, form-locking and / or force-locking manner. [14] Power module according to one of claims 8 to 13, characterized by that the electronic module (EM) is clamped between the printed circuit board (LP) and the cooling device (KUE). [15] Method for producing a power module (LM) according to one of claims 8 to 14 with an electronic module according to one of claims 1 to 7, comprising the steps: - Providing the printed circuit board (PCB); - Contacting the electronic module (EM) with the printed circuit board (LP); and - Thermal connection of the electronic module (EM) to the cooling unit (KUE).

Images