Electrical assembly with capacitive elements

Abstract

To provide a method to facilitate assembling of capacitive elements with different heights into a casing.SOLUTION: In electrical equipment 100, a capacitive element 12, instead of being laid on studs at a bottom of a casing 11, comes in abutment on a top of the casing 11. A filling material 16 ensures holding of the capacitive element 12. Furthermore, the filling material 16 enables the capacitive element 12 to be electrically insulated and the capacitive element 12 to be sealed. The electrical equipment 100 has, between an electrical assembly 1 forming a capacitive block and a cooling circuit 20 which can be assembled to a chassis and comprises a cooling block 30, a thermal interface 40 with a controlled thickness. The thermal interface 40 consists of a flexible material providing a high thermal conductivity.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates in particular to an electrical assembly comprising a capacitive element and a casing, and more specifically to capacitive blocks.

[0002] The present invention aims in particular to improve the control of the manufacturing dimensions of such an electrical assembly, more specifically of capacitive blocks.

[0003] One advantage of the present invention is, more specifically in the field of electric motor systems for vehicles, to facilitate the assembly of such an electrical assembly into electrical equipment such as a power inverter.

[0004] The present invention aims in particular to enable an assembly adapted to the mass production of such electrical equipment.

Background Art

[0005] As is known, in a hybrid or electric vehicle, a high-voltage power battery has the function of supplying power to an electric motorization system that enables the vehicle to operate. For charging, for example, the high-voltage power battery is connected to an external power grid, in particular via a charger comprising at least one DC-DC voltage converter.

[0006] To control an electric machine that drives the wheels of a vehicle, it is known to use a power inverter that can convert the current supplied from a high-voltage power battery into one or more alternating currents, for example sinusoidal control currents.

[0007] The power inverter includes a capacitive block that allows the current supplied from the power battery to be smoothed before it is converted into an AC control current. The capacitive block includes a casing with a cavity into which capacitive elements are inserted, in particular to ensure current smoothing. Thus, these capacitive elements enable the removal of residual disturbances from the current and the conversion of this current into an AC control current. In the capacitive block, the capacitive elements are embedded in a filler, particularly a resin, within the casing to achieve sealing and electrical insulation of the capacitive elements. The capacitive block also has at least one output electrical connector to enable electrical connection between the capacitive elements and other electrical equipment. At least one electrical connector is welded to the capacitive elements, in particular. The electrical connector corresponds to a conductor, also called a lead chassis. Such an electrical connector is folded, for example, via a dedicated electrical connection bar to enable electrical connection between the capacitive elements and other electrical equipment.

[0008] The power inverter further comprises a power module configured to perform the conversion of current supplied from the battery into AC controlled current that is injected into the electromechanical device.

[0009] As is well known, in electrical components, capacitive elements can be placed within a casing and embedded in a filler that primarily serves to hold the capacitive elements and protect them from moisture. Such fillers are generally in the form of resin.

[0010] Electrical components equipped with such capacitive elements must be cooled to dissipate the heat emitted from them. Therefore, the electrical components are positioned opposite the cooling circuit.

[0011] In practice, referring to Figure 1 which represents the prior art, in such an electrical device 200, the capacitive element 112 is located within a casing 111 having a bottom, side walls, and an opening into which the capacitive element 112 is inserted. Studs 117 are attached to the bottom of the casing 111. The capacitive element 112 is positioned on these studs 117. On the opposite side, an electrical connector 113 of the capacitive element 112 is welded to the capacitive element 112. The capacitive element 112 is embedded in the filler material 116 of the casing 111, particularly a resin that seals the capacitive element and provides electrical insulation, and the filler material 116 is also called "potting".

[0012] The assembly 101, formed from a casing 111 and a capacitive element 112 to which an electrical connector 113 is attached, is positioned, via a side corresponding to an opening, opposite a cooling circuit 130 incorporated into the chassis 120 of the electrical component 200 that encloses the assembly 101, for example. To this end, the electrical assembly 101 is attached to the chassis 120 by a fitting means 115.

[0013] Therefore, in a conventional assembly process, the subassembly 101 forming the capacitive block is bolted, for example, to the main chassis, specifically to the chassis of the power inverter that supplies energy to the vehicle's electric motor.

[0014] As is well known, the thermal interface 140 is provided between the capacitive element 112 and the electrical connector 113 and the cooling circuit 130. Such a thermal interface 140 is made of a material with particularly high thermal conductivity. Its function is to improve the heat dissipation of the heat from the electrical connector 113 of the capacitive element 112 toward the cooling circuit 130. The thermal interface 140 is, in effect, a heat sink positioned in contact with the cooling circuit 130. Also, as is well known, the thickness of the thermal interface 140 is determined by predetermined dimensional requirements that are particularly relevant to the amount of heat to be dissipated during operation.

[0015] However, with respect to Figure 1, the prior art cannot fully control the upper level of the assembly 101, which comprises the casing 111 and the capacitive element 112, as is inherently related to the assembly process described above, particularly due to the different manufacturing tolerances of each component forming the assembly. More specifically, there is considerable variation in the height of the capacitive element 112.

[0016] However, as is known in the art, the height of the thermal interface 140 is determined by the dimensions of other components of the electrical assembly, specifically the capacitive blocks. In addition to the height of the capacitive elements 112, the height of the casing 111 and the height of the studs 117 in which the capacitive elements 112 are arranged have a particular influence.

[0017] Along with the inherent manufacturing tolerances of each of these elements, the actual thickness of the thermal interface can be as wide as 1.6 mm, potentially with significant variation. This variation E2 caused by the thickness of the thermal interface 140 is a major drawback, especially if the thermal interface 140 is very thin, in other words, very compressed, as this can lead to perforation and induce sealing loss in the electrical assembly 101. Similarly, if the thickness of the thermal interface 140 is very thick, the heat dissipation function will be poor.

[0018] However, in the prior art, most of the variation E2 in the thickness of the thermal interface 140 is due to the height of the capacitive block, or in other words, the height of the electrical assembly 101, which consists of the casing 111 and the capacitive elements 112 placed within the casing 111. Specifically, there is a large variation in the height of the capacitive elements 112 due to manufacturing tolerances, which leads to significant uncertainty in the height and thickness of the thermal interface in particular. Therefore, two capacitive elements of the same type corresponding to the same model can typically have different heights of less than 1 mm.

[0019] Therefore, there is a need for an electrical assembly that has capacitive elements placed within a casing, configured such that the height of the electrical assembly is controlled, and the level reached by the top of the capacitive elements on the opening side of the casing is controlled, while maintaining some flexibility in manufacturing dimensions and keeping the size to a minimum.

[0020] By meeting this need, the thickness of the thermal interface implemented between the capacitive element and its electrical connector and the cooling circuit of the chassis on which the assembly is positioned is also controlled.

[0021] To this end, an electrical assembly is provided, comprising a casing in which a capacitive element having an electrical connector is housed. According to the present invention, the casing comprises a shoulder portion located on the opening side, the shoulder portion abuts against and receives at least one electrical connector of the capacitive element. [Overview of the Initiative]

[0022] More precisely, the object of the present invention is an electrical assembly, specifically a capacitive block, comprising a capacitive element, at least one electrical connector fixed to the capacitive element, and a casing having a bottom, side walls, and an opening into which the capacitive element is inserted, wherein the casing has at least one shoulder on the opening side, the shoulder forming a stopper configured to abut and receive at least one electrical connector, and supporting the capacitive element.

[0023] It is advantageous for the capacitive elements to be embedded in the casing's filler material and mounted within the casing.

[0024] According to one embodiment, the shoulder portion is a rib that forms a longitudinal projection integral with the casing, the rib having an end recessed from the opening and forming a stopper configured to abut and receive at least one electrical connector.

[0025] According to one embodiment, at least one electrical connector has a thickness that is less than the distance between the shoulder and the opening.

[0026] According to one embodiment, the casing includes a cavity that can accommodate the entire capacitive element.

[0027] The present invention also relates to an electrical component comprising a cooling circuit and an electrical assembly as briefly described above, the electrical assembly being attached to the cooling circuit of the electrical component, particularly through an opening of the casing.

[0028] According to one embodiment, the electrical component is configured to be mounted on a vehicle and forms a power inverter configured to supply (electric power) from a battery to an electric motor driving the vehicle, or a DC-DC converter configured to convert a voltage between a high-voltage battery and a low-voltage battery, or a charger configured to convert a voltage between an external power grid of the vehicle and the vehicle's battery.

[0029] The present invention also relates to a method of manufacturing the assembly briefly described above, the manufacturing method comprising - attaching at least one electrical connector to at least one terminal of the capacitive element; - placing the capacitive element attached with the connector into the casing such that the connector abuts against the shoulder; - filling the casing with a fluid filler to fill at least a part or the whole of the space between the capacitive element and the casing; - particularly curing the filler by heating to attach the capacitive element to the casing.

[0030] It is advantageous for at least one electrical connector to be welded to the capacitive element on the opening side of the casing.

Brief Description of the Drawings

[0031] The present invention will be better understood by reading the following description with reference to the attached drawings given as non-limiting examples, where the same reference numerals in the drawings are used for similar objects. [Figure 1] This is a diagram of a device comprising an assembly having a casing and capacitive elements (as already described), and an electrical assembly having an electrical interface between the assembly and a chassis having a cooling circuit. [Figure 2] This is a diagram of a corresponding electrical assembly according to one embodiment of the present invention. [Figure 3] This shows a perspective view of the casing of an electrical assembly according to one embodiment of the present invention. [Figure 4] A perspective view of an electrical assembly according to one embodiment of the present invention is shown.

[0032] It should be noted that the drawings illustrate the invention in more detail for the purpose of carrying it out, and of course, can be used to better define the invention as needed. [Modes for carrying out the invention]

[0033] Without limiting the scope of the present invention in the following description, the present invention will be primarily described in relation to capacitive blocks, or at least, in relation to electrical components for vehicles, specifically electric or hybrid vehicles, that include capacitive elements provided within a casing.

[0034] The present invention also relates to an electrical component comprising a casing that at least partially encloses a capacitive element. Specific applications relate to capacitive blocks as described above, and these applications are not considered limiting.

[0035] The capacitive block also includes at least two connectors, specifically a connector corresponding to the negative terminal of the capacitive element and a connector corresponding to the positive terminal of the capacitive element. These connectors thus allow access to the positive and negative terminals of the capacitor for connecting the capacitive element to the rest of the system.

[0036] Other electrical components, particularly those for electric or hybrid vehicles, such as DC-DC voltage converters or chargers, may also have such capacitive blocks.

[0037] Figure 1 shows a schematic side view of a two-dimensional cross-section of the prior art electrical component 200. The electrical component 200 has already been described.

[0038] Referring to Figure 2, the capacitive element 12 abuts against the top of the casing 11 instead of being positioned on studs at the bottom of the casing 11. The filler 16 securely holds the capacitive element 12. Furthermore, the filler 16 can electrically insulate and seal the capacitive element 12. Thus, the electrical component 100 has a thermal interface 40 of controlled thickness between the electrical assembly 1 that forms the capacitive block and the cooling circuit 20 that can be incorporated into the chassis and constitute the cooling block 30. The thermal interface 40 is made of a flexible material exhibiting high thermal conductivity, such as a gap pad® type. Alternatively, the thermal interface 40 may be made of thermal grease.

[0039] According to one embodiment of the present invention, referring further to Figure 2, the stopper is formed to connect to the "upper part" of the coil 12, i.e., to at least one electrical connector 13 welded to the capacitive element 12 on the opening side of the casing 11, and to at least one shoulder portion 14 provided on the "upper part" of the casing 11, i.e., on the opening O side of the casing 11.

[0040] In particular, the manufacturing-related dimensional tolerances affecting the height of the thermal interface between the electrical connector 13 of the capacitive element 12 and the cooling circuit 20 depend solely on the thickness of at least one connector 13 and the height of the shoulder portion 14, i.e., the distance between the shoulder portion 14 and the opening O.

[0041] The stopper is provided at the top of the casing 11, and the casing 11 can also be a casing in which the entire capacitive element 12 is housed.

[0042] The contact of the connector 13 on at least one shoulder 14 allows the capacitive element 12 to be supported by at least one shoulder 14, rather than by the bottom of the casing 11, as in the prior art. A space remains between the lower end of the capacitive element 12, i.e., the side opposite the opening O of the casing 11, and the bottom of the casing 11. This space can accommodate uncertainty regarding the height of the capacitive element 12, thereby maintaining the upper part of the capacitive block 12 at the same level regardless of variations in the height of the capacitive element 12 with respect to the nominal height.

[0043] According to one embodiment, the casing is made of a conductive material such as aluminum. In this case, an electrical insulating sheet is additionally placed between the capacitive element 12 and its electrical connector 13 and the casing. Thus, for example, the electrical assembly is part of an electrical component such as a power inverter, and the casing is the cover of the power inverter.

[0044] According to one embodiment, the casing 11 is made of plastic and does not require the provision of an additional electrical insulating sheet.

[0045] Figures 3 and 4 show a casing 11 of an electrical assembly according to one embodiment of the present invention and such an electrical assembly 1, respectively, in which a capacitive element 12 is housed within the casing 11, and at least one electrical connector 13, which is disposed on a shoulder portion 14 provided on the upper part of the casing 11, is welded to the upper part of the capacitive element 12, i.e., the opening side of the casing 11.

[0046] As shown in the figure, according to the present invention, the variation E1 potentially determined by the thickness of the thermal interface 40 is reduced to ±0.5 mm compared to ±1.6 mm in the case of Figure 1, which represents the prior art, due to equal manufacturing tolerances of the mechanical parts.

[0047] As shown in Figures 3 and 4, the shoulder portion 14 is a rib that forms a longitudinal projection within the casing 11, for example. The capacitive element 12 is provided to be inserted into the cavity of the casing 11. An electrical connector 13, welded to the capacitive element 12, is positioned to abut against the shoulder portion 14. Specifically, the capacitive element 12 is then embedded in a filler, particularly a resin, that occupies the entire usable capacity of the casing 11. Upon curing, the filler holds the capacitive element 12 in place within the casing 11. According to one embodiment, the filler does not completely surround the capacitive element, but covers only a portion of it, sufficient to securely hold the capacitive element.

[0048] The electrical assembly 1 configured in this way can then be positioned, for example, opposite a cooling circuit. Specifically, referring to Figure 2, the electrical assembly 1 is configured to be positioned opposite a chassis containing a cooling circuit 20. A thermal interface 40, which has the function of improving heat dissipation, is interposed between the electrical connector 13 of the capacitive element 12 and the cooling circuit 20.

[0049] The electrical assembly 1 is provided to be attached to the cooling circuit 20 by the fitting means 15, so that the electrical assembly 1 and the cooling circuit 20 are in plane-plane contact with each other, and the thickness of the thermal interface 40 is subjected to stress. However, according to the present invention, the thickness of the thermal interface 40 is controlled with improved precision compared to the prior art, and the thickness of the thermal interface 40 is affected only by the manufacturing tolerances relating to the height of the shoulder portion 14 and the thickness of the electrical connector 13 of the capacitive element 12.

[0050] In particular, the uncertainty in the manufacturing tolerance regarding the height of the capacitive element 12 no longer affects the thickness of the thermal interface 40. Furthermore, studs for receiving the capacitive element 12 are not required at the bottom of the casing 11.

[0051] According to one embodiment, the electrical assembly can be mounted, in particular, on a chassis cover using guide studs provided on the cover, forming an assembly with the cover, and then assembled, in particular, onto a chassis that includes a cooling circuit. In this case, the cover corresponds to the "casing" of the electrical assembly and partially or completely encloses the capacitive elements.

Claims

1. An electrical component comprising a cooling circuit (20) and an electrical assembly (1), The device comprises a capacitive element (12), at least one electrical connector (13) fixed to the capacitive element (12), and a casing (11) having a bottom, side walls, and an opening into which the capacitive element (12) is inserted, wherein the casing (11) has at least one shoulder portion (14) on the opening side, and the shoulder portion (14) forms a stopper configured to abut and support the at least one electrical connector (13) from below, thereby supporting the weight of the capacitive element (12). The electrical assembly is attached to the cooling circuit (20) of the electrical component. A thermal interface (40) having a controlled thickness is provided between the at least one electrical connector (13) of the capacitive element (12) and the cooling circuit (20). An electrical component wherein a portion of the thermal interface (40) is positioned on the portion of the electrical connector (13) that is positioned on the shoulder portion (14).

2. The electrical component according to claim 1, wherein the capacitive element (12) is embedded in the filler material (16) of the casing (11), and the capacitive element (12) is mounted inside the casing (11).

3. The electrical component according to claim 1 or 2, wherein the shoulder portion (14) is a rib that forms a longitudinal projection integral with the casing (11), and the rib has an end portion recessed from the opening and forms the stopper configured to abut and support the at least one electrical connector (13) from below.

4. The electrical component according to any one of claims 1 to 3, wherein the at least one electrical connector has a thickness less than the distance between the shoulder portion and the opening.

5. The electrical component according to any one of claims 1 to 4, wherein the casing (11) has a cavity capable of housing the entire capacitive element (12).

6. The electrical component according to any one of claims 1 to 5, wherein the electrical component is configured to be mounted on a vehicle and forms a power inverter configured to supply power from a battery to an electric motor that drives the vehicle, or a DC-DC converter configured to convert voltage between a high-voltage battery and a low-voltage battery, or a charger configured to convert voltage between an external power system of the vehicle and the battery of the vehicle.

7. The steps include attaching at least one electrical connector (13) to at least one terminal of the capacitive element (12), The steps include: positioning the capacitive element (12) attached to the connector (13) inside the casing (11) such that the connector (13) abuts against and is supported by the shoulder portion (14) from below; The steps include filling the casing (11) with a fluid filler to fill at least part or all of the space between the capacitive element (12) and the casing (11), A method for manufacturing an electrical component according to any one of claims 1 to 6, further comprising the step of hardening the filler by heating and attaching the capacitive element (12) to the casing (11).

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