Electronic module, associated electronic system, mold and manufacturing method

Abstract

The invention relates to an electronic module (1) comprising:-a power assembly comprising:-a power board and-at least one electrically conductive track (102); a signal board (11) mounted on the power board; -at least one electrically conductive connection device (12) comprising a first face (121) and a second face (122) parallel to each other and connected by an elastic deformation means (123), the first face being connected to the signal plate; and-a housing (13) encapsulated on the power component, the signal plate and the at least one connection device, wherein:-the second face of the at least one connection device is flush with the outer surface of the housing; -the at least one connecting device is compressed in a direction perpendicular to the first and second faces of the connecting device.

Description

Technical Field

[0001] This invention relates to the field of power electronics, and more particularly, to the field of power supply equipment for electric motors. More specifically, this invention relates to electronic modules, molds configured to overmold or encapsulate such modules, methods for manufacturing electronic modules, and associated electronic systems.

[0002] This invention can be applied, for example, to electronic systems used in traction inverters, on-board chargers, electric cooling pumps for batteries, heat pumps, laser sensors for autonomous driving, etc. Background Technology

[0003] Electronic modules typically include contacts for connecting to auxiliary printed circuit boards (such as inverter control boards). These contacts allow signals, such as control signals, to be transmitted between the electronic module and the auxiliary printed circuit board.

[0004] These contacts are typically formed by press-fit pins. This type of contact consists of electrical pins that are pressed into sleeves on the electronic module using either soft solder or hard solder. These contacts are connected to the printed circuit board via a press-fit connection.

[0005] Problems can arise when electronic modules are subjected to stresses such as strong vibrations and / or high temperatures. In fact, under these conditions, electrical pins tend to detach from the sleeve due to vibration or expansion.

[0006] One object of the present invention relates in particular to overcoming all or some of the disadvantages of the prior art by providing a solution that provides a reliable electrical contact device. Summary of the Invention

[0007] Therefore, the object of the present invention is an electronic module comprising:

[0008] - Power component, which includes:

[0009] - Power board; and

[0010] - At least one conductive track;

[0011] Signal board mounted on power board;

[0012] - At least one conductive connection device, the connection device comprising a first surface and a second surface that are parallel to each other and connected by an elastic deformation device, the first surface being connected to a signal board;

[0013] - A housing overmolded over the power components, signal board, and at least one of the connection devices, wherein:

[0014] - At least one connecting device has a second surface flush with the outer surface of the housing; and

[0015] - At least one connecting device is compressed in a direction perpendicular to the first and second surfaces of the connecting device.

[0016] The electronic module may also include one or more of the following features, either individually or in combination of all technically possible features:

[0017] - At least one elastic deformation device of the connecting device is arranged to ensure the parallelism of the first and second surfaces during deformation of the device in a direction perpendicular to the surfaces of the first and second surfaces; and / or

[0018] - At least one connecting device has at least one notch on its first side to facilitate its connection with a signal board; and / or

[0019] - At least one connecting device includes a folded strip of conductive material, the strip including at least one recess near at least one fold, particularly forming an angle between 20° and 95°; and / or

[0020] - The strip includes multiple folds, particularly folds between two and four; and / or

[0021] - The strip includes at least one recess near each fold; and / or

[0022] - Each recess has the same shape; and / or

[0023] -At least one connecting device includes a folded strip of conductive material;

[0024] - The strip includes at least one reduced portion in the cross-section of the strip near at least one bend; and / or

[0025] - The electronic module includes at least two connection devices, particularly at least three connection devices, particularly at least five connection devices; and / or

[0026] - Each connection device is aligned in a direction perpendicular to the edge of the signal board; and / or

[0027] - All connection modules are aligned with each other; and / or

[0028] - At least one connecting device is shaped to an S-shape, Z-shape, C-shape or Σ-shape; and / or

[0029] - At least one of the first sides of the connecting device is connected to the signal board via means for conductive bonding, soft soldering, or hard soldering; and / or

[0030] - At least one connection device is configured to transmit electrical control signals; and / or

[0031] - The casing is covered with epoxy resin; and / or

[0032] - At least one conductive track of the electronic module includes a first portion having a flat shape and a second portion having a three-dimensional shape, the second portion of the conductive track including a connection pad forming the free end of the track, the connection pad of the second portion of the conductive track being flush with the outer surface of the housing; and / or

[0033] - Within the meaning of this application, parallelism extends across an angle difference of less than 5 degrees. It should be noted that the first and second faces may have mutually non-zero angles before assembly, for example, in the range of 2 to 4 degrees, specifically equal to 3 degrees; and / or

[0034] - At least one connection device is configured to transmit electrical control signals.

[0035] Another object of the present invention is a mold configured to encapsulate a housing within a power component, signal board, and at least one connection device of an electronic module according to the present invention, the at least one connection device comprising a first surface and a second surface, the first surface and the second surface being parallel to each other and connected to each other by an elastic deformation device, the mold being configured to define at least one outer surface of the housing and to mate with the second surface of the at least one connection device.

[0036] The mold may also include one or more of the following features, either individually or in combination of all technically possible features:

[0037] - The mold includes at least one recess configured to mate with a second surface of at least one connecting device, the at least one recess having a shape that matches the shape of the second surface of the at least one connecting device; and / or

[0038] - At least one recess engages with the second surface of at least one connecting device by compression in a direction perpendicular to the second surface.

[0039] Another object of the present invention is a method for manufacturing an electronic module according to the present invention, comprising the following steps:

[0040] - Provide at least one signal board;

[0041] - Provide at least one connecting device, the at least one connecting device comprising a first surface and a second surface that are parallel to each other and connected to each other by an elastic deformation device, the elastic deformation device being arranged to ensure the parallelism of the first surface and the second surface during deformation of the device;

[0042] - Connect the first side of at least one connection device to at least one signal board;

[0043] - Provide at least one mold according to the invention;

[0044] - Apply the mold to contact the second side of at least one connecting device;

[0045] - A mold is used to deform the elastic deformation device of at least one connecting device by compression; the compressive force of each connecting device can be in the range of 100N and 200N;

[0046] - Inject resin into a mold to encapsulate the housing within the power component, at least one signal board, and at least one connection device.

[0047] The method may also include one or more of the following features, considered individually or in combination of all technically possible features:

[0048] - The mold includes at least one recess, the at least one recess being configured to mate with the second surface of at least one connecting device; and / or

[0049] -The method also includes the step of cleaning the second side of at least one connection device; and / or

[0050] - The cleaning process is performed by deburring and / or by laser ablation, especially if the residual thickness is high.

[0051] Another object of the present invention is an electronic system comprising at least one electronic module according to the invention and an interconnect comprising a plurality of tabs, wherein each tab is connected to a second side of a connecting device.

[0052] The electronic module of the electronic system may also include a first positioning element that defines a reference position on the electronic module, and the interconnect may include a second positioning element configured to cooperate with the first positioning element. Attached Figure Description

[0053] The invention will be better understood from the following description in the context of electronic modules, associated electronic systems, molds, and manufacturing methods. This description is provided for illustrative purposes only and is not intended to limit the invention, and is accompanied by the following figures:

[0054] [ Figure 1 [Illustration] is a schematic diagram of an embodiment of the electronic module according to the present invention;

[0055] [ Figure 2 [Illustration] is a schematic diagram of a specific embodiment of an electronic module according to the present invention;

[0056] [ Figure 3 [Illustration] is a schematic diagram of an embodiment of the connection device according to the present invention;

[0057] [ Figure 4 [Illustration 1] is a schematic diagram of the various steps of the manufacturing method according to the present invention;

[0058] [ Figure 5 [Illustration 1] is an exploded view of an embodiment of an electronic system according to the present invention.

[0059] In the various figures, similar elements are indicated by the same reference numerals. Furthermore, the various elements are not necessarily shown to scale in order to present views that facilitate a better understanding of the invention. Specific Implementation

[0060] Figure 1 An embodiment of the electronic module 1 according to the present invention is illustrated schematically.

[0061] The electronic module 1 includes a power component, at least one signal board 11 and at least one conductive connection device 12, and a housing 13 encapsulated on the power component, the signal board 11 and the at least one connection device 12.

[0062] According to one embodiment, the encapsulation material of the housing 13 is epoxy resin.

[0063] The power assembly includes a power board 101, at least one conductive track 102 spaced apart from the power board 101, and at least one connection pad 103.

[0064] The set of conductive tracks 102 forms a connecting grid (or “lead frame”).

[0065] The power board 101 includes a substrate 1011, which forms a main support for the electronic module 1.

[0066] The power board 101 further includes at least one power portion 1012 deposited on the substrate 1011. The power portion 1012 is a flat strip that is directly disposed on the substrate 1011, parallel to each other and coplanar.

[0067] according to Figure 1 In the embodiment shown, the power board includes four power sections 1012, which are at potential B-, potential B+, or phase potential.

[0068] The power board also includes at least one power transistor. The power transistor allows direct current to be converted into a multiphase current system and vice versa. This can involve, for example, an insulated-gate field-effect transistor (IGFET) or a MOSFET (metal-oxide-semiconductor field-effect transistor).

[0069] Each power section 1012 is electrically connected to at least one conductive track 102 via at least one connection pad 103. Thus, each power section 1012 is electrically connected to the lead frame.

[0070] Connection pads 103 arranged between the power section 1012 and the lead frame are used to transfer power between the power section 1012 and the conductive trace 102.

[0071] exist Figure 1 In the image, pad 103 is presented in a cylindrical shape. This representation is by no means limiting. Pads can be presented in different shapes, such as cubes, parallelepipeds, or any other large-volume shape.

[0072] The signal board 11 is electrically connected to the power board 101. The signal board 11 is connected to various power transistors on the power board 101 to send signals for controlling the power transistors.

[0073] Connection devices 12 are electrically connected to signal board 11. These connection devices 12 allow electrical control signals to be transmitted between signal board 11 and the outside of electronic module 1.

[0074] Figure 2 An alternative embodiment of the electronic module 1 according to the present invention is shown.

[0075] In this embodiment, at least one conductive track 102 includes a first portion 1021 having a flat shape and a second portion 1022 having a three-dimensional shape. The second portion 1022 of the conductive track 102 includes a connecting pad 1023 forming the free end of the conductive track 102. The pad 1023 of the second portion 1022 of the conductive track 102 is flush with the outer surface of the housing 13.

[0076] Advantageously, the connection pad 1023 allows for a representative value of the voltage of the conductive trace 102 of the lead frame.

[0077] According to one embodiment, at least one connection pad 1023 is flat and parallel to the power board 101.

[0078] According to one embodiment, the second portion 1022 of the conductive track 102 includes a folded strip of conductive material.

[0079] Therefore, the longitudinal direction should be considered as the direction along the length of the substrate 1011 of the electronic module 1, and the transverse direction should be considered as the direction along the width of the substrate 1011.

[0080] According to one embodiment, the cross-sectional dimension of the first portion 1021 of the conductive track 102 is larger than a predetermined value, the predetermined dimension being designed to allow current flow, particularly such that the current density is less than 100 A rms / mm2.

[0081] According to one embodiment, the first portion 1021 may have a cross-section of 3.5 mm × 0.8 mm.

[0082] refer to Figure 3 The connecting device 12 includes a first surface 121 and a second surface 122 that are parallel to each other and connected to each other by an elastic deformation device 123.

[0083] The first surface 121 of the connecting device 12 is electrically connected to the signal board 11. This connection is made by a conductive means, such as soldering, laser or ultrasonic soldering, brazing, conductive bonding or any other equivalent means.

[0084] To facilitate connection to the signal board, at least one connection device 12 may include at least one notch 1211 on its first surface. The notch allows for visual confirmation of solder quality (AOI), and for this purpose, the base of the fixture is wider than the head (top surface) so that the notch is visible when viewed from above.

[0085] The second surface 122 of the connection device 12 is flush with the outer surface of the housing 13 of at least one connection device 12 of the packaged power component, signal board 11 and electronic module 1.

[0086] According to one embodiment, at least one elastic deformation device 123 of the connecting device 12 is arranged to ensure the parallelism of the first surface 121 and the second surface 122 during deformation of the device 123 in a direction perpendicular to the surfaces of the first surface 121 and the second surface 122.

[0087] According to one embodiment, at least one connecting device 12 includes a folded strip of conductive material. The folded strip can include at least one recess near at least one fold 1231.

[0088] Part 1232. Advantageously, the recess 1232 facilitates the folding of the strip.

[0089] According to one embodiment, the strip includes a plurality of folds 1231 and at least one recess 1232 near each fold 1231. Each recess 1232 may have the same shape, or at least two recesses 1232 may have different shapes.

[0090] According to one embodiment, at least one connecting device 12 includes a folded strip of conductive material, the strip including at least one reduced portion 1233 in the cross-section of the strip near at least one fold 1231. Advantageously, the reduced portion 1233 facilitates the folding of the strip.

[0091] Figure 1 An electronic module 1 comprising five connection devices 12 is shown. This example configuration is by no means limiting, and different numbers of connection devices 12 are possible.

[0092] According to one embodiment, the electronic module 1 includes at least two connection devices 12, wherein each connection device is aligned in a direction perpendicular to the edge of the signal board 11.

[0093] According to another embodiment, the electronic module 1 includes at least three connection devices 12, wherein the connection devices are aligned with each other.

[0094] The connecting device 12 can be S-shaped, such as Figure 3 As shown, or any other shape, such as Z-shaped, C-shaped, or Σ-shaped. Advantageously, these shapes allow the connecting device 12 to be flexible in a direction perpendicular to the surfaces of the first surface 121 and the second surface 122.

[0095] Another object of the present invention is a mold 2, which is configured to encapsulate the housing 13 on the power components, signal board 11 and at least one connection device 12 of the electronic module 1 as described above.

[0096] According to one embodiment, the mold 2 is configured to define at least one outer surface of the housing of the electronic module 1 and to engage with a second surface 122 of at least one connecting device 12.

[0097] According to one embodiment, the mold 2 includes at least one recess 21 configured to mate with a second surface 122 of at least one connecting device 12. The at least one recess 21 has a shape that matches the shape of the second surface 122 of the at least one connecting device 12.

[0098] According to one embodiment, the engagement of the recess 21 of the mold 2 with the second surface 122 of the connecting device 12 is achieved by compression in a direction perpendicular to the second surface 122.

[0099] Figure 4 Various steps of an embodiment of the method for manufacturing electronic module 1 according to the present invention are shown.

[0100] According to one embodiment, the method further includes the following steps:

[0101] - Provide at least one signal board 11;

[0102] - Provide at least one connecting device 12, which includes a first surface 121 and a second surface 122 that are parallel to each other and connected to each other by an elastic deformation device 123. The elastic deformation device 123 is arranged to ensure the parallelism of the first surface 121 and the second surface 122 during deformation of the device 123;

[0103] - Connect the first surface 121 of at least one connection device 12 to at least one signal board 11;

[0104] - Provide at least one mold 2;

[0105] - Apply the mold 2 to contact the second surface 122 of at least one connecting device 12;

[0106] - Using mold 2, at least one elastic deformation device 123 of connecting device 12 is deformed by compression.

[0107] According to one embodiment, the compressive force of each connecting device 12 ranges from approximately 100N to 200N.

[0108] During this step, a portion of the mold 2 presses against the second surface 122 of at least one connecting device, compressing the device 12 in a direction perpendicular to the surface of the second surface 122. This compression... Figure 4 The arrow indicates this.

[0109] Advantageously, the movement of the mold 2 on at least one connecting device 12 allows the second face 122 of the device 12 to be brought into position and its height set. This ensures that the second faces 122 of the various connecting devices 12 are aligned in height. Similarly, the flexibility of the connecting devices 12 prevents them from breaking during compression.

[0110] According to one embodiment, the first surface 121 and the second surface 122 are not parallel to each other and are formed at an angle between about 2° and 5° during the step of supplying at least one connecting device 12. Then, upon completion of the compression deformation step, the mold 2 positions the second surface 122 such that the first surface 121 and the second surface 122 are parallel to each other.

[0111] Another advantage of the interaction between the mold 2 and the second surface 122 of at least one positioning device 12 is ensuring good flatness of these second surfaces 122. This can be of interest, for example, when fastening tabs are electrically connected to these second surfaces 122. This ensures a good degree of vertical positioning tolerance because the dimensions are derived from the mold and the mold interacts with the clean second surface 122.

[0112] Resin (e.g., epoxy resin) is injected into mold 2 to encapsulate housing 13 onto at least one signal board 11 and at least one connection device 12.

[0113] When the resin is injected, at least one connecting device 12 is compressed in a direction perpendicular to a first surface 121 and a second surface 122 of the connecting device 12. After cooling and polymerization, the resin will set the position of at least one connecting device 12.

[0114] Advantageously, the movement of the mold 2 on the connecting device 12 restricts or even prevents resin from depositing onto the second surfaces 122 of these devices 12. Therefore, this limits the surface of these second surfaces 122 that must be reworked to remove the resin.

[0115] According to one embodiment, the manufacturing method includes the steps of supplying a power assembly comprising at least one power board 101 and electrically connecting a signal board 11 to the power board 101. In this embodiment, a housing 13 is allowed to encapsulate the power assembly, at least one signal board 11, and at least one connection device 12 within a resin injection mold 2.

[0116] According to one embodiment, the manufacturing method further includes a step of cleaning the second surface 122 of at least one connecting device 12. One purpose of this step is to remove any injection material that may have been deposited on the second surface of the connecting device 12 from the housing 13, thereby obtaining a clean contact surface, for example, suitable for allowing electrical contact with another element (e.g., a connecting tab).

[0117] According to one embodiment, the step of cleaning the second surface 122 of at least one connecting device 12 is performed by deburring or laser ablation.

[0118] According to one embodiment of the method, the mold 2 for injecting the housing 13 includes at least one recess 21. The recess 21 is configured to mate with a second surface 122 of at least one connecting device. For this purpose, the at least one recess 21 has a shape that matches the shape of the second surface 122 of the at least one connecting device 12.

[0119] When the injection housing 13 is completed, at least one recess 21 in the mold will create at least one boss 131 in the surface of the housing. The second surface 122 of the connecting device 12 opposite to the recess will be flush with the outer surface of the boss 131 of the housing 13.

[0120] refer to Figure 5 Another object of the present invention is an electronic system 3 comprising the electronic module 1 and interconnector 31 as described above.

[0121] Interconnector 31 is an overmolded component that allows various connecting pins 310 to be assembled on the same part.

[0122] According to one embodiment, the interconnect 31 includes a plurality of tabs 311, each of which is electrically connected to a first end of various pins 310. The tabs 311 of the interconnect are intended to be electrically connected to pads of the electronic module 1, such as the pad 1023 described above, and / or the second surface 122 of the connection device 12. The connection can be made by soldering, brazing, conductive bonding, or any other equivalent means.

[0123] According to one embodiment, the various tabs 311 of the interconnect 31 are arranged in one or more rows.

[0124] exist Figure 4In the example shown, the interconnect tabs 311 are arranged in two rows. The first row is arranged along the outer edge of the interconnect 31. The second row is arranged inside the interconnect 31. An opening 313 is made in the overmolding of the interconnect 31 to allow access to the second row of tabs 311, for example, to electrically connect the tabs 311 to their connection pads on the electronic module 1.

[0125] According to one embodiment, various pins 310 of the interconnect 31 are oriented perpendicular to the surface of the interconnect 31.

[0126] The second end 312 of the pin 310 of the interconnector 31 is intended to be electrically connected to at least one printed circuit board attached to the electronic module 1, for example, by insertion into a through hole of the printed circuit board, for example, by press fitting into a through hole of the printed circuit board.

[0127] According to one embodiment of the electronic system 3, the interconnector 31 is indexed relative to the electronic module 1. For this purpose, the electronic module 1 may include at least one first positioning member 1025 defining a reference position on the electronic module 1. The interconnector 31 includes at least one second positioning member 315 configured to cooperate with the at least one first positioning member 1025.

[0128] exist Figure 4 In the example shown, the first positioning member 1025 is manufactured on the conductive track 102 in the form of a concave member (i.e., a cylindrical hole). The second positioning member 315 is manufactured in the form of a convex member (i.e., a cylindrical pin) in the overmolding of the interconnect.

Claims

1. An electronic module (1), comprising: - A power component, the power component comprising: -Power board (101); and -At least one conductive track (102); - Signal board (11) mounted on the power board (101); - At least one conductive connection device (12), the connection device (12) comprising a first surface (121) and a second surface (122) parallel to each other and connected by an elastic deformation device (123), the first surface (121) being connected to the signal board (11); and - Housing (13) that encloses the power component, the signal board (11), and the at least one connection device (12), wherein: - The second surface (122) of the at least one connecting device (12) is flush with the outer surface of the housing; and - The at least one connecting device (12) is compressed in a direction perpendicular to the first surface (121) and the second surface (122) of the connecting device (12).

2. The electronic module (1) according to claim 1, wherein At least one elastic deformation device (123) of the connecting device (12) is arranged to ensure the parallelism of the first surface (121) and the second surface (122) during deformation of the device (123) in a direction perpendicular to the surface of the first surface (121) and the second surface (122).

3. The electronic module (1) according to claim 1 or 2, wherein The first surface (121) of at least one connecting device (12) includes at least one notch (1211) to facilitate connection of the at least one connecting device (12) to the signal board (11).

4. The electronic module (1) according to any one of the preceding claims, wherein At least one connecting device (12) includes a folded strip of conductive material, the strip including at least one recess (1232) near at least one fold (1231).

5. The electronic module (1) according to any one of the preceding claims, wherein, The first surface (121) of at least one connecting device (12) is connected to the signal board (11) by means of conductive bonding, soft soldering or hard soldering.

6. The electronic module (1) according to any one of the preceding claims, wherein The at least one conductive track (111) includes: - The first part (1111) presents a flat shape; and - A second portion (1112) presenting a three-dimensional shape, the second portion (1112) of the conductive track (111) including a connecting pad (1115) forming the free end of the track (111); and The connecting pad (1115) of the second part (1112) of the conductive track (111) is flush with the outer surface of the housing (13).

7. A mold (2) configured to encapsulate a housing (13) on the power components, signal board (11), and at least one connection device (12) of an electronic module (1) according to any one of the preceding claims. The at least one connecting device (12) includes a first surface (121) and a second surface (122) that are parallel to each other and connected to each other by an elastic deformation device (123). The mold (2) is configured to define at least one outer surface of the housing (13) and engage with the second surface (122) of at least one connecting device (12).

8. The mold (2) according to the preceding claim, wherein, The mold (2) includes at least one recess (21) configured to engage with the second surface (122) of at least one connecting device (12), the at least one recess (21) having a shape that matches the shape of the second surface (122) of at least one connecting device (12).

9. The mold (2) according to the preceding claim, wherein, At least one recess (21) engages with the second surface of at least one connecting device (12) by compression in a direction perpendicular to the second surface (122).

10. A method for manufacturing an electronic module (1) according to any one of claims 1 to 6, comprising the following steps: - Provide at least one signal board (11); - Provide at least one connecting device (12), the at least one connecting device (12) including a first surface (121) and a second surface (122) that are parallel to each other and connected to each other by an elastic deformation device (123), the elastic deformation device (123) being arranged to ensure the parallelism of the first surface (121) and the second surface (122) during deformation of the device (123); - Connect the first side (121) of at least one connection device (12) to at least one signal board (11); - Provide at least one mold (2) according to any one of claims 7 to 9; - Apply the mold (2) to contact the second surface (122) of the at least one connecting device (12); - Using the mold (2), the elastic deformation device (123) of the at least one connecting device (12) is deformed by compression; - Inject resin into the mold (2) to encapsulate the housing (13) onto the power component, the at least one signal board (11) and the at least one connection device (12).

11. The method of claim 10, further comprising the step of cleaning the second surface (122) of at least one connecting device (12).

12. An electronic system (3) comprising at least one electronic module (1) according to any one of claims 1 to 6 and an interconnect (31) comprising a plurality of tabs (311), each tab (311) being connected to a second side (122) of the connection device (12).

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