Electronic module, associated mold and method of manufacturing an associated electronic module.

Abstract

The invention relates to an electronic module (1) comprising:a connection track (11) having at least one opening (115),a sleeve (12) fixed in an electrically conductive manner to the connection track (11), said sleeve (12) comprising a first end having a foot (121) with a cross-section of a shape complementary to that of the opening (115) in the connection track (11), said foot (121) being housed in the opening (115) of the connection track (11).The invention also relates to an associated mold and a method for manufacturing an electronic module (1). Figure to be published with the abstract: Fig. 4

Description

Title of the invention: Electronic module, associated mold and method of manufacturing an associated electronic module. FIELD OF THE INVENTION

[0001] The present invention relates to the field of power electronics. The present invention relates more particularly to an electronic module.

[0002] The invention can find its application in electronic systems for inverters, for example, for traction, in on-board chargers, for electric cooling pumps, for example, for batteries, in heat pumps, in laser sensors, for example for autonomous driving, etc. STATE OF THE ART

[0003] It is known to use sleeves (or sleeves according to English terminology) in order to hold certain electrical pins of electronic modules. The electrical pins are inserted by force into the sleeves which thus make it possible to hold said pins by force above the electronic module.

[0004] By way of illustration, [Fig.l] represents an exemplary embodiment of a sleeve 12. In this example, the sleeve 12 is formed from a tube made of electrically conductive material such as copper, each end of which is turned over to form a collar. Each end of the sleeve 12 is open. These sleeves are intended to be soldered, for example on a connection track (or "leadframe" according to English terminology).

[0005] A problem arises when welding the sleeves. Indeed, during this operation the sleeves are likely to move, as illustrated in [Fig.2], causing a variation in their position and therefore in the position of the electrical pins.

[0006] One aim of the invention is in particular to correct all or part of the drawbacks of the prior art by proposing a solution making it possible to reduce the dispersions in the position of the sleeves during their welding.

[0007] BRIEF DESCRIPTION OF THE INVENTION

[0008] For this purpose, the invention relates to an electronic module comprising: a connection track having at least one opening, a sleeve fixed in an electrically conductive manner to the connection track, said sleeve comprising a first end having a foot with a cross-section of a shape complementary to that of the opening in the connection track, said foot being housed in the opening of the connection track.

[0009] According to one embodiment, the sleeve is fixed by at least one means taken from electrically conductive bonding, welding or brazing.

[0010] According to one embodiment, the sleeve comprises a second end, said second end being deformable by compression.

[0011] According to one embodiment, the sleeve is fixed to the connection track at the foot of said sleeve.

[0012] According to one embodiment, the sleeve comprises a fixing zone, for example, a collar or several tabs, the sleeve being fixed to the connection track by the fixing zone.

[0013] According to one embodiment, the sleeve comprises a second end, said second end of the sleeve having a flared shape.

[0014] According to one embodiment, the second end of the sleeve has a hemispherical shape.

[0015] The invention also relates to a mold configured to cooperate with at least one sleeve of an electronic module as described previously, said mold comprising at least one protrusion of a shape complementary to the shape of a second end of the sleeve.

[0016] According to one embodiment, the at least one protrusion has a hemispherical shape, the diameter of the hemisphere of the protrusion being greater than that of the hemisphere of the sleeve. Alternatively, the diameter of the hemisphere of the protrusion is less than that of the hemisphere of the sleeve.

[0017] According to one embodiment, the mold comprises at least one through nozzle, said nozzle opening at the level of the at least one protrusion.

[0018] A third object of the invention is a method of manufacturing an electronic module comprising the following steps: - provide at least one connection track; - form an opening in the connection track; - providing at least one sleeve having a first end comprising a foot having a section of shape complementary to that of the opening in the connection track; - place the foot of the sleeve in the opening of the connection track; - fixing the sleeve to the connection track by an electrically conductive means;

[0019] According to one embodiment of the method, the at least one sleeve comprises a second end deformable by compression, and the method further comprises the following steps: - provide at least one mold comprising at least one protrusion of a shape complementary to the shape of the second end of the sleeve; - apply the mold, in contact with the sleeve; - deform, by compression, the second end of the sleeve using at least one protrusion of the mold.

[0020] According to one embodiment, the method further comprises the following step: - depositing a film, for example a fluoropolymer film, between the second end of the sleeve and at least one protrusion of the mold.

[0021] According to one embodiment of the method, the fixing step is carried out at the foot of the sleeve.

[0022] According to one embodiment of the method, the fixing step is carried out at the fixing zone of the sleeve.

[0023] According to one embodiment of the method, the fixing step is carried out by a means taken from among brazing, welding or electrically conductive bonding. BRIEF DESCRIPTION OF THE FIGURES

[0024] Other features and advantages of the present invention will appear more clearly on reading the description below, given for illustrative and non-limiting purposes, and with reference to the appended figures, in which:

[0025] [Fig. 1], previously described, represents an exemplary embodiment of a sleeve known from the prior art;

[0026] [Fig.2], previously described, illustrates the dispersion of the sleeves during their fixing;

[0027] [Fig.3] is a schematic representation of a detail, centered around a sleeve, of an embodiment of an electronic module before its overmolding;

[0028] [Fig.4] represents a detail of an electronic module, according to the invention, after its overmolding;

[0029] [Fig.5] is a detail, centered around a particular embodiment of a sleeve, of an alternative embodiment of an electronic module, before its overmolding;

[0030] [Fig.6] illustrates the cooperation between one end of a sleeve and the protrusion of a mold as a function of the height of said sleeve;

[0031] [Fig.7] illustrates a problem related to the height dispersion of sleeves.

[0032] In the various figures, similar elements are designated by identical references. Furthermore, the various elements are not necessarily represented to scale in order to present a view making it easier to understand the invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] Subsequently, the term “height of the sleeve” will refer to the longitudinal distance of said sleeve. The same will apply to the “height of the foot of a sleeve” which will refer to the longitudinal distance of the foot of the sleeve. The “connection track height” will refer to the distance along an axis perpendicular to the surface of the connection track.

[0034] [Fig. 3] shows a detail, centered around a sleeve 12, of an embodiment of an electronic module 1 according to the invention before its overmolding.

[0035] According to one embodiment, the electronic module 1 comprises a power module or an excitation module.

[0036] The electronic module 1 comprises at least one connection track 11 and at least one sleeve 12 fixed in an electrically conductive manner to the connection track 11.

[0037] The connection track 11 may extend, for example, over an insulator 30.

[0038] The sleeve 12 can be fixed to the connection track by gluing using an electrically conductive glue. According to another embodiment, the sleeve 12 is welded or brazed onto the connection track 11.

[0039] According to one embodiment, the sleeve 12 comprises a foot 121 closing a first end of the sleeve 12.

[0040] According to one embodiment, the connection track 11 comprises at least one opening 115 at the location of a sleeve 12. This opening 115 is intended to receive the foot 121 of a sleeve 12. The foot 121 of the sleeve 12 has a cross-section of shape complementary to that of the opening 115 in the connection track 11.

[0041] The opening 115 of the connection track 11 is, for example, a blind or through hole of cylindrical shape. In this exemplary embodiment, the section of the foot 121 of the sleeve 12 is round.

[0042] Preferably, the foot 121 extends over the entire height of the connection track, thus ensuring good retention of the sleeve 12 in the connection track 11.

[0043] Thus, by housing the foot 121 of the sleeve 12 in the opening 115, the sleeve is directly anchored and referenced on the connection track 11. In addition, housing the foot 121 of the sleeve in the connection track 11 makes it possible to hold the sleeve 12 during its fixing. This therefore reduces the risk of the sleeve moving during this operation.

[0044] According to one embodiment, the sleeve 12 is fixed to the connection track at its foot 121.

[0045] According to an alternative embodiment, the sleeve 12 may comprise a fixing zone 125. This fixing zone 125 is intended to fix the sleeve to the connection track.

[0046] In the example of [Fig. 3], the fixing zone 125 is a collar extending over the entire circumference of the sleeve 12. This collar is fixed using a fixing joint 35, for example a solder joint, between the circumference of the collar and the connection track 11.

[0047] . According to another embodiment, the fixing zone 125 can take the form of at least one fixing lug located on the periphery of the sleeve 12. The fixing zone 125 can be formed by two diametrically opposite fixing lugs.

[0048] The sleeve 12 is intended to receive an electrical connection pin (not shown). The electrical connection pin is forcibly inserted by the end opposite the first end having the foot 121 of the sleeve 12. After its insertion into the sleeve 12, the electrical connection pin is in electrical contact with the sleeve 12 which itself is in electrical contact with the connection track 11.

[0049] Advantageously, the presence of a foot 121 closing the end of the sleeve 12, intended to be fixed to the connection track 11, makes it possible to prevent any entry of solder inside the sleeve. Indeed, during the step of soldering the sleeve 12, a solder joint is deposited on the outer circumference of the collar. There is therefore a risk that solder will penetrate inside the end of the sleeve and thus obstruct it, thus preventing the insertion of an electrical connection pin.

[0050] With reference to [Fig.4], after the assembly of the elements of the electronic module 1, a mold 2 is applied to the assembly. Epoxy resin 40 is then injected in order to overmold the electronic module 1. The mold 2 is configured to cooperate with at least one sleeve 12 of the electronic module 1 and more particularly a second end 122 of said at least one sleeve 12.

[0051] [Fig. 5] shows, before its overmolding, a detail, centered around a sleeve 12, of an alternative embodiment of an electronic module 1 according to the invention. In this example, the sleeve 12 is fixed on a connection track 11 molded by transfer (or TML for “Transfer Molded Leadframe” according to English terminology).

[0052] In this embodiment, the sleeve 12 is fixed between two electrically conductive plates and at the same electrical potential of the connection track 11. These may be, for example, two copper plates. These two electrically conductive plates are in contact with a heat sink 50 via a layer 51 of thermal grease or thermal glue.

[0053] The sleeve 12 is, for example, fixed to the connection track 11 by means of a fixing joint 35, such as an electrically conductive glue joint, between two diametrically opposite fixing lugs and the connection track 11.

[0054] In this embodiment, the foot of the sleeve 12 has a height less than the height of the connection track 11.

[0055] [Fig. 5] also represents a particular embodiment of a sleeve 12 according to the invention. In this example, the inner part of the second end 122 of the sleeve 12, that is to say the end opposite the first end having a foot 121, has a flared shape.

[0056] According to a particular embodiment, the inner part of the second end 122 of the sleeve 12 is of hemispherical shape.

[0057] According to an alternative embodiment, the second end 122 of the sleeve 12 is deformable by compression.

[0058] With reference to [Fig.6], the invention also relates to a mold 2 configured to cooperate with at least one sleeve 12 of the electronic module 1 and more particularly with the interior of its second end 122.

[0059] In the embodiment illustrated in this figure, the mold 2 comprises at least one protrusion 21. This protrusion 21 has a shape complementary to the shape of the inner part of the second end of the at least one sleeve 12 with which the protrusion 21 will cooperate.

[0060] According to one embodiment, the mold 2 has at least one protrusion 21 of hemispherical shape. Similarly, the inner part of the second end 122 of the sleeve 12 with which the protrusion 21 will cooperate has a flared hemispherical shape. According to a feature of the invention, the diameter of the hemisphere of the protrusion 21 is greater than that of the hemisphere of the inner part of the second end 122 of the sleeve 12 with which the protrusion 21 will cooperate.

[0061] According to one embodiment, the mold comprises at least one nozzle 22 passing through and opening at the level of at least one protrusion 21 of the mold 2.

[0062] Advantageously, the flared shape and the deformable nature of the second end 122 of the sleeve 12 in cooperation with a protrusion 21 of complementary shape of the mold 2 make it possible to compensate for the dispersions in height of the sleeves 12. This will be better understood with reference to Figures 6 and 7. These figures represent a detail of an electronic module 1, at the end of its overmolding, centered around sleeves 12a, 12b, 12c, 12d of different heights.

[0063] In the example of [Fig.7], a sleeve 12c has a height lower than that of the other sleeves 12d. When a mold 2 is applied in contact with the second end 122d of the sleeves 12d, the second end 122c of the sleeve 12c is not in contact with the mold 2. There is therefore a free space between said second end 122c, which is open, and the mold 2. Thus, during the overmolding step, for example by injection of epoxy resin, resin is likely to penetrate inside the sleeve 12c and therefore obstruct it. Subsequently, the introduction of an electrical connection pin will be made impossible.

[0064] [Fig. 6] illustrates the cooperation between the inner part of the second end 122b, 122c, 122d of a sleeve 12b, 12c, 12d and the protrusion of a mold 2 as a function of the height of said sleeve. In this example, the inner part of the second ends 122a, 122b, 122c, 122d of the sleeves 12a, 12b, 12c, 12d have a hemispherical shape and are deformable by compression. The protrusions 21 of mold 2 also have a hemispherical shape.

[0065] The second end 122a of the sleeve 12a is not in contact with the mold 2. This sleeve makes it possible to visualize the shape of the second end 122a before compression.

[0066] It is considered that the sleeve 12d has the correct height. Its second end 122d cooperates perfectly with the protrusion 21 of the mold 2. The mold 2 therefore correctly obstructs the second end 122d of the sleeve 12d, thus preventing any resin from penetrating inside the sleeve 12d during the resin injection step.

[0067] The sleeve 12c has a height lower than the normal value. When the protrusion 21 of the mold 2 comes into contact with the second end 122c of this sleeve 12c, these two elements do not cooperate perfectly. However, the protrusion 21 of the mold 2 slightly compresses the second end 122c of the sleeve 12c, thus ensuring the closure of the second end 122c. This thus prevents any intrusion of resin into the sleeve 12c during the overmolding step.

[0068] The sleeve 12b has a height greater than the normal value. When the protrusion 21 of the mold 2 comes into contact with the second end 122c of this sleeve 12c, these two elements cooperate in an extreme manner. The protrusion 21 of the mold 2 completely compresses the second end 122c of the sleeve 12c. The flexibility of the second end 122b makes it possible not to block the mold 2 and allows it to position itself correctly relative to the other sleeves. This flexibility also allows the protrusion 21 of the mold 2 to close the second end 122b. Thus, even if the sleeve has a height greater than normal, the intrusion of resin into this sleeve 12b is avoided.

[0069] The invention also relates to a method for manufacturing an electronic module 1 as described previously. The method comprises the following steps: - provide at least one connection track 11; - form an opening 115 in the connection track 11; - providing at least one sleeve 12 having a first end comprising a foot 121, said foot having a section of shape complementary to that of the section of the opening 115 in the connection track 11; - house the foot 121 of the sleeve 12 in the opening 115 of the connection track 11; - fix the sleeve 12 to the connection track 11 by an electrically conductive means.

[0070] According to one embodiment of the method, the opening 115 may be a circular hole. In this case, the section of the foot 121 of the sleeve 12 is also circular.

[0071] The opening 115 can be made by a chemical etching process of the connection track 11.

[0072] According to one embodiment, the step of fixing the foot 121 in the connection track 11 can be carried out by electrically conductive gluing, by welding or by brazing.

[0073] According to one embodiment, the step of fixing the foot 121 in the connection track 11 is carried out at the level of the foot 121 of the sleeve 12.

[0074] According to an alternative implementation, the step of fixing the foot 121 in the connection track 11 is carried out at the level of the fixing zone 125 of the sleeve 12.

[0075] According to one embodiment of the method, during the step of providing at least one sleeve 12, said at least one sleeve 12 comprises a second end 122 deformable by compression. The method further comprises the following steps: - provide at least one mold 2 comprising at least one protrusion 21 of a shape complementary to the shape of the second end 122 of the at least one sleeve 12; - apply the mold 2, in contact with the second end 122 of the at least one sleeve 12; - deform, by compression, the second end 122 of the at least one sleeve 12 using the at least one protrusion 21 of the mold 2.

[0076] According to one embodiment, the method further comprises a step of depositing a film between the second end 122 of the at least one sleeve 12 and the at least one protrusion 21 of the mold 2.

[0077] According to one embodiment, the film is a fluoropolymer film.

[0078] According to one embodiment, the method comprises an overmolding step during which resin, for example epoxy, is injected onto the various elements of the electronic module 1, after the application of the mold 2 in contact with the second end 122 of the at least one sleeve 12.

[0079] According to one embodiment, the method comprises a step of polymerization of the overmolding resin.

[0080] The invention has been described above with the help of embodiments presented in the figures, without limitation of the general inventive concept.

[0081] Many other modifications and variations suggest themselves to those skilled in the art, after reflection on the different embodiments illustrated in this application.

[0082] These embodiments are given by way of example and are not intended to limit the scope of the invention, which is determined exclusively by the claims below.

[0083] In the claims, the word "comprising" does not exclude other elements or steps.

[0084] The mere fact that different features are recited in mutually dependent claims does not indicate that a combination of these features cannot be advantageously used. Finally, any reference used in the claims should not be interpreted as a limitation of the scope of the invention.

Claims

Claims

1. Electronic module (1) comprising: a connection track (11) having at least one opening (115), a sleeve (12) fixed in an electrically conductive manner to the connection track (11), said sleeve (12) comprising a first end having a foot (121) of section of shape complementary to that of the opening () in the connection track (11), said foot (121) being housed in the opening () of the connection track (11).

2. Electronic module (1) according to the preceding claim, wherein said sleeve (12) comprises a second end (122), said second end (122) being deformable by compression.

3. Electronic module (1) according to one of claims 1 or 2, wherein the sleeve (12) is fixed to the connection track (11) at the foot (121) of said sleeve (12).

4. Electronic module (1) according to one of the preceding claims, wherein the sleeve (12) comprises a fixing zone (125), for example, a collar or several tabs, the sleeve (12) being fixed to the connection track (11) by the fixing zone (125).

5. Electronic module (1) according to one of the preceding claims, wherein said sleeve (12) comprises a second end (122), said second end (122) of the sleeve (12) having a flared shape.

6. Mold (2) configured to cooperate with at least one sleeve (12) of an electronic module (1) according to one of the preceding claims, said mold (2) being characterized in that it comprises at least one protrusion (21) of a shape complementary to the shape of a second end (122) of the sleeve (12).

7. Mold (2) according to the preceding claim comprising at least one through nozzle (22), said nozzle (22) opening at the level of the at least one protrusion (21).

8. Method for manufacturing an electronic module (1) comprising the following steps: - providing at least one connection track (11); - forming an opening (115) in the connection track (11); - providing at least one sleeve (12) having a first end comprising a foot (121) having a cross-section of shape complementary to that of the opening (115) in the connection track (11); - housing the foot (121) of the sleeve (12) in the opening (115) of the connection track (11); - fixing the sleeve (12) to the connection track (11) by an electrically conductive means;

9. Method according to the preceding claim, wherein the at least one sleeve (12) comprises a second end (122), said second end (122) being deformable by compression, and the method further comprising the following steps: - providing at least one mold (2) comprising at least one protrusion (21) of a shape complementary to the shape of the second end (122) of the sleeve (12); - applying the mold (2), in contact with the sleeve (12); - deforming, by compression, the second end (122) of the sleeve (12) using the at least one protrusion (21) of the mold (2).

10. Method according to the preceding claim further comprising the following step: depositing a film (), for example a fluoropolymer film, between the second end (122) of the sleeve (12) and the at least one protrusion (21) of the mold (2).

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