Cooling insert for a power module and its manufacturing process

Abstract

Cooling Insert for a Power Module and its Manufacturing Method. The invention relates to a cooling insert (30) intended to be interposed between a first wall and a heat source, the insert (30) extending between an upper surface (31) and a lower surface (32) and comprising, in a cross-sectional plane (P1) of the insert perpendicular to an elongation axis (X1), a plurality of adjacent motifs (33) in the cross-sectional plane (P1) forming first orifices (36), each motif (33) extending between a first end (34) flush with the upper surface (31) and a second end (35) flush with the lower surface (32), each motif (33) having its first end (34) with a width (d1) greater than that (d2) of its second end (35). The invention also covers a cooling device comprising such an insert, as well as a method for manufacturing the insert and the cooling device. (Figure 2)

Description

Title of the invention: Cooling insert for a power module and its manufacturing method

[0001] The present invention relates to the field of on-board chargers for electric cars and more specifically to a cooling insert for a power module.

[0002] On-board chargers include various electronic components such as power modules, coils, or capacitors, without this list being exhaustive. These electronic components generate heat during the operation of the on-board charger.

[0003] However, electric vehicles require ever-increasing charging power to reduce charging times. This increase in charging power is accompanied by a growing heat generation during charger operation, necessitating the development of solutions to reduce thermal stress on charger components.

[0004] In particular, power modules are the electronic components that produce the most heat and it is necessary to cool them efficiently so as not to damage them, while power modules can have an operating temperature of 150°C.

[0005] The power module is increasingly used in electronic systems because it allows a plurality of electronic chips to be packed into a small space on a printed circuit board. More specifically, the power module comprises a housing in which electronic chips are arranged side by side. The housing includes a base for supporting the electronic chips and a cover plate that encloses the chips and, together with the base, forms an internal volume in which the chips are housed. The chips are connected to electrical connection pins that extend outside the power module, notably to allow the electrical connection of the electronic chips, housed inside the casing, to an electrical network via a printed circuit board.

[0006] The power module typically has a rectangular shape, defined by the rectangular shape of the housing. In other words, the power module comprises two opposing edges, each with a greater elongation dimension than the other two edges. The pins protrude from the housing on one or both edges with the greater elongation dimension.

[0007] It is known to cool a power module by placing this power module in contact with a wall of a cooling circuit in which a coolant circulates.

[0008] More specifically, an on-board charging device includes a cooling device formed by a receptacle and a closing wall that define a coolant circuit. This circuit is supplied by a coolant that recovers, through the closing wall, the heat generated during the operation of the power module attached to the closing wall. The shape of the coolant circuit is defined by a circulation channel formed by reliefs in the receptacle, this shape being designed to allow the coolant to pass under each of the power modules. It is known to place the power modules along the circulation channel, with these power modules arranged parallel to the direction of liquid flow in the area where the power module in question is attached.It is also known to place fins protruding from the sealing wall into the circulation channel in order to increase the heat exchange surface between the coolant and the sealing wall.

[0009] This cooling solution, although already very effective, can be improved by adapting the shape and dimensions of the fins. Unfortunately, the cold forging technology used to produce this type of finned insert does not offer flexibility in manufacturing the fins in terms of dimensions and fin pattern density.

[0010] The present invention falls within this context and aims to provide a cooling insert with a particular pattern that offers a large heat exchange surface with the coolant and a shape that allows it to conform to the contours of the circulation channel. In addition to being easy and inexpensive to produce, this new cooling insert guarantees better thermal performance than prior art solutions.

[0011] For this purpose, the invention relates to a cooling insert intended to be interposed between a first wall and a heat source, the insert extending between a top surface and a bottom surface and comprising, in a cutting plane of the insert perpendicular to the top surface, a plurality of adjacent motifs in the cutting plane forming first orifices, each motif extending between a first end flush with the top surface and a second end flush with the bottom surface, each motif having its first end of a width greater than that of its second end.

[0012] Thanks to these characteristics, the cooling insert extends between the receptacle and the closing wall, along the entire section of the coolant circuit. The orifices form the channels for the coolant to flow through the insert at various heights. The narrowing of the pattern widths corresponds to the narrowing of the channel walls within the insert. This configuration allows the insert to deform when placed in the cooling circuit channel, if necessary, thus eliminating the need for clearance between the insert's bottom surface and the base wall. These features ensure improved thermal performance of the insert within its cooling system.

[0013] According to one feature of the invention, each motif comprises a trunk extending from the first end of the motif to an intermediate zone, and at least two branches, each branch extending from a first end connected to the intermediate zone to a second end forming the second end of the motif, the two branches of a motif being intertwined.

[0014] These repeated patterns in a plane of the insert form the walls of a three-dimensional cooling insert structure with initial passage channels for the coolant. The passage channels extend parallel to the streamlines of the coolant flow. Contact of the coolant flowing through the passage channels allows the coolant to absorb heat transferred from the hot source (the power module) through the walls of the cooling insert.

[0015] Advantageously, the second ends of the two branches of a motif are joined together and form a first surface of the second end of the motif. The first surface of the second end constitutes a contact surface of the insert against the bottom wall.

[0016] Advantageously, the second ends of the two branches of a motif also form a second surface at the second end of the motif. This second surface at the second end also constitutes a contact surface of the insert against the bottom wall. The presence of two surfaces at the second end of a motif improves the insert's stability during its extrusion manufacturing.

[0017] In one embodiment of the invention, a pair of two adjacent motifs form second orifices.

[0018] The pairs of motifs, repeated in a plane of the insert, form the walls of the three-dimensional structure of the cooling insert with secondary passage channels for the coolant. Just like the first passage channels, the second passage channels extend parallel to the streamlines of the coolant flow. The contact surface of the coolant flowing through the passage channels is thus increased, which allows the coolant to absorb more of the heat passing through it. from the hot source (the power module) through the walls of the cooling insert.

[0019] Advantageously, a branch of a motif is connected to a branch of an adjacent motif. This connection between branches of two adjacent motifs, or contact by portions of neighboring branches, allows the passage channels for the coolant to be formed. When projected onto the cutting plane of the insert, the insert forms a grid through which the coolant flows. The insert is entirely immersed in the coolant.

[0020] Advantageously, a pair of two adjacent motifs forms a third orifice located between the two stems of the pair of adjacent motifs. These third orifices thus form third passage channels. Since the stems are preferentially located directly above the electronic chips, they absorb the most heat from the power module. The third passage channels are positioned as close as possible to the hot portions of the insert and the closing wall. This results in maximized cooling.

[0021] The invention also relates to a cooling device for a power module, the cooling device comprising a receptacle which includes at least one channel for the circulation of a coolant and a closing wall configured to rest against the receptacle to form with said channel a coolant circuit, said power module being made integral with the closing wall, the cooling device comprising at least one cooling insert as described above, the power module being the heat source and the first wall being a bottom wall of the channel, the cooling insert being disposed in the channel between the closing wall and the bottom wall of the channel.

[0022] Such a cooling device offers excellent thermal performance by ensuring proper cooling of the power module.

[0023] The invention also covers an on-board charging device comprising at least one housing, electronic components housed in said housing and among which at least one power module, the housing further housing a cooling device as described above.

[0024] The invention also covers a method for manufacturing such a cooling insert comprising the following steps: - supply of a thermally conductive compressed material, - passage through a die having a cross-section of shape complementary to the cross-section of the cooling insert in the cutting plane of the cooling insert.

[0025] The invention finally covers a method for manufacturing a cooling device as described above, the method comprising the following steps: - supply of a cooling insert as described above, and supply of the closing wall, - establishment of a metallic bond between the upper surface of the insert and an internal surface of the closing wall, - joining the closing wall and the receptacle.

[0026] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given by reference to the accompanying schematic drawings on the other hand, in which:

[0027] Figure [1] schematically represents a cooling device for a power module according to the invention,

[0028] Figure 2 schematically represents an embodiment of a cooling insert according to the invention,

[0029] Figure 3 schematically represents a cross-sectional view of the cooling insert according to the invention disposed in the coolant circulation channel,

[0030] Figure 4 schematically represents a cross-sectional view of another embodiment of the cooling insert according to the invention,

[0031] [Fig.5] schematically represents the steps of a manufacturing process for a cooling device according to the invention.

[0032] The features, variants, and different embodiments of the invention, as described or as they will be presented in the detailed description that follows, can be combined in various ways, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0033] For the sake of clarity, the same elements are designated by the same references in the different figures.

[0034] Figure 1 schematically represents a cooling device 50 for a power module 20 according to the invention. The cooling device 50 comprises a receptacle 6 which includes at least one channel 7 for the circulation of a coolant. The cooling device 50 includes a closing wall 8 (not shown) configured to rest against the receptacle 6. to form with said channel a cooling liquid circuit 10. The closing wall 8 can come into contact with the upper portions of the walls 11, 12 of the channel 7.

[0035] In this figure, the power module 20 is not shown. It can be seen in [Fig. 3]. The power module 20 has a rectangular shape, with a housing 22 containing electronic chips 62 and from which electrical connection pins (not shown) extend to allow the electrical connection of the electronic chips 62 to an electronic component such as a printed circuit board, also not shown here. A first wall of the housing is designed to be pressed against the closing wall 8.

[0036] A transverse axis X2 of the power module 20, allowing the orientation of the latter to be defined in relation to the cooling device 50 and the insert 30, is defined as being an axis perpendicular to the two large edges of the power module.

[0037] The power module 20 thus comprises a housing 22 covering electronic chips 62 arranged on a support from which extend the aforementioned electrical connection pins. The electronic chips 62 are arranged on the support in such a way that they can contribute to defining an orientation of the power module. Advantageously, the electronic chips 62 are arranged along an alignment axis that is parallel to the transverse axis X2 of the aforementioned power module 20. The orientation of the power module 20, transverse and perpendicular as appropriate, with respect to the direction of flow of the coolant, can thus be defined by the alignment of the electronic chips. In the example illustrated in [Fig. 3], the electronic chips 62 are said to be aligned along an alignment axis and form a straight row parallel to this alignment axis.

[0038] The coolant circulating in the cooling device is thus able to flow directly over the electronic chips, passing substantially simultaneously over each of these chips. The coolant therefore has a similar temperature at the point of contact with each of the electronic chips 62 of the power module 20, and the cooling of these chips via heat exchange through the insert is homogeneous. Consequently, the chips 62 do not exhibit any temperature differences, and the thermal management of the power module is simplified.

[0039] The cross-sectional view of [Fig. 3], taken in a cutting plane perpendicular to the direction of flow of the coolant, makes visible this alignment of the electronic chips parallel to the transverse axis X2. Furthermore, this [Fig. 3] makes particularly visible the feature of the invention according to which the insert 30 is interposed between the closing wall 8 and a bottom wall 9 of the receptacle 6.

[0040] The power module 20 is secured to the closing wall 8 in a positioning zone ZI of the power module.

[0041] According to the invention, the cooling device 50 comprises at least one cooling insert 30 disposed in the channel 7 between the closing wall 8 and the bottom wall 9 of the channel. The specific characteristics of the cooling insert are detailed below.

[0042] Figure 2 schematically represents one embodiment of an insert ofCooling insert 30 according to the invention. The cooling insert 30 of the invention is intended to be interposed between a first wall 9, corresponding to the bottom wall of the channel 7, and a heat source (the power module 20, via the closing wall 8). The cooling insert 30 extends vertically between an upper surface 31 and a lower surface 32, and between an inlet surface and an outlet surface along an elongation axis XL. In the embodiment shown in [Fig. 2], the cooling insert has a general rectangular parallelepiped shape. Along the elongation axis XI, the cooling insert extends between plane PI and plane P2. In other words, and as will become apparent from the subsequent description of the cooling insert, PI constitutes an inlet plane for the coolant into the insert, and P2 constitutes an outlet plane for the coolant from the insert.The general shape of the insert corresponds to the shape of the channel 7 between the bottom wall 9 and the closing wall 8.

[0043] The cooling insert 30 comprises, in a cross-sectional plane PI of the insert perpendicular to the elongation axis XI (and perpendicular to the upper surface 31), a plurality of adjacent motifs 33 in the cross-sectional plane PI, forming first orifices 36. In projection onto the plane PI, each motif 33 extends between a first end 34 flush with the upper surface 31 and a second end 35 flush with the lower surface 32. The first end 34 being flush with the upper surface 31 means that the first end 34 of the motif 33 terminates at the level of the upper surface 31. The first end 34 of the motif 33 is contained within the plane of the upper surface 31. The same is true for the second end 35, which is flush with the lower surface 32. The second end 35 of the motif 33 is contained within the lower surface 32.

[0044] The sequence of motifs 33 in plane PI corresponds to a section of the cooling insert. The motifs 33 extend along the elongation axis XL. The cooling insert 30 is therefore composed of a plurality of motifs 33 that extend from plane PI to plane P2 along the axis XL. The first orifices 36 thus form passage channels for the coolant through the insert 30. The passage channels extend from the inlet surface of the insert to its outlet surface and have the first orifice as their cross-section.

[0045] As can be seen in [Fig. 2], a single motif 33 can comprise several, for example three, first orifices. The first orifices of a single motif 33 are advantageously of different cross-section. Preferably, the cross-section of the first orifices increases when moving from the upper surface 31 to the lower surface 32.

[0046] Indeed, an essential feature of the invention is that, in projection in the plane PI, each motif 33 has its first end 34 of width dl greater than a width d2 of its second end 35. The motifs 33 extending between the upper surface 31 and the lower surface 32 form a three-dimensional structure comprising coolant passage channels each extending along an axis parallel to the axis XL. The passage channels are thus delimited by walls which taper towards the lower surface 32.

[0047] Advantageously, the insert can be made of a material such as copper or an aluminum alloy, the closing wall is made of an aluminum alloy having a different thermal conductivity, for example less than that of the material chosen to make the insert.

[0048] Thanks to these characteristics, the cooling insert, which is placed in the coolant circuit 10 between the receptacle and the closing wall, under the power module, completely occupies the cross-section of the coolant circuit. The insert is thus as close as possible to the heat source (the power module) and the cold source (the coolant). This results in improved heat exchange between the hot source and the coolant.

[0049] Furthermore, the thin walls of the three-dimensional structure of the cooling insert eliminate the need for any gap between the lower surface of the insert and the bottom wall. Indeed, the thinness of the walls of the three-dimensional structure allows for slight deformation of these walls. As a result, the insert occupies the entire cross-section of the cooling circuit, thus maximizing the flow of coolant through the insert's channels.

[0050] It is therefore understood that the combination of the plurality of flow channels extending parallel to the streamlines of the coolant and the decreasing width of the channel walls from the upper to the lower surface of the insert have a synergistic effect of maximizing the use of the coolant flow rate in the cooling circuit. This results in maximized cooling of the power module compared to existing solutions.

[0051] As shown on the right of [Fig. 2], in cross-section in plane PI, each motif 33 comprises a trunk 40 extending from the first end 34 of the motif 33 to an intermediate zone 41, and two branches 42, 43. Each branch extends from a first branch end 421 connected to the intermediate zone 41 to a second end 422 forming the second end 35 of the pattern 33, the two branches 42, 43 of a pattern 33 being intertwined to form the first orifices. By intertwining the two branches 42, 43, it should be understood that each branch extends from the intermediate zone 41 to the lower surface 32 of the insert in a wavy, or substantially sinusoidal, profile, and the branches 42, 43 intersect. As a result of this intertwining, the first orifices 36 are formed. In the illustration, there are three of them. Considered in its general form, it is the walls of the three-dimensional structure of the cooling insert that intertwine to form the first passage channels for the coolant.

[0052] Put another way, the interlacing of branches 42, 43 can also be defined by the fact that the branches with the undulating profile are in contact with each other, in portions, to form the first openings. Considered along the elongation axis XI, two branches of a motif form the walls that enclose the passage channels by bringing one wall into contact with the other around a channel.

[0053] This interlocking structure of the insert walls allows for the formation of a plurality of initial channels for the flow of coolant. The wall thickness decreases from the upper surface of the insert to its lower surface. This reduction in thickness allows, on the one hand, for more coolant to circulate through the insert, since the thinner wall thickness of the flow channels results in larger cross-sectional areas for the initial channels and therefore a larger heat exchange surface. On the other hand, it provides flexibility to the lower part of the insert. This flexibility allows the insert, in contact with the bottom wall 9, to deform and adapt to the available space in the coolant circuit.This deformation capacity of the insert removes manufacturing constraints from the insert since it is no longer necessary to provide a gap between the insert and the back wall, and good contact of the insert against the back wall is ensured.

[0054] According to an optional feature of the invention, the second ends 422, 432 of the two branches of a motif 33 are joined together and form a first surface 351 of the second end 35 of the motif. In other words, the two branches 42, 43 can meet at a surface 351. The surface 351 then has the same shape as the bottom wall 9. In an example of a flat bottom wall 9, the surface 351 is flat. The coolant passage channel located closest to the lower surface of the insert therefore has a flat lower wall.

[0055] According to an optional feature of the invention, the second ends 422, 432 of the two branches of a motif 33 further form a second surface 352 of the second end 35 of the motif. In other words, the two branches 42, 43 can to meet at a surface 351 and a surface 352. This embodiment is shown in [Fig. 2]. The insert therefore presents, for each motif 33, at its lower surface 32, a double surface contact between the bottom wall 9 and the insert. This feature provides better retention of the insert during its extrusion manufacturing.

[0056] In another embodiment of the invention, projected onto the PI plane, a pair 330 of two adjacent motifs 33 form second orifices 336. A branch of one motif is connected to a branch of an adjacent motif so as to form the second orifices. The second orifices are obtained by bringing the first branch of one motif into contact with the second branch of the adjacent motif. Considered in its general form, it is the walls of the three-dimensional structure of the cooling insert between two neighboring motifs that are partially in contact to form the second passage channels for the coolant.

[0057] Thanks to this double interlacing feature, i.e., by connecting sections between the two branches of the same motif and the two branches of two adjacent motifs, the insert includes first and second coolant passage channels extending from the inlet surface to the outlet surface of the insert. This multiplication of passage channels increases the heat exchange surface area from the power module, passing through the insert walls, to the coolant. This results in improved cooling efficiency of the power module.

[0058] In another embodiment of the invention, projected onto the plane PI, a pair 330 of two adjacent motifs 33 forms a third orifice 337 disposed between the two trunks 40 of the pair 330 of the two adjacent motifs. Considered in its general form, the trunks 40 form longitudinal elements extending along the elongation axis XI between the inlet and outlet surfaces of the insert. Since the trunks are spaced apart, the inter-trunk space forms a groove. The grooves extending between the trunks form the third passage channels for the coolant and also contribute to the thermal efficiency of the insert.

[0059] Advantageously, the upper surface of the longitudinal elements is positioned directly above the electronic chips 62 of the power module. Positioning the longitudinal elements directly above the electronic chips 62 ensures a shorter thermal path between the power module and the insert. This results in improved cooling of the power module.

[0060] Figure 3 schematically represents a cross-sectional view along plane PI of the cooling insert 30 according to the invention, disposed in the coolant circulation channel. In this cross-sectional view, the insert is located between the bottom wall 9 of the receptacle 6 on one side and the closing wall 8 on the other. The insert occupies The entire available height between the closing wall and the bottom wall is used. The coolant flows through the insert in a direction XI (perpendicular to the cutting plane). From the perspective of the coolant, the insert forms a grid pattern within the channel. This grid pattern, formed by the plurality of first, second, and third flow channels, facilitates heat exchange between the insert walls and the coolant.

[0061] In [Fig. 3], the difference in width of the motifs 33 is illustrated. Considered in the section plane PI, a characteristic dimension of the trunk 40 (here its width) is dl. Moving towards the lower surface of the insert, the width of the branch decreases to dl1, which is less than dl, then to dl2, which is less than dl1, and finally to dl3, which is less than dl2. In other words, a characteristic dimension of the insert, representative of the thickness of the insert walls, decreases from the upper surface of the insert to the lower surface. For example, the trunk may have a width of 2 to 3 mm, and a passage channel may have a width of 0.5 mm (corresponding to the width dl3). As explained previously, this characteristic allows the insert to accommodate the available height in the cooling circuit channel.

[0062] The thinness of the insert walls is made possible by the manufacturing process for producing the insert 30, which will be explained below. The insert is advantageously produced by a material extrusion process. Extrusion makes it possible to have very thin insert walls (i.e., very thin channel widths), on the order of 0.5 mm (whereas a cold forming process would result in channel widths on the order of 1.8 to 2 mm).

[0063] The thermal distribution resulting from the simulation is visually illustrated by different shades of gray. In the center of the figure, the temperature at the chips 62 located at the center of the power module 20 is 136.22 °C. At the trunk 40, directly above the central chip 62, the temperature drops to 95.52 °C. Slightly lower, at one of the branches, the temperature is 84.47 °C. These temperatures are 5 °C lower than those obtained by simulating prior art insert solutions. These simulations indicate a higher level of thermal performance for the insert of the invention.

[0064] Figure 4 schematically represents a cross-sectional view in plane PI of another embodiment of the cooling insert according to the invention. In this embodiment, all the elements are identical to those previously shown. The difference lies in the shape of the lower surface of the insert. Here, the lower surface is a curved surface. In other words, the lower surface of the insert is a curve projected onto plane PL. The shape of this insert allows it to fit into a receptacle whose bottom wall is curved. Although the cross-section smaller than the insert shown above, the presence of the passage channels ensures a good level of heat exchange with the coolant.

[0065] Examples can be formed using an additive manufacturing process. A common example of additive manufacturing is 3D printing; however, other additive manufacturing methods are available. Rapid prototyping or rapid manufacturing are also terms that can be used to describe additive manufacturing processes. As used here, "additive manufacturing" generally refers to manufacturing processes in which successive layers of material(s) are arranged one on top of the other to "build" layer by layer, or "additively manufacture," a three-dimensional component.

[0066] Additive manufacturing can create complex geometries without using any type of tooling, molds, or fixtures, and with little or no waste. Instead of machining components from solid metal billets, much of which is cut out and discarded, the only material used in additive manufacturing is what is needed to shape the part.

[0067] The invention also covers a method for manufacturing a cooling insert as described above, comprising the following steps: - supply of a thermally conductive compressed material, - passage through a die having a cross-section of shape complementary to the cross-section of the cooling insert described previously in the PI section plane of the cooling insert.

[0068] This is an extrusion manufacturing process. In addition to being less expensive, the material extrusion manufacturing process makes it possible to obtain the required thinness of the cooling insert walls.

[0069] Figure 5 schematically represents the steps of a manufacturing process for a cooling device according to the invention. The manufacturing process for the cooling device 50 comprises the following steps, carried out in this order. First, step 100 is performed. A cooling insert 30, as described above, is provided. The insert 30 can be produced by one of the processes described above, by extrusion, or by additive manufacturing. It can be produced just before the manufacturing process for the cooling device, or it can be produced beforehand and stored for use just before the manufacturing of the cooling device. The cooling insert is generally complementary in shape to the shape of the channel in the cooling circuit into which it is intended to be inserted. Next, a closing wall 8 is provided.Then, a metallic bond is established between the upper surface 31 of the insert 30 and an internal surface 38 of the closing wall 8. In one embodiment, the closing wall 8 is reversed, and solder powder 39 is deposited on the internal surface 38 of the wall. The closure wall is closed, and the insert 30 is brazed onto the closure wall 8 at its internal surface 38 (step 110). Brazing is a process for joining two parts. The assembly consisting of the closure wall and the insert is placed in the furnace, resulting in the assembly in which the insert is secured to the closure wall (step 120). The closure wall 8 and the receptacle 6 are then joined. The assembly is inverted and placed against the walls 11, 12 of the receptacle 6 (step 130). More precisely, the peripheral portions of the closure wall come into contact with the upper ends of the walls 11, 12 of the receptacle. The cooling insert 30 is housed in the cooling circuit channel. Advantageously, its lower surface 32 is in contact with the bottom wall 9 of the cooling circuit channel. As explained previously, the thinness of the structures on the lower part of the insert 30 allows the insert to deform vertically to accommodate height differences between the channel and the insert. In other words, the height between the bottom wall and the upper part of the walls 11, 12 can be slightly less than the height between the peripheral portions of the closing wall and the lower surface 32 of the insert. In this case, at step 130, the insert compresses slightly to conform to the available space in the channel. Step 140 is then performed to fix the closing wall 8 to the receptacle 6. This step can be carried out by friction stir welding. Friction stir welding is also known by the English term "Friction Stir Welding" or FSW.This is a solid-state welding process that does not use filler metal. Friction stir welding involves joining two parts by bringing them to a slurry state using a rotating tool. The heat generated by the friction of the tool's shoulder causes localized softening, allowing the material to be worked. After the preheating phase, the rotating tool moves along the joint at a defined speed to complete the weld. This process is particularly well-suited for welding aluminum parts. In step 150, the cooling device 50 is thus obtained.

[0070] Such a manufacturing process has the advantage of being simplified compared to existing processes since it only includes a single friction stir welding step, the joining of the insert and the closing wall being achieved by brazing.

[0071] On the right of [Fig. 5], a variant of the closing wall 8' is schematically represented. The closing wall 8, as discussed previously, is shown first. In order to withstand the pressure exerted upon it, the closing wall 8 typically has a height 81 of between 2.5 and 5 mm. In this variant of the closing wall 8', the contact area of ​​the insert 30, i.e., the central part of the internal surface 38, is machined. In other words, the closing wall 8' has a A recess 80 has a height of 82. This results in a height 83 of the closing wall 8' in its central part of approximately 0.5 to 1 mm. The mechanical retention of the insert against the internal surface 38 of the closing wall 8' is ensured by brazing. The presence of the recess 80 contributes to improved heat transfer within the cooling device.

[0072] The invention is based on the placement of an innovative cooling insert in the cooling circuit channel of the receptacle of a cooling device. This insert has a very specific geometry: its general shape, i.e. its outer contour, follows the shape of the channel, and its internal structure, composed of passage channels with a variable and decreasing cross-section between its upper and lower surfaces, allows both optimized cooling of the cooling device and adaptation of the shape of the insert to the space allocated to it in the channel, further contributing to the optimization of cooling since, occupying the entire available cross-section in the channel, all the coolant passes through the insert.

[0073] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the features of different embodiments of the invention can be combined to carry out the invention, provided that these embodiments are not incompatible with each other.

Claims

Demands

1. Cooling insert (30) intended to be interposed between a first wall (9) and a heat source (20), the insert (30) extending between an upper surface (31) and a lower surface (32) and comprising, in a cutting plane (PI) of the insert perpendicular to an elongation axis (XI) of the cooling insert (30), a plurality of motifs (33) adjacent in the cutting plane (PI) forming first orifices (36), each motif (33) extending between a first end (34) flush with the upper surface (31) and a second end (35) flush with the lower surface (32), each motif (33) having its first end (34) of width (d1) greater than that (d2) of its second end (35).

2. Cooling insert (30) according to claim 1, wherein each motif (33) comprises: - a trunk (40) extending from the first end (34) of the motif (33) to an intermediate zone (41), and - at least two branches (42, 43), each branch extending from a first end (421, 431) connected to the intermediate zone (41) to a second end (422, 432) forming the second end (35) of the motif (33), the two branches (42, 43) of a motif (33) being intertwined.

3. Cooling insert (30) according to claim 2, wherein the second ends (422, 432) of the two branches of a pattern (33) are joined together and form a first surface (351) of the second end (35) of the pattern.

4. Cooling insert (30) according to claim 3, wherein the second ends (422, 432) of the two branches of a pattern (33) further form a second surface (352) of the second end (35) of the pattern.

5. Cooling insert (30) according to any one of claims 1 to 4, wherein a pair (330) of two adjacent patterns (33) form second orifices (336).

6. Cooling insert (30) according to claim 5, wherein a branch of a pattern is connected to a branch of an adjacent pattern.

7. Cooling insert (30) according to any one of claims 1 to 6, in which a pair (330) of two adjacent motifs (33) forms a third orifice (337) disposed between the two trunks (40) of the pair (330) of the two adjacent motifs.

8. Cooling device (50) for a power module (20), the cooling device (50) comprising a receptacle (6) which includes at least one channel for the circulation of a coolant and a closing wall (8) configured to rest against the receptacle (6) to form with said channel a circuit (10) of coolant, said power module (20) being made integral with the closing wall (8), the cooling device comprising at least one cooling insert (30) according to any one of claims 1 to 7, the power module being the heat source and the first wall being a bottom wall (9) of the channel, the cooling insert (30) being disposed in the channel between the closing wall (8) and the bottom wall (9) of the channel.

9. On-board charging device comprising at least one housing, electronic components housed in said housing and among which at least one power module (20), the housing further housing a cooling device according to claim 8.

10. A method for manufacturing a cooling insert (30) according to any one of claims 1 to 7, comprising the following steps: - supplying a thermally conductive compressed material, - passing a die having a cross-section of shape complementary to the cross-section of the cooling insert according to any one of claims 1 to 8 through the cutting plane of the cooling insert.

11. A method for manufacturing a cooling device (50) according to claim 8, comprising the following steps: - supplying a cooling insert (30) according to any one of claims 1 to 7, and supplying the closing wall (8) (step 100), establishment (steps 110, 120) of a metallic connection between the upper surface (31) of the insert (30) and an internal surface of the closing wall (8), securing (steps 130, 140) the closing wall (8) and the receptacle (6).

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