Cooling device for a power module

Abstract

The invention relates to a cooling device (10) for a power module (20) in which: - a circulation portion comprises a stack (13) of metal plates (14) including a first plate (141) and a plurality of intermediate plates (142) having recesses (15) forming channels (15A), - a mounting portion comprises a cover (17) for retaining the power module, adapted to press the power module against the first plate of the stack, and at least one mounting member (18), the cover being provided with a passage for said mounting member, this passage being adapted to be positioned opposite a receiving opening (30, 40) in the circulation portion, the cover plate having a recess (31) opposite said receiving opening, so as to create a housing (31A) into which said receiving opening opens. Figure for the abstract: 1

Description

Title of the invention: Cooling device for a power module. Technical field.

[0001] The invention relates to a cooling device for a power module. Technological background

[0002] The prior art of electrical systems, and in particular inverters comprising power modules, is known. These power modules are preferably associated with a cooling device designed to prevent heating of each power module in order to ensure its optimal operation. The cooling device typically comprises a cooling fluid circulation section against which the power module is applied.

[0003] The cooling device includes a cover which holds the power module against the circulation part of the cooling device, the cover itself being fixed for example by screwing onto the circulation part of the cooling device.

[0004] The cover and the circulation part of the cooling device have for this purpose an opening for the passage of a fixing screw.

[0005] One drawback of this arrangement is that dust or particles are generated during the step of attaching the cover to the circulation portion of the cooling device, for example, by screwing it on. This dust or these particles can escape from the cooling device and contaminate its surroundings. Summary of the invention

[0006] One idea underlying the invention is to provide a cooling device that limits the amount of dust or particles escaping when the cover retaining the power modules is attached to it, while being simple, quick and economical to produce.

[0007] According to one embodiment, the invention provides a cooling device for a power module comprising a circulation portion in which a cooling fluid is intended to circulate and a mounting portion for fixing the power module to the circulation portion, wherein: - the circulation section comprises a stack of metal plates including a first plate adapted to receive the power module and a plurality of intermediate plates having recesses providing channels for the circulation of the cooling fluid, - the fixing part includes a cover for holding the power module, adapted to press the power module against the first plate of the stack, and at least one fixing member, the cover being provided with a passage hole for said fixing member, this passage hole being adapted to be positioned opposite a receiving opening of the circulation part, for fixing the fixing part to the circulation part by means of said fixing member, said receiving opening of the circulation part being pierced through a plurality of metal plates of said stack and closed by a closing plate of the stack, the closing plate having a recess provided opposite said receiving opening, so as to create a housing into which said receiving opening opens.

[0008] Thanks to these features, the manufacturing of the cooling device is quick and dust-free. Indeed, the dust produced by tightening the fixing screw into the opening is collected in the recess of the closing plate and not expelled outside the cooling device. Furthermore, this is achieved without adding any extra parts beyond the stacked metal plates.

[0009] According to one embodiment, said closing plate comprises a portion which surrounds said recess and is pressed against one of the plates of the stack all around the opening. The recess is thus located precisely around the opening.

[0010] According to one embodiment, said recess is formed by stamping the closing plate.

[0011] According to one embodiment, said recess is formed by molding the closing plate.

[0012] According to one embodiment, each of the stack's plates is made of aluminum. This metal has a high thermal conductivity, on the order of 110 W / m.K to 200 W / mK.

[0013] According to one embodiment, the fastening member is a threaded screw and the receiving opening has a thread intended to cooperate with the threaded screw.

[0014] According to one embodiment, the fastening member is a self-threading screw and the receiving opening is unthreaded before insertion of the screw.

[0015] According to one embodiment, the cover of the fixing part is molded.

[0016] According to one embodiment, the cover of the fastening part comprises a support plate intended to press the power module against the first plate of the stack and at least one arm at the end of which is provided the opening for the passage of the fixing member.

[0017] The invention further relates to a power assembly, comprising a module of power and a cooling device as described above, the power module being disposed between the circulation part and the fixing part of the cooling device, pressed against the first plate of the stack by the fixing part.

[0018] The invention also relates to a method for manufacturing part of a cooling device as described above, according to which: - a plurality of metal plates are assembled from said stack, - the opening for access is pierced through the plurality of metal plates in said stack, - a closing plate is assembled to said plurality of plates in the stack, in such a way that the recess of the closing plate is arranged opposite said receiving opening. Brief description of the figures

[0019] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings.

[0020] Fig. 1 schematically represents a cross-sectional view along plane AA of Fig. 3 of a power assembly comprising three power modules and a cooling device.

[0021] Fig. 2 schematically represents an enlarged view of a detail of Fig. 1.

[0022] Figure 3 is a schematic top perspective representation of the assembly of the [Fig.l].

[0023] Fig. 4 is a schematic top perspective representation of the whole of Fig. 3, according to a direction of observation opposite to that of Fig. 3.

[0024] Fig. 5 is a schematic perspective representation viewed from below of the whole of Fig. 1. Description of the implementation methods

[0025] Figures 1, 3, 4, and 5 show a power assembly 1. This assembly comprises a cooling device 10 and three power modules 20. The power modules 20 are typically components arranged for converting electrical energy from direct current to alternating current or vice versa. They are thus intended to form an inverter, particularly for an electric vehicle, that is, a device arranged to convert the direct current delivered by an electric battery into alternating current to power an alternating current electric machine and vice versa.

[0026] Each power module 20 is in the form of a block of globular shape flattened parallelepiped shape. The three power modules 20 are here arranged side by side, aligned along a longitudinal direction XI of the cooling device 10 ([Fig.3]).

[0027] The cooling device here has an elongated shape along this longitudinal direction XL

[0028] The cooling device 10 includes a circulation part 11 in which a cooling fluid is intended to circulate and a fixing part 12 for fixing the power module 20 onto the circulation part 11.

[0029] The circulation part 11 comprises a stack 13 of metal plates 14 including a first plate 141 adapted to receive the power module 20 and a plurality of intermediate plates 142 having recesses 15 providing channels for the circulation of the cooling fluid ([Fig.1]).

[0030] The coolant is a liquid, for example water-based with additives for example glycol-based or any other coolant used in automobiles.

[0031] Each of the stack's plates is made of aluminum. This material ensures efficient heat exchange with the cooling fluid.

[0032] The stack 13 of metal plates 14 of the circulation part 11 further comprises a last plate 143 arranged opposite the first plate 141 in the stack.

[0033] The first plate 141 and the intermediate plates 142 are flat and have two main parallel faces connected by a peripheral edge.

[0034] A front face 141A of the first plate 141 receives each power module 20. A rear face 141B of the first plate 141 opposite its front face 141A is applied against the intermediate metal plates 142.

[0035] The main faces of the intermediate metal plates 142 are joined together.

[0036] The recesses 15 of each pair of two adjacent intermediate plates 142 placed in the stack 13 are in at least partial communication. Channels 15A are thus formed in the stack of metal plates 14 by connecting these recesses 15 ([Fig. 1]). These channels open outside the circulation section 11, so that they can be connected to a cooling fluid circulation system ([Fig. 5]). The cooling fluid circulation system injects a cooling fluid into the channels thus formed, which circulates in the channels to dissipate some of the heat contained in the circulation section and thus cool it.

[0037] The last plate 143 also has a front face 143A, at least part of which is flat and against which the rear face of the inter- plate is positioned medial 142 of stack 13 adjacent to the last plate 143.

[0038] The last plate 143 closes at least partially the channels 15A. It may have openings 151 ([Fig.5]) allowing the channels 15A to be connected to the fluid circulation system (not shown).

[0039] The fixing part 12 has a cover 17 to hold each power module 20. The cover 17 is adapted to press each power module 20 against the first plate 141 of the stack 13.

[0040] The fastening part 12 further comprises at least one fastening member 18 ([Fig.3] )•

[0041] The cover 17 is provided with at least one passage 19 for said fastening member 18.

[0042] The cover 17 of the fixing part 12 is for example molded in metal, such as aluminum.

[0043] More specifically, eight fixing elements and eight corresponding passage orifices are provided here.

[0044] Each passage opening 19 is adapted to be positioned opposite a receiving opening 30, 40 of the circulation part 11, for the fixing of the fixing part 12 on the circulation part 11 by means of said fixing member 18.

[0045] In practice, the cover 17 here has the shape of a rider with a central support plate 171 and a plurality of lateral arms 172 which extend from the central support plate 171.

[0046] The central support plate 171 extends along the longitudinal direction XI of the cooling device 10.

[0047] The central support plate 171 is intended to press the power module 20 against the circulation part 11 of the cooling device 10.

[0048] When the cover 17 is in place on the circulation part 11, the central support plate 171 extends at a distance from the first metal plate 141, generally parallel to its front face 141 A. A receiving housing for each power module 20 is thus provided between the front face 141A of the first plate 141 and the central support plate 171 of the cover 17.

[0049] The gap between the central support plate 171 and the front face 141A of the first plate 141 of the stack 13 when the fixing part 12 is fixed on the circulation part 11 is determined so that each power module 20 is pressed against the front face 141A of the first plate 141 when the fixing part 12 is fixed on the circulation part 11.

[0050] Each lateral arm 172 of the fastening part 170 extends from the central plate 171 to the front face 141A of the first metal plate 141. The shape of the lateral arms 172 dictates the gap described above between the central plate support 171 and the front face 141A of the first plate 141 of the stack 13 when the fixing part 12 is fixed on the circulation part 11.

[0051] The lateral arms 172 of the cover 17 extend on either side of the central support plate 171. Part of them extends between the power modules 20 and on either side of them. The lateral arms extending between the power modules 20 extend perpendicularly to the longitudinal axis XL. The cover 17 may also include other lateral arms 172 extending at a non-zero angle other than 90° with respect to the central plate 171. These include, in particular, the lateral arms 172 extending at each end of the central plate 171 and locking the power modules 20 at the longitudinal ends of the device.

[0052] The lateral arms 172 separate the power modules in pairs along the longitudinal direction XI and block any movement of the power modules along this longitudinal direction XL

[0053] The cover here includes for this purpose eight lateral arms 172 which frame and separate the three power modules 20.

[0054] A passage orifice 19 for the fastening member 18 is provided at the end of each lateral arm 172.

[0055] The receiving opening 30, 40 of the circulation part 11 corresponding to each passage orifice 19 of the fixing part 12 is pierced through a plurality of metal plates 141, 142 of said stack 13 and closed by a closing plate 143, 144 of the stack 13.

[0056] The closing plate 143, 144 can be the last plate 143 of the stack 13 or one 144 of the intermediate plates 142.

[0057] The closing plate 143, 144 has a recess 31 opposite said access opening 30, so as to create a housing 31A into which said access opening 30, 40 opens ([Fig. 1]). This recess 31 corresponds to a hollow in the front face 143A of the closing plate 143, 144 ([Fig. 2]).

[0058] Housing 31A delimits an interior space which extends in line with the reception opening 30, 40.

[0059] The closing plate 143, 144 further comprises a portion that surrounds said recess 31 and is pressed against one of the stacking plates all around the receiving opening (30). The portion extending around the recess forms, for example, a flat collar that is pressed against the rear face of the intermediate plate 142 adjacent to the closing plate. Preferably, the remainder of the front face 143A of the closing plate, excluding the recess, is flat and pressed against the rear face of the intermediate plate adjacent to the closing plate.

[0060] The recess 31 is formed for example by stamping the closing plate 143, 144.

[0061] Alternatively, the recess is formed by molding the closing plate.

[0062] The fastening member 18 is, for example, a threaded screw and the receiving opening 30, 40 features an 18A thread ([Fig.2]) intended to cooperate with the threaded screw.

[0063] Alternatively, the fastening member is a self-threading screw and the receiving opening is unthreaded before insertion of the self-threading screw.

[0064] Alternatively, the fastening member may include a snap-on part cooperating with an opening or a crimping or riveting system.

[0065] The cooling device 10 thus includes, integrated into the stack of metal plates 14 forming the circulation part 11 of the cooling fluid, the housing 31A which closes the reception opening 30, 40 of the circulation part 11 in which the fixing member is fixed.

[0066] Dust or particles generated by the insertion of the fastening member 18 into the receiving opening 30, 40 cannot escape from the circulation portion 11 of the cooling device. This dust or these particles are retained inside the housing 31 A. Thus, the environment of the cooling device remains clean, free from dust or particles.

[0067] Moreover, this is achieved in a particularly simple, quick, and economical manner. Indeed, no additional elements are used to retain dust and particles. The housing is formed by one of the metal plates of the stack of metal plates 14 of the circulation section 11.

[0068] In particular, according to one embodiment, part of a cooling device is manufactured according to the following steps:

[0069] - a plurality of metal plates 14 are assembled from said stack 13, for example by brazing,

[0070] - the receiving opening 30, 40 is pierced through the plurality of metal plates 14 said stack 13,

[0071] - a closing plate 143, 144 is assembled having a recess 31 to said plurality of plates of the stack 13, such that the recess 31 of the closing plate 143, 144 is arranged opposite said reception opening 30, 40.

[0072] Thus, each reception opening is drilled in one go, through the already assembled metal plates.

[0073] Housing 31A is formed by assembling the metal plates together.

[0074] In addition, other openings through a plurality of metal plates of the stack can also be closed by a closing plate comprising a recess so as to form a housing extending these other openings.

[0075] Although the invention has been described in connection with several particular embodiments, it is quite clear that it is by no means limited to them and that it includes all the technical equivalents of the means described and their combinations if these fall within the scope of the invention.

[0076] A power assembly comprising a cooling device and three power modules has been described here. The power assembly may also include a cooling device and at least one power module. Preferably, it comprises a cooling device and between one and N power modules, where N is an integer. For example, N is equal to 3, 5, 6, or 10. Each power module may consist of a module comprising a set of electronic components, including transistors, for example, MOS transistors, forming switches. Alternatively, a power module may consist of a discrete component such as an IGBT transistor. Alternatively still, a power module may be replaced by an excitation module, in particular an excitation module for a rotor coil of a rotating electrical machine.

[0077] The use of the verb "comprise", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0078] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Demands

1. A cooling device (10) for a power module (20) comprising a circulation portion (11) through which a cooling fluid is intended to circulate and a mounting portion (12) for fixing the power module (20) to the circulation portion (11), wherein: - the circulation portion (11) comprises a stack (13) of metal plates (14) including a first plate (141) adapted to receive the power module (20) and a plurality of intermediate plates (142) having recesses (15) providing channels (15A) for the circulation of the cooling fluid, - the mounting portion (12) comprises a cover (17) for retaining the power module (20), adapted to press the power module (20) against the first plate (141) of the stack (13), and at least one fastening member (18), the cover (17) being provided with a passage orifice (19) for said fastening element (18),this passage opening (19) being adapted to be positioned opposite a receiving opening (30, 40) of the circulation section (11), for the fixing of the fixing section (12) onto the circulation section (11) by means of said fixing member (18), said receiving opening (30, 40) of the circulation section (11) being pierced through a plurality of metal plates (141, 142) of said stack and closed by a closing plate (143, 144) of the stack (13), the closing plate (143, 144) having a recess (31) formed opposite said receiving opening (30), so as to create a housing (31 A) into which said receiving opening (30, 40) opens.

2. Cooling device (10) according to claim 1, wherein said closing plate (143, 144) has a part which surrounds said recess and is pressed against one of the plates of the stack 142) all around the receiving opening (30, 40).

3. Cooling device (10) according to any one of claims 1 and 2, wherein said recess (31) is formed by stamping the closing plate (143, 144).

4. Cooling device (10) according to any one of claims 1 to 3, wherein said recess (31) is formed by molding the closing plate (143, 144).

5. Cooling device (10) according to any one of claims 1 to 4, in which each of the metal plates (14) of the stack (13) is made of aluminium.

6. Cooling device (10) according to any one of claims 1 to 5, wherein the fastening member (18) is a threaded screw and the receiving opening (30, 40) has a thread for cooperating with the threaded screw.

7. Cooling device (10) according to any one of claims 1 to 5, wherein the fastening member (18) is a self-threading screw and the receiving opening (30, 40) is unthreaded prior to insertion of the screw.

8. Cooling device (10) according to any one of claims 1 to 7, wherein the cover (17) of the fastening part (12) is molded.

9. Cooling device (10) according to any one of claims 1 to 8, wherein the cover (17) of the fixing part (12) includes a support plate (171) for pressing the power module (20) against the first plate (141) of the stack (13) and at least one arm (172) at the end of which is provided the passage orifice (19) of the fixing member (18).

10. Power assembly (1), comprising a power module (20) and a cooling device (10) according to any one of the preceding claims, the power module (20) being disposed between the circulation part (11) and the fixing part (12) of the cooling device (10), pressed against the first plate (141) of the stack (13) by the fixing part (12).

11. A method for manufacturing part of a cooling device (10) according to claim 1, wherein: - a plurality of metal plates (14) of said stack (13) are assembled, - the receiving opening (30, 40) is drilled through the plurality of metal plates (14) of said stack (13), - a closing plate (143, 144) is assembled to said plurality of plates (14) of the stack (13), such that the recess (31) of the closing plate (143, 144) is arranged opposite said receiving opening (30, 40).

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