Thermal regulation device, and charging device comprising a thermal regulation device

Abstract

Thermal regulation method and thermal regulation device, in particular for a motor vehicle The present invention relates to a device (1) for thermal regulation, in particular for cooling, for an electrical component (2) likely to release heat during its operation, in particular for an electrical energy storage module, this device comprising a first plate (2) and a second plate (3) assembled with the first plate each delimited by edges, to form together a plurality of channels (5) for circulation of a heat transfer fluid, in particular a refrigerant fluid, the plurality of channels defining a channel zone (6), at least one of the plates being stamped in order to form a part of the walls of the channels, the assembly of the two plates being carried out by laser welding (7) at the walls of the channels,the device being characterized in that an area defining at least partially the perimeter of the channel area comprises an assembly means (8) different from laser welding (7) by transparency, the different assembly means (8) is chosen from laser welding with a material filler wire, bonding, friction stir welding, or a combination thereof. Figure for the abstract: Fig. 2,

Description

Title of the invention: Thermal regulation device, and charging device comprising a thermal regulation device

[0001] The present invention relates to a thermal regulation device, in particular a cooling device, in particular for an electrical component likely to release heat during its operation, in particular a device for cooling at least one battery or battery cells of a vehicle, for example a motor vehicle.

[0002] The vehicle can be land, sea or air.

[0003] The components that may be concerned by the present invention may be electrical energy storage elements, in particular battery elements, or power electronics, for example, but not limited to, semiconductors, such as diodes or transistors. They could also be computer server components.

[0004] Electrical or electronic systems, for example electrical energy storage devices within a motor vehicle or computer servers, may be subject to significant constraints due to a need to power an element requiring a significant amount of energy or due to the need to carry out significant processing of information in a minimum amount of time. Thus, when these electrical or electronic systems are heavily used, they are likely to release a significant amount of heat and therefore reach high temperatures which are detrimental to the lifespan of said electrical or electronic systems.

[0005] In order to limit the temperature of electrical or electronic systems, it is known to provide cooling devices associated with these systems. Such cooling devices are arranged in the vicinity of the parts of the electrical or electronic system releasing heat and are traversed by a cooling fluid whose temperature allows an exchange of calories with these parts and the cooling of the latter. These cooling devices may in particular be plate devices, obtained by an assembly of at least two stamped plates welded together in order to form channels between said plates, said channels allowing the circulation of the cooling fluid.

[0006] The invention relates in particular to plate heat exchangers intended for the circulation of a refrigerant fluid allowing the cooling of hybrid or electric vehicle batteries.

[0007] Industrially, these exchangers are generally made from me- metals, and are assembled by brazing.

[0008] The brazing process, although very widespread in industry today, has disadvantages, in particular that of the carbon footprint of such a manufacturing process, and so much so that in order to reduce, in particular, the electrical consumption and therefore the emissions generated indirectly by such a process, alternative solutions are gradually being proposed for joining two plates, one of them being the assembly of the two plates by welding, in particular by laser welding.

[0009] The laser welding process has several advantages. Indeed, such a process is less energy-intensive and less polluting than brazing welding. It ensures a reliable, leak-free joint, particularly in straight lines. However, heat exchangers include other types of trajectories, such as turns, loops or other complex trajectories.

[0010] These trajectories, where the direction of the laser beam changes, are more sensitive to welding defects, such as cracks, which can lead to leaks.

[0011] This results in a need to obtain robust and leak-free heat exchangers, using a more ecological, rapid and reliable process.

[0012] The present invention aims to at least partially overcome one or more of the aforementioned drawbacks by proposing a heat exchanger, manufactured using a combination of several assembly technologies, in order to ensure the sealing and mechanical strength requirements, while reducing electricity consumption and the production of pollutants compared to a brazing process.

[0013] The invention thus relates to a thermal regulation device, in particular a cooling device, for an electrical component likely to release heat during its operation, in particular for an electrical energy storage module, this device comprising a first plate and a second plate assembled with the first plate each delimited by edges, to form together a plurality of circulation channels for a heat transfer fluid, in particular a refrigerant fluid, the plurality of channels defining a channel zone, at least one of the plates being stamped in order to form a part of the walls of the channels, the assembly of the two plates being carried out by laser welding by transparency at the level of the walls of the channels, the device being characterized in that an area defining at least partially the perimeter of the channel area comprises an assembly means different from laser welding by transparency, the different assembly means being chosen from laser welding with a material filler wire, bonding, friction stir welding, or a combination thereof.

[0014] We understand by "the assembly carried out by laser welding at the level of the zone of channels” that the two plates are fixed together at the channels so as to allow circulation of heat transfer fluid between the two parts.

[0015] Advantageously, this assembly means, different from transparent laser welding, makes it possible to improve the mechanical strength and reliability of the device while retaining a certain ease of manufacture by overcoming the drawbacks of transparent laser welding.

[0016] The charging device may further comprise one or more of the following features described below, taken separately or in combination.

[0017] According to a feature of the invention, the zone comprising an assembly means (8) defines the entire perimeter of the channel zone.

[0018] According to a feature of the invention, at least one wall of the channels defines the perimeter of the channel zone. The term "perimeter of the channel zone" then means the wall of the channels furthest from the center of the device, and in particular the part of the wall of the channels of a plate which is joined to the other plate.

[0019] According to a feature of the invention, the perimeter of the channel zone, preferably the at least one channel wall defining at least a portion of the perimeter of the channel zone, comprises a weld formed by a friction stir weld or a bonding joint.

[0020] According to a feature of the invention, the perimeter of the channel zone, preferably the at least one channel wall defining at least part of the perimeter of the channel zone, comprises a weld formed by a friction stir weld.

[0021] According to a feature of the invention, the perimeter of the channel zone, preferably the at least one channel wall defining at least part of the perimeter of the channel zone, comprises a glued junction.

[0022] According to a feature of the invention, the perimeter of the channel zone, preferably the at least one stamped wall of channels defining at least part of the perimeter of the channel zone defines the entire perimeter of the channel zone and forms a sealing channel, the sealing channel comprising glue forming a seal.

[0023] According to a feature of the invention, the device comprises an additional weld, preferably by laser, bordering the external side of the junction of the perimeter of the channel zone by the different assembly means.

[0024] According to a feature of the invention, the additional welding, preferably by laser, joins at least the edges of at least one plate to the other plate.

[0025] The invention also proposes a method of assembling two plates to obtain a thermal regulation device, in particular a cooling device, for an electrical component likely to release heat during its operation, in particular for an electrical energy storage module, the method being characterized in that it comprises the following steps, - Providing two plates each delimited by edges, at least one of the plates being stamped in order to form a part of the walls of the channels so as to form with the other plate together a plurality of circulation channels for a heat transfer fluid, in particular a refrigerant fluid, the plurality of channels defining a channel zone, - Laser welding, preferably by transparency, of the two plates at the walls between the channels in contact with the second plate to form the channel zone, - Then joining the perimeter of the channel zone of one plate to the other plate by an assembly means different from laser welding by transparency, preferably by joining at least one wall of the channels defining said perimeter.

[0026] According to a feature of the invention, the method further comprises a third joining step, by an additional weld, preferably by laser, surrounding the junction of the perimeter of the channel zone by the different assembly means, in particular so as to weld edges of at least one of the two plates on the other plate, preferably by laser welding.

[0027] According to a feature of the invention, the method further comprises a step of placing glue forming a seal in a stamped wall of channels defining the entire perimeter of the channel zone and forming a sealing channel, so that the glue is compressed by the two plates during their assembly, in particular followed by a step of heat treatment of the glue in the stamped wall once the plates of the device are assembled and said glue is compressed.

[0028] According to a feature of the invention, the method further comprises a step of heat treatment of the glue in the stamped wall once the plates of the device have been assembled and said glue has been compressed.

[0029] DETAILED DESCRIPTION OF THE FIGURES

[0030] Other characteristics and advantages of the invention will appear more clearly on reading the following description, given as an illustrative and non-limiting example, and the appended drawings among which:

[0031] - [Fig.l] illustrates, schematically and partially, a cooling device according to development according to the prior art;

[0032] - [Fig.2] illustrates, schematically, a device according to a first mode of realization embodiment of the invention according to a perspective view.

[0033] - [Fig.3] illustrates, schematically and partially, a detail of the device according to a second embodiment of the invention, in sectional view;

[0034] - [Fig.4] illustrates, schematically and partially, a detail of the device according to a third embodiment of the invention, in sectional view.

[0035] - [Fig.5] illustrates, schematically and partially, a detail of the device according to a fourth embodiment of the invention, in sectional view.

[0036] THERMAL REGULATION DEVICE

[0037] The invention relates in particular to the thermal regulation device 3 described in more detail below. It comprises a thermal regulation device, in particular a cooling device, for an electrical component (2) capable of releasing heat during its operation, in particular for an electrical energy storage module, this device comprising a first plate (2) and a second plate (3) assembled with the first plate each delimited by edges, to form together a plurality of channels (5) for circulation of a heat transfer fluid, in particular a refrigerant fluid, the plurality of channels defining a channel zone (6), at least one of the plates being stamped in order to form a part of the walls of the channels, the assembly of the two plates being carried out by laser welding by transparency (7) at the walls of the channels, the device being characterized in that an area defining at least partially the perimeter of the channel area comprises an assembly means (8) different from laser welding (7) by transparency, the different assembly means (8) is chosen from laser welding with a material filler wire, bonding, friction stir welding, or a combination thereof.

[0038] Small communication leaks between the channels can be accepted, since there is no loss of fluid to the outside of the cooler, only an insignificant decrease in thermal homogeneity at the surface of the battery. External leaks, regardless of their location, are not acceptable. One of the handicaps of transparent laser welding is that perfect contact is required between the surfaces to be welded.

[0039] The battery welding is typically done from the inside of the cooler to the outside of the cooler, in order to be able to absorb the expansions and deformations of the plates caused by the previous welds. This means that the surface of the plates at the perimeter of the channel can be deformed or it is difficult to keep the two plates in contact. The risk of leaks is then increased.

[0040] The mechanical constraints concerning battery coolers are increasing, and the mechanical behavior of the cooler has become an important subject.

[0041] One of the internal requirements is to keep the manufacturing cycle time of the cooler as short as possible, so in all cases the junction between the channels is made by transparent laser welding. The invention is applied on the perimeter of the plate or in specific areas. The advantage of the present invention is therefore to keep the advantages of transparent laser welding while by freeing itself from its drawbacks.

[0042] The charging device may further comprise one or more of the following features described below, taken separately or in combination.

[0043] The dimensions of the weld bead may be between 0.5mm and 1.5mm, preferably 0.75mm and 1.25mm.

[0044] The location of the junction joining the edges of one plate to the other plate is a function of its position relative to said edges and depends on the position of the edges of the channels relative to the edges of the flat plate. This distance between the junction and the nearest edge of the plate can vary from 0 to 5 cm, preferably 0.1 cm to 3 cm, more preferably 0.1 cm to 1 cm.

[0045] It is understood here that the “edges” of the plate can be flat or stamped.

[0046] It is understood that "laser angle welding" or fillet joint welding in English means a weld without adding material between the edge of a plate, preferably the stamped plate, and a flat area of the other plate, preferably the upper flat plate. The laser is used to melt the material of the plates to make the weld between them.

[0047] In the case of laser welding with a filler wire, or filler wire welding in English, the welding can be carried out with the same position of the plates for example, but a wire of material is melted in order to provide the material which will form the weld bead.

[0048] In some embodiments, one of the plates comprises a deformation forming a fold towards the second plate, for example a raised edge. This advantageously reduces the risks of dust, debris or humidity being able to enter between the two plates.

[0049] This also advantageously makes it possible to reduce the effects of deformations due to the laser welding junction carried out in the channel zone.

[0050] The deformation of the first stamped plate in order to form the channels is generally carried out by stamping, with a deformation. The length of the deformation, in the direction of the second plate, to which the first plate is intended to be joined, must not exceed the thickness of said second plate. When joining the plates, the laser welding creates stress constraints, which is why it is advantageous to have strong external welds.

[0051] In certain embodiments, the laser welding is done from the inside of the plate such as the center, towards the outside, in order to be able to best manage said stress constraints created by the deformation then the welding of the plates.

[0052] The glue can be chosen from types of glues such as PU (polyurethane), EPOXI or methacrylate.

[0053] In some embodiments, the glue is crosslinked, for example, by treatment with the temperature after its application in the device, the glue being made of EPDM, NBR or FKM.

[0054] In some embodiments, the laser transparency welding is first performed between the channels, and then the second additional joining means is performed, such as for example friction stir welding on the perimeter of the plate. Friction stir welding is a solid-state welding process that involves joining two parts together by bringing them into a pasty state using a rotating pin. An example of such a process involves a cylindrical tool with a shoulder and a coaxial pin rotating at a constant speed along the contact line between the parts to be welded, causing the materials to "soften" and become pasty. The tool then penetrates the joint plane and thoroughly mixes the materials. Complete joining is achieved as the tool advances, gradually moving across the entire area to be welded. The maximum temperatures reached during the process are lower than the melting temperature of the material: the friction stir welding process is therefore a solid-state welding process.

[0056] In certain embodiments, the device comprises a welding path at least partially delimiting the fluid circulation zone and at least one weld bead, corresponding for example to the end of the welding path, is produced in contact with the welding path at at least one contact point, the welding path and the weld bead having a different curvature relative to each other at said contact point.

[0057] Thanks to the implementation of the welding bead, the sealing of the cooling device is assured with certainty, and the stopping of the laser beam performing the welding does not alter the sealing of the cooling device. As will be described below, the welding bead can thus consist of an additional welding operation which surrounds one end of the welding trace and therefore ensures sealing around an area potentially presenting leaks formed by the end of the welding trace, or else consist of an extension of the welding trace to relocate to a non-problematic area, because it is far from the fluid circulation area, the risk of leakage potentially due to the stopping of the laser beam.

[0058] In some embodiments, the weld bead is established at least partially in contact with the weld trace and constitutes an additional weld reinforcing the sealing of the cooling device. In other words, the weld bead doubles the sealing of the cooling device by sealing the weld trace. Thus, the cooling fluid cannot flow through a potential weld trace because the weld bead either closes the weld trace, by surrounding a potential point of weakness within the weld trace, or extend the welding path to relocate this potential point of weakness. In each of these cases, the seal is ensured and certified thanks to the different curvature of the weld bead compared to that of the welding path at the point of contact between the weld bead and the welding path.

[0059] According to certain embodiments, the weld bead forms an extension of the welding path. In other words, the weld bead is implemented in the continuity of the welding path and the point of contact between the welding path and the weld bead corresponds to the junction between the end of the welding path and the start of the weld bead. It is in particular thanks to this extension by the weld bead that the sealing of the cooling device is ensured.

[0060] As previously discussed, the curvature is different between the welding path and the weld bead. Thus, from the point of contact, the weld bead deviates from a path established by the welding path.

[0061] According to certain embodiments, the welding trace has a closed profile, the welding bead having a free end at a distance from the closed profile of the welding trace.

[0062] For example, the closed profile as defined by the welding path may correspond to the contour of the plates in order to prevent the cooling fluid from flowing out of the cooling device. Generally speaking, the closed profile may define an area where the cooling fluid must be contained, or conversely an area where the cooling fluid, for various reasons, must not penetrate. The welding bead extends to the free end which deviates from the closed profile thanks to the different curvature compared to that of the welding path. This extension forming a free end makes it possible to interrupt the laser beam at a distance from the end of the welding path and thus not to generate sealing defects as mentioned previously.

[0063] [Fig.l] shows a prior art thermal regulation device 1 comprising a set of battery cells 12 to be cooled, for example arranged in two or more rows, which are in thermal contact with an upper plate 3 of the thermal regulation device 1. The device 1 comprises a stamped plate 2 and a flat plate 3 between which heat transfer fluid passes through channels. The majority of devices of this type are assembled by brazing in large furnaces, which has several drawbacks, in particular the cost of such furnaces and their carbon footprint during operation.

[0064] [Fig. 2] shows an exemplary embodiment of the thermal regulation device 1 comprising a first plate, preferably stamped 2 and a second plate, preferably flat 3. The channels 40 of the channel zone 4 are visible and are configured to comprise a heat transfer fluid which flows through said channels 40. fixing of one plate to the other is carried out at the channel area 4 by transparent laser welding, while an assembly means (8) different from transparent laser welding (7) joins one plate (2, 3) to the other plate (2, 3) at the perimeter of the channel area.

[0065] In certain embodiments, as shown by way of example and in a non-limiting manner in [Fig. 3], the stamped plate 2 and the flat plate 3 are joined by angle laser welding, also called “Fillet joint Laser Welding”, or by laser welding with a material filler wire, also called “Filler wire Laser Welding” at the edges of a plate, here the stamped plate 2.

[0066] Thus, in certain embodiments, the stamped plate 2 and the flat plate 3 are joined by an assembly means (8) other than laser welding (7) at the edges of a plate, here the stamped plate 2 on another plate, here the flat plate 3, on a line distant from the edge of said flat plate 3.

[0067] The flat plate 3 thus extends beyond the edges of the other stamped plate 2.

[0068] Advantageously, this makes it possible to reduce the weight of the device, because the plate whose edges are fixed to the other plate is smaller than the other. In addition, this makes it possible to use the larger plate as a shield to protect the junction from some of the environmental impurities, in order to improve the corrosion resistance.

[0069] In some embodiments, the second plate extends beyond the edges of the first plate (2) by a length of at least 1mm, preferably at least 1.5mm.

[0070] This advantageously makes it possible in particular to reduce the weight of the device while benefiting from protection against corrosion, and this in an optimal manner.

[0071] In certain embodiments, as shown by way of example and in a non-limiting manner in [Fig. 4], one of the two plates comprises around the channel zone a stamped portion 8, for example the stamped portion plate 2.

[0072] Said stamped part 8 can thus comprise an adhesive element 10, for example glue, in order to ensure the junction of the two plates and the sealing of the assembly.

[0073] In certain embodiments (not shown), the device comprises an adhesive element 10, for example glue, without comprising an additional stamping 8.

[0074] In certain embodiments, as shown by way of example and in a non-limiting manner in Figures 4 and 5, one of the two plates, for example the stamped plate 2, comprises around the channel zone a stamped portion 11 forming the perimeter of the channel zone, the device comprising a seal 9 or an adhesive 10 forming a seal 9, compressed between the two plates (2, 3), the seal 9 being placed in the space between the two plates (2, 3) formed by the stamped portion 11.

[0075] The stamped part 11 is preferably bordered on at least one side by an additional laser weld joining the two plates. Said junction may be located between the sealing gasket 9 and the edge of at least one of the plates, and may for example be produced by transparent laser welding.

[0076] In certain embodiments, the length e of the joining means 8 formed by a stamping 11 comprising an adhesive 10 or a seal 9 and the length e of the additional laser weld located between the seal 9 and the edge of at least one of the plates are greater than 3 mm.

[0077] In some embodiments, the height of the seal 9 is at least 1.5 mm.

[0078] It is understood that the lengths eb e2, e3, e4, e5, and e6 are measured at a given point in the direction perpendicular to the main direction in which it extends at this point.

[0079] In some embodiments, the height of the stamping 11 is at least 3 mm.

[0080] The internal structure of the seal 9 can be modified after its positioning in the stamping 11, for example by heat treatment. List of reference signs

[0081] 1. thermal regulation device 2. first plate, stamped 3. second plate, flat 4. canal area 40. channel 5. Deformation forming fold 6. Connectors 7. Laser welding by transparency 8. Different means of assembly 9. gasket 10. Adhesive 11. stamped 12. Element, Storage Device, Electrical Component E. Fluid inlet S. Fluid outlet

Claims

Claims

1. Device (1) for thermal regulation, in particular for cooling, for an electrical component (2) likely to release heat during its operation, in particular for an electrical energy storage module, this device comprising a first plate (2) and a second plate (3) assembled with the first plate each delimited by edges, to form together a plurality of channels (5) for circulation of a heat transfer fluid, in particular a refrigerant fluid, the plurality of channels defining a channel zone (6), at least one of the plates being stamped in order to form a part of the walls of the channels, the assembly of the two plates being carried out by laser welding by transparency (7) at the walls of the channels, the device being characterized in that a zone defining at least partially the perimeter of the channel zone comprises an assembly means (8) different from the laser welding (7) by transparency,the different assembly means (8) is chosen from laser welding with a filler wire, gluing, friction stir welding, or a combination thereof.,

2. Device (1) for thermal regulation, according to the preceding claim, in which at least one wall of the channels defines the perimeter of the channel zone.

3. A thermal regulation device (1) according to any preceding claim, wherein the perimeter of the channel area, preferably the at least one channel wall defining at least part of the perimeter of the channel area, comprises a weld formed by friction stir welding.

4. Device (1) for thermal regulation, according to one of the preceding claims, in which the perimeter of the channel zone, preferably the at least one channel wall defining at least part of the perimeter of the channel zone comprises a glued junction.

5. A thermal regulation device according to any preceding claim, wherein the perimeter of the channel area, preferably the at least one stamped wall of channels defining at least part of the perimeter of the channel area, defines the entire perimeter of the channel area and forms a sealing channel, the sealing channel comprising glue forming a seal.

6. A thermal regulation device according to any preceding claim, wherein the device comprises an additional weld, preferably by laser, bordering the outer side of the junction of the perimeter of the channel area by the different assembly means.

7. Thermal regulation device, according to one of the preceding claims, in which the additional welding, preferably by laser, joins at least the edges of at least one plate to the other plate.

8. Method for assembling two plates to obtain a thermal regulation device, in particular a cooling device, for an electrical component likely to release heat during its operation, in particular for an electrical energy storage module, the method being characterized in that it comprises the following steps, - Providing two plates each delimited by edges, at least one of the plates being stamped in order to form a part of the walls of the channels so as to form with the other plate together a plurality of circulation channels for a heat transfer fluid, in particular a refrigerant fluid, the plurality of channels defining a channel zone, - Laser welding by transparency, of the two plates at the walls between the channels in contact with the second plate to form the channel zone,- Then joining the perimeter of the channel area of one plate to the other plate by an assembly means other than laser welding by transparency, preferably by joining at least one wall of the channels defining said perimeter.,

9. Assembly method according to the preceding claim, which further comprises a third joining step, by an additional weld, preferably by laser, surrounding the junction of the perimeter of the channel zone by the different assembly means, in particular so as to weld edges of at least one of the two plates on the other plate, preferably by laser welding.

10. Assembly method according to one of claims 8 to 9, which further comprises a step of placing glue forming a seal in a stamped wall of channels defining the entire perimeter of the channel zone and forming a sealing channel, so that the glue is compressed by the two plates during their assembly, in particular followed by a step of heat treatment of the glue in the stamped wall once the plates of the device are assembled and said compressed glue.

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