FR3159008A1 - Structure with circulation of heat transfer fluid - Google Patents

Abstract

Title: Heat Transfer Fluid Circulation Structure The invention relates to a heat transfer fluid circulation structure (1) configured in particular to form a thermal regulation device (100) for cooling and/or heating components whose operation is sensitive to temperature, these components being intended in particular for energy storage and possibly being battery cells, the heat transfer fluid circulation structure (1) comprising at least one heat transfer fluid circulation channel (10) formed between a first plate (3) and a second plate (5) welded together, along at least one laser weld line (4), the channel (10) having at least one dead zone (8) at a junction between the first plate (3) and second plate (5), the dead zone (8) being filled with a filling material (20) distinct from the materials of the first plate (3) and second plate (5). Abstract: Figure 1

Description

Structure with circulation of heat transfer fluid

The present invention relates to a structure for circulating heat transfer fluid, in particular configured to form a thermal regulation device for cooling and/or heating components, as well as a method for manufacturing such a structure for circulating heat transfer fluid.

It is currently known that the thermal regulation of batteries and battery packs, particularly in the automotive sector and even more particularly in electric and hybrid vehicles, is an important point because if the batteries are subjected to temperatures that are too cold, their autonomy can decrease significantly, and if they are subjected to temperatures that are too high, there is a risk of thermal runaway which can lead to the destruction of the battery.

In order to regulate the temperature of the batteries, it is known to add a temperature control device to the battery module. These devices generally use heat transfer fluids circulating, for example by means of a pump, in circulation channels. Among the heat transfer fluids, glycol water can be chosen. The cooling of motor vehicle batteries is done using heat exchangers which are formed by the assembly of two plates. Said circulation channels pass in particular under or inside a heat exchanger plate in direct contact with the batteries.

One of the heat exchanger plates is called the "base plate" (or "base plate" in English) which is generally flat, and the other plate is called the "channel plate" (or "channel plate" in English) which has shapes allowing to define with the base plate, one or more circulation channels for the heat transfer fluid (glycol water). It should be noted that this type of heat transfer fluid (glycol water) can generate significant corrosion, in certain situations, within the channel between the plates. These plates are generally assembled by brazing. However, this type of plate assembly by brazing requires a furnace which consumes a large amount of energy and therefore results in a high CO2 footprint. In addition, brazing can lack flexibility or precision during operations.

The invention aims to propose a structure with circulation of heat transfer fluid which remedies at least some of the problems mentioned above.

The invention thus relates to a heat transfer fluid circulation structure configured in particular to form a thermal regulation device for cooling and/or heating components whose operation is sensitive to temperature, these components being in particular intended for energy storage and possibly being battery cells, the heat transfer fluid circulation structure comprising at least one heat transfer fluid circulation channel formed between a first plate and a second plate welded together, along at least one laser welding line, the channel having at least one dead zone at a junction between the first plate and second plate, the dead zone being filled by a filling material distinct from the materials of the first plate and second plate.

The invention is advantageous in that laser welding consumes less energy than brazing, which requires a furnace that consumes a large amount of energy. The invention thus makes it possible to reduce the CO2 footprint for the manufacture of the structure with circulation of heat transfer fluid. Laser welding also allows for greater precision in the control of the weld lines along the channel(s), as well as better mechanical strength of the assembly. The invention also makes it possible, thanks to the filling material that fills the dead zone, to significantly reduce the risk of corrosion at the junction between the first plate and second plate. Indeed, in the absence of such an additional filling material, the dead zone could see stagnant heat transfer fluid accumulate and this stagnant heat transfer fluid could cause corrosion at this location. This dead zone, which would be left unfilled, can also be an air capture zone that would prevent a total vacuum from being created in the channel during the manufacture of the structure with circulation of fluid. Thanks to the invention, the risk of corrosion or the presence of unwanted air bubbles in the channel is avoided.

According to one aspect of the invention, the filling material is part of a layer present on at least one of the first plate and second plate.

For example, the filler material is part of a layer deposited on the first plate.

Alternatively, the filler material is part of a layer deposited on the second plate.

According to one aspect of the invention, the layer of material extends between two parallel longitudinal edges of the channel.

According to one aspect of the invention, this layer overflows into the dead zone(s) present within the channel, at the junction between the first plate and second plate.

According to one aspect of the invention, instead of a layer, the filling material forms a strip that runs along the junction between the first plate and the second plate. According to one aspect of the invention, the strip may be preformed so that the strip can be handled as a separate piece. For example, during manufacture, the strip may be placed on the junction between the plates. The strip may be distinguished from a layer by the fact that the layer is formed by depositing the filling material (which may, for example, be fluid enough to be spreadable) on one of the plates. Furthermore, the strip may be of lesser width than the layer, which preferably extends across the entire width of the channel.

According to one aspect of the invention, for the canal, there are two distant bands of filling material which run respectively along two parallel longitudinal edges of the canal.

According to one aspect of the invention, the filling material is a material which has undergone fusion by exposure to heat released during laser welding.

According to one aspect of the invention, the filling material is thus a material which has cooled following fusion during the laser welding process.

According to one aspect of the invention, the filling material is configured to reinforce the sealing of the channel, at the junction of the first and second plates, with respect to the heat transfer fluid which circulates in this channel.

According to one aspect of the invention, the filling material is an aluminum-based protective material of type 7072 or 1050.

According to one aspect of the invention, the filling material is a covering material (or “cladding” in English), notably chosen from a covering material of type 4343, 4045, 4047.

According to one aspect of the invention, the dead zone has, in a cross-section of the channel, a wedge profile formed at the junction of the first and second plates.

According to one aspect of the invention, the corner profile of the dead zone is for example substantially triangular.

According to one aspect of the invention, the filling material fills this corner profile.

According to one aspect of the invention, the filling material forms a meniscus, convex or concave, on one side of the canal.

According to one aspect of the invention, this meniscus is for example similar to a meniscus obtained during a brazing process.

This meniscus is formed during laser welding. The welding laser provides heat to melt the filler material, which then fills the dead zone, creating the meniscus.

The shape of the filling material thus makes it possible to eliminate dead zones which may be areas subject to corrosion problems and/or which may be unwanted air bubble traps.

According to one aspect of the invention, the filling material has a thickness of between 5% and 10% of the thickness of the plate on which the filling material is present.

According to one aspect of the invention, the filling material runs along the canal along its entire length.

According to one aspect of the invention, the first plate and second plate are made of aluminum.

According to one aspect of the invention, one of the plates is called a "base plate" (or "base plate" in English) which is generally flat, and the other of the plates is called a "channel plate" (or "channel plate" in English) which has shapes making it possible to define with the base plate, one or more circulation channels for a heat transfer fluid.

The invention also relates to a thermal regulation device for cooling and/or heating components whose operation is sensitive to temperature, these components being in particular intended for energy storage and possibly being battery cells, thermal regulation device comprising a structure for circulating heat transfer fluid as mentioned above, this structure for circulating heat transfer fluid comprising a face arranged to be able to place a component thereon.

The invention also relates to a cooled component system comprising a heat transfer fluid circulation structure as mentioned above, and at least one component placed on one face of the heat transfer fluid circulation structure.

• déposer sur l’une au moins des première plaque et deuxième plaque, un matériau de comblement, notamment sous la forme d’une couche,
• souder par laser les première plaque et deuxième plaque pour former au moins une ligne de soudure laser, la zone morte étant comblée par le matériau de comblement suite à une fusion de ce matériau de comblement.

The invention also relates to a method for manufacturing a heat transfer fluid circulation structure configured in particular to form a thermal regulation device for cooling and/or heating components whose operation is sensitive to temperature, these components being in particular intended for energy storage and possibly being battery cells, the heat transfer fluid circulation structure comprising at least one heat transfer fluid circulation channel formed between a first plate and a second plate, the channel having at least one dead zone at a junction between the first plate and second plate, the method comprising the following steps:

• depositing on at least one of the first plate and second plate, a filling material, in particular in the form of a layer,
• laser welding the first plate and second plate to form at least one laser weld line, the dead zone being filled by the filler material following melting of this filler material.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawing on the other hand, in which:

FIG. 1 There FIG. 1 is a schematic representation of a sectional view of a heat transfer fluid circulation structure according to the invention;

FIG. 2 There FIG. 2 is a schematic representation of a sectional view of a heat transfer fluid circulation structure according to another exemplary embodiment of the invention;

FIG. 3 There FIG. 3 is a schematic representation of a sectional view of a heat transfer fluid circulation structure according to yet another exemplary embodiment of the invention.

The features, variants and different embodiments of the invention may be combined with each other in various combinations, 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 below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and/or to differentiate the invention from the prior art.

We have represented, on the FIG. 1 , a heat transfer fluid circulation structure 1 for forming a thermal regulation device 100, here a heat exchanger, for cooling and/or heating components whose operation is sensitive to temperature. These components may be battery cells for energy storage. The latter are placed on an external face 101 of the heat transfer fluid circulation structure 1.

The structure 1 is formed of two plates 3 and 5 made of aluminum and welded together to delimit a circulation channel 10 of heat transfer fluid, here glycolated water. Among these plates, a first plate 3 is called a “base plate” (or “base plate” in English) which is flat and a second plate 5 is called a “channel plate” (or “channel plate” in English). In the example of the FIG. 1 , the second plate 5 comprises several rounded grooves 17, longitudinal and parallel, which form several rectilinear and parallel channels 10.

The two plates 3 and 5 are welded by two laser welding lines 4 on either side of the channel 10. At the junctions of the two plates 3 and 5, in a cross-section of the channel 10, said channel 10 has two dead zones 8 with a triangular corner profile. These dead zones 8 are filled with a filling material 20 in particular to reinforce the sealing of the channel 10 with respect to the glycolated water circulating therein. This material 20 is an aluminum-based protective material of type 7072 or 1050. Alternatively, it can also be a covering material (or “cladding” in English), chosen from a covering material of type 4343, 4045, 4047. The filling material 20 undergoes melting during exposure to the heat released during the laser welding and cools following this melting.

This material 20 forms a layer 21 present on the first plate 3, which overflows into the dead zones 8 in the form of a meniscus and extends over the entire width w of the channel 10, between two parallel longitudinal edges. In addition, the filling material 20 runs along the channel 10 over its entire length. The length is the dimension measured along the longitudinal direction of the channels 10.

This meniscus is for example similar to a meniscus obtained during a brazing process and is formed during laser welding. Indeed, the welding laser provides heat and melts the material 20 in order to fill the dead zones 8. The material 20 is then in the form of a meniscus which fills each dead zone 8 of the channel 10. The material 20 here has a thickness of between 5% and 10% of the thickness of the first plate 3.

The material 20 makes it possible to eliminate dead zones 8 which may be areas subject to corrosion problems and/or which may be unwanted air bubble traps.

• déposer sur la première plaque, le matériau 20 sous la forme d’une couche,
• souder par laser la première plaque 3 et la deuxième plaque 5 pour former les lignes de soudure laser 4, les zones mortes 8 sont comblées par fusion du matériau 20.

Structure 1 is thus manufactured in a manufacturing process according to the following steps:

• depositing on the first plate, the material 20 in the form of a layer,
• laser welding the first plate 3 and the second plate 5 to form the laser welding lines 4, the dead zones 8 are filled by melting the material 20.

In another embodiment, not shown, the material 20 is in the form of two distant strips of material 20 which run respectively along the two parallel longitudinal edges of the channel 10.

In another example of embodiment illustrated in the FIG. 2 , the material 20 forming a layer 21 is present mainly on the second plate 5.

In yet another example of embodiment illustrated in the FIG. 3 , the material 20 forms two layers 21 present on both the first plate 3 and the second plate 5. Thus the interior of the channel 10 is entirely covered with material 20.

Claims (10)

Heat transfer fluid circulation structure (1) configured in particular to form a thermal regulation device (100) for cooling and/or heating components whose operation is sensitive to temperature, these components being in particular intended for energy storage and possibly being battery cells, the heat transfer fluid circulation structure (1) comprising at least one heat transfer fluid circulation channel (10) formed between a first plate (3) and a second plate (5) welded together, along at least one laser welding line (4), the channel (10) having at least one dead zone (8) at a junction between the first plate (3) and second plate (5), the dead zone (8) being filled by a filling material (20) distinct from the materials of the first plate (3) and second plate (5). Structure (1) according to claim 1, in which the filling material (20) is part of a layer (21) present on at least one of the first plate (3) and second plate (5). Structure (1) according to claim 2, in which the layer (21) overflows into the dead zone(s) (8) present within the channel (10), at the junction between the first plate (3) and second plate (5). Structure (1) according to one of the preceding claims, in which the filling material (20) is in the form of a strip which runs along the junction between the first plate (3) and second plate (5). Structure (1) according to one of the preceding claims, in which the filling material (20) forms a meniscus, convex or concave, on one side of the channel (10). Structure (1) according to one of the preceding claims, in which the dead zone (8) has, in a cross section of the channel (10), a corner profile formed at the junction of the first and second plates (3, 5). Structure (1) according to one of the preceding claims, in which the filling material (20) has a thickness of between 5% and 10% of the thickness of the plate (3, 5) on which the filling material (20) is present. Structure (1) according to one of the preceding claims, in which the filling material (20) runs along the channel (10) over its entire length. Cooled component system comprising a heat transfer fluid circulation structure (1) according to one of the preceding claims, and at least one component placed on a face (101) of the heat transfer fluid circulation structure (1). Method for manufacturing a heat transfer fluid circulation structure (1) configured in particular to form a thermal regulation device (100) for cooling and/or heating components whose operation is sensitive to temperature, these components being in particular intended for energy storage and possibly being battery cells, the heat transfer fluid circulation structure (1) comprising at least one heat transfer fluid circulation channel (10) formed between a first plate (3) and a second plate (5), the channel (10) having at least one dead zone (8) at a junction between the first plate (3) and second plate (5), the method comprising the following steps:

• depositing on at least one of the first plate (3) and second plate (5), a filling material (20), in particular in the form of a layer (21),
• laser welding the first plate (3) and second plate (5) to form at least one laser welding line (4), the dead zone (8) being filled by the filling material (20) following a melting of this filling material (20).