Cooling device for an electric battery

Abstract

The invention relates to a cooling device for an electric battery, comprising: - a flexible casing (32) made of two sheets (36) of flexible material extending next to each other, the casing (32) having weld regions (38) in which the sheets (36) are secured to each other and separation regions (40) in which the sheets (36) can extend away from each other, - at least one fluid circulation channel (52) extending between the sheets (36) through at least one of the separation regions (40), characterized in that the cooling device (30) further comprises: - a support structure fastened to the casing (32), the support structure comprising a semi-rigid plate (54) in contact with the casing (32) in a fastening direction, the semi-rigid plate (54) extending perpendicularly in relation to the fastening direction, the semi-rigid plate (54) being capable of deforming in compression in the fastening direction in order to compensate for a deformation of the casing (32) under the effect of an internal fluid-circulation pressure in the at least one channel (52).

Description

[0001] DESCRIPTION

[0002] TITLE: Cooling device for an electric battery

[0003] Technical field of the invention

[0004] The invention relates to the technical field of electric batteries, and more specifically to the cooling of said batteries. These batteries are, for example, installed on an electric or hybrid vehicle.

[0005] In this respect, the invention relates to a cooling device for an electric battery. The invention also relates to an electric battery comprising such a cooling device.

[0006] Prior art

[0007] In a multi-cell battery, that is, a battery comprising several independent battery cells grouped within a casing, the hottest cells are located in the center. Since the cells are generally arranged side-to-side to reduce overall size, the heat generated by these most enclosed cells is dissipated only through their undersides. The electrical connectors between these different battery cells are usually located on the top surfaces and are also likely to generate significant heat.

[0008] Indirect fluid cooling is the most common method used by manufacturers because it is efficient, relatively simple to implement, and inexpensive. This method involves circulating a cooling fluid (usually a water-glycol mixture) through a cooling unit located above or below the battery cells. The fluid acts as a heat transfer fluid, removing thermal heat from the battery and discharging it outside the enclosure as it circulates.

[0009] Therefore, heat dissipation is highly dependent on the thermal resistance of exchange between the electrical connectors or the underside of the battery elements as appropriate, on the one hand, and the cooling device on the other.

[0010] To improve this thermal exchange resistance, it is known to use thermal interface materials, such as thermally conductive resins, between the cold plate of the cooling device and the underside surfaces of the battery cells or the complex structures of the connectors. This bridges the local gaps between these surfaces caused by the asperities and roughness of these solid structures. However, such a solution significantly increases the cost and mass of the battery. Furthermore, the thermal contact achieved through the use of such an interface material remains considerably less efficient than direct mechanical contact between conductive metallic materials, for example.

[0011] Another possibility for improving thermal contact is the use of a flexible envelope for the circulation of the heat transfer fluid instead of a rigid structure, the said flexible envelope deforming freely under the effect of the circulation pressure of the heat transfer fluid and thus conforming to the contours of the lower surface of the battery elements or electrical connectors, thereby providing good thermal contact.

[0012] The flexible casing is designed using two multi-material, multi-layered film sheets joined by local welding to form one or more fluid circulation channels. The two sheets can be separate or formed from a single sheet folded over itself.

[0013] Such an envelope thus allows for a cooling device that benefits from good thermal contact with the battery elements to be cooled, while being lightweight and simple to manufacture compared to previous rigid coolers.

[0014] To facilitate handling and securing such a flexible casing, it is known, for example from patent application FR 2311874, to attach the flexible casing to a support frame, made, for example, of rigid molded plastic. Such a frame also allows for counter-pressure to be applied to the parts of the casing not in contact with a rigid element, thus preventing the casing from deforming and wearing under the effect of the internal fluid flow pressure.

[0015] However, such a cooling system can still be improved. Indeed, the circulating pressure of the cooling fluid can exert a significant force on the components surrounding the pocket, particularly certain parts of the battery elements or even the walls of the enclosure containing the battery and the cooling system, and deform or even damage them in the long term.

[0016] Presentation of the invention

[0017] The invention aims to remedy these drawbacks by proposing a cooling device for an electric battery, implementing a flexible casing as described above and allowing a reduction in wear of surrounding elements by the pressure of fluid circulation in the casing.

[0018] To this end, the invention relates to a cooling device for an electric battery, the cooling device comprising:

[0019] - a flexible envelope formed of two sheets of flexible material extending opposite each other, the envelope having welded regions in which the sheets are joined together and separation regions in which the sheets are able to extend apart from each other,

[0020] - at least one fluid circulation conduit extending between the sheets through at least one of the separation regions, characterized in that the cooling device further comprises:

[0021] - a support structure fixed to the casing, the support structure comprising a semi-rigid plate in contact with the casing along a direction of attachment, said semi-rigid plate extending perpendicularly to the direction of attachment, the semi-rigid plate being capable of deforming in compression along the direction of attachment to compensate for deformation of the casing under the effect of internal pressure of fluid circulation in at least one conduit.

[0022] This cooling system ensures satisfactory mechanical strength of the assembly, composed of the semi-rigid plate and the flexible sleeve, for handling and securing. Furthermore, the semi-rigid plate is designed to deform when the circulating pressure of the coolant in the flexible sleeve increases. This allows for compensation of these deformations on the side opposite the battery cells, thus reducing the stress exerted on these battery cells by said circulating pressure.

[0023] The support structure may include fastening elements, attached to the semi-rigid plate by snap-fit ​​and adapted to fix the support structure to a battery enclosure.

[0024] This feature simplifies the attachment of the support structure to the drum enclosure without modifying the semi-rigid plate.

[0025] The fastening devices can also be adapted to fix the casing to the semi-rigid plate by snapping it into place.

[0026] This feature allows the same fasteners to be used to perform several functions simultaneously.

[0027] The semi-rigid plate can be attached to the casing by at least one adhesive area.

[0028] Such a feature allows an additional or alternative means of fixing the plate to the casing, so as to guarantee the maintenance of a large contact surface between them.

[0029] The semi-rigid plate may comprise at least one polymer material, in particular at least one polymer material in a multilayer structure.

[0030] Such a characteristic makes it possible to optimize the mechanical properties of the semi-rigid plate for its role of absorbing the stresses resulting from the circulation pressure in the pocket, and in addition to adding additional functions to the plate by adding corresponding additional layers.

[0031] The semi-rigid plate may include a foam made of polymer material. This feature allows the semi-rigid plate to have interesting mechanical properties, notably good elastic compressibility in the direction perpendicular to the plate.

[0032] The semi-rigid plate may include at least one fire-retardant layer and / or at least one fire-retardant layer,

[0033] Such a feature makes it possible to prevent the occurrence of a fire within the enclosure in the event of thermal runaway, and / or to reduce its consequences.

[0034] The semi-rigid plate can exhibit a deformation rate of 50% in compression along the direction of attachment for a compressive stress between 1 kPa and 250 kPa, in particular between 30 kPa and 200 kPa and advantageously between 60 kPa and 150 kPa.

[0035] Such a characteristic allows the compression deformation rate of the semi-rigid plate, under the effect of usual circulation pressures of the flexible pouch, to be less than 90%, in particular less than 80%, and for example less than 70%, which makes it possible to compensate for the associated stresses while remaining in an elastic regime without damage.

[0036] These compressive stress values ​​leading to a strain rate of 50% in compression are measured for example according to the NFR 99211 standard or the ASTM D1056 standard.

[0037] The semi-rigid plate may have dimensions, measured perpendicular to the direction of attachment, greater than or equal to corresponding dimensions of the envelope, measured perpendicular to the direction of attachment, so that the semi-rigid plate extends beyond the lateral edges of the envelope, perpendicular to the direction of attachment.

[0038] This feature allows for a contact surface between the casing and the plate that covers an entire surface of the casing, on the side opposite the battery elements, in order to exert counter-pressure on the entire casing.

[0039] The invention also relates to an electric battery comprising:

[0040] - a plurality of battery cells arranged in an enclosure, each battery cell having cooling elements arranged on an upper, lower, or lateral face of the battery cell, and

[0041] - a cooling device as above, the flexible casing being arranged to come into contact with the elements to be cooled when a cooling fluid circulates through at least one circulation channel, the support structure being arranged against the casing, on the side of the casing opposite the elements to be cooled. Brief description of the figures

[0042] [Fig. 1 A] is a schematic cross-sectional view of a battery comprising a cooling device according to the invention,

[0043] [Fig. 1 B] is a schematic cross-sectional view of a battery comprising a cooling device according to another embodiment of the invention,

[0044] [Fig. 2] is a perspective view of a flexible casing of the cooling device in Figure 1A,

[0045] [Fig. 3] is a perspective view of a support structure for the cooling device in Figure 1A,

[0046] [Fig. 4] is a cross-sectional view of the envelope and support structure of Figures 2 and 3, and

[0047] [Fig. 5] is a perspective view of a fixing member of the cooling device of Figure 1A.

[0048] Detailed description of the invention

[0049] Figure 1A represents an electric battery 10 intended for energy storage, intended in particular for applications on board a vehicle, for example an electric or hybrid powered vehicle.

[0050] The said vehicle is, for example, a motor vehicle, a road or rail transport vehicle, a maritime vehicle, or other.

[0051] Alternatively, battery 10 is intended for a fixed or mobile installation requiring an electrical power supply, without connection to the power grid, or as a supplement to it.

[0052] The battery comprises a closed enclosure 12, substantially sealed, and a plurality of battery elements 14, or cells, arranged in the enclosure 12 and suitable for storing electrical energy.

[0053] The enclosure 12 includes a removable upper cover 15, which defines passageways for supplying the cooling fluid. According to the embodiment shown in Figure 1A, connectors 16 for circulating said cooling fluid are arranged opposite the passageways in the cover 15, so as to supply the cooling fluid from the top of the enclosure 12.

[0054] Alternatively, as shown in the embodiment of Figure 1B, the fluid connectors 16 are not positioned facing the cover 15, and the cooling fluid is supplied through another face of the enclosure 12 (not shown). In this case, the cover 15 may not have any openings.

[0055] Each battery element 14 has a general shape that is substantially parallelepiped-shaped and thus defines an upper face 18, a lower face 20 and four lateral faces.

[0056] The terms "upper" and "lower" are understood here in relation to a standard positioning of the battery under operating conditions.

[0057] The battery elements 14 are arranged aligned in at least one row extending along an alignment direction X. An elevation direction Z and a transverse direction Y are further defined, both perpendicular to each other and perpendicular to the alignment direction X, the elevation direction Z being substantially vertically oriented in a standard operating orientation of the battery 10.

[0058] The battery elements 14 can be arranged in contact with each other by their respective lateral faces, along the alignment direction X, or with small gaps between two neighboring battery elements along the alignment direction X.

[0059] Each battery element 14 has connectors (not shown) arranged on its upper face 18, on either side of said upper face along the transverse direction Y. The connectors of the battery elements thus form two rows extending along the alignment direction X.

[0060] The connectors of the battery elements 14 are connected to parallel bus bars 24 which extend substantially along the alignment direction X, allowing energy to be supplied to the battery elements 14 for storage or energy to be withdrawn from the battery elements to power an electrical device.

[0061] Battery 10, and more specifically battery elements 14, generate heat during operation and require cooling for optimal operation and to have a satisfactory operating time and safety.

[0062] For this purpose, the battery 10 includes at least one cooling device 30 for the battery elements to be cooled, shown in more detail in figures 2 to 4.

[0063] The elements to be cooled may be the battery cells 14, and more specifically the lower faces 20 or lateral faces of the battery cells, or the connectors of the battery cells as well as the bus bars 24, which are arranged above the upper faces of the battery cells.

[0064] In the example shown in the figures, the cooling device 30 is arranged to cool the connectors of the battery elements 14 and the bus bars 24, and is thus positioned in the enclosure 12, suspended from the cover, above the battery elements 14.

[0065] The cooling device 30 includes a flexible casing 32 for holding the cooling fluid, at least one inlet fluid connector 16 and at least one outlet fluid connector 16 (shown in Figures 1A and 1B) mounted on the casing 32, and a support structure 34 adapted to support the casing 32 and improve its rigidity for handling.

[0066] The fluidic connectors 16 are for example of the type described in application FR 2311874. In the battery, the casing 32 and the support structure 34 are assembled to each other along a fixing direction, which is parallel to the elevation direction Z in the example shown.

[0067] According to some embodiments, the fluidic connectors 16 are located on the casing 32 opposite the cover 15 (Figure 1A) or on the opposite side of the cover 15 (Figure 1B).

[0068] The enclosure 32 is arranged in contact with the elements to be cooled, i.e. with the battery elements 14 and / or with the electrical connectors of these elements and / or with the bus bars, on the side opposite the support structure 34.

[0069] Thus, in battery 10, the battery elements 14, the flexible pouch 32 and the support structure 34 are aligned in this order according to the assembly direction.

[0070] Thus, the support structure 34 is located on the opposite side of the casing 32 to the battery elements 14, and vice versa.

[0071] The envelope 32, shown in detail in figure 2, is formed of two sheets 36 of flexible material extending opposite each other and partially welded to each other.

[0072] Thus, the envelope 32 has welding regions 38, in which the sheets 36 are joined together, and separation regions 40, in which the sheets 36 are not welded together and are thus able to extend the gap between them, defining an internal space between them.

[0073] The weld regions 38 follow in particular an external contour of the envelope 32, so as to make an internal space of the envelope 32 watertight.

[0074] In the example shown, the flexible envelope 32 has a substantially flattened rectangular shape, designed to extend substantially perpendicular to the Z elevation direction once placed in the housing.

[0075] The outer contour of the envelope 32 defines lateral edges 42, in particular external lateral edges 42 extending along the long sides and short sides of the rectangular shape of the envelope.

[0076] The rectangular shape of the envelope 32 includes, for example, two such large sides, which extend along the alignment direction X, and two small sides, which extend along the transverse direction Y.

[0077] The enclosure 32 thus comprises a front face, intended to be in contact with the elements to be cooled, for example, battery cells, and a rear face, extending opposite the front face, facing the support structure 34, and advantageously in at least partial contact with said support structure. The enclosure 32 may define at least one elongated central opening 44, for example, three central openings 44 as shown, which allow passage of elongated portions of the battery cells 14, such as sensor or battery control connectors.

[0078] The 36 sheets are formed from a multilayer film cut to obtain the desired geometry.

[0079] The film, for example, is a stack of layers such as: a first layer of polyethylene terephthalate (PET), a layer of aluminum (Al), a second layer of polyethylene terephthalate, and a layer of polyethylene (PE). This type of film is commonly used in the food industry for effective product insulation.

[0080] In the case of the flexible envelope 32, the aluminum layer provides very good thermal conductivity and reduces the risks of fluid permeation through the sheets, the polyethylene terephthalate layers provide good resistance to temperature and ambient environment, and the polyethylene layer serves as an adhesive layer, for fixing the two sheets by melting the two polyethylene layers in contact with each other.

[0081] The envelope 32 further includes at least two ports 46 arranged to receive at least one inlet fluidic connector 16 and at least one outlet fluidic connector 16.

[0082] The envelope 32 includes at least one fluid circulation conduit 52, shown in Figure 2, extending between the sheets 36 of the envelope from the orifice 46 receiving at least one inlet connector to the orifice 46 receiving at least one outlet connector.

[0083] The separation regions 40 of the sheets 36 together define said at least one fluid circulation conduit 52 in the internal space.

[0084] In the example shown, the ports 46 receiving the inlet and outlet fluidic connectors are positioned at the same side of the rectangular shape of the envelope 32. For example, the ports 46 receiving the two fluidic connectors are positioned on the same short side of the rectangular shape of the envelope 32, that is to say at the same end of the envelope 32 along the alignment direction X, and on either side of said rectangular shape along the transverse direction Y.

[0085] In the example shown, the enclosure 32 includes a single fluid circulation conduit 52 having a W shape, that is to say the conduit 52 extends from the orifice 46 receiving the inlet connector along one of the long sides, then along the short side opposite the connectors, then along the central openings 44, then along the short side near the connectors, then again along the openings 44, again along the short side opposite the connectors, and finally along the other of the long sides to the orifice 46 receiving the outlet connector.

[0086] More generally, the conduit 52 preferentially extends along a path forming at least one round trip on the envelope 32, in order to allow the fluidic connection of the inlet and outlet at the level of the same lateral edge 42 of the envelope 32, which facilitates the supply and departure of the cooling fluid.

[0087] The conduit 52 can also extend along a meandering path over the extent of the envelope 32, i.e. forming at least one meander, which makes it possible to increase the cooled surface area.

[0088] Thus, conduit 52 can have a shape in II, V, W, S, etc...

[0089] Alternatively, the envelope 32 may comprise several conduits 52 extending divergently from at least one entry point and regrouping at at least one exit point.

[0090] Alternatively, the envelope 32 may comprise a plurality of conduits 52 fluidically separated from each other.

[0091] In particular, the enclosure 32 may include two substantially straight and parallel conduits 52 extending along the two rows of connectors and bars 24, according to the alignment direction X.

[0092] Advantageously, the circulation duct(s) 52 extend away from the lateral edges 42 of the casing, so as to leave a rim 48 extending around the outer perimeter of the casing. This improves the sealing of the casing and provides a useful surface for fixing the casing at its outer edges.

[0093] Advantageously, the envelope 32 may include fastening holes 53, extending over both sheets, for example substantially circular. The fastening holes 53 are, for example, arranged along the lateral edges 42, particularly in the rim 48, and / or in a central region of the envelope 32.

[0094] According to the invention, the cooling device 30 further comprises a support structure 34 for the flexible casing 32, comprising a semi-rigid plate 54 shown in detail in Figure 3.

[0095] The terms "rigid," "semi-rigid," and "flexible" are used here in a relative sense. Specifically, the term "rigid" refers to materials with low deformation resistance used for state-of-the-art support structures. For example, such rigid materials undergo only negligible deformation when exposed to standard cooling fluid pressures within the casing. Examples of such rigid structures include most massive metal or plastic structures with a significant thickness, for example, 1 mm or more for metals and 5 mm or more for plastics.

[0096] Conversely, flexible structures such as the casing deform easily under exposure to standard cooling fluid circulation pressures within the casing.

[0097] Furthermore, the flexible nature of the envelope 32 implies that without external action, the envelope deforms under the effect of its own weight, while the rigid nature of the support structure 34 implies that it does not undergo significant deformation under the effect of its own weight.

[0098] Examples of flexible materials include, for example, the films described above.

[0099] The semi-rigid nature of the support plate for the cooling device according to the invention corresponds to an intermediate situation between a flexible structure and a rigid structure as described above. This means that the semi-rigid plate exhibits a stiffness, particularly a flexural stiffness, that is significantly greater than the stiffness of a flexible casing and significantly less than the stiffness of a rigid structure.

[0100] Specifically, the semi-rigid plate is elastically deformable, meaning it can reversibly deform in compression, for example, under the stresses associated with standard coolant circulation pressure. However, this semi-rigid plate does not deform significantly under its own weight or the weight of the flexible casing (when empty, i.e., without considering the weight of any coolant that might be contained within the casing), which allows it to play a structural role in the support structure of the flexible casing.

[0101] The semi-rigid plate 54 extends, for example, substantially perpendicular to the assembly direction and has, for example, a generally rectangular shape. In particular, the plate 54 has four lateral edges 56, a front face 60, and a rear face 58.

[0102] Plate 54 has a thickness, measured along the direction of fixation between the anterior face 60 and the posterior face 58, which is substantially constant over the extent of plate 54.

[0103] The thickness of plate 54, for example, is between 5 mm and 50 mm, and varies depending on the material or materials composing plate 54.

[0104] The dimensions of the plate 54, for example a length and a width of the plate, are advantageously greater than or equal to the corresponding dimensions of the envelope, so that the plate 54 can extend against the whole of the rear face of the envelope 32 when they are fixed to each other, and advantageously beyond the envelope 32.

[0105] In particular, the posterior face of the casing 32 is at least partially in contact with the anterior face 60 of the plate 54, and for example, in contact over at least 70% of the surface of the posterior face of the casing 32, in particular at least 80% and preferably at least 90%. The casing 32 and the plate 54 are in contact with each other along the direction of fixation. Advantageously, the plate 54 defines at least one substantially central elongated opening 62, the opening(s) 62 corresponding to the central opening(s) 44 of the casing 32, along the direction of fixation.

[0106] Advantageously, the plate 54 defines fixing holes 64 aligned with the fixing holes 53 of the casing 32 along the fixing direction. The fixing holes 64 are, for example, substantially circular and pass through the plate 54 from the front face to the back face.

[0107] The fixing holes 64 are for example arranged along the lateral edges of the plate 54 and / or at a central region of the plate 54.

[0108] Plate 54 comprises, for example, at least one polymer material, and advantageously several polymer materials arranged in a multilayer structure. Such a multilayer structure comprises a plurality of layers made of materials that differ in nature or structure. For example, these different materials may include polymers with different chemical formulas and / or different molecular arrangements. The materials constituting the layers of plate 54 may also have different mechanical structures, for example, the same polymer forming one solid layer and one foam layer.

[0109] The term "foam" refers to a material comprising a solid phase, for example, a polymer, and significant porosity containing, for example, air. The porosity typically occupies between 20% and 80% of the total volume of the porous material. The porosity may be open or closed.

[0110] Such a layer of foam allows the plate 54 to have significant compressibility, depending on the direction of attachment.

[0111] Advantageously, at least one of the layers of plate 54 comprises such a polymer foam.

[0112] These layers extend substantially parallel to each other and substantially perpendicular to the direction of assembly.

[0113] These layers may have different thicknesses, measured according to the direction of attachment.

[0114] According to one embodiment, plate 54 consists of a single layer of polymer foam.

[0115] The polymer material(s) constituting one or more layers of plate 54 may, for example, be chosen from polyurethane (PU), polyvinyl chloride (PVC), polystyrene (PS), silicone, synthetic rubbers such as ethylene propylene diene monomer (EPDM), acrylonitrile butadiene styrene (ABS), high-density polyethylene (HDPE), ultra-high-molecular-weight polyethylene (UHDPE), polypropylene (PP), polytetrafluoroethylene (PTFE), ethylene vinyl acetate (EVA), polyethersulfone (PES), polypropylene / polyethylene copolymers (PP / PE), polyethylene terephthalate (PET), derivatives of cellulose, latex or cork and thermoplastic elastomers (TPE), such as thermoplastic olefins (TPO), styrenic thermoplastics (TPS), vulcanized thermoplastics (TPV), copolymers thermoplastics (TPC) or thermoplastic polyurethanes (TPU).According to one embodiment, the plate 54 comprises at least one layer including at least one additive added to the material forming the layer and rendering the layer flame-retardant and / or fire-retardant. This flame-retardant and / or fire-retardant layer forms, for example, the front face 60 of the plate 54.

[0116] Examples of such additives include inorganic hydroxides, for example aluminium hydroxide (Al(OH)3) or magnesium hydroxide (Mg(OH)2), halogenated compounds, such as tetrabromobisphenol A (TBBPA) or hexabromocyclododecane (HBCD), halogen-metal synergistic systems, such as antimony halides (Sb2O3), organic or inorganic phosphorus compounds, such as ammonium phosphate, systems with intumescent behavior, or nanocomposites, such as layered silicate systems.

[0117] As shown in Figure 4, the semi-rigid plate 54 is capable of deforming in compression along the fixing direction Z to compensate for the deformations of the envelope 32 under the effect of an internal circulation pressure of the fluid flow F.

[0118] By "compensating for deformations of the casing," we mean that the expansion of the casing 32 under the effect of the circulating coolant pressure results in a compression of the plate 54 along the direction of attachment of equal magnitude. Thus, the casing 32 does not exert excessive mechanical stresses on the components to be cooled on the side opposite the plate.

[0119] As can be seen in Figure 4, the deformations of the plate 54 are located in regions 66 of the plate 54 in contact with the separation regions 40 forming the coolant circulation channels.

[0120] Advantageously, plate 54 has a compression strain rate, according to the direction of attachment, of 50%, for a compressive stress between 1 kPa and 250 kPa, in particular between 30 kPa and 200 kPa and advantageously between 60 kPa and 150 kPa.

[0121] These mechanical deformation rates in compression are measured, for example, according to the NFR 99211 standard or the ASTM D1056 standard.

[0122] Such deformation rate values ​​correspond, for example, for the semi-rigid plate 54, to a compressive stiffness modulus between 2 kPa and 500 kPa, in particular between 60 kPa and 400 kPa and advantageously between 120 kPa and 300 kPa.

[0123] The said stiffness module is determined according to the direction of attachment, i.e. perpendicular to the main extension plane of plate 54.

[0124] Such stiffness or compression strain rate values ​​allow the plate 54 to compensate for deformations of the casing due to the circulating pressure of the cooling fluid, while maintaining a sufficiently low strain rate for the plate 54 to deform elastically. This elastic deformation prevents wear and damage to the plate 54 during repeated and / or prolonged use. For example, the stiffness of the plate 54 along the direction of attachment is determined so that the compression strain rate of the plate 54, under the effect of typical circulating pressures of the flexible casing, is less than 90%, in particular less than 80%, and for example less than 70%, thus compensating for the associated stresses while remaining in an elastic regime without damaging the plate 54.

[0125] In the case of a multilayer plate 54, this is then an overall stiffness, that is to say a resistance to an overall deformation of the plate 54, according to the direction of fixing, under the effect of compressive stresses.

[0126] Advantageously, the support structure 34 further includes fastening elements 70 adapted for fixing the support structure 34 to the cover of the enclosure 12 of the electric battery.

[0127] The fastening members 70 are for example of the type shown in Figure 5, comprising a base 72 and a ratcheting member 74 fixed to the base, as well as a fixing ring 76 movable relative to the base 72 and adapted to cooperate with the ratcheting member 74.

[0128] The base 72 is for example substantially cylindrical and defines a flat surface 77 in contact with the envelope 32 or the plate 54, the snap-fit ​​member 74 protruding from the flat surface, for example in the middle of it.

[0129] The snap-on member 74 includes, for example, one or more elastic arms 79 projecting from the base 72, having at their free end teeth 80 adapted to lock the ring 76.

[0130] The snap-fit ​​members 74 of the fasteners 70 are for example engaged in the fastener holes 53 of the casing 32 and in the fastener holes 64 of the plate 54, along the outer edges and engaged above in the corresponding fastener rings 76.

[0131] Ring 76, for example, is substantially annular and designed to bear against plate 54 or envelope 32, on the side opposite base 72.

[0132] Thus, the fastening elements 70 contribute to the fixing of the envelope 32 onto the plate 54.

[0133] The fixing devices 70 of the support structure 34 may also include hooks and / or rings 78 attached to the base 72, suitable for fixing the support structure 34 to the enclosure 12, for example to the cover 15 or to a side or bottom wall of the enclosure 12.

[0134] Advantageously, the casing 32 and / or the plate 54 include adhesive regions on their respective contact faces, i.e. on the posterior face of the casing and / or on the anterior face of the plate 54. These adhesive regions ensure the attachment of the casing 32 to the plate 54, or supplement the attachment provided by the fixing elements 70. The adhesive regions may extend over the entire contact surface between the casing 32 and the plate 54, i.e. over the entire posterior face of the casing 32 with the exception of the openings 44, 62 of the casing 32 and the plate 54.

[0135] Alternatively, only the plate 54 defines fixing holes 64, the envelope 32 not defining fixing holes 53. The fixing members 70 are fixed only to the plate 54, the fixing of the envelope 32 to the plate 54 being ensured only by the adhesive regions.

Claims

DEMANDS 1. Cooling device (30) for an electric battery (10), the cooling device (30) comprising: - a flexible envelope (32) formed of two sheets (36) of flexible material extending opposite each other, the envelope (32) having weld regions (38) in which the sheets (36) are joined together and separation regions (40) in which the sheets (36) are able to extend apart from each other, - at least one fluid circulation conduit (52) extending between the sheets (36) through at least one of the separation regions (40), characterized in that the cooling device (30) further comprises: - a support structure fixed to the casing (32), the support structure comprising a semi-rigid plate (54) in contact with the casing (32) along a direction of attachment, said semi-rigid plate (54) extending perpendicularly to the direction of attachment, the semi-rigid plate (54) being capable of deforming in compression along the direction of attachment to compensate for a deformation of the casing (32) under the effect of an internal pressure of fluid circulation in at least one conduit (52).

2. Cooling device (30) according to claim 1, in which the support structure (34) includes fastening members (70), fixed to the semi-rigid plate (54) by snap-fitting and adapted to fix the support structure (34) to a battery enclosure (12).

3. Cooling device (30) according to claim 2, wherein the fastening members (70) are further adapted to fix the casing (32) to the semi-rigid plate (54) by snapping.

4. Cooling device (30) according to any one of claims 1 to 3, wherein the semi-rigid plate (54) is fixed to the casing (32) by at least one adhesive region.

5. Cooling device (30) according to any one of claims 1 to 4, wherein the semi-rigid plate (54) comprises at least one polymer material, in particular at least one polymer material in a multilayer structure.

6. Cooling device (30) according to any one of claims 1 to 5, wherein the semi-rigid plate (54) comprises a foam made of polymer material.

7. Cooling device (30) according to any one of claims 1 to 6, wherein the semi-rigid plate (54) comprises at least one fire-retardant layer and / or at least one fire-retardant layer, 8. Cooling device (30) according to any one of claims 1 to 7, wherein the semi-rigid plate (54) has a deformation rate of 50% in compression along the direction of attachment for a compressive stress between 1 kPa and 250 kPa, in particular between 30 kPa and 200 kPa and advantageously between 60 kPa and 150 kPa.

9. Cooling device (30) according to any one of claims 1 to 8, wherein the semi-rigid plate (54) has dimensions, measured perpendicular to the direction of attachment, greater than or equal to corresponding dimensions of the casing (32), measured perpendicular to the direction of attachment, such that the semi-rigid plate (54) extends beyond lateral edges of the casing (32), perpendicular to the direction of attachment.

10. Electric battery (10) comprising: - a plurality of battery cells (14) arranged in an enclosure (12), each battery cell (14) having cooling elements arranged on an upper, lower, or lateral face of the battery cell (14), and - a cooling device (30) according to any one of the preceding claims, the flexible casing (32) being arranged to come into contact with the elements to be cooled when a cooling fluid circulates in at least one circulation conduit (54), the support structure (34) being arranged against the casing (32), on the side of the casing (32) opposite the elements to be cooled.

Images