Thermal management device for an electric battery

Abstract

The present disclosure relates to a thermal management device (200) for an electric battery, the thermal management device comprising a structure (202) made of a compressible material comprising one or more housings (204) arranged in at least one surface of the structure, each housing being filled with an insulator (205), the insulator having thermal insulation properties superior to the thermal insulation properties of the material of the structure.

Description

Description TITLE: Thermal management device for an electric battery technical field

[0001] This disclosure concerns the technical field of electric batteries, and more specifically, the thermal management of said batteries. This disclosure falls within the domain of thermal management elements, particularly for batteries in electric or hybrid vehicles.

[0002] In this respect, the invention relates to a thermal management device for an electric battery. The invention also relates to an electric battery comprising such a thermal management device. Previous technique

[0003] In a multi-cell battery, that is, a battery comprising several independent battery cells grouped in a module, these cells are generally arranged in contact with each other along their sides. During the charging and discharging of the battery cells, heat is produced by the battery cells. In the event of thermal runaway in one cell, it is crucial to limit the spread of heat from one cell to another.

[0004] Under normal use, battery cells expand by several percent in volume. To allow for safe expansion, spacers are placed between the battery cells. These spacers are sufficiently compressible during charge / discharge cycles to allow the expansion of the battery cells without damaging the battery or the spacers themselves. It is common practice to install polyurethane or silicone-based foams between the battery cells to accommodate this expansion under normal use. However, these foams are not suitable for limiting the propagation of thermal runaway because they do not provide sufficient thermal insulation and require excessive thickness to effectively mitigate the effects of thermal runaway. Summary

[0005] This disclosure improves the situation.

[0006] A thermal management device for an electric battery is proposed, the thermal management device comprising a structure made of a compressible material comprising one or more housings fitted in at least one surface of said structure, and in which each housing is filled with an insulator, said insulator having a thermal insulation greater than the thermal insulation of the material of said structure.

[0007] Thus, the thermal management system can deform to allow the expansion of the electric battery elements and helps to limit the spread of heat in the event of thermal runaway thanks to the presence of insulation in the dwellings.

[0008] According to another aspect, it is proposed an electric battery comprising at least two adjacent battery cells and at least one device as above mentioned, said device being interposed between two adjacent battery cells, and / or said battery comprising at least two adjacent battery modules and at least one device as above mentioned, said device being interposed between two adjacent battery modules.

[0009] The features described in the following paragraphs may optionally be implemented, independently of each other or in combination with each other:

[0010] The dwellings can be delimited by walls which serve as reinforcement and mechanical support elements, for example in the shape of a honeycomb.

[0011] The structure's material can be an elastomer, particularly foamed silicone. The material can be chosen to ensure high compressibility of the structure, for example, capable of compressing between 5% and 30% of its thickness.

[0012] The insulation may be a porous material, for example, with a porosity greater than 70%. The insulation may have thermal conductivity properties lower than that of air, less than 30 mW / m / K at ambient temperature. The insulation may be, for example, a compound based on aerogel, fumed silica, or precipitated silica. The insulation may contain at least 50% aerogel. The insulation may advantageously be filled, at least locally, with an opacifying material to improve its thermal insulation properties at higher temperatures.

[0013] The insulation can be a super-insulator such as a compound based on aerogel, fibers, powder, foam or other, in solid, viscous, paste or liquid form.

[0014] Thus, the insulation can cover approximately 70% of the upper surface, while the walls defining the perimeter of the dwellings cover approximately 30% of the upper surface. This distribution of insulation eliminates thermal bridges between the two faces of the thermal management system. It also improves the thermal insulation performance of the system compared to previous construction methods that often present numerous thermal bridges.

[0015] In each dwelling, the insulation can be placed and compacted inside. The dwellings can be filled completely or partially with insulation. The insulation is compressed within the dwellings, which helps to keep it in place, especially when it is in powder form.

[0016] The dwellings may be openings or spaces formed within the structure. The dwellings may open onto one or both faces of the structure. Each dwelling may include a back wall with a thickness between 1% and 10% of the total thickness of the structure.

[0017] At least one of the dwellings may have a depth of between 90% and 99% of the thickness of the structure.

[0018] In particular, at least one of the dwellings can pass through the entire thickness of said structure.

[0019] At least one of the dwellings may have a square, rectangular, polygonal, round, triangular or oval shape.

[0020] The structural and / or insulation material may be flame-retardant or may include a layer of flame-retardant material. The insulation and / or structural material may meet UL94-V0 standards.

[0021] The structure may include at least one pad forming an outgrowth extending from the surface of the structure in the direction of the structure's thickness and away from that surface. The pad may be made of the same material as the structure. The pad may have various shapes.

[0022] At least one of the blocks can be arranged between two successive dwellings.

[0023] The device may include a means for sealing the housings. For example, the sealing means may be a film covering a surface of the structure. In particular, the sealing means may be a polymer and may include an adhesive for bonding to the surface of the structure containing the housings.

[0024] The device may include a solid rim surrounding the surface of the structure containing the housings. The rim may have a width between 0.1 and 50 mm. The housings may be hexagonal in shape and have the same dimensions.

[0025] The device may comprise several superimposed structures. The device may include at least one layer of thermal insulation such as ceramic fibers, felt, or glass wool.

[0026] The structure can comprise at least two groups of housings with different dimensions. Thus, the housings can contain different volumes of insulation. Such an arrangement allows for variation in the thermal conductivity and / or local compressibility of the structure, enabling adaptation to the thermal distribution of the battery cells. Brief description of the drawings

[0027] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: Fig. 1

[0028] [Fig. 1] shows a structure of a thermal management device according to one embodiment. Fig. 2

[0029] [Fig. 2] shows an exploded view of a thermal management device according to one embodiment. Fig. 3

[0030] [Fig. 3] shows a cross-section of the thermal management device in Figure 2.

[0031] [Fig. 4] shows an enlarged area of ​​the thermal management device in Figure 2. Fig. 5

[0032] [Fig. 5] shows an exploded view of the thermal management device according to one embodiment. Fig. 6

[0033] [Fig. 6] shows a structure of a thermal management device according to one embodiment. Fig. 7

[0034] [Fig. 7] shows an enlarged area of ​​the thermal management device including the structure of figure 6. Fig. 8

[0035] [Fig. 8] shows a structure of a thermal management device according to one embodiment. Fig. 9

[0036] [Fig. 9] shows a perspective view of a thermal management device according to one embodiment. Fig. 10

[0037] [Fig. 10] shows a side view of the thermal management device in Figure 9. Fig. 11

[0038] [Fig. 11] shows a perspective view of a thermal management device according to one embodiment. Fig. 12

[0039] [Fig. 12] shows a side view of the thermal management device in Figure 11. Fig. 13

[0040] [Fig. 13] shows an exploded view of part of an electric battery including the thermal management device of figure 2. Fig. 14

[0041] [Fig. 14] shows cross-sectional views of different embodiments of a structure for a thermal management device.

[0042] Description of the implementation methods

[0043] Reference is now made to Figure 1. Structure 100 is configured to be part of a thermal management device that can be placed between two battery cells or two Adjacent battery modules. Structure 100 is square but can be rectangular, oval, circular, or other shapes depending on the application. The dimensions of Structure 100 are adapted to the size of the battery cells or battery modules, particularly in relation to the surface area to be thermally insulated. The thickness of Structure 100 ranges from 0.5 mm to 10 mm.

[0044] In particular, structure 100 is made of elastomer but can be made of any material or combination of materials having compressive properties, especially compressible along the thickness direction of the structure, i.e., perpendicular to the plane in which the structure extends. More specifically, structure 100 can be made of foamed silicone.

[0045] The structure 100 has a rim 102 defining the periphery of the structure and having a thickness e1 corresponding to the thickness of the structure 100. The rim 102 has a width between 0.1 and 50 mm. Of course, the rim 102 can be absent from the structure 100 according to another embodiment, leaving only the surface 106, the structure 100 thus having a thickness e.

[0046] Structure 100 has, on its upper surface (shown in Figure 1), a recess bordered by a rim 102 of thickness e. Several housings 104 are provided on the surface 106 of the recess. These housings 104 form openings or spaces within the structure 100. The housings 104 are hexagonal in shape and all have the same dimensions. Furthermore, the housings 104 are evenly distributed across the surface 106 of the recess in a honeycomb pattern.

[0047] The dwellings 104 do not open onto the surface opposite surface 106, so the structure includes a back wall for each dwelling. Such a back wall can have a thickness of between 1% and 10% of the total thickness of the structure 100. Between the dwellings 104, the structure 100 has walls 108 delimiting each dwelling 104.

[0048] Within each unit, insulation can be placed and compacted inside unit 104. Units 104 can be filled completely or partially with insulation. In particular, the insulation has superior insulating properties compared to structure 100.

[0049] Figure 2 represents an embodiment of a thermal management device 200 comprising a structure 202. The structure 202 includes housings 204 and is similar to the structure 100 of Figure 1. The difference is that the structure 202 lacks the rim 102.

[0050] In addition, insulation 205 is compacted within each housing 204. This insulation 205 can be a super-insulating material such as an aerogel-based compound, fibers, powder, foam, or other material, in solid, viscous, paste, or liquid form. The insulation 205 thus covers approximately 70% of the upper surface, while the walls 207 delimiting the perimeter of the housings cover approximately 30% of the upper surface. This insulation distribution eliminates thermal bridges between the two faces of the thermal management system. This improves the thermal insulation performance of the thermal management system compared to prior art intercalation elements, which exhibit numerous thermal bridges.

[0051] Furthermore, the insulation is compressed within the housings, which helps to keep it contained, especially when it is in powder form. Specifically, the housings 204 are filled with insulation 205 to the top surface of the structure 202 in which the housings are formed. Of course, the housings can be partially filled with insulation. For example, the fill level of a housing can range from 50% to 100% of its volume.

[0052] In addition, the thermal management device 200 includes a silicone base 206 on which the structure 202 is mounted on its lower surface opposite the upper surface. The silicone base 206 improves the stability of the thermal management device 200.

[0053] Alternatively, the 204 dwellings can open onto the lower surface.

[0054] In Figures 3 and 4, the thermal management device 200 is shown without the silicone base 206. To prevent any dispersion of the insulation, the structure 202, which includes the insulation 205, is covered with a film 210 and a film 208 on its upper and lower surfaces, respectively. The films 208 and 210 can be separate or bonded together. For example, the films 208 and 210 can be adhesive and can adhere to the upper and lower surfaces of the structure 202. The films 208 and 210 can be made of polymer and, in particular, of a fire-resistant material.

[0055] Figure 5 represents a thermal management device 300 according to another embodiment.

[0056] Structure 302 comprises the same elements as structure 202. The difference is that structure 302 includes a first group of dwellings 304_1, a second group of dwellings 304_2, and a third group of dwellings 304_3. Dwellings 304_1, 304_2, and 304_3 have the same honeycomb shape but different dimensions. Therefore, dwellings 304_1, 304_2, and 304_3 contain different volumes of insulation 305. The thermal management system 300 includes a film 310 covering the upper surface of structure 302, onto which dwellings 304_1, 304_2, and 304_3 open.

[0057] Such an arrangement allows for local variation of thermal conductivity and / or compressibility, which makes it possible to adapt to the thermal distribution of battery cells.

[0058] With reference to Figures 6 and 7, the thermal management device 400 comprises a structure 402 containing triangular housings 404 distributed regularly on one upper face of the structure 402. Each housing 404 is delimited by walls 407 forming reinforcing ribs of the structure 402. Insulation, similar to insulation 205 or 305, is placed within the housings 404. The housings have a back wall but can extend through the entire thickness of the structure 402.

[0059] Furthermore, the structure includes several pads 406 extending from the upper surface along the thickness direction of structure 402. The pads 406 project outwards from structure 402. Thus, when structure 402 is subjected to compressive stress, the pads 406 are the first to experience this stress and absorb a portion of it by deforming. The pads 406 therefore provide an additional layer of compression.

[0060] Each block 406 is surrounded by dwellings 404, in particular by six dwellings arranged circumferentially around said block 406. Of course, the dwellings 404 may have other shapes and the blocks may be arranged between two or more of these dwellings 404 in a suitable pattern.

[0061] In particular, the 406 studs are cylindrical but can have other shapes, for example a cubic shape.

[0062] The 406 pads are advantageously made of a deformable material, particularly one that can be adjusted according to the thickness of the 402 structure, for example, an elastomer. The 402 structure can be made of elastomer or another material.

[0063] The thermal management system 400 also includes a film 410 covering the upper surface of the structure 402 and a film 408 covering a lower surface of the structure opposite the upper surface. The thermal management system 400 may further include thermal insulation such as ceramic fibers, felt, or glass wool. For example, the thermal insulation may be placed around the studs 406 between the structure 402 and the film 410.

[0064] A thermal management device 500 according to another embodiment is shown in Figure 8. The thermal management device 500 comprises a compressible structure 502 made, for example, of elastomer. The structure 502 includes through-holes 504 through the entire thickness of the square-shaped structure 502 and bordered by walls 507. The through-holes 504 are configured to receive insulation, for example, similar to insulation 205. The structure 502 includes, at the top of each through-hole 504, a reinforcement 506 having a thickness greater than that of the walls 507. The reinforcements 506 have, for example, a hexagonal cross-section in the plane of the structure 502. The reinforcements 506 also have the same thickness as those of the walls 507. The thermal management device 500 may include one or more films surrounding the structure 502.

[0065] With reference to Figures 9 and 10, the thermal management device 600 comprises a compressible structure 602 including several closed housings 604 encapsulating insulation inside the structure 602. The housings 604 are arranged on either side of the structure 602.

[0066] Each dwelling unit has a hexagonal shape comprising an upper wall 604_1 and a lower wall 604_2. The insulation is placed between the upper wall 604_1 and the lower wall 604_2. The upper wall 604_1 and the lower wall 604_2 extend beyond the plane of the upper surface and the plane of the lower surface of the structure 602 on either side.

[0067] The upper wall 604_1 and the lower wall 604_2 can be made in one piece with the structure 602 or can be separated from the structure 602.

[0068] With reference to Figures 11 and 12, the thermal management system 600' comprises the same elements as the thermal management system 600. The difference is that the dwellings 604 are arranged alternately on either side of the structure 602, rather than directly opposite each other. The dwellings 604 located on the upper face of the structure 602 are encapsulated by the wall. upper wall 604_1 and the lower surface of the structure 602. The housings 604 arranged on the lower face of the structure 602 are encapsulated by the lower wall 604_2 and the upper surface of the structure 602. As shown in figure 12, the lower wall 604_2 is arranged between two upper walls 604_1 according to a side view of the structure 602.

[0069] Although the dwellings in the preceding figures are represented with a honeycomb shape, the thermal management device can include dwellings of square, rectangular, polygonal, round, triangular or oval shape.

[0070] The thermal management device according to the previous figures exhibits a low conductivity of less than 30mW / mK with a reduced density.

[0071] Figure 13 shows a battery 1 comprising at least two battery cells 10 and 20 arranged side by side. In order to limit thermal runaway in the battery while allowing the expansion of the battery cells 10 and 20, a thermal management device 200 is interposed between the battery cells. The thermal management device 200 can be replaced by the thermal management device 300, 400, 500, 600, or 600'.

[0072] Battery 1 may include, in addition to the thermal management device, other thermally insulating elements such as silica felts or mineral wool, for example, made of silicate fibers ("Alkaline earth silicate" in English, abbreviated as AES), aluminum, or other films.

[0073] Figure 14a shows a cross-section of a structure 102a similar to structure 100. The difference is that structure 102a includes spaces 104a extending through its thickness. These spaces 104a are bordered by walls 107a. The spaces 104a, containing insulation 105 similar to insulation 205, open onto the lower and upper surfaces of structure 102a. The spaces 104a can be honeycomb, square, rectangular, or any other suitable shape.

[0074] Figure 14b shows a cross-section of a structure 102b similar to structure 102a. The difference is that structure 102b comprises a flexible plate from which walls 107_1 extend from the upper surface of the plate to form spaces 104b_1, and walls 107_2 extend from the upper surface of the plate to form spaces 104b_2. Spaces 104b_1 and 104b_2 contain insulation 105 similar to insulation 205 and open onto the lower and upper surfaces of structure 102a.

[0075] Figure 14c shows a cross-section of a structure 102c similar to structure 102a. In addition, the lower surface of structure 102c is covered by a closure means 108c for the housings 104a, such as a film 108c applied to the surface. The closure means 108c can be a base of structure 102c, like structure 100.

[0076] Figure 14d shows a cross-section of a structure 102d similar to structure 102a. In addition, the lower surface of structure 102d is covered by a closing means 108d for the housings 104a, such as a film applied to the surface or a base of structure 102d. Similarly, the upper surface of structure 102d is covered by a closing means 110d for the housings 104a, such as a film applied to the surface or a base of structure 102d. The means 108d and 110d closures can be an integral part of structure 102c, just like structure 602.

Claims

Demands

1. Thermal management device (200,300,400,500,600,600') for electric battery (1 ) the thermal management device comprising a structure (102,202,302,402,502,602) made of a compressible material comprising one or more housings (104,204,304,404,504,604) arranged in at least one surface of said structure, and in which each housing is filled with an insulator (205), said insulator having a thermal insulation greater than the thermal insulation of the material of said structure, characterized in that the structure comprises at least two groups of housings having different dimensions.

2. Device (200,300,400,500,600,600') according to the preceding claim, wherein the material of the structure is an elastomer.

3. Device (200,300,400,500,600,600') according to any one of the preceding claims, wherein the insulator (205) is a porous material whose thermal conductivity properties are less than that of air, less than 30mW / m / K at room temperature, for example a compound based on aerogel or fumed silica or precipitated silica.

4. Device (200,300,400,600,600') according to any one of the preceding claims, wherein at least one of the housings (104,304,404,604) has a depth between 90% and 99% of the thickness of the structure (102,302,402,602).

5. Device (500) according to any one of claims 1 to 3, wherein at least one of the housings (504) passes through the entire thickness of said structure (502).

6. Device (200,300,400,500,600,600') according to any one of the preceding claims, wherein at least one of the housings (104,304,404,504,604) has a square, rectangular, polygonal, round, triangular or oval shape.

7. Device (200,300,400,500,600,600') according to any one of the preceding claims, wherein the material of said structure (102,302,402,502,602) and / or the insulation (205) is flame retardant or comprises a layer of a flame retardant material.

8. Device (400) according to any one of the preceding claims, wherein the structure (402) comprises at least one stud (406) forming an outgrowth extending from said surface of the structure (402) in the direction of the thickness of the structure and away from said surface of the structure.

9. Device (400) according to claim 8, wherein at least one of the studs (406) is arranged between two successive housings (404).

10. Device (200,300) according to one of the preceding claims, comprising a means for sealing (208,308,210,310) the housings (304,404).

11. Device according to any one of the preceding claims, comprising a solid rim (102) surrounding the surface of the structure (100) comprising the housings (104).

12. Electric battery (1) comprising at least two adjacent battery cells (10,20) and at least one device (200,300,400,500,600,600') according to any one of the preceding claims, said device being interposed between two adjacent battery cells, and / or said battery comprising at least two adjacent battery modules and at least one device according to any one of the preceding claims, said device being interposed between two adjacent battery modules.

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