AT527873B1 - Heat transfer device - Google Patents

Abstract

The invention relates to a heat transfer device (4) comprising an element body having at least one fluid channel (9), wherein the fluid channel (9) is formed at least partially by a first heat transfer element (6) made of a first composite material having, one above the other in the specified order, a first plastic layer (13), a first conductive layer (14), a second plastic layer (15), and a second conductive layer (16), wherein the first and second conductive layers (14, 16) have an electrical conductivity at 25°C according to DIN EN 50994:2017-11 of at least 1 S/m and/or a thermal conductivity at 25°C according to ASTM E1530 of at least 0.1 W/mK. The first and second conductive layers (14, 16) are a metal layer or a metal-deposited polymer layer or a polymer layer made of a conductive polymer.

Description

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Description

[0001] The invention relates to a heat transfer device comprising an element body which has at least one fluid channel, wherein the fluid channel is at least partially formed by a first heat transfer element, wherein the first heat transfer element is formed from a first composite material which has a first plastic layer, a first conductive layer and a second plastic layer one above the other in the specified order, wherein the first conductive layer has an electrical conductivity at 25 °C according to DIN EN 50994:2017-11 of at least 1 S/m and/or a thermal conductivity at 25 °C according to ASTM E1530 of at least 0.1 W/mK and wherein the first conductive layer is a metal layer or a metal-deposited polymer layer or a polymer layer made of a conductive polymer.

[0002] Furthermore, the invention relates to an accumulator with at least one storage element for storing electrical energy and at least one heat transfer device for cooling or tempering the storage element.

[0003] The use of multilayer films in accumulator coolers is already known from the prior art. For example, WO 03/071616 A2 describes an electrochemical storage unit with multiple electrochemical cells and a cooling bladder formed from a deformable, thermally conductive material, having an inlet port and an outlet port, and through which a heat transfer medium flows. The material used in the manufacture of the cooling bladder can be a multilayer material. A three-layer construction is described in which a metal layer is arranged between a first polymer layer and a second polymer layer. For example, a thin metal foil, such as aluminum foil, can be used to minimize water vapor permeability over the lifetime of the cooling bladder. A heat-sealable film, such as a polyethylene film, is applied to a first side of the metal foil. A protective film, such as a nylon or polypropylene film, is applied to a second side of the metal foil.

[0004] AT 520 018 A1 discloses an accumulator with at least one cell for storing electrical energy and at least one cooling device for cooling or tempering the cell. The cooling device comprises at least one multilayer film for forming a coolant channel. The film consists of a laminate comprising a first plastic film, a reinforcement layer connected thereto, a metal foil connected to the reinforcement layer, or a metallized further plastic film connected to the reinforcement layer.

[0005] CN 116960533 A discloses a flame-retardant aluminum-plastic film with high thermal conductivity, comprising, from the inside out, a polyolefin film layer, a first adhesive layer, a first passivation layer, an aluminum foil layer, a second passivation layer, a second adhesive layer, and an insulating film layer. The polyolefin film layer consists of a heat-sealing layer, a carrier layer, a thermally conductive layer, and a lamination layer. The insulating film layer is a coextruded film layer comprising several nylon layers and a glass fiber-reinforced modified polyethylene terephthalate layer.

[0006] EP 4 199 191 A1 describes a battery module comprising a battery cell stack comprising a plurality of battery cells stacked in a first direction, a first heat sink located at a lower part of the battery cell stack, a first thermally conductive resin layer located between the battery cell stack and the first heat sink, and an outer member surrounding the outer surface of the battery cell stack, wherein the battery cell stack comprises at least one cooling fin arranged between adjacent battery cells of the plurality of battery cells, and wherein the first thermally conductive resin layer and the first heat sink are located between the outer member and a bottom side of the battery cell stack.

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[0007] US 2022/399622 A1 discloses a battery module comprising a battery cell stack comprising a plurality of battery cells, a housing comprising the battery cell stack, and an insulating element arranged between the battery cell stack and the housing, wherein the insulating element is formed continuously on a bottom side and two side surfaces of the battery cell stack.

[0008] EP 4 024 568 A1 describes a battery pack comprising a battery cell stack formed by stacking a plurality of battery cells, an adhesive layer applied to a bottom surface of the battery cell stack, a lower pack case having a plurality of module regions and on which the battery cell stack is mounted, and a thermally conductive resin layer located between the adhesive layer and the lower pack case, the adhesive layer having an insulating property.

[0009] From EP 3 975 319 A1 a battery module is known, comprising a battery cell stack in which a plurality of battery cells are stacked, a module frame for receiving the battery cell stack, a heat-conducting resin layer located between a lower part of the module frame and the battery cell stack, and a heat sink below the lower part of the module frame, wherein the lower part of the module frame forms an upper plate of the heat sink, and wherein a portion with exposed ends of the bottom portion of the module frame is formed at one end of the heat sink.

[0010] US 2014/338879 A1 describes a heat transfer device comprising a composite material consisting of a metal layer, a dielectric layer located on the metal layer, and one or more electrically conductive layers located on the dielectric layer on a side opposite the metal layer.

[0011] US 2013/126146 A1 describes a planar heat dissipation pad comprising a polymer substrate, an adhesive layer disposed beneath the polymer substrate for attaching the heat dissipation pad to a surface of an electronic device, a protective film for covering the adhesive layer, wherein the protective film is removed from the adhesive layer prior to applying the planar heat dissipation patch, and a heat dissipation layer formed on the polymer substrate; wherein the heat dissipation layer is formed from CNT, conductive polymer, graphite, or a combination thereof.

[0012] WO 2004/040225 A1 discloses a heat exchange wall for a heat exchanger comprising two sets of nested medium flow channels. The medium flow channels each form a primary medium circuit and a secondary medium circuit through which two medium streams can flow, which are physically separated by the heat exchange wall and are in heat exchange contact. The heat exchange wall is at least partially designed as a foil laminate comprising a first layer serving as a carrier layer made of a material with a lower thermal conductivity coefficient than a metal, for example, plastic, and a heat-conducting second layer arranged thereon, which consists of a number of layer parts arranged at a distance from one another, at least in the direction of medium transport on the side of the heat-conducting second layer.

[0013] The present invention is based on the object of improving the safety of a rechargeable battery.

[0014] The object of the invention is achieved with the heat transfer device mentioned at the outset, in which the first composite material has a second conductive layer on the second plastic layer and connected thereto, which second conductive layer is a metal layer or a metal-deposited polymer layer or a polymer layer made of a conductive polymer and which has an electrical conductivity at 25 °C according to DIN EN 50994:2017-11 of at least 1 S/m and/or a thermal conductivity at 25 °C according to ASTM E1530 of at least 0.1 W/mK.

[0015] Furthermore, the object is achieved with the accumulator mentioned at the outset, in which the heat transfer device is designed according to the invention.

[0016] The advantage here is that the second conductive layer provides, on the one hand, an improved

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A monitoring system can be provided for the accumulator. This makes it possible to detect damage to the heat transfer element through the electrical contact between the two conductive layers even before the heat transfer device has developed a leak. For example, a foreign body penetrating the heat transfer element from the outside can be detected in this way. On the other hand, the second conductive layer also makes it possible, in addition to or as an alternative, to enable faster cooling or temperature control of the cell, since the second conductive layer enables a better distribution of thermal energy across the surface of the heat transfer element.

[0017] According to one embodiment of the invention, the composite material can have a third plastic layer on top of the second conductive layer. This provides protection for the second conductive layer, allowing it to be made thinner. This not only allows the electrical resistance of the layer to be modified, but also the rigidity or flexural flexibility of the heat transfer element to be modified, allowing the heat transfer device to better adapt to the contours of a battery.

[0018] It is also advantageous if, according to one embodiment, the third plastic layer is liquid-tight (waterproof) and/or has a water vapor permeability according to DIN 53122-1 / DIN 53122-A of a maximum of 200 g/m²d. Due to this third plastic layer, cracks occurring inside the heat transfer element or heat transfer device can also be detected before a leak occurs, since fluid passing through the inner layers can be prevented from escaping from the fluid channel of the heat transfer device by the third plastic layer.

[0019] According to another embodiment of the invention, the first and second conductive layers can be made of a metallic material, in particular of the same metallic material. This allows, on the one hand, an improvement in the aforementioned effects regarding electrical conductivity and thermal conductivity while simultaneously allowing a thinner design of the heat transfer element. On the other hand, the detector structure can be simplified by using the same metallic materials.

[0020] According to another embodiment of the invention, the second conductive layer can have a second layer thickness that is equal to or greater than the first layer thickness of the first conductive layer. In particular, with larger layer thicknesses, the thermal resistance of the heat transfer element can be increased, thus achieving a more uniform temperature distribution in the accumulator. This is particularly advantageous in cold outside temperatures when the storage elements need to be heated to achieve a better operating temperature.

[0021] Further embodiments of the invention may provide for the first conductive layer to be arranged directly on the first plastic layer, the second plastic layer to be arranged directly on the first conductive layer, and the second conductive layer to be arranged directly on the second plastic layer. Optionally, the third plastic layer may be arranged directly on the second conductive layer. This not only allows for a simpler layer structure, but also allows for improved heat transfer through the heat transfer element or improved measurement of electrical quantities.

[0022] To increase the performance of the heat transfer device, according to one embodiment of the invention, the element body can be provided with a second heat transfer element that is identical in design to the first heat transfer element. This makes it easier to design the heat transfer device so that it can be applied to multiple storage elements.

[0023] According to a further embodiment of the invention, to protect the heat

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transmission device, it can also be provided that the element body has a protective element made of a fiber-reinforced plastic which has an E-modulus according to ISO 527 of at least 100 MPa.

[0024] For a better understanding of the invention, it is explained in more detail with reference to the following figures.

[0025] They show in a simplified, schematic representation:

[0026] Fig. 1 shows a motor vehicle with an electric motor and an accumulator;

[0027] Fig. 2 shows an accumulator in an oblique view with a heat transfer element; [0028] Fig. 3 shows the accumulator according to Fig. 1 in an oblique view without a heat transfer element; [0029] Fig. 4 shows a section of the heat transfer element;

[0030] Fig. 5 shows a section of the heat transfer element;

[0031] Fig. 6 shows a section of a further embodiment of a heat transfer element;

[0032] Fig. 7 A section of a variant of a heat transfer element.

[0033] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference numerals or identical component designations, whereby the disclosures contained in the entire description can be applied mutatis mutandis to identical parts with identical reference numerals or identical component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these positional information must be applied mutatis mutandis to the new position in the event of a change in position.

[0034] Information on standards always refers to the latest version of these standards in force on the filing date of the first application giving rise to the priority, unless explicitly stated otherwise.

[0035] Fig. 1 shows a motor vehicle 1, for example a passenger car. The motor vehicle 1 has an electric motor 2 and a battery 3. Preferably, the electric motor 2 is the sole drive of the motor vehicle 1.

[0036] It should be noted that the invention can also be used in other motor vehicles, such as a truck, or in a boat or in other areas of application.

[0037] In Figs. 2 and 3, the accumulator 3, i.e. a rechargeable battery (secondary battery), is shown in an oblique view, wherein Fig. 2 shows the accumulator 3 with a heat transfer device 4 and Fig. 3 shows the accumulator 3 without this heat transfer device 4.

[0038] The accumulator 3 comprises a plurality of storage elements 5 or cells for storing electrical energy (hereinafter referred to simply as storage element 5). The storage elements 5 can be cuboid-shaped, cubic, cylindrical, etc.

[0039] Since the basic structure of such accumulators 3 (in particular for e-mobility) is known from the relevant prior art, reference is made to it to avoid repetition.

[0040] As can be seen from the comparison of both Figs. 2 and 3, the heat transfer device 4 is arranged on one side of the accumulator 3. However, it can also be provided that the heat transfer device 4 extends over at least two surfaces of the accumulator 1, for example, above and laterally and optionally below. Alternatively or additionally, the heat transfer device 4 can also be arranged between the storage elements 5 or only below the storage elements 5 or only in the area of the side

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walls of the storage elements 5.

[0041] The heat transfer device 4 can extend over all storage elements 5 (as can be seen in Fig. 1), so that all storage elements 5 can be cooled or tempered with only one heat transfer device 4. However, it is also possible to provide several heat transfer devices 4 in the accumulator 3 for the storage elements 5, for example, two, three, or four.

[0042] Preferably, the storage element(s) 5 are located directly (immediately) on the heat transfer device(s) 4.

[0043] It should be noted that the terms top side, etc., refer to the installation position of the accumulator 3.

[0044] It should also be noted that the memory elements 5 can be designed in a modular manner, so that they can also be referred to as memory modules.

[0045] It should also be noted that in the present description, the accumulator 3 is described with multiple storage elements 5. However, the accumulator 3 can also have only one storage element 5. The statements in the description can therefore also be applied accordingly to this embodiment.

[0046] In all embodiments, the heat transfer device 4 comprises a first heat transfer element 6 and preferably also a second heat transfer element 7, or consists of these, as can be seen from Figs. 4 and 5. The first and second heat transfer elements 6, 7 can also be combined into a single element by bending (folding) the first heat transfer element 6 at one edge.

[0047] The first heat transfer element 6 and the second heat transfer element 7 are preferably of identical design, so that in the following, reference is made only to the first heat transfer element 6. The explanations in this regard can be transferred to the second heat transfer element 7. However, it is possible for the second heat transfer element 7 to have a different structure, for example, more or fewer layers than the first heat transfer element 6. The materials for this layer structure of the second heat transfer element 7 can be selected for these embodiments from the materials described for the first heat transfer element 6.

[0048] Furthermore, there is the possibility that, according to an embodiment variant, the first heat transfer element 6 is combined with a protective element 8 which has a higher flexural rigidity than the first heat transfer element 6, as will be described in more detail with reference to Fig. 7.

[0049] The first heat transfer element 6 is formed as a multi-layered first foil material.

[0050] The multilayer foil material of the first heat transfer element 6 of the heat transfer device 4 rests against the storage elements 5, particularly directly. Since the multilayer foil material is flexible, i.e., not rigid, it can adapt to unevenness of the storage elements 5 or between the storage elements 5. A leveling compound between the heat transfer device 4 and the storage elements 5 is not required.

[0051] Furthermore, the heat transfer device 4 comprises at least one fluid channel 9, which extends from at least one connection element 10 for the supply of a working fluid to at least one connection element 11 for the discharge of the working fluid. The at least one fluid channel 9 is formed between the first and second heat transfer elements 6, 7 or between two layers of the first heat transfer element 6 or between the first heat transfer element 6 and the protective element 8 by only partially connecting the first heat transfer element 6 to the second heat transfer element 7 or the protective element 8 or the two layers of the first heat transfer element 6.

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For example, the at least one fluid channel 9 can be produced by gluing or welding the film materials or elements to form connecting regions 12, such as webs (see Fig. 5). The at least one fluid channel 9 is created in the unconnected regions adjacent to the connecting regions 12. The at least one fluid channel 9 is therefore not formed by a separate component. In general, the connecting techniques are preferably selected such that no additional measures are required to achieve a liquid-tight connection.

[0052] The fluid channel 9 can be arranged in a meandering shape in the heat transfer device 4, as can be seen from Fig. 4. The concrete representation of the course of the at least one fluid channel 9 in Fig. 4 is to be understood only as an example. The optimized course of the at least one fluid channel 9 depends, among other things, on the amount of heat to be dissipated, the geometry of the accumulator 3, etc. It can also be provided that more than one fluid channel 9 is formed or arranged in the heat transfer device 4. In this case, it is advantageous if the multiple fluid channels 9 have common connection elements 10, 11, each of which opens into a collecting channel, from which the fluid channels 9 branch off or into which they open. However, it is also possible for each fluid channel 9 to have its own connection elements 10, 11.

[0053] The working fluid flowing through the heat transfer device 4 is in particular a liquid, for example a water-glycol mixture, but may also be a gas.

[0054] The first heat transfer element 6 is a composite material. In a first embodiment, it comprises, in the specified order from inside to outside, a first plastic layer 13, a first conductive layer 14, a second plastic layer 15, and a second conductive layer 16, one above the other.

[0055] The first conductive layer 14 has an electrical conductivity at 25°C according to DIN EN 50994:2017-11 of at least 1 S/m, in particular between 1 x 10 5 S/m (1 x 10 exponent 2 S/m) and 1 x 10 5 S/m (1 x 10 exponent 8 S/m), and/or a thermal conductivity at 25°C according to ASTM E1530 of at least 0.1 W/mK, in particular between 20 W/mK and 450 W/mK. Although metallic first conductive layers 14 with correspondingly higher values for electrical conductivity or thermal conductivity are preferred, materials with low values of down to at least 1 S/m or 0.1 W/mK can also be used for thin first conductive layers 14 (see information on layer thickness below).

[0056] However, it should be noted that the layer thickness specifications are not limited to materials with low electrical conductivity or low thermal conductivity.

[0057] The second conductive layer 16 has an electrical conductivity at 25 °C according to DIN EN 50994:2017-11 of at least 1 S/m, in particular between 1 x 10 5 S/m (1 x 10 exponent 2 S/m) and 1 x 10 5 S/m (1 x 10 exponent 8 S/m), and/or a thermal conductivity at 25 °C according to ASTM E1530 of at least 0.1 W/mK, in particular between 20 W/mK and 450 W/mK. The same applies to the second conductive layer 16: although metallic second conductive layers 14 with correspondingly higher values for electrical conductivity or thermal conductivity are preferred, materials with low values of down to at least 1 S/m or 0.1 WmK can also be used for thin first conductive layers 14 (see information on layer thickness below).

[0058] The first plastic layer 13 is arranged directly adjacent to the at least one fluid channel 9 and delimits it, so that the working fluid flowing through the fluid channel 9 during operation of the heat transfer device 4 is in direct contact with the first plastic layer 13. In this embodiment, the second conductive layer 16 forms the outermost layer, the layer of the composite material furthest from the fluid channel 9.

[0059] According to one embodiment variant, it can be provided that the first conductive layer 14 is arranged directly on the first plastic layer 13, the second plastic layer 15 is arranged directly on the first conductive layer 14 and the second conductive layer 16 is arranged directly on the second plastic layer 15.

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[0060] The first conductive layer 14 can be formed by a foil or by vapor deposition of the first plastic layer 13, e.g., a PVD layer. The second conductive layer 16 can be formed by a foil or by vapor deposition of the second plastic layer 15, e.g., a PVD layer.

[0061] The first plastic layer 13 and/or the second plastic layer 15 preferably consists of at least 80% to 100% by weight of a thermoplastic or an elastomer, i.e., a polymer. The thermoplastic can be selected from a group comprising or consisting of polyethylene (PE), polyoxymethylene (POM), polyamide (PA), in particular PA 6, PA 66, PA 11, PA 12, PA 610, PA 612, polyphenylene sulfide (PPS), polyethylene terephthalate (PET), cross-linked polyolefins, preferably polypropylene (PP), and polytetrafluoroethylene (PTFE). The elastomer can be selected from a group comprising or consisting of thermoplastic elastomers such as thermoplastic vulcanizates, olefin-, amine-, ester-based, thermoplastic polyurethanes, in particular ether/ester-based thermoplastic elastomers, styrene block copolymers, silicone elastomers.

[0062] It should be mentioned at this point that a polymer in the sense of the invention is understood to mean a synthetic or natural polymer which is produced from corresponding monomers.

[0063] Preferably, the first plastic layer 13 consists of a so-called sealing film. This has the advantage that, for example, the first heat transfer element 6 can be directly connected to the second heat transfer element 7 or the protective element 8.

[0064] The second plastic layer 15 can consist, in particular, of PA or PET. It is also possible for the second plastic layer 15 to consist of several sublayers, for example, a combination of PA and PET, in which case the PET sublayer is preferably arranged farther away from the fluid channel 9 than the PA sublayer.

[0065] However, it is also possible to use other plastics, such as thermosetting plastics or thermosetting materials, which are then bonded together, for example, with an adhesive. Two-component polyurethane- or silicone-based adhesive systems, or even hot-melt adhesive systems, are particularly suitable for this purpose.

[0066] In general, an adhesive layer can be arranged between two layers of the first heat transfer element 6, in particular over the entire surface. For example, the first plastic layer 13 can be connected to the first conductive layer 14 and/or the first conductive layer 14 to the second plastic layer 15 and/or the second plastic layer 15 to the second conductive layer 16 via an adhesive layer (not shown).

[0067] The first conductive layer 14 and/or the second conductive layer 16 is/are preferably (a) metal layer(s). In particular, the first conductive layer 14 and/or the second conductive layer 15 is/are an aluminum layer or consists of the same metallic material. However, other metals can also be used, such as copper or silver or metallic alloys. The first conductive layer 14 and/or the second conductive layer 16 can also be formed from a different material, such as a conductive polymer, e.g., polymers containing graphite or carbon black, or metal particles or metal fibers, such as PE, PP, PA, PET, or polypyrrole or polyethene.

[0068] The first conductive layer 14 and/or the second conductive layer 16 can, for example, have a layer thickness between 5 µm and 100 µm. According to one embodiment, it can be provided that the second conductive layer 16 has a second layer thickness that is equal to or greater than a first layer thickness of the first conductive layer 14. Conversely, however, the first conductive layer 14 can also have a greater layer thickness than the second conductive layer 16. However, embodiments with a layer thickness of less than 5 µm are also possible, for example by vapor-depositing a metal, in particular aluminum, onto one of the plastic layers 13, 15 or depositing it using a PVD process. In this case, the first conductive layer 14 and/or the second conductive layer 16 can also have a layer thickness of only a few atomic layers (for example-

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between 2 and 10 atomic layers).

[0069] The second conductive layer 16 may also consist of a conductive print on the plastic layer 15. For example, the second conductive layer 16 may be made of a carbon paste, a lacquer, or a printable material mixed with conductive particles, such as a metal or graphite, or carbon black.

[0070] The first plastic layer 13 and/or the second plastic layer 15 may have a layer thickness between 10 µm and 200 µm.

[0071] In addition to bonding the individual layers of the first film material with adhesives, coextrusion and extrusion coating can also be used as bonding options. Of course, a combination is also possible, so that several polymers are coextruded and adhesively laminated to one another with an extrusion-coated metal layer. In general, all known processes for producing composite films or film laminates can be used.

[0072] The second plastic layer 15 can consist of or comprise the same polymer as the first plastic layer 13. However, the second plastic layer 15 can also consist of or comprise a different polymer. For example, the first plastic layer 13 can consist of PP, and the further plastic layer 15 can consist of PA, PET, or PTFE, or comprise these polymers.

[0073] It should be noted again that the first and second heat transfer elements 6, 7 can be of identical design. Thus, Fig. 5 also shows the four-layer structure of the first heat transfer element 6 for the second heat transfer element 7, wherein the first plastic layer 13 is arranged to delimit the fluid channel 9, in particular directly delimiting it, and the second conductive layer 16 forms the outer layer.

[0074] The first conductive layer 14 and the second conductive layer 16 can be arranged in the first heat transfer element 6 so as to be electrically insulated from the fluid channel 9. This can be achieved most easily with the first plastic layer 13. However, other/additional layers can also be provided for this purpose in the first heat transfer element 6, so that the first conductive layer 14 and the second conductive layer 16 are not in contact with the fluid channel 9 during normal operation of the heat transfer device 4.

[0075] All layers of the first and/or second heat transfer element 6, 7 preferably have the same surface area, i.e., they are preferably the same size. Furthermore, all layers preferably extend continuously over at least 80%, in particular 90%, particularly preferably 100%, of the total area of the layer with the largest surface area. In other words, the two conductive layers 14, 16, in particular, are not layers composed of individual conductor tracks.

[0076] In addition, all layers are preferably continuously bonded to the immediately adjacent layer over at least 80%, in particular 90%, particularly preferably 100%, of their respective surfaces facing another layer. Particularly preferably, the layers are bonded to one another over their entire surface.

[0077] The first heat transfer element 6 can, for example, have a layer structure comprising a first plastic layer 13 (e.g., made of PP) / first adhesive layer / first conductive layer 14 (e.g., made of Al) / second adhesive layer / second plastic layer 15 (e.g., made of PTFE) / third adhesive layer / second conductive layer 16 (e.g., made of Al). However, the first heat transfer element 6 can also have a layer structure comprising a first plastic layer 13 (e.g., made of PP) / first conductive layer 14 (e.g., made of Al) / second plastic layer 15 (e.g., made of PET) / second conductive layer 16 (e.g., made of Al). Mixed variants of these design variants are possible.

[0078] The first conductive layer 14 and/or the second conductive layer 16 can be used for a variety of purposes. For example, the liquid-tightness of the

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The heat transfer device 4 can be improved or the vapor permeability can be improved. On the other hand, it can also be used for measurement methods, for example, to detect a leak in the heat transfer device 4, for which the electrical resistance between the conductive layers 14, 16 is monitored. The electrical conductivity can also be used for other purposes, for example, to heat the working fluid. On the other hand, the thermal conductivity of the conductive layers 14, 16 can be used for heat distribution or heat transport. It is also possible to use the electrical conductivity in one of the two conductive layers 14, 16 and the thermal conductivity in the other of the two conductive layers 14, 16.

[0079] Regardless of the number of plastic layers 13, 15 in the layered structure of the first heat transfer element 6, all plastic layers 13, 15 are preferably formed from a polymer selected from the polymers mentioned above. Several or all plastic layers 13, 15 may be formed from the same polymer, or several or all plastic layers 13, 15 may be formed from different polymers.

[0080] This also applies to a further embodiment of the heat transfer element 6, shown in detail in Fig. 6. Reference is also made to the above explanations.

[0081] In the embodiment shown in Fig. 6, the composite material of the first heat transfer element 6 has a third plastic layer 17 arranged on the second conductive layer 16. According to one embodiment, the first heat transfer element 6 can have the layer structure of first plastic layer 13 (e.g., made of PP) / first adhesive layer / first conductive layer 14 (e.g., made of Al) / second adhesive layer / second plastic layer 15 (e.g., made of PTFE) / third adhesive layer / second conductive layer 16 (e.g., made of Al), fourth adhesive layer / third plastic layer 17 (e.g., made of PA or PET). However, the first heat transfer element 6 can also have a layered structure comprising a first plastic layer 13 (e.g., made of PP) / a first conductive layer 14 (e.g., made of Al) / a second plastic layer 15 (e.g., made of PET and/or PA) / a second conductive layer 16 (e.g., made of Al) / a third plastic layer 17 (e.g., made of PET), so that the layers are arranged directly on top of one another. Mixed variants of these design variants are also possible here. Likewise, the third plastic layer 17, like the second plastic layer 15, can consist of several sublayers, as described above for the second plastic layer 15.

[0082] In this embodiment, it is also possible for the second conductive layer 16 to be printed or vapor-deposited onto the third plastic layer 17. Reference is made to the above explanations regarding the printing or vapor-depositing of the second conductive layer 16 onto the second plastic layer 15.

[0083] The third plastic layer 17 can consist of a polymer (= 100 wt.%) or comprise at least 80 wt.% of this polymer, which is selected from the above-mentioned polymers for the first and second plastic layers 13, 15.

[0084] The third plastic layer 17 may have a layer thickness between 10 µm and 200 µm.

[0085] All plastic layers 13, 15, 17 can have the same or different layer thicknesses. For example, the first plastic layer 13 can have a layer thickness between 40 μm and 150 μm. The second and third plastic layers 15, 17 can each have a layer thickness between 10 μm and 50 μm. The first plastic layer 13 can have the greatest layer thickness compared to the second and third plastic layers 15, 17.

[0086] According to a variant of the embodiment, the third plastic layer 17 can be a liquid-tight (waterproof) layer and/or have a water vapor permeability according to DIN 53122-1 / DIN 53122-A of a maximum of 200 g/m?d, in particular between 100 g/m?d and 180 g/m?d.

[0087] As already stated above, according to an embodiment variant, which

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As shown in section in Fig. 7, it can be provided that the element body of the heat transfer device 4 comprises the protective element 8 made of a material having an elastic modulus according to ISO 527 of at least 100 MPa, in particular between 3000 MPa and 15000 MPa. The material can be, for example, a fiber-reinforced plastic, such as a glass fiber or generally (mineral) fiber-reinforced polymer, such as PP, PAG.

[0088] The connection of the first heat transfer element 6 to the protective element 8 can be effected, for example, directly with the first plastic layer 13 or via an adhesive (for example one of those mentioned above).

[0089] The protective element 8 can have a layer thickness between 1 mm and 10 mm.

[0090] In the embodiment shown in Fig. 7, the protective element 8 forms part of the at least one fluid channel 9. However, the protective element 8 can also be arranged covering the first or second heat transfer element 6, 7.

[0091] In the event that one or more of the conductive layer(s) 14, 16 is/are applied directly to one of the plastic layers 12, 15, 17, this can also be done, for example, using a printing process (e.g. screen printing, roll printing, inkjet printing, gravure printing, intaglio printing, planographic printing, stamp printing), by spraying, vapor deposition, plasma coating, sputtering, powder coating, etc.

[0092] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure of the heat transfer device 4, it is not necessarily shown to scale.

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LIST OF REFERENCE SYMBOLS

1 motor vehicle

2 electric motor

3 accumulator

4 Heat transfer device 5 Storage elements

6 Heat transfer element

7 Heat transfer element

8 protective element

9 Fluid channel

10 Connection element 11 Connection element 12 Connection area 13 Plastic layer

14 layer 15 plastic layer 16 layer

17 plastic layer

Claims (10)

A 'hes AT 527 873 B1 2025-09-15 Ss N patent claims 1. Heat transfer device (4) comprising an element body having at least one fluid channel (9), wherein the fluid channel (9) is at least partially formed by a first heat transfer element (6), wherein the first heat transfer element (6) is formed from a first composite material having, one above the other in the specified order, a first plastic layer (13), a first conductive layer (14), and a second plastic layer (15), wherein the first conductive layer (14) has an electrical conductivity at 25°C according to DIN EN 50994:2017-11 of at least 1 S/m and/or a thermal conductivity at 25°C according to ASTM E1530 of at least 0.1 W/mK, and wherein the first conductive layer (14) is a metal layer or a metal-deposited polymer layer or a polymer layer made of a conductive polymer, characterized in that the first composite material is applied to the second plastic layer (15) and a second conductive layer is connected thereto. (16) which is a metal layer or a metal-deposited polymer layer or a polymer layer made of a conductive polymer and which has an electrical conductivity at 25 °C according to DIN EN 50994:2017-11 of at least 1 S/m and/or a thermal conductivity at 25 °C according to ASTM E1530 of at least 0.1 W/mK. 2. Heat transfer device (4) according to claim 1, characterized in that the composite material has a third plastic layer (17) on the second conductive layer (16). 3. Heat transfer device (4) according to claim 2, characterized in that the third plastic layer (17) is liquid-tight. 4. Heat transfer device (4) according to one of claims 1 to 3, characterized in that the first and the second conductive layer (14, 16) consist of a metallic material, in particular of the same metallic material. 5. Heat transfer device (4) according to one of claims 1 to 4, characterized in that the second conductive layer (16) has a second layer thickness which is equal to or greater than a first layer thickness of the first conductive layer (14). 6. Heat transfer device (4) according to one of claims 1 to 5, characterized in that the first conductive layer (14) is arranged directly on the first plastic layer (13), the second plastic layer (15) is arranged directly on the first conductive layer (14) and the second conductive layer (16) is arranged directly on the second plastic layer (15). 7. Heat transfer device (4) according to one of claims 2 to 5, characterized in that the first conductive layer (14) is arranged directly on the first plastic layer (13), the second plastic layer (15) is arranged directly on the first conductive layer (14), the second conductive layer (16) is arranged directly on the second plastic layer (15) and the third plastic layer (17) is arranged directly on the second conductive layer (16). 8. Heat transfer device (4) according to one of claims 1 to 7, characterized in that the element body has a second heat transfer element (7) which is designed identically to the first heat transfer element (6). 9. Heat transfer device (4) according to one of claims 1 to 8, characterized in that the element body has a protective element (8) made of a fiber-reinforced plastic which has an E-modulus according to ISO 527 of at least 100 MPa. 10. Accumulator (3) with at least one storage element (5) for storing electrical energy and at least one heat transfer device (4) for cooling or tempering the storage element (5), characterized in that the heat transfer device (4) is designed according to one of claims 1 to 9. 3 sheets of drawings