Structure with thermal insulation properties

Abstract

The present disclosure relates to a multi-layer structure comprising a polymer foam layer and at least one spacer layer comprising a plurality of spacer elements, each spacer element having a protruding portion and two opposing end portions, and at least one end portion of each spacer element being completely embedded within the polymer foam layer.

Description

[Technical Field]

[0001] The present disclosure relates generally to the field of multilayer structures, and more particularly to the field of multilayer structures having thermal insulating properties. The present disclosure also relates to methods of making such multilayer structures and their use for industrial applications, particularly for thermal management applications in the transportation industry. [Background technology]

[0002] Vehicle electrification is currently one of the biggest trends in the automotive industry. Due to this trend, the development of electric vehicle batteries suitable as propulsion and energy storage devices for the electric energy supplied by batteries is a major focus in the automotive industry. Electric vehicle batteries are used to power the propulsion systems of battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs). These batteries are typically lithium-ion batteries and are designed with high ampere-hour capacities. The trend in electric vehicle battery development is to increase the energy density (kWh / kg) in the battery, enabling longer distances and shorter battery charging times.

[0003] Due to the high energy density of electric vehicle batteries and the high energy flow during battery charging or discharging, there is a risk of hot spots and thermal runaway events occurring, where heat generated by the decomposition of a battery cell propagates very quickly to adjacent cells, a chain reaction that can result in explosions or fires throughout the electric vehicle.

[0004] Furthermore, during the normal life cycle of these energy storage devices, particularly during high-rate charge and discharge cycles of electric vehicle batteries, the battery cells used in such battery modules tend to expand and contract continuously. These expansion / contraction cycles can subject the battery cells to significant pressure conditions, which in turn can lead to not only mechanical damage to the battery cells.

[0005] In this context, the use of thermal management solutions has rapidly emerged as a way to mitigate temperature rise in battery assemblies. One partial solution is disclosed in U.S. Patent Application Publication No. 2007 / 0259258(A1) (Buck), which discloses the use of heat-absorbing materials to absorb heat generated by battery cells in a battery pack assembly and transfer it out of the assembly case, thereby maintaining a lower temperature inside each battery pack and the entire battery assembly. Another partial solution is described in U.S. Patent Application Publication No. 2019393574(A1) (Goeb et al.), which discloses the use of thermally conductive gap-filler compositions including thermally conductive filler materials to cool battery assemblies. Yet another partial solution is described in US Patent Application Publication No. 2016 / 0308186(A1) (Han), which discloses a battery module including battery cells arranged adjacent to each other along a first direction, spacers between the adjacent battery cells, and a multi-layer insulating sheet between the adjacent battery cells together with the spacers, the multi-layer insulating sheet including a plurality of insulating layers extending parallel to the surfaces of the battery cells. Summary of the Invention

[0006] According to one aspect, the present disclosure relates to a multi-layer structure comprising a polymer foam layer and at least one spacer layer comprising a plurality of spacer elements, each spacer element comprising a protruding portion and two opposing end portions, and at least one end portion of each spacer element being completely embedded within the polymer foam layer.

[0007] According to another aspect, the present disclosure is directed to a method for manufacturing the multilayer structure described above, comprising the steps of providing a polymer foam layer described above, providing at least one spacer layer described above, and applying the at least one spacer layer onto the polymer foam layer.

[0008] According to yet another aspect, the present disclosure relates to the use of the above multilayer structure for thermal management applications in industrial applications, particularly in the transportation industry. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of an exemplary coating apparatus and method for producing an exemplary polymer foam layer for use in the present disclosure. [Figure 2] 1 is a schematic diagram of an exemplary coating apparatus and method for producing a multi-layer structure according to an exemplary embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of another exemplary coating apparatus and method for producing a multi-layer structure according to another exemplary aspect of the present disclosure. [Figure 4] FIG. 2 is a schematic diagram of yet another exemplary coating apparatus and method for producing a multi-layer structure according to yet another exemplary aspect of the present disclosure. [Figure 5] FIG. 1 is a cross-sectional view of a multi-layer structure according to an exemplary embodiment of the present disclosure. [Figure 6] FIG. 2 is a cross-sectional view of a multi-layer structure according to another exemplary embodiment of the present disclosure. [Figure 7A] FIG. 2 is a top view of an exemplary spacer layer according to an exemplary aspect of the present disclosure. [Figure 7B] FIG. 2 is a top view of an exemplary spacer layer according to an exemplary aspect of the present disclosure. [Figure 7C] FIG. 2 is a top view of an exemplary spacer layer according to an exemplary aspect of the present disclosure. [Figure 7D] FIG. 2 is a top view of an exemplary spacer layer according to an exemplary aspect of the present disclosure. [Figure 8] FIG. 2 is a perspective view of a spacer layer according to an exemplary embodiment of the present disclosure. [Figure 9] 1 illustrates an exemplary battery module assembly according to one aspect of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] According to a first aspect, the present disclosure relates to a multi-layer structure comprising a polymer foam layer and at least one spacer layer comprising a plurality of spacer elements, each spacer element comprising a protruding portion and two opposing end portions, and at least one end portion of each spacer element being fully embedded within the polymer foam layer.

[0011] In the context of the present disclosure, it has surprisingly been found that the multilayer structures have excellent thermal insulation properties, excellent thermal runaway barrier performance, and excellent compressibility properties. In some advantageous aspects, the multilayer structures further have excellent heat resistance and stability, even at temperatures and long-term exposure to heat up to 600°C.

[0012] The described multilayer structures are further characterized by one or more of the following advantageous benefits: a) excellent cushioning performance for individual battery cells when used in a battery assembly; b) excellent resistance to high compressive forces and high-pressure conditions; c) ability to maintain foam structure for the polymer foam layer even under high-pressure conditions; d) easy and cost-effective manufacturing methods based on readily available starting materials and minimal manufacturing steps; e) simplicity and versatility of the structure; f) excellent formulation flexibility for the polymer foam layer for use herein; g) excellent construction and design flexibility for the spacer layer into various forms, sizes, and shapes; h) ability to fine-tune the compression properties of the multilayer structure to suit specific applications, operating conditions, and battery cell types; i) excellent pressure distribution for individual battery cells when used in a battery assembly; j) excellent processability and conversion properties; k) low thermal conductivity; l) ability to be manufactured at relatively thin thicknesses; m) ready-to-use structures, particularly for thermal management applications; n) long-term durability of energy storage assemblies using the multilayer structures of the present disclosure; and o) ability to adhere to various substrates, such as metal or polymer surfaces, without the need for adhesion-promoting processing steps or compositions.

[0013] These are particularly unexpected findings in many respects. First, good cushioning performance and resistance to high compressive forces and pressure conditions are considered self-contradicting properties. Also, thermal insulation and thermal stability are not typically expected to be obtained in compressible (soft) polymer foam layers, especially foam layers with relatively low thickness, and more specifically foam layers subjected to compression.

[0014] In the context of the present disclosure, the applicant was faced with the technical challenge of designing a cushioning structure with a delicate balance of excellent compression properties, resistance to high compressive forces, and thermal insulation properties.

[0015] Without being bound by theory, it is believed that these superior properties and performance attributes are due to a combination of technical features, particularly: a) the use of a polymer foam layer; and b) the use of the particular spacer layer described above, in which at least one end portion of each spacer element is completely embedded within the polymer foam layer.

[0016] Furthermore, without being bound by theory, it is believed that the spacer layer advantageously acts as a counterforce means to prevent, or at least substantially reduce, unwanted compressive forces endured by the polymer foam not only during normal charge and discharge cycles of the electric vehicle battery, but also during more extreme conditions, such as a thermal runaway event. More specifically, it is believed that the spacer layer has the ability to maintain a critical and minimum gap between battery cells, even under high pressure conditions, while still ensuring adequate cushioning properties necessary to allow the battery cells to expand and contract during their lifecycle. It is believed that this ability to maintain this set of properties directly and advantageously contributes to the excellent thermal insulation properties provided by the multilayer structures of the present disclosure.

[0017] The above detailed array of advantageous properties provided by the multilayer structures described herein is even more surprising in view of the expectation that the spacer layer described above would adversely affect the foam structure of the polymer foam layer, thereby compromising its thermal insulation properties.

[0018] Thus, the multilayer structures of the present disclosure are suitable for use in a variety of industrial applications, particularly thermal management applications. The multilayer structures of the present disclosure are particularly suitable for thermal management applications in the transportation industry (particularly the automotive industry), particularly as thermal barriers, more specifically as thermal runaway barriers. The multilayer structures described herein are particularly suitable for use as spacers with thermal runaway barrier properties in rechargeable electrical energy storage systems, particularly battery modules. Advantageously, the multilayer structures of the present disclosure can also be used in the manufacture of battery modules, particularly electric vehicle battery modules and assemblies. In beneficial aspects, the multilayer structures described herein are particularly suitable for manual or automated handling and applications, particularly high-speed robotic equipment, due to their excellent robustness, dimensional stability, and handling properties. In some advantageous aspects, the described multilayer structures can also meet challenging fire regulatory standards due to their outstanding flammability and thermal stability properties.

[0019] In the context of this disclosure, the term "adjacent" is meant to refer to two superimposed films or layers that are disposed directly adjacent to one another, i.e., abutting one another, or that are not disposed directly next to one another, i.e., at least one additional film or layer is disposed between the first two superimposed films or layers. The terms top and bottom layer or film, respectively, are used herein to refer to the position of a layer or film relative to the surface of a substrate that carries such layer or film in the process of forming a polymer foam layer. The direction in which a movable substrate, layer, or film moves is referred to herein as the downstream direction. The relative terms upstream and downstream refer to positions along the extension of the substrate.

[0020] The polymer foam layer for use herein is not particularly limited, and suitable polymer foam layers for use herein can be readily identified by those of ordinary skill in the art in light of this disclosure.

[0021] According to advantageous embodiments, the polymer foam layer for use herein comprises a material that has a weight loss of 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or even 25% or less after 3 minutes at 600°C, as measured according to the Thermal Stability Test Method described in the Experimental Section.

[0022] The types of polymer foam layers described above are typically referred to as heat resistant materials or heat resistant polymer foam layers.

[0023] According to an exemplary embodiment, the polymer foam layer for use in the multi-layer structure of the present disclosure comprises a material selected from the group consisting of an elastomeric material, a thermoplastic material, a thermoplastic elastomeric material, a thermoplastic non-elastomeric material, a thermoset material, and any combination or mixture thereof.

[0024] In one advantageous aspect, the polymer foam layer for use herein comprises a material selected from the group consisting of silicone elastomers, fluorosilicone rubbers, aromatic polyamides, polybenzimidazoles, polysulfides, polyimides, polysulfones, polyetherketones, fluorocarbons, polyisoprene, polybutadiene, polychloroprene, polyurethanes, polyolefins (particularly PE, PP and EVA), polystyrene, and any combination or mixture thereof.

[0025] More advantageously, the polymer foam layer for use herein comprises a material selected from the group consisting of elastomeric materials.

[0026] In another more advantageous aspect, a polymer foam layer for use herein reaches a compression value of at least 60% when using a compression force of 700 kPa or less, 600 kPa or less, 500 kPa or less, 400 kPa or less, 300 kPa or less, 250 kPa or less, 200 kPa or less, 150 kPa or less, 100 kPa or less, 80 kPa or less, 60 kPa or less, or even 50 kPa or less, as measured according to the Compression Test Method described in the Experimental Section. This type of polymer foam layer is typically referred to as a (relatively highly) compressible polymer foam layer (or soft polymer foam layer).

[0027] In another more advantageous aspect, the polymer foam layer for use herein comprises a material selected from the group consisting of silicone elastomers, particularly silicone rubbers, and more particularly organopolysiloxane polymers.

[0028] In one particularly advantageous aspect of the present disclosure, the polymer foam layer used herein is a silicone rubber foam layer.

[0029] According to an advantageous embodiment, the silicone rubber foam layer for use herein is obtained from a curable, foamable precursor of the silicone rubber foam layer, in particular an in-situ foamable precursor composition.

[0030] The silicone rubber foam precursor composition for use herein is not particularly limited, as long as it is curable and foamable. Any curable foamable precursor of silicone rubber foam known in the art may be used in the context of the present disclosure. Suitable curable foamable precursors of silicone rubber foam for use herein can be easily identified by those skilled in the art in light of the present disclosure.

[0031] According to a more advantageous embodiment, the precursor of the silicone rubber foam layer for use herein is a two-part composition.

[0032] In an exemplary embodiment, the two-part silicone rubber foam precursor composition is selected from the group consisting of an addition-cure two-part silicone composition, a condensation-cure two-part silicone composition, and any combination or mixture thereof.

[0033] In a preferred embodiment, the silicone rubber foam precursors for use herein comprise addition-curable two-part silicone compositions, particularly addition-curable two-part organopolysiloxane compositions.

[0034] Suitable addition-curable two-part organopolysiloxane compositions for use herein as silicone rubber foam precursors can be readily identified by those skilled in the art. Exemplary addition-curable two-part organopolysiloxane compositions for use herein are described, for example, in U.S. Pat. No. 4,593,049 (Bauman et al.).

[0035] According to a particularly advantageous aspect of the present disclosure, a silicone rubber foam precursor for use herein comprises at least one organopolysiloxane compound A, at least one organohydrogenpolysiloxane compound B containing at least two, particularly at least three, hydrogen atoms per molecule, at least one hydroxyl-containing compound C, an effective amount of a curing catalyst D, particularly a platinum-based curing catalyst, and, optionally, a blowing agent.

[0036] In an exemplary embodiment, at least one organopolysiloxane compound A for use herein has the formula: [ka] [In the formula, R and R" are independently C1 to C 30 in particular R is an alkyl group selected from the group consisting of methyl, ethyl, propyl, trifluoropropyl, and phenyl, optionally R is a methyl group; R' is C1 to C 20and in particular R' is selected from the group consisting of vinyl, allyl, hexenyl, decenyl, and tetradecenyl, more particularly R' is a vinyl group; R" is an alkyl group, especially methyl, ethyl, propyl, trifluoropropyl, phenyl, especially R" is a methyl group; n is an integer having a value in the range of 5 to 1000, in particular 5 to 100].

[0037] In another exemplary embodiment, the at least one hydroxyl-containing compound C for use herein is selected from the group consisting of alcohols, polyols, particularly polyols having 3 to 12 carbon atoms per molecule and an average of at least two hydroxyl groups, silanols, silanol-containing organopolysiloxanes, silanol-containing silanes, water, and any combination or mixture thereof.

[0038] In yet another exemplary embodiment, the at least one hydroxyl-containing compound C for use herein is selected from the group consisting of silanol-containing organopolysiloxanes.

[0039] According to an advantageous aspect of the present disclosure, the polymer foam layer for use herein comprises: a) providing a substrate; b) providing a first solid film and applying it onto a substrate; c) providing a coating tool having an upstream side and a downstream side, the coating tool being offset from the substrate to form a gap perpendicular to the surface of the substrate; d) moving the first solid film downstream relative to the coating tool; e) providing a curable (and foamable) precursor of a polymer foam to the upstream side of the coating tool and coating the polymer foam precursor as a layer through the gap onto the substrate with the first solid film; f) providing a second solid film and applying the second solid film (at least partially) along the upstream side of the coating tool such that the first solid film and the second solid film are applied simultaneously with the formation of (adjacent) layers of silicone rubber foam precursor; g) foaming or allowing the polymer foam precursor to foam; h) curing or allowing to cure the layer of polymer foam precursor to form a polymer foam layer; i) optionally subjecting the layer of polymer foam precursor to a heat treatment; and optionally removing the first solid film and / or the second solid film from the polymer foam layer.

[0040] A schematic diagram of an exemplary method for producing a polymer foam layer (particularly a silicone rubber foam layer) and a coating apparatus suitable for use in the production method is shown in Figure 1. The coating apparatus 1 comprises a substrate 2, a coating tool 7 in the form of a coating knife, an unwind roll 11 and a take-up roll 12 for a first solid film 5, and an unwind roll 9 and a take-up roll 10 for a second solid film 6. The downstream direction 8 in which the (substrate 2 with) first solid film 5 moves relative to the coating tool 7 is represented by an arrow with a corresponding reference number.

[0041] In a typical embodiment of the present disclosure, a curable, expandable polymer foam precursor 3 is provided to the upstream side of a coating tool 7, thereby coating the polymer foam precursor 3 through the gap as a layer onto a substrate 2 with a first solid film 5. In FIG. 1 , the curable, expandable polymer foam precursor 3 is depicted as forming a so-called “rolling bead” on the upstream side of the coating tool 7. A second solid film 6 is applied (at least partially) along the upstream side of the coating tool 7, with the first solid film 5 and second solid film 6 being applied simultaneously with the formation of the layer of polymer foam precursor 3. The layer of polymer foam precursor 3 can then be foamed and cured into a polymer foam layer 4, which typically comprises the first solid film 5 on its bottom surface and the second solid film 6 on its top surface. Optionally, the layer of polymer foam precursor 3 can be subjected to a heat treatment, typically in an oven (not shown). In a typical embodiment, foaming of the layer of polymer foam precursor 3 produces a polymer foam layer 4, which has a greater thickness than the initial layer of polymer foam precursor 3. After processing, the first solid film 5 and / or the second solid film 6 may be removed from the polymer foam layer 4 .

[0042] According to an advantageous embodiment, the precursors of the polymer foams for use herein are in-situ foamable compositions, which means that foaming of the precursor occurs without the need for any additional compounds, in particular external compounds.

[0043] According to another advantageous aspect, the foaming of the precursors of the polymer foams for use herein is carried out using gaseous compounds, in particular hydrogen gas.

[0044] More advantageously, foaming of the precursors of polymer foams for use herein is carried out by either gas generation or gas injection.

[0045] According to a preferred embodiment, foaming of the precursors of the polymer foams for use herein is carried out by gas generation, in particular by in-situ gas generation.

[0046] In an alternative, less advantageous aspect, the polymer foam precursors for use herein further comprise an optional blowing agent.

[0047] The substrate for use herein is not particularly limited. Substrates suitable for use herein can be readily identified by those skilled in the art in light of the present disclosure.

[0048] In a typical embodiment of the present disclosure, the substrate for use herein is a temporary support used for manufacturing purposes, from which the silicone rubber foam layer is separated and removed after foaming and curing. The substrate can optionally be provided with a surface treatment adapted to enable clean removal of the silicone rubber foam layer from the substrate (through the first solid film). Advantageously, the substrate for providing the temporary support for use herein can be provided in the form of an endless belt. Alternatively, the substrate for use herein can be a non-moving (static) temporary support.

[0049] In one particular aspect of the present disclosure, the resulting polymer foam layer after foaming and curing can be separated from the substrate and wound up, for example, into a roll.

[0050] According to one advantageous aspect of the present disclosure, the substrate for use herein comprises a material selected from the group consisting of polymers, metals, ceramics, composites, and any combination or mixture thereof.

[0051] Polymer foam layers for use in the present disclosure may be obtained by a method using a coating tool with an upstream side and a downstream side, the coating tool being offset from the substrate to form a gap perpendicular to the surface of the substrate.

[0052] The coating tool for use herein is not particularly limited. Any coating tool known in the art can be used in the context of the present disclosure. Coating tools suitable for use herein can be easily identified by those skilled in the art in light of the present disclosure.

[0053] Each coating tool useful in the present disclosure has an upstream side (or upstream face) and a downstream side (or downstream face). In a typical embodiment, a coating tool for use herein further comprises a bottom portion facing the surface of the substrate that receives the polymer foam precursor. The gap is measured as the smallest distance between the bottom portion of the coating tool and the exposed surface of the substrate. The gap can be essentially uniform in the lateral direction (i.e., the direction perpendicular to the downstream direction) or can vary continuously or discontinuously in the lateral direction, respectively. The gap between the coating tool and the surface of the substrate is typically adjusted to control the thickness of each coating, in conjunction with other parameters including, for example, the speed of the substrate in the downstream direction, the type of coating tool, the angle at which the coating tool is oriented relative to the normal direction of the substrate, and the type of substrate.

[0054] In one advantageous embodiment of the present disclosure, the gap formed by the coating tool from the substrate (coating tool gap) is in the range of 10 to 3000 micrometers, 50 to 2500 micrometers, 50 to 2000 micrometers, 50 to 1500 micrometers, 100 to 1500 micrometers, 100 to 1000 micrometers, 200 to 1000 micrometers, 200 to 800 micrometers, or even 200 to 600 micrometers.

[0055] Coating tools for use herein can be positioned perpendicular to the surface of the substrate, or can be tilted so that the angle between the substrate surface and the downstream side (or downstream face) of the coating tool ranges from 50° to 130°, or even 80° to 100°. Coating tools useful in the present disclosure are typically solid and can be rigid or flexible. Coating tools for use herein can take on a variety of shapes, forms, and sizes depending on the intended application and expected properties of the silicone rubber foam layer.

[0056] In an advantageous embodiment, the coating tool for use herein comprises a material selected from the group consisting of polymers, metals, composites, glass, and any combination or mixture thereof. More advantageously, the coating tool for use herein comprises a material selected from the group consisting of metals, particularly aluminum, stainless steel, and any combination thereof. Flexible coating tools for use herein are typically relatively thin, particularly having a downstream thickness in the range of 0.1 to 0.75 mm. Rigid coating tools for use herein are typically at least 1 mm, or even at least 3 mm, thick.

[0057] According to an exemplary embodiment of the present disclosure, the coating tool for use herein is selected from the group consisting of a coating knife, a coating blade, a coating roll, a coating roll blade, and any combination thereof.

[0058] In an advantageous embodiment, the coating tool for use herein is selected from the group of coating knives. It has been found in practice that the use of a coating tool in the form of a coating knife provides a more reproducible coating process and a better quality coating, which translates into a silicone rubber foam layer with advantageous properties.

[0059] Advantageously, the coating tool for use herein is selected from the group of coating knives and air knives.

[0060] According to another advantageous aspect, the cross-sectional profile of the bottom part of the longitudinal coating tool (in particular the coating knife) is designed to form a precursor layer and remove excess precursor. Typically, the cross-sectional profile of the bottom part, as presented by the laterally extending edge of the coating tool facing the substrate, is essentially planar, curved, concave or convex.

[0061] A coating tool suitable for use herein is described in co-pending European Patent Application No. 20160564.9 (Attorney Docket No. 82970EP002, in the name of 3M Innovative Properties Company).

[0062] According to an advantageous aspect of the present disclosure, the polymer foam layer of the present disclosure is obtained by a method in which the step of providing a curable, foamable precursor of polymer foam to the upstream side of a coating tool is performed immediately followed by the step of providing a second solid film and applying the second solid film along the upstream side of the coating tool, such that the first solid film and the second solid film are applied simultaneously with the formation of (adjacent) layers of polymer foam precursor.

[0063] According to another advantageous aspect of the present disclosure, the steps of foaming or allowing to foam the polymer foam precursor and curing or allowing to cure the layer of polymer foam precursor to form the polymer foam layer are performed simultaneously.

[0064] The solid film used herein as the first and second solid films is not particularly limited.Any solid film known in the art can be formally used in the context of the present disclosure.Based on the present disclosure, those skilled in the art can easily identify the solid film suitable for use herein.

[0065] According to one advantageous embodiment, the first solid film and / or the second solid film for use in the present disclosure are impermeable films, in particular impermeable flexible films. As used herein, the term "impermeable" is intended to refer to impermeability to liquids and gaseous compounds, in particular gaseous compounds.

[0066] According to another advantageous aspect of the present disclosure, the first solid film and / or the second solid film for use herein is selected from the group consisting of a polymer film, a metal film, a composite film, and any combination thereof.

[0067] In a more advantageous aspect of the present disclosure, the first solid film and / or the second solid film for use herein are selected from the group consisting of polymer films, in particular polymer films comprising a polymer material selected from the group consisting of thermoplastic polymers.

[0068] In a further advantageous aspect of the present disclosure, the first solid film and / or the second solid film for use herein is a polymer film, wherein the polymer material is selected from the group consisting of polyester, polyether, polyolefin, polyamide, polybenzimidazole, polycarbonate, polyethersulfone, polyoxymethylene, polyetherimide, polystyrene, polyvinyl chloride, and any mixture or combination thereof.

[0069] In a further advantageous embodiment of the present disclosure, the first solid film and / or the second solid film for use herein is a polymer film comprising a polymer material selected from the group consisting of polyester, polyolefin (particularly PP and PE), polyetherimide, and any mixture or combination thereof.

[0070] In a particularly advantageous embodiment, the first solid film and / or the second solid film for use in the present disclosure is a polymer film comprising a polymer material selected from the group consisting of polyesters, in particular polyethylene terephthalate.

[0071] According to an advantageous aspect of the present disclosure, the polymer foam layer of the present disclosure is obtained by a method in which a first solid film is applied to a bottom surface of the layer of polymer foam precursor and a second solid film is applied to a top (exposed) surface of the layer of polymer foam precursor.

[0072] In an exemplary embodiment of the present disclosure, the first solid film and / or the second solid film directly contact the adjacent polymer foam layer.

[0073] In another advantageous aspect of the present disclosure, the first (top) and second (opposing) major (bottom) surfaces of the polymer foam layer and / or the first and / or second solid film are free of any adhesion promoting compositions or treatments, and in particular are free of priming compositions, adhesive compositions, and physical surface treatments.

[0074] In another advantageous aspect of the present disclosure, the first (top) and second (opposing) major (bottom) surfaces of the polymer foam layer and / or the first and / or second solid films comprise an adhesion promoting composition or treatment, particularly a priming composition, an adhesive composition, and a physical surface treatment.

[0075] In yet another advantageous aspect of the present disclosure, no intermediate layer of any kind is provided between the first major (top) surface or the second (opposing) major (bottom) surface of the polymer foam layer and the first solid film and / or the second solid film.

[0076] In typical embodiments of the present disclosure, the first and second solid films conformably and smoothly contact the corresponding surfaces of the silicone rubber foam layer, thereby avoiding (or at least reducing) the entrapment of air between the solid films and the corresponding surfaces of the polymer foam layer.

[0077] According to one advantageous aspect, the polymer foam layer for use herein comprises gas cavities, in particular gaseous hydrogen cavities, air gas cavities, and any mixture thereof.

[0078] According to one advantageous embodiment, the polymer foam layer for use herein comprises gas cavities having an oblong shape in the layer thickness direction (i.e., in the direction perpendicular to the plane formed by the foam layer).

[0079] According to a more advantageous embodiment, the gas cavities that may be present in the silicone rubber foam layer have an elliptical shape that is elongated in the layer thickness direction.

[0080] Advantageously, furthermore, the gas cavity for use herein is not surrounded by any ceramic or polymer shell (other than the surrounding silicone polymer matrix).

[0081] In one particular embodiment, a gas cavity for use herein has an average size (in its largest dimension) of 500 micrometers or less, 400 micrometers or less, 300 micrometers or less, 200 micrometers or less, 150 micrometers or less, 120 micrometers or less, 100 micrometers or less, 80 micrometers or less, 60 micrometers or less, 50 micrometers or less, 40 micrometers or less, 30 micrometers or less, or even more than 20 micrometers (as calculated from an SEM micrograph).

[0082] In another particular embodiment, the gas cavities for use herein have an average size (in the largest dimension) of 5 to 3000 micrometers, 5 to 2000 micrometers, 10 to 1500 micrometers, 20 to 1500 micrometers, 20 to 1000 micrometers, 20 to 800 micrometers, 20 to 600 micrometers, 20 to 500 micrometers, or even 20 to 400 micrometers (as calculated from SEM micrographs).

[0083] According to an exemplary embodiment, the polymer foam layer for use herein does not include hollow cavities (surrounded by an optional ceramic or polymer shell) selected from the group consisting of hollow microspheres, glass bubbles, expandable microspheres, particularly hydrocarbon-filled expandable microspheres, hollow inorganic particles, expanded inorganic particles, and any combination or mixture thereof.

[0084] According to an advantageous embodiment, the polymer foam layer for use herein comprises a non-syntactic foam.

[0085] The polymer foam layer of the present disclosure may include additional (optional) ingredients or additives depending on the intended application.

[0086] In certain aspects of the present disclosure, the polymer foam layers for use herein further comprise additives particularly selected from the group consisting of flame retardants, softeners, curing agents, filler materials, tackifiers, nucleating agents, colorants, pigments, preservatives, rheology modifiers (particularly aluminum hydroxide, magnesium hydroxide, magnesium carbonate, huntite, hydromagnesite, huntite-hydromagnesite, nesquehonite, and calcium carbonate), UV stabilizers, thixotropic agents, surface additives, flow additives, nanoparticles, antioxidants, reinforcing agents, toughening agents, silica particles, glass or synthetic fibers, thermal insulating particles, conductive particles, electrically insulating particles, infrared shielding particles, and any combination or mixture thereof.

[0087] In one advantageous aspect, the polymer foam layer further comprises a non-combustible (or non-burning) filler material. In a more advantageous aspect, the non-combustible filler material for use herein is selected from the group of inorganic fibers, in particular from the group consisting of mineral fibers, mineral wool, silicate fibers, ceramic fibers, glass fibers, carbon fibers, graphite fibers, asbestos fibers, aramid fibers, and any combination or mixture thereof.

[0088] According to a more advantageous aspect, the non-combustible filler material for use herein is selected from the group consisting of mineral fibers, silicate fibers, ceramic fibers, asbestos fibers, aramid fibers, and any combination or mixture.

[0089] According to a particularly advantageous embodiment, the non-combustible filler material for use herein is selected from the group consisting of mineral fibers. In the context of the present disclosure, it has surprisingly been discovered that polymer foams (particularly silicone rubber foams) further comprising mineral fibers exhibit excellent heat resistance and thermal stability properties and improved resistance to surface cracking and surface brittleness, even after prolonged exposure to temperatures up to 600°C. Without being bound by theory, these advantageous characteristics are believed to be due in particular to the excellent compatibility of the mineral fibers (particularly silicate fibers) with the surrounding polymer matrix (particularly silicone polymer matrix), which is responsible for densifying and mechanically stabilizing the resulting matrix.

[0090] In particular embodiments of this implementation, the non-combustible filler material for use herein is included in the polymer foam in an amount ranging from 0.5 to 40 wt%, 1 to 30 wt%, 1 to 20 wt%, 1 to 10 wt%, 1 to 8 wt%, 2 to 8 wt%, 2 to 6 wt%, or even 3 to 6 wt%, based on the total weight of the precursor composition of the polymer foam.

[0091] In another exemplary embodiment, the polymer foam layers for use herein do not include thermally conductive fillers.

[0092] According to one advantageous aspect of the present disclosure, the polymer foam layer for use herein has a compressive strength of 500 kg / m2, as measured according to the method described in the experimental section. 3 Below 450kg / m 3 Below 400kg / m 3 Below 380kg / m 3 Below 350kg / m 3 Below 320kg / m 3 Below 300kg / m 3 Below 280kg / m 3Below 250kg / m 3 Below 220kg / m 3 or less, or even 200 kg / m 3 It has the following density:

[0093] According to another advantageous aspect of the present disclosure, the polymer foam layer for use herein has a compressive strength of 200 to 500 kg / m, as measured according to the method described in the experimental section. 3 , 200~450kg / m 3 , 200~400kg / m 3 , 200~380kg / m 3 , 200~350kg / m 3 , 200~320kg / m 3 , 200-300kg / m 3 , 200~280kg / m 3 , or even 200 to 250 kg / m 3 It has a density in the range of

[0094] According to yet another advantageous aspect of the present disclosure, the polymer foam layers for use herein have a hardness (Shore 00) of greater than 10, greater than 15, greater than 20, greater than 25, greater than 30, greater than 40, or even greater than 50.

[0095] According to yet another advantageous aspect of the present disclosure, the polymer foam layer for use herein has a hardness (Shore 00) in the range of 10-80, 10-70, 20-70, 25-60, 25-55, 30-55, 30-50, 30-45, or even 30-40.

[0096] According to yet another advantageous aspect of the present disclosure, the polymer foam layers for use herein have a heat transfer time to 150°C of greater than 20 seconds, greater than 40 seconds, greater than 60 seconds, greater than 80 seconds, greater than 100 seconds, greater than 120 seconds, greater than 140 seconds, greater than 150 seconds, greater than 160 seconds, greater than 170 seconds, or even greater than 180 seconds, as measured according to Thermal Insulation Test Method 1 described in the Experimental Section.

[0097] According to yet another advantageous aspect of the present disclosure, the polymer foam layer for use herein has a heat transfer time to 150°C in the range of 20 to 200 seconds, 40 to 200 seconds, 60 to 200 seconds, 100 to 200 seconds, 120 to 200 seconds, 140 to 200 seconds, 160 to 200 seconds, or even 160 to 180 seconds, as measured according to Thermal Insulation Test Method 1 described in the Experimental Section.

[0098] According to yet another advantageous aspect of the present disclosure, a neat polymer foam layer for use herein has a thermal conductivity of 1 W / m·K or less, 0.8 W / m·K or less, 0.6 W / m·K or less, 0.5 W / m·K or less, 0.4 W / m·K or less, 0.3 W / m·K or less, 0.2 W / m·K or less, 0.1 W / m·K or less, 0.05 W / m·K or less, or even 0.01 W / m·K or less, when measured according to the test methods described in the Experimental Section.

[0099] According to yet another advantageous aspect of the present disclosure, the neat polymer foam layer for use herein has a thermal conductivity in the range of 0.01 to 1 W / m·K, 0.05 to 1 W / m·K, 0.1 to 1 W / m·K, 0.2 to 1 W / m·K, or even 0.2 to 0.8 W / m·K, when measured according to the test methods described in the Experimental Section.

[0100] According to yet another advantageous aspect of the present disclosure, the polymer foam layers for use herein are subjected to a ceramming process at a temperature of 600°C or less, 550°C or less, 500°C or less, 450°C or less, 400°C or less, 350°C or less, 300°C or less, or even 250°C or less.

[0101] According to yet another advantageous aspect of the present disclosure, the polymer foam layers for use herein are subjected to a ceramization process at temperatures ranging from 200°C to 600°C, 200°C to 550°C, 200°C to 500°C, 200°C to 450°C, 200°C to 400°C, 200°C to 350°C, 250°C to 350°C, or even 250°C to 300°C.

[0102] In the context of the present disclosure, it has been discovered, quite surprisingly, that polymer foam layers having the ability to undergo a ceramization process, particularly at relatively low temperatures, provide excellent heat resistance and thermal stability properties.

[0103] According to yet another advantageous aspect of the present disclosure, the polymer foam layers for use herein have a V-0 classification when measured according to the UL-94 standard flammability test method.

[0104] In an advantageous embodiment, the polymer foam layer for use herein has a thickness of 10,000 micrometers or less, 8,000 micrometers or less, 6,000 micrometers or less, 5,000 micrometers or less, 4,000 micrometers or less, 3,000 micrometers or less, 2,500 micrometers or less, 2,000 micrometers or less, or even 1,500 micrometers or less.

[0105] In another advantageous embodiment, the polymer foam layer for use herein has a thickness in the range of 100 to 10,000 micrometers, 100 to 8,000 micrometers, 100 to 6,000 micrometers, 200 to 5,000 micrometers, 300 to 5,000 micrometers, 300 to 4,500 micrometers, 300 to 4,000 micrometers, 500 to 4,000 micrometers, 500 to 3,000 micrometers, 500 to 2,500 micrometers, 500 to 2,000 micrometers, 500 to 1,500 micrometers, 800 to 1,500 micrometers, or even 1,000 to 1,500 micrometers.

[0106] According to one particular aspect of the present disclosure, a polymer foam layer for use herein may comprise a first solid film and / or a second solid film. In alternative implementations, the polymer foam layer may not comprise either a first solid film or a second solid film.

[0107] As will be apparent to one skilled in the art, the polymer foam layers for use herein may take on a variety of forms, shapes, and sizes depending on the intended application. Likewise, the polymer foam layers for use herein may be post-processed or converted as is conventional practice in the art.

[0108] According to one exemplary embodiment, the polymer foam layer for use herein may be in the form of a roll wound, particularly horizontally wound, around a core, with or without a first solid film and / or a second solid film.

[0109] According to one exemplary embodiment, the polymer foam layers for use herein may be cut into smaller pieces of various forms, shapes, and sizes.

[0110] At least one spacer layer for use in the multilayer structure of the present disclosure comprises a plurality of spacer elements, each spacer element having a protruding portion and two opposing end portions, and at least one end portion of each spacer element is completely embedded within the polymer foam layer.

[0111] The spacer layer for use herein is not particularly limited, so long as it comprises a plurality of spacer elements, each spacer element comprising a protruding portion and two opposing end portions. Suitable spacer layers for use herein can be readily identified by those skilled in the art in light of this disclosure.

[0112] One exemplary spacer layer for use herein is shown schematically in Figure 5. Figure 5 is a cross-sectional view of a multi-layer structure 16 according to one exemplary embodiment of the present disclosure, with one spacer layer 13, also shown in cross-section, disposed on one major surface of a polymer foam layer 4. The illustrated spacer layer 13 comprises a base layer 14 and a plurality of spacer elements 15, each spacer element 15 comprising a protruding portion 15c and two opposing end portions 15a and 15b.

[0113] According to one advantageous aspect of the present disclosure, the two opposing end portions of each spacer element are completely embedded within the polymer foam layer.

[0114] According to another advantageous aspect of the present disclosure, at least a portion of the protruding portion of each spacer element is completely embedded within the polymer foam layer.

[0115] According to a more advantageous aspect, the projecting portion of each spacer element is completely embedded in the polymer foam layer.

[0116] In another advantageous aspect of the present disclosure, the spacer elements of a spacer layer for use herein are positioned adjacent to and in direct contact with the polymer foam layer such that 0-100%, 10-100%, 30-100%, 50-100%, 70-100%, 90-100%, 95-100%, or even 100% of the spacer elements are fully embedded within the polymer foam layer.

[0117] In yet another advantageous aspect of the present disclosure, the spacer elements are equally spaced from one another within the spacer layer.

[0118] In yet another advantageous aspect, the spacer elements for use herein are unequally spaced from one another within the spacer layer.

[0119] In yet another advantageous aspect, the spacer elements for use herein are homogeneously or uniformly disposed within the spacer layer.

[0120] In yet another advantageous aspect, the spacer elements for use herein are non-homogeneously or unevenly disposed within the spacer layer.

[0121] According to another advantageous aspect of the present disclosure, the spacer elements for use herein have a uniform shape and / or size.

[0122] According to another alternative advantageous aspect of the present disclosure, spacer elements for use herein have non-uniform shapes and / or sizes.

[0123] In one exemplary aspect of the present disclosure, spacer elements for use herein have an overall shape (when viewed from a top view) selected from the group consisting of: circular, semicircular, oval, square, triangular, rectangular, diamond, polygonal, linear stripes, non-linear stripes, curved stripes, C-shaped stripes, S-shaped stripes, and any combination thereof.

[0124] In another exemplary embodiment, the spacer elements for use in the multi-layer structure have an overall shape (as viewed from a cross-sectional side view) selected from the group consisting of a cylinder, a pyramid, a cone, a sphere, a hemisphere, a barrel, a rod, a stick, a bar, a pole, and any combination thereof.

[0125] In another exemplary aspect of the present disclosure, a plurality of spacer elements for use herein form a patterned structure (or pattern) on the spacer layer (when viewed from a top view of the spacer layer), and the plurality of (individual) spacer elements are not specifically interconnected.

[0126] In yet another exemplary aspect of the present disclosure, a plurality of spacer elements for use herein form a patterned structure (or pattern) on the spacer layer (when viewed from a top view of the spacer layer), and the plurality of spacer elements are particularly interconnected.

[0127] In one advantageous aspect, the plurality of spacer elements form a patterned structure (or pattern) selected from the group consisting of a grid pattern, a diamond pattern, a honeycomb pattern, a pattern including parallel extending straight or wavy lines, a checkerboard pattern, a brick pattern, and any combination thereof.

[0128] According to one advantage of the present disclosure, the spacer elements for use herein have an overall shape (when viewed from a cross-sectional side view) selected from the group consisting of: cylindrical, pyramidal, conical, and any combination thereof. More advantageously, the spacer elements have an overall shape (when viewed from a cross-sectional side view) selected to be cylindrical.

[0129] According to another advantage of the present disclosure, the spacer elements for use herein have an overall shape (as viewed from a cross-sectional side view) selected to be cylindrical, with each cylindrical spacer element having an average diameter in the range of 100 to 5000 micrometers, 300 to 5000 micrometers, 500 to 5000 micrometers, 1000 to 5000 micrometers, or even 1000 to 4000 micrometers.

[0130] According to another advantage of the present disclosure, the spacer elements for use herein have an overall shape (as viewed from a cross-sectional side view) selected to be cylindrical, with the average height of each cylindrical spacer element ranging from 100 to 5000 micrometers, 100 to 4000 micrometers, 100 to 3000 micrometers, 200 to 3000 micrometers, 500 to 3000 micrometers, 500 to 2000 micrometers, 500 to 1500 micrometers, 800 to 1500 micrometers, or even 1000 to 1500 micrometers.

[0131] In an exemplary embodiment, a spacer layer for use in the present disclosure further comprises a base layer, with a plurality of spacer elements extending (or protruding) from the base layer.

[0132] In one advantageous aspect, the base layer for use herein comprises (is made from) the same material as the spacer elements.

[0133] In another advantageous aspect, a base layer for use herein comprises (is made from) a different material than the spacer elements.

[0134] In one exemplary embodiment of a multi-layer structure according to the present disclosure, each of the spacer elements is an integral part of the base layer.

[0135] In an exemplary embodiment, the base layer for use herein has a thickness in the range of 20 to 1000 micrometers, 20 to 800 micrometers, 40 to 800 micrometers, 40 to 600 micrometers, 50 to 600 micrometers, 50 to 500 micrometers, 50 to 400 micrometers, 100 to 400 micrometers, or even 100 to 300 micrometers.

[0136] In one particular aspect of the present disclosure, the base layer for use herein comprises openings and / or slits.

[0137] Further exemplary spacer layers for use herein are shown generally in Figures 7A-7D, which are top views of a suitable spacer layer 13 for use in the present disclosure. In Figures 7A-7D, spacer elements 15 of various shapes, sizes, and arrangements are shown protruding from a base layer 14. Figure 8 shows a perspective view of a spacer layer 13 according to one exemplary embodiment of the present disclosure.

[0138] In the context of the present disclosure, it has surprisingly been found that by varying the shape, size, and arrangement of the spacer elements on the spacer layer, different compression characteristics can be achieved for the corresponding multilayer structure, which then translates into different thermal insulation and thermal runaway barrier performance. This property provides excellent structural and design flexibility for the spacer layer, which translates into a remarkable ability to fine-tune the compression characteristics of the multilayer structure to specific applications, operating conditions, and battery cell types. It has been found that the main factors affecting the compression characteristics of a multilayer structure include the shape, size, and arrangement of the spacer elements on the spacer layer, particularly the distance between the spacer elements, the height of individual spacer elements, the particular pattern formed on the spacer layer by multiple spacer elements, and the materials used to form the spacer layer and spacer elements.

[0139] According to exemplary embodiments, a spacer layer for use in the multilayer structures of the present disclosure comprises (or is made of) a material selected from the group consisting of an elastomeric material, a thermoplastic material, a thermoplastic elastomeric material, a thermoplastic non-elastomeric material, a thermoset material, and any combination or mixture thereof.

[0140] In one advantageous aspect, the spacer layer for use herein comprises (or is made of) a material selected from the group consisting of silicone elastomers, fluorosilicone rubbers, aromatic polyamides, polybenzimidazoles, polysulfides, polyimides, polysulfones, polyetherketones, fluorocarbons, polyisoprene, polybutadiene, polychloroprene, polyurethanes, polyolefins (in particular PE, PP, EVA), polystyrene, and any combination or mixture thereof.

[0141] More advantageously, the spacer layer for use herein comprises (or is made from) a material selected from the group consisting of elastomeric materials.

[0142] In another more advantageous aspect, the spacer layer for use herein comprises a material selected from the group consisting of silicone elastomers, particularly silicone rubbers, and more particularly organopolysiloxane polymers.

[0143] In one particularly advantageous aspect of the present disclosure, the spacer layer for use herein is a silicone rubber layer.

[0144] In certain aspects of the present disclosure, the spacer layer for use herein further comprises additives particularly selected from the group consisting of flame retardants, softeners, hardeners, filler materials, tackifiers, nucleating agents, colorants, pigments, preservatives, rheology modifiers (particularly aluminum hydroxide, magnesium hydroxide, magnesium carbonate, huntite, hydromagnesite, huntite-hydromagnesite, nesquehonite, and calcium carbonate), UV stabilizers, thixotropic agents, surface additives, flow additives, nanoparticles, antioxidants, reinforcing agents, toughening agents, silica particles, glass or synthetic fibers, thermal insulating particles, conductive particles, electrically insulating particles, infrared shielding particles, and any combination or mixture thereof.

[0145] In one advantageous aspect, the spacer layer further comprises a non-combustible (or non-burning) filler material. In a more advantageous aspect, the non-combustible filler material for use herein is selected from the group of inorganic fibers, in particular from the group consisting of mineral fibers, mineral wool, silicate fibers, ceramic fibers, glass fibers, carbon fibers, graphite fibers, asbestos fibers, aramid fibers, and any combination or mixture thereof.

[0146] Spacer layers for use herein can be obtained by techniques commonly known in the art of structured polymer layers. Suitable techniques for obtaining spacer layers for use herein can be readily identified by those skilled in the art in light of this disclosure.

[0147] According to one advantageous aspect, the spacer layer for use herein is obtained by a technique selected from the group consisting of (micro)replication techniques (in particular using (micro)structured molded plates), embossing techniques (in particular using rotary bars with embedded structures), and any combination thereof.

[0148] In one beneficial aspect of the present disclosure, at least one spacer layer is disposed adjacent to and in direct contact with the polymer foam layer.

[0149] In another advantageous aspect of the present disclosure, at least one spacer layer is disposed adjacent to but not in direct contact with the polymer foam layer. According to this particular aspect of the present disclosure, at least one additional layer may be disposed adjacent to and in direct contact with the polymer foam layer, with the at least one additional layer being disposed between the polymer foam layer and the spacer layer. In one exemplary aspect, the at least one additional layer is selected from the group consisting of an adhesive layer, a tie layer, a primer layer, an adhesion-promoting layer, and any combination thereof.

[0150] According to one particular aspect of the multilayer structure, a polymer foam layer for use herein comprises a first major surface and a second major surface opposite the first major surface, and at least one spacer layer is provided on either the first major surface or the second major surface of the polymer foam layer.

[0151] According to another particular aspect of the multilayer structure, a polymer foam layer for use herein comprises a first major surface and a second major surface opposite the first major surface, wherein a first spacer layer is provided on the first major surface of the polymer foam layer and a second spacer layer is provided on the second major surface of the polymer foam layer.

[0152] In one particular aspect, the first spacer layer and the second spacer layer for use herein are the same. In another particular aspect, the first spacer layer and the second spacer layer for use herein are not the same.

[0153] In one particular embodiment of a multi-layer structure comprising two spacer layers, the first spacer layer and / or the second spacer layer is disposed adjacent to and in direct contact with the polymer foam layer.

[0154] FIG. 6 is a cross-sectional view of a multi-layer structure 16 according to one exemplary embodiment of the present disclosure, in which a first spacer layer 13, also shown in cross-section, is provided on a first major surface of a polymer foam layer 4, and a second spacer layer 17 is provided on a second major surface of the polymer foam layer 4.

[0155] In another specific embodiment of the multilayer structure comprising two spacer layers, the first spacer layer and / or the second spacer layer are disposed adjacent to but not in direct contact with the polymer foam layer. According to this specific embodiment of the present disclosure, at least one additional layer may be disposed adjacent to and in direct contact with the polymer foam layer, with the at least one additional layer being disposed between the polymer foam layer and the first spacer layer and / or the second spacer layer. In one exemplary embodiment, the at least one additional layer is selected from the group consisting of an adhesive layer, a tie layer, a primer layer, an adhesion-promoting layer, and any combination thereof.

[0156] According to one particular embodiment, at least one spacer layer for use herein is fully embedded within the polymer foam layer.

[0157] According to another particular aspect of the multilayer structure of the present disclosure, the spacer layer comprises a base layer having a first major surface and a second major surface opposite the first major surface, wherein the first plurality of spacer elements extend (or protrude) from the first major surface of the base layer and the second plurality of spacer elements extend (or protrude) from the second major surface of the base layer. According to this particular aspect of the present disclosure, the first plurality of spacer elements and the second plurality of spacer elements may or may not be identical.

[0158] According to yet another specific aspect of the multilayer structure, the spacer layer comprises a base layer having a first major surface and a second major surface opposite the first major surface, and the plurality of spacer elements extend (or protrude) from only the first major surface of the base layer, thereby eliminating the spacer elements from the second major surface of the base layer. According to this specific aspect of the present disclosure, at least one additional layer can be disposed adjacent to and in direct contact with the second major surface of the base layer. In one exemplary aspect, the at least one additional layer is selected from the group consisting of a metal layer, a polymer layer, a composite layer, and any combination thereof.

[0159] According to an exemplary embodiment, the multilayer structure of the present disclosure is a cushioning structure, in particular a multilayer (spacer) structure suitable for cushioning at least one expanding (and / or contracting) surface.

[0160] These expanding and / or contracting surfaces may typically be found in rechargeable electrical energy storage systems, particularly along the sidewalls of battery modules, and more particularly, battery cells.

[0161] In one particular aspect of the present disclosure, the at least one expanding and / or contracting surface expands (and / or contracts) when exposed to thermal energy (heat).

[0162] According to an advantageous embodiment, the multilayer structure of the present disclosure has a heat transfer time to 150°C of greater than 20 seconds, greater than 60 seconds, greater than 100 seconds, greater than 150 seconds, greater than 180 seconds, greater than 200 seconds, greater than 240 seconds, greater than 280 seconds, greater than 300 seconds, greater than 320 seconds, greater than 340 seconds, greater than 350 seconds, or even greater than 360 seconds, when measured at 0.1 MPa according to Thermal Insulation Test Method 2 described in the Experimental Section.

[0163] According to another advantageous aspect of the present disclosure, the multilayer structure has a heat transfer time to 150°C in the range of 20 to 380 seconds, 40 to 380 seconds, 60 to 380 seconds, 100 to 380 seconds, 150 to 380 seconds, 180 to 380 seconds, 200 to 380 seconds, 250 to 380 seconds, or even 300 to 380 seconds, measured at 0.1 MPa according to Thermal Insulation Test Method 2 described in the Experimental Section.

[0164] According to yet another advantageous aspect of the present disclosure, the multilayer structure has a heat transfer time to 150°C of greater than 20 seconds, greater than 40 seconds, greater than 60 seconds, greater than 80 seconds, greater than 100 seconds, greater than 120 seconds, greater than 140 seconds, greater than 150 seconds, greater than 160 seconds, greater than 170 seconds, or even greater than 180 seconds when measured at 1 MPa according to Thermal Insulation Test Method 2 described in the Experimental Section.

[0165] According to yet another advantageous aspect, the multilayer structures of the present disclosure have a heat transfer time to 150°C in the range of 20 to 200 seconds, 40 to 200 seconds, 60 to 200 seconds, 100 to 200 seconds, 120 to 200 seconds, 140 to 200 seconds, 160 to 200 seconds, or even 160 to 180 seconds, when measured at 1 MPa according to Test Method 2 described in the Experimental Section.

[0166] According to yet another advantageous aspect, the cushioning articles of the present disclosure have a thermal conductivity of 1 W / m·K or less, 0.8 W / m·K or less, 0.6 W / m·K or less, 0.5 W / m·K or less, 0.4 W / m·K or less, 0.3 W / m·K or less, 0.2 W / m·K or less, 0.1 W / m·K or less, 0.05 W / m·K or less, or even 0.01 W / m·K or less, when measured according to the test methods described in the Experimental Section.

[0167] In yet another advantageous aspect, the cushioning articles of the present disclosure have a thermal conductivity in the range of 0.01 to 1 W / m·K, 0.05 to 1 W / m·K, 0.1 to 1 W / m·K, 0.2 to 1 W / m·K, or even 0.2 to 0.8 W / m·K, when measured according to the test methods described in the Experimental Section.

[0168] In yet another advantageous aspect, the multi-layer structure of the present disclosure has a V-0 classification when measured according to the UL-94 standard flammability test method.

[0169] According to exemplary embodiments of the present disclosure, the multilayer structure has a thickness in the range of 100 to 10,000 micrometers, 100 to 8,000 micrometers, 100 to 6,000 micrometers, 200 to 5,000 micrometers, 300 to 5,000 micrometers, 300 to 4,500 micrometers, 300 to 4,000 micrometers, 500 to 4,000 micrometers, 500 to 3,000 micrometers, 500 to 2,500 micrometers, 500 to 2,000 micrometers, 500 to 1,500 micrometers, 800 to 1,500 micrometers, or even 1,000 to 1,500 micrometers.

[0170] According to another aspect, the present disclosure relates to the spacer layer described above.

[0171] In one advantageous aspect of the present disclosure, the spacer layer is suitable for use in a multi-layer cushioning structure, in particular a multi-layer (spacer) structure suitable for cushioning at least one expanding (and / or contracting) surface. According to one particular aspect of this implementation, the at least one expanding (and / or contracting) surface for use herein expands (and / or contracts) when exposed to thermal energy (heat).

[0172] According to another aspect, the present disclosure relates to a method for manufacturing the multilayer structure described above, comprising the steps of providing a polymer foam layer described above, providing at least one spacer layer described above, and applying the at least one spacer layer onto the polymer foam layer.

[0173] In one advantageous embodiment of the method, the step of applying at least one spacer layer onto the polymer foam layer is carried out by lamination.

[0174] In one particular aspect, the method includes laminating a first spacer layer onto a first major surface of the polymer foam layer and laminating a second spacer layer onto a second major surface of the polymer foam layer.

[0175] According to yet another aspect, the present disclosure is directed to a method for producing the multi-layer structure described above, the method comprising: a) providing a substrate; b) providing a solid film and applying it onto a substrate; c) providing a coating tool having an upstream side and a downstream side, the coating tool being offset from the substrate to form a gap perpendicular to the surface of the substrate; d) moving the solid film downstream relative to the coating tool; e) providing a curable (and foamable) precursor of a polymer foam to the upstream side of the coating tool, thereby coating the precursor of the polymer foam as a layer through the gap onto the substrate with a solid film; f) providing a spacer layer and applying it (at least partially) onto the (adjacent) layer of precursor of polymer foam; g) foaming or allowing the polymer foam precursor to foam; h) curing or allowing to cure the layer of polymer foam precursor, thereby forming a polymer foam layer; i) optionally subjecting the layer of polymer foam precursor to a heat treatment; j) optionally removing the solid film from the polymer foam layer.

[0176] In one advantageous aspect of this method, the spacer layer for use herein is applied (at least partially) along the upstream side of the coating tool, so that the solid film and the spacer layer are applied simultaneously with the formation of the (adjacent) layer of polymer foam precursor.

[0177] A schematic diagram of this exemplary method of producing a multilayer structure and an exemplary coating apparatus is shown in Figure 2. An exemplary coating apparatus for use in this method is very similar to the coating apparatus 1 described in Figure 1, except that the second solid film 6 is replaced by a spacer layer 13.

[0178] In a typical embodiment of this exemplary method, a curable, foamable precursor of polymer foam 3 is provided to the upstream side of a coating tool 7, thereby coating the polymer foam precursor 3 through the gap as a layer onto a substrate 2 with a first solid film 5. A spacer layer 13 comprising a base layer 14 with a plurality of spacer elements 15 is applied (at least partially) along the upstream side of the coating tool 7, such that the first solid film 5 and spacer layer 13 are applied simultaneously with the formation of the layer of polymer foam precursor 3.

[0179] The layer of polymer foam precursor 3 is then foamed and cured to provide polymer foam layer 4, which is typically provided with a first solid film 5 on its bottom surface and a spacer layer 13 on its top surface. Optionally, the layer of polymer foam precursor 3 may be subjected to a heat treatment, typically in an oven (not shown). After treatment, first solid film 5 can be removed from polymer foam layer 4, thereby providing multi-layer structure 16.

[0180] In another advantageous aspect of the method, the spacer layer for use herein is applied onto the (adjacent) layer of polymer foam precursor, (during or) after the formation of the (adjacent) layer of polymer foam precursor, in particular before the step of curing or allowing to cure the layer of polymer foam precursor.

[0181] A schematic diagram of this exemplary method of producing a multilayer structure and an exemplary coating apparatus is shown in Figure 4. An exemplary coating apparatus for use in this method is similar to the coating apparatus 1 described in Figure 2, except that the spacer layer 13 is not applied (at least partially) along the upstream side of the coating tool 7, but rather via an additional coating roll present in the downstream portion of the coating apparatus 1.

[0182] In a typical embodiment of this exemplary method, a curable, foamable precursor of polymer foam 3 is provided upstream of a coating tool 7, which coats the polymer foam precursor 3 as a layer through the gap onto the substrate 2 with the first solid film 5. The polymer foam precursor 3 is then allowed to foam. A spacer layer 13 comprising a base layer 14 with a plurality of spacer elements 15 is then applied (at least partially) after the formation of the (adjacent) layer of polymer foam precursor 3.

[0183] The layer of polymer foam precursor 3 is then cured to provide polymer foam layer 4, which is typically provided with a first solid film 5 on its bottom surface and a spacer layer 13 on its top surface. Optionally, the layer of polymer foam precursor 3 may be subjected to a heat treatment, typically in an oven (not shown). After processing, the first solid film 5 may be removed from polymer foam layer 4, thereby providing multi-layer structure 16.

[0184] In another advantageous aspect of the method, the spacer layer for use herein is applied onto the (adjacent) layer of polymer foam precursor after formation of the (adjacent) layer of polymer foam precursor, in particular after the step of curing or allowing to cure the layer of polymer foam precursor.

[0185] According to yet another aspect, the present disclosure is directed to a further method for producing the multi-layer structure described above, the method comprising: a) providing a substrate; b) providing a spacer layer and applying it onto the substrate; c) providing a coating tool having an upstream side and a downstream side, the coating tool being offset from the substrate to form a gap perpendicular to the surface of the substrate; d) moving the spacer layer downstream relative to the coating tool; e) providing a curable (foamable) precursor of a polymer foam to the upstream side of the coating tool, thereby coating the precursor of the polymer foam as a layer through the gap onto the substrate with a solid film; f) providing a solid film and applying it (at least partially) onto the (adjacent) layer of precursor of polymer foam; g) foaming or allowing the polymer foam precursor to foam; h) curing or allowing to cure the layer of polymer foam precursor, thereby forming a polymer foam layer; i) optionally subjecting the layer of polymer foam precursor to a heat treatment; j) optionally removing the solid film from the polymer foam layer.

[0186] In one advantageous aspect of this method, the solid film is applied (at least partially) along the upstream side of the coating tool, so that the solid film and spacer layer are applied simultaneously with the formation of the (adjacent) layer of polymer foam precursor.

[0187] In another advantageous embodiment of the method, the solid film is replaced by a second spacer layer, in particular identical to or different from the first spacer layer.

[0188] A schematic diagram of this exemplary method of producing a multilayer structure and an exemplary coating apparatus is shown in Figure 3. An exemplary coating apparatus for use in this method is very similar to the coating apparatus 1 described in Figure 1, except that second solid film 6 is replaced by first spacer layer 13 and first solid film 5 is replaced by second spacer layer 17.

[0189] In a typical embodiment of this exemplary method, a curable, foamable precursor of polymer foam 3 is provided to an upstream side of a coating tool 7, thereby coating the polymer foam precursor 3 through the gap as a layer onto a substrate 2 with a second spacer layer 17. A first spacer layer 13 comprising a base layer 14 with a plurality of spacer elements 15 is applied (at least partially) along the upstream side of the coating tool 7, such that the second spacer layer 17 and the first spacer layer 13 are applied simultaneously with the formation of the layer of polymer foam precursor 3.

[0190] The layer of polymer foam precursor 3 is then foamed and cured to provide a polymer foam layer 4, which is typically provided with a second spacer layer 17 on its bottom surface and a first spacer layer 13 on its top surface, thereby providing a multi-layer structure 16. Optionally, the layer of polymer foam precursor 3 may be subjected to a heat treatment, typically in an oven (not shown).

[0191] In one advantageous aspect of these methods, the step of providing a curable (foamable) precursor of the polymer foam to the upstream side of the coating tool is carried out immediately before the step of providing a spacer layer or solid film and applying it along the upstream side of the coating tool.

[0192] In another advantageous aspect of the present disclosure, the steps of foaming or allowing to foam the polymer foam precursor and curing or allowing to cure the layer of polymer foam precursor, thereby forming the polymer foam layer, are performed simultaneously.

[0193] According to yet another aspect, the present disclosure is directed to a method for manufacturing the spacer layer described above, the method comprising: a) providing a substrate; b) providing a solid film and applying it onto a substrate; c) providing a coating tool having an upstream side and a downstream side, the coating tool being offset from the substrate to form a gap perpendicular to the surface of the substrate; d) moving the solid film downstream relative to the coating tool; e) providing a curable precursor of the spacer material to the upstream side of the coating tool, whereby the precursor of the spacer material is coated as a layer onto the substrate with a solid film through the gap; f) providing a structured (or patterned) solid film and applying it (at least partially) onto the (adjacent) layer of a precursor of the spacer material; g) curing or allowing to cure the layer of precursor of the spacer material, thereby forming a spacer layer; h) removing the structured (or patterned) solid film from the spacer layer; i) optionally subjecting the layer of precursor of the spacer material to a heat treatment; j) optionally removing the solid film from the spacer layer.

[0194] According to yet another aspect, the present disclosure is directed to a further method for fabricating the spacer layer described above, the method comprising: a) providing a substrate; b) providing a solid film and applying it onto a substrate; c) providing a rotary coating tool with a structured or embossed surface; d) moving the solid film downstream relative to the coating tool; e) providing a curable precursor of the spacer material directly onto the structured surface of the rotary coating tool, whereby the precursor of the spacer material is coated as a layer onto the substrate with a solid film through the gap, structuring or embossing the surface; f) curing or allowing to cure the layer of precursor of the spacer material, thereby forming a spacer layer; g) optionally heating the rotating coating tool; h) optionally subjecting the layer of precursor of the spacer material to a heat treatment; i) optionally removing the solid film from the spacer layer.

[0195] According to another aspect, the present disclosure is directed to a thermal barrier article comprising the multilayer structure described above.

[0196] According to yet another aspect, the present disclosure relates to a rechargeable electrical energy storage system, in particular a battery module, comprising the thermal (runaway) barrier article described above.

[0197] In yet another aspect, the present disclosure is directed to a battery module including a plurality of battery cells separated from one another by gaps, and the above-described multi-layer structure disposed in the gaps between the battery cells.

[0198] 9 illustrates an exemplary assembled battery module 18 according to one embodiment of the present disclosure, which includes a plurality of battery cells 19 separated from one another by gaps and a plurality of multi-layer structures 16 disposed in the gaps between the battery cells 19. The battery module further includes a base plate 21 having a thermally conductive gap filler 20 disposed thereon.

[0199] Suitable battery modules, cell subunits, and methods of manufacturing the same for use herein are described, for example, in EP 3352290(A1) (Goeb et al.), particularly Figures 1-3 and paragraphs

[0016] -

[0035] , the contents of which are incorporated herein by reference in their entirety.

[0200] According to an advantageous aspect of the battery module according to the present disclosure, the battery cells for use herein are selected from the group consisting of pouch-type energy storage cells and prismatic-type energy storage cells, in particular from the group of pouch-type energy storage cells.

[0201] According to another aspect, the present disclosure is directed to a method of manufacturing a battery module, the method including providing a plurality of battery cells separated from one another by gaps, and disposing the above-described multi-layer structure in the gaps between the battery cells.

[0202] According to yet another aspect, the present disclosure is directed to a method of cushioning at least one expanding (and / or contracting) surface, comprising applying the above-described multilayer structure to at least a portion of the at least one expanding (and / or contracting) surface. In one particular aspect, the at least one expanding and / or contracting surface expands (and / or contracts) when exposed to thermal energy (heat).

[0203] According to yet another aspect, the present disclosure relates to the use of the above multilayer structures for industrial applications, in particular for thermal management applications, more particularly in the transportation industry, and even more particularly in the automotive, aviation, and aerospace industries.

[0204] According to yet another aspect, the present disclosure relates to the use of the multilayer structure described above as a thermal barrier, in particular as a thermal runaway barrier.

[0205] In yet another aspect, the present disclosure relates to the use of the above-described multi-layer structure as a thermal barrier spacer, particularly a thermal runaway barrier spacer, in a rechargeable electrical energy storage system, particularly in a battery module.

[0206] In yet another aspect, the present disclosure relates to the use of the above-described multi-layer structure as a thermal barrier spacer, particularly a thermal runaway barrier spacer, between multiple battery cells present in a rechargeable electrical energy storage system, particularly a battery module.

[0207] In yet another aspect, the present disclosure relates to the use of the multi-layer structure as a cushioning spacer between multiple battery cells present in a rechargeable electrical energy storage system, particularly a battery module.

[0208] In yet another aspect, the present disclosure relates to the use of the above multilayer structure as a cushioning spacer for cushioning at least one expanding (and / or contracting) surface, in particular the at least one expanding (and / or contracting) surface upon exposure to thermal energy (heat). [Example]

[0209] The present disclosure is further illustrated by the following examples, which are for illustrative purposes only and are not intended to limit the scope of the appended claims.

[0210] Test Method 1) Thermal stability test The test was carried out in a muffle furnace at 600°C. Test specimens were cut from the sample sheets and placed in porcelain crucibles. The porcelain crucibles were then placed in the furnace at 600°C for 3 minutes, then removed and allowed to cool before being analyzed by microscopy. The weight loss (%) of the samples after 3 minutes at 600°C was calculated.

[0211] 2) Insulation test 1 The test was performed in compression mode using a ZwickRoell tensile / compression testing machine. The compression testing machine was equipped with two plates (dimensions: 65 x 80 x 20 mm W x L x H, made of Inconel® steel, with external insulation): a cold (23°C) bottom plate equipped with a thermocouple for recording temperature, and a top plate heated to a constant temperature of 600°C. At the start of the test, a heat shield was placed between the two plates. The sample was placed on the cold bottom plate, and the heat shield was removed. The top plate was moved to a 1000 micrometer gap between the two plates. The temperature rise of the cold plate was recorded over time. Specifically, the time it took for the cold plate to reach 150°C was recorded in seconds.

[0212] 3) Insulation test 2 This test was performed in compression mode using a ZwickRoell tensile / compression testing machine. The compression testing machine was equipped with two plates (dimensions: 65 x 80 x 20 mm W x L x H, made of Inconel® steel, externally insulated): a cold (23°C) bottom plate equipped with a thermocouple for recording temperature, and a top plate heated to a constant temperature of 600°C. At the start of the test, a heat shield was placed between the two plates. The sample was placed on the cold bottom plate, and the heat shield was removed. The top plate was moved toward the bottom plate until a specific counter pressure or compression force (0.1 MPa or 1 MPa) was reached. The pressure was maintained for the measurement time. The temperature rise of the cold plate was then recorded over time. Specifically, the time in seconds for the cold plate to reach 150°C was recorded.

[0213] 4) Thermal conductivity measurement The thermal conductivity of the cured compositions was measured using flash analysis in a Netzsch Hyperflash LFA467 (Netzsch, Selb, Germany) according to ASTM E1461 / DIN EN821 (2013). 1 mm thick samples were prepared by coating the curable composition between two PET release liners with a knife coater and curing at room temperature. The samples were then carefully cut into 10 mm x 10 mm squares using a knife cutter to fit the sample holder. Prior to measurement, both sides of the samples were coated with a thin layer of graphite (GRAPHIT33, Kontakt Chemie). For the measurements, a pulse of light (xenon flash lamp, 230 V, 20-30 microsecond duration) was irradiated onto the bottom side, and the temperature of the top side of the sample was measured using an InSb IR detector. The diffusivity was then calculated from the thermogram fitting using the Cowan method. Three measurements were performed for each sample at 23 °C. Three samples were prepared and measured for each formulation. Thermal conductivity was calculated from the thermal diffusivity, density, and specific heat capacity of each sample. Heat capacity (Cp) was calculated in joules per gram per kelvin using a Netzsch-LFA Hyper Flash in combination with a standard sample (Polyceram). Density (d) was measured in grams per cubic centimeter based on the sample's weight and geometric dimensions. Using these parameters, thermal conductivity (L) was calculated in watts per meter per kelvin according to L = a·d·Cp.

[0214] 5) Flammability test Testing was performed using the UL 94 standard, i.e., the Standard for Flammability Safety Testing of Plastic Materials for Equipment and Appliance Parts. UL 94 is a flammability standard for plastics published by Underwriters Laboratories, USA. This standard determines whether a material tends to extinguish or spread the flame when a test specimen ignites. The UL-94 standard is harmonized with IEC 60707, 60695-11-10, and 60695-11-20, and ISO 9772 and 9773. 75 mm x 150 mm specimens were exposed to a 2 cm, 50 W tirrel burner flame ignition source. The test specimen was positioned vertically above the flame, with the test flame hitting the bottom of the specimen. The time to extinguishment was measured for each specimen, and a V rating was assigned. As shown in Table 1 below, the V rating is a measure of the time it takes for the sample to extinguish without burning to the top of the clamp or dropping molten material that ignites the cotton indicator. [Table 1]

[0215] 6) Compression test Compression tests were performed in compression mode using a Zwick tensile tester. The samples had a diameter of 50.8 mm and a thickness of more than 1000 micrometers. Tests were performed at 23°C. The top plate of the compression tester was moved at a rate of 1 mm / min until a maximum force of 2 MPa was reached. The compression force (in kPa) required to reach a compression value of at least 60% was recorded.

[0216] 7) Coating weight The coating weight of the polymer foam layer was measured by cutting a 100 cm sample from the sample layer using a circle cutter. 2 The coating weight was then determined in g / m 2 was converted to.

[0217] 8) Thickness The thickness of the polymer foam layer was measured using a thickness gauge.

[0218] 9) Density Density of the polymer layer (g / m 3 unit) to the coating weight of the foam layer (g / m 2 The thickness was calculated by dividing the thickness (in m) of the

[0219] 10) SEM micrograph The polymer foam images were obtained from SEM micrographs recorded on a tabletop microscope TM3030 available from Hitachi High-Tech Corporation.

[0220] raw materials: In the examples, the following raw materials were used:

[0221] DOWSIL 3-8235 is a two-part room temperature vulcanizable silicone rubber foam formulation commercially available under the trade name DOWSIL obtained from Dow Chemical Company (Midland, MI, United States).

[0222] VTV750 is a two-component room temperature vulcanizing liquid silicone rubber with a Shore hardness of A40, available from Renishaw PLC, UK.

[0223] RN 50 / 50 is a PET solid film commercially available under the trade name HOSTAPHAN RN50 / 50 obtained from Mitsubishi Polyester Film (Greer, SC, United States).

[0224] Working Example: General homemade preparation method for exemplary polymer foam layers: An exemplary homemade polymer foam layer was prepared according to the following procedure.

[0225] DOWSIL 3-8235 Parts A and B were filled into a 200 mL two-component cartridge system manufactured by Adchem GmbH (Wendelstein, Bayern, Germany) at a volumetric mix ratio of 1:1 (200 ml F system cartridge). The two-component silicone system was mixed in a static mixer (MFH10-18T) using a dispensing gun at 4 bar air pressure. After 50 grams (g) of the mixed silicone was released into the jar, the mixture was further homogenized by hand for 10 seconds using a wooden spatula. The mixture was then coated between two layers of RN 50 / 50 solid film using a knife coater. The resulting sheet expanded, and the reaction was completed by placing the sheet in a blast oven at 80 ° C for 10 minutes.

[0226] Exemplary General Method for Continuous Preparation of Polymer Foam Layers: An exemplary continuously produced polymer foam layer was prepared according to the following procedure.

[0227] Parts A and B of DOWSIL 3-8235 were loaded into a unique cartridge system equipped with a dynamic mix head (3M 05846 Pneumatic Dynamic Mixing System available from 3M Company, St. Paul, MN, United States). The cartridge had a 1:1 volumetric mix ratio and a dynamic mixing nozzle adapted for the 1:1 system (3M 05847 Dynamic Mixing Nozzle also available from 3M). By applying a pressure of 400 kPa, the piston of the dispenser extruded the material through the nozzle, which rotated at 2000-3000 revolutions per minute (RPM). The throughput was 3.5 kg / h. The coating weight was 480 g / m². 2 A continuous bead of dynamically mixed material was applied between two layers of solid RN 50 / 50 solid film and extruded through a knife coater with a gap of 350 micrometers and a width of 18.5 cm, as depicted in Figure 1. The web speed was 0.7 m / min. The final foam thickness was 2150 micrometers.

[0228] General homemade preparation method for exemplary spacer layers: An exemplary homemade silicone rubber spacer layer was prepared according to the following procedure.

[0229] The A and B parts of VTV750 were premixed by hand in a 10:1 silicone to curing agent volumetric mix ratio, then transferred to a container and mixed in a Speedmixer at 3500 rpm for 10 seconds. The resulting composition was spread between a layer of solid RN 50 / 50 film and a perforated plate, and coated using a knife coater with a controlled gap of approximately 100 micrometers between the solid film and the perforated plate with multiple cylindrical perforations. The resulting spacer layer comprised a base layer having a thickness of approximately 100 micrometers and multiple cylindrical spacer elements (diameter: 4000 micrometers, height: 1200 micrometers) with a spacing of approximately 6000 micrometers between adjacent spacer elements, as shown schematically in FIG. 8.

[0230] General homemade preparation method for exemplary multilayer structures: An exemplary multi-layer structure was prepared by simply laminating the spacer layer onto the polymer foam layer so that the spacer layer was adjacent to and in direct contact with the polymer foam layer.

[0231] Exemplary Multilayer Structure (Example 1) and Comparative Example CE-1: Exemplary multilayer structures and comparative examples are shown in Table 2, and complementary processing parameters are identified. Comparative Example CE-1 is a neat polymer foam layer without any spacer layer. Thermal insulation performance testing (Test 2) was performed, and the results are shown in Tables 3 and 4. [Table 2]

[0232] Insulation performance (Test 2) [Table 3] [Table 4] In the following, exemplary embodiments are presented. [Item 1] A multilayer structure comprising: a) a polymer foam layer; b) at least one spacer layer comprising a plurality of spacer elements; wherein each spacer element has a protruding portion and two opposing end portions, and at least one end portion of each spacer element is completely embedded within the polymer foam layer. [Item 2] Item 10. The multilayer structure of item 1, wherein the polymer foam layer comprises a material having a weight loss of 70% or less after 3 minutes at 600°C, as measured according to the Thermal Stability Test Method described in the Experimental Section. [Item 3] 3. The multilayer structure of claim 1 or 2, wherein the polymer foam layer comprises a material selected from the group consisting of an elastomeric material, a thermoplastic material, a thermoplastic elastomeric material, a thermoplastic non-elastomeric material, a thermoset material, and any combination or mixture thereof. [Item 4] 4. The multilayer structure according to any one of items 1 to 3, wherein the polymer foam layer comprises a material selected from the group consisting of silicone elastomers, particularly silicone rubbers, and more particularly organopolysiloxane polymers. [Item 5] 5. The multilayer structure of any one of items 1 to 4, wherein the polymer foam layer reaches a compression value of at least 60% when using a compression force of 700 kPa or less, as measured according to the Compression Test Method described in the Experimental Section. [Item 6] 6. The multilayer structure of any one of items 1 to 5, wherein the protruding portion of each spacer element is completely embedded within the polymer foam layer. [Item 7] 7. The multilayer structure of any one of items 1 to 6, wherein the spacer elements have an overall shape selected from the group consisting of a circle, a semicircle, an oval, a square, a triangle, a rectangle, a diamond, a polygon, a linear stripe, a non-linear stripe, a curved stripe, a C-shaped stripe, an S-shaped stripe, and any combination thereof. [Item 8] 8. The multilayer structure of any one of items 1 to 7, wherein the plurality of spacer elements form a patterned structure on the spacer layer. [Item 9] 9. The multilayer structure of any one of items 1 to 8, wherein the spacer layer further comprises a base layer, and the plurality of spacer elements extend from the base layer. [Item 10] 10. The multilayer structure of any one of items 1 to 9, wherein the spacer layer comprises a material selected from the group consisting of an elastomeric material, a thermoplastic material, a thermoplastic elastomeric material, a thermoplastic non-elastomeric material, a thermosetting material, and any combination or mixture thereof. [Item 11] 11. The multilayer structure according to any one of items 1 to 10, wherein the spacer layer comprises a material selected from the group consisting of silicone elastomers, in particular silicone rubbers, more particularly organopolysiloxane polymers. [Item 12] 12. The multilayer structure according to any one of items 1 to 11, wherein the spacer layer is obtained by a technique selected from the group consisting of a high-definition surface technique, an embossing technique, and any combination thereof. [Item 13] A method for producing the multilayer structure according to any one of items 1 to 12, Providing a polymer foam layer according to any one of items 1 to 5; providing at least one spacer layer according to any one of items 1 to 12; applying the at least one spacer layer onto the polymer foam layer; A method comprising: [Item 14] 13. Use of the multilayer structure according to any one of items 1 to 12 for industrial applications, in particular for thermal management applications, more particularly in the transportation industry. [Item 15] 13. Use of the multilayer structure according to any one of items 1 to 12 as a thermal barrier, in particular a thermal runaway barrier, in a rechargeable electrical energy storage system, in particular in a battery module.

Claims

1. a) a polymer foam layer; b) at least one spacer layer comprising a plurality of spacer elements; each spacer element having a protruding portion and two opposing end portions, at least one end portion of each spacer element being completely embedded within the polymer foam layer, and the spacer layer comprising a silicone elastomer.

2. 10. The thermal barrier for a rechargeable electrical energy storage system of claim 1, wherein the polymer foam layer comprises a material having a weight loss of 70% or less after 3 minutes at 600°C when measured according to the Thermal Stability Test Method described in the Experimental Section.

3. 3. The thermal barrier for a rechargeable electrical energy storage system of claim 1 or 2, wherein the polymer foam layer comprises a material selected from the group consisting of an elastomeric material, a thermoplastic material, a thermoplastic elastomeric material, a thermoplastic non-elastomeric material, a thermoset material, and any combination or mixture thereof.

4. The thermal barrier for a rechargeable electrical energy storage system according to any one of claims 1 to 3, wherein the polymer foam layer comprises a silicone elastomer.

5. 5. A thermal barrier for a rechargeable electrical energy storage system according to any one of claims 1 to 4, wherein the polymer foam layer reaches a compression value of at least 60% when measured according to the Compression Test Method described in the Experimental Section using a compression force of 700 kPa or less.

6. A thermal barrier for a rechargeable electrical energy storage system according to any one of claims 1 to 5, wherein the protruding portion of each spacer element is fully embedded within the polymer foam layer.

7. The thermal barrier for a rechargeable electrical energy storage system of any one of claims 1 to 6, wherein the spacer layer further comprises a base layer, the plurality of spacer elements extending from the base layer.

8. A method for producing a thermal barrier for a rechargeable electrical energy storage system according to any one of claims 1 to 7, comprising the steps of: Providing a polymer foam layer according to any one of claims 1 to 5; Providing at least one spacer layer according to any one of claims 1 to 7; applying the at least one spacer layer onto the polymer foam layer; A manufacturing method comprising:

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