Silicone foam sealing article

Abstract

The present disclosure relates generally to the field of silicone foam articles, more specifically to the field of silicone foam articles having good compressibility and used as thermal barriers. In preferred embodiments, the article is a compressible thermally insulative silicone foam comprising fillers, and having differential burst pressures in the z (thickness) and xy directions. These compressible thermally insulative silicone foams can be used as venting sealants for enclosed environments. The present disclosure also relates to a method of manufacturing such articles and to their use for industrial applications, for example in electric vehicle battery systems.

Description

[0001] SILICONE FOAM SEALING ARTICLE

[0002] The present disclosure relates generally to the field of silicone foam articles, more specifically to the field of silicone foam articles having good compressibility and used as thermal barriers. In preferred embodiments, the article is a compressible thermally insulative silicone foam comprising fillers, and having differential burst pressures in the z (thickness) and xy directions. These compressible thermally insulative silicone foams can be used as venting sealants for enclosed environments. The present disclosure also relates to a method of manufacturing such articles and to their use for industrial applications, for example in electric vehicle battery systems.

[0003] Background

[0004] Automotive electrification is currently one of the biggest trends in the automotive industry. Within this trend, the propulsion of electric energy supplied by electric batteries and the development of suitable electric vehicle batteries as energy storage devices are the main focus in the automotive industry. Electric-vehicle batteries are used to power the propulsion system of battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs). These batteries, which are typically lithium-ion batteries, are designed with a high ampere hour capacity. The trend in the development of electric vehicle batteries is to increase the energy density in the battery (kWh / kg) to allow traveling longer distances and reducing charging times of the battery.

[0005] Due to the high energy density of electric vehicle batteries and the high energy flow during charging or discharging of the battery, there is a risk of creation of hot spots and thermal runaway events where the heat generated by the decomposition of battery cells propagates very rapidly to neighboring cells. This chain reaction usually results in a rapid temperature increase and the release of gases that are the product of reactions taking place among the different cell components at these high temperatures.

[0006] In that context, there is a need in the industry for thermal management solutions that can allow gases from an adverse event to selectively escape from battery assemblies to mitigate further thermal runaway events and / or temperature rise in neighboring cells.

[0007] Summary

[0008] In a general embodiment, the disclosure is directed to a thermally-insulating polymeric foam layer, comprising

[0009] • a silicone elastomer,

[0010] • one or more fillers wherein the silicone elastomer is a cured foamed polymer, wherein the polymeric foam layer has a width, a length, and a thickness, wherein the uncompressed polymeric foam layer has a burst pressure of less than 10 psi in the thickness direction (z-direction) under the z-Burst Test, wherein the polymeric foam layer has a burst pressure higher than 8Opsi in the xy direction for a compression ratio of 30% under the xy-Burst Test, wherein the one or more fdlers are inorganic; wherein the total amount of inorganic fillers is at least 35 wt% by weight with respect to the total weight of the polymeric foam layer.

[0011] Brief Description of the Drawings

[0012] FIG. 1 shows the cross section of a battery assembly comprising a thermally-insulating polymeric foam layer of the present disclosure.

[0013] FIG. 2 shows the cross section of a battery assembly comprising a thermally-insulating polymeric foam layer of the present disclosure bursting under pressure in the z-direction, but sealing and protecting neighboring cells in the xy-direction.

[0014] FIGs. 3A-C show a setup of the burst pressure test in z-direction. FIG. 3A shows a foam sheet is placed on lower metal plate with opening towards the pressure inlet. Shims are used to set the defined foam thickness in assembly. FIG. 3B shows an upper metal plate with burst opening is placed on top of the foam sheet. FIG. 3C shows a fully mounted test fixture including compressed air regulator.

[0015] FIGs. 4A-F show a set-up of the burst pressure test in x-y-direction. FIG. 4A shows a round piece of foam shield is placed on lower metal plate of x-y Burst test. FIG. 4B shows a metal plate is placed on top of foam shield to prevent air leakage in z-direction. FIG. 4C shows an example of foam shield bursting in x-y-direction. FIG. 4D shows a fully mounted test fixture in site view. FIG. 4E shows a fully mounted test fixture in top view. FIG. 4F shows a fully mounted test fixture including compressed air regulator.

[0016] FIG. 5 show the torch test fixture assembly with oversized foam sheet assembly from a top view.

[0017] FIG. 6 show the torch test fixture assembly with oversized foam sheet assembly from a side view.

[0018] FIG. 7 shows the torch test setup showing torch, thermocouple, and sample assembly.

[0019] FIG. 8 shows compression behavior of foam shield in dependence of applied force.

[0020] Detailed description

[0021] Battery cells within a battery module may be subject to adverse events during which the battery cell may discharge all of its stored energy in a matter of seconds. During this discharge, cell temperatures can reach a minimum of 400 °C with areas of localized discharge reaching temperatures of over 1200 °C. Without proper thermal management, the heat from the failing cell may be enough on its own to overheat neighboring battery cells. This overheating may cause those neighboring cells to fail in a similar fashion in an event referred to as thermal runaway.

[0022] During a thermal runaway event, the highest temperatures and abrasive wear may be experienced around vent ports within the cell (see Fig. 1) because they represents areas with a decreased resistance to gas flow that allows overheated gases to converge to that location. Typically, the vent port gives the runaway cell a controllable direction to discharge its pressure, heat, and debris during failure. Nonetheless, thermally stable, durable materials are still needed to protect the adjacent cells in a battery module during a thermal runaway event.

[0023] In this application, silicone-based foams with functional fillers, in particular thermally- insulating polymeric foam layers, are described for use as a venting sealant in automotive battery modules. The polymeric foam layers are intended to provide good compressibility and thermal insulation during normal use and controllably fail in one uncompressed direction (e.g., its thickness or z-direction) while providing a high degree of thermal insulation and structural support in the other xy- directions.

[0024] These polymeric foam layers allow for easier cell assembly over liquid sealants because they do not require application equipment. At the same time, these polymeric foam layers provide another barrier between neighboring battery cells and can be placed over venting ports, which experience the highest temperature and pressure during battery cell failure, so that the polymeric foam layer ruptures easily in the thickness direction and allows gases to escape without additional weakening of the material (such as slits, cuts, etc), reducing internal pressure within the cell and / or module.

[0025] FIG. 1 shows the cross section of a battery assembly (100) having a cell walls (101, thick outline) and a variety of battery cells (102(a), (102(b), and (103(c).) Each battery cell has at least one corresponding vent port (103). The diagram shows the location of a thermally-insulating polymeric foam layer (104) in contact (immediately adjacent) with the venting port(s) and adjacent the battery cell wall. It is possible, however, to place a thermally-insulating polymeric foam layer in indirect contact (adjacent) with a venting port.

[0026] FIG. 2 shows the same battery assembly as in FIG. 1 after cell 202(b) suffered an adverse event and hot gases (205) are being released through the venting port (203) and through the seal provided by the polymeric foam layer (204), which has ruptured in the thickness (z) direction, but which has maintained structural integrity in the xy plane, protecting neighboring cells 202(a) and 202(c).

[0027] According to a first aspect, the present disclosure relates to a thermally-insulating polymeric foam layer, comprising

[0028] • a silicone elastomer,

[0029] • one or more fillers wherein the silicone elastomer is a cured foamed polymer, wherein the polymeric foam layer has a width, a length, and a thickness, wherein the uncompressed polymeric foam layer has a burst pressure of less than 10 psi in the thickness direction (z-direction) under the z-Burst Test, wherein the polymeric foam layer has a burst pressure higher than 80psi in the xy direction for a compression ratio of 30% under the xy-Burst Test, wherein the one or more fillers are inorganic; wherein the total amount of inorganic fillers is at least 35 wt% by weight with respect to the total weight of the polymeric foam layer.

[0030] In the context of the present disclosure, the inventors surprisingly found that a thermally- insulating polymeric foam layer as described above not only have excellent thermal insulation and compressibility properties, but they also exhibit suitable differential burst properties in the thickness direction and the xy-plane. This combination of properties allows these materials to be particularly suitable to be placed adjacent or immediately adjacent vent ports within a battery cell so that, if an adverse event occurs, the polymeric foam layer ruptures in the z-direction allowing gases and debris to escape, while maintaining the neighboring cells in thermal isolation. That is, the materials described here allow a gas-flow control in desired direction when needed.

[0031] The described thermally-insulating polymeric foam layers are further characterized by one or more of the following advantageous benefits: a) excellent cushioning performance when used in battery assemblies; b) excellent resistance to compression forces and high-pressure conditions throughout the lifetime of a battery assembly; c) ability to maintain a foam structure for the polymeric foam layer even under high-pressure conditions; d) easy and cost-effective manufacturing method, based on readily available starting materials and minimized manufacturing steps; e) construction simplicity and versatility; f) excellent formulation flexibility of the polymeric foam layer for use herein; g) low thermal conductivity; h) ability to be produced in relatively low thicknesses; i) ready- to-use article in particular for thermal management applications; j) prolonged durability of the energy storage assemblies using the cushioning article of the disclosure; and k) ability to be placed over various substrates such as metallic or polymeric surfaces without requiring adhesion-promoting processing steps or compositions.

[0032] Those are particularly unexpected findings for various reasons. For instance, thermal insulation and heat resistance stability are usually not expected to be obtained with compressible (soft) porous polymeric foam layers, in particular foam layers having a relatively low thickness, and more in particular with compression applied.

[0033] Thermally-insulating polymeric foam layers (also referred in this disclosure as “articles”) are suitable for use in various industrial applications, in particular for thermal management applications where a differential burst pressure is needed in different directions. The articles of the present disclosure are particularly suitable for thermal management applications in the transportation industry (in particular automotive industry), in particular as athermal barrier adjacent or immediately adjacent vent ports within battery cell. However, the use of the polymeric foam layers of this application are also suitable for use as spacers having thermal runaway barrier properties in between battery cells within rechargeable electrical energy storage systems, in particular battery modules. Advantageously still, the articles of the disclosure may be used in the manufacturing of battery modules, in particular electric -vehicle battery modules and assemblies. In a beneficial aspect, the articles as described herein are suitable for manual or automated handling and application, in particular by fast robotic equipment, due in particular to its excellent robustness, dimensional stability and handling properties. In some advantageous aspects, the articles described herein are also able to meet challenging fire regulation norms due their outstanding flame resistance and heat stability characteristics.

[0034] In the context of the present disclosure, the term “adjacent” is meant to designate two superimposed films or layers which are arranged either directly next to each other, i.e. which are abutting or in direct contact with each other, or which are arranged not directly next to each other, i.e. when at least one additional film or layer is arranged between the initial two superimposed films or layers, for example an adhesive layer or a primer layer. In the context of the present disclosure, the term “immediately adjacent” is meant to designate two superimposed films or layers which are arranged directly next to each other, i.e. which are abutting or in direct contact with each other.

[0035] The terms top and bottom layers or films, respectively, are used herein to denote the position of a layer or film relative to the surface of the substrate bearing such layer or film in the process of forming the polymeric foam layer.

[0036] In this disclosure, the z-direction is taken along the thickness direction. In contrast, the xy- plane represents a plane that is perpendicular to the z-direction. That is, with respect to the xy-plane, the z-direction would be a normal vector to the xy-plane. Accordingly, the xy-direction represent any direction within the xy-plane, and is also perpendicular to the z-direction.

[0037] Thermally-Insulating Polymeric Foam Lavers

[0038] The inventors have surprisingly found certain thermally-insulating polymeric foam layers that not only have excellent thermal insulation and compressibility properties, but they also exhibit suitable differential burst properties in the thickness direction and the xy-plane.

[0039] In other embodiments, the uncompressed polymeric foam layer has a burst pressure of equal or less than 10 psi in the thickness direction (z-direction) under the z-Burst Test, while at the same time having a burst pressure equal to, or higher than, 80 psi in the xy direction for a compression ratio of 30% under the xy-Burst Test.

[0040] In yet other embodiments, the uncompressed polymeric foam layer has a burst pressure of equal or less than 10 psi in the thickness direction (z-direction) under the z-Burst Test, while at the same time having a burst pressure equal to, or higher than, 90 psi in the xy direction for a compression ratio of 30% under the xy-Burst Test.

[0041] In some embodiments, the uncompressed polymeric foam layer has a burst pressure of equal or less than 10 psi in the thickness direction (z-direction) under the z-Burst Test, while at the same time having a burst pressure equal to, or higher than, 150 psi in the xy direction for a compression ratio of 50% under the xy-Burst Test. In other embodiments, the polymeric foam layer for use herein comprises a material having a weight loss after three minutes at 600°C of no greater than 70%, no greater than 60%, no greater than 50%, no greater than 40%, no greater than 30%, or even no greater than 25%, when measured according to the thermal stability test method described in the experimental section.

[0042] The types of polymeric foam layers as described above are typically referred to as thermally resistant materials or thermally resistant foam layers.

[0043] According to an exemplary aspect, the polymeric foam layer of the disclosure comprises a material selected from the group consisting of elastomeric materials, thermoplastic materials, thermoplastic elastomer materials, thermoplastic non-elastomeric materials, thermoset materials, and any combinations or mixtures thereof.

[0044] In one advantageous aspect, the polymeric foam layer for use herein comprises a material selected from the group consisting of silicone elastomers, fluorosilicone rubber, aromatic polyamides, polybenzimidazoles, polysulfides, polyimides, polysulfones, polyetherketones, polyurethanes, polyolefins (in particular polyethylene, polypropylene and ethyl vinyl acetate), and any combinations or mixtures thereof.

[0045] In a more advantageous aspect, the polymeric foam layer for use herein comprises a material selected from the group consisting of elastomeric materials.

[0046] In another more advantageous aspect, the polymeric foam layer for use herein comprises a material selected from the group consisting of silicone elastomers, in particular silicone rubbers, more in particular organopoly siloxane polymers.

[0047] In one particularly advantageous aspect of the disclosure, the polymeric foam layer for use herein is a silicone rubber foam layer. According to an advantageous aspect, the polymeric foam layer for use herein comprises a non-syntactic foam.

[0048] The polymeric foam layer for use herein may comprise additional (optional) ingredients or additives depending on the targeted application.

[0049] In a particular aspect of the disclosure, the polymeric foam layer for use herein further comprises an additive which is in particular selected from the group consisting of flame retardants, softeners, hardeners, filler materials, tackifiers, nucleating agents, colorants, pigments, conservatives, rheology modifiers (in particular 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, thermally insulating particles, electrically conducting particles, electrically insulating particles, infrared opacifier particles, and any combinations or mixtures thereof.

[0050] Fillers

[0051] In one beneficial aspect, the polymeric foam layer further comprises a non-flammable (or non-combusting) filler material. In a more beneficial aspect, the non-flammable filler material for use herein is selected from the group of inorganic fibers, in particular from the group chosen from inorganic particles, mineral fibers, mineral wool, silicate fibers, ceramic fibers, glass fibers, carbon fibers, graphite fibers, asbestos fibers, aramide fibers, and any combinations or mixtures.

[0052] In an advantageous aspect of this disclosure, the polymeric foam layer comprises inorganic particles. The inorganic particles can be solid, hollow or contain multiple voids. Such particles can include, e.g., particles of unexpanded intumescent material, irreversibly or permanently expanded intumescent material, diatomaceous earth, inorganic aerogel material, polymeric ceramic (e.g., silica) material, irreversibly or permanently expanded perlite mineral, hollow ceramic or otherwise inorganic (e.g., glass) microspheres, etc. Such inorganic particles that contain voids such as, e.g., those found in irreversibly or permanently expanded vermiculite are particularly desirable. Particles of irreversibly or permanently expanded perlite mineral also contain voids, but perlite mineral is harder and less compressible than vermiculite mineral. Silica-based and other aerogel particles also contain voids.

[0053] In one preferred embodiment, the thermally-insulating polymeric foam layer comprises one or more fillers are chosen from calcium carbonate and aluminum trihydrate.

[0054] In some embodiments, the thermally-insulating polymeric foam layer comprises a total amount of inorganic particle fillers of at least 35 wt% by weight with respect to the total weight of the polymeric foam layer. In other embodiments, the total amount of inorganic fillers is at least 40 wt%, or at least 45 wt%, or at least 50 wt%, or at least 55 wt% with respect to the total weight of the polymeric foam layer. In yet other embodiments, the total amount of inorganic fillers ranges from 30 wt% to 80, or 35 wt% to70, or from 40 wt% to 60 with respect to the total weight of the polymeric foam layer.

[0055] In other embodiments, the thermally-insulating polymeric foam layer further comprising fibers chosen from mineral fibers, silicate fibers, ceramic fibers, asbestos fibers, aramide fibers, and any combinations or mixtures. In a preferred embodiment, the fibers are mineral fibers. In yet other embodiments, the fibers are mineral fibers 500 microns in length.

[0056] In the context of the present disclosure, it has indeed surprisingly been discovered that a polymeric foam (in particular silicone rubber foam) which further comprises mineral fibers are provided with excellent thermal resistance and thermal stability characteristics, as well as improved resistance to surface cracking and surface brittleness even after prolonged exposure to temperatures up to 600°C. Without wishing to be bound by theory, it is believed that these beneficial characteristics are due in particular to the excellent compatibility of the mineral fibers (in particular silicate fibers) with the surrounding polymeric matrix (in particular silicone polymer matrix), which participates in densifying and mechanically stabilizing the resulting matrix.

[0057] In a particular aspect of this execution, the non-flammable filler material in the form of fibers for use herein is comprised in the polymeric foam in an amount ranging from 0.5 to 40 wt.%, from 1 to 30 wt.%, from 1 to 20 wt.%, from 1 to 10 wt.%, from 1 to 8 wt.%, from 2 to 8 wt.%, from 2 to 6 wt.%, or even from 3 to 6 wt.%, based on the overall weight of the precursor composition of the polymeric foam. In other embodiments, the fibers are present in an amount from 1 wt% to 10 wt%, or from 2 wt% to 5 wt%, or from 2.5 wt% to 4 wt% with respect to the total weight of the polymeric foam layer.

[0058] In another typical aspect, the polymeric foam layer for use herein is free of thermally conductive fillers.

[0059] According to yet another advantageous aspect of the disclosure, the polymeric foam layer for use herein has a thermal conductivity no greater than 0.15 W / m / K, no greater than 0.1 W / m / K, no greater than 0.05 W / m / K, or even no greater than 0.08 W / m / K, when measured according to the test method described in the experimental section.

[0060] According to one advantageous aspect of the disclosure, the uncompressed polymeric foam layer for use herein has a density 0.3 g / cm3to 0.5 g / cm3when measured according to the method described in the experimental section.

[0061] According to still another advantageous aspect of the disclosure, the polymeric foam layer for use herein has a hardness (Shore 00) greater than 10, greater than 15, greater than 20, greater than 25, greater than 30, greater than 40, or even greater than 50.

[0062] According to still another advantageous aspect of the disclosure, the polymeric foam layer for use herein has a hardness (Shore 00) in a range from 10 to 80, from 10 to 70, from 20 to 70, from 25 to 60, from 25 to 55, from 30 to 55, from 30 to 50, from 30 to 45, or even from 30 to 40.

[0063] According to still another advantageous aspect of the disclosure, the polymeric foam layer for use herein has heat transfer time to 150°C 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 according to the thermal insulation test method 1 described in the experimental section.

[0064] According to still another advantageous aspect of the disclosure, the polymeric foam layer for use herein has a heat transfer time to 150°C in a range from 20 to 200 seconds, from 40 to 200 seconds, from 60 to 200 seconds, from 100 to 200 seconds, from 120 to 200 seconds, from 140 to 200 seconds, from 160 to 200 seconds, or even from 160 to 180 seconds, when measured according to the thermal insulation test method 1 described in the experimental section.

[0065] According to yet another advantageous aspect of the disclosure, the polymeric foam layer for use herein has a thermal conductivity in a range from 0.1 to 1 W / m / K, from 0.2 to 1 W / m / K, or even from 0.2 to 0.8 W / m / K, when measured according to the test method described in the experimental section.

[0066] According to yet another advantageous aspect of the disclosure, the polymeric foam layer for use herein undergoes a ceramization process at a temperature no greater than 600°C, no greater than 550°C, no greater than 500°C, no greater than 450°C, no greater than 400°C, no greater than 350°C, no greater than 300°C, or even no greater than 250°C. According to yet another advantageous aspect of the disclosure, the polymeric foam layer for use herein undergoes a ceramization process at a temperature in a range from 200°C to 600°C, from 200°C to 550°C, from 200°C to 500°C, from 200°C to 450°C, from 200°C to 400°C, from 200°C to 350°C, from 250°C to 350°C, or even from 250°C to 300°C.

[0067] In the context of the present disclosure, it has indeed surprisingly been discovered that a polymeric foam layer which has the ability to undergo a ceramization process, in particular at a relatively low temperature, is provided with excellent thermal resistance and thermal stability characteristics.

[0068] According to still another advantageous aspect of the disclosure, the polymeric foam layer for use herein has a V-0 classification, when measured according to the UL-94 standard flammability test method.

[0069] In one advantageous aspect, the polymeric foam layer for use herein has a thickness no greater than 10000 micrometers, no greater than 8000 micrometers, no greater than 6000 micrometers, no greater than 5000 micrometers, no greater than 4000 micrometers, no greater than 3000 micrometers, no greater than 2500 micrometers.

[0070] In another advantageous aspect, the polymeric foam layer for use herein has a thickness in a range from 100 to 10000 micrometers, from 100 to 8000 micrometers, from 100 to 6000 micrometers, from 200 to 5000 micrometers, from 300 to 5000 micrometers, from 300 to 4500 micrometers, from 300 to 4000 micrometers, from 500 to 4000 micrometers.

[0071] According to one particular aspect of the disclosure, the polymeric foam layer for use herein may be provided with the first solid film and / or the second solid film. In an alternative execution, the polymeric foam layer may not be provided with any of the first solid film and / or the second solid film.

[0072] As will be apparent to those skilled in the art, the polymeric foam layer for use herein may take various forms, shapes and sizes depending on the targeted application. Similarly, the polymeric foam layer for use herein may be post-processed or converted as it is customary practice in the technical field.

[0073] According to one exemplary aspect, the polymeric foam layer for use herein may take the form of a roll which is wound, in particular level-wound, around a core. The polymeric foam layer in the wound roll may or may not be provided with the first solid film and / or the second solid film.

[0074] According to one exemplary aspect, the polymeric foam layer for use herein may be cut into smaller pieces of various forms, shapes and sizes.

[0075] Method of preparing typical silicone polymeric foam layers

[0076] According to an advantageous aspect, the silicone rubber foam layer for use herein is obtainable from a curable and foamable precursor of the silicone rubber foam layer, in particular an in-situ foamable precursor composition.

[0077] Precursor compositions of the silicone rubber foam for use herein are not particularly limited, as long as they are curable and foamable. Any curable and foamable precursors of a silicone rubber foam commonly known in the art may be formally used in the context of the present disclosure. Suitable curable and foamable precursors of a silicone rubber foam for use herein may be easily identified by those skilled in the art in the light of the present disclosure.

[0078] According to a more advantageous aspect, the precursor of the silicone rubber foam layer for use herein is a two-part composition.

[0079] In a typical aspect, the two-part precursor composition of the silicone rubber foam is selected from the group consisting of addition curing type two-part silicone compositions, condensation curing type two-part silicone compositions, and any combinations or mixtures thereof.

[0080] In a preferred aspect, the precursor of the silicone rubber foam for use herein comprises an addition curing type two-part silicone composition, in particular an addition curing type two-part organopolysiloxane composition.

[0081] Suitable addition curing type two-part organopolysiloxane compositions for use herein as the precursor of the silicone rubber foam may be easily identified by those skilled in the art based on the disclosure below..

[0082] According to a particularly advantageous aspect of the present disclosure, the precursor of the silicone rubber foam for use herein comprises: at least one organopolysiloxane compound A; at least one organohydrogenpolysiloxane compound B comprising at least two, in particular at least three hydrogen atoms per molecule; at least one hydroxyl containing compound C; an effective amount of a curing catalyst D, in particular a platinum-based curing catalyst; and optionally, a foaming agent.

[0083] In an exemplary aspect, the at least one organopolysiloxane compound A for use herein has the following formula: wherein:

[0084] R and R”, are independently selected from the group consisting of Ci to C30 hydrocarbon groups, and in particular R is an alkyl group chosen from the group consisting of methyl, ethyl, propyl, trifluoropropyl, and phenyl, and optionally R is a methyl group;

[0085] R’ is a Ci to C20 alkenyl group, and in particular R’ is chosen from the group consisting of vinyl, allyl, hexenyl, decenyl and tetradecenyl, and more in particular R’ is a vinyl group;

[0086] R” is in particular an alkyl group such as a methyl, ethyl, propyl, trifluoropropyl, phenyl, and in particular R” is a methyl group; and n is an integer having a value in a range from 5 to 1000, and in particular from 5 to 100.

[0087] In another exemplary aspect, the at least one hydroxyl containing compound C for use herein is selected from the group consisting of alcohols, polyols in particular polyols having 3 to 12 carbon atoms and having an average of at least two hydroxyl groups per molecule, silanols, silanol containing organopolysiloxanes, silanol containing silanes, water, and any combinations or mixtures thereof.

[0088] In still another exemplary aspect, the at least one hydroxyl containing compound C for use herein is selected from the group consisting of silanol containing organopolysiloxanes.

[0089] According to an advantageous aspect of the present disclosure, the polymeric foam layer for use herein is obtainable by a process comprising the steps of: providing a substrate; providing a first solid film and applying it onto the substrate; providing a coating tool provided with an upstream side and a downstream side, wherein the coating tool is offset from the substrate to form a gap normal to the surface of the substrate; moving the first solid film relative to the coating tool in a downstream direction; providing a curable (and foamable) precursor of the polymeric foam to the upstream side of the coating tool thereby coating the precursor of the polymeric foam through the gap as a layer onto the substrate provided with the first solid film; providing a second solid film and applying it (at least partly) 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 the (adjacent) layer of the precursor of the silicone rubber foam; foaming or allowing the precursor of the porous polymeric foam to foam; curing or allowing the layer of the precursor of the polymeric foam to cure thereby forming the polymeric foam layer; optionally, exposing the layer of the precursor of the polymeric foam to a thermal treatment; and optionally, removing the first solid film and / or the second solid film from the polymeric foam layer.

[0090] According to an aspect of this disclosure, the precursor of the polymeric foam for use herein is an in-situ foamable composition, meaning that the foaming of the precursor occurs without requiring any additional compound, in particular external compound.

[0091] According to another advantageous aspect, the foaming of the precursor of the polymeric foam for use herein is performed with a gaseous compound, in particular hydrogen gas.

[0092] In a more advantageous aspect, the foaming of the precursor of the polymeric foam for use herein is performed by any of gas generation or gas injection.

[0093] According to a preferred aspect, the foaming of the precursor of the polymeric foam for use herein is performed by gas generation, in particular in-situ gas generation.

[0094] In an alternative aspect, the precursor of the polymeric foam for use herein further comprises an optional blowing agent.

[0095] Substrates for use herein are not particularly limited. Suitable substrates for use herein may be easily identified by those skilled in the art in the light of the present disclosure.

[0096] In a typical aspect of the disclosure, the substrate for use herein is a temporary support used for manufacturing purpose and from which the silicone rubber foam layer is separated and removed subsequent to foaming and curing. The substrate may optionally be provided with a surface treatment adapted to allow for a clean removal of the silicone rubber foam layer from the substrate (through the first solid film). Advantageously, the substrate for use herein and providing a temporary support may be provided in the form of an endless belt. Alternatively, the substrate for use herein may be a stationary (static) temporary support.

[0097] In one particular aspect of the disclosure, the polymeric foam layer obtained after foaming and curing is separated from the substrate and can be wound up, for example, into a roll.

[0098] According to one advantageous aspect of the disclosure, the substrate for use herein comprises a material selected from the group consisting of polymers, metals, ceramics, composites, and any combinations or mixtures thereof.

[0099] In a preferred embodiment, the substrate for the thermally-insulating polymeric foam layer is a thermally-resistant layer as described below.

[0100] The polymeric foam layer for use in the disclosure may be obtainable by a process using a coating tool provided with an upstream side and a downstream side. The coating tool is offset from the substrate to form a gap normal to the surface of the substrate.

[0101] Coating tools for use herein are not particularly limited. Any coating tool commonly known in the art may be used in the context of the present disclosure. Suitable coating tools for use herein may be easily identified by those skilled in the art in the light of the present disclosure.

[0102] The coating tools useful in the present disclosure each have an upstream side (or surface) and a downstream side (or surface). In a typical aspect, the coating tool for use herein is further provided with a bottom portion facing the surface of the substrate receiving the precursor of the polymeric foam. The gap is measured as the minimum distance between the bottom portion of the coating tool and the exposed surface of the substrate. The gap can be essentially uniform in the transverse direction (i.e. in the direction normal to the downstream direction) or it may vary continuously or discontinuously in the transverse direction, respectively. The gap between the coating tool and the surface of the substrate is typically adjusted to regulate the thickness of the respective coating in conjunction with other parameters including, for example, the speed of the substrate in the downstream direction, the type of the coating tool, the angle with which the coating tool is oriented relative to the normal of the substrate, and the kind of the substrate.

[0103] In one advantageous aspect of the disclosure, the gap formed by the coating tool from the substrate (coating tool gap) is in a range from 10 to 3000 micrometers, from 50 to 2500 micrometers, from 50 to 2000 micrometers, from 50 to 1500 micrometers, from 100 to 1500 micrometers, from 100 to 1000 micrometers, from 200 to 1000 micrometers, from 200 to 800 micrometers, or even from 200 to 600 micrometers.

[0104] The coating tool for use herein can be arranged normal to the surface of the substrate, or it can be tilted whereby the angle between the substrate surface and the downstream side (or surface) of the coating tool is in arrange from 50° to 130°, or even from 80° to 100°. The coating tool useful in the present disclosure is typically solid and can be rigid or flexible. The coating tool for use herein may take various shapes, forms and sizes depending on the targeted application and expected characteristics of the silicone rubber foam layer.

[0105] According to a typical aspect of the disclosure, the coating tool for use herein is selected from the group consisting of coating knifes, coating blades, coating rolls, coating roll blades, and any combinations thereof.

[0106] In an advantageous aspect, the coating tool for use herein is selected from the group of coating knifes. It has been indeed found that the use of a coating tool in the form of a coating knife provides a more reproducible coating process and better-quality coating, which translates into a silicone rubber foam layer provided with advantageous properties.

[0107] In another advantageous aspect, the coating tool for use herein is selected from the group of coating rolls and air knives.

[0108] According to another advantageous aspect, the cross-sectional profde of the bottom portion of the coating tool (in particular, a coating knife) in the longitudinal direction is designed so that the precursor layer is formed, and the excess precursor is removed. Typically, the cross-sectional profde of the bottom portion which the coating tool exhibits at its transversely extending edge facing the substrate, is essentially planar, curved, concave or convex.

[0109] According to an advantageous aspect of the present disclosure, the polymeric foam layer of the disclosure is obtainable by a process wherein the step of providing a curable (and foamable) precursor of the polymeric foam to the upstream side of the coating tool is performed immediately prior to the step of providing a second solid fdm and applying it 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 the (adjacent) layer of the precursor of the polymeric foam.

[0110] According to another advantageous aspect of the present disclosure, the step of foaming or allowing the precursor of the polymeric foam to foam and the step of curing or allowing the layer of the precursor of the polymeric foam to cure thereby forming the polymeric foam layer are performed simultaneously.

[0111] The solid films for use herein as the first and the second solid films are not particularly limited. Any solid films commonly known in the art may be formally used in the context of the present disclosure. Suitable solid films for use herein may be easily identified by those skilled in the art in the light of the present disclosure.

[0112] According to one advantageous aspect, 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 meant to refer to impermeability to liquids and gaseous compounds, in particular to gaseous compounds.

[0113] According to another advantageous aspect of the disclosure, the first solid film and / or the second solid film for use herein are selected from the group consisting of polymeric films, metal films, composite films, and any combinations thereof.

[0114] In a more advantageous aspect of the disclosure, the first solid film and / or the second solid film for use herein are selected from the group consisting of polymeric films, in particular comprising a polymeric material selected from the group consisting of thermoplastic polymers.

[0115] In still a more advantageous aspect of the disclosure, the first solid film and / or the second solid film for use herein are polymeric films, wherein the polymeric material is selected from the group consisting of polyesters, polyethers, polyolefins, polyamides, polybenzimidazoles, polycarbonates, polyether sulfones, polyoxymethylenes, polyetherimides, polystyrenes, polyvinyl chloride, and any mixtures or combinations thereof.

[0116] In still a more advantageous aspect of the disclosure, the first solid film and / or the second solid film for use herein are polymeric films comprising a polymeric material selected from the group consisting of polyesters, polyolefins (in particular PP and PE), polyetherimides, and any mixtures or combinations thereof.

[0117] In a particularly advantageous aspect, the first solid film and / or the second solid film for use in the present disclosure are polymeric films comprising a polymeric material selected from the group consisting of polyesters, in particular polyethylene terephthalate.

[0118] According to an advantageous aspect of the present disclosure, the polymeric foam layer of the disclosure is obtainable by a process wherein the first solid film is applied to the bottom surface of the layer of the precursor of the polymeric foam, and the second solid film is applied to the top (exposed) surface of the layer of the precursor of the polymeric foam.

[0119] In a typical aspect of the disclosure, the first solid film and / or the second solid film are contacted directly to the adjacent polymeric foam layer.

[0120] In another advantageous aspect of the present disclosure, the first major (top) surface and the second (opposite) major (bottom) surface of the polymeric foam layer and / or the first solid film and / or the second solid film are free of any adhesion-promoting compositions or treatments, in particular free of priming compositions, adhesive compositions and physical surface treatments.

[0121] In an alternatively advantageous aspect of the present disclosure, the first major (top) surface and the second (opposite) major (bottom) surface of the polymeric foam layer and / or the first solid film and / or the second solid film comprises an adhesion-promoting compositions or treatments, in particular priming compositions, adhesive compositions and physical surface treatments.

[0122] In still another advantageous aspect of the disclosure, no intermediate layers of any sorts are comprised in-between the first major (top) surface or the second (opposite) major (bottom) surface of the polymeric foam layer and the first solid film and / or the second solid film. In a typical aspect of the disclosure, the first and second solid films are smoothly contacted to the corresponding surfaces of the silicone rubber foam layer in a snug fit thereby avoiding (or at least reducing) the inclusion of air between the solid films and the corresponding surfaces of the polymeric foam layer.

[0123] According to one advantageous aspect, the polymeric foam layer for use herein comprises gaseous cavities, in particular gaseous hydrogen cavities, air gaseous cavities, and any mixtures thereof.

[0124] According to one advantageous aspect, the polymeric foam layer for use herein comprises gaseous cavities having an oblong shape in the direction of the layer thickness (i.e. in the direction perpendicular to the plane formed by the foam layer).

[0125] According to a more advantageous aspect, the gaseous cavities that may be present in the silicone rubber foam layer have an elongated oval shape in the direction of the layer thickness.

[0126] Advantageously still, the gaseous cavities for use herein are not surrounded by any ceramic or polymeric shell (other than the surrounding silicone polymer matrix).

[0127] In one particular aspect, the gaseous cavities for use herein have a mean average size (of its greatest dimension) no greater than 500 micrometers, no greater than 400 micrometers, no greater than 300 micrometers, no greater than 200 micrometers, no greater than 150 micrometers, no greater than 120 micrometers, no greater than 100 micrometers, no greater than 80 micrometers, no greater than 60 micrometers, no greater than 50 micrometers, no greater than 40 micrometers, no greater than 30 micrometers, or even greater than 20 micrometers (when calculated from SEM micrographs).

[0128] In another particular aspect, the gaseous cavities for use herein have a mean average size (of the greatest dimension) in a range from 5 to 3000 micrometers, from 5 to 2000 micrometers, from 10 to 1500 micrometers, from 20 to 1500 micrometers, from 20 to 1000 micrometers, from 20 to 800 micrometers, from 20 to 600 micrometers, from 20 to 500 micrometers, or even from 20 to 400 micrometers (when calculated from SEM micrographs).

[0129] According to atypical aspect, the polymeric foam layer for use herein is free of hollow cavities (surrounded by any ceramic or polymeric shell) selected from the group consisting of hollow microspheres, glass bubbles, expandable microspheres, in particular hydrocarbon filled expandable microspheres, hollow inorganic particles, expanded inorganic particles, and any combinations or mixtures thereof.

[0130] EXEMPLARY EMBODIMENTS

[0131] The following list exemplifies certain embodiments of the present disclosure.

[0132] 1. A thermally-insulating polymeric foam layer, comprising

[0133] • a silicone elastomer,

[0134] • one or more fillers

[0135] • wherein the silicone elastomer is a cured foamed polymer • wherein the polymeric foam layer has a width, a length, and a thickness,

[0136] • wherein the uncompressed polymeric foam layer has a burst pressure of equal to, or less than 10 psi in the thickness direction (z -direction) under the z-Burst Test,

[0137] • wherein the polymeric foam layer has a burst pressure equal to, or higher than, 80psi in the xy direction for a compression ratio of 30% under the xy-Burst Test,

[0138] • wherein the one or more fdlers are inorganic;

[0139] • wherein the total amount of inorganic fillers is at least 40 wt% by weight with respect to the total weight of the polymeric foam layer. A thermally-insulating polymeric foam layer, comprising

[0140] • a silicone elastomer,

[0141] • one or more fillers

[0142] • wherein the silicone elastomer is a cured foamed polymer

[0143] • wherein the polymeric foam layer has a width, a length and a thickness,

[0144] • wherein the uncompressed polymeric foam layer has a burst pressure of less than 10 psi in the thickness direction (z-direction) under the z-Burst Test,

[0145] • wherein the polymeric foam layer has a burst pressure higher than 80psi in the xy direction for a compression ratio of 30% under the xy-Burst Test,

[0146] • wherein one or more fillers are inorganic;

[0147] • wherein the total amount of inorganic fillers is at least 30 wt% by weight with respect to the total weight of the polymeric foam layer. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the silicone elastomer is an organopolysiloxane compound. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the thermally-insulating polymeric foam layer is obtainable from a precursor that comprises a) at least one organopolysiloxane compound A; b) at least one organohydrogenpolysiloxane compound B comprising at least two, in particular at least three hydrogen atoms per molecule; c) at least one hydroxyl containing compound C; d) an effective amount of a curing catalyst D, in particular a platinum-based curing catalyst; and e) optionally, a foaming agent. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the at least one organopolysiloxane compound A has the following formula: wherein:

[0148] R and R”, are independently selected from the group consisting of Cl to C30 hydrocarbon groups, and in particular R is an alkyl group chosen from the group consisting of methyl, ethyl, propyl, trifluoropropyl, and phenyl, and optionally R is a methyl group;

[0149] R’ is a C 1 to C20 alkenyl group, and in particular R’ is chosen from the group consisting of vinyl, allyl, hexenyl, decenyl and tetradecenyl, and more in particular R’ is a vinyl group;

[0150] R” is in particular an alkyl group such as a methyl, ethyl, propyl, trifluoropropyl, phenyl, and in particular R” is a methyl group; and n is an integer having a value in a range from 5 to 1000, and in particular from 5 to 100. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the uncompressed polymeric foam layer has a burst pressure of equal or less than 10 psi in the thickness direction (z-direction) under the z-Burst Test and the polymeric foam layer has a burst pressure higher than 90psi in the xy direction for a compression ratio of 30% under the xy-Burst Test. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the uncompressed polymeric foam layer has a burst pressure of equal or less than 10 psi in the thickness direction (z-direction) under the z-Burst Test and the polymeric foam layer has a burst pressure higher than 15 Opsi in the xy direction for a compression ratio of 50% under the xy-Burst Test. A thermally-insulating polymeric foam layer according to any of the preceding claims, further comprising fibers chosen from mineral fibers, silicate fibers, ceramic fibers, asbestos fibers, aramide fibers, and any combinations thereof. A thermally-insulating polymeric foam layer according to any of the preceding claims, further comprising fibers chosen from mineral fibers 500 microns in length. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the fibers are present in an amount 1 wt% to 10 wt% with respect to the total weight of the polymeric foam layer. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the fibers are present in an amount 2 wt% to 5 wt% with respect to the total weight of the polymeric foam layer. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the fibers are present in an amount 2.5 wt% to 4 wt% with respect to the total weight of the polymeric foam layer.

[0151] 13. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the one or more fillers are chosen from calcium carbonate, aluminum trihydrate.

[0152] 14. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the total amount of inorganic fillers is at least 40 wt% by weight with respect to the total weight of the polymeric foam layer.

[0153] 15. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the total amount of inorganic fillers is at least 50 wt% by weight with respect to the total weight of the polymeric foam layer.

[0154] 16. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the total amount of inorganic fillers is at least 55 wt% by weight with respect to the total weight of the polymeric foam layer.

[0155] 17. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the total amount of inorganic fillers is from 30 wt% to 80wt% wt% by weight with respect to the total weight of the polymeric foam layer.

[0156] 18. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the total amount of inorganic fillers is from 35 wt% to 70wt% wt% by weight with respect to the total weight of the polymeric foam layer.

[0157] 19. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the polymeric foam layer exhibits a pressure of at least 100 kPa when subjected to a compression of 30%. 0. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the polymeric foam layer exhibits a pressure of at least 200 kPa when subjected to a compression of 30%. 1. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the polymeric foam layer exhibits a pressure of at least 250 kPa when subjected to a compression of 30%. 2. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the time to the first flame breakthrough under the Torch Test is at least 10 seconds. 3. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the time to the first flame breakthrough under the Torch Test is at least 12 seconds. 4. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the uncompressed density of the polymeric foam layer ranges from 0.3 g / cm3to 0.5 g / cm3. 5. A battery module comprising a thermally-insulating polymeric foam layer according to any of the preceding claims. 26. A batery module comprising two or more batery cells,

[0158] • wherein each batery cell comprises a gas-flow control system,

[0159] • wherein each gas-flow control system comprises a thermally-insulating polymeric foam layer according to any of the preceding claims, and

[0160] • wherein the thermally-insulating polymeric foam layer is capable of allowing degassing of the batery cell in the z-direction (thickness) but prevents degassing in the x-y directions.

[0161] 27. A batery module comprising the thermally-insulating polymeric foam layer according to any of the preceding claims.

[0162] A batery module according to claim 23, comprising one or more batery cells, wherein the thermally-insulating polymeric foam layer is in contact with at least one venting port of the at least one batery cell.

[0163] EXAMPLES

[0164] The present disclosure is further illustrated by the following examples. These examples are merely for illustrative purposes only and are not meant to be limiting on the scope of the appended claims. Where applicable, brand names and trademarked names are shown in all capital leters and / or numbers.

[0165] Table 1. Materials

[0166] Test Methods

[0167] Compression Test

[0168] The compression test is performed using a tensile tester from Zwick in compression mode. The sample has a size of 50 x 50 mm and a thickness > 1000 micrometers. The test was performed at 23°C. The upper plate of the compression tester was moved with a speed of 1 mm / min until a maximum force of at least 1.2 MPa is reached. Then, the upper plate was moved up back to the starting position with the same speed of 1 mm / min for a full load / unload cycle. The compression force (in kPa) required to reach various compression values were recorded.

[0169] Coating Weight

[0170] The coating weight of the polymeric foam layers is measured by weighing a sample of 100 cm2cut out of the sample layer using a circle cutter. The coating weight is then converted in g / m2.

[0171] Thickness

[0172] The thickness of the polymeric foam layers is measured using a thickness gauge with a minimum foot area of 650 mm2. The pressure of the gauge foot was held to a maximum of 725 Pa.

[0173] Density

[0174] The density (in kg / m3) of the silicone rubber foam layers is calculated by dividing the coating weight of the foam layers (in kg / m2) by their thickness (in m). z-Burst Test (thickness direction)

[0175] The z-direction burst test is performed by first cutting a rectangle 5cm x 14.5cm out of the foam. The rectangle of foam is then centered is sandwiched between two stainless steel plates, each with an oval opening with 1800 mm2(FIGs. 3A and 3A). One of the plates is connected to the pressure inlet. Shims were placed around each bolt hole to set the compression to 50%-of the total foam thickness (FIG. 3A). The compression outlet fixture is then aligned with the inlet fixture and the 6 screws are tightened until the outlet fixture surface makes contact with the shims (FIG. 3B). The pressure inlet fixture is then connected to a compressed air regulator (FIG. 3C). Starting pressure is 5 psi and pressure is increased in 2 psi intervals with a 15 second dwell between increases. Pressures at which noticeable leakage first occur and / or that the foam sample bursts through the open uncompressed center region in the Z direction are recorded.

[0176] Xy-Burst Test (xy-direction or plane direction)

[0177] The plane direction burst test is performed by first cutting a ring foam sample with 2-inch outer and 1.25 -inch inner diameter out of the foam. The ring of foam is then centered around the pressure inlet fixture (see FIG. 4A). Shims were placed around each bolt hole to set the compression to 20%, 30% or 50%-of the total foam thickness. A steel plate is put on top of foam ring to prevent burst in z- direction. The compression outlet fixture is then aligned with the inlet fixture and the screws are tightened until the outlet fixture surface makes contact with the shims (see FIG. 4D). Starting pressure is 10 psi and pressure is increased in 2 psi intervals with a 15 second dwell between increases. Pressures at which the sample material bursts through the open uncompressed center region in the xy-direction are recorded.

[0178] Torch Test

[0179] A torch test fixture is used to apply compression to the foam sheet samples on the outer periphery of 90 mm x 50 mm foam samples, with an uncompressed thickness as described in Table 3. The fixture leaves an uncompressed center of the dimensions shown in FIG. 5. The sheet samples are compressed to a known thickness by using steel spacers of known thickness placed in the 1mm deep depressions on each end as shown in FIG. 5 and FIG. 6. The opening of torch test fixture is 2.76 inch in length and 0.98 inch in height.

[0180] A “Champion” hydrogen oxygen burner obtained from Bethlehem Apparatus Company, Inc. Hellertown, PA was used to generate a flame measuring 1200 °C at 1 inch from the face of the burner. Once a steady state temperature is reached the foam sheet assembly is then slid in front of the burner at a distance of 2.375 inches (FIG. 7) and exposed to the burner until the flame bums through the foam sample. The time in seconds of first flame breakthrough on the backside of the test sample is recorded. Porous Foam Constructions

[0181] Table 2: Formulation

[0182] Porous Foam Preparatory Examples:

[0183] The exemplary made silicone rubber foam is prepared according to the following procedure: EB3242 Part B was mixed with specific amounts of IS74S or O520AV as described in Table 2 using a speedmixer at a speed of 1500 rpm for 120 seconds. All other identified filler materials (refer to Table 2) were added to EB3242 Part A and mixed using a speedmixer at a speed of 1500 rpm.

[0184] The quantities of materials in weight parts as identified in Table 2 were added to a 200 mb two-part cartridge system from Adchem GmbH. The two-part silicone system was mixed with a static mixer (MFH 10-18T) using a dispensing gun at 4 bar air pressure. After releasing 10 g of the mixed silicone in ajar, the mixture was additionally homogenized by hand using a wooden spatula for 10 seconds. This mixture was then coated with a knife coater with a defined gap thickness between two layers of solid film PETP. The obtained sheet began to expand, and the reaction was completed by putting the sheet in a forced air oven at elevated temperatures for at least 5 minutes.

[0185] Exemplary silicone rubber foam layers (Examples 1 to 3) and comparative example CE-1 to CE-2:

[0186] Table 3. The exemplary silicone rubber foam formulations Density

[0187] Table 4: Results of density calculations.

[0188] As can be seen from the results shown in Table 4, the silicone rubber foam layers according to the present disclosure (Examples 1 to 3) are provided with high density values, whereas the silicone rubber layer of comparative example CE-1 and CE-2 are provided with a relatively lower density value.

[0189] Compressibility performance

[0190] Table 5: Results of the compressibility performance test.

[0191] As can be seen from the results shown in Table 5, the silicone rubber foam layers according to the present disclosure are provided with excellent compressibility performance.

[0192] Table 6: In-plane (xy)- and thickness (z direction) burst test results

[0193] *4D = Not determined

[0194] As can be seen from the results shown in Table 6, the silicone rubber foam layers according to the present disclosure are provided with low burst pressure in thickness direction, but high burst pressure in plane direction.

Claims

CLAIMSWe claim:

1. A thermally-insulating polymeric foam layer, comprising• a silicone elastomer,• one or more fillers• wherein the silicone elastomer is a cured foamed polymer• wherein the polymeric foam layer has a width, a length, and a thickness,• wherein the uncompressed polymeric foam layer has a burst pressure of equal to, or less than 10 psi in the thickness direction (z-direction) under the z-Burst Test,• wherein the polymeric foam layer has a burst pressure equal to, or higher than, 80psi in the xy direction for a compression ratio of 30% under the xy-Burst Test,• wherein the one or more fillers are inorganic;• wherein the total amount of inorganic fillers is at least 40 wt% by weight with respect to the total weight of the polymeric foam layer.

2. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the silicone elastomer is an organopolysiloxane compound.

3. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the uncompressed polymeric foam layer has a burst pressure of equal or less than 10 psi in the thickness direction (z-direction) under the z-Burst Test and the polymeric foam layer has a burst pressure higher than 90psi in the xy direction for a compression ratio of 30% under the xy-Burst Test.

4. A thermally-insulating polymeric foam layer according to any of the preceding claims, further comprising fibers chosen from mineral fibers, silicate fibers, ceramic fibers, asbestos fibers, aramide fibers, and any combinations thereof.

5. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the fibers are present in an amount 1 wt% to 10 wt% with respect to the total weight of the polymeric foam layer.

6. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the one or more fillers are chosen from calcium carbonate, aluminum trihydrate.

7. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the total amount of inorganic fillers is from 35 wt% to 70wt% wt% by weight with respect to the total weight of the polymeric foam layer.

8. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the polymeric foam layer exhibits a pressure of at least 100 kPa when subjected to a compression of 30%.

9. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the polymeric foam layer exhibits a pressure of at least 200 kPa when subjected to a compression of 30%.

10. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the polymeric foam layer exhibits a pressure of at least 250 kPa when subjected to a compression of 30%.

11. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the time to the first flame breakthrough under the Torch Test is at least 10 seconds.

12. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the time to the first flame breakthrough under the Torch Test is at least 12 seconds.

13. A thermally-insulating polymeric foam layer according to any of the preceding claims, wherein the uncompressed density of the polymeric foam layer ranges from 0.3 g / cm3to 0.5 g / cm3.

14. A battery module comprising a thermally-insulating polymeric foam layer according to any of the preceding claims.

15. A battery module comprising two or more battery cells,• wherein each battery cell comprises a gas-flow control system,• wherein each gas-flow control system comprises a thermally-insulating polymeric foam layer according to any of the preceding claims, and• wherein the thermally-insulating polymeric foam layer is capable of allowing degassing of the battery cell in the z-direction (thickness) but prevents degassing in the x-y directions.

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