Silicone foam material for battery fire protection

Abstract

The present disclosure provides a method for producing silicone-based polymer foams containing pores. 50 A silicone-based fire-resistant material having a foam structure in which hollow fillers of 10 to 200 microns are bonded, wherein the density of the silicone-based fire-resistant material is 0.1 g / cc to 0.8 g / cc, the Shore A hardness is 1 to 40, and the cell size d of the silicone-based polymer foam is 50 The present invention relates to a silicone-based fireproof material having a particle size of 10 to 1000 microns.

Description

[Technical Field]

[0001] The present disclosure relates to a silicone-based fire-retardant material, a process for producing the same, and a battery packaging structure having the material, to the use of the silicone-based fire-retardant material in a battery packaging structure, and to a method for producing a battery packaging structure using the silicone-based fire-retardant material. [Background technology]

[0002] Driven by the development of Li-ion battery technology, the automotive industry has been dramatically transformed by electric vehicles (EVs) over the past decade. However, thermal runaway in EV batteries can pose serious fire risks and hazards, making it a major safety concern. The thermal runaway temperature of EV high-energy-density batteries can reach over 600°C. Few polymer composite materials can withstand such high temperatures. Today, thermal insulation materials are utilized to minimize the propagation of thermal runaway in EV batteries. Excellent thermal insulation properties, high flame retardancy, light weight, and good electrical insulation performance are required.

[0003] There are two known silicone solutions used to mitigate thermal runaway in batteries: one is silicone foam, which is usually chemically foamed but can also be physically foamed, and the other is silicone rubber syntactic foam, which incorporates hollow glass beads. Both are somewhat effective, but have limitations.

[0004] Chemically or physically foamed silicone foam pads are too soft for thermal runaway protection of prismatic and pouch cell battery modules. Battery expansion during the thermal runaway process can cause excessive compression of the silicone foam, resulting in poor thermal insulation performance. On the other hand, silicone rubber syntactic foam is essentially incompressible. While this is acceptable for many cylindrical cell arrays, it is detrimental for prismatic and pouch cells, as the latter experience significant expansion and contraction during charge and discharge cycles. Furthermore, the rubber density can still be too high, often resulting in lower flame resistance than required.

[0005] US Patent No. 10,501,597 (B2) discloses a silicone rubber syntactic foam comprising a silicone rubber binder and hollow glass beads, the silicone rubber syntactic foam partially or completely filling the open space of the battery module casing, and / or partially or completely covering the battery cells, and / or partially or completely covering the module casing and, optionally, a lid covering the battery module casing, and the silicone rubber syntactic foam is an addition-curable organopolysiloxane composition X. The publication discloses an addition-curable organopolysiloxane composition obtained by curing the above-mentioned organopolysiloxane composition, which comprises: a) at least one organopolysiloxane A having at least two silicon-bonded alkenyl groups per molecule, each of the alkenyl groups containing 2 to 14 carbon atoms; b) at least one silicon compound B having at least two silicon-bonded hydrogen atoms per molecule; c) hollow glass beads D; and d) a hydrosilylation catalyst C. However, the above-mentioned silicone rubber syntactic foam has the following problems: a. To achieve low density, a high content of hollow glass beads is required, whereas high hollow glass bead content leads to high viscosity and processing difficulties, so the density of syntactic foam cannot be consistently reduced, limiting its insulation during a thermal runaway event; and b. The lack of a cushion and the fact that the hollow glass beads cannot withstand significant deformation result in a low compressive strain, which is required to accommodate variations in the original thickness of the cell during assembly and to allow for thickness changes during the charge-discharge cycle of the cell. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent No. 10501597(B2) Summary of the Invention

[0007] Problems that the invention aims to solve The problem solved by the present invention is how to improve thermal insulation performance during thermal runaway and provide good cushioning performance while maintaining good processability. The concept of the present invention is a silicone-based fire protection material, preferably in the form of a sheet (pad) having a foam structure in which hollow fillers are bonded in a cellular silicone-based polymer foam, for use in battery packs. By including both cellular and hollow glass beads in the silicone rubber matrix, the cured and foamed composite can provide a better balance between thermal insulation performance, cushioning performance, and processability for EV battery pack applications.

[0008] Means to solve the problem As a result of extensive research, the present inventors have found that d 50 A silicone-based fire-resistant material having a foam structure in which hollow fillers of 10 to 200 microns are bonded, wherein the density of the silicone-based fire-resistant material is 0.1 g / cc to 0.8 g / cc, the Shore A hardness is 1 to 40, and the cell size d of the silicone-based polymer foam is 50 The present inventors have found that the above problems can be solved by using a silicone-based fireproof material having a particle size of 10 to 1000 microns, and have arrived at the present invention.

[0009] In the silicone-based fire-resistant material, the volume fraction of the hollow filler is 1 to 60% based on the total volume of the silicone-based fire-resistant material. In some embodiments of the present disclosure, the volume fraction of the air bubbles is 5 to 90% based on the total volume of the silicone-based fire-resistant material. In some embodiments of the present disclosure, the hollow filler is selected from hollow glass beads, aerogel particles, perlite beads, hollow ceramic beads, floating beads, and polymer hollow beads. In some embodiments of the present disclosure, the silicone-based polymer foam is obtained by curing a curable silicone-based composition comprising: a) at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; b) at least one silicone crosslinker having at least two, and optionally at least three, silicon-bonded hydrogen atoms per molecule; c) the hollow filler; d) a hydrosilylation catalyst; and e) a gas blowing agent. In some embodiments of the present disclosure, the curable silicone-based composition further comprises f) at least one additive selected from the group consisting of inhibitors that slow the cure rate, reactive diluents that react via a hydrosilylation reaction, pigments, dyes, clays, surfactants, hydrogenated castor oil, wollastonite, aluminum trihydrate, magnesium hydroxide, halloysite, huntite hydromagnesite, expandable graphite, zinc borate, mica, and fumed silica. In some embodiments of the present disclosure, the curable silicone-based composition further comprises g) at least one additive selected from the group consisting of flame retardant additives, curing catalysts, rheology modifiers, wetting additives, surface treatment agents, colorants, fillers other than hollow fillers, antioxidant additives, biocides, ultraviolet (UV) stabilizing additives, and adhesion promoter additives. In some embodiments of the present disclosure, the silicone-based fire-resistant material is applied to battery packages. In some embodiments of the present disclosure, the silicone-based fire-resistant material exhibits a compression set of 10% or more at 200 kPa.

[0010] The present disclosure further provides a battery packaging structure in which the silicone-based fire-retardant material is disposed completely or partially within the space between at least two adjacent individual battery cells. In some embodiments of the present disclosure, the battery cells are prismatic or pouch-shaped.

[0011] In the above battery packaging structure, the silicone-based fire-stop material is a silicone-based material that is cured before being placed in the space between at least two adjacent individual battery cells.

[0012] In some embodiments of the present disclosure, the silicone-based fire-protecting material is a cured silicone-based product through a curing reaction of a curable silicone-based composition in the space between at least two adjacent individual battery cells.

[0013] The present disclosure further provides a curable silicone-based composition that is formed into the silicone-based fire-stopping material through a curing reaction, comprising: a) at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; b) at least one silicone crosslinker having at least two, and optionally at least three, silicon-bonded hydrogen atoms per molecule; c) hollow fillers; d) a hydrosilylation catalyst; and e) a gas blowing agent; The present invention provides a curable silicone-based composition comprising:

[0014] In some embodiments of the present disclosure, the alkenyl groups each contain 2 to 14 carbon atoms. Optionally, the alkenyl group is selected from the group consisting of vinyl, allyl, hexenyl, decenyl, and tetradecenyl. Preferably, the alkenyl group is a vinyl group.

[0015] The present disclosure further provides a method for producing a silicone-based fire-stop material, the method comprising the steps of: Step (I): providing a Part A comprising: a) at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; and e) a gas blowing agent; Step (II): b) providing a Part B comprising at least one silicone crosslinker having at least two silicon-bonded hydrogen atoms per molecule, and optionally e) a gas blowing agent that is a physical blowing agent; Step (III): mixing Part A with Part B to form a curable silicone-based composition; Step (IV): Coating the curable silicone-based composition as a wet slurry layer onto a substrate, which optionally has a release layer; Step (V): A step of forming a silicone-based fire-protecting material by curing and foaming the coated curable silicone-based composition.

[0016] In some embodiments of the present disclosure, in step (IV), the thickness of the wet slurry layer of the curable silicone composition is in the range of 0.2 to 10.0 mm. The method for producing a silicone-based fire-resistant material further includes a step of controlling the viscosity and / or flowability of the curable silicone composition by adding a rheology control agent before or at the same time as step (IV).

[0017] The present invention further provides a method for producing a battery packaging structure, the method comprising the steps of: Step (BI): completely or partially filling the space between at least two adjacent individual battery cells with a curable silicone-based composition as a wet slurry; Step (B-II): A step of forming a silicone-based fire-protecting material in the space between at least two adjacent individual battery cells by curing and foaming the coated curable silicone-based composition.

[0018] Effect of the invention The present invention makes it possible to produce a silicone-based fire-resistant material, preferably a sheet, that exhibits a low density of 0.8 g / cc or less and a compression set of 10% or more at 200 kPa. According to the thermal insulation test described in this disclosure, the backside temperature of the silicone-based fire-resistant material is lower than that of a reference sample. Due to the relatively low loading of hollow filler to achieve the same or comparable density, the silicone-based fire-resistant material of the present invention exhibits better processability compared to, for example, prior art materials in which all of the voids are created by hollow filler and the viscosity is too high to process. In addition, the silicone-based fire-resistant material can be manufactured at a low temperature of 10 15 Ohms * It exhibits a high volume resistivity of over m.

[0019] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram of an apparatus for testing the thermal insulation performance of silicone-based fire protection materials according to the present disclosure. [Figure 2] FIG. 1 shows the backside temperature curve of Example IE-1 according to the present disclosure. [Figure 3] FIG. 1 illustrates air bubbles and hollow fillers in a silicone-based polymer foam according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. As disclosed herein, "and / or" means "and, or alternatively" or "in addition, or alternatively." All ranges include the endpoints unless otherwise indicated.

[0022] As used herein, the term "sheet" or "pad" refers to a flat product having a thickness in the form of a pad or sheet. In general, "sheet" or "pad" includes pad forms, sheet forms, and other flat forms of products having various thicknesses.

[0023] As used herein, the term "hollow filler" is understood to mean particles having a high density or low porosity shell and free space within the shell. The hollow filler according to the present invention has a shell whose thickness can be controlled.

[0024] As used herein, the term "thickness" refers to the average of at least three measurements of a dry sheet (e.g., a sheet having a thickness of 0.2 to 10.0 mm) as measured using an Ames Gage, Model 13C-B2600 (Ames Corporation, Waltham Massachusetts).

[0025] As used herein, the terms "aerogel" and "aerogel particles" describe a class of structures that have low density, open-cell structure, high surface area, and nanometer-scale pore sizes. Aerogel particles may be provided in at least one of the following forms: powders, granules, beads, and other suitable forms, and include inorganic, organic, and hybrid organic-inorganic compositions, or some combination of the above forms and / or compositions.

[0026] As used herein, the term "aerogel" refers to a gel obtained in a known manner by the sol-gel route after drying. This term encompasses both suitable aerogels obtained by supercritical drying of formed gels, as well as gels commonly called "xerogels" obtained by evaporative drying at atmospheric pressure. Xerogels are highly advantageous when considering large-scale production of the materials of the invention due to their low cost, while aerogels exhibit more advantageous technical properties but are more expensive to produce.

[0027] As used herein, the terms "polymer" or "macromolecule" refer to polymers made from one or more different monomers, such as copolymers, terpolymers, tetrapolymers, pentapolymers, and the like, alternatively, and may be random, block, graft, sequential, or gradient polymers.

[0028] As used herein, "d 50 The term "median particle / pore diameter" refers to a median particle / pore diameter that can be measured by sieving methods, e.g., "a d of 200 μm" 50 " means that 50% of the particles / pores of the hollow filler / bubbles have a particle / pore size of 200 μm or more, and 50% of the particles / pores of the hollow filler / bubbles have a particle / pore size of less than 200 μm.

[0029] To effectively mitigate thermal runaway in batteries, the present invention provides chemically or physically expanded silicone foams using hollow fillers selected from hollow glass beads, aerogel particles, perlite beads, floating beads, and polymer hollow beads, for example.

[0030] According to the present invention, the silicone-based fire-resistant material has a foam structure in which hollow fillers are bonded to a silicone-based polymer foam containing bubbles. The hollow fillers have a diameter of 10 to 200 microns, 10 to 150 microns, 10 to 100 microns, 10 to 50 microns, 50 to 200 microns, 50 to 150 microns, 50 to 100 microns, 100 to 200 microns, 100 to 150 microns, or 150 to 200 microns. 50The silicone-based fire-retardant material has a density of 0.1 g / cc to 0.8 g / cc, 0.1 g / cc to 0.6 g / cc, 0.1 g / cc to 0.4 g / cc, 0.1 g / cc to 0.2 g / cc, 0.2 g / cc to 0.8 g / cc, 0.2 g / cc to 0.6 g / cc, 0.2 g / cc to 0.4 g / cc, 0.4 g / cc to 0.8 g / cc, 0.4 g / cc to 0.6 g / cc, or 0.6 g / cc to 0.8 g / cc. The silicone-based fire-resistant material has a Shore A hardness of 1 to 40, 1 to 35, 1 to 30, 1 to 25, 1 to 20, 1 to 10, 1 to 5, 5 to 40, 5 to 35, 5 to 30, 5 to 25, 5 to 20, 5 to 10, 10 to 40, 10 to 35, 10 to 30, 10 to 25, 10 to 20, 20 to 40, 20 to 35, 20 to 30, 20 to 25, 30 to 40, 30 to 35, 25 to 35, or 35 to 40. Silicone polymer foam is available in sizes of 10-1000 microns, 10-800 microns, 10-600 microns, 10-400 microns, 10-200 microns, 10-100 microns, 10-50 microns, 50-1000 microns, 50-800 microns, 50-600 microns, 50-400 microns, 50-200 microns, 50-100 microns, 100-1000 microns, 100 Bubble sizes of up to 800 microns, 100-600 microns, 100-400 microns, 100-200 microns, 200-1000 microns, 200-800 microns, 200-600 microns, 200-400 microns, 400-1000 microns, 400-800 microns, 400-600 microns, 600-1000 microns, 600-800 microns, or 80-1000 microns 50 It has.

[0031] In the present invention, the hollow filler is at least one selected from hollow glass beads, aerogel particles, perlite beads, hollow ceramic beads, floating beads, and polymer hollow beads. In some embodiments, the hollow glass beads are hollow borosilicate glass microspheres.

[0032] In some embodiments, the hollow filler has a volume fraction of 1-60%, 1-50%, 1-40%, 1-30%, 1-20%, 1-10%, 1-5%, 5-60%, 5-50%, 5-40%, 5-30%, 5-20%, 5-10%, 10-60%, 10-50%, 10-40%, 10-30%, 10-20%, 20-60%, 20-50%, 20-40%, 20-30%, 30-60%, 30-50%, 30-40%, 40-60%, 40-50%, or 50-60%, based on the total volume of the silicone-based fire protection material. Alternatively, the hollow filler in the dry silicone-based fire-stop material has a loading of 1 vol% to 20 vol%, 1 vol% to 15 vol%, 1 vol% to 10 vol%, 1 vol% to 5 vol%, 5 vol% to 20 vol%, 5 vol% to 15 vol%, 5 vol% to 10 vol%, 10 vol% to 20 vol%, 10 vol% to 15 vol%, or 15 vol% to 20 vol%.

[0033] In some embodiments, the bubbles have a volume fraction of 5-90%, 5-50%, 5-40%, 5-30%, 5-20%, 5-10%, 10-60%, 10-50%, 10-40%, 10-30%, 10-20%, 20-60%, 20-50%, 20-40%, 20-30%, 30-60%, 30-50%, 30-40%, 40-60%, 40-50%, or 50-90%, based on the total volume of the silicone-based fire-stopping material.

[0034] In the present invention, aerogel particles can be provided in any suitable form, such as granules, powders, and beads. The chemical composition of the aerogel particles can be inorganic, organic, hybrid organic-inorganic, or any combination thereof. Any combination of the above forms and / or compositions can be used in the present invention. Optionally, the aerogel particles can be coated with one or more materials, such as a polymer or elastomer, or treated with a treating agent, such as a silane. A variety of different aerogel compositions can be used, including inorganic, organic, and hybrid organic-inorganic compositions. Inorganic aerogels are generally based on metal oxide compounds, including, but not limited to, silica, titania, zirconia, alumina, hafnia, yttria, or various carbides, nitrides, or any combination thereof. Organic aerogels can be based on compounds including, but not limited to, urethanes, resorcinol formaldehyde, polyimides, polyacrylates, chitosan, polymethyl methacrylate, members of the acrylate family of oligomers, trialkoxysilyl-terminated polydimethylsiloxanes, polyoxyalkylenes, polyurethanes, polybutadiene, members of the polyether family of materials, or combinations thereof. Examples of organic-inorganic hybrid aerogels include, but are not limited to, silica-PMMA, silica-chitosan, or combinations of the aforementioned organic and inorganic compounds. In certain circumstances, organic polymers or organic-inorganic hybrid polymers can be thermally treated to yield carbon- or inorganic-based mesoporous or microporous materials, including aerogels.

[0035] In the present invention, the silicone-based fire-resistant material may exhibit a compression set at 200 kPa of 10% or more, 15% or more, 20% or more, 25% or more, or 30% or more.

[0036] In an embodiment of the present disclosure, the silicone-based polymer foam comprises: a) at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; b) at least one silicone crosslinker having at least two or at least three silicon-bonded hydrogen atoms (Si—H or —SiH) per molecule; c) hollow fillers; d) a hydrosilylation catalyst; and e) a gas blowing agent; The silicone-based curable composition is obtained by curing the silicone-based curable composition.

[0037] In the present invention, component a) is well known in the art, examples of which include vinyl endblocked polydiorganosiloxanes (i.e., vinyl terminated PDMS) of the formula:

[0038] [ka] In the formula, R 3 and R 4 is selected from the group consisting of alkyl groups having 1 to 6 carbon atoms per group, phenyl groups, and vinyl groups; R 4 At least 50% of the groups are methyl groups. Preferably, the viscosity of component a) at 25°C is 8000 cst to 20000 cst, 8000 cst to 16000 cst, 8000 cst to 14000 cst, 8000 cst to 12000 cst, or 8000 cst to 10000 cst.

[0039] In some embodiments of the present disclosure, the alkenyl group included in component a) can contain 2 to 14 carbon atoms, 4 to 12 carbon atoms, or 6 to 10 carbon atoms; preferably, the alkenyl group is selected from the group consisting of vinyl, allyl, hexenyl, decenyl, and tetradecenyl; most preferably, the alkenyl group is a vinyl group.

[0040] Particularly preferably, component a) can be incorporated into the curable silicone-based composition in an amount of 20% to 80% by weight, 30% to 60% by weight, or 40% to 50% by weight, for example 30.1% by weight, based on the total amount of the curable silicone-based composition.

[0041] In the present invention, component b) can be used to adjust crosslink density and can be any silicone having an average of at least two silicon-bonded hydrogen atoms per molecule. The remaining valences of the silicon atoms are satisfied by divalent oxygen atoms or monovalent alkyl radicals having 1 to 6 carbon atoms per radical, such as methyl, ethyl, propyl, isopropyl, butyl, hexyl, and phenyl. The organohydrogensilicone can be a homopolymer, copolymer, or mixture thereof. Preferably, the organohydrogensilicone is a copolymer of trimethylsiloxy and methylhydrogensilicone, or a copolymer of trimethylsiloxy, methylhydrogensilicone, and dimethylsilicone. In an embodiment of the present invention, the organohydrogensilicone has an average of at least three silicon-bonded hydrogen atoms per molecule. In an embodiment of the present invention, component b) has a viscosity of 1 cst to 100 cst, 1 cst to 80 cst, 1 cst to 60 cst, 1 cst to 40 cst, or 1 cst to 20 cst at 25° C. In an embodiment of the present invention, component b) contains 1 to 5 wt %, 1 to 4 wt %, 1 to 3 wt %, 1 to 2 wt %, or 1 to 1.5 wt % SiH. In an embodiment of the present invention, component b) is a hydrogenated silicone oil having a viscosity of 20 cst at 25° C. and about 1.6 wt % SiH.

[0042] Particularly preferably, component b) can be incorporated into the curable silicone-based composition in an amount of 4% to 20% by weight, 6% to 16% by weight, or 8% to 14% by weight, for example 12% by weight, based on the total amount of the curable silicone-based composition.

[0043] In the present invention, component c) can be used to adjust the hardness and density of the silicone-based fire-resistant material. Hollow glass beads function to reduce the density of the foam. Hollow glass beads, particularly hollow glass microspheres, are well suited for this application because they have excellent isotropic compressive strength and the lowest density of any filler useful in producing high-compressive strength foams. The combination of high compressive strength and low density makes hollow glass microspheres a filler with numerous advantages according to the present invention. According to one embodiment, the hollow glass beads are hollow borosilicate glass microspheres, also known as glass bubbles or glass microbubbles. According to another embodiment, the hollow borosilicate glass microspheres have a true density ranging from 0.10 grams per cubic centimeter (g / cc) to 0.65 grams per cubic centimeter (g / cc).

[0044] According to a preferred embodiment, the hollow glass beads are selected from the 3M™ Glass Bubbles Floated series (A16 / 500, G18, A20 / 1000, H20 / 1000, D32 / 4500, and H50 / 10,000 EPX glass bubble products) and the 3M™ Glass Bubbles series (such as, but not limited to, K1, K15, S15, S22, K20, K25, S32, S35, K37, XLD3000, S38, S38HS, S38XHS, K46, K42HS, S42XHS, S60, S60HS, iM16K, iM30K glass bubble products) sold by 3M Company. The glass bubbles exhibit various crush strengths ranging from 1.72 megapascals (250 psi) to 186.15 megapascals (27,000 psi) at which 10 volume percent of the first plurality of glass bubbles collapse. Other glass bubbles sold by 3M, such as 3M™ Glass Bubbles—Floated series, 3M™ Glass Bubbles—HGS series, and 3M™ Glass Bubbles with Surface Treatment, can also be used in accordance with the present invention.

[0045] According to a preferred embodiment, the glass bubbles are selected from those exhibiting a crush strength ranging from 1.72 megapascals (250 psi) to 186.15 megapascals (27,000 psi) at which 10 volume percent of the first plurality of glass bubbles collapse. According to a most preferred embodiment, the hollow glass beads are selected from the 3M™ Glass Bubbles series, S15, K1, K25, iM16K, S32, and XLD3000.

[0046] Particularly preferably, component c) can be incorporated into the curable silicone-based composition in an amount of 1 wt. % to 15 wt. %, 3 wt. % to 10 wt. %, or 5 wt. % to 8 wt. %, for example 4.7 wt. %, based on the total amount of the curable silicone-based composition.

[0047] In the present invention, the hydrosilylation catalyst of component d) can be selected from the group consisting of platinum, palladium, rhodium, nickel, iridium, ruthenium catalysts, and mixtures thereof, and is preferably a platinum catalyst, which can efficiently promote the reaction of -SiH groups with vinyl groups and the reaction of -SiH groups with hydroxyl groups to provide hydrogen gas for the foaming process. Particularly preferred is a two-component foamable silicone composition in which the catalyst is an organoplatinum compound. Particularly preferred is a two-component foamable silicone composition in which the catalyst is a functional organoplatinum compound selected from (η-diolefin)(α-aryl)platinum complexes, (η-diolefin)(γ-aryl)platinum complexes, (η-diolefin)(γ-alkyl)platinum complexes, and mixtures thereof. Commercially available products can be used in the present invention.

[0048] Particularly preferably, component d) can be incorporated into the curable silicone-based composition in an amount of 0.1 wt. % to 2 wt. %, 0.5 wt. % to 1.5 wt. %, or 0.8 wt. % to 1.3 wt. %, for example 1.2 wt. %, based on the total amount of the curable silicone-based composition.

[0049] In the present invention, component e) may comprise a chemical blowing agent, a physical blowing agent, or a mixture of a chemical blowing agent and a physical blowing agent. The curable silicone-based composition may be mechanically foamed or may comprise a chemical and / or physical blowing agent. To avoid the generation of explosive gases and / or volatile organic compounds, the use of suitable physical blowing agents may be utilized, including those that are non-flammable and / or inert gases at 0°C (zero°C).

[0050] Alternatively, component e) may comprise a physical liquid blowing agent. When component e) is a physical liquid blowing agent, the physical liquid blowing agent is adapted to undergo a phase change at the application temperature. When component e) is a physical blowing agent, the phase change at the application temperature is the primary source of gas that results in foam formation by replacing all or most of the hydrogen gas generated when a chemical blowing agent is used.

[0051] When component e) is a physical blowing agent, the selected physical blowing agent is selected according to its boiling point so as to undergo a phase change from a liquid to a gaseous state during exposure to atmospheric pressure and the temperatures of the curing process, for example, temperatures of 10° C. or less, alternatively 20° C. or less, alternatively 30° C. or less, alternatively 40° C. or less, alternatively 50° C. or less, alternatively 60° C. or less, alternatively 70° C. or less, alternatively 80° C. or less, alternatively 90° C. or less, or alternatively 100° C. For room temperature vulcanization systems, the selected physical blowing agent may have a boiling point of 10-30° C., i.e., so as to undergo a phase change from a liquid to a gaseous state during exposure to atmospheric pressure within this temperature range.

[0052] When component e) is a physical blowing agent, the amount of physical blowing agent utilized can be varied depending on the desired results, for example, the amount of physical blowing agent can be varied to adjust the final foam density and foam rise profile of the resulting insulation.

[0053] Useful physical blowing agents include hydrocarbons in liquid form, such as pentane, hexane, halogenated, more particularly chlorinated and / or fluorinated hydrocarbons, such as methylene chloride, chloroform, trichloroethane, chlorofluorocarbons, hydrochlorofluorocarbons (HCFCs), ethers, ketones, and esters, such as methyl formate, ethyl formate, methyl acetate, or ethyl acetate, or air, nitrogen, or carbon dioxide as a gas. In certain embodiments, the physical blowing agent comprises a compound selected from the group consisting of propane, butane, isobutane, isobutene, isopentane, dimethyl ether, or mixtures thereof. In many embodiments, the blowing agent comprises an inert compound.

[0054] In various embodiments, the physical blowing agent comprises a hydrofluorocarbon (HFC). "Hydrofluorocarbon" and "HFC" are interchangeable terms and refer to organic compounds containing hydrogen, carbon, and fluorine, which are substantially free of halogens other than fluorine.

[0055] Examples of suitable HFCs include aliphatic compounds such as 1,1,1,3,3-pentafluoropropane, 1,1,1,3,3-pentafluorobutane, 1-fluorobutane, nonafluorocyclopentane, perfluoro-2-methylbutane, 1-fluorohexane, perfluoro-2,3-dimethylbutane, perfluoro-1,2-dimethylcyclobutane, perfluorohexane, perfluoroisohexane, perfluorocyclohexane, perfluoroheptane, perfluoroethylcyclohexane, perfluoro-1,3-dimethylcyclohexane, and perfluorooctane; and aromatic compounds such as fluorobenzene, 1,2-difluorobenzene; 1,4-difluorobenzene, 1,3-difluorobenzene; 1,3,5-trifluorobenzene; 1,2,4,5-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,3,4-tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene, and 1-fluoro-3-(trifluoromethyl)benzene. In certain embodiments, compounds such as 1,1,1,3,3-pentafluoropropane and 1,1,1,3,3-pentafluorobutane may be preferred due to their increased availability and ease of use, with 1,1,1,3,3-pentafluorobutane having a higher boiling point than 1,1,1,3,3-pentafluoropropane, which may be useful in certain applications. For example, HFCs with boiling points above 30°C, such as 1,1,1,3,3-pentafluorobutane, may be desirable because they do not require liquefaction during foam processing. In certain embodiments, when component e) is a physical blowing agent, component e) comprises 1,1,1,3,3-pentafluoropropane.

[0056] When component (e) includes a chemical blowing agent, it contains one or more hydroxyl-containing blowing agents that react with crosslinker (b) in the presence of component (d), a catalyst. When component (e) is a chemical blowing agent containing one or more hydroxyl-containing blowing agents, each hydroxyl-containing blowing agent contains at least one hydroxyl (OH) group, alternatively at least two OH groups, alternatively three or more OH groups. The OH group(s) can react with the Si-H groups of component (b), thereby generating hydrogen gas and thereby producing foam. Each hydroxyl-containing blowing agent can be a suitable alcohol. These can be selected from aliphatic organic alcohols having 1 to 12 carbon atoms, such as methanol, ethanol, propanol, isopropanol, etc., or low molecular weight alcohols, including, but not limited to, benzyl alcohol.

[0057] In one embodiment, the hydroxyl-containing blowing agent may be a diol. Examples of suitable diols include, but are not limited to, methylene glycol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, bisphenol A, 1,4-butanediol, 1,3-propanediol, 1,5-pentanediol, 1,7-heptanediol, 1,2-hexanediol, triethylene glycol, tripropylene glycol, neopentyl glycol, and combinations thereof. Alternatively, the hydroxyl-containing blowing agent may be a triol.

[0058] In various embodiments, component e) is a chemical blowing agent, selected from the group of low-boiling alcohols. Most (but not all) of these alcohols have boiling points below about 120°C. The alcohol may or may not be anhydrous, although anhydrous alcohols (containing less than 1% water by weight) based on the weight of the alcohol are generally preferred. Other suitable blowing agents are described in U.S. Pat. No. 4,550,125, U.S. Pat. No. 6,476,080, and U.S. Patent Application Publication No. 20140024731, which are incorporated herein by reference.

[0059] Component e), when a hydroxyl-containing blowing agent, is present in an amount to provide an OH content of from about 10 parts per million (ppm) to 50,000 ppm, alternatively from about 100 ppm to 20,000 ppm, alternatively from about 500 ppm to 10,000 ppm, alternatively from about 500 to about 7500 ppm.

[0060] In other embodiments, when component e) is a chemical blowing agent, the chemical blowing agent may be selected from the group of Si-OH polymers. In certain embodiments, when component e) is a chemical blowing agent, it is selected from the group consisting of organosilanes and organosiloxanes having at least one silanol (Si-OH) group. Such compounds may have a structure similar to the polymers described above for component (a).

[0061] Examples of suitable OH-functional compounds include dialkylsiloxanes, such as OH-terminated dimethylsiloxane. Such siloxanes may have relatively low viscosities, such as about 15 to about 20,000 mPa s, about 15 to about 10,000 mPa s, about 15 to about 5,000 mPa s, about 15 to about 1,000 mPa s, or about 15 to about 100 mPa s, measured at 25°C. Viscosity is measured using either a Brookfield™ rotational viscometer with spindle LV-3 (designed for viscosities in the range of -200 to 400,000 mPa s) or a Brookfield™ rotational viscometer with spindle LV-1 (designed for viscosities in the range of 15 to 20,000 mPa s) for viscosities below 200 mPa s, and the speed, i.e., shear rate, is determined according to the polymer viscosity, e.g., from 0.005 s -1 ~1s -1 (0.3 to 60 rpm) (in this case 1 s -1 (preferably 0.15°C) and measured at 25°C.

[0062] In another embodiment of the present invention, component e) may have at least one hydroxyl group, including one, two, or more hydroxyl groups, or is a mixture of compounds having at least one hydroxyl group. The hydroxyl groups of component e) can react with the silicon-hydrogen (SiH) groups of the silicone having at least two -SiH groups (hydrosilyl groups) to produce hydrogen gas, thereby creating bubbles in the foam. In some embodiments of the present disclosure, component e) is selected from silanols, alcohols, water, and mixtures thereof.

[0063] In one embodiment of the present disclosure, the alcohol may have 1 to 12 carbon atoms. Examples of alcohols include methanol, ethanol, propanol, isopropanol, butanol, and the like. The alcohol can react with hydrogen atoms on silicon in the presence of a platinum catalyst to generate additional hydrogen gas. Preferably, the alcohol is a monohydroxyl alcohol. When a monohydroxyl alcohol is used, the corresponding crosslinks are not formed, so the resulting foam tends to be less crosslinked than when the alcohol is absent. Foams formed by using alcohol tend to have lower densities than when the alcohol is absent.

[0064] Particularly preferably, component e) can be incorporated into the curable silicone-based composition in an amount of 0.1 wt. % to 5 wt. %, 0.5 wt. % to 3 wt. %, or 1.0 wt. % to 2 wt. %, for example 1.9 wt. %, based on the total amount of the curable silicone-based composition.

[0065] In some embodiments of the present disclosure, the curable silicone-based composition comprises: f) further comprising at least one additive selected from inhibitors that slow the rate of cure, reactive diluents that react via a hydrosilylation reaction, pigments, dyes, clays, surfactants, hydrogenated castor oil, wollastonite, aluminum trihydrate, magnesium hydroxide, halloysite, huntite hydromagnesite, expandable graphite, zinc borate, mica, and fumed silica.

[0066] In some embodiments of the present disclosure, the curable silicone-based composition comprises: g) further comprising at least one selected from the group consisting of a flame retardant additive, a curing catalyst, a rheology modifier, a wetting additive, a surface treatment agent, a colorant, a filler other than hollow fillers, a hydrosilylation catalyst inhibitor, a foaming promoter, an antioxidant additive, a biocide, a reinforcing resin, an ultraviolet (UV) stabilizing additive, and an adhesion promoting additive.

[0067] In the present invention, the flame retardancy of the silicone-based fire-resistant material can be further improved by adding a flame-retardant additive. Generally, the amount of the flame-retardant additive is 0 to 40 weight percent, 10 to 30 weight percent, or 15 to 25 weight percent, depending on the flame-retardant requirements of the silicone-based fire-resistant material. The flame-retardant additive may include non-combustible fibers and sulfur-free carbon black. The non-combustible fibers are believed to help retain the char formed when the foam is exposed to flame, protecting the foam below the charred surface. The non-combustible fibers may be selected from fibers such as carbon fibers, ceramic fibers, and aramid fibers, with ceramic fibers being preferred. The fibers should be fine fibers with an average diameter of less than 5 micrometers and a length of less than 100 millimeters so that they can be uniformly and easily distributed throughout the mixture. Preferably, 1 to 5 weight percent of the non-combustible fibers and 1 to 5 weight percent of the sulfur-free carbon black are present. The added carbon black may be any of the conventional sulfur-free carbon blacks used as additives in silicone elastomers cured with platinum catalysts. The carbon black does not contain sulfur, as sulfur can interfere with curing.

[0068] In some embodiments of the present disclosure, the flame-retardant additive comprises a halogenated flame-retardant additive and / or a non-halogenated flame-retardant additive. Examples of the halogenated flame-retardant additive include brominated polymers or oligomers, brominated styrene-butadiene-styrene copolymers, and the like, preferably a combination of a brominated flame-retardant additive and antimony trioxide to form a Br-Sb synergistic system. Examples of non-halogenated flame-retardant additives include ammonium polyphosphate, melamine polyphosphate, aluminum hydroxide, magnesium hydroxide, and expandable graphite. In the present invention, the flame-retardant additive may be dispersed in or distributed throughout the silicone-based polymer binder (i.e., the polymer matrix) at a loading ranging from 0 to 60% by weight of the dry material. Flame-retardant additives with loadings greater than 60% by weight may result in insufficient thermal insulation performance, as required for battery fire protection applications.

[0069] In the present invention, the (hydrosilylation catalyst) inhibitor can slow the reaction rate, allowing mixing to be completed before the mixture begins to form bubbles. Examples of hydrosilylation catalyst inhibitors include methylvinylcyclosiloxane, tetravinyltetramethylcyclotetrasiloxane (vinyl D4), ethynylcyclohexanol (ECH), and mixtures thereof. Particularly preferably, the hydrosilylation catalyst inhibitor is incorporated into the curable silicone composition in an amount of 0 to 2 wt %, 0.5 to 1.5 wt %, or 0.8 to 1.2 wt %, for example, 0.7 wt %, based on the total amount of the curable silicone composition, depending on the desired cure rate.

[0070] Fillers other than hollow fillers include, but are not limited to, (fumed) silica, diatomaceous earth, crushed quartz, zinc oxide, huntite, aluminum hydroxide, CaCO3, and hydromagnesite, fibrous potassium titanate, or other well-known fillers for silicone-based fire protection materials. The maximum amount of filler other than hollow fillers used depends on the viscosity of the curable silicone-based composition.

[0071] In the present invention, a foaming accelerator may be used to adjust the morphology of the foam being formed, resulting in a modified foam with smaller, more uniform cells, preferably primarily closed cells, and allowing the production of foams with different combinations of properties such as density, compressibility, and resilience. The foaming accelerator comprises a resinous, benzene-soluble organosiloxane copolymer, the repeating unit of which is SiO 4 / 2 Units, (CH 3)3 SiO 1 / 2 The fluorine-containing unit includes, but is not limited to, a fluorine-containing unit having at least one perfluorinated carbon atom, and a fluorine-containing unit having at least one perfluorinated carbon atom. Each of the fluorine-containing units also includes one or two silicon atoms connected to the fluorine-containing carbon atom by a sequence of at least two methylene (-CH2-) units, or by an oxygen atom connected to the sequence. The foaming accelerator includes, for example, a fluorinated silicone resin.

[0072] Particularly preferably, the foaming accelerator may be incorporated into the curable silicone-based composition in an amount of 0% to 10% by weight, 3% to 8% by weight, or 5% to 6% by weight, for example 7.5% by weight, based on the total amount of the curable silicone-based composition, depending on the desired cure rate.

[0073] The reinforcing resin can improve mechanical requirements, examples of which include a blend of PDMS and resin, where the amount of resin is 35 wt %, and 0.84 wt % vinyl, and the blend has a viscosity of 5000 cst at 25° C. Particularly preferably, the reinforcing resin can be incorporated into the curable silicone-based composition in an amount of 0 wt % to 50 wt %, 10 wt % to 40 wt %, or 20 wt % to 30 wt %, for example 30.4 wt %, based on the total amount of the curable silicone-based composition.

[0074] Rheology modifiers are used to fine-tune the viscosity of the wet slurry, typically in amounts of 0-2% by weight. Curing catalysts include dioctyltin dilaurate and other additives, depending on the curing chemistry. Wetting additives are used to wet the surface of hydrophobic fillers. Colorants can impart desired colors to silicone-based fire-resistant materials.

[0075] In the present invention, the method for producing the silicone-based fire-retardant material includes the following steps: Step (I): providing a Part A comprising: a) at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; and e) a gas blowing agent; Step (II): b) providing a Part B comprising at least one silicone crosslinker having at least two silicon-bonded hydrogen atoms per molecule, and optionally e) a gas blowing agent that is a physical blowing agent; Step (III): mixing Part A with Part B to form a curable silicone-based composition; Step (IV): Coating the curable silicone-based composition as a wet slurry layer onto a substrate, which optionally has a release layer; Step (V): A step of forming a silicone-based fire-protecting material by curing and foaming the coated curable silicone-based composition.

[0076] In some embodiments of the present disclosure, components (a)-(g) can be combined in any combination to create two parts for storage, as long as the chemical blowing agent and alkenyl-containing organopolysiloxane as gas blowing agents are not present together with the Si-H-containing silicone crosslinker. For best shelf life, it is desirable not to have the hydrosilylation catalyst and organopolysiloxane in the same package. In some embodiments of the present disclosure, components c), d), f), and g) can be added independently to Part A, Part B, or both. When a physical blowing agent is utilized as a gas blowing agent in the method for producing the silicone-based fire protection material of the present invention, it can be incorporated into Part A, Part B, or both.

[0077] In an embodiment of the present invention, the method of producing the silicone-based fire-resistant material may further include adding a flame retardant additive, a cure catalyst, a rheology modifier, a wetting additive, a surface treatment agent, a colorant, a filler other than hollow fillers, an antioxidant additive, a biocide, an ultraviolet (UV) stabilizer additive, and an adhesion promoter additive to Part A, Part B, or both, before combining Part A with Part B.

[0078] In an embodiment of the present invention, the method of producing the silicone-based fire-resistant material may further include adding a flame retardant additive, a cure catalyst, a rheology modifier, a wetting additive, a surface treatment agent, a colorant, a filler other than hollow fillers, an antioxidant additive, a biocide, an ultraviolet (UV) stabilizer additive, and an adhesion promoter additive to the curable silicone-based composition after combining Part A with Part B.

[0079] In an embodiment of the present invention, the method for producing the silicone-based fire-resistant material may further include, in step (IV), having the wet slurry layer of the curable silicone-based composition have a thickness of 0.2 to 10.0 mm, 0.2 to 6.0 mm, 0.2 to 2.0 mm, 0.2 to 1.0 mm, 1.0 to 10.0 mm, 1.0 to 6.0 mm, 1.0 to 2.0 mm, 2.0 to 10.0 mm, 2.0 to 6.0 mm, or 6.0 to 10.0 mm.

[0080] In an embodiment of the present invention, the method for producing the silicone-based fire-protecting material may further comprise, prior to or at the same time as step (IV), a step of controlling the viscosity and / or flowability of the curable silicone-based composition with a rheology modifier.

[0081] In embodiments of the present invention, the method of producing the silicone-based fire-resistant material may further include removing the silicone-based fire-resistant material from the substrate, such as a release paper.

[0082] In the present invention, the silicone-based fire-retardant material may be used in a secondary battery pack including at least one battery module casing, the casing including a plurality of battery cells electrically connected to each other, the preferred shape of the battery cells being prismatic or pouch-shaped, and preferably protected by the silicone-based fire-retardant material.

[0083] In an embodiment of the present invention, a battery packaging structure is described in which the silicone-based fire-retardant material is completely or partially disposed in the space between at least two adjacent individual battery cells. When preparing the battery packaging structure, the silicone-based fire-retardant material may be cured before being disposed in the space between at least two adjacent individual battery cells. In the method for producing this battery packaging structure, the "cured" silicone-based fire-retardant material may be completely or partially disposed (including inserted) in the space between at least two adjacent individual battery cells to prevent heat transfer from the hot surface of the "ignited" cell to adjacent good cells caused by thermal runaway propagation.

[0084] Alternatively, the silicone-based fire-resistant material can be disposed in the space between at least two adjacent individual battery cells through a curing reaction of the curable silicone-based composition in the space. In this embodiment of the present invention, the battery packaging structure is prepared using a curable silicone-based composition that can be cured to become the silicone-based fire-resistant material. More specifically, the method for producing this battery packaging structure includes the following steps: step (BI): completely or partially filling the space between at least two adjacent individual battery cells with the curable silicone-based composition of claim 13 or 14 as a wet slurry layer, and step (B-II): forming the silicone-based fire-resistant material in the space between at least two adjacent individual battery cells by curing and foaming the curable silicone-based composition.

[0085] Taking into consideration the procedural requirements in the battery assembly process or the fire protection performance required for the battery packaging structure, any of the production methods can be used to place a silicone-based fire protection material in the space between at least two adjacent individual battery cells.

[0086] The silicone-based fire-resistant material partially or completely fills the open space of the battery module casing, partially or completely covers the battery cells, and / or partially or completely covers the module casing, and optionally covers a lid that covers the battery module casing. The silicone-based fire-resistant material is obtained by dispersing hollow fillers in a silicone-based polymer foam, coating it to a specific wet thickness, and forming the final material using the hollow fillers and air bubbles. The silicone-based fire-resistant material may be assembled between the water-cooled plate and the metal plate of the battery case to prevent heat diffusion between the water-cooled plate and the metal plate of the battery case. The silicone-based fire-resistant material of the present invention can be manufactured into standard parts and then assembled into the battery case. The silicone-based fire-resistant material of the present invention can also be manufactured by dispersing hollow fillers in a liquid silicone composite to obtain a wet slurry, which is then incorporated into the cavities between cells in the battery case to form the final cured foam material. [Example]

[0087] Some embodiments of the present invention are now described in the following examples, in which all parts and percentages are by weight unless otherwise specified.

[0088] Information on the raw materials used in the examples is listed in Table 1 below.

[0089] [Table 1]

[0090] Inventive Examples 1-2 (IE1-2) and Comparative Examples 1-2 (CE1-2) In Inventive Examples 1-2 of the present disclosure, silicone-based fire-resistant materials were prepared using the raw materials and their amounts set forth in Table 2. Comparative Examples 1-2 served as controls.

[0091] Table 2: Formulations used in the examples and comparative examples

[0092] [Table 2]

[0093] [Table 3]

[0094] For IE1-2 and CE1-2, six steps were included: Step 1: Formulating Part A as a wet slurry; Step 2: Formulating Part B as a wet slurry; Step 3: Mixing Part A with Part B to form a curable silicone-based composition as a mixed wet slurry; Step 4: Coating the mixed wet slurry onto a substrate having a release layer; Step 5: curing and foaming the mixed wet slurry to form a silicone-based fire-stop material; and Step 6: Testing the thermal insulation performance of silicone fire protection materials at high temperatures.

[0095] A detailed description of steps 1 to 6 is given below: Step 1: Blend Part A P-1, R-1, CAT-1, INH-1 (if needed), B-1, and PF-1 (if needed) were added to a 1-liter plastic cup and mixed at a stirring speed of 300 rpm using a Cowles blade to form a homogeneous slurry. F-1 was then slowly added while stirring at 300 rpm to ensure dissolution and avoid clumping. After complete dispersion and viscosity increase, F-2 and / or F-3 (if needed) were gradually added while stirring at 300 rpm to create a homogeneous slurry.

[0096] Step 2: Blend Part B P-1, R-1, and CX-1 were added to a 1-liter plastic cup and mixed at 300 rpm using a Cowles blade to form a homogeneous slurry. F-1 was then slowly added while stirring at 300 rpm to ensure dissolution and avoid clumping. After complete dispersion and viscosity increase, F-2 and / or F-3 (as needed) were gradually added while stirring at 300 rpm to create a homogeneous slurry.

[0097] Step 3: Mix Part A with Part B Part A was mixed with Part B while stirring at 300 rpm to create a homogenous slurry.

[0098] Step 4: Coat the wet slurry onto a substrate The slurry obtained in step 3 was coated onto a PTFE sheet with a knife doctor to form a wet sheet of 1 mm thickness.

[0099] Step 5: Hardening and foaming of the mixed wet slurry The wet sheet obtained in step 4 was dried in an oven at 90°C for 1 hour to obtain a dry sheet.

[0100] Step 6: Testing insulation performance at high temperatures.

[0101] The dried sheet was cut into an 8 cm x 8 cm square and placed on a heat stage stabilized at 600 °C. An Al plate with two 0.5 mm OD K-type thermocouples was attached to the backside of the specimen, partially embedded in 0.4 mm grooves, in close contact with the specimen's backside to record the backside temperature. To control heat diffusion, the entire surface of the Al plate was thoroughly covered with insulating asbestos board. A steel load was then placed on the Al plate to apply a 0.03 MPa pressure to the specimen. See Figure 1 for a schematic of the setup. The entire setup was completed within 10 seconds of attaching the specimen to the heat stage. The 600 °C heat stage temperature was calibrated by placing an 8 cm x 8 cm square aerogel sheet / pad with a thickness of 4 ± 0.2 mm on the Al plate, with one thermocouple directly in contact with the heat stage surface at the center of the sheet. Calibration continued for at least 20 minutes with the heat stage surface stabilized at 600 °C before starting the thermal insulation performance test. During the test, the rear surface temperature was recorded from the time the specimen was attached to the heat stage. The test lasted for 20 minutes. The original thickness of the sheet specimen was measured at each corner, and the average thickness was calculated. During the test, a feeler gauge was used to insert between the heat stage and the Al plate, and the thickness was measured just before the end of the test. The change in rear surface temperature with test time was recorded.

[0102] [Table 4]

[0103] Compared to CE1, which does not contain a blowing agent, both IE1 and IE2 of the present invention exhibit lower density and superior thermal insulation performance. Viscosity is about 16000 mPa * s, which was highly suitable for roll-to-roll casting and potting processes. Furthermore, the thermal insulation performance and flame retardancy were also significantly improved. Due to the presence of a specific volume fraction of bubbles, the compressive strain at 200 kPa met the requirements for battery pack applications with prismatic or pouch cells.

[0104] CE1 contained approximately 10% hollow glass beads, which significantly increased the viscosity of the curable silicone-based composition. CE1 had a density of 0.8 g / cc, which was higher than IE1 and IE2 of the present invention. Insulation testing showed that the backside temperature of CE1 reached 231.4°C, close to the critical temperature (250°C) that can cause thermal runaway in adjacent battery cells. CE1's compressive strain at 200 kPa was only 7.97%, lower than the minimum requirement for accommodating thickness variations in prismatic cells during module or pack assembly.

[0105] CE2 was an H2-blown silicone foam without hollow glass beads. The foam had low density and hardness. However, it was easily compressed during the thermal insulation performance test, resulting in poor thermal insulation performance.

[0106] IE1 and IE2 contained less than 5% by volume of hollow glass beads, and their viscosities were much lower. This was because the 1-propanol blowing agent reacted with the Si-H crosslinker and released H gas, which created a large amount of pores / voids during the curing process. Although the densities of IE1 and IE2 were lower, IE1 and IE2 had higher hardness, which enabled them to have low thermal conductivity and suitable cushioning performance, making them better suited for thermal barrier applications between individual cells in a battery pack.

[0107] Testing and Evaluation viscosity The viscosity of the curable silicone composition was measured according to ASTM D1084.

[0108] density The density of the silicone fire-stop material was measured according to ASTM D792.

[0109] Hardness (Shore A) The hardness of the silicone-based fire-resistant material was measured in accordance with ASTM D 2240.

[0110] Flame retardant The flame retardancy of silicone-based fire-resistant materials was measured in accordance with UL 94.

[0111] Insulation (rear temperature °C) Figure 1 shows the experimental setup for the thermal insulation performance test. 2 The sample was placed on a heater at 600°C for 20 minutes. Two thermocouples were placed on the backside of the sample to monitor the temperature. An aluminum block was placed on top of the sample to mimic adjacent battery cells in a battery module. Several iron blocks were added on top of the aluminum block to mimic the pressure (0.03 MPa) during the thermal runaway process.

[0112] Electrical insulation The dielectric strength of the silicone-based fire-resistant materials was measured in accordance with ASTM D 149, and the volume resistivity was measured in accordance with ASTM D257.

[0113] Hollow filler volume fraction The volume fraction of the hollow filler was calculated by the following formula. R 体積 =R 重量 ×ρ フォーム / ρ 中空充填剤 R 体積 is the volume fraction of hollow filler, and R 重量 is the weight fraction of hollow filler, and ρ フォーム is the density of the foam and ρ 中空充填剤 is the density of the hollow filler.

[0114] bubble volume fraction The volume fraction of bubbles was calculated using the following formula. R 気体 =1-R 体積 -(1-R 重量 )×ρ フォーム / ρ スラリー R 気体 is the volume fraction of bubbles, and R 体積 is the volume fraction of hollow filler, and R 重量 is the weight fraction of hollow filler, and ρ フォーム is the density of the foam and ρ スラリーis the density of the uncured formulation without hollow filler, which is 1.1 g / cc for the example formulation.

[0115] Compression strain The compressive strain is measured by Instron 5566. The size of the test piece is 36 mm x 36 mm x 3.4 mm, and the compression speed is controlled at 1 mm / min.

Claims

1. In a silicone polymer foam containing bubbles, ５０ A silicone-based fire-resistant material having a foam structure to which hollow fillers of 10 to 200 microns are bonded, wherein the density of the silicone-based fire-resistant material is 0.1 g / cc to 0.8 g / cc, the Shore A hardness is 1 to 40, and the cell size d of the silicone-based polymer foam is ５０ A silicone-based fire-retardant material having a particle size of 10 to 1000 microns.

2. 2. The silicone-based fire-resistant material according to claim 1, wherein the volume fraction of the hollow filler is 1 to 60% based on the total volume of the silicone-based fire-resistant material.

3. 2. The silicone-based fire-resistant material according to claim 1, wherein the volume fraction of the bubbles is 5 to 90% based on the total volume of the silicone-based fire-resistant material.

4. 2. The silicone-based fire-resistant material according to claim 1, wherein the hollow filler is selected from hollow glass beads, aerogel particles, perlite beads, hollow ceramic beads, floating beads, and polymer hollow beads.

5. The silicone polymer foam is obtained by curing a curable silicone composition, and the curable silicone composition comprises: a) at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; b) at least one silicone crosslinker having at least two silicon-bonded hydrogen atoms per molecule; c) a hollow filler; d) a hydrosilylation catalyst; and e) a gas blowing agent; 2. The silicone-based fire-resistant material of claim 1, comprising:

6. The curable silicone composition comprises:

6. The silicone-based fire-resistant material of claim 5, further comprising at least one additive selected from the group consisting of inhibitors that slow down the cure rate, reactive diluents that react via a hydrosilylation reaction, pigments, dyes, clays, surfactants, hydrogenated castor oil, wollastonite, aluminum trihydrate, magnesium hydroxide, halloysite, huntite hydromagnesite, expandable graphite, zinc borate, mica, and fumed silica.

7. The curable silicone composition comprises: g) at least one selected from the group consisting of flame retardant additives, curing catalysts, rheology modifiers, wetting additives, surface treatment agents, colorants, fillers other than hollow fillers, antioxidant additives, biocides, ultraviolet (UV) stabilization additives, and adhesion promoter additives.

8. The silicone-based fire-retardant material according to any one of claims 1 to 7, which is applied to a battery package.

9. The silicone-based fireproof material according to any one of claims 1 to 7, which has a compressive strain of 10% or more at 200 kPa.

10. A battery packaging structure, wherein the silicone-based fire-retardant material according to any one of claims 1 to 9 is disposed completely or partially within the space between at least two adjacent individual battery cells.

11. 11. The battery packaging structure of claim 10, wherein the battery cells are selected from prismatic cells and pouch cells.

12. 11. The battery packaging structure of claim 10, wherein said silicone-based fire-blocking material is a silicone-based material that is cured before being placed in the space between said at least two adjacent individual battery cells.

13. The silicone-based fire-protecting material is a cured silicone-based product obtained through a curing reaction of a curable silicone-based composition in the space between the at least two adjacent individual battery cells, and the curable silicone-based composition is a) at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; b) at least one silicone crosslinker having at least two silicon-bonded hydrogen atoms per molecule; c) a hollow filler; d) a hydrosilylation catalyst; and e) a gas blowing agent; 11. The battery packaging structure of claim 10, comprising:

14. A curable silicone-based composition that is formed into the silicone-based fire-resistant material according to any one of claims 1 to 9 through a curing reaction, comprising: a) at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; b) at least one silicone crosslinker having at least two silicon-bonded hydrogen atoms per molecule; c) a hollow filler; d) a hydrosilylation catalyst; and e) a gas blowing agent; 1. A curable silicone-based composition comprising:

15. The curable silicone-based composition of claim 14, wherein the alkenyl groups each contain from 2 to 14 carbon atoms.

16. A method for producing the silicone-based fire-protecting material according to any one of claims 1 to 9, comprising the steps of: Step (I): a) providing a Part A comprising at least one organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule and e) a gas blowing agent; Step (II): b) providing a Part B comprising at least one silicone crosslinker having at least two silicon-bonded hydrogen atoms per molecule, and optionally e) a gas blowing agent that is a physical blowing agent; Step (III): Mixing Part A with Part B to form the curable silicone-based composition of any one of claims 14 to 15; Step (IV): Coating the curable silicone-based composition as a wet slurry layer onto a substrate, which optionally has a release layer; Step (V): forming a silicone-based fire-stop material by curing and foaming the coated curable silicone-based composition.

17. 17. The method for producing a silicone-based fire-retardant material according to claim 16, wherein in step (IV), the thickness of the wet slurry layer of the curable silicone-based composition is 0.2 to 10.0 mm.

18. 17. The method for producing a silicone-based fire-resistant material according to claim 16, further comprising the step of controlling the viscosity and / or flowability of the curable silicone-based composition by adding a rheology modifier prior to or simultaneously with step (IV).

19. 11. A method of producing the battery packaging structure of claim 10, comprising the step of disposing the silicone-based fire-stop material of any one of claims 1 to 8 completely or partially in the space between at least two adjacent individual battery cells.

20. 11. A method for producing the battery packaging structure of claim 10, comprising: Step (BI): completely or partially filling the space between at least two adjacent individual battery cells with the curable silicone-based composition according to any one of claims 14 to 15 as a wet slurry layer; Step (B-II): forming a silicone-based fire-protecting material in the space between the at least two adjacent individual battery cells by curing and foaming the curable silicone-based composition.

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