Insulating multilayer sheet, method of manufacture, and articles using the same

Abstract

An insulating multilayer sheet for preventing thermal runaway includes a non-porous elastomeric barrier layer having a first surface and a second opposing surface; a flexible foam layer disposed on the first surface of the barrier layer; and a flame retardant component, where the flame retardant component is distributed within the flexible foam layer, in contact with a surface of the flexible foam layer, or both.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the interests of U.S. Patent Application No. 63 / 137,838, filed on 15 January 2021, which is incorporated herein by reference in its entirety. [Background technology]

[0002] This application relates to a multilayer thermal insulation sheet for use in batteries, particularly for use in delaying or preventing thermal runaway in batteries. This application further relates to a multilayer thermal insulation sheet, a battery component, and a method for manufacturing a battery including a multilayer thermal insulation sheet.

[0003] Demand for electrochemical energy storage devices such as lithium-ion batteries is constantly increasing due to the growth of applications such as electric vehicles and power grid energy storage systems, as well as other multi-cell battery applications such as electric motorcycles, uninterruptible battery systems, and lead-acid battery replacements. As their use increases, methods for thermal management are desired. In large-scale applications such as power grid storage and electric vehicles, numerous electrochemical cells are often used connected in series and parallel arrays, which can lead to thermal runaway. When a cell enters thermal runaway mode, the heat generated by the cell can trigger thermal runaway propagation reactions in adjacent cells, potentially causing a cascade effect that can ignite the entire battery.

[0004] Attempts to reduce battery thermal runaway have been explored, but many have drawbacks. For example, modifying the electrolyte by adding flame-retardant additives or using an inherently non-flammable electrolyte has been considered, but these methods can negatively impact the electrochemical performance of lithium-ion cells. Other methods for thermal management or preventing cascading thermal runaway include increasing the amount of insulation between cells or between cell groups to reduce heat transfer during thermal events. However, these methods may limit the upper limit of the achievable energy density. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] With the increasing demand for batteries with improved thermal management or reduced risk of thermal runaway, there is a corresponding need for methods and components for use in batteries that prevent or delay the spread of heat, energy, or both to surrounding cells. [Means for solving the problem]

[0006] In one embodiment, the thermal insulation multilayer sheet for preventing thermal runaway comprises a non-porous elastomer barrier layer having a first surface and a second opposite surface; a flexible foam layer disposed on the first surface of the barrier layer; and a flame retardant component, wherein the flame retardant component is distributed within the flexible foam layer, in contact with the surface of the flexible foam layer, or both.

[0007] Electrochemical cells, disconnected arrays, and batteries containing the above-mentioned multilayer thermal insulation sheets are also described.

[0008] The above and other features are illustrated by the following figures, detailed description, examples and claims.

[0009] The following is a brief description of the drawings, which are provided for illustrative purposes only and not to limit the exemplary embodiments disclosed herein. [Brief explanation of the drawing]

[0010] [Figure 1A] It is a schematic diagram showing a pouch cell comprising a heat-insulating multilayer sheet adhered to the outside of the pouch cell. [Figure 1B] It is a schematic diagram of another embodiment of an electrochemical cell and a heat-insulating multilayer sheet. [Figure 2] It is a diagram showing an embodiment of a heat-insulating multilayer sheet positioned between two cells. [Figure 3] It is a diagram showing an embodiment of a heat-insulating multilayer sheet positioned between two cells. [Figure 4] It is a diagram showing an embodiment of a heat-insulating multilayer sheet positioned between cell arrays. [Figure 5] It is a diagram showing an embodiment of a battery including a heat-insulating multilayer sheet. [Figure 6] It is a schematic cross-sectional view showing an embodiment of a flame retardant component distributed in a flexible foam layer. [Figure 7] It is a schematic diagram of equipment for a hot plate test. [Figure 8] It is a graph of temperature (°C) versus time (minutes (min)) showing the results of the simulated thermal runaway test of Examples 1 to 3. [Mode for Carrying Out the Invention]

[0011] Preventing thermal runaway in batteries, especially those containing numerous electrochemical cells, is a challenge because adjacent cells can absorb enough energy from the event to cause them to exceed their designed operating temperature, thus triggering thermal runaway in those adjacent cells as well. This propagation that initiates a thermal runaway event can trigger a chain reaction in which cells enter a cascading series of thermal runaways, potentially causing one cell to ignite an adjacent cell. Insulated multilayer sheets can be used to prevent such cascading thermal runaway events. However, achieving effective thermal runaway resistance in very thin multilayer sheets, such as those with a total thickness of 30 mm or less, or 20 mm or less, or 15 mm or less, or 10 mm or less, or 8 mm or less, or 6 mm or less, has been particularly difficult. Thin multilayer sheets are increasingly desired to reduce article size and mass and to save material.

[0012] A multilayer thermal insulation sheet for preventing battery thermal runaway comprises a non-porous elastomer barrier layer having a first surface and a second opposite surface; a flexible foam layer disposed on the first surface of the barrier layer; and a flame retardant component, where the flame retardant component is distributed within the flexible foam layer, in contact with the surface of the flexible foam layer, or both. Unexpectedly, the use of a solid non-porous elastomer barrier layer with low water vapor permeability was found to be useful in producing a multilayer thermal insulation sheet, especially when it is very thin, i.e., 30 mm or less, or 20 mm or less, or 15 mm or less, or 10 mm or less, or 8 mm or less, or 6 mm or less. The multilayer thermal insulation sheet can have additional advantageous properties, such as good puncture resistance. The multilayer thermal insulation sheet can be subjected to numerous heating and cooling cycles and still provide good thermal insulation. The multilayer thermal insulation sheet can further provide pressure control to electrochemical cells and batteries. The thermal barrier obtained by the multilayer thermal insulation sheet can be used in various parts of a battery to prevent thermal runaway. The multi-layer heat-insulating sheet can further improve the flame resistance of the battery.

[0013] The multilayer insulation sheets have a thermal conductivity of 0.01–0.09 watts / meter Kelvin (W / m*K) at 23°C; thicknesses of 0.2–30 mm, or 0.2–20 mm, or 0.2–15 mm, or 0.2–10 mm, or 0.5–10 mm, or 0.5–8 mm, or 1–6 mm; or weights of 6–30 pounds / cubic foot (lb / ft). 3 )(96~481 kilograms / cubic meter (kg / m 3 )), 10-25 lb / ft 3 (160~400kg / m 3 ), or 15-20 lb / ft 3 (240~320kg / m 3 ) may have a density; or a combination thereof.

[0014] As shown in Figure 1, the heat insulating multilayer sheet 100 can be directly installed or bonded to the outer surface of a pre-formed battery cell, for example, the outer surface of a pouch cell 200. As shown, the non-porous elastomer barrier layer 10 is placed on the pouch cell 200, the flexible foam layer 22 is placed on the non-porous elastomer barrier layer 10, and the flame retardant component is a flame retardant layer 24 in contact with the surface of the flexible foam layer 22. Preferably, the elastomer barrier layer 10 has sufficient thickness to give a smooth outer surface, rather than simply being a coating bonded to the surface of the foam along the contour of the foam.

[0015] In the embodiment shown in Figure 1, the flame retardant layer 24 is in contact with the outer surface of the flexible foam layer 22. Alternatively, or on top of that, the flame retardant layer can be in contact with the inner surface of the pores within the flexible foam layer. For example, the flame retardant layer 24 can be coated onto the surface of the flexible foam layer 22. Such a coating can result in pores that are filled (i.e., completely impregnated) or partially coated with the flame retardant layer. Preferably, the inner surface of the pores is coated with an amount of flame retardant component effective in maintaining the empty pore volume to provide pressure control. In this embodiment, a portion of the pores can be filled with the flame retardant layer. In another embodiment, the flame retardant layer is in contact with the inner surface of only a portion of the pores, for example, a portion of the pores adjacent to the flame retardant layer 24. In the embodiments described above, the flame retardant layer may be continuous or discontinuous. Preferably, the flame retardant layer is continuous and present on at least the outer surface of the flexible foam layer 22.

[0016] The thermal insulation multilayer sheet 100 can be bonded to the pouch cell 200 by an adhesive layer. Furthermore, as shown in Figure 1A, the adhesive layer 30 is placed between the pouch cell and the non-porous elastomer barrier layer 10. In some embodiments, no adhesive is present, and the flexible foam layer can be placed directly on the cell, e.g., the pouch cell 200. Depending on the case, one or more adhesive layers may be placed between each individual layer. A number of adhesive layers may be present. Each of these layers is described in further detail below.

[0017] While not constrained by theory, superior results are thought to be obtained through different mechanisms working in coordination. Firstly, the flexible foam and flame retardant layers each provide barriers to heat conduction. Heat is further absorbed by the heat capacity of the flame retardant layer and the heat generated by water vapor production from the flame retardant layer. However, water vapor production leads to increased thermal convection through the flexible foam layer. The non-porous elastomer barrier layer blocks water vapor and hot gases, thereby providing improved heat resistance to the insulating multilayer sheet. In particular, water vapor generated on the heated surface of the insulating multilayer sheet is trapped by the non-porous elastomer barrier layer.

[0018] In some embodiments, multiple non-porous elastomer barrier layers, flexible foam layers, or flame retardant layers may be present. For example, Figure 1B shows a first flame retardant layer 24a directly disposed on a first flexible foam layer 22a disposed on a non-porous elastomer barrier layer 10. Furthermore, a second flame retardant layer 24b is directly disposed on a second flexible foam layer 22b disposed on the non-porous elastomer barrier layer 10 opposite to the first flexible foam layer 22a and the first flame retardant layer 24a. The thermal insulation multilayer sheet 102 is placed in the cell 202. Each flexible foam layer and each flame retardant layer may be the same or different. Again, one or more adhesive layers may be present between each layer or between a layer and an electrochemical cell. As in other embodiments, one or more adhesive layers may be present between any two layers or between a layer and an electrochemical cell.

[0019] Figure 2 illustrates a non-limiting example of positioning a thermal insulation multilayer sheet in a multi-cell array 1000. Figure 3 illustrates a non-limiting example of positioning a thermal insulation multilayer sheet in a multi-cell array 2000, and Figure 4 illustrates a non-limiting example of positioning a thermal insulation multilayer sheet in a multi-cell array 3000. Figures 2 and 3 illustrate that the thermal insulation multilayer sheet 100 can be positioned between the first cell 300 and the second cell 400. Figure 2 illustrates that the thermal insulation multilayer sheet 100 can be approximately the same size as the height and width of cells 300 and 400. Figure 3 illustrates that the thermal insulation multilayer sheet 100 can be smaller than each of the cells 300 and 400.

[0020] Figure 4 illustrates that the multi-cell array 3000 can contain more than two cells (e.g., 300 and 400), and that the insulating multilayer sheet 100 is located between each of the cells 300 and 400. The cells may be lithium-ion batteries, particularly pouch cells.

[0021] In one embodiment, 2 to 10 fire-resistant thermal insulation multilayer sheets can be placed in / within the cell during the manufacturing of the cell. For example, 2 to 10 thermal insulation multilayer sheets can be placed inside the battery, for example facing the electrodes, or outside the battery, facing the outside of the battery. For example, 2 to 10 fire-resistant thermal insulation multilayer sheets can be placed in the pouch cell (with the adhesive facing outwards), or bonded to the pouch cell, or both. In one embodiment, as shown in Figure 5, the thermal insulation multilayer sheet 100 can provide pressure or heat control in the battery 4000. For example, the battery 4000 may include a plurality of disconnected arrays 500 inside the housing or cell carrier 600. As used herein, the term “disconnected array” refers to a group of cells that are not connected to the terminals of the battery. The thermal insulation multilayer sheet 100 can be placed between the individual cells of the disconnected array. The thermal insulation multilayer sheet 100 can be installed and bonded to, or combined with, the unconnected array 500 of the battery 4000, a portion thereof, or a selected cell side of the unconnected array, on the top, in the middle, below, adjacent to, or in combination with them. The thermal insulation multilayer sheet 100 can be installed and bonded to, or combined with, the battery 4000, each cell or a portion of the unconnected array, or a selected set of cells or the unconnected array. Placement or bonding to one or more sides, including the front or back, is also possible. Again, the thermal insulation multilayer sheet 100 can be installed and bonded to, or combined with, a portion or all of, one or more sides.

[0022] In an aspect, the battery includes a battery case that houses one or more cells or disconnected arrays. The heat-insulating multilayer sheet can be installed between individual cells or disconnected arrays of the battery. The heat-insulating multilayer sheet can be installed adjacent to the top, middle, bottom of the sides of the battery cells or disconnected arrays, a portion thereof, or a selected set of battery cells or the sides of the disconnected arrays, or a combination thereof. The heat-insulating multilayer sheet can be installed or adhered to a plurality of pouch cells, pressure management pads, cooling plates, or other internal battery components, for example, in a state where no adhesive is exposed. The assembly pressure of the battery can hold the stacked components in place.

[0023] The heat-insulating multilayer sheet can be used in batteries comprising disconnected arrays, that is, a plurality of electrochemical cells. The cells include prismatic cells, pouch cells, cylindrical cells and the like.

[0024] The individual layers and components of the heat-insulating multilayer sheet 100 are described next.

[0025] Non-porous elastomer barrier layer The non-porous elastomer barrier layer is configured to delay or prevent thermal runaway, particularly in very thin multilayer structures. The non-porous elastomer barrier layer, measured at 25°C and 1 atm respectively, has a water permeability coefficient of less than 20 g-mm / m 2 ·day or less than 10 g-mm / m 2 ·day, or less than 5 g-mm / m 2 ·day; or an elastomer having a tensile stress at 100% elongation of 0.5 to 15 megapascals measured at 21°C in accordance with ASTM 412; or a combination thereof. The non-porous elastomer barrier layer can have a thickness of 0.25 to 1 mm or 0.4 to 0.8 mm.

[0026] A non-porous elastomer barrier layer may include an elastomer material that is hydrophobic to prevent water or water vapor permeation. For example, the elastomer barrier layer may include a thermoplastic elastomer (TPE), provided that it has preferred hydrophobicity (lack of water or water vapor permeation). Classes of TPE include styrene block copolymers (TPS or TPE-s), (TPO or TPE-o), thermoplastic vulcanized products (TPV or TPE-v), thermoplastic polyurethanes, thermoplastic copolyesters (TPC or TPE-E), thermoplastic polyamides (TPA or TPE-A), and others.

[0027] Specific examples of elastomer materials that can have desirable hydrophobicity (lack of water or water vapor permeability) include acrylic rubber, butyl rubber, halogenated butyl rubber, copolyester, epichlorohydrin rubber, ethylene-diene rubber (EPR) such as ethylene-acrylic rubber, ethylene-butylacrylic rubber, and ethylene-propylene rubber, ethylene-propylene-diene monomer rubber (EPDM), ethylene-vinyl acetate, fluororubber, perfluoroelastomer, polyamide, polybutadiene, polychloroprene, polyolefin rubber, polyisoprene, polysulfide rubber, natural rubber, nitrile rubber, low-density polyethylene, polypropylene, thermoplastic polyurethane elastomer (TPU), silicone rubber, fluorinated silicone rubber, styrene-butadiene, styrene-isoprene, vinyl rubber, or combinations thereof. In an embodiment, the barrier layer includes ethylene-propylene-diene monomer rubber, polychloroprene, or combinations thereof.

[0028] Flexible foam layer The flexible foam layer may be a low-density foam that provides pressure control and allows cell expansion. The flexible foam layer may also have good compression set resistance and minimal stress relaxation, preferably less than 10% compression and more than 50% force retention. The flexible foam layer may be thermally conductive. For example, the flexible foam layer may have a low thermal conductivity (Tc), e.g., 0.01 to 0.5 W / m*K at 23°C, or 0.01 to 0.09 W / m*K at 23°C. The flexible foam layer may be a polymer foam or a flexible aerogel.

[0029] In each embodiment, each flexible foam layer is independently determined according to ASTM D3574-17 at 25% deflection to have a compressive deflection of 0.2 to 125 pounds per square inch (psi) (1 to 862 kilopascals (kPa)), or 0.25 to 20 psi (1.7 to 138 kPa), or 0.5 to 10 psi (3.4 to 68.90 kPa); a compression set of 0 to 15%, or 0 to 10%, or 0 to 5%, determined at 70°C according to ASTM D 3574-95 Test D; or 5 to 65 lb / ft 3 (80~1,041 kg / m 3 ), or 6-20 lb / ft 3 (96~320kg / m 3 ), or 8-15 lb / ft 3 (128~240kg / m 3 It has a density of ).

[0030] Each flexible foam layer can independently have a thickness of 0.1 to 5 mm, 1 to 3 mm, or 1.5 to 2.5 mm. Each flexible foam layer may independently be silicone, polyurethane, aerogel, ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), ethylene butyl acrylate (EBA), or a combination thereof. Exemplary flexible foam layers may include polymer foams such as polyurethane foam or silicone foam, or elastomer polymers such as vinyl acetate (EVA), thermoplastic elastomer (TPE), EPM (ethylene-propylene rubber), or EPDM (ethylene-propylene-diene monomer) rubber. For example, a flexible foam layer may include, for example, PORON® polyurethane foam or BISCO® silicone foam, which have reliable compression set resistance (c-set) and stress relaxation performance over a wide temperature range.

[0031] As used herein, “foam” refers to a material having a permanent, for example, thermosetting cellular structure. Foams are flexible, as opposed to rigid. The example foam used in a flexible foam layer is 65 lb / ft 3 (1,041 kg / m 3 ) Less than 55 lb / ft 3 (881kg / m 3 ) equal to or less than, more preferably 25 lb / ft 3 (400kg / m 3 The foam has a density equal to or less than 5-99%, preferably equal to or greater than 30%, or a combination thereof, relative to the total volume of the polymer foam. In this embodiment, the foam has a density of 5-30 lb / ft 3 (80~481kg / m 3 It has a density of ).

[0032] The polymer used as the foam may be a variety of thermoplastic resins, a blend of thermoplastic resins, or one or more thermosetting resins. Examples of thermoplastic resins that can be used include polyacetal, polyacrylic, styrene-acrylonitrile, polyolefin, acrylonitrile-butadiene-styrene, polycarbonate, polystyrene, esters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6, nylon 6,6, nylon 6,10, nylon 6,12, nylon 11 or nylon 12, polyamide-imide, polyaryllate, polyurethane, ethylene propylene rubber (EPR), polyarylsulfone, polyethersulfone, polyphenylene sulfide, polyvinyl chloride, polysulfone, polyetherimide, polytetrafluoroethylene, fluorinated ethylene propylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyether ketone, polyetherether ketone, polyetherketone ketone, etc.

[0033] Examples of thermoplastic polymer blends that can be used in polymer foams include acrylonitrile-butadiene-styrene / nylon, polycarbonate / acrylonitrile-butadiene-styrene, acrylonitrile-butadiene-styrene / polyvinyl chloride, polyphenylene ether / polystyrene, polyphenylene ether / nylon, polysulfone / acrylonitrile-butadiene-styrene, polycarbonate / thermoplastic urethane, polycarbonate / polyethylene terephthalate, polycarbonate / polybutylene terephthalate, thermoplastic elastomer alloy, polyethylene terephthalate / polybutylene terephthalate, styrene-maleic anhydride / acrylonitrile-butadiene-styrene, polyetheretherketone / polyethersulfone, styrene-butadiene rubber, polyethylene / nylon, polyethylene / polyacetal, ethylene propylene rubber (EPR), etc., or combinations thereof.

[0034] Examples of polymeric thermosetting resins that can be used in polymer foams include polyurethane, epoxy, phenolic resins, polyester, polyamide, silicone, etc., or combinations thereof. Blends of thermosetting resins, as well as blends of thermosetting resins with thermoplastic resins, can also be used.

[0035] Silicone foams containing polysiloxane polymers can also be used. In one embodiment, the silicone foam is produced as a result of a reaction between water and hydride groups in the polysiloxane polymer precursor composition, followed by the liberation of hydrogen gas. This reaction can be catalyzed with a noble metal, preferably platinum. In one embodiment, the polysiloxane polymer has a viscosity of 100 to 1,000,000 poise at 25°C and has chain substituents such as hydride, methyl, ethyl, propyl, vinyl, phenyl, and trifluoropropyl. The terminal groups of the polysiloxane polymer may be hydride, hydroxyl, vinyl, vinyldiorganosiloxy, alkoxy, acyloxy, allyl, oxime, aminooxy, isopropeneoxy, epoxy, mercapto groups, or other reactive terminal groups. The silicone foam can also be produced by using several polysiloxane polymers having different molecular weights (e.g., bimodal or trimodal molecular weight distributions), as long as the combined viscosity is within a predetermined range. Furthermore, to produce the desired foam, it is also possible to have several polysiloxane-based polymers containing different functional or reactive groups. In one embodiment, the polysiloxane polymer contains 0.2 moles of hydride (Si--H) groups per mole of water.

[0036] Depending on the chemical reaction of the polysiloxane polymer used, catalysts, such as platinum or platinum-containing catalysts, can be used to catalyze the foaming and curing reactions. The catalyst can be deposited on an inert support such as silica gel, alumina, or carbon black. In some embodiments, the unsupported catalyst may be chloroplatinic acid, its hexahydrate form, its alkali metal salt, or a complex thereof with an organic derivative.

[0037] Certain aerogels can be used as flexible foam layers. Aerogels are open-cell solid matrices containing a network of interconnected nanostructures having a porosity of more than 50 volume percent (vol%), more preferably more than 90 vol%. Aerogels can be derived from gels by replacing the liquid component in the gel with gas, or by drying a humid gel, for example, by supercritical drying. Exemplary aerogels include polymer aerogels, e.g., poly(vinyl alcohol), polyurea, polyurethane, polyimide, resorcinol formaldehyde polymer, polyisocyanate, epoxy and polyacrylamide aerogels; polysaccharide aerogels, including chitin and chitosan aerogels; and inorganic aerogels, e.g., carbon (e.g., graphene) aerogels, ceramic aerogels (e.g., boron nitride aerogels), and metal oxide and metalloid oxide aerogels (e.g., aluminum oxide, vanadium oxide and silica aerogels). Combinations of the aforementioned materials, e.g., silica aerogel crosslinked with organic diisocyanates, can be used.

[0038] Aerogels can have compressive deflections of 0.2 to 150 psi (1.4 to 1,034 kPa), preferably 2 to 25 psi (13.8 to 172 kPa), determined by 25% deflection according to ASTM D3574-17. The density of the aerogel is 1 to 20 lb / ft. 3 (16~320kg / m 3 ), preferably 2-15 lb / ft 3 (32~240kg / m 3 ), more comfortable 2-10 lb / ft 3 (32~160kg / m 3 ) may also be used. The thickness of the aerogel may be 0.5 to 10 mm, preferably 1 to 6 mm, more preferably 1 to 3 mm.

[0039] In this embodiment, the aerogel may be a silica aerogel containing reinforcing fibers. The reinforcing fibers may include polyester, oxidized polyacrylonitrile, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, glass fiber, high-density polyolefin, ceramic, acrylic resin, fluoropolymer, polyurethane, polyamide, polyimide, or a combination thereof.

[0040] Optional additives may be present in the elastomer polymer, polymer foam, or aerogel. For example, the additives may include reinforcing materials such as reinforcing particulate materials or reinforcing fibrous materials. Exemplary reinforcing particulate materials include lignin, carbon black, talc, mica, silica, quartz, metal oxides, glass microspheres, polyhedral oligomer silsesquioxanes, substituted polyhedral oligomer silsesquioxanes, or combinations thereof. Exemplary reinforcing fibrous materials include fibrous materials in which the fibers of the reinforcing fibrous material are polyester, oxidized polyacrylonitrile, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, glass fiber, high-density polyolefin, ceramic, acrylic resin, fluoropolymer, polyurethane, polyamide, polyimide, or combinations thereof, where the fibers may be in any form such as a woven mat or a nonwoven mat. Combinations of reinforcing particulate materials and reinforcing fibrous materials can be used. Additives may include fillers (e.g., calcium carbonate or clay), dyes, pigments (e.g., titanium dioxide or iron oxide), antioxidants, ozone degradation inhibitors, UV stabilizers, thermally conductive particulate materials (e.g., boron nitride or alumina), or conductive fillers (e.g., particulate conductive polymers). Combinations of additives may be used.

[0041] The exemplified glass fibers may be woven fabrics or nonwoven fabrics such as felt. The glass fibers may include, for example, E glass fibers, S glass fibers, D glass fibers, L glass fibers, quartz fibers, or combinations thereof. The glass fibers may have thicknesses of, for example, 0.005-10 mm, 0.05-5 mm, 0.25-3 mm, 0.005-0.05 mm, 0.05-0.5 mm, 0.5-3 mm, 0.25-10 mm, 0.5-5 mm, or 1-3 mm. The glass fibers may optionally be impregnated or coated with thermosetting or thermoplastic polymers. Exemplary thermosetting polymers include epoxy, polyester, and vinyl esters.

[0042] The exemplary microspheres include cenospheres, glass microspheres, such as borosilicate microspheres, or combinations thereof. The microspheres are hollow spheres having an average diameter of less than 300 micrometers (μm), for example, 15-200 μm or 20-100 μm. The density of the hollow microspheres may be 0.1 grams / cubic centimeter (g / cc) or more, for example, in the range of 0.2-0.6 g / cc or 0.3-0.5 g / cc.

[0043] Hollow microspheres are available from several commercial sources, such as Trelleborg Offshore (Boston) (formerly Emerson and Cuming, Inc.), WR Grace and Company (Canton, MA), and 3M Company (St. Paul, MN). Such hollow microspheres are referred to as microballoons, bubble glass, microbubbles, etc., and are sold in various grades, which can vary according to, for example, density, size, coating, surface treatment, or combinations thereof.

[0044] For example, the microspheres may have an outer surface that has been chemically modified by treatment with a coupling agent that can react with hydroxyl groups present on the glass surface. In this embodiment, the coupling agent is a silane or epoxy, for example, an organosilane having a group at one end that can react with hydroxyl groups present on the outer surface of the glass microspheres, and an organic group at the other end that assists the dispersibility of the microspheres in a low-polarity polymer matrix. The bifunctional silane coupling may have a combination of groups selected from vinyl, hydroxyl, and amino groups, for example, 3-amino-propyltriethoxysilane. The silane coating can also minimize water absorption.

[0045] Borosilicate microspheres can be produced from alkali borosilicate glass. An example oxide composition of alkali borosilicate may contain 76.6 wt% SiO2, 21.3 wt% Na2O, 1.9 wt% B2O3, and 0.2 wt% other components. An example soda-lime borosilicate may contain 80.7 wt% SiO2, 6.9 wt% Na2O, 10.3 wt% CaO, 2.1 wt% B2O3, and 1.9 wt% impurities. Therefore, the composition (mostly SiO2, but containing at least 1 percent B2O3) can vary to some extent depending on the starting material.

[0046] The size of the microspheres and their particle size distribution can vary. In the exemplary embodiment, the borosilicate microspheres exhibit an average particle size of 20-100 μm, for example, 20-75 μm, 25-70 μm, 30-65 μm, 35-60 μm, or 40-55 μm. The particle size distribution may be bimodal or trimodal, etc.

[0047] The reinforcing microparticle material may include polyhedral oligomeric silsesquioxane (commonly referred to as "POSS," and also referred to herein as "silsesquioxane"), substituted polyhedral oligomeric silsesquioxane, or combinations thereof. The inclusion of silsesquioxane can provide the additional benefit of improving the durability of the flexible foam layer in an oxidizing environment. Silsesquioxane is a nano-sized inorganic material containing a silica core that may have reactive functional groups on its surface. Silsesquioxane may have a cubic or cubic structure containing silicon atoms at its vertices and interconnected oxygen atoms. Each silicon atom may be covalently bonded to a pendant R group. Formula (I)(R8Si8O 12 The silsesquioxane contains a cage of silicon and oxygen atoms around a core containing eight pendant R groups.

[0048] [ka]

[0049] Silsesquioxane may be substituted or unsubstituted, and each R group may independently be hydrogen, a hydroxyl group, an alkyl group, an aryl group, or an alkenyl group, where the R group may contain 1 to 12 carbon atoms and one or more heteroatoms (e.g., at least one of oxygen, nitrogen, phosphorus, silicon, or halogen). Each R group may independently contain one or more reactive groups such as at least one of an alcohol, epoxy group, ester, amine, ketone, ether, halide, or combination thereof. Each R group may independently contain at least one of a silanol, alkoxide, or chloride. An example of a silsesquioxane is octa(dimethylsiloxy)silsesquioxane.

[0050] A flexible foam layer, such as a silicone flexible foam layer, can be immersed in a solvent, such as water, for a period of time such as 24 hours, allowing the silicone flexible foam layer to absorb water. The large heat capacity of liquid water can significantly delay heat transfer from one surface of the flexible foam layer to the other surface.

[0051] Flame retardant components The flame retardant component may further include expandable materials such as those described below, such as flame-retardant inorganic materials like boehmite, aluminum hydroxide, and magnesium hydroxide, or combinations thereof. As described above, the flame retardant component can exist as a flame retardant layer in contact with the surface of the flexible foam. In particular, when in contact with the outer surface of the flexible foam layer, each flame retardant layer may have a thickness of 0.1 to 2 mm, 0.5 to 1.5 mm, or 0.8 to 1.1 mm. The flame retardant layer in contact with the inner surface of the pores may be thinner, for example, 0.01 to 1 mm, 0.01 to 0.8 mm, or 0.01 to 0.8 mm.

[0052] Alternatively, or in addition to the above, the flame retardant component may be a flame retardant material distributed within the matrix of the flexible foam layer itself. Figure 6 illustrates an example of a flame retardant component distributed within the matrix of the flexible foam layer 12. The flexible foam layer 12 has a first outer surface 14 and an opposite second outer surface 16. Although shown as flat, the contours of one, both, or all of the outer surfaces can be tightly fitted to the surface of the electrochemical cell.

[0053] The flexible foam layer 12 further includes a plurality of pores 18. The pores are defined in the polymer foam matrix by the inner surface 20 of the pores. The pores may be interconnected or discrete. A combination of interconnected and discrete pores may exist. The pores as a whole may be contained within the sheet, or at least some of the pores may be open, allowing contact with the surrounding environment. In one embodiment, at least some of the pores are interconnected, and at least some of the pores are open, allowing the passage of air, water, water vapor, etc. from a first outer surface 14 to an opposite second outer surface 16, which is referred to herein as a "continuous-cell foam". In another embodiment, the pores are not interconnected and do not allow the passage of air, water, water vapor, etc. from one outer surface to the other.

[0054] Referring further to Figure 6, the flame retardant components may include two or more different flame retardant components 23, 25 distributed within the matrix of the flexible foam layer 12. The flame retardant components can be distributed basically uniformly or in a gradual manner, increasing, for example, from the first outer surface 14 to the second outer surface 16. As shown in Figure 6, the flame retardant components can be distributed within the flexible foam layer matrix in the form of fine particles. Flame retardant components in the form of fine particles can be easily incorporated into the flexible foam layer during their fabrication.

[0055] Alternatively, or in addition thereto, particulate flame retardant components can be present within the pores of the flexible foam layer. Some of the pores in the flexible foam layer may contain particulate flame retardant components, or essentially all or all of the pores may contain particulate flame retardant components. Each pore containing particulate flame retardant components can independently be partially filled, essentially completely filled, or completely filled. In embodiments where the particulate flame retardant particles are large relative to the diameter of the pore, or where the pore is essentially or completely filled with a plurality of smaller particles, the movement of the flame retardant particles within the pore can be restricted. In this embodiment, particulate flame retardant components can be located in the pores during the fabrication of the layer (for example, by including particulate flame retardant components in the composition used to form the flexible foam layer), or particulate flame retardant components can be impregnated into the pores after the fabrication of the flexible foam layer using a suitable liquid carrier, vacuum, or other known method.

[0056] Different combinations of flame retardant components, including different types, forms, or arrangements, can be used. For example, the flame retardant layer can be used in combination with flame retardant particulate material distributed within a flexible foam matrix; or the flame retardant layer can be used in combination with particulate flame retardant components disposed within the pores of a flexible polymer layer. In one embodiment, the expandable flame retardant layer is used in combination with flame retardant particulate material distributed within a flexible foam matrix. In a preferred embodiment, the expandable flame retardant layer is used alone for ease of manufacture and to maintain the desired thinness and flexibility of the flexible polymer foam.

[0057] Expandable materials can include an acid source, a blowing agent, and a carbon source. Each component can exist in separate layers or as a mixture, preferably a dense mixture. For example, an expandable material can include a polyphosphoric acid source, a blowing agent, and a pentaerythritol carbon source. While not bound by theory, it is thought that expandable materials can reduce flame propagation by using two energy absorption mechanisms, including char formation and subsequent swelling of the char. For example, when the temperature reaches a value of, for example, 200-280°C, an acidic species (e.g., a polyphosphoric acid) can react with a carbon source (e.g., pentaerythritol) to form char. When the temperature rises to, for example, 280-350°C, the blowing agent can then decompose to give gaseous products that swell the char.

[0058] The acid source may include, for example, organic or inorganic phosphorus compounds, organic or inorganic sulfates (e.g., ammonium sulfate), or combinations thereof. Organic or inorganic phosphorus compounds may include organophosphates or organophosphonates (e.g., tris(2,3-dibromopropyl)phosphate, tris(2-chloroethyl)phosphate, tris(2,3-dichloropropyl)phosphate, tris(l-chloro-3-bromoisopropyl)phosphate, bis(1-chloro-3-bromoisopropyl)-1-chloro-3-bromoisopropylphosphonate, polyaminotriazine phosphate, melamine phosphate, triphenyl phosphate, or guanylurea phosphate); organic phosphite esters (e.g., trimethyl phosphite, or triphenyl phosphite); phosphazenes (e.g., hexaphenoxycyclotriphosphazene); phosphorus-containing inorganic compounds (e.g., phosphoric acid, phosphite, phosphite, urea phosphate, ammonium phosphate (e.g., ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, or ammonium polyphosphate)); or combinations thereof.

[0059] The foaming agent may include reagents that decompose at temperatures equal to or above 120°C, for example, 120-200°C or 130-200°C (into smaller compounds such as ammonia or carbon dioxide). The foaming agent may include dicyandiamide, azodicarbonamide, melamine, guanidine, glycine, urea (e.g., urea-formaldehyde resin or methylolated guanylurea phosphate), halogenated organic materials (e.g., chlorinated paraffin), or combinations thereof.

[0060] Expandable materials may contain a carbon source. A flexible foam layer can function as a carbon source. The carbon source may include dextrin (phenol-formaldehyde resin), pentaerythritol (e.g., their dimers or trimers), clay, polymers (e.g., polyamide 6, amino-poly(imidazoline-amide) or polyurethane), or combinations thereof. Amino-poly(imidazoline-amide) may contain repeating amide linking groups and imidazoline groups.

[0061] The expandable material may optionally further contain a binder. The binder may include epoxy, polysulfide, polysiloxane, polysilarylene, or a combination thereof. The binder may be present in the expandable material in an amount equal to or less than 50 wt%, or 5 to 50 wt%, or 35 to 45 wt%, relative to the total mass of the expandable material. The binder may be present in the expandable material in an amount of 5 to 95 wt%, or 40 to 60 wt%, relative to the total mass of the expandable material.

[0062] Expandable materials may optionally contain synergistic compounds to further improve their flame retardancy. Synergistic compounds may include boron compounds (e.g., zinc borate, boron phosphate, or boron oxide), silicon compounds, aluminosilicates, metal oxides (e.g., magnesium oxide, iron oxide, or aluminum oxide hydrate (boehmite)), metal salts (e.g., alkali metal salts or alkaline earth metal salts or alkaline earth metal carbonate salts of organic sulfonic acids), or combinations thereof. Preferred synergistic combinations include phosphorus-containing compounds comprising at least one of the aforementioned.

[0063] The flame retardant layer may further contain char-forming agents, preferably lignin, boehmite, clay nanocomposites, expandable graphite, pentaerythritol, cellulose, nanosilica, ammonium polyphosphate, lignosulfonate, melamine, cyanurate, zinc borate, hantite, dolomitic or a combination thereof. Although not bound by theory, it is thought that, like expandable materials, char-forming agents can reduce flame spread by using two energy absorption mechanisms, including forming char and then swelling the char.

[0064] The flame retardant component may include organic flame retardants such as melamine, triazine, phosphoamidate, aryl or alkyl phosphate, aryl or alkyl phosphonate, aryl or alkyl phosphinate, aryl or alkylphosphine or their corresponding oxides, phosphazenes, etc., or combinations thereof. In some embodiments, flame retardant compounds containing halogens, such as bromine or chlorine, are absent. The flame retardant component may include inorganic flame retardants such as aluminum hydroxide (including aluminum trihydrate and various hydrates of aluminum oxide when used herein), boehmite, borax (sodium tetraborate pentahydrate), hydrated sodium silicate, magnesium hydroxide, magnesium carbonate hydroxide pentahydrate, trimagnesium phosphate octahydrate, or zinc borate, preferably at least two of aluminum trihydrate, borax, hydrated sodium silicate, magnesium hydroxide, magnesium carbonate hydroxide pentahydrate, trimagnesium phosphate octahydrate, or zinc borate. For example, the flame retardant component may include aluminum trihydrate and zinc borate; or borax and hydrated sodium silicate; or aluminum trihydrate, zinc borate and hydrated sodium silicate; or borax and zinc borate; or borax, zinc borate and aluminum trihydrate.

[0065] In one embodiment, organic and inorganic flame retardants are present in the flame retardant component, and in another embodiment, only inorganic flame retardants are present in the flame retardant component. Inorganic flame retardants are generally available in the form of particles. The particles may be irregular or regular, and may have any shape, such as nearly spherical, spherical, or plate-like. In an important feature, most, basically all, or all particles have a maximum dimension less than the thickness of the layer or pore in which they are located in order to give the layer a smooth surface. Thus, the specific diameter used depends on the position of the particles. Particles with two, three, or higher-order distribution modes can be used. For example, if the flame retardant particles are present in the matrix of a flexible foam layer and in the pores of a flexible foam layer, particles with a bimodal distribution can be present.

[0066] As described above, the flame retardant components, such as an expandable material, a char-forming agent, and a flame retardant (preferably an inorganic flame retardant), can be in the form of a layer. The flame retardant layer may further contain a polymer binder for the flame retardant components. Similar to the flexible foam layer, the polymer binder for the flame retardant layer may include, for example, silicone, polyurethane, ethylene-vinyl acetate, ethylene-methyl acrylate, ethylene-butyl acrylate, or a combination thereof. The description of such materials will not be repeated. The amount of binder relative to the amounts of expandable material, char-forming agent, and flame retardant (preferably an inorganic flame retardant) may vary depending on factors such as the desired properties of the flame retardant layer and the processability of the composition used to form the layer. For example, the binder may be present in an amount of 20 to 80 volume percent (vol.%) or 40 to 70 volume percent relative to the total volume of the composition used to form the flame retardant layer.

[0067] In one embodiment, the flame retardant component can be distributed within the matrix of the flexible foam layer. Since achieving the desired flame retardancy and foam properties using only the flexible foam layer and the non-porous elastomer layer can be more challenging, it is preferable that the flame retardant component is distributed within the matrix of the flexible foam layer, and that such a flame retardant layer exists. In this embodiment, the flame retardant component may include an expansive composition, a char-forming agent, an organic flame retardant compound, an inorganic flame retardant, or a combination thereof, for example, a combination of organic and inorganic flame retardants. Alternatively, the flame retardant component distributed within the matrix of the flexible foam layer may consist only of an organic flame retardant. In another embodiment, the flame retardant component may consist only of the inorganic flame retardants described above. For example, the flame retardant component may include aluminum trihydrate, borax, hydrated sodium silicate, magnesium hydroxide, magnesium carbonate hydroxide pentahydrate, trimagnesium phosphate octahydrate, or zinc borate, as disclosed herein, distributed within the flexible foam layer.

[0068] Flame retardant components, such as aluminum trihydrate, borax, hydrated sodium silicate, magnesium hydroxide, magnesium carbonate hydroxide pentahydrate, trimagnesium phosphate octahydrate, or zinc borate, can be incorporated into the foam-forming composition of the flexible foam layer before the foam-forming composition is foamed and cured. The flame retardant components, such as aluminum trihydrate, borax, hydrated sodium silicate, magnesium hydroxide, magnesium carbonate hydroxide pentahydrate, trimagnesium phosphate octahydrate, or zinc borate, can be distributed basically uniformly or in a gradual manner, for example, increasing in the thickness direction of the flexible foam layer in which the flame retardant components are distributed.

[0069] The amounts of the composition used to form the flexible foam layer relative to the amounts of the expandable material, char-forming agent, and flame retardant (preferably an inorganic flame retardant) may vary depending on factors such as the desired properties of the flame retardant layer and the processability of the composition used to form the layer. For example, if an inorganic flame retardant is present, the flame retardant components may be present in amounts of 10 to 90 volume percent (vol.%) or 20 to 80 volume percent, respectively, relative to the total volume of the composition used to form the flexible foam layer. If only an organic flame retardant or char-forming agent is present, the flame retardant components may be present in amounts of 0.1 to 15 wt.% or 1 to 10 wt.%, respectively, relative to the total volume of the composition used to form the flexible foam layer.

[0070] adhesive layer Various adhesives known in the industry can be used on the thermal insulation multilayer sheet. The adhesive can be selected for ease of application and stability under operating conditions. Each adhesive layer may be the same or different, and may be the same or different thicknesses. Suitable adhesives include phenolic resins, epoxy adhesives, polyester adhesives, polyvinyl fluoride adhesives, acrylic or methacrylic adhesives, or silicone adhesives, preferably acrylic or silicone adhesives. In some embodiments, the adhesive is a silicone adhesive. Solvent-cast, hot-melt two-component adhesives can be used. Each adhesive layer can independently have a thickness of 0.00025 to 0.010 inches (0.006 to 0.25 mm) or 0.0005 to 0.003 inches (0.01 to 0.08 mm).

[0071] Additional layer Additional layers may be present in the thermal insulation multilayer sheet to improve the fabrication, handling, performance, or other desired properties. For example, a support layer may be placed on or directly on the flexible foam layer to improve ease of handling. Such layers may be polymer layers, such as polyimide, polyetherimide, polyester (e.g., polybutylene terephthalate or polyethylene terephthalate), etc.

[0072] If the thermal insulation multilayer sheet includes an adhesive layer, the thermal insulation multilayer sheet may further include a release layer. "Release layer" means any single or composite layer including a release coating supported on one or more additional layers, which may include a release liner. The thickness of each release layer may be 5–150 μm, 10–125 μm, 20–100 μm, 40–85 μm, or 50–75 μm.

[0073] Thermal insulation multilayer sheets can be assembled by methods known in the art. The sheets can be assembled onto the surface of cells or other components of a battery (e.g., the walls of the battery case). In some embodiments, the sheets are assembled separately and then installed or bonded to cells, components, or both. Each sheet can be manufactured separately and then laminated (installed, or bonded, for example, using one or more adhesive layers) in a desired order. Alternatively, one or more individual layers can be manufactured into separate individual layers by, for example, coating, casting, or lamination using heat and pressure. In some embodiments, for example, a flexible foam layer can be cast directly onto a non-porous elastomer barrier layer. Lamination and direct coating or casting can reduce thickness and improve flame retardancy by eliminating adhesive layers.

[0074] The heat-insulating multilayer sheet can be used in a wide variety of applications, including batteries, particularly lithium-ion batteries in electric vehicles, hybrid vehicles, power grid energy storage systems, and other multi-cell battery applications such as uninterruptible battery systems and lead-acid battery replacements. As used herein, "vehicle" includes automobiles, buses, motorcycles, scooters, bicycles, trains, ships, etc. Other applications include all types of electronic devices, including mobile terminals.

[0075] As explicitly stated above, when a low mass or thickness is desired, an insulating multilayer sheet can be used. Accordingly, in this embodiment, the insulating multilayer sheet for preventing thermal runaway of the battery comprises a non-porous elastomer barrier layer having a first surface and a second opposite surface; a flexible foam layer disposed on the first surface of the barrier layer; and a flame retardant component, where the flame retardant component is distributed within the matrix of the flexible foam layer, in contact with the surface of the flexible foam, or both, and the insulating multilayer sheet has a thickness of 30 mm or less, or 20 mm or less, or 15 mm or less, or 10 mm or less, or 8 mm or less, or 6 mm or less. In this embodiment, the non-porous elastomer barrier layer may be ethylene-propylene-diene monomer rubber or polychloroprene, and the flexible foam layer may be silicone foam, polyurethane foam or aerogel.

[0076] The following examples are provided to illustrate this disclosure. The examples are illustrative and are not intended to limit the devices manufactured in accordance with the disclosures of materials, conditions or process parameters described herein. [Examples]

[0077] The materials listed in Table 1 were used in the examples.

[0078] [Table 1]

[0079] (Example 1) The surfaces of two silicone flexible foam layers were coated to a thickness of 5.8 mm with a coating containing 66 mass percent aluminum hydroxide in a silicone elastomer and cured in a convection oven at 85°C for 15 minutes. Each of the silicone flexible foam layers was bonded to the opposite surface of the polychloroprene layer with an acrylic adhesive to form a thermally insulating multilayer with the coated surface of the silicone flexible foam layer facing outwards.

[0080] (Example 2) A Pyrogel layer was bonded to the surface of a polyurethane flexible foam layer using a multipurpose adhesive.

[0081] (Example 3) A layer of flexible silicone foam was bonded to the opposite surface of a polychloroprene layer, and the layered composite was immersed in water at 70°C for 24 hours to allow the flexible silicone foam layer to absorb water, so that the high heat capacity of liquid water would be beneficial in significantly delaying heat transfer from one surface to the other.

[0082] Thermal runaway simulation Each sample from Examples 1-3 was evaluated in a test designed to simulate the high temperatures of a thermal runaway event. Figure 7 illustrates the hot plate test equipment 5000 used. The insulating multilayer sheet 102 was placed directly on a hot plate 700 set to 550°C. The pyrogel surface of Example 2 was placed on the hot plate. A 12.7 mm mica plate cell-like material 900 was placed on the upper surface of the insulating multilayer sheet 102. A thermocouple sensor 800 was inserted into a hole in the mica plate cell-like material 900 and placed on the upper surface of the insulating multilayer sheet 102. Heat from the hot plate diffused to the sample, and when it reached approximately 220°C, water vapor was generated.

[0083] Figure 8 shows the temperature rise detected by thermocouples for each sample measured over time. Compared to Examples 2 and 3, the insulating multilayer sheet of Example 1 provided better thermal protection against the opposite surface. After 10 minutes, the temperature measured for Example 1 was lower than that of Examples 2 and 3, respectively. For electric vehicle battery applications, the technical feasibility can be determined by the time it takes to reach 150°C, preferably as long as possible, for example, at least 10 minutes. Even after a long exposure of 20 minutes, the opposite surface of the insulating multilayer sheet of Example 1 was only 140°C and did not reach 150°C.

[0084] While not bound by theory, the excellent results obtained in Example 1 are thought to be due to different mechanisms working in coordination. Firstly, in all examples, the aluminum hydroxide, polychloroprene, silicone foam, polyurethane foam, and Pyrogel layers all provide barriers to heat conduction. Heat conduction is slower in Example 2 than in Example 3. In the presence of the flame retardant layer (i.e., aluminum hydroxide), heat is further absorbed due to the heat capacity of aluminum hydroxide and the heat generated from water vapor production from the aluminum hydroxide. However, water vapor production leads to increased thermal convection through the porous material (i.e., foam). The non-porous polychloroprene layer blocks water vapor and hot gases, thereby providing improved heat resistance to the multilayer sheet. In particular, the water vapor generated on the heated surface of the insulating multilayer sheet in Example 1 is trapped by the polychloroprene layer.

[0085] The following describes some non-limiting aspects of this disclosure.

[0086] Embodiment 1: A thermal insulation multilayer sheet for preventing thermal runaway, comprising: a non-porous elastomer barrier layer having a first surface and a second opposite surface; a flexible foam layer disposed on the first surface of the barrier layer; and a flame retardant component, wherein the flame retardant component is distributed within the flexible foam layer, in contact with the surface of the flexible foam layer, or both.

[0087] Embodiment 2: The thermal insulation multilayer sheet according to Embodiment 1, further comprising an additional flexible foam layer disposed on the second surface of a non-porous elastomer barrier layer.

[0088] Embodiment 3: The non-porous elastomer barrier layer measured at 25°C and 1 atm, respectively, yielded 20 g-mm / m². 2 Less than a day, or 10g-mm / m 2 Less than a day, or 5g-mm / m 2 A thermal insulation multilayer sheet according to Embodiment 1 or Embodiment 2, comprising an elastomer having a water permeability coefficient of less than 1 day; a tensile stress at 100% elongation of 0.5 to 15 megapascals as measured at 21°C according to ASTM 412; or a combination thereof.

[0089] Embodiment 4: A thermal insulation multilayer sheet according to any one of Embodiments 1 to 3, wherein the non-porous elastomer barrier layer has a thickness of 0.25 to 1 mm or 0.4 to 0.8 mm.

[0090] Embodiment 5: A heat insulating multilayer sheet according to any one of Embodiments 1 to 4, wherein the non-porous elastomer barrier layer comprises acrylic rubber, butyl rubber, halogenated butyl rubber, epichlorohydrin rubber, ethylene-acrylic rubber, ethylene-butylacrylic rubber, ethylene-diene rubber, ethylene-propylene rubber, ethylene-propylene-diene monomer rubber, ethylene-vinyl acetate, fluororubber, perfluoroelastomer, polyamide, polybutadiene, polychloroprene, polyolefin rubber, polyisoprene, polysulfide rubber, natural rubber, nitrile rubber, low-density polyethylene, polypropylene, thermoplastic polyurethane elastomer, silicone rubber, fluorinated silicone rubber, styrene-butadiene, styrene-isoprene, vinyl rubber, or a combination thereof.

[0091] Embodiment 6: A heat insulating multilayer sheet according to any one of Embodiments 1 to 5, wherein the non-porous elastomer barrier layer comprises ethylene-propylene-diene monomer rubber, polychloroprene, or a combination thereof.

[0092] Apparatus 7: Each flexible foam layer is independently determined at 25% deflection according to ASTM D3574-17 to compressive deflection of 0.2 to 125 pounds per square inch (1 to 862 kilopascals), or 0.25 to 20 pounds per square inch (1.7 to 138 kilopascals), or 0.5 to 10 pounds per square inch (3.4 to 68.90.5 kilopascals); ASTM D A thermal insulation multilayer sheet according to any one of embodiments 1 to 6, having a compression set of 0 to 15%, or 0 to 10%, or 0 to 5%, as determined at 70°C according to Test D 3574-95; a density of 5 to 65 pounds / cubic foot (80 to 1,041 kilograms / cubic meter), or 6 to 20 pounds / cubic foot (96 to 320 kilograms / cubic meter), or 8 to 15 pounds / cubic foot (128 to 240 kilograms / cubic meter); or a combination thereof.

[0093] Embodiment 8: A thermal insulation multilayer sheet according to any one of Embodiments 1 to 7, wherein each flexible foam layer independently has a thickness of 0.1 to 5 mm, 1 to 3 mm, or 1.5 to 2.5 mm.

[0094] Embodiment 9: A thermal insulation multilayer sheet according to any one of Embodiments 1 to 8, wherein each flexible foam layer independently comprises silicone, polyurethane, aerogel, ethylene-vinyl acetate, ethylene-methyl acrylate, ethylene-butyl acrylate, or a combination thereof.

[0095] Embodiment 10: A thermal insulation multilayer sheet according to any one of Embodiments 1 to 9, wherein each flexible foam layer independently contains a reinforcing material.

[0096] Embodiment 11: A reinforcing microparticle material comprising carbon black, glass, glass microspheres, lignin, fine metal oxide particles, polyhedral oligomer silsesquioxane, mica, quartz, silica, talc, polyhedral oligomer silsesquioxane, or a combination thereof; a reinforcing fiber material comprising polyester, oxidized polyacrylonitrile, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, glass fiber, high-density polyolefin, ceramic, acrylic resin, fluoropolymer, polyurethane, polyamide, polyimide, or a combination thereof; or a combination of the reinforcing microparticle material and the reinforcing fiber material, wherein the thermal insulation multilayer sheet is as described in Embodiment 9.

[0097] Embodiment 12: The heat insulating multilayer sheet according to any one of Embodiments 1 to 11, wherein the flame retardant component is fine particles in the pores of the flexible foam layer.

[0098] Embodiment 13: The heat insulating multilayer sheet according to any one of Embodiments 1 to 12, wherein the flame retardant component is a flame retardant layer in contact with the surface of the flexible foam layer.

[0099] Embodiment 14: The heat insulating multilayer sheet according to Embodiment 13, wherein the flame retardant layer has a thickness of 0.1 to 2 mm, 0.5 to 1.5 mm, or 0.8 to 1.1 mm.

[0100] Embodiment 15: The heat insulating multilayer sheet according to Embodiment 13 or 14, wherein the flame retardant layer comprises boehmite, aluminum hydroxide, aluminum trihydrate, magnesium hydroxide, an expandable material, or a combination thereof.

[0101] Embodiment 16: A heat insulating multilayer sheet according to any one of Embodiments 13 to 15, wherein the flame retardant layer further comprises a char-forming agent, preferably ammonium polyphosphate, boehmite, cellulose, clay nanocomposite, cyanurate, expandable graphite, huntite, dolomitic, lignin, lignosulfonate, melamine, nanosilica, pentaerythritol, zinc borate, or a combination thereof.

[0102] Embodiment 17: A heat insulating multilayer sheet according to any one of Embodiments 13 to 16, wherein the flame retardant layer further comprises a polymer binder, preferably silicone, polyurethane, ethylene-vinyl acetate, ethylene-methyl acrylate, ethylene-butyl acrylate, or a combination thereof.

[0103] Embodiment 18: A heat insulating multilayer sheet according to any one of Embodiments 1 to 17, wherein the flame retardant component is distributed within a flexible foam layer, and the flame retardant component comprises at least two of the following: aluminum trihydrate, borax, hydrated sodium silicate, magnesium hydroxide, magnesium carbonate hydroxide pentahydrate, trimagnesium phosphate octahydrate, or zinc borate, preferably aluminum trihydrate, borax, hydrated sodium silicate, magnesium hydroxide, magnesium carbonate hydroxide pentahydrate, trimagnesium phosphate octahydrate, or zinc borate.

[0104] Embodiment 19: The heat insulating multilayer sheet according to Embodiment 18, wherein the flame retardant component distributed within the matrix of the flexible foam layer further comprises an organic flame retardant.

[0105] Embodiment 20: A thermal insulation multilayer sheet according to any one of Embodiments 1 to 19, having a thermal conductivity of 0.01 to 0.09 watts / meter Kelvin at 23°C; a thickness of 0.2 to 30 mm, or 0.2 to 20 mm, or 0.2 to 15 mm, or 0.2 to 10 mm, or 0.5 to 10 mm, or 0.5 to 8 mm, or 1 to 6 mm; a density of 6 to 30 pounds / cubic foot (96 to 481 kilograms / cubic meter), 10 to 25 pounds / cubic foot (160 to 400 kilograms / cubic meter), or 15 to 20 pounds / cubic foot (240 to 320 kilograms / cubic meter); or a combination thereof.

[0106] Embodiment 21: An electrochemical cell comprising an insulating multilayer sheet according to any one of Embodiments 1 to 20, disposed on at least a portion of the surface of the electrochemical cell.

[0107] Embodiment 22: The electrochemical cell according to Embodiment 21, wherein an insulating multilayer sheet is arranged on at least two surfaces of the electrochemical cell.

[0108] Embodiment 23: The electrochemical cell according to Embodiment 21 or 22, comprising a prism cell, a pouch cell, or a cylindrical cell, preferably a pouch cell.

[0109] Embodiment 24: A disconnected array comprising at least two electrochemical cells as described in any one of Embodiments 21 to 23.

[0110] Embodiment 25: A battery comprising an electrochemical cell as described in any one of Embodiments 21 to 23 or a disconnected array as described in Embodiment 24.

[0111] Embodiment 26: The battery according to Embodiment 25, further comprising a battery case that at least partially encloses an electrochemical cell or disconnected array.

[0112] Compositions, methods, and articles may consist of, or essentially consist of, any preferred materials, steps, or components disclosed herein as alternatives. Compositions, methods, and articles may further, or alternatively, be formulated to lack or substantially omit any materials (or types), steps, or components that are not otherwise necessary for achieving the function or purpose of the composition, method, or article.

[0113] The terms "a" and "an" indicate the presence of at least one of the items being referred to, not a limitation of quantity. The term "or" means "and / or" unless the context clearly specifies otherwise. Throughout this specification, references to "aspects," "other aspects," etc., mean that certain elements described in relation to an aspect (e.g., features, structure, steps, or characteristics) may be included in at least one aspect described herein and may or may not be present in other aspects. Furthermore, it should be understood that the elements described may be combined in any suitable manner among the various aspects.

[0114] When an element such as a layer, film, region, or substrate is said to be "in contact" with another element, it may also be directly in contact with the other element, or an intervening element may also be present. In contrast, when an element is said to be "directly" in contact with another element, no intervening element is present. When an element is said to be "in contact" with another element, or "in contact" with another element, there are no intervening elements present.

[0115] Unless otherwise specified herein, all test standards are the most current and valid standards as of the filing date of this application, or, if priority is claimed, as of the filing date of the first priority application in which the test standard was made public.

[0116] The endpoints of the entire range covering the same part or property encompass the endpoints, are independently combinable, and include all intermediate points and ranges. For example, the range “up to 25 wt% or 5 to 20 wt%” encompasses the endpoints and all intermediate values ​​of ranges such as “5 to 25 wt%,” for example, 10 to 23 wt%. The terms “first,” “second,” etc., “primary,” “secondary,” etc., when used herein, do not indicate any order, quantity, or importance, but rather are used to distinguish elements from one another. The term “combinations of them” is open-ended, meaning that the list encompasses each element individually, and furthermore, it encompasses combinations of two or more elements in the list, and combinations of at least one element in the list with unnamed similar elements. The term “combination” also includes blends, mixtures, alloys, reaction products, etc.

[0117] Unless otherwise defined, scientific and technical terms used herein have the same meanings as those commonly understood by those skilled in the art in which this disclosure pertains.

[0118] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, in the event of any inconsistency or conflict between terms in this application and terms in any of the incorporated references, the terms from this application shall prevail over the conflicting terms from the incorporated references.

[0119] In the drawings, the widths and thicknesses of layers and regions are exaggerated for clarity and ease of explanation of the specification. Similar reference numbers in the drawings refer to similar elements.

[0120] Exemplary embodiments are described herein with reference to schematic cross-sectional views of idealized embodiments. Therefore, variations from the illustrated shapes should be expected, for example, as a result of manufacturing techniques and / or tolerances. Accordingly, embodiments described herein should not be construed as being limited to specific shapes of regions as illustrated herein, and include, for example, deviations in shape due to manufacturing. For example, regions illustrated or described as flat may typically have rough and / or nonlinear features. Furthermore, illustrated acute angles may be rounded. Accordingly, regions shown in the figures are essentially schematic, and their shapes are not intended to illustrate the exact shapes of regions and are not intended to limit the scope of these claims.

[0121] While specific embodiments are described, alternative methods, modifications, variations, improvements, and substantial equivalents may arise that are not currently foreseeable or foreseeable. Therefore, the attached claims, which are filed and may be modified, are intended to encompass all such alternative methods, modifications, variations, improvements, and substantial equivalents. [Explanation of Symbols]

[0122] 10 Non-porous elastomer barrier layer 12 Flexible foam layer 14 First outer surface 16 The opposite second outer surface 18 pores 20 Inner surface of pores 22 Flexible foam layer 22a First flexible foam layer 22b Second flexible foam layer 24 Flame retardant layer 24a First flame retardant layer 24b Second flame retardant layer 30 Adhesive layer 100 Multilayer Insulation Sheets 102 Multilayer Insulation Sheet 200 pouch cells 202 cells 300 First cell 400 Second cell 500 disconnected arrays 600 Cell Carrier 700 Hot Plate 800 Thermocouple Sensors 900 Mica plate cell analog 1000 multi-cell array 2000 multi-cell array 3000 multi-cell array 4000 Battery 5000 Hot Plate Testing Equipment

Claims

1. A non-porous elastomer barrier layer having a first surface and a second opposite surface; A flexible foam layer disposed on the first surface of the barrier layer; and Contains flame retardant components, The aforementioned flame retardant component is Distributed within the aforementioned flexible foam layer, In contact with the surface of the aforementioned flexible foam layer, Or both, The aforementioned flame retardant component includes aluminum hydroxide, aluminum trihydrate, boehmite, magnesium hydroxide, an expandable material, or a combination thereof. A multi-layer heat-insulating sheet to prevent battery overheating, The thermal insulation multilayer sheet further comprises an additional flexible foam layer disposed on the second surface of the non-porous elastomer barrier layer, and / or The flame retardant component is a flame retardant layer that comes into contact with the surface of the flexible foam layer. Multilayer heat-insulating sheet.

2. The thermal insulation multilayer sheet according to claim 1, further comprising an additional flexible foam layer disposed on the second surface of the non-porous elastomer barrier layer.

3. The non-porous elastomer barrier layer is The measurements were taken at 25°C and 1 atmosphere, and the result was 20 g-mm / m³. ２ - Less than one day, or 10 g-mm / m ２ - Less than one day, or 5 g-mm / m ２ • Water permeability coefficient for less than a day; Tensile stress at 100% elongation of 0.5 to 15 megapascals, measured at 21°C according to ASTM 412; or those combinations A heat insulating multilayer sheet according to claim 1 or claim 2, comprising an elastomer having the following properties.

4. The thermal insulation multilayer sheet according to any one of claims 1 to 3, wherein the non-porous elastomer barrier layer has a thickness of 0.25 to 1 mm or 0.4 to 0.8 mm.

5. The heat insulating multilayer sheet according to any one of claims 1 to 4, wherein the non-porous elastomer barrier layer includes acrylic rubber, butyl rubber, halogenated butyl rubber, epichlorohydrin rubber, ethylene-acrylic rubber, ethylene-butylacrylic rubber, ethylene-diene rubber, ethylene-propylene rubber, ethylene-propylene-diene monomer rubber, ethylene-vinyl acetate, fluororubber, perfluoroelastomer, polyamide, polybutadiene, polychloroprene, polyolefin rubber, polyisoprene, polysulfide rubber, natural rubber, nitrile rubber, low-density polyethylene, polypropylene, thermoplastic polyurethane elastomer, silicone rubber, fluorinated silicone rubber, styrene-butadiene, styrene-isoprene, vinyl rubber, or a combination thereof.

6. The heat insulating multilayer sheet according to any one of claims 1 to 5, wherein the non-porous elastomer barrier layer comprises ethylene-propylene-diene monomer rubber, polychloroprene, or a combination thereof.

7. Each flexible foam layer operates independently. Compressive deflections determined according to ASTM D3574-17 with a 25% deflection, ranging from 0.2 to 125 pounds per square inch (1 to 862 kilopascals), or 0.25 to 20 pounds per square inch (1.7 to 138 kilopascals), or 0.5 to 10 pounds per square inch (3.4 to 68.90.5 kilopascals); Set compression set of 0–15%, 0–10%, or 0–5%, determined at 70°C according to ASTM D 3574-95 Test D; Densities of 5 to 65 pounds / cubic foot (80 to 1,041 kilograms / cubic meter), or 6 to 20 pounds / cubic foot (96 to 320 kilograms / cubic meter), or 8 to 15 pounds / cubic foot (128 to 240 kilograms / cubic meter); or those combinations A heat insulating multilayer sheet according to any one of claims 1 to 6, having the following characteristics.

8. The thermal insulation multilayer sheet according to any one of claims 1 to 7, wherein each flexible foam layer independently has a thickness of 0.1 to 5 mm, 1 to 3 mm, or 1.5 to 2.5 mm.

9. The thermal insulation multilayer sheet according to any one of claims 1 to 8, wherein each flexible foam layer independently comprises silicone, polyurethane, aerogel, ethylene-vinyl acetate, ethylene-methyl acrylate, ethylene-butyl acrylate, or a combination thereof.

10. A thermal insulation multilayer sheet according to any one of claims 1 to 9, wherein each flexible foam layer independently contains a reinforcing material.

11. The aforementioned reinforcing material is Reinforcement particulate materials comprising carbon black, glass, glass microspheres, lignin, fine metal oxide particles, polyhedral oligomer silsesquioxane, mica, quartz, silica, talc, polyhedral oligomer silsesquioxane, or combinations thereof; A reinforcing fiber material wherein the fibers of the reinforcing fiber material include polyester, polyacrylonitrile oxide, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, glass fiber, high-density polyolefin, ceramic, acrylic resin, fluoropolymer, polyurethane, polyamide, polyimide, or a combination thereof; or The heat insulating multilayer sheet according to claim 10, which is a combination of the reinforcing fine particle material and the reinforcing fiber material.

12. The heat insulating multilayer sheet according to any one of claims 1 to 11, wherein the flame retardant component is fine particles in the pores of the flexible foam layer.

13. The heat insulating multilayer sheet according to any one of claims 1 to 12, wherein the flame retardant component is a flame retardant layer that comes into contact with the surface of the flexible foam layer.

14. The heat insulating multilayer sheet according to claim 13, wherein the flame retardant layer has a thickness of 0.1 to 2 mm, 0.5 to 1.5 mm, or 0.8 to 1.1 mm.

15. The heat insulating multilayer sheet according to any one of claims 13 to 14, wherein the flame retardant layer further comprises a char-forming agent.

16. The heat insulating multilayer sheet according to any one of claims 13 to 15, wherein the flame retardant layer further comprises a polymer binder.

17. The flame retardant component is distributed within the matrix of the flexible foam layer, and the flame retardant component is A heat insulating multilayer sheet according to any one of claims 1 to 16, comprising aluminum trihydrate, borax, hydrated sodium silicate, magnesium hydroxide, magnesium carbonate hydroxide pentahydrate, trimagnesium phosphate octahydrate, or zinc borate.

18. The heat insulating multilayer sheet according to claim 17, wherein the flame retardant component distributed within the matrix of the flexible foam layer further comprises an organic flame retardant.

19. Thermal conductivity of 0.01 to 0.09 watts / meter-kelvin at 23°C; Thickness of 0.2 to 30 mm, or 0.2 to 20 mm, or 0.2 to 15 mm, or 0.2 to 10 mm, or 0.5 to 10 mm, or 0.5 to 8 mm, or 1 to 6 mm; Densities of 6 to 30 pounds / cubic foot (96 to 481 kilograms / cubic meter), 10 to 25 pounds / cubic foot (160 to 400 kilograms / cubic meter), or 15 to 20 pounds / cubic foot (240 to 320 kilograms / cubic meter); or those combinations A heat insulating multilayer sheet according to any one of claims 1 to 18, having the characteristics of the claim.

20. An electrochemical cell comprising an insulating multilayer sheet according to any one of claims 1 to 19, disposed on at least a portion of the surface of the electrochemical cell.

21. The electrochemical cell according to claim 20, wherein the heat insulating multilayer sheet is arranged on at least two surfaces of the electrochemical cell.

22. The electrochemical cell according to claim 20 or 21, comprising a prism cell, a pouch cell, or a cylindrical cell.

23. A disconnected array comprising at least two electrochemical cells according to any one of claims 20 to 22.

24. A battery comprising an electrochemical cell according to any one of claims 20 to 22 or a disconnected array according to claim 23.

25. The battery according to claim 24, further comprising a battery case that at least partially encloses the electrochemical cell or the disconnected array.

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