Heat control members

Abstract

An example of a heat control member includes a thermal insulation layer and a barrier material in contact with at least a portion of the thermal insulation layer. The thermal insulation layer includes a reinforcement material and an aerogel framework incorporated with the reinforcement material. The barrier material is selected from the group consisting of i) aluminum, silicon, and oxygen; ii) nitrogen and one of silicon or boron; iii) zirconia; and iv) a carbide.

Description

AAI-105-B-PCT (1207-WO01) 1 HEAT CONTROL MEMBERS CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application S.N. 63 / 649,918, filed May 20, 2024 and U.S. Provisional Application S.N.63 / 653,551, filed May 30, 2024, the content of each of which is incorporated by reference herein in its entirety. BACKGROUND

[0002] Low-density aerogel materials are widely considered to be the best solid insulators available. Aerogels function as insulators primarily by minimizing conduction (e.g., the low structural density results in a tortuous path for energy transfer through the solid framework), convection (e.g., large pore volumes and very small pore sizes result in minimal convection), and radiation (e.g., infrared (IR) absorbing or scattering dopants are readily dispersed throughout the aerogel matrix). Aerogels can be used in a broad range of applications, including: heating and cooling insulation, acoustics insulation, electronic dielectrics, aerospace, energy storage and production, and filtration. Furthermore, aerogel materials display many other interesting acoustic, optical, mechanical, and chemical properties that make them abundantly useful in various insulation and non-insulation applications. SUMMARY

[0003] Various heat control members are disclosed herein. One aspect of the heat control member includes a thermal insulation layer and a barrier material in contact with at least a portion of the thermal insulation layer. The thermal insulation layer includes a reinforcement material and an aerogel framework incorporated with the reinforcement material. This and other aspects of the heat control member disclosed herein may be positioned, in one application, between adjacent battery cells. In this application, the addition of the barrier material improves the flame and gritAAI-105-B-PCT (1207-WO01) 2 performance of the heat control member. The flame and grit performance refers to the heat control member’s ability to withstand thermal degradation upon exposure to a flame at a certain standoff distance and to withstand breakthrough upon exposure to a grit feed at the same standoff distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Features of aspects of the present disclosure will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to similar, though perhaps not identical, components. For the sake of brevity, reference numerals or features having a previously described function may or may not be described in connection with other drawings in which they appear.

[0005] Fig.1A is a schematic cross-sectional view of a heat control member illustrating various aspects disclosed herein;

[0006] Fig.1B is a schematic cross-sectional view of a heat control member with a free standing barrier layer illustrating various aspects disclosed herein;

[0007] Fig.1C is a schematic cross-sectional view of a heat control member with a heat diffusion layer between a barrier layer and a thermal insulation layer illustrating various aspects disclosed herein;

[0008] Fig.2A is a schematic cross-sectional view of another heat control member illustrating various aspects disclosed herein;

[0009] Fig.2A’ is an enlarged view of a portion of Fig.2A depicting an alternative aspect of the heat control member including a heat diffusion layer;

[0010] Fig.2A’’ is an enlarged view of a portion of Fig.2A depicting an alternative aspect of the heat control member including a barrier layer between two heat diffusion layers;

[0011] Fig.2A’’’ is an enlarged view of a portion of Fig.2A depicting an alternative aspect of the heat control member including a free standing barrier layer;

[0012] Fig.2B is a schematic cross-sectional view of yet another heat control member illustrating various aspects disclosed herein;AAI-105-B-PCT (1207-WO01) 3

[0013] Fig.3A and Fig.3B are macro photographic images of the front and back, respectively, of one example heat control member after a flame and grit test;

[0014] Fig.3C and Fig.3D are macro photographic images of the front and back, respectively, of another example heat control member after a flame and grit test;

[0015] Fig.4A and Fig.4B are schematic cross-sectional views of two experimental heat control members disclosed herein;

[0016] Fig.4C is a graph of back side temperature (°C, Y axis) as a function of time (minutes, X axis) comparing the effectiveness of the two experimental heat control members schematically illustrated in Fig.4A and Fig.4B;

[0017] Fig.5A is a schematic cross-sectional view of an experimental heat control member disclosed herein;

[0018] Fig.5B is a graph illustrating experimental results of backside temperatures (°C, Y axis) of the experimental heat control member illustrated in Fig. 5A as a function of barrier material (in terms of thermal resistance °K / W, X axis) as disclosed herein;

[0019] Fig.6A is a schematic illustration of a test configuration for simulating a thermal runaway event;

[0020] Fig.6B is a temperature graph illustrating a cell temperature in a simulated thermal runaway event conducted in the test configuration of Fig.6A, in which adjacent cells were separated by a commercially available thermal barrier as disclosed herein; and

[0021] Fig.6C is a temperature graph illustrating a cell temperature in a simulated thermal runaway event conducted in the test configuration of Fig.6A, in which adjacent cells were separated by an experimental thermal barrier as disclosed herein. DETAILED DESCRIPTION

[0022] Aerogels are a class of porous materials with open-cells that include a framework of interconnected structures, with a corresponding network of pores integrated within the framework, and an interstitial phase within the network of poresAAI-105-B-PCT (1207-WO01) 4 which is primarily comprised of gases, such as air. Aerogels are typically characterized by a low density, a high porosity, a large surface area, and small pore sizes. Aerogels can be distinguished from other porous materials by their physical and structural properties.

[0023] Aerogel materials possess from about two times to about six times the thermal resistance of other common types of insulation, e.g., foams, fiberglass, etc. Aerogels can increase effective shielding and thermal insulation without substantially increasing the thickness of the insulation and without adding additional weight. Thus, aerogels can be incorporated into heat control members, such as separators, to reduce thermal runaway in small space applications, such as battery modules, without increasing thickness and / or weight. Aspects disclosed herein also enhance the resistance to flame and grit damage. One type of grit damage is particle bombardments of a heat control member by the thermal runaway ejecta from a battery during a thermal runaway event.

[0024] In the various aspects disclosed herein, the aerogel framework is incorporated into a heat control member that also includes a barrier material, a heat diffusion layer, or both. The combination of the aerogel framework, the barrier material and / or the heat diffusion layer provides the heat control member with i) thermal insulation, which enables reliable control of heat flow from heat-generating parts used in conjunction with the heat control member, ii) flame retardance, which helps to reduce fire propagation, and iii) abrasion resistance, which helps to reduce mechanical degradation that can result from grit (e.g., that may be generated during a battery fire, also referred to as a thermal runaway event). Thus, aspects of heat control members described herein exhibit improved flame and grit performance compared, for example, to mica sheets, which have been used to impart grit resistance.

[0025] Definitions

[0026] Terms used herein will be understood to take on their ordinary meaning in the relevant art unless specified otherwise. Several terms used herein and their meanings are set forth below.AAI-105-B-PCT (1207-WO01) 5

[0027] As used herein, the conjunction “and” is intended to be inclusive and the conjunction “or” is not intended to be exclusive unless otherwise indicated. For example, the phrase “or, alternatively” is intended to be exclusive.

[0028] The singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0029] The terms comprising, having, including, containing and various forms of these terms are synonymous with each other and are meant to be equally broad, open-ended terms.

[0030] It is to be understood that the ranges provided herein include the stated range and any value or sub-range within the stated range, as if such values or sub- ranges were explicitly recited. For example, a range of about 50 microns (µm) to about 500 microns (µm) should be interpreted to include not only the explicitly recited limits of about 50 microns (µm) to about 500 microns (µm), but also to include individual values, such as about 150 µm, about 300 µm, etc., and sub-ranges, such as from about 100 µm to about 400 µm, from about 75 µm to about 475 µm, etc.

[0031] As used herein, the term “about” refers to a degree of deviation typical for a particular property, composition, amount, value or parameter as identified; such as deviations based on experimental errors, measurement errors, approximation errors, calculation errors, standard deviations from a mean value, routine minor adjustments, and so forth. As an example, when “about” and / or “substantially” are / is utilized to describe a value, they are meant to encompass minor variations (up to + / - 10%) from the stated value.

[0032] Reference throughout the specification to “one example”, “another example”, “an example”, “an aspect,” “another aspect,” and so forth, means that a particular element (e.g., feature, structure, and / or characteristic) described in connection with the example is included in at least one example described herein, and may or may not be present in other examples. In addition, it is to be understood that the described elements for any example may be combined in any suitable manner in the various examples unless the context clearly dictates otherwise.AAI-105-B-PCT (1207-WO01) 6

[0033] As used herein, a “barrier material precursor” refers to an aqueous or a non-aqueous dispersion that contains a barrier material.

[0034] The term “barrier material” refers to a material that improves resistance to flame and / or grit. The barrier material may be deposited with a binder that forms a matrix, which immobilizes the barrier material therein. The matrix, and thus the binder material, may be formed within pores of another material and / or may form discontinuous patches on a major surface of the other material or a continuous layer on a major surface of the other material.

[0035] The term “in contact with” means that two components physically touch each other. Examples of such contact include layered components, or one component penetrating the pores of another component, or one component coating another component, or any combination of these (e.g., a barrier material coats fibers at a major surface of a reinforcement material and also penetrates into at least some pores of the reinforcement material). The term “on” means components that are either in direct contact or indirect contact with one another (e.g., two layers separated by an intervening layer).

[0036] Within the context of the present disclosure, the term “aerogel” or “aerogel material” refers to a gel including a framework of interconnected structures, with a corresponding network of interconnected pores integrated within the framework, and containing gases, such as air, as a dispersed interstitial medium; and which is characterized by the following physical and structural properties (according to Nitrogen Porosimetry Testing) attributable to aerogels: (a) an average pore diameter ranging from about 2 nm to about 100 nm, (b) a porosity of at least 80% or more, and (c) a surface area of about 20 m2 / g or more. Aerogel materials of the present disclosure thus include any aerogels or other open-celled compounds which satisfy the defining elements set forth in this paragraph; including compounds which can be otherwise categorized as xerogels, cryogels, ambigels, microporous materials, and the like.

[0037] Aerogel materials may also be further characterized by additional physical properties, including: (d) a pore volume of about 2.0 mL / g or more, preferably about 3.0 mL / g or more; (e) a density of about 0.50 g / cc or less, preferably about 0.25AAI-105-B-PCT (1207-WO01) 7 g / cc or less; and (f) at least 50% of the total pore volume comprising pores having a pore diameter of between 2 and 50 nm; though satisfaction of these additional properties (d-f) is not required for the characterization of a compound as an aerogel material.

[0038] The term “innovative processing and extraction techniques” refers to methods of replacing a liquid interstitial phase in a wet-gel material with a gas, such as air, in a manner that minimizes collapse of the pores and shrinkage of the framework structure of the gel. Drying techniques, such as ambient pressure evaporation, often introduce strong capillary pressures and other mass transfer limitations at the liquid- vapor interface of the interstitial phase being evaporated or removed. The strong capillary forces generated by liquid evaporation or removal can cause significant pore shrinkage and framework collapse within the gel material. The use of innovative processing and extraction techniques during the extraction of a liquid interstitial phase reduces the negative effects of capillary forces on the pores and the framework of a gel during liquid phase extraction.

[0039] In certain aspects, an innovative processing and extraction technique uses near critical or super critical fluids, or near critical or super critical conditions, to extract the liquid interstitial phase from a wet-gel material. This can minimize capillary forces and / or framework perturbation, thereby preserving the nanoporous structure of the wet gel in the dried gel phase. This can be accomplished by removing the liquid interstitial phase from the gel near or above the critical point of the liquid or mixture of liquids. Co-solvents and solvent exchanges can be used to enhance the near critical or super critical fluid extraction process.

[0040] In certain aspects, an innovative processing and extraction technique includes the modification of the gel framework to reduce the irreversible effects of capillary pressures and other mass transfer limitations at the liquid-vapor interface. This example can include the treatment of a gel framework with a hydrophobizing agent, or other functionalizing agents, which allow a gel framework to withstand or recover from any collapsing forces during liquid phase extraction conducted below the critical point of the liquid interstitial phase. This example can also include theAAI-105-B-PCT (1207-WO01) 8 incorporation of functional groups or framework elements which provide a framework modulus that is sufficiently high to withstand or recover from collapsing forces during liquid phase extraction conducted below the critical point of the liquid interstitial phase.

[0041] Within the context of the present disclosure, the terms “framework” or “framework structure” refer to the network of interconnected oligomers, polymers or colloidal particles that form the solid structure of a gel or an aerogel. The polymers or particles that make up the framework structures typically have a diameter of about 100 angstroms. However, framework structures of the present disclosure can also include networks of interconnected oligomers, polymers or colloidal particles of all diameter sizes that form the solid structure within in a gel or aerogel.

[0042] Furthermore, the terms “silica-based aerogel” or “silica-based framework” refer to an aerogel framework in which silica comprises at least 50% (by weight) of the oligomers, polymers or colloidal particles that form the solid framework structure within in the gel or aerogel.

[0043] Within the context of the present disclosure, the term “aerogel composition” refers to any composite material which includes aerogel material as a component of the composite. Aspects of aerogel compositions include: fiber- reinforced aerogel composites; aerogel composites which include additive elements, such as opacifiers; aerogel-foam composites; aerogel-polymer composites; and composite materials which incorporate aerogel particulates, particles, granules, beads, or powders into a solid or semi-solid material, such as binders, resins, cements, foams, polymers, or similar solid materials.

[0044] Also as used herein, the term “monolithic” refers to aerogel materials in which a majority (by weight) of the aerogel included in the aerogel material or composition is in the form of a unitary interconnected aerogel nanostructure. Monolithic aerogel materials include aerogel materials which are initially formed to have a unitary interconnected gel or aerogel nanostructure, but which are subsequently cracked, fractured or segmented into non-unitary aerogel nanostructures. Monolithic aerogel materials are differentiated from particulate aerogel materials. The term “particulate aerogel material” refers to aerogel materialsAAI-105-B-PCT (1207-WO01) 9 in which a majority (by weight) of the aerogel included in the aerogel material is in the form of particulates, particles, granules, beads, or powders, which can be combined or compressed together, but which lack an interconnected aerogel nanostructure between individual particles.

[0045] Within the context of the present disclosure, the term “reinforced aerogel composition” refers to aerogel compositions which include a reinforcing phase within the aerogel material, but which is not part of the aerogel framework. The reinforcing phase can be any material which provides increased flexibility, resilience, conformability or structural stability to the aerogel material. Aspects of suitable reinforcing materials include: open-cell foam reinforcement materials, closed-cell foam reinforcement materials, open-cell membranes, honeycomb reinforcement materials, polymeric reinforcement materials, and fiber reinforcement materials such as discrete fibers, woven materials, non-woven materials, battings, webs, mats, and felts. Additionally, fiber-based reinforcements may be combined with the other reinforcing material(s), and can be oriented continuously throughout or in select parts of the composition.

[0046] Within the context of the present disclosure, the term “fiber-reinforced aerogel composition” refers to a reinforced aerogel composition which comprises a fiber reinforcement material as a reinforcing phase. Aspects of fiber reinforcement materials include discrete fibers, woven materials, non-woven materials, battings, webs, mats, felts, or combinations thereof. Fiber reinforcement materials can include a range of materials, such as: polyesters, polyolefin terephthalates, poly(ethylene) naphthalate, polycarbonates, regenerated cellulose (e.g., rayon), polyamide (e.g., nylon(s)), cotton (e.g., LYCRA® manufactured by DuPont), carbon (e.g., graphite), polyacrylonitriles (PAN), oxidized PAN, uncarbonized heat treated PANs (such as those manufactured by SGL carbon), fiberglass based material (such as S-glass, 901 glass, 902 glass, 475 glass, E-glass,) silica based fibers (including quartz, (e.g., QUARTZEL® manufactured by Saint-Gobain), pure silica (e.g., Q-FELT® and Q- FIBER® felt manufactured by Johns Manville), alumina / silica (e.g., SAFFIL® manufactured by Saffil), ceramics (e.g., DURABLANKET® and DURABACK®, eachAAI-105-B-PCT (1207-WO01) manufactured by Unifrax) and other silica fibers), polyaramid fibers (e.g., KEVLAR® and NOMEX®, each manufactured by DuPont, SONTARA® manufactured by Glatfelter, and CONEX™ manufactured by Taijin), polyolefins (e.g., TYVEK® manufactured by DuPont, DYNEEMA® manufactured by DSM, and SPECTRA® manufactured by Honeywell), other polypropylene fibers (e.g., TYPAR™ and XAVAN® both manufactured by DuPont), fluoropolymers, such as polytetrafluoroethylene (PTFE) available under the trade names TEFLON® (manufactured by DuPont), GORE-TEX® (manufactured by W.L. GORE), Silicon carbide fibers (e.g., NICALON™ manufactured by COI Ceramics), other ceramic fibers (e.g., NEXTEL® manufactured by 3M), acrylic polymers, fibers of wool, silk, hemp, leather, or suede, liquid crystal materials (e.g., ZYLON® PBO fibers manufactured by Tyobo and VECTRAN™ manufactured by Kuraray), polyurethanes, wood fibers, boron fibers, metal or metal alloy fibers (e.g., aluminum, iron, stainless steel), and thermoplastics (e.g., polyether ether ketone (PEEK), poly(ether sulfone) (PES), polyethyleneimine (PEI), polyetherketones (PEK), and polyphenylene sulfide (PPS)). Some aspects of fiber reinforcement materials include the fibers and a binder material, which is either intermingled with the fibers or coated on the fibers. As specific examples, the fiber reinforcement material is a glass fiber veil with either a polyvinyl alcohol (PVA) or polyester binder that is sprayed onto the fibers before entanglement.

[0047] The terms “additive” or “additive element,” as used herein, refer to materials which can be added to an aerogel composition before, during, or after the production of the aerogel. Additives can be added to alter or improve desirable properties in an aerogel, or to counteract undesirable properties in an aerogel. Additives are typically added to an aerogel material either prior or during gelation. Examples of additives include, but are not limited to: microfibers, fillers, reinforcing agents, stabilizers, thickeners, elastic compounds, opacifiers, coloring or pigmentation compounds, radiation absorbing compounds, radiation reflecting compounds, corrosion inhibitors, thermally conductive components, phase change materials, pH adjustors, redox adjustors, HCN mitigators, off-gas mitigators, electrically conductive compounds, electrically dielectric compounds, magnetic compounds, radar blockingAAI-105-B-PCT (1207-WO01) components, hardeners, anti-shrinking agents, and other aerogel additives known to those in the art. Other examples of additives include smoke suppressants and fire suppressants. U.S. Patent Application Publication No.2007 / 0272902 A1 (paragraphs 8 and 10-39) includes teachings of smoke suppressants and fire suppressants, and is hereby incorporated by reference according to the individually cited paragraphs.

[0048] Within the context of the present disclosure, the terms “resilient” and “resilience” refer to the ability of an aerogel material or composition to at least partially return to an original form or dimension following deformation through compression, flexing, or bending. Resilience may be complete or partial, and it may be expressed in terms of percentage return. An aerogel material or composition of the present disclosure preferably has a resilience of more than 25%, more than 50%, more than 60%, more than 70%, more than 75%, more than 80%, more than 85%, more than 90%, or more than 95% return to an original form or dimension following a deformation. Likewise, the terms “classified resilient” and “classified as resilient” refer to aerogel materials or compositions of the present disclosure which can be classified as resilient flexible according to ASTM classification standard C1101 (ASTM International, West Conshohocken, PA).

[0049] Within the context of the present disclosure, the terms “thermal conductivity” and “TC” refer to a measurement of the ability of a material or composition to transfer heat between two surfaces on either side of the material or composition, with a temperature difference between the two surfaces. Thermal conductivity is specifically measured as the heat energy transferred per unit time and per unit surface area, divided by the temperature difference. Thermal conductivity is typically recorded in SI units as mW / m*K (milliwatts per meter * Kelvin). The thermal conductivity of a material may be determined by methods known in the art, including, but not limited to: Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus (ASTM C518, ASTM International, West Conshohocken, PA); a Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus (ASTM C177, ASTM International, West Conshohocken, PA); a Test Method forAAI-105-B-PCT (1207-WO01) Steady-State Heat Transfer Properties of Pipe Insulation (ASTM C335, ASTM International, West Conshohocken, PA); a Thin Heater Thermal Conductivity Test (ASTM C1114, ASTM International, West Conshohocken, PA); Determination of thermal resistance by means of guarded hot plate and heat flow meter methods (EN 12667, British Standards Institution, United Kingdom); or Determination of steady-state thermal resistance and related properties - Guarded hot plate apparatus (ISO 8203, International Organization for Standardization, Switzerland). Within the context of the present disclosure, thermal conductivity measurements are acquired according to ASTM C177 standards, at a temperature of about 37.5°C at atmospheric pressure, and a compression of about 2 psi, unless otherwise stated. Preferably, aerogel materials or compositions of the present disclosure have a thermal conductivity of about 50 mW / mK or less, about 40 mW / mK or less, about 30 mW / mK or less, about 25 mW / mK or less, about 20 mW / mK or less, about 18 mW / mK or less, about 16 mW / mK or less, about 14 mW / mK or less, about 12 mW / mK or less, about 10 mW / mK or less, about 5 mW / mK or less, or in a range between any two of these values.

[0050] Within the context of the present disclosure, the term “density” refers to a measurement of the mass per unit volume of an aerogel material or composition. The term “density” generally refers to the true density of an aerogel material, as well as the bulk density of an aerogel composition. Density is typically recorded as kg / m3or g / cc. The density of an aerogel material or composition may be determined by methods known in the art, including, as examples: Standard Test Method for Dimensions and Density of Preformed Block and Board–Type Thermal Insulation (ASTM C303, ASTM International, West Conshohocken, PA); Standard Test Methods for Thickness and Density of Blanket or Batt Thermal Insulations (ASTM C167, ASTM International, West Conshohocken, PA); or Determination of the apparent density of preformed pipe insulation (ISO 18098, International Organization for Standardization, Switzerland). Within the context of the present disclosure, density measurements are acquired according to ASTM C167 standards, unless otherwise stated. Preferably, aerogel materials or compositions of the present disclosure have a density of about 0.60 g / cc or less, about 0.50 g / cc or less, about 0.40 g / cc or less, about 0.30 g / cc or less, aboutAAI-105-B-PCT (1207-WO01) 0.25 g / cc or less, about 0.20 g / cc or less, about 0.18 g / cc or less, about 0.16 g / cc or less, about 0.14 g / cc or less, about 0.12 g / cc or less, about 0.10 g / cc or less, about 0.05 g / cc or less, about 0.01 g / cc or less, or in a range between any two of these values.

[0051] Within the context of the present disclosure, the term “hydrophobicity” refers to a measurement of the ability of an aerogel material or composition to repel water.

[0052] Hydrophobicity of an aerogel material or composition can be expressed in terms of the liquid water uptake. Within the context of the present disclosure, the term “liquid water uptake” refers to a measurement of the potential of an aerogel material or composition to absorb or otherwise retain liquid water. Liquid water uptake can be expressed as a percent (by weight or by volume) of water which is absorbed or otherwise retained by an aerogel material or composition when exposed to liquid water under certain measurement conditions. The liquid water uptake of an aerogel material or composition may be determined by methods known in the art, including, but not limited to: Standard Test Method for Determining the Water Retention (Repellency) Characteristics of Fibrous Glass Insulation (ASTM C1511, ASTM International, West Conshohocken, PA); Standard Test Method for Water Absorption by Immersion of Thermal Insulation Materials (ASTM C1763, ASTM International, West Conshohocken, PA); Thermal insulating products for building applications: Determination of short term water absorption by partial immersion (EN 1609, British Standards Institution, United Kingdom). Within the context of the present disclosure, measurements of liquid water uptake are acquired according to ASTM C1511 standards, under ambient pressure and temperature, unless otherwise stated. Preferably, aerogel materials or compositions of the present disclosure can have a liquid water uptake, according to ASTM C1511, of about 100 wt% or less, about 80 wt% or less, about 60 wt% or less, about 50 wt% or less, about 40 wt% or less, about 30 wt% or less, about 20 wt% or less, about 15 wt% or less, about 10 wt% or less, about 8 wt% or less, about 3 wt% or less, about 2 wt% or less, about 1 wt% or less, about 0.1 wt% or less, or in a range between any two of these values. Aerogel materials or compositions of the presentAAI-105-B-PCT (1207-WO01) disclosure can have a liquid water uptake, according to ASTM C1763, of about 100 wt% or less, about 80 wt% or less, about 60 wt% or less, about 50 wt% or less, about 40 wt% or less, about 30 wt% or less, about 20 wt% or less, about 15 wt% or less, about 10 wt% or less, about 8 wt% or less, about 3 wt% or less, about 2 wt% or less, about 1 wt% or less, about 0.1 wt% or less, or in a range between any two of these values. An aerogel material or composition which has improved liquid water uptake relative to another aerogel material or composition will have a lower percentage of liquid water uptake / retention relative to the reference aerogel materials or compositions.

[0053] Aerogels are described as a framework of interconnected structures which are most commonly comprised of interconnected oligomers, polymers or colloidal particles. An aerogel framework can be made from a range of precursor materials, including: inorganic precursor materials (such as precursors used in producing silica-based aerogels); organic precursor materials (such precursors used in producing carbon-based aerogels); hybrid inorganic / organic precursor materials; and combinations thereof. Within the context of the present disclosure, the term “amalgam aerogel” refers to an aerogel produced from a combination of two or more different gel precursors.

[0054] Inorganic aerogels are generally formed from metal oxide or metal alkoxide materials. The metal oxide or metal alkoxide materials can be based on oxides or alkoxides of any metal that can form oxides. Such metals include: silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium, cerium, and the like. Inorganic silica aerogels are traditionally made via the hydrolysis and condensation of silica-based alkoxides (such as tetraethoxylsilane), or via gelation of silicic acid or water glass. Other relevant inorganic precursor materials for silica based aerogel synthesis include: metal silicates, such as sodium silicate or potassium silicate, alkoxysilanes, partially hydrolyzed alkoxysilanes, tetraethoxylsilane (TEOS), partially hydrolyzed TEOS, condensed polymers of TEOS, tetramethoxylsilane (TMOS), partially hydrolyzed TMOS, condensed polymers of TMOS, tetra-n-propoxysilane, partially hydrolyzed and / or condensed polymers of tetra-n-propoxysilane,AAI-105-B-PCT (1207-WO01) polyethylsilicates, partially hydrolyzed polyethysilicates, monomeric alkylalkoxy silanes, bis-trialkoxy alkyl or aryl silanes, polyhedral silsesquioxanes, or combinations thereof.

[0055] In certain aspects of the present disclosure, pre-hydrolyzed TEOS, such as DYNASYLAN® SILBOND® H-5 (Evonik), which is hydrolyzed with a water / silica ratio of about 1.9-2, may be used as commercially available or may be further hydrolyzed prior to incorporation into the gelling process. Partially hydrolyzed TEOS or TMOS, such as polyethysilicate (DYNASYLAN® SILBOND® 40) or polymethylsilicate may also be used as commercially available or may be further hydrolyzed prior to incorporation into the gelling process.

[0056] Inorganic aerogels can also include gel precursors which include at least one hydrophobic group, such as alkyl metal alkoxides, cycloalkyl metal alkoxides, and aryl metal alkoxides, which can impart or improve certain properties in the gel, such as stability and hydrophobicity. Inorganic silica aerogels can specifically include hydrophobic precursors, such as alkylsilanes or arylsilanes. Hydrophobic gel precursors can be used as primary precursor materials to form the framework of a gel material. However, hydrophobic gel precursors are more commonly used as co- precursors in combination with simple metal alkoxides in the formation of amalgam aerogels. Hydrophobic inorganic precursor materials for silica based aerogel synthesis include: trimethyl methoxysilane [TMS], dimethyl dimethoxysilane [DMS], methyl trimethoxysilane [MTMS], trimethyl ethoxysilane, dimethyl diethoxysilane [DMDS], methyl triethoxysilane [MTES], ethyl triethoxysilane [ETES], diethyl diethoxysilane, ethyl triethoxysilane, propyl trimethoxysilane, propyl triethoxysilane, phenyl trimethoxysilane, phenyl triethoxysilane [PhTES], hexamethyldisilazane and hexaethyldisilazane, and the like.

[0057]

[0058] Heat Control Members and Methods of Making the Same

[0059] Fig.1A, Fig.1B, Fig.1C, Fig.2A, and Fig.2B illustrate aspects of the heat control member 10A, 10A’, 10A’’, 10B, 10C disclosed herein.AAI-105-B-PCT (1207-WO01)

[0060] In the aspect shown in Fig.1A, the heat control member 10A includes a hydrophobic thermal insulation layer 12 and a barrier material 14 in contact with at least a portion of the hydrophobic thermal insulation layer 12.

[0061] The hydrophobic thermal insulation layer 12 is an example of the reinforced aerogel composition disclosed herein because it includes a reinforcement material 16 and an aerogel framework 18 incorporated with the reinforcement material 16.

[0062] In various aspects, the fiber reinforcement materials set forth herein may be used as the reinforcement material 16 in the aspect of Fig.1A. In one aspect, the reinforcement material 16 is selected from the group consisting of a non-woven fiber batting, a glass fiber veil, a glass fiber veil including a binder, and aluminosilicate fibers. Aspects also may include, the glass fiber veil includes non-woven glass fibers that are individually coated with a polyvinyl alcohol or polyester binder. In an aspect, the reinforcement material 16 is a continuous sheet of interconnected or interlaced fibers.

[0063] As shown in Fig.1A, the reinforcement material 16 includes a first major surface S1, a second major surface S2, and a thickness T therebetween. The thickness T may be 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less. In aspects where the heat control member 10A is to be used as a divider between battery cells, the thickness may be 5 mm or less. Fig.1A illustrates an aspect in which the barrier material 14 is in contact with the first major surface S1and incorporated into a first portion P1of the thickness T and the aerogel framework 18 is in contact with the second major surface S2 and a second portion P2 of the thickness T that is greater than the first portion P1of the thickness T.

[0064] As mentioned, the aerogel framework 18 is incorporated with the reinforcement material 16 such that the aerogel framework 18 is in contact with the second major surface S2. As will be described in detail below, the innovative processing and extraction technique used to form the aerogel framework 18 is performed such that the aerogel precursors (in the form of a sol-gel solution) are castAAI-105-B-PCT (1207-WO01) into the reinforcement material 16 at the second major surface S2. Thus, the aerogel framework 18 is formed within the portion P2.

[0065] The thickness of the portion P2 is a fraction of the total thickness T and is greater than the thickness of portion P1 that includes the barrier material 14. In an aspect, the thickness of the portion P2is greater than 500 µm and is up to 5 mm (depending upon the thickness T). Additionally, the depth of the penetration of the aerogel precursors may vary across the second major surface S2, and thus the total thickness of the portion P2may vary across the second major surface S2.

[0066] The aerogel framework 18 may be any of the compositions set forth herein, including the inorganic aerogels, the organic aerogels, or the organic / inorganic hybrid aerogels. Any of these aerogels may be exposed to any of the treatment processes disclosed herein to impart or improve the hydrophobicity. Thus, in some aspects, the aerogel framework 18 is hydrophobic. In a specific aspect, the aerogel framework 18 may be a hydrophobic silica-based framework, such as an inorganic silica aerogel formed primarily from alcohol solutions of hydrolyzed silicate esters formed from silicon alkoxides. However, the disclosure as a whole may be practiced with any other aerogel compositions known to those in the art, and is not limited to any one precursor material or amalgam mixture of precursor materials.

[0067] Several barrier materials 14 are described herein that can be used in the heat control member 10A. In one aspect, the barrier material 14 includes aluminum, silicon, and oxygen. In aspects, this barrier material 14 may be composed of aluminosilicate fibers, silicon dioxide, and titanium dioxide. This barrier material 14 may be formed from an aqueous composition composed of from 40 wt% to about 60 wt% of the aluminosilicate fibers, from about 40 wt% to about 60 wt% of a liquid binder (including from about 10 wt% to about 20 wt% of silicon dioxide in water e.g., a sodium silicate or “water glass” liquid binder), and less than 1 wt% of titanium dioxide. In another aspect, the barrier material 14 includes nitrogen and one of silicon or boron. In still another aspect, the barrier material 14 includes zirconia (zirconium and oxygen). This barrier material 14 may be formed from the combination of an aqueous silicate solution (the concentration of which ranges from about 10 wt% to about 20AAI-105-B-PCT (1207-WO01) wt%), an aqueous aluminosilicate fiber suspension (the concentration of which ranges from about 10 wt% to about 20 wt%), an aqueous zirconium dioxide suspension (the concentration of which ranges from about 30 wt% to about 50 wt%), and additional water. In yet another aspect, the barrier material 14 includes a carbide. As one aspect, this barrier material 14 may be formed from the combination of silicon carbide and a liquid binder at a ratio ranging from 4:1 to 1:1, where the liquid binder includes from about 40 wt% to about 60 wt% of silicon dioxide in water). In still a further aspect, the barrier material 14 includes alumina. This barrier material 14 may be formed from the combination of an aqueous aluminum oxide suspension (the concentration of which ranges from about 50 wt% to about 70 wt%), an aqueous monoaluminum phosphate suspension (the concentration of which ranges from about 20 wt% to about 25 wt%), and additional water. In other aspects, the barrier material 14 may be formed from the combination of a kaolin, metakaolin, halloysite, or other aluminosilicate clay suspended in a liquid binder at a ratio ranging from 4:1 to 1:1, where the liquid binder includes from about 40 wt% to about 60 wt% of silicon dioxide (e.g., sodium silicate or “water glass”) in water. In other aspects, commercially available aqueous and non-aqueous dispersions and / or solutions may be used to apply barrier and / or heat diffusion layer(s) as described herein.

[0068] The barrier material 14 is in contact with the first major surface S1 of the reinforcement material 16. While the barrier material 14 is shown in Fig.1A as a layer along the first major surface S1, it is to be understood that the barrier material 14 is incorporated into a portion (shown as portion P1) of the thickness T. More particularly, the barrier material 14 may coat some of the fibers at the first major surface S1 and may also penetrate into pores / voids / spaces between the fibers at the first major surface S1and extending into the portion P1. The thickness of the portion P1is a fraction of the total thickness of the barrier material 14 that is present. While not shown in Fig.1A, the portion P1 may be thicker than a portion P3 of the barrier material 14 that is positioned on the first major surface S1(i.e., not penetrating into the thickness T). In one aspect, the total thickness of the barrier material 14 (i.e., thickness of the portion P1 + thickness of the portion P3) ranges from about 50 micronsAAI-105-B-PCT (1207-WO01) (µm) to about 500 microns (µm). In another aspect, the total thickness of the barrier material 14 (i.e., thickness of the portion P1+ thickness of the portion P3) ranges from about 300 µm to about 400 µm. Additionally, because the first major surface S1 may not be flat and because the depth of the penetration of the barrier material 14 into the portion P1may vary across the first major surface S1, the total thickness of the barrier material 14 may vary across the first major surface S1. Such variation may range from about 50 µm to about 100 µm.

[0069] Because the portion P1includes intermingled reinforcement material 16 and barrier material 14, the portion P1 may be referred to as a composite reinforcement material.

[0070] One aspect of a method to generate the heat control member 10A shown in Fig.1A includes applying a barrier material precursor onto first major surface S1of a reinforcement material 16; curing the barrier material precursor to form a barrier material 14, thereby generating a composite reinforcement material (e.g., at portion P1); and forming an aerogel framework 18 at a second major surface S2of the reinforcement material 16.

[0071] In an aspect, the barrier material precursor is a dispersion of the barrier material 14. In some aspects, the barrier material 14 is dispersed in an aqueous liquid binder. Any of the compositions described hereinabove (e.g., water, sodium silicate) and their analogs (potassium silicate) for forming the barrier material 14 may be used as the barrier material precursor. Within any aqueous dispersion (i.e., barrier material precursor), the water can make up from about 20 wt% to about 60 wt% of the total weight of the dispersion and the barrier material 14 can make up from about 50 wt% to about 95 wt% of the total weight of the dispersion. In one dispersion, the water content can vary between (e.g., 30 wt% to 50 wt%) and the barrier material 14 includes aluminosilicate fibers (40 wt% to 60 wt%), silicon dioxide fibers or particles (10 wt% to 20 wt%), and titanium dioxide fibers or particles (< 1 wt%). In another aspect, the aqueous liquid binder may contain monoaluminum phosphate, silicon dioxide, and a silicate solution. The viscosity of the dispersion may range from about 100 centiPoise (cP) to about 20,000 cP.AAI-105-B-PCT (1207-WO01)

[0072] In other aspects of a fabrication method described herein, a non- aqueous dispersion that includes the barrier material 14 and a non-aqueous liquid binder (e.g., a polymer, a “ceramifiable” polymer) may be used instead of the aqueous precursors described above. In some aspects, a non-aqueous dispersion may be used to form a separate layer in addition to the barrier material 14 or be used in conjunction with the barrier material 14. The non-aqueous dispersion may include any of the barrier material(s) 14 described herein. The non-aqueous dispersion may be applied to a surface, whether a major surface of a reinforcement material 16, a major surface of a heat control member 10A, an exposed surface of a previously formed layer of the barrier material 14 or a separate structure that is configured to be joined to any of the foregoing surfaces or layers. Illustrations of these other structures include a support structure 15 described below in the context of Fig.1B. Upon curing, in some aspects the non-aqueous dispersion may form a continuous layer within which the barrier material 14 is disposed. In other aspects, as described elsewhere herein, a non-aqueous dispersion may be used with a barrier material consistent with other aspects of direct application on a major surface of a reinforcement material. In other aspect, a non-aqueous dispersion may include a precursor material (e.g., as a liquid binder) that changes phase when exposed to heat. In one aspect, a phase change material may include a material that remains in a polymeric form and converts to a ceramic layer upon exposure to temperatures experienced during thermal runaway. One aspect of a “ceramifiable” polymer is polysilazane. This aspect and associated heat control member configurations are described below in more detail.

[0073] The dispersion (for both aqueous and non-aqueous dispersions) may be applied using any suitable wet deposition technique. Suitable wet deposition techniques include painting, foam rolling, spray coating (e.g., ultrasonic spray coating), dip coating (where the first major surface S1 is dipped in a manner that does not submerge the reinforcement material 16), doctor blade coating, puddle dispensing, aerosol printing, screen printing, or the like. In still another aspect, the dispersion is painted on the first major surface S1.AAI-105-B-PCT (1207-WO01)

[0074] The amount of the dispersion that is applied enables the dispersion to partially penetrate into the reinforcement material 16.

[0075] Once the dispersion is applied, the dispersion is cured. Curing may be performed by exposing the coated reinforcement material 16 to a predetermined temperature (e.g., ranging from about 25°C to about 426°C) for a predetermined time (e.g., from about 2 hours to about 24 hours). In one aspect, curing is performed by heating the coated reinforcement material 16 to a temperature of about 93°C for about 2 hours. During curing, the water (or other solvent) evaporates and a chemical reaction takes place that causes hardening of the remaining matrix. During curing, the barrier material 14 becomes immobilized within the matrix. The barrier material 14 adheres to each other and to the fibers of the reinforcement material 16 in the portion P1and at the first major surface S1. When the barrier material precursor includes aluminosilicate fibers / particles in aqueous amorphous silicon dioxide (e.g., sodium silicate) binder with a small amount of titanium dioxide, curing involves evaporation of water, formation of a silica network, and encapsulation of both alumina silicate particles and the fibers of the reinforcement material 16. Curing generates a composite reinforcement material, which is located at the portion P1 and includes the barrier material 14 attached to fibers of the reinforcement material 16.

[0076] After the composite reinforcement material is formed, the method includes forming the aerogel framework 18 in contact with the second major surface S2.

[0077] In one aspect, production of the aerogel framework 18 generally includes: i) formation of a sol-gel solution; ii) formation of a gel from the sol-gel solution; and iii) extracting the solvent from the gel materials through innovative processing and extraction, to obtain a dried aerogel material. This process is discussed below in greater detail, specifically in the context of forming inorganic aerogels, such as silica aerogels. However, the specific aspects and illustrations provided herein are not intended to limit the present disclosure to any specific type of aerogel and / or method of preparation. The present disclosure can include any aerogel formed by any associated method of preparation known to those in the art.AAI-105-B-PCT (1207-WO01)

[0078] The first step in forming an inorganic aerogel is generally the formation of a sol-gel solution through hydrolysis and condensation of metal alkoxide precursors in an alcohol-based solvent. Major variables in the formation of inorganic aerogels include the type of alkoxide precursors included in the sol-gel solution, the nature of the solvent, the processing temperature and pH of the sol-gel solution (which may be altered by addition of an acid or a base), and precursor / solvent / water ratio within the sol-gel solution. Control of these variables in forming a sol-gel solution can permit control of the growth and aggregation of the gel framework during the subsequent transition of the gel material from the “sol” state to the “gel” state. While properties of the resulting aerogels are affected by the pH of the precursor solution and the molar ratio of the reactants, any pH and any molar ratios that permit the formation of gels may be used in the present disclosure.

[0079] A sol-gel solution is formed by combining at least one gelling precursor with a solvent. Suitable solvents for use in forming a sol-gel solution include lower alcohols with 1 to 6 carbon atoms, preferably 2 to 4, although other solvents can be used as known to those with skill in the art. Examples of useful solvents include: methanol, ethanol, isopropanol, ethyl acetate, ethyl acetoacetate, acetone, dichloromethane, tetrahydrofuran, and the like. Multiple solvents can also be combined to achieve a desired level of dispersion or to optimize properties of the gel material. Selection of suitable solvents for the sol-gel and gel formation steps thus depends on the specific precursors, fillers and additives being incorporated into the sol-gel solution; as well as the target processing conditions for gelling and liquid phase extraction, and the desired properties of the final aerogel materials.

[0080] Water can also be present in the precursor-solvent solution. The water acts to hydrolyze the metal alkoxide precursors into metal hydroxide precursors. The hydrolysis reaction can be (using TEOS in ethanol solvent as an example): Si(OC2H5)4 + 4H2O → Si(OH)4 + 4(C2H5OH). The resulting hydrolyzed metal hydroxide precursors remain suspended in the solvent solution in a “sol” state, either as individual molecules or as small polymerized (or oligomerized) colloidal clusters of molecules. For example, polymerization / condensation of the Si(OH)4 precursors can occur as follows:AAI-105-B-PCT (1207-WO01) 2 Si(OH)4= (OH)3Si-O-Si(OH)3+ H2O. This polymerization can continue until colloidal clusters of polymerized (or oligomerized) SiO2(silica) molecules are formed.

[0081] Acids and bases can be incorporated into the sol-gel solution to control the pH of the solution, and to catalyze the hydrolysis and condensation reactions of the precursor materials. While any acid may be used to catalyze precursor reactions and to obtain a lower pH solution, desirable acids include: HCl, H2SO4, H3PO4, oxalic acid, and acetic acid. Any base may likewise be used to catalyze precursor reactions and to obtain a higher pH solution, with a preferable base comprising NH4OH.

[0082] The sol-gel solution can include additional co-gelling precursors, as well as filler materials and other additives. Filler materials and other additives (e.g., iron oxide, silicon carbide, etc.) may be dispensed in the sol-gel solution at any point before or during the formation of a gel. In an aspect, the sol-gel solution includes the gelling precursors, solvents, catalysts, water, filler materials and other additives, and is a homogenous solution which is capable of effective gel formation under suitable conditions.

[0083] Once the desired sol-gel solution has been formed, the sol-gel solution is cast onto the second major surface S2 or impregnated into the portion P2 at the second major surface S2. The amount of the sol-gel solution that is used will depend upon the thickness T and the desired thickness of the portion P2. In one aspect, the sol-gel solution penetrates into the reinforcement material 16 and contacts the barrier material 14. In other words, the sol-gel solution and the barrier material 14 together fill the entire thickness of the reinforcement material 16.

[0084] The gel-forming components in the sol-gel solution can be transitioned into a gel material. The process of transitioning gel-forming components into a gel material includes an initial gel formation step wherein the gel solidifies up to the gel point of the gel material. The gel point of a gel material may be viewed as the point where the gelling solution exhibits resistance to flow and / or forms a substantially continuous polymeric framework throughout its volume. A range of gel-forming techniques are known to those in the art. Examples include: maintaining the mixture in a quiescent state for a sufficient period of time; adjusting the pH of the solution;AAI-105-B-PCT (1207-WO01) adjusting the temperature of the solution; directing a form of energy onto the mixture (ultraviolet, visible, infrared, microwave, ultrasound, particle radiation, electromagnetic); or a combination thereof. When heating and / or energy is used, the type of reinforcement material 16 that is used should be considered so that the temperature does not deleteriously affect the reinforcement material 16.

[0085] The process of transitioning gel-forming components into a gel material can also include an aging step (also referred to as curing) prior to liquid phase extraction. Aging a gel material after it reaches its gel point can further strengthen the gel framework by increasing the number of cross-linkages within the network. The duration of gel aging can be adjusted to control various properties within the resulting aerogel material. This aging procedure can be useful in preventing potential volume loss and shrinkage during liquid phase extraction. Aging can involve: maintaining the gel (prior to extraction) at a quiescent state for an extended period; maintaining the gel at elevated temperatures; adding cross-linkage promoting compounds; or any combination thereof. Suitable temperatures for aging are usually between about 10°C and about 100°C. When aging is used, the type of reinforcement material 16 that is used should be considered so that the temperature does not deleteriously affect the reinforcement material 16. The aging of a gel material typically continues up to the liquid phase extraction of the wet-gel material.

[0086] The time period for transitioning gel-forming materials into a gel material includes both the duration of the initial gel formation (from initiation of gelation up to the gel point), as well as the duration of any subsequent curing and aging of the gel material prior to liquid phase extraction (from the gel point up to the initiation of liquid phase extraction). The total time period for transitioning gel-forming materials into a gel material is typically between about 1 minute and several days, preferably about 30 hours or less, about 24 hours or less, about 15 hours or less, about 10 hours or less, about 6 hours or less, about 4 hours or less, about 2 hours or less, about 1 hour or less, about 30 minutes or less, or about 15 minutes or less.

[0087] The resulting gel material (in the portion P2) may be washed in a suitable secondary solvent to replace the primary reaction solvent present in the wet-gel. SuchAAI-105-B-PCT (1207-WO01) secondary solvents may be linear monohydric alcohols with 1 or more aliphatic carbon atoms, dihydric alcohols with 2 or more carbon atoms, branched alcohols, cyclic alcohols, alicyclic alcohols, aromatic alcohols, polyhydric alcohols, ethers, ketones, cyclic ethers or their derivative.

[0088] Once the gel material has been formed and processed, the liquid phase of the gel can then be at least partially extracted from the wet-gel using extraction methods, including innovative processing and extraction techniques, to form the aerogel framework 18. Liquid phase extraction, among other factors, plays an important role in engineering the characteristics of aerogels, such as porosity and density, as well as related properties such as thermal conductivity. Generally, aerogels are obtained when a liquid phase is extracted from a gel in a manner that causes low shrinkage to the porous network and framework of the wet gel.

[0089] Aerogels are commonly formed by removing the liquid mobile phase from the gel material at a temperature and pressure near or above the critical point of the liquid mobile phase. Once the critical point is reached (near critical) or surpassed (supercritical) (i.e., pressure and temperature of the system is at or higher than the critical pressure and critical temperature respectively) a new supercritical phase appears in the fluid that is distinct from the liquid or vapor phase. The solvent can then be removed without introducing a liquid-vapor interface, capillary pressure, or any associated mass transfer limitations typically associated with liquid-vapor boundaries. Additionally, the supercritical phase is more miscible with organic solvents in general, thus having the capacity for better extraction. Co-solvents and solvent exchanges are also commonly used to optimize the supercritical fluid drying process.

[0090] If evaporation or extraction occurs below the supercritical point, capillary forces generated by liquid evaporation can cause shrinkage and pore collapse within the gel material. Maintaining the mobile phase near or above the critical pressure and temperature during the solvent extraction process reduces the negative effects of such capillary forces. In certain examples of the present disclosure, the use of near-critical conditions just below the critical point of the solvent system may allow production ofAAI-105-B-PCT (1207-WO01) aerogel materials or compositions with sufficiently low shrinkage, thus producing a commercially viable end-product.

[0091] Several additional aerogel extraction techniques are known in the art, including a range of different approaches in the use of supercritical fluids in drying aerogels. For example, Kistler (J. Phys. Chem. (1932) 36: 52-64) describes a simple supercritical extraction process where the gel solvent is maintained above its critical pressure and temperature, thereby reducing evaporative capillary forces and maintaining the structural integrity of the gel network. U.S. Patent No.4,610,863 describes an extraction process where the gel solvent is exchanged with liquid carbon dioxide and subsequently extracted at conditions where carbon dioxide is in a supercritical state. U.S. Patent No.6,670,402 teaches extracting a liquid phase from a gel via rapid solvent exchange by injecting supercritical (rather than liquid) carbon dioxide into an extractor that has been pre-heated and pre-pressurized to substantially supercritical conditions or above, thereby producing aerogels. U.S. Patent No. 5,962,539 describes a process for obtaining an aerogel from a polymeric material that is in the form a sol-gel in an organic solvent, by exchanging the organic solvent for a fluid having a critical temperature below a temperature of polymer decomposition, and supercritically extracting the fluid / sol-gel. U.S. Patent No.6,315,971 discloses a process for producing gel compositions comprising: drying a wet gel comprising gel solids and a drying agent to remove the drying agent under drying conditions sufficient to reduce shrinkage of the gel during drying. U.S. Patent No.5,420,168 describes a process whereby resorcinol / formaldehyde aerogels can be manufactured using a simple air drying procedure. U.S. Patent No.5,565,142 describes drying techniques in which the gel surface is modified to be stronger and more hydrophobic, such that the gel framework and pores can resist collapse during ambient drying or subcritical extraction. Other examples of extracting a liquid phase from aerogel materials can be found in U.S. Patent Nos.5,275,796 and 5,395,805.

[0092] One example of extracting a liquid phase from the wet-gel uses supercritical conditions of carbon dioxide, including, for example: first substantially exchanging the primary solvent (e.g., the solvent used in the sol-gel solution) presentAAI-105-B-PCT (1207-WO01) in the pore network of the gel (within the portion P2) with liquid carbon dioxide; and then heating the wet gel (within the portion P2) (typically in an autoclave) beyond the critical temperature of carbon dioxide (about 31.06°C) and increasing the pressure of the system to a pressure greater than the critical pressure of carbon dioxide (about 1070 psig). The pressure around the gel material can be slightly fluctuated to facilitate removal of the supercritical carbon dioxide fluid from the gel. Carbon dioxide can be recirculated through the extraction system to facilitate the continual removal of the primary solvent from the wet gel. Finally, the temperature and pressure are slowly returned to ambient conditions to produce a dry aerogel material. Carbon dioxide can also be pre-processed into a supercritical state prior to being injected into an extraction chamber.

[0093] One aspect of an alternative method of forming the aerogel framework 18 includes the acidification of basic metal oxide precursors (such as sodium silicate) in water to make a hydrogel. The hydrogel is cast onto the second major surface S2. Salt by-products may be removed from the silicic acid precursor by ion-exchange and / or by washing subsequently formed gels with water. Removing the water from the pores of the gel can be performed via exchange with a polar organic solvent such as ethanol, methanol, or acetone. The liquid phase in the gel is then at least partially extracted using innovative processing and extraction techniques.

[0094] Another aspect of an alternative method of forming the aerogel framework 18 includes reducing the damaging capillary pressure forces at the solvent / pore interface by chemical modification of the matrix materials in their wet gel state (after being cast onto the second major surface S2) via conversion of surface hydroxyl groups to hydrophobic trimethylsilylethers, thereby allowing for liquid phase extraction from the gel materials at temperatures and pressures below the critical point of the solvent.

[0095] Large-scale production of aerogel materials or compositions can be complicated by difficulties related to the continuous formation of gel materials on a large scale; as well as the difficulties related to liquid phase extraction from gel materials in large volumes using innovative processing and extraction techniques. TheAAI-105-B-PCT (1207-WO01) formation of the aerogel framework 18 is accommodating to production on a large scale. In certain aspects, gel materials of the present disclosure can be produced in large scale through a continuous casting and gelation process. In certain aspects, the aerogel framework 18 is produced in a large scale which requires the use of large scale extraction vessels. Large scale extraction vessels of the present disclosure can include extraction vessels which have a volume of about 0.1 m3or more, about 0.25 m3or more, about 0.5 m3or more, or about 0.75 m3or more.

[0096] In other aspects, extracting a liquid phase from the wet-gel may be accomplished in an ambient atmosphere (e.g., air) and at ambient temperatures (e.g., from 20oC to 35oC). This process may be a convenient option if the wet gel and reinforcement are composed so that shrinkage and / or pore collapse are at a low enough level such that the thermal conductivity of the dried gel is not lower than 100 milli Watts / m-K.

[0097] The dry aerogel framework 18 can be further processed to enhance target properties of the aerogel framework 18. In certain aspects, dried aerogel compositions can be subjected to a heat treatment, such as pyrolysis, to produce a heat treated aerogel composition. When heat treatment(s) is / are used, the type of reinforcement material 16 that is used should be considered so that the temperature does not deleteriously affect the reinforcement material 16. Carefully controlled heat treatment can be used to reduce or stabilize the hydrocarbon fuel content of the aerogel framework 18, which can improve corresponding HOC and Tdproperties of the aerogel framework 18. In certain aspects, the heat treatment of a dried aerogel framework 18 can take place under a range of temperatures, pressures, durations, and atmospheric conditions.

[0098] In certain aspects of the present disclosure, the dried aerogel framework 18, and thus the entire heat control member 10A, can be subjected to a treatment temperature ranging from 200°C to less than 800°C.

[0099] In certain aspects of the present disclosure, the dried aerogel framework 18, and thus the entire heat control member 10A, can be subjected to a heat treatment for a duration of time of 3 hours or more, between 10 seconds and 3 hours, betweenAAI-105-B-PCT (1207-WO01) 10 seconds and 2 hours, between 10 seconds and 1 hour, between 10 seconds and 45 minutes, between 10 seconds and 30 minutes, between 10 seconds and 15 minutes, between 10 seconds and 5 minutes, between 10 seconds and 1 minute, between 1 minute and 3 hours, between 1 minute and 1 hour, between 1 minute and 45 minutes, between 1 minute and 30 minutes, between 1 minute and 15 minutes, between 1 minute and 5 minutes, between 10 minutes and 3 hours, between 10 minutes and 1 hour, between 10 minutes and 45 minutes, between 10 minutes and 30 minutes, between 10 minutes and 15 minutes, between 30 minutes and 3 hours, between 30 minutes and 1 hour, between 30 minutes and 45 minutes, between 45 minutes and 3 hours, between 45 minutes and 90 minutes, between 45 minutes and 60 minutes, between 1 hour and 3 hours, between 1 hour and 2 hours, or between 1 hour and 90 minutes.

[0100] In certain aspects of the present disclosure, the dried aerogel framework 18, and thus the entire heat control member 10A, can be subjected to a treatment temperature between 200°C and 750°C for a duration of time between 10 seconds and 3 hours.

[0101] The heat treatment of the dried aerogel framework 18, and thus the entire heat control member 10A, can take place in a reduced oxygen environment. Within the context of the present disclosure, the term “reduced oxygen environment” refers to an atmosphere which comprises a concentration by volume of 10 vol% oxygen or less (which is below the amount of oxygen in ambient air at standard conditions). A reduced oxygen environment can comprise positive pressurized atmospheres which have elevated concentrations of inert gases, including (but not limited to) nitrogen, argon, helium, neon, argon, and xenon. A reduced oxygen environment can also include vacuum atmospheres which have reduced concentrations of oxygen, including vacuums and partial vacuums. A reduced oxygen environment can further include atmospheres contained in a sealed container in which limited combustion has consumed a portion of the oxygen content in the sealed atmosphere. A reduced oxygen environment can include 10 vol% oxygen or less, 8 vol% oxygen or less, 6 vol% oxygen or less, 5 vol% oxygen or less, 4 vol% oxygen orAAI-105-B-PCT (1207-WO01) less, 3 vol% oxygen or less, 2 vol% oxygen or less, or 1 vol% oxygen or less. A reduced oxygen environment can include between 0.1 to 10 vol% oxygen, between 0.1 to 5 vol% oxygen, between 0.1 to 3 vol% oxygen, between 0.1 to 2 vol% oxygen, or between 0.1 to 1 vol% oxygen. In certain aspects, the aerogel framework 18, and thus the entire heat control member 10A, is heat treated in a reduced oxygen atmosphere comprising between about 85% to about 99.9% inert gas (such as nitrogen). In one specific aspect of the present disclosure, the aerogel framework 18, and thus the entire heat control member 10A, is heat treated in a reduced oxygen atmosphere comprising between about 95% to about 99.9% inert gas (such as nitrogen) at a temperature between about 200°C and about 700°C for a duration of time between about 1 minute and about 3 hours.

[0102] The heat treatment of the dried aerogel framework 18, and thus the entire heat control member 10A, can alternatively take place in an ambient atmospheric (i.e., air) environment. Ambient atmosphere heat treatment may expose the dried aerogel framework 18, and thus the entire heat control member 10A, to a treatment temperature between 250°C and 450°C for a duration of time between 1 minute and 1 hour. In some aspects, ambient atmosphere heat treatment may expose the dried aerogel framework 18, and thus the entire heat control member 10A, to a treatment temperature between 250°C and 450°C for a duration of time between 4 minutes and 10 minutes.

[0103] While the method described herein identifies desirable points at which the sol-gel solution can be introduced to the second major surface S2, it is to be understood that the second major surface S2 of the reinforcement material 16 can be exposed to the gel at any point in the gelling process to produce a wet, fibrous gel composition. The wet gel composition may then be dried to produce the aerogel framework 18 within the portion P2.

[0104] The aerogel framework 18 can also include an opacifier to reduce the radiative component of heat transfer. At any point prior to gel formation, opacifying compounds or precursors thereof may be dispersed into the sol-gel solution. Examples of opacifying compounds include: Boron Carbide [B4C], Diatomite,AAI-105-B-PCT (1207-WO01) Manganese ferrite, MnO, NiO, SnO, Ag2O, Bi2O3, carbon black, titanium oxide, iron titanium oxide, aluminum oxide, zirconium silicate, zirconium oxide, iron (II) oxide, iron (III) oxide, manganese dioxide, iron titanium oxide (ilmenite), chromium oxide, carbides (such as SiC, TiC or WC), or mixtures thereof. Examples of opacifying compound precursors include, but are not limited to: TiOSO4or TiOCl2.

[0105] In addition to the heat control member 10A, shown in Fig.1A, other configurations and variations of heat control members are described below in Fig.1B, Fig.1C, Fig.2A, and Fig.2B. The description of some elements of these structures analogous to the elements described above in the context of Fig.1A are applicable to these configurations.

[0106] Fig.1B illustrates a configuration in which a barrier material 14 is deposited on a support structure 15 to form a free standing barrier 17. This is in contrast to the heat control member 10A shown in Fig.1A in which the barrier material 14 is described as being applied directly on the reinforcement material 16 to form the heat control member 10A.

[0107] As shown in Fig.1B, the heat control member 10A’ includes a thermal insulation layer 12, a free standing barrier 17, and, in some aspects, an encapsulation layer 21. The free standing barrier 17 includes the support structure 15 and a barrier material layer 19 formed from the barrier material 14.

[0108] The thermal insulation layer 12 description presented in the context of Fig.1A is applicable to the configuration shown in Fig.1B, with an exception. In some aspects of Fig.1A, the first portion P1and the second portion P2are regions of respective incorporation of the barrier material 14 and the aerogel framework 18 within the reinforcement material 16. The portions P1and P2may result from infusion or penetration of their liquid precursors through the first major surface S1and the second major surface S2. In the example of Fig.1B, in which the barrier layer 19 is formed on the support structure 15 that is independent from the reinforcement material 16, there is not any infusion of liquid precursors of the barrier material 4 into the reinforcement material 16, and thus no first portion P1. Aerogel precursors may be separately infused throughout a thickness T of the reinforcement material 16 at any depth.AAI-105-B-PCT (1207-WO01) Because aerogel precursor infusion may be any depth within the reinforcement material 16, P2has been omitted from Fig.1B for clarity.

[0109] The free standing barrier 17 may be formed by applying a dispersion of the barrier material 14 onto the support structure 15 instead of applying the dispersion directly to an exposed surface of the thermal insulation layer 12 or reinforcement material 16. The phrase “free standing” refers to the ability of support structure 15 to support its own weight and remain in a planar configuration under its own weight even after application of the barrier material 14 to the support structure 15. Dispersions of the barrier material 14 may include any of the aqueous and non-aqueous dispersions of barrier materials 14 described herein. In some aspects, a dispersion may be any of the following barrier materials: kaolin, hallyosite, mica, other alumino-silicate clays, silicon carbide (SiC), silicon nitride (SiN), alumina (Al2O3), zirconia (Zr2O3), titania (TiO2), boron nitride (BN), carbon black, aluminum silicide (Al-Si), among others described herein. Regardless of the barrier material 14 used, the barrier material 14 applied to the support structure 15 will remain on the support structure as the layer 19 after curing.

[0110] In some aspects, a liquid binder component of the dispersion used to apply the barrier material 14 to the support structure 15 functions, post-curing, primarily as a continuous layer in which the barrier material is suspended / immobilized. Sodium silicate in water and potassium silicate in water, as described above, are examples of an aqueous precursor that, after curing, maintains the physical distribution of the barrier material 14 throughout the layer 19.

[0111] In other aspects, the precursor component of the dispersion may include a reactive component that, after curing, may have additional functions and thereby become an added layer of thermal protection during a thermal runaway event. In one aspect, a reactive precursor component that may be used in the dispersion is the “ceramifiable” polymer polysilazane. The reactive precursor component may be used instead of the binder material 14 or along with the binder material 14.

[0112] Polysilazane, whether present in the support structure 15 or as a direct coating layer on the thermal insulation layer 12 (as shown in Fig.1A), may beAAI-105-B-PCT (1207-WO01) converted to a ceramic material when exposed to the heat of a thermal runaway event. In this way, polysilazane may absorb energy from the thermal runaway event as a result of its phase transformation from a polymer layer to a ceramic layer. Upon phase transformation to a ceramic layer, the ceramified polysilazane layer forms a continuous ceramic layer that protects the underlying thermal insulation layer 12 from high heat, flame, and the impingement of thermal runaway ejecta. This protection, in turn, improves the ability of the thermal insulation layer 12 to prevent the ignition of one battery cell by another battery cell in runaway. Experimental Examples 5, 6, 7, and 8 include samples that illustrate use of polysilazane as a binder material with various barrier materials 14. Other polymer-based ceramifiable materials may be used as alternatives to polysilazane.

[0113] Returning to the description of the free standing barrier 17, the support structure 15 in the free standing barrier 17 may be fabricated from any material convenient for deposition of the dispersion. In some aspects, the support structure 15 may support the subsequent formation and handling (e.g., during battery pack assembly) of the free standing barrier 17. In one aspect, the support structure 15 is a metallic mesh, such as a mesh formed from steel, copper, carbon fiber, aluminum, or combinations thereof. In one aspect, the support structure 15 is fabricated from a material able to maintain its free standing configuration and dimensions when exposed to temperatures from 500oC to 1200oC (e.g., temperatures commonly present during stages of thermal runaway). This in turn, improves the ability of the free standing barrier 17 and the heat control member 10A’ as a whole to prevent the spread of a fire from one cell to another.

[0114] In one aspect, the support structure 15 may have a mesh size that is dimensioned so that the barrier material dispersion will form a continuous layer 19 on the support structure 15 after curing. That is, the mesh size of the support structure 15 is small enough so that surface tension forces of the dispersion will not cause the dispersion to de-wet from the mesh framework during curing but instead is retained within individual cells that form the mesh framework during deposition and after curing.AAI-105-B-PCT (1207-WO01)

[0115] In some aspects, the support structure 15 may have a mesh size of from 8 (i.e., 8 squares per inch or equivalently a square having a side length of 2,360 microns) to 16 (i.e., 16 squares per inch or equivalently a square having a side length of 1,200 microns). In other aspects, a given mesh size may be accommodated by the addition of thickening agents or surfactants to vary the surface energy of the barrier material dispersion so that the barrier material dispersion will form a continuous layer 19 the support structure 15.

[0116] In another aspect, the support structure 15 may be fabricated from a material that also serves as a reinforcement material 16, as described herein. In this aspect, the dispersion containing the barrier material 14 is applied to the support structure 15, which may be fabricated from a woven or non-woven fiber material, an open cell foam, or any other material described herein in the context of the reinforcement material 16.

[0117] In some aspects, the free standing barrier layer 17 may be from 100 microns to 700 microns thick.

[0118] In some aspects, the free standing barrier layer 17 may be placed on, over, or in direct or indirect contact with the hydrophobic thermal insulation layer 12. In some aspects, the free standing barrier layer 17 may be bound to the hydrophobic thermal insulation layer 12 using the encapsulation layer 21. In some aspects, the encapsulation layer 21 may include a layer of polymer film used to improve handling of the hydrophobic thermal insulation layer, provide a uniform surface on which to place product identifying information (e.g., a bar code, a lot number, a part number), and hold various layers of the heat control member together. In some aspects, the encapsulation layer 21 may be formed from a polyethylene terephthalate (PET) layer, a polyethylene (PE) layer, or other similar polymers that may be wrapped around, and conform to, the hydrophobic thermal insulation layer 12. Multiple encapsulation layers 21 may be used in a stack as well.

[0119] In some aspects, the free standing barrier layer 17 may be attached or adhered to the hydrophobic thermal insulation layer 12 using an adhesive or a physical attachment (e.g., a staple, a stitch, a wire connector, a clasp).AAI-105-B-PCT (1207-WO01)

[0120] Fig.1C illustrates a heat control member 10A’’ that is an alternative configuration to the heat control member 10A and the heat control member 10A’. The heat control member 10A’’ includes a hydrophobic thermal insulation layer 12, a barrier material 14, and a heat diffusion layer 23.

[0121] The details and aspects presented above regarding the hydrophobic thermal insulation layer 12 and the barrier material 14 are applicable to the configuration of the heat control member 10A” illustrated in Fig.1C. The presence of the heat diffusion layer 23 may alter a function of the heat control member 10A” by enabling the conduction of heat within the plane of the major surface of the heat diffusion layer 23 (parallel to the previously defined first major surface S1 of the reinforcement material 16). By enabling the conduction of heat in this plane, heat at a point of flame impingement on the heat control member 10A” may be conducted away, thereby reducing an upper limit of a temperature experienced through the thickness T of the heat control member 10A’’. Experimental Examples 5, 6, 7, and 8 include samples described below illustrate this beneficial effect.

[0122] In aspects, the heat diffusion layer 23 may be formulated from any of the barrier materials 14 described above. Barrier materials having a combination of a high enough thermal conductivity to facilitate the diffusion of heat (e.g., a thermal conductivity above 20 W / m-K or above 100 W / m-K) have been found to be more effective than those materials with thermal conductivities below those values. Barrier materials that have a high hardness (e.g., above Mohs Scale value of 8) reduce the likelihood of ablation of the heat diffusion layer (and any underlying layers protected from the flame by the heat diffusion layer) during a thermal runaway event.

[0123] Table 1 presents the thermal conductivity and hardness of various barrier materials, some of which appear in the experimental examples section. Silicon carbide was experimentally found to be a successful barrier material in part because of its high thermal conductivity and high hardness.AAI-105-B-PCT (1207-WO01) Table 1 Barrier Thermal Hardness (Mohs

[0124] Referring now to Fig.2A and Fig.2B, other aspects of the heat control member 10B, 10C are depicted.

[0125] The heat control member 10B shown in Fig.2A includes the hydrophobic thermal insulation layer 12, the barrier material 14’, and a second hydrophobic thermal insulation layer 12’, wherein the barrier material 14’ is positioned between the hydrophobic thermal insulation layer 12 and the second hydrophobic thermal insulation layer 12’.

[0126] As described in reference to Fig.1A, the hydrophobic thermal insulation layer 12 is an illustration of the reinforced aerogel composition disclosed herein because it includes the reinforcement material 16 and the aerogel framework 18. The hydrophobic thermal insulation layer 12’ is similar because it includes a reinforcement material 16’ and an aerogel framework 18’ incorporated with the reinforcement material 16’. Because this example of the heat control member 10B includes two hydrophobic thermal insulation layers 12, 12’, the respective components of these layers will be referred to as the first reinforcement material 16 and the first aerogel framework 18, and the second reinforcement material 16’ and the second aerogel framework 18’.

[0127] Any example of the reinforcement materials (e.g., open-cell foam or fiber reinforcement materials) set forth herein may be used as the reinforcement materials 16 and 16’ in the example of Fig.2A. In one example, the reinforcement materials 16AAI-105-B-PCT (1207-WO01) and 16’ are independently selected from the group consisting of a non-woven fiber batting, a glass fiber veil, a glass fiber veil including a binder, melamine foam, and aluminosilicate fibers. In one example, each of the reinforcement materials 16 and 16’ is a continuous sheet of interconnected or interlaced fibers. In another example, each of the reinforcement materials 16 and 16’ is sheet of melamine foam.

[0128] As shown in Fig.2A, the first reinforcement material 16 includes the first major surface S1, the second major surface S2, and the (first) thickness T therebetween. Similarly, the second reinforcement material 16’ includes a third major surface S3, a fourth major surface S4, and a second thickness T2 therebetween. Each of the thicknesses T, T2 may be 15 mm or less, 10 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less. In the example shown in Fig.2A, the barrier material 14’ is in contact with the first major surface S1and with the third major surface S3 and is incorporated into respective first portions P1, P’1 of each of the first thickness T and the second thickness T2. The first aerogel framework 18 is in contact with the second major surface S2and a second portion P2of the first thickness T that is greater than the first portion P1 of the first thickness T. The second aerogel framework 18’ is in contact with the fourth major surface S4 and a second portion P’2 of the second thickness T2that is greater than the first portion P’1of the second thickness T2.

[0129] As mentioned, the first aerogel framework 18 is incorporated with the first reinforcement material 16 such that first the aerogel framework 18 is in contact with the second major surface S2, and the second aerogel framework 18’ is incorporated with the second reinforcement material 16’ such that the second aerogel framework 18’ is in contact with the fourth major surface S4. As will be described in detail below, the innovative processing and extraction technique used to form the aerogel frameworks 18, 18’ is performed such that the aerogel precursors (in the form of a sol- gel solution) are cast into the reinforcement materials 16, 16’ at their respective major surfaces S2, S4. Thus, the aerogel framework 18 is formed within the portion P2 and the aerogel framework 18’ is formed within the portion P’2.

[0130] The thickness of each of the portions P2, P’2 is a fraction of the respective total thickness T, T2 and is greater than the thickness of the respectiveAAI-105-B-PCT (1207-WO01) portions P1,P’1that includes the barrier material 14’. In an example, the thickness of each of the portions P2, P’2is greater than 500 µm and is up to 5 mm (depending upon the respective thicknesses T, T2). Additionally, the depth of the penetration of the aerogel precursors may vary across the second major surface S2 and the fourth major surface S4, and thus the total thickness of the respective portions P2, P’2may vary across the second major surface S2 and the fourth major surface S4.

[0131] The aerogel frameworks 18, 18’ may be any of the examples set forth herein, including the inorganic aerogels, the organic aerogels, or the organic / inorganic hybrid aerogels. Any of these aerogels may be exposed to any of the treatment processes disclosed herein to impart or improve the hydrophobicity. Thus, in an example, the aerogel frameworks 18, 18’ are both hydrophobic. As a specific example, the aerogel frameworks 18, 18’ may each be a hydrophobic silica-based framework, such as an inorganic silica aerogel formed primarily from alcohol solutions of hydrolyzed silicate esters formed from silicon alkoxides. In one aspect, the aerogel framework 18 (e.g., inorganic aerogel) is different from the aerogel framework 18’ (e.g., organic aerogel).

[0132] Any barrier material 14 described herein may be used for the barrier material 14’.

[0133] The barrier material 14’ is in contact with the first major surface S1 of the reinforcement material 16 and with the third major surface S3 of the reinforcement material 16’. While the barrier material 14’ is shown in Fig.2A as a layer along the first major surface S1and the third major surface S3, it is to be understood that the barrier material 14’ is incorporated into a portion (shown as portion P1) of the thickness T and into a portion (shown as portion P’1) of the thickness T2. More particularly, the barrier material 14’ may coat some of the fibers at the first and third major surfaces S1, S3and may also penetrate into pores / voids / spaces between the fibers at the first and third major surfaces S1, S3 and extending into the portions P1, P’1. The thickness of each of the portion P1, P’1is a fraction of the total thickness of the barrier material 14’ that is present. While not shown in Fig.2A, the portion P1, P’1 may be thicker than a portion P’3 of the barrier material 14’ that is positioned on the first and third major surfaces S1,AAI-105-B-PCT (1207-WO01) S3(i.e., not penetrating into the thicknesses T, T2). In one example, the total thickness of the barrier material 14’ (i.e., thickness of the portion P1+ thickness of the portion P’1+ thickness of the portion P’3) ranges from about 50 microns (µm) to about 500 microns (µm). Additionally, because the first and third major surfaces S1, S3 may not be flat and because the depth of the penetration of the barrier material 14’ into the portions P1, P’1 may vary across the first and third major surface S1, S3, respectively, the total thickness of the barrier material 14’ may also vary across the first and third major surface S1, S3.

[0134] Because the portions P1, P’1 include intermingled reinforcement material 16, 16’ and barrier material 14’, the portions P1, P’1 may be referred to as composite reinforcement materials.

[0135] One example of a method to generate the heat control member 10B shown in Fig.2A includes applying a barrier material precursor onto a first major surface S1of a first reinforcement material 16 and onto a third major surface S3of a second reinforcement material 16’; placing the first and third major surfaces S1, S3, having the barrier material 14’ thereon, in contact with each other; curing the barrier material precursor to form a barrier material 14’, thereby generating a composite reinforcement material (e.g., at portions P1and P’1); and respectively forming aerogel frameworks 18, 18’ at a second major surface S2 of the reinforcement material 16 and at a fourth major surface S4 of the reinforcement material 16’.

[0136] Similar to the method used to form the heat control member 10A, this example method uses an aqueous dispersion of the barrier material 14’ as the barrier material precursor. Any of the compositions described herein for forming the barrier materials 14 may be used in this example method.

[0137] The dispersion may be applied to each of the major surfaces S1, S3, using any suitable wet deposition technique, such as, painting, foam rolling, spray coating (e.g., ultrasonic spray coating), dip coating (where the first major surface S1 is dipped in a manner that does not submerge the reinforcement material 16), doctor blade coating, puddle dispensing, aerosol printing, screen printing, or the like.AAI-105-B-PCT (1207-WO01)

[0138] The amount of the dispersion that is applied to each major surface S1, S3enables the dispersion to partially penetrate into the reinforcement materials 16, 16’.

[0139] Once the dispersion is applied to each of the major surfaces S1, S3, the major surfaces S1, S3 are placed into contact with each other. The dispersion is then cured. Curing may be performed by exposing the coated reinforcement materials 16, 16’ that are in contact with each other to a predetermined temperature for a predetermined time. In one example, curing is performed by heating the coated reinforcement materials 16, 16’ to a temperature of about 93°C for about 2 hours. During curing, the water evaporates and a chemical reaction takes place that causes hardening of the remaining matrix. During curing, the barrier material 14’ becomes immobilized within the matrix. The barrier material 14’ adheres to the fibers of the reinforcement material 16 in the portion P1and at the first major surface S1and to the reinforcement material 16’ in the portion P’1 and at the third major surface S3. Curing generates a composite reinforcement material, which is located at each portion P1, P’1and includes the barrier material 14’ attached to fibers of the reinforcement materials 16, 16’.

[0140] After the composite reinforcement material is formed at each portion P1, P’1, the method includes sequentially forming the aerogel frameworks 18, 18’. The aerogel frameworks 18, 18’ may be formed via any of the method described herein using any example of the sol-gel solution described herein for the aerogel framework 18 of Fig.1A, as long as the processes are performed sequentially so that one of the frameworks 18 is formed in contact with the second major surface S2and the other of the frameworks is performed in contact with the fourth major surface S4.

[0141] In a variation, the heat control member 10B may further include a free standing barrier layer 17 and / or a heat diffusion layer 23, such as those described above in the context of Fig.1B and / or Fig.1C. For example, alternative configurations of the heat control member 10B may include the heat diffusion layer 23 on the major surface S2, the major surface S4, between the major surface S3and the barrier material 14’, between the major surface S1 and the barrier material 14’, and any combination thereof.AAI-105-B-PCT (1207-WO01)

[0142] Variations of the heat control member 10B are illustrated in Fig.2A’, Fig. 2A’’, Fig.2A’’’. Fig.2A’ illustrates a heat diffusion layer 23 in contact with a major surface S4 of second aerogel framework 18’. Fig.2A’’ illustrates a barrier material 14’ between two heat diffusion layers 23A and 23B. Fig.2A’’’ illustrates a free standing barrier layer 17 on the major surface S2. As will be appreciated, the aerogel framework 18 may extend beyond the region P2 throughout the entire thickness T of the reinforcement material 16 when using a free standing barrier. Any combination of these layers at any of the major surfaces S1, S2, S3, and / or S4may be accomplished based upon the description herein.

[0143] Similar to the heat control member 10B shown in Fig.2A, the heat control member 10C shown in Fig.2B includes a hydrophobic thermal insulation layer 12A, a barrier material 14’’, and a second hydrophobic thermal insulation layer 12B, wherein the barrier material 14’’ is positioned between the hydrophobic thermal insulation layer 12A and the second hydrophobic thermal insulation layer 12B. However, unlike the heat control member 10B shown in Fig.2A (which includes the aerogel framework 18, 18’ at the major surfaces S2, S4), the heat control member 10C shown in Fig.2B includes respective aerogel frameworks 18A, 18B throughout the thicknesses TA, TBof the respective reinforcement materials 16A, 16B. In one aspect, at least one of the aerogel frameworks 18A, 18B contacts the barrier material 14’’. In another aspect, both of the aerogel frameworks 18A, 18B contact the barrier material 14’’.

[0144] In a variation, the heat control member 10C may further include a heat diffusion layer 23, such as that described above in the context of Fig.1B and / or Fig. 1C. For example, alternative configurations of the heat control member 10C may include the heat diffusion layer 23 on the major surface S2A, the major surface S4B, between the major surface S3B and the barrier material 14”, between the major surface S1A and the barrier material 14”, and any combination thereof.

[0145] The hydrophobic thermal insulation layers 12A, 12B are also examples of the reinforced aerogel composition disclosed herein because they include reinforcement materials 16A, 16B and aerogel frameworks 18A, 18B. Because thisAAI-105-B-PCT (1207-WO01) example of the heat control member 10C includes two hydrophobic thermal insulation layers 12A, 12B, the respective components of these layers will be referred to as the first reinforcement material 16A and the first aerogel framework 18A, and the second reinforcement material 16B and the second aerogel framework 18B.

[0146] Any example of the reinforcement materials (e.g., open-cell foam or fiber reinforcement materials) set forth herein may be used as the reinforcement materials 16A and 16B in the example of Fig.2B. In one example, the reinforcement materials 16A and 16B are independently selected from the group consisting of a non-woven fiber batting, a glass fiber veil, a glass fiber veil including a binder, melamine foam, and aluminosilicate fibers. In one example, each of the reinforcement materials 16A and 16B is a continuous sheet of interconnected or interlaced fibers. In another example, each of the reinforcement materials 16A and 16B is sheet of melamine foam.

[0147] As shown in Fig.2B, the first reinforcement material 16A includes a first major surface S1A, a second major surface S2A, and a (first) thickness TAtherebetween. Similarly, the second reinforcement material 16B includes a third major surface S3B, a fourth major surface S4B, and a second thickness T2B therebetween. Each of the thicknesses TA, TB may be 15 mm or less, 10 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less.

[0148] In the example shown in Fig.2B, the barrier material 14’’ is in contact with the first major surface S1A and with the third major surface S3B. As will be described below, in this example, the aerogel frameworks 18A, 18B are formed in the reinforcement materials 16A, 16B prior to the addition of the barrier material 14’’, and thus the barrier material 14’’ does not penetrate into the reinforcement materials 16A, 16B at the respective surfaces S1A, S3B. As such, the contact between the barrier material 14’’ and the reinforcement materials 16A, 16B is at the respective surfaces S1A, S3B.

[0149] Also in the example shown in Fig.2B, the first aerogel framework 18A is located throughout the thickness first thickness TA. Similarly, the second aerogel framework 18B is located throughout the thickness first thickness TB. In one aspect, at least one of the first aerogel framework 18A and the second aerogel framework 18BAAI-105-B-PCT (1207-WO01) contacts the barrier material 14’’. In one aspect, both of the first aerogel framework 18A and the second aerogel framework 18B contact the barrier material 14’’.

[0150] The aerogel frameworks 18A, 18B may be any of the examples set forth herein, including the inorganic aerogels, the organic aerogels, or the organic / inorganic hybrid aerogels. Any of these aerogels may be exposed to any of the treatment processes disclosed herein to impart or improve the hydrophobicity. Thus, in an example, the aerogel frameworks 18A, 18B are both hydrophobic. As a specific example, the aerogel frameworks 18A, 18B may each be a hydrophobic silica-based framework, such as an inorganic silica aerogel formed primarily from alcohol solutions of hydrolyzed silicate esters formed from silicon alkoxides.

[0151] Any barrier material 14 described herein may be used for the barrier material 14’’. The thickness of the barrier material 14 ranges from about 50 microns (µm) to about 500 microns (µm). Additionally, because the first and third major surfaces S1A, S3Bmay not be flat, the total thickness of the barrier material 14’’ may also vary across the first and third major surface S1A, S3B.

[0152] One example of a method to generate the heat control member 10C shown in Fig.2B includes applying a barrier material precursor onto a surface S1A, S3B of each of a first hydrophobic thermal insulation layer 18A and a second hydrophobic thermal insulation layer 18B, placing the surfaces S1A, S3B of the first hydrophobic thermal insulation layer 18A and the second hydrophobic thermal insulation layer 18B into contact with one another; and curing the barrier material precursor to form a barrier material 14’’. In another example, the barrier material precursor is applied onto one surface S1A or S3B and the other surface S3B or S1A is placed into contact with the applied barrier material precursor.

[0153] Prior to performing this method, each of the hydrophobic thermal insulation layers 12A, 12B may be formed. To form the hydrophobic thermal insulation layers 12A, 12B (i.e., the aerogel frameworks 18A, 18B within the respective reinforcement materials 16A, 16B), any example of the sol-gel solution disclosed herein is generated. Once the desired sol-gel solution has been formed, the sol-gel solution is cast onto impregnated into each of the reinforcement materials 16A, 16B,AAI-105-B-PCT (1207-WO01) either simultaneously or sequentially. The gel-forming components in the sol-gel solution can be transitioned into a gel material and processed as described herein. Then, the liquid phase of the gels can then be at least partially extracted from the wet- gel using extraction methods, including innovative processing and extraction techniques, to form the respective aerogel frameworks 18A, 18B throughout the thickness TA, TB of the reinforcement materials 16A, 16B.

[0154] Similar to the methods used to form the heat control members 10A, 10B, this example method uses a dispersion of the barrier material 14’’ as the barrier material precursor. Any of the compositions described herein to form the barrier materials 14 may be used.

[0155] The dispersion may be applied to each of the major surfaces S1A, S3B, using any suitable wet deposition technique, such as painting, foam rolling, spray coating (e.g., ultrasonic spray coating), dip coating (where the first major surface S1 is dipped in a manner that does not submerge the reinforcement material 16), doctor blade coating, puddle dispensing, aerosol printing, screen printing, or the like.

[0156] Once the dispersion is applied to each of the major surfaces S1A, S3B, the major surfaces S1A, S3B are placed into contact with each other. The dispersion is then cured. Curing may be performed by exposing the coated reinforcement materials 16A, 16B that are in contact with each other to a predetermined temperature for a predetermined time. In one example, curing is performed by heating the coated reinforcement materials 16A, 16B to a temperature of about 93°C for about 2 hours. During curing, the water evaporates and a matrix is formed such that the barrier material 14’’ is physically contained between the hydrophobic thermal insulation layers 12A, 12B. Penetration of the barrier material 14’’ into the thicknesses TA, TBof the hydrophobic thermal insulation layers 12A, 12B is unlikely due to the hydrophobic nature of the layers 12A, 12B. However, some chemical attachment may take place between the barrier material 14’’ and fibers at the surfaces S1A, S3B of the reinforcement materials 16A, 16B (e.g., a portions where the aerogel framework 18A, 18B is not present).AAI-105-B-PCT (1207-WO01)

[0157] In this method, the material stack (12A, 14’’, 12B) may be exposed to light pressure during curing. As an example, light pressure may range from about 20 Pascals to about 100 Pascals. As another example, light pressure may range from about 100 g to about 500 g on an 8 inch x 8 inch sample.

[0158] In still another example, the barrier material 14 is applied to a foam reinforcement material, such as a melamine foam.

[0159] Battery

[0160] The heat control members 10A, 10B, 10C disclosed herein are highly effective insulation materials and exhibit flame resistance and resistance to grit damage. As such, the heat control members 10A, 10B, 10C may be suitable for use as thermal barriers in between batteries in battery packs or battery modules. One of the functions of the heat control members 10A, 10B, 10C is to prevent the heat transfer from a compromised battery (e.g., a battery suffering from thermal runaway) to adjacent healthy batteries. The heat control members 10A, 10B, 10C may also protect the healthy batteries from grit damages (e.g., particle bombardments of the thermal runaway ejecta).

[0161] It is to be understood that the application of the heat control members 10A, 10B, 10C of the present disclosure are not intended to be limited to applications related to insulation. The heat control members 10A, 10B, 10C can be applied to any system or application which would benefit from the unique combination of properties or procedures provided by the heat control members 10A, 10B, 10C of the present disclosure.

[0162] To further illustrate the present disclosure, examples are given herein. It is to be understood that these examples are provided for illustrative purposes and are not to be construed as limiting the scope of the present disclosure.AAI-105-B-PCT (1207-WO01)

[0163] Experimental Example 1

[0164] A barrier material precursor was generated by mixing silicon carbide powder with an aqueous sodium silicate binder. For Example A, the barrier material precursor was painted on a standalone polyvinyl alcohol 1 mm thick reinforcement fiber sheet. For Example B, the barrier material precursor was painted on a standalone CANYUE 225 reinforcement fiber sheet. For Example C, the barrier material precursor was painted on a polyvinyl alcohol 1 mm thick reinforcement fiber sheet and a PYROTHIN® aerogel thermal barrier materials (available from Aspen Aerogels) was pressed against the barrier material precursor. Each of the examples was exposed to 93°C for about 2 hours to cure the wet films and form silicon carbide barrier layers.

[0165] Each of the examples was exposed to an initial flame test. The initial flame test was carried out using a propane torch directed towards the silicon carbide barrier layer in Examples A and B, and toward the polyvinyl alcohol 1 mm thick reinforcement fiber sheet in Example C. The propane torch was located at a standoff distance of 5 inches from the respective Examples. The propane torch had two concentric rings on the nozzle exit where the outer ring emits the flame, and the inner ring is used to feed grit (which are drawn in the nozzle using a venturi action). The air and propane flow rates are adjusted such that the flame temperature is ~1100°C on the front surface of the target material. The grit periodically entrained in the flame in roughly 1 gram increments (“cycles”) was a commercially available coal slag with a D50 particle size of approximately range of 38 microns to 76 microns (μm). In this and the following experimental examples, the commercially available grit was BLACK BEAUTY® Extra Fine Coal Slag available from Harsco Corporation. Examples A, B, and C were exposed to the flame test for a maximum of five minutes.

[0166] Each of Examples A, B, and C passed the initial flame test because the silicon carbide barrier material did not burn through.AAI-105-B-PCT (1207-WO01)

[0167] Experimental Example 2

[0168] This example was performed to test the flame and grit performance of a barrier material on the surface of a hydrophobic thermal insulation layer.

[0169] In this example, two commercially available PYROTHIN® aerogel thermal barrier materials (available from Aspen Aerogels) were used as the hydrophobic thermal insulation layers (similar to layers 12A, 12B described herein).

[0170] A dispersion containing water, aluminosilicate fibers, silicon dioxide particles, and titanium dioxide particles was painted on one surface of each of the PYROTHIN® aerogel thermal barrier materials. The wet-film coated materials were exposed to 93°C for about 2 hours to cure the wet films and form coated material. These Examples are referred to as Examples D and E.

[0171] These coated materials were exposed to a flame and grit test. The propane torch with the two concentric rings as described in Example 1 was used. The device was designed to run with and without grit. Example D was exposed to the following flame and grit test: start with 10 seconds of only flame, followed by 10 - 1 second intermittent pulses of grit spaced 1 second apart, followed by 4 minutes of flame. Example E was exposed to the following flame and grit test: start with 10 seconds of only flame, followed by 13 - 1 second intermittent pulses of grit spaced 1 second apart, after which the test was stopped because a break through occurred. After the tests, macro photographic images were taken. These images are shown in Fig.3A through Fig.3D, where Fig.3A and Fig.3B are Example D (front and back, respectively) and Fig.3C and Fig.3D are Example E (front and back, respectively). As illustrated, Example D survived the flame and grit test.

[0172] Experimental Example 3

[0173] In this example, the effect of a heat diffusion layer on heat transferred through a heat control member was observed. Various aspects of a heat diffusion layer were described above in the context of Fig.1C.

[0174] Fig.4A and Fig.4B schematically illustrate the configuration of the samples tested in this Example 3. Referring to Fig.4A, the experimental configurationAAI-105-B-PCT (1207-WO01) 402 used two commercially available PYROTHIN® aerogel thermal barrier layers (available from Aspen Aerogels) as the hydrophobic thermal insulation layers 404A and 404B. The hydrophobic thermal insulation layers 404A, 404B are analogous to layers 12A, 12B described herein in the context of Fig.2B.

[0175] A heat diffusion layer 406 was formed by applying a layer of polysilazane to one of the PYROTHIN® layers and cured at 175oC for 30 minutes in air. Aspects of heat diffusion layers are described above in the context of Fig.1C. A barrier layer 408 (aspects of which are described above in Figs.1A, 2A, and 2B, among others) was formulated by applying a dispersion of a barrier material (in this experiment, silicon carbide) in a sodium silicate solution to the cured heat diffusion layer 406, and then cured at 93oC for two hours in air. Silicon carbide can facilitate diffusion of heat away from the point of flame impingement because of its thermal conductivity while also providing resistance to erosion caused by grit impingement. In this experimental example, a weight ratio of sodium silicate binder to silicon carbide barrier material was from 3:1 to 1:1. The layers were assembled to form the experimental configuration 402 shown in Fig.4A. As is described in other experimental examples, the barrier material may include other materials, such as Al2O3, Al-Si, or ZrO2. These materials may be cured at different temperatures depending on the formulation of the dispersion, as described in other experimental examples below.

[0176] As can be seen in Fig.4A, the experimental configuration 402 was exposed to a 1100oC flame using the experimental conditions described in Experimental Example 1. The temperature of the back side of the configuration 402 was measured at a location 410 approximately opposite the impinging flame.

[0177] Fig.4B illustrates experimental configuration 412, which used PYROTHIN® aerogel thermal barrier layers (available from Aspen Aerogels) as the hydrophobic thermal insulation layers 404A and 404B (similar to layers 12A, 12B described herein). The experimental configuration 412 also included two heat diffusion layers 406A, 406B between the two hydrophobic thermal insulation layers 404A, 404B. These layers were applied and cured using the same dispersions and curing conditions described above for the experimental configuration 402. In thisAAI-105-B-PCT (1207-WO01) experimental configuration 412, the heat diffusion layer 406A was in contact with the thermal barrier layer 404A and the heat diffusion layer 406B was in contact with the thermal barrier layer 404B. A layer of barrier material 408 was disposed between the two heat diffusion layers 406A, 406B.

[0178] Fig.4C illustrates a comparison of the temperature measured at a back side location 410 of configuration 402 and the temperature measured at an analogous back side location 414 of the configuration 412. The locations 410, 414 were approximately opposite the location of the flame impingement. As shown in Fig.4C, the temperature of the back side location 414 of the configuration 412, with its two heat diffusion layers 406A, 406B, and a barrier layer 408 therebetween, was consistently lower over the measurement period than the back side 410 temperature of the configuration 402 with one heat diffusion layer 406 and one barrier layer 408.

[0179] Experimental Example 4

[0180] It was found experimentally that, for configurations with a barrier layer but not a heat diffusion layer, the thermal characteristics of the barrier material influenced heat transfer through a heat control member.

[0181] Fig.5A schematically illustrates a cross-sectional view of a configuration tested in Experimental Example 4. Configuration 502 included two commercially available PYROTHIN® aerogel thermal barrier layers (available from Aspen Aerogels) as the hydrophobic thermal insulation layers 504A and 504B (similar to layers 12A, 12B described herein) with a barrier layer 506 therebetween. The barrier material was applied to one of the thermal barrier layers 504A or 504B using an aqueous sodium silicate solution that was applied and cured as described above in Experimental Example 1. Barrier materials of Al2O3, Al-Si, or ZrO2were used in independently tested samples. Each of the Al2O3, Al-Si, and ZrO2 layers was applied to one of the thermal barrier layers using a commercially available slurry. The Al2O3 slurry used was product name 634-ALP available from AREMCO PRODUCTS INC. The Al-Si slurry used was product name 634-AS-1 available from AREMCO PRODUCTS INC. The ZrO2 slurry used was 634-ZO available from AREMCO PRODUCTS INC. Each ofAAI-105-B-PCT (1207-WO01) the deposited materials was cured as described above (e.g., at 93oC for one to two hours in air). Two sets of experiments were conducted for each sample (containing the different barrier materials). In one experiment, the sample was exposed to a 1100oC flame. In the other experiment, another sample with the same barrier material was exposed to a 1100oC flame and grit that was periodically entrained in the flame as described above in Experimental Example 2, with the exception that 15 cycles of grit were applied instead of 10 cycles as described above.

[0182] Fig.5B illustrates temperatures of the various samples measured at the back side point 508 opposite the point of flame impingement. The results in Fig.5B show the stable backside temperature as a function of the thermal resistance of the barrier layer, where thermal resistance is the thickness of the barrier layer divided by the thermal conductivity of the barrier material. A barrier layer with Al2O3(which had the lowest thermal resistance and the highest hardness of the tested barrier materials (see Table 1)) showed the lowest stable temperature at back side location 508. A barrier layer with ZrO2(which had the highest thermal resistance of the tested materials) showed the highest stable temperature at back side location 508. Al-Si barrier layers, with thermal resistance between those of Al2O3 and ZrO2 showed intermediate backside temperatures. Temperatures were measured using non-contact measurements of temperature, in this case forward looking infrared (FLIR) temperature sensing.

[0183] Experimental Example 5

[0184] Table 2 illustrates results of flame testing of heat control members coated with a barrier layer that extended into the reinforcement material, as schematically illustrated in Fig.1A. For sample numbers 1, 3, and 5, the barrier material precursor indicated in Table 2 was applied to a PYROTHIN® aerogel thermal barrier layer (available from Aspen Aerogels) using the binder also indicated in Table 2. Each of the Al2O3, Al-Si, and ZrO2layers on their respective samples was exposed to 93°C for about 2 hours to cure the wet films that then formed barrier layers of theAAI-105-B-PCT (1207-WO01) corresponding material. Sample numbers 1 (ZrO2barrier material), 3 (Al2O3barrier material), and 5 (Al-Si barrier material) did not include a heat conductive layer.

[0185] Samples 2 (ZrO2 barrier material), 4 (Al2O3 barrier material), and 5 (Al-Si barrier material) were otherwise prepared in the same way as sample numbers 1, 3, and 5, except a heat diffusion layer was applied to the cured barrier layer using a dispersion of TiO2 in polysilazane. The heat diffusion layer was cured by exposure to 175°C for about 30 minutes in air.

[0186] Once prepared and assembled, each of the samples was exposed to a 1100oC flame according to the conditions described above in Experimental Example 1. No grit was applied to the samples during flame exposure.AAI-105-B-PCT (1207-WO01) Table 2 C n n k p C C C C C Cs ev en rom e expermena resu s n a e , a sampes w a heat dissipation layer (sample numbers 2, 4, and 6) exhibited lower backside temperatures than their analogous samples (1, 3, 5, respectively) without a heat dissipation layer. One sample, sample number 6 using Al-Si as a barrier material, burned through after only 1 minute of flame exposure. While not wishing to be bound by theory, it is believed that the lower hardness of Al-Si compared to ZrO2and Al2O3could have provided a weaker barrier layer. Only sample number 6 burned through, meaning that a hole developed through the entire stack of layers.

[0188] Experimental Example 6

[0189] Table 3 depicts experimental results for samples configured and composed analogously to those described in Experimental Example 5, except each sample was exposed to a flame that included periodic entrainment of grit using theAAI-105-B-PCT (1207-WO01) conditions described above in Experimental Example 1. The number of cycles applied to each sample are indicated in Table 3, where each cycle contained approximately 1 gram of grit.

[0190] As evident from the experimental results, all samples with a heat dissipation layer (sample numbers 8, 10, and 12) exhibited lower backside temperatures than their analogous samples (7, 9, 11, respectively) without a heat dissipation layer. Samples 7, 8, and 10 were observed to have burned through. Table 3 Concen. H t H t Concen. S m l Grit? Fl m B k e p C C C C oC C

[0191] Experimental Example 7

[0192] In Experimental Example 7, an aerogel component of the heat control layers (analogous to 12A and 12B) was formulated with 36 mol. % MTES and 64 mol. % TEOS and the reinforcement material was melamine foam. The binder materialAAI-105-B-PCT (1207-WO01) used for the barrier was polyvinyl alcohol. The various binder materials are indicated in Table 4. Samples 13, 15, and 17 did not include a polysilazane and TiO2heat diffusion layer, whereas Samples 14, 16, and 18 did include a polysilazane and TiO2 heat diffusion layer. No grit was applied to the samples during flame exposure.

[0193] With the exception of the Al-Si barrier material (sample number 18), all samples with a heat diffusion layer reduced the backside temperature relative to their analogs without the heat diffusion layer. No samples were observed to have burned through. Table 4 Concen. Heat Heat Concen. Sam le Grit? Flame de

[0195] Table 5 depicts experimental results for samples configured and composed analogously to those described in Experimental Example 7, except each sample was exposed to a flame that included periodic entrainment of grit. In this example, and others described herein, the grit was commercially available coal slag with a D50 particle size of approximately 1 micron (μm). The grit was entrained in theAAI-105-B-PCT (1207-WO01) flame in periodic 1 gram cycles. The number of cycles (each one approximately 1 gram) applied are indicated in Table 5.

[0196] As shown in Table 5, the application of grit within the flame caused the heat control members to burn through in sample numbers 19, 20, and 24. Backside temperature reduction was inconclusive in samples 19, 20, and 24 due to this rapid failure (in less than 1 minute). Backside temperature was reduced in sample 21 relative to its corresponding control sample 20. Samples 19, 20, and 24 were observed to have burned through. Table 5 Concen. Heat Heat Concen. Sam le Grit? Flame Back C

[0197] Experimental Example 9

[0198] Table 6 depicts experimental results for samples configured as schematically illustrated in Fig.2A. For samples 19, 21, and 23 three different fiber densities of PVA coated, wet laid glass fiber reinforcement were used. The fiber reinforcement was infused with the sol used in the fabrication of PYROTHIN® aerogelAAI-105-B-PCT (1207-WO01) thermal barrier materials (available from Aspen Aerogels) and processed to form an aerogel as described above. The reinforcement description in Table 6 indicates the grams per square meter (gsm) of fiber and that the glass fibers were coated with poly vinyl alcohol (PVA)A barrier material precursor was generated by mixing silicon carbide powder with an aqueous sodium silicate binder. The barrier material precursor was painted on the reinforced aerogel samples. Two pieces of the same fiber density were pressed together with the barrier material precursor between to form sample numbers 19, 21, and 23. Samples 19, 21, and 23 were exposed to 93°C, 175°C, and 250°C, respectively for about 1-2 hours to cure the wet films and form silicon carbide barrier layers. Once cured, the samples were exposed to a 1100oC flame for five minutes and the back side temperature measured. No grit was entrained in the flame during testing.

[0199] As shown below, each of the samples showed a reduced backside temperature relative to the 1100oC incident flame. The lowest fiber density in same 23 (34 grams / square meter) exhibited the lowest back side temperature. Without wishing to be bound by theory, it is believed that the lower fiber density reinforcement may have absorbed more of the highly insulating silica sol, thereby lowering its thermal conductivity. None of the samples were observed to have burned through. Table 6 Concen. Barrier Barrier Barrier Sample Flame Back ple Reinforcement Binder Filler Filler Tks Grit? (# Sam cycles) Time SideAAI-105-B-PCT (1207-WO01)

[0200] Experimental Example 10

[0201] Table 7 depicts experimental results for samples configured and composed analogously to those described in Experimental Example 9, except each sample was exposed to a flame that included periodic entrainment of grit, as described above. The number of cycles (each one approximately 1 gram) applied are indicated in Table 7. Sample 24 was observed to have burned through. Table 7 Concen. B rri r B rri r B rri r Sample Grit? Flame Back C C C

[0202] Experimental Example 11

[0203] Fig.6A schematically depicts a test configuration 600 for simulating a cell in thermal runaway and the effectiveness of a thermal barrier between adjacent cells. The test configuration 600 includes end plates 602A, 602B, a trigger cell 604, a heater 606, and an adjacent cell 608. A thermal barrier 610 may be disposed between the trigger cell 604 and the adjacent cell 608 to test the effectiveness of a thermal barrier.

[0204] Temperature sensors, not shown in Fig.6A for clarity, are distributed at interface I1 and interface I2. The temperatures sensors are configured to measure a cell face temperature of the corresponding cell. Specifically, temperature sensors atAAI-105-B-PCT (1207-WO01) interface I1are configured to measure a temperature of the trigger cell 604 face that confronts a first major surface of the thermal barrier 610. Similarly, temperature sensors at interface I2 are configured to measure a temperature of the adjacent cell 608 face that confronts a second major surface of the thermal barrier 610 that is opposite the first major surface.

[0205] The end plates 602A, 602B provide an adjustable frame between which cells may be placed (e.g., the trigger cell 604, the adjacent cell 608). The end plates 602A, 602B may be used to apply a pressure to the cells. This configuration has the advantage of simulating physical conditions within a battery pack. The end plates 602A, 602B may also be separated by any distance, thereby enabling different cells having different dimensions and / or different shapes to be conveniently tested without a battery module housing.

[0206] In various examples, end plates 602A, 602B may be fabricated from steel, stainless steel, aluminum, ceramics (e.g., alumina, titania), and / or alloys or combinations thereof.

[0207] The trigger cell 604 and the adjacent cell 608 may be any secondary battery composition, whether based on lithium, sodium, or any other battery chemistry that would benefit from the testing and study of thermal runaway events. The configuration of the trigger cell 604 and the adjacent cell 608 may be a prismatic cell, a pouch cell, or any other configuration that can be conveniently placed within the test configuration 600.

[0208] The trigger cell 604 is in thermal communication with the heater 606. The heater 606 may be any device that can provide sufficient thermal energy to the trigger cell 604 to trigger the uncontrolled reaction known colloquially as “thermal runaway.” For example, the heater 606 may be an electrical resistance heater, a magnesium-based ignition component, a blow torch, or other device.

[0209] The function of the trigger cell 604 within the test configuration 600 is to produce a thermal runaway event so that temperatures within the test configuration 600 may be measured. Repeated thermal runaway tests with different thermal barriers enable the performance of the thermal barriers (e.g., in preventing heatAAI-105-B-PCT (1207-WO01) transfer between cells) to be compared to one another. In this way, heat flow from the trigger cell 604 may be measured at, for example, the adjacent cell 608. Furthermore, the effectiveness of an intervening thermal barrier disposed between the trigger cell 604 and the adjacent cell 608 may be evaluated by measuring temperatures at various interfaces within the test configuration 600. In some aspects, thermocouples may be placed at one or more locations between: between the thermal barrier 610 and the trigger cell 604; between the thermal barrier 610 and the adjacent cell 608; between the adjacent cell 608 and the end plate 602A; and combinations thereof.

[0210] Fig.6B illustrates temperatures as a function of time after initiating a thermal runaway of the trigger cell 604 and the adjacent cell 608. In this experiment, a single commercially available ATB1000M® PYROTHIN® aerogel thermal barrier (available from Aspen Aerogels) was placed between the trigger cell 604 and the adjacent cell 608. The cell face temperature of the trigger cell 604 measured by sensors at interface I1is shown as the dashed line. The cell face temperature of the adjacent cell 608 measured by sensors at the interface I2is shown as the solid line. The transfer of heat from the trigger cell 604 to the adjacent cell 608 took only seconds and produced nearly the same temperature in both cells 604, 608. Also, as burning consumed energy in the trigger cell 604 and the temperature declined, the temperature of the adjacent cell 608 remained above that of the trigger cell 604. This elevated temperature of the adjacent cell 608 indicated a continued and elevated risk of initiating thermal runaway in the adjacent cell 608.

[0211] The inset of Fig.6B is a photograph taken of the “backface” of the adjacent cell, namely the interface between the adjacent cell 608 and the end plate 602A. As can be seen, this surface of the adjacent cell 608 is black from the effect of elevated temperatures.

[0212] Fig.6C illustrates temperatures as a function of time after initiating a thermal runaway of the trigger cell 604 and the adjacent cell 608. Unlike the configuration used to obtain the results shown in Fig.6B, an experimental thermal barrier 610 was disposed between the trigger cell 604 and the adjacent cell 608. In this experiment, the thermal barrier 610 was configured and composed similar to theAAI-105-B-PCT (1207-WO01) thermal barrier 10B shown in Fig.2A, in which two ATB1700 PYROTHIN® aerogel (available from Aspen Aerogels) thermal barriers were disposed on either side of a barrier material. In this experiment, the barrier material was silicon carbide dispersed in a potassium silicate binder.

[0213] Returning to Fig.6C, the cell face temperature of the trigger cell 604 measured by sensors at interface I1 is shown as the dashed line and the temperature of the cell face of the adjacent cell 608 measured by sensors at the interface I2 is shown as the solid line. Despite similar temperatures exhibited by the trigger cell 604, the adjacent cell 608 maintained a temperature below 150oC throughout the experiment time, thereby significantly reducing the transfer of heat between cells 604, 608, and the risk of thermal runaway in the adjacent cell 608.

[0214] As can be seen in the inset of Fig.6C, the backface of the adjacent cell 608 does not exhibit damage from heat and / or flame, unlike the result shown in Fig. 6B.

[0215] Various aspects of the present application are provided below:

[0216] Aspect 1 includes a heat control member that comprises a a thermal insulation layer including: a reinforcement material; and an aerogel framework incorporated with the reinforcement material; and a barrier material in contact with at least a portion of the thermal insulation layer, the barrier material being selected from the group consisting of: i) aluminum, silicon, and oxygen; ii) nitrogen and one of silicon or boron; iii) zirconia; and iv) a carbide.

[0217] Aspect 2 includes the subject matter of Aspect 1, wherein one or both of the thermal insulation layer and the aerogel framework is hydrophobic.

[0218] Aspect 3 includes the subject matter of Aspect 1 or Aspect 2, wherein the reinforcement material comprises a first major surface, a second major surface, and a thickness therebetween, and further where: the barrier material is in contact with the first major surface and incorporated into a first portion of the thickness and the aerogel framework is in contact with the second major surface and a second portion of the thickness that is greater than the first portion of the thickness.AAI-105-B-PCT (1207-WO01)

[0219] Aspect 4 includes the subject matter of any preceding Aspect, wherein the reinforcement material is selected from the group consisting of discrete fibers, a non-woven fiber batting, a glass fiber veil, a glass fiber veil including a binder, aluminosilicate fibers, and combinations thereof.

[0220] Aspect 5 includes the subject matter of any preceding Aspect, wherein the barrier material has a thickness ranging from about 50 microns to about 500 microns.

[0221] Aspect 6 includes the subject matter of any preceding Aspect, further comprising a second thermal insulation layer, wherein the barrier material is positioned between the thermal insulation layer and the second thermal insulation layer.

[0222] Aspect 7 includes the subject matter of any preceding Aspect, wherein: the second thermal insulation layer includes a second reinforcement material and a second aerogel framework incorporated with the second reinforcement material.

[0223] Aspect 8 includes the subject matter of any preceding Aspect, wherein: the reinforcement material includes a first major surface, a second major surface, and a first thickness therebetween; the second reinforcement material includes a third major surface, a fourth major surface, and a second thickness therebetween; the barrier material is in contact with the first major surface and with the third major surface and is incorporated into respective first portions of each of the first thickness and the second thickness; the aerogel framework is in contact with the second major surface and a second portion of the first thickness that is greater than the first portion of the first thickness; and the second aerogel framework is in contact with the fourth major surface and a second portion of the second thickness that is greater than the first portion of the second thickness.

[0224] Aspect 9 includes the subject matter of any preceding Aspect, wherein the reinforcement material and the second reinforcement material are independently selected from the group consisting of discrete fibers, a non-woven fiber batting, a glass fiber veil, a glass fiber veil including a binder, melamine foam, aluminosilicate fibers, and combinations thereof.AAI-105-B-PCT (1207-WO01)

[0225] Aspect 10 includes the subject matter of any preceding Aspect, wherein the barrier material further comprises sodium silicate or potassium silicate.

[0226] Aspect 11 includes the subject matter of any preceding Aspect, wherein the barrier material further includes a support structure on which the barrier material is disposed in a barrier material layer.

[0227] Aspect 12 includes the subject matter of any preceding Aspect, wherein the barrier material layer and the support structure form a free standing barrier layer, and the free standing barrier layer is in contact with the thermal insulation layer.

[0228] Aspect 13 includes the subject matter of any preceding Aspect, further comprising an encapsulation layer surrounding the free standing barrier layer and the thermal insulation layer.

[0229] Aspect 14 includes a heat control member, comprising a thermal insulation layer including: a reinforcement material; and an aerogel framework incorporated with the reinforcement material; and a barrier material in contact with at least a portion of the thermal insulation layer and formed from aluminosilicate ceramic precursors in a carrier matrix.

[0230] Aspect 15 includes the subject matter of Aspect 14, wherein the thermal insulation layer is hydrophobic and the carrier matrix includes a hydrophilic material.

[0231] Aspect 16 includes a method comprising: applying a barrier material onto a surface of each of a first thermal insulation layer and a second thermal insulation layer and; placing the surfaces of the first thermal insulation layer and the second thermal insulation layer into contact with one another; and curing the barrier material.

[0232] Aspect 17 includes the subject matter of Aspect 16, wherein: the barrier material includes one of: aluminum, silicon, and oxygen; or nitrogen and one of silicon or boron; or zirconia; or a carbide; and the applying of the barrier material involves brush coating, spray coating, or dip coating.

[0233] Aspect 18 includes a method comprising: applying a barrier material precursor onto a first major surface of a reinforcement material; curing the barrier material precursor to form a barrier material, thereby generating a compositeAAI-105-B-PCT (1207-WO01) reinforcement material; and forming an aerogel framework at a second major surface of the reinforcement material.

[0234] Aspect 19 includes a heat control member, comprising: a thermal insulation layer including: a reinforcement material; and an aerogel framework incorporated with the reinforcement material; a heat diffusion layer including a binder and a particulate material distributed throughout the binder; and a barrier material in contact with at least a portion of the thermal insulation layer, the barrier material being selected from the group consisting of: i) aluminum, silicon, and oxygen; ii) nitrogen and one of silicon or boron; iii) zirconia; and iv) a carbide.

[0235] Aspect 20 includes the subject matter of Aspect 19, wherein the heat diffusion layer is in direct contact with the thermal insulation layer and is disposed between the thermal insulation layer and the barrier material.

[0236] Aspect 21 includes the subject matter of Aspect 19 or Aspect 20, wherein: the thermal insulation layer comprises a first thermal insulation layer and a second thermal insulation layer; and the heat diffusion layer and the barrier material are disposed between the first thermal insulation layer and the second thermal insulation layer.

[0237] Aspect 22 includes the subject matter of any of Aspects 19-21, wherein the particulate material of the heat diffusion layer comprises titanium dioxide.

[0238] Aspect 23 includes the subject matter of any of Aspects 19-22, wherein the binder of the heat diffusion layer comprises polysilazane.

[0239] Aspect 24 includes the subject matter of any of Aspects 19-23, wherein the binder of the heat diffusion layer comprises sodium silicate or potassium silicate.

[0240] Aspect 25 includes the subject matter of any of Aspects 19-24, wherein the barrier material further comprises sodium silicate or potassium silicate.

[0241] Aspect 26 includes the subject matter of any of Aspects 19-25, wherein the barrier material further includes a support structure on which the barrier material is disposed in a barrier material layer.AAI-105-B-PCT (1207-WO01)

[0242] Aspect 27 includes the subject matter of any of Aspects 19-26, wherein the barrier material layer and the support structure form a free standing barrier layer, and the free standing barrier layer is contact with the thermal insulation layer.

[0243] Aspect 28 includes the subject matter of any of Aspects 19-27, further comprising an encapsulation layer surrounding the barrier layer, the heat diffusion layer, and the thermal insulation layer.

[0244] It is to be understood that any features of any of the Aspects set forth herein may be combined together in any desirable manner. For example, any combination of features of Aspect 1 and / or Aspect 2 and / or Aspect 3, etc. may be combined with any of the other Aspects disclosed herein to achieve the benefits as described in this disclosure.

[0245] Additional Notes

[0246] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

[0247] While several examples have been described in detail, it is to be understood that the disclosed examples may be modified. Therefore, the foregoing description is to be considered non-limiting.

Claims

AAI-105-B-PCT (1207-WO01) What is claimed is:

1. A heat control member, comprising: a thermal insulation layer including: a reinforcement material; and an aerogel framework incorporated with the reinforcement material; and a barrier material in contact with at least a portion of the thermal insulation layer, the barrier material being selected from the group consisting of: i) aluminum, silicon, and oxygen; ii) nitrogen and one of silicon or boron; iii) zirconia; and iv) a carbide.

2. The heat control member as defined in claim 1, wherein one or both of the thermal insulation layer and the aerogel framework is hydrophobic.

3. The heat control member as defined in claim 1 or claim 2, wherein the reinforcement material comprises a first major surface, a second major surface, and a thickness therebetween, and further where: the barrier material is in contact with the first major surface and incorporated into a first portion of the thickness and the aerogel framework is in contact with the second major surface and a second portion of the thickness that is greater than the first portion of the thickness.

4. The heat control member as defined in any preceding claim, wherein the reinforcement material is selected from the group consisting of discrete fibers, a non- woven fiber batting, a glass fiber veil, a glass fiber veil including a binder, aluminosilicate fibers, and combinations thereof.

5. The heat control member as defined in any preceding claim, wherein the barrier material has a thickness ranging from about 50 microns to about 500 microns.AAI-105-B-PCT (1207-WO01) 6. The heat control member as defined in any preceding claim, further comprising a second thermal insulation layer, wherein the barrier material is positioned between the thermal insulation layer and the second thermal insulation layer.

7. The heat control member as defined in claim 6, wherein: the second thermal insulation layer includes a second reinforcement material and a second aerogel framework incorporated with the second reinforcement material.

8. The heat control member as defined in claim 7, wherein: the reinforcement material includes a first major surface, a second major surface, and a first thickness therebetween; the second reinforcement material includes a third major surface, a fourth major surface, and a second thickness therebetween; the barrier material is in contact with the first major surface and with the third major surface and is incorporated into respective first portions of each of the first thickness and the second thickness; the aerogel framework is in contact with the second major surface and a second portion of the first thickness that is greater than the first portion of the first thickness; and the second aerogel framework is in contact with the fourth major surface and a second portion of the second thickness that is greater than the first portion of the second thickness.

9. The heat control member as defined in claim 8, wherein the reinforcement material and the second reinforcement material are independently selected from the group consisting of discrete fibers, a non-woven fiber batting, a glass fiber veil, a glass fiber veil including a binder, melamine foam, aluminosilicate fibers, and combinations thereof.AAI-105-B-PCT (1207-WO01) 10. The heat control member as defined in claim 1, wherein the barrier material further comprises sodium silicate or potassium silicate.

11. The heat control member as defined in claim 1, wherein the barrier material further includes a support structure on which the barrier material is disposed in a barrier material layer.

12. The heat control member as defined in claim 11, wherein the barrier material layer and the support structure form a free standing barrier layer, and the free standing barrier layer is in contact with the thermal insulation layer.

13. The heat control member as defined in claim 12, further comprising an encapsulation layer surrounding the free standing barrier layer and the thermal insulation layer.

14. A heat control member, comprising: a thermal insulation layer including: a reinforcement material; and an aerogel framework incorporated with the reinforcement material; and a barrier material in contact with at least a portion of the thermal insulation layer and formed from aluminosilicate ceramic precursors in a carrier matrix.

15. The heat control member as defined in claim 14, wherein the thermal insulation layer is hydrophobic and the carrier matrix includes a hydrophilic material.AAI-105-B-PCT (1207-WO01) 16. A method, comprising: applying a barrier material onto a surface of each of a first thermal insulation layer and a second thermal insulation layer and; placing the surfaces of the first thermal insulation layer and the second thermal insulation layer into contact with one another; and curing the barrier material.

17. The method as defined in claim 16, wherein: the barrier material includes one of: aluminum, silicon, and oxygen; or nitrogen and one of silicon or boron; or zirconia; or a carbide; and the applying of the barrier material involves brush coating, spray coating, or dip coating.

18. A method, comprising: applying a barrier material precursor onto a first major surface of a reinforcement material; curing the barrier material precursor to form a barrier material, thereby generating a composite reinforcement material; and forming an aerogel framework at a second major surface of the reinforcement material.

19. A heat control member, comprising: a thermal insulation layer including: a reinforcement material; and an aerogel framework incorporated with the reinforcement material; a heat diffusion layer including a binder and a particulate material distributed throughout the binder; andAAI-105-B-PCT (1207-WO01) a barrier material in contact with at least a portion of the thermal insulation layer, the barrier material being selected from the group consisting of: i) aluminum, silicon, and oxygen; ii) nitrogen and one of silicon or boron; iii) zirconia; and iv) a carbide.

20. The heat control member as defined in claim 19, wherein the heat diffusion layer is in direct contact with the thermal insulation layer and is disposed between the thermal insulation layer and the barrier material.

21. The heat control member as defined in claim 19, wherein: the thermal insulation layer comprises a first thermal insulation layer and a second thermal insulation layer; and the heat diffusion layer and the barrier material are disposed between the first thermal insulation layer and the second thermal insulation layer.

22. The heat control member as defined in claim 19, wherein the particulate material of the heat diffusion layer comprises titanium dioxide.

23. The heat control member as defined in claim 19, wherein the binder of the heat diffusion layer comprises polysilazane.

24. The heat control member as defined in claim 19, wherein the binder of the heat diffusion layer comprises sodium silicate or potassium silicate.

25. The heat control member as defined in claim 19, wherein the barrier material further comprises sodium silicate or potassium silicate.AAI-105-B-PCT (1207-WO01) 26. The heat control member as defined in claim 19, wherein the barrier material further includes a support structure on which the barrier material is disposed in a barrier material layer.

27. The heat control member as defined in claim 26, wherein the barrier material layer and the support structure form a free standing barrier layer, and the free standing barrier layer is contact with the thermal insulation layer.

28. The heat control member as defined in claim 27, further comprising an encapsulation layer surrounding the barrier layer, the heat diffusion layer, and the thermal insulation layer.

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