Battery thermal management member

Abstract

To provide battery thermal management members and systems which have durability, handleability, resistance to heat propagation and fire propagation, and favorable properties for compressibility, compressional resilience, and compliance.SOLUTION: A battery thermal management member comprises a first heat protection layer, and at least one resilient layer containing one or more organic materials. The first heat protection layer has a thermal conductivity less than about 65 mW / mK. The at least one heat protection layer maintains at least one surface of the resilient layer below a decomposition temperature of at least one of the organic materials.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 958,135, filed January 7, 2020, U.S. Provisional Patent Application No. 63 / 056,527, filed July 24, 2020, U.S. Provisional Patent Application No. 17 / 106,940, filed November 30, 2020, and U.S. Patent Application No. 17 / 106,763, filed November 30, 2020, each of which is incorporated by reference in its entirety and is controlling for any definitions of terms in this application.

[0002] [Technical field] The present invention relates generally to battery thermal management. More specifically, the present disclosure relates to compositions and systems for battery thermal management. In certain embodiments, the present disclosure relates to high performance battery thermal management compositions and systems that include aerogel technology for separating battery cells or insulating battery components. [Background technology]

[0003] Low-density aerogel materials are widely considered to be the best available solid insulators. Aerogels function as insulators primarily by minimizing conduction (low structural density results in a tortuous path for energy transfer through the solid framework), convection (large pore volume and very small pore diameter minimize convection), and radiation (with IR-absorbing or scattering dopants). Aerogels can be used in a wide range of applications, including heating and cooling insulation, acoustic insulation, electronic dielectrics, aerospace, energy storage and production, and filtration. Additionally, aerogel materials exhibit many other interesting acoustic, optical, mechanical, and chemical properties that make them highly useful in a variety of insulating and non-insulating applications.

[0004] There is a need in the electronic, industrial, and automotive fields for insulation that is suitable for reliably controlling heat flow from heat-generating components in small spaces, providing safety for such products and preventing fire spread. Insulation sheets with excellent compression properties can be useful in addressing these needs, for example, as separators in lithium-ion battery modules.

[0005] Safety standards for lithium-ion batteries include a flame exposure test, which is a test method that can determine whether a cell in a battery module experiences thermal runaway and then ignites or explodes as a result of heat propagation to other cells, including adjacent cells. Safety designs intended to prevent the propagation of thermal runaway to adjacent cells typically include the inclusion of materials with excellent insulating properties between cells.

[0006] Conventional types of insulation, such as foam or fiber sheets, can withstand high temperatures but have relatively low insulating or heat-containment capabilities. For such materials, the thickness of the insulation must be increased to provide effective thermal management. However, the space requirements of a battery module limit the size of the module and the spacing between cells within the module. Other fire-resistant materials, such as mica or ceramic sheets, can withstand high temperatures but are relatively incompressible and have low insulating capacity. Such materials may not be suitable for battery systems, such as pouch cells and prismatic cells, where cells expand and contract during operation. Similarly, it is desirable to limit the total weight of a battery module. Therefore, it is necessary to achieve resistance to heat and flame propagation while minimizing the thickness and weight of materials used to provide the necessary thermal properties while providing the desired mechanical properties for a given battery system. Different types of insulation systems, materials, and methods are needed to provide effective insulation, heat containment, and flame propagation prevention.

[0007] Aerogel materials are known to have approximately two to six times the thermal resistance of other common types of insulation, such as foams and fiberglass. Aerogels can increase effective shielding and thermal insulation without substantially increasing the thickness of the insulation or adding additional weight. Aerogels are known to be a class of structures with low density, open-cell structure, large surface area, and nanometer-scale pore sizes.

[0008] U.S. Patent Application Publication No. 2012 / 0142802 to Steinke discloses an open-cell foam filled with aerogel particles. U.S. Patent Application Publication No. 2019 / 0161909 to Oikawa discloses an insulating sheet comprising a nonwoven fabric and aerogel. However, these documents do not disclose a material or a method for producing such a material that has desirable thermal, flame, mechanical, and hydrophobic properties, as well as a combination of many desirable properties for use in battery thermal management components.

[0009] It would be desirable to provide battery thermal management components and systems that have improved performance, individually and in one or more combinations, in various aspects including compressibility, compressive resilience, compliance, thermal resistance, hydrophobicity, flame response, etc. When considering the state of the art as a whole at the time the present invention was made, it was not apparent to one skilled in the art how the shortcomings of the prior art could be overcome.

[0010] Although certain aspects of the prior art have been discussed to facilitate disclosure of the present invention, applicants have in no way denied these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the prior art aspects described herein.

[0011] The present invention may address one or more of the problems and deficiencies of the prior art. However, it is believed that the present invention may prove useful in addressing other problems and deficiencies in certain technical fields. Accordingly, the claimed invention should not be construed as necessarily limited to addressing any of the specific problems or deficiencies discussed herein.

[0012] Where any document, act, or item of knowledge is referenced or discussed in this specification, such reference or discussion is not an admission that that document, act, or item of knowledge, or any combination thereof, was publicly available, known to the public, was part of the common general knowledge, or constitutes prior art under any applicable legal provision, or is known to be relevant to any attempt to solve any of the problems to which this specification pertains. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] US Patent Application Publication No. 2012 / 0142802 [Patent Document 2] US Patent Application Publication No. 2019 / 0161909 Summary of the Invention

[0014] A long-standing and heretofore unmet need for improved aerogel compositions is now met by a new, useful, and unobvious invention.

[0015] In a general aspect, the present disclosure provides battery thermal management members and systems that are durable, easy to handle, have good resistance to heat and fire spread while minimizing the thickness and weight of the materials used, and also have good properties for compressibility, compressive resilience, and compliance.

[0016] In an exemplary aspect, the present disclosure provides a battery thermal management member including a thermal protection layer and a resilient layer, e.g., the resilient layer includes one or more organic materials. In an exemplary embodiment, the thermal protection layer has a thermal conductivity of less than about 65 mW / mK, e.g., the thermal protection layer can maintain at least one surface of the resilient layer below the decomposition temperature of at least one of the organic materials.

[0017] In some embodiments, the thermal protection layer is disposed adjacent to the elastic layer. In some embodiments, the thermal protection layer is disposed in contact with the at least one elastic layer. In some embodiments, the battery thermal management member includes a second thermal protection layer. In such embodiments, the first thermal protection layer and the second thermal protection layer can be disposed on opposite sides of the at least one elastic layer. For example, at least one of the first thermal protection layer and the second thermal protection layer can be disposed in contact with the at least one elastic layer.

[0018] In any of the above embodiments, the elastic layer can include a compressible material. In some embodiments, the compressible material has a chemical decomposition temperature greater than about 200°C. In some embodiments, the compressible material has a chemical decomposition temperature greater than about 240°C. In some embodiments, the compressible material has a chemical decomposition temperature greater than about 280°C. In some embodiments, the compressible material has a chemical decomposition temperature in a range from about 200°C to about 300°C. In some embodiments, the compressible material has a chemical decomposition temperature greater than about 300°C. In some embodiments, the compressible material has a chemical decomposition temperature greater than about 350°C. In some embodiments, the compressible material has a chemical decomposition temperature in a range from about 300°C to about 400°C.

[0019] In an exemplary embodiment, the compressible material comprises a material selected from the group consisting of siloxane, polyolefin, polyurethane, phenolic, melamine, cellulose acetate, and polystyrene. In an exemplary embodiment, the thermal protection layer comprises a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof. For example, at least one of the first and second thermal protection layers can comprise a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof. In another example, both the first and second thermal protection layers can comprise a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof.

[0020] In some embodiments, the thermally protective layer comprises an aerogel composition. For example, at least one of the first and second thermally protective layers can comprise an aerogel composition. In another example, both the first and second thermally protective layers can comprise an aerogel composition. The aerogel of the aerogel composition can comprise an inorganic, organic, or inorganic / organic hybrid material. In an exemplary embodiment, the aerogel composition is a silica aerogel composition. The aerogel composition can include a reinforcing material. For example, a reinforcing material is present in the aerogel composition. In some embodiments, the reinforcing material comprises fibers. For example, the fibers can be selected from the group consisting of discrete fibers, woven materials, nonwoven materials, needled nonwovens, battings, webs, mats, felts, and combinations thereof.

[0021] In another general aspect, the present disclosure provides aerogel compositions, e.g., reinforced aerogel compositions, that are durable, easy to handle, have good resistance to heat and fire propagation while minimizing the thickness and weight of the materials used, and also have good properties for compressibility, compressive resilience, and compliance. In another general aspect, the present disclosure provides thermal control elements or battery thermal management elements that include the aerogel compositions, reinforced aerogel compositions, or combinations thereof. For example, a thermal control element or battery thermal management element according to embodiments disclosed herein can include at least one layer of the aerogel composition or the reinforced aerogel composition. In another example, a thermal control element or battery thermal management element according to embodiments disclosed herein can include multiple layers of the aerogel composition or the reinforced aerogel composition.

[0022] In exemplary aspects, the present disclosure provides a thermal control element or battery thermal management element comprising an aerogel composition. In certain embodiments, the thermal control element or battery thermal management element is substantially flat and has a first outer major surface and a second outer major surface. In exemplary embodiments, the aerogel composition includes one or more additives. The additives can be present at a level of about 5 to 20% by weight of the aerogel composition in some embodiments. The additives can be present at a level of about 10 to 20% by weight of the aerogel composition in some embodiments. In certain embodiments, the thermal control element or battery thermal management element has a thermal conductivity of less than about 40 mW / mK. In exemplary embodiments, the thermal control element or battery thermal management element comprises multiple layers of the aerogel composition.

[0023] In another exemplary aspect, the present disclosure provides a thermal control or battery thermal management component comprising at least one layer of an aerogel composition, at least one compliant member, and a heat-capacitive material. The aerogel composition comprises one or more additives, the additives being present at a level of at least about 5 to 20% by weight of the aerogel composition. In some embodiments, the additives can be present at a level of about 10 to 20% by weight of the aerogel composition. In exemplary embodiments, the thermal control or battery thermal management component comprises multiple layers of the aerogel composition. In some embodiments, a heat-capacitive material is disposed between at least two layers of the aerogel composition. The heat-capacitive material can be any material having a specific heat capacity of at least about 0.3 J / (gC). In some embodiments, the material with thermal capacitance has a specific heat capacity of at least about 0.5 J / (gC). For example, the heat-capacitive material can include at least one layer comprising a metal. In exemplary embodiments, at least one compliant member can comprise a compressible material, i.e., a material that can be compressed to reduce its thickness while imparting a desired resistance to compression. For example, the compliant member can comprise a material selected from the group consisting of polyolefin, polyurethane, phenolic, melamine, cellulose acetate, and polystyrene. The compliant member can be disposed adjacent to the aerogel composition or the heat-capacitive material. In exemplary embodiments, the compliant member is between at least two layers of the aerogel composition. In some embodiments, the compliant member is disposed between both a layer of the aerogel composition and a layer of the heat-capacitive material.

[0024] In some embodiments, the thermal control or battery thermal management component has a thermal conductivity of less than about 30 mW / mK, less than about 25 mW / mK, less than about 20 mW / mK, less than about 18 mW / mK, less than about 16 mW / mK, less than about 14 mW / mK, less than about 12 mW / mK, less than about 10 mW / mK, less than about 5 mW / mK, or a range between any combination of the foregoing thermal conductivities. In exemplary embodiments, the one or more additives include a fire-class additive. In exemplary embodiments, the one or more additives include an opacifier. In some embodiments, the one or more additives include a combination of a fire-class additive and an opacifier. For example, the one or more additives can include a clay mineral, such as kaolin. In another example, the one or more additives can be selected from the group consisting of boron carbide, diatomaceous earth, manganese ferrite, MnO, NiO, SnO, AgO, BiO, carbon black, graphite, 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, silicon carbide, titanium carbide, tungsten carbide, or mixtures thereof. In a preferred embodiment, the one or more additives include silicon carbide.

[0025] In exemplary embodiments, when the first major exterior surface is exposed to a temperature of 650°C or greater, the thermal control member or battery thermal management member maintains a temperature of 120°C or less on the second major exterior surface for at least about 1 minute. In some embodiments, when the first major exterior surface is exposed to a temperature of 650°C or greater, the thermal control member or battery thermal management member maintains a temperature of 75°C or less on the second major exterior surface for at least about 30 seconds. In some embodiments, when the first major exterior surface is exposed to a temperature of 650°C or greater, the thermal control member or battery thermal management member maintains a temperature of 150°C or less on the second major exterior surface for at least about 90 seconds. In some embodiments, when the first major exterior surface is exposed to a temperature of 650°C or greater, the thermal control member or battery thermal management member maintains a temperature of 150°C or less on the second major exterior surface for at least about 90 seconds. In some embodiments, the thermal control member or battery thermal management member maintains a temperature of 170° C. or less at the second major exterior surface for at least about 90 seconds when the first major exterior surface is exposed to a temperature of 650° C. or greater. In some embodiments, the thermal control member or battery thermal management member maintains a temperature of 180° C. or less at the second major exterior surface for at least about 2 minutes, preferably at least about 4 minutes, when the first major exterior surface is exposed to a temperature of 650° C. or greater.

[0026] In another embodiment, these thermal profiles are achieved when the thermal control member or battery thermal management member is incorporated into an electric vehicle system with other components in various configurations and environments. For example, the thermal control member or battery thermal management member can be integrated into a system such as a battery system where the thermal control member or battery thermal management member and other components may be subjected to ambient pressures, temperatures, and compression (including from gases other than air).

[0027] In exemplary embodiments, the aerogel composition has an uncompressed thickness ranging from about 1 mm to about 10 mm. For example, the aerogel composition can have an uncompressed thickness ranging from about 1 mm to about 5 mm. In other examples, the aerogel composition can have an uncompressed thickness of about 2 mm, about 3 mm, or about 4 mm.

[0028] In certain embodiments, the aerogel composition has a density of about 0.60 g / cm 3 Below, about 0.50g / cm 3 Below, about 0.40g / cm 3 Below, approximately 0.30g / cm 3 Below, approximately 0.25g / cm 3 Below, about 0.20g / cm 3 Below, approximately 0.18g / cm 3 Below, approximately 0.16g / cm 3 Below, approximately 0.14g / cm 3 Below, approximately 0.12g / cm 3 Below, approximately 0.10g / cm 3 Below, approximately 0.05g / cm 3 Below, approximately 0.01g / cm 3 In an exemplary embodiment, the aerogel composition has a density of about 0.3 g / cm or less, or in the range between any two of these values. 3 has a density of less than

[0029] In an exemplary aspect, the present disclosure provides a battery module including a first battery cell, a second battery cell, and a thermal control or battery thermal management member according to an embodiment disclosed herein disposed between at least the first battery cell and the second battery cell.

[0030] In an exemplary aspect, the present disclosure provides a battery module or battery pack including at least one battery cell and a thermal control member or battery thermal management member according to an embodiment disclosed herein disposed on the battery cell or battery module, e.g., on a surface of the at least one battery cell or on a surface of the battery module. For example, the battery module or battery pack has an interior surface and an exterior surface. In certain embodiments, the thermal control member or battery thermal management member is on the interior surface of the battery module or battery pack. In certain embodiments, the thermal control member or battery thermal management member is on the exterior surface of the battery module or battery pack.

[0031] In exemplary embodiments, the thermal control or battery thermal management component comprises an aerogel composition. In some embodiments, the thermal control or battery thermal management component has an energy absorption capacity ranging from about 25 J / g to about 225 J / g.

[0032] In embodiments of aspects disclosed herein, a reinforcing material can be included. For example, the reinforcing material can include fibers. For example, the reinforcing material can be selected from the group consisting of discrete fibers, woven materials, nonwoven materials, needled nonwovens, batting, webs, mats, felts, and combinations thereof. In some embodiments, the reinforcing material includes an open-cell macroporous framework ("OCMF") material. For example, the OCMF material can include a melamine-based foam or a urethane-based polymer foam. In other embodiments, the reinforcing material can include a combination of fibers and an OCMF material.

[0033] In embodiments of aspects disclosed herein, the thermal control member or battery thermal management member can have an uncompressed thickness ranging from about 2 mm to about 10 mm. For example, the thermal control member or battery thermal management member can have an uncompressed thickness of about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, or a range between any of the aforementioned thicknesses. In exemplary embodiments, the thermal control member or battery thermal management member can have an uncompressed thickness ranging from about 2 mm to about 7 mm.

[0034] In some embodiments of aspects disclosed herein, the thermal control element or battery thermal management element can further include an encapsulation element forming at least one of the first or second exterior surfaces. For example, the aerogel composition can comprise the encapsulation element. The encapsulation element can include, for example, an encapsulation layer or coating surrounding the aerogel composition and / or the thermal control element or battery thermal management element. The encapsulation element can include at least one vent to allow air to enter and exit the panel, and in some embodiments, a particulate filter to retain particulate matter within the encapsulation element.

[0035] In exemplary embodiments, the aerogel composition of the thermal control or battery thermal management component is hydrophobic, for example, the aerogel composition has a liquid water absorption rate of less than about 15% by weight.

[0036] In exemplary embodiments, the aerogel of the aerogel composition comprises an inorganic, organic, or inorganic / organic hybrid material. For example, the aerogel composition is a silica aerogel composition. In certain embodiments, the aerogel composition comprises alkylated silica.

[0037] In certain embodiments, the aerogel composition is tall. For purposes of this patent, a tall aerogel composition is defined as an aerogel composition that exhibits bulk and some elastic properties (either with or without full bulk recovery). In certain embodiments, a tall aerogel composition is (i) compressible to at least 50%, preferably at least 65%, and most preferably at least 80% of its original or uncompressed thickness, and (ii) sufficiently elastic to return to at least 70%, preferably at least 75%, and most preferably at least 80% of its original or uncompressed thickness after being compressed for several seconds.

[0038] In some embodiments, the reinforcing material can include a reinforcement including multiple layers of material. For example, the multiple layers of material can be bonded together. In an exemplary embodiment, at least one of the multiple layers can include a first material, and at least one other of the multiple layers can include a second material. The first material and the second material can have the same or different material properties. For example, the first material can be more compressible than the second material. In another example, the first material can include closed-cell foam, and the second material can include closed-cell foam.

[0039] In some embodiments of the aspects disclosed herein, the thermal control element or battery thermal management element can include multiple layers. For example, the thermal control element or battery thermal management element can include at least one layer of a thermally conductive material, or a layer including a thermally conductive material, e.g., the layer includes a metal, carbon, a thermally conductive polymer, or a combination thereof. As used in the context of these embodiments, a thermally conductive material refers to a material having a thermal conductivity greater than that of the aerogel composition. In certain embodiments, the thermally conductive material has a thermal conductivity greater than that of the aerogel composition by at least about one order of magnitude. In some embodiments, the thermal control element or battery thermal management element can include multiple layers of the aerogel composition. In certain embodiments, the thermal control element or battery thermal management element can include at least one layer of an electrically conductive material disposed adjacent to the aerogel composition. In certain embodiments, the thermal control element or battery thermal management element can include at least one layer of an electrically conductive material disposed between at least two of the multiple layers of the aerogel composition. In some embodiments, the thermal control element or battery thermal management element can include particles of an electrically conductive material disposed within a layer of the thermal control element or battery thermal management element, for example, within a layer of an aerogel composition.

[0040] In exemplary embodiments, the thermal control element or battery thermal management element can include a material or layer of material that provides thermal capacitance (i.e., a heat-capacitive material), e.g., a material having a specific heat capacity of at least about 0.3 J / (gC). In some embodiments, the material with thermal capacitance has a specific heat capacity of at least about 0.5 J / (gC). For example, the material providing thermal capacitance can include a metal such as aluminum, titanium, nickel, steel, iron, or a combination thereof. In some embodiments, the thermal control element or battery thermal management element can include a layer or coating of a material with thermal capacitance. In some embodiments, the thermal control element or battery thermal management element can include particles of a material that provides thermal capacitance disposed within a layer of the thermal control element or battery thermal management element, e.g., within a layer of an aerogel composition. In certain embodiments, the thermal control element or battery thermal management element can include at least one layer of a material with thermal capacitance disposed adjacent to an aerogel composition. In certain embodiments, the thermal control element or battery thermal management element can include at least one layer of a material with thermal capacitance disposed between at least two of a plurality of layers of an aerogel composition. In exemplary embodiments, the thermal control element or battery thermal management element can include both a thermally conductive material and a thermally capacitive material. For example, the thermal control element or battery thermal management element can include a material that has both thermal capacitance and thermal conductivity, such as a metal, such as aluminum, titanium, nickel, steel, iron, or a combination thereof. In another example, the thermal control element or battery thermal management element can include one or more different materials or layers of materials, each having either thermal capacitance, thermal conductivity, or a combination thereof, such as a layer including a metal and a layer including a thermally conductive polymer.

[0041] In some embodiments, thermal paste can be used between layers of a thermal control or battery thermal management component to ensure uniform and consistent heat transfer between such layers. As used herein, thermal paste refers to various materials also known as thermal compounds, thermal greases, thermal interface materials (TIMs), thermal gels, heat pastes, heat sink compounds, and heat sink pastes. For example, a layer of thermal paste can be disposed between an aerogel composition and another layer, such as one or more layers containing a thermally conductive or heat-capacitive material.

[0042] In embodiments of the aspects disclosed herein, the composition can further include at least one facing layer, as described in more detail below. For example, the facing layer can be a layer selected from the group consisting of a polymer sheet, a metal sheet, a fiber sheet, and a woven fabric sheet. In exemplary embodiments, the facing layer can include an electrically conductive material, a material with heat capacity, or a combination thereof. In some embodiments, the facing layer can be attached to the composition by an adhesive mechanism selected from the group consisting of, for example, an aerosol adhesive, a urethane-based adhesive, an acrylate adhesive, a hot melt adhesive, an epoxy, a rubber-resin adhesive, a polyurethane composite adhesive, and combinations thereof. In some embodiments, the facing layer can be attached to the composition by a non-adhesive mechanism selected from the group consisting of, for example, flame glue, stitching, a sealing bag, a rivet, a button, a clamp, a wrap, a brace, and combinations thereof. In some embodiments, the facing layer can be attached to the composition using any combination of the above-mentioned adhesive and non-adhesive mechanisms. In some embodiments of the above aspects, the thermal control element or battery thermal management element can further include at least one layer of an electrically conductive material or a heat capacity material. For example, at least one layer of conductive or heat-capacitive material can include a metal, carbon, a conductive polymer, or a combination thereof. In some examples, at least one layer of conductive material including carbon can be a highly oriented graphite material, such as a pyrolytic graphite sheet or similar material.

[0043] In embodiments of aspects disclosed herein, the one or more additives are selected from the group consisting of boron carbide, diatomaceous earth, manganese ferrite, MnO, NiO, SnO, AgO, BiO, carbon black, graphite, 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, silicon carbide, titanium carbide, tungsten carbide, or mixtures thereof. In certain embodiments, the one or more additives can include silicon carbide. In certain embodiments, the one or more additives exclude silicon carbide whiskers or fibers.

[0044] In some embodiments, the aerogel composition further comprises one or more additional additives. For example, the one or more additional additives comprise a fire-class additive. In these or other embodiments of the above aspects, the composition is low-flammable, non-flammable, low-combustible, or non-flammable. In some embodiments, the additive comprises a clay mineral, such as kaolin. In these or other embodiments, the one or more additives comprise a combination of a fire-class additive and an opacifier.

[0045] Additionally, the aerogel materials or frameworks of various embodiments of the present disclosure are implemented using aerogel particle-based slurries or suspensions infiltrated with the reinforcing materials described in various embodiments. Various embodiments of the present disclosure can be implemented with non-particulate aerogel materials produced in situ using a variety of methods, including infiltrating the reinforcing materials with various gel precursors in an appropriate solvent, followed by the use of supercritical fluids, or by removing the solvent at elevated temperatures and ambient or subcritical pressures.

[0046] In separate embodiments, the present disclosure includes a thermal control or battery thermal management component comprising an aerogel composition, such as an OCMF-reinforced or fiber-reinforced aerogel composition, and including one or more, or even all, of the features and characteristics described above, including various combinations and methods of manufacture thereof.

[0047] Embodiments of the thermal barrier and aerogel compositions disclosed herein are useful for isolating, insulating, and protecting battery cells or battery components of any configuration, such as pouch cells, cylindrical cells, prismatic cells, and packs and modules incorporating or including any such cells. The thermal barrier and aerogel compositions disclosed herein are useful for lithium-ion batteries, solid-state batteries, and any other energy storage device or technology where isolation, insulation, and protection are required.

[0048] These and other important objects, advantages, and features of the present invention will become apparent as the present disclosure proceeds.

[0049] The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the disclosure which follows, the scope of the invention being indicated in the claims. [Brief explanation of the drawings]

[0050] [Figure 1] 1 is a chart illustrating a thermal control element or battery thermal management element that controls time-temperature behavior according to certain embodiments disclosed herein. [Figure 2] 1 is a chart illustrating a thermal control element or battery thermal management element that controls time-temperature behavior according to certain embodiments disclosed herein. [Figure 3] 1 is a chart illustrating the relationship between stress and strain for a thermal control or battery thermal management member according to certain embodiments disclosed herein. [Figure 4] 1 is a chart illustrating a thermal control element or battery thermal management element that controls time-temperature behavior according to certain embodiments disclosed herein. [Figure 5] 1 illustrates an exemplary thermal control or battery thermal management member, according to certain embodiments disclosed herein. [Figure 6] 1A and 1B illustrate schematic diagrams of thermal control or battery thermal management components according to certain embodiments disclosed herein. [Figure 7]1A and 1B illustrate schematic diagrams of thermal control or battery thermal management components according to certain embodiments disclosed herein. [Figure 8] 1A and 1B illustrate schematic diagrams of thermal control or battery thermal management components according to certain embodiments disclosed herein. [Figure 9] 1A and 1B illustrate schematic diagrams of thermal control or battery thermal management components according to certain embodiments disclosed herein. [Figure 10] 1A and 1B illustrate schematic diagrams of thermal control or battery thermal management components according to certain embodiments disclosed herein. [Figure 11] 1A and 1B illustrate schematic diagrams of thermal control or battery thermal management components according to certain embodiments disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0051] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and which show, by way of illustration, specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

[0052] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0053] As used herein, "about" means approximately or in the vicinity, and refers to ±5% of a numerical value in the context of a stated numerical value or range. In embodiments, the term "about" can include conventional rounding to significant figures of numerical values. Also, "about 'x' to 'y'" includes "about 'x' to about 'y'."

[0054] As used herein, the terms "composition" and "complex" are used interchangeably.

[0055] Aerogels are a class of open-cell porous materials containing an interconnected skeleton and a corresponding network of pores embedded within the skeleton, with an interstitial phase within the pore network composed primarily of a gas, such as air. Aerogels are typically characterized by low density, high porosity, large surface area, and small pore size. Aerogels can be distinguished from other porous materials by their physical and structural properties.

[0056] Within the context of this disclosure, the term "aerogel" or "aerogel material" refers to a gel that includes a skeleton of an interconnected structure with a corresponding network of interconnected pores embedded within the skeleton and that contains a gas, such as air, as a dispersed pore medium, and that exhibits the following properties that are attributed to aerogels: (a) an average pore size ranging from about 2 nm to about 100 nm; (b) a porosity of at least 80% or greater; and (c) a porosity of at least about 100 nm. 2 It is characterized by the physical and structural properties of a surface area of ​​more than 1 / g (as determined by nitrogen porosimetry testing).

[0057] Thus, the aerogel materials of the present disclosure include any aerogel or other open-cell material that meets the clarifying criteria set forth in the previous paragraph, and also includes materials that can be classified as xerogels, cryogels, ambigels, microporous materials, etc.

[0058] Aerogel materials may also be further characterized by additional physical properties, including: (d) a pore volume of about 2.0 mL / g or greater, particularly about 3.0 mL / g or greater; (e) a density of about 0.50 g / cc or less, particularly about 0.3 g / cc or less, and more particularly about 0.25 g / cc or less; and (f) at least 50% of the total pore volume comprising pores having a pore diameter between 2 and 50 nm (although embodiments disclosed herein include aerogel structures and compositions containing pores having a pore diameter greater than 50 nm, as described in more detail below). However, these additional properties are not required for characterization of a compound as an aerogel material.

[0059] Within the context of this disclosure, the term "innovative processing and extraction techniques" refers to methods of replacing the liquid interstitial phase of a wet gel material with a gas, such as air, in a manner that causes low pore collapse and low shrinkage of the gel's skeletal structure. 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 resulting from the evaporation or removal of the liquid can cause significant pore shrinkage and skeletal collapse within the gel material. The use of innovative processing and extraction techniques during the extraction of the liquid interstitial phase reduces the adverse effects of capillary forces on the pores and gel skeleton during liquid extraction (also known as solvent removal or drying).

[0060] In certain embodiments, innovative processing and extraction techniques use near- or supercritical fluids or near- or supercritical conditions to extract the liquid interstitial phase from the wet gel material. This can be achieved 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 exchange can be used to optimize the near- or supercritical fluid extraction process.

[0061] In certain embodiments, innovative processing and extraction techniques involve modifying the gel skeleton to reduce the irreversible effects of capillary pressure and other mass transfer limitations at the liquid-vapor interface. This embodiment can include treating the gel skeleton with a hydrophobizing or other functionalizing agent that enables the gel skeleton to withstand or recover from any disruptive forces during liquid extractions performed below the critical point of the liquid interstitial phase. This embodiment can also include incorporating functional groups or scaffold elements that impart a sufficiently high scaffold elastic modulus to the gel skeleton to withstand or recover from any disruptive forces during liquid extractions performed below the critical point of the liquid interstitial phase.

[0062] In the context of this disclosure, the term "skeleton" or "skeletal structure" refers to a network of interconnected oligomers, polymers, or particles that form the solid structure of a material. In the context of this disclosure, the term "aerogel skeleton" or "aerogel skeleton structure" refers to a network of interconnected oligomers, polymers, or colloidal particles that form the solid structure of a gel or aerogel. The polymers or particles that make up the aerogel skeleton structure typically have diameters of about 100 angstroms. However, the skeleton structure of this disclosure can also include a network of interconnected oligomers, polymers, or colloidal particles of any diameter size that form a solid structure within a material such as a gel or aerogel. Furthermore, the term "silica-based aerogel" or "silica-based aerogel skeleton" refers to an aerogel skeleton in which silica comprises at least 50% (by weight) of oligomers, polymers, or colloidal particles that form the solid skeleton structure within the gel or aerogel.

[0063] In the context of this disclosure, the term "aerogel composition" refers to any composite material that includes an aerogel material as a component of the composite. Examples of aerogel compositions include, but are not limited to, fiber-reinforced aerogel composites, aerogel composites containing added elements such as opacifiers, aerogel composites reinforced by an open-cell macroporous skeleton, aerogel-polymer composites, and composites in which aerogel particulates, particles, granules, beads, or powders are combined with binders, resins, cements, foams, polymers, or similar solid materials to incorporate them into a solid or semi-solid material. Aerogel compositions are generally obtained after removing the solvent from the various gel materials disclosed herein. The aerogel compositions thus obtained may be further subjected to additional processing or treatment. The various gel materials may also be subjected to additional processing or treatment otherwise known or useful in the art before being subjected to solvent removal (or liquid extraction or drying).

[0064] In the context of this disclosure, the term "monolithic" refers to an aerogel material in which the majority (by weight) of the aerogel contained in the aerogel material or composition is in the form of an integral, interconnected aerogel nanostructure. Monolithic aerogel materials include aerogel materials that are initially formed to have an integral, interconnected gel or aerogel nanostructure, but that subsequently crack, break, or split into non-integral aerogel nanostructures. Monolithic aerogel materials are distinguished from granular aerogel materials. The term "granular aerogel material" refers to an aerogel material in which the majority (by weight) of the aerogel contained in the aerogel material is in the form of particulates, particles, granules, beads, or powder, which may be bonded or compressed together but lack interconnected aerogel nanostructures between individual particles.

[0065] In the context of this disclosure, the term "wet gel" refers to a gel in which the mobile pore phase within a network of interconnected pores is composed primarily of a liquid, such as a conventional solvent, a liquefied gas, such as liquid carbon dioxide, or a combination thereof. Aerogels typically require the initial generation of a wet gel, followed by innovative processing and extraction to exchange the gel's mobile pore liquid for air. Examples of wet gels include, but are not limited to, alcogels, hydrogels, ketogels, carbonogels, and any other wet gels known to those skilled in the art.

[0066] The aerogel compositions of the present disclosure may include reinforced aerogel compositions. In the context of this disclosure, the term "reinforced aerogel composition" refers to an aerogel composition that includes a reinforcing phase within the aerogel material, where the reinforcing phase is not part of the aerogel skeleton itself. The reinforcing phase may be any material that imparts enhanced flexibility, resilience, conformability, or structural stability to the aerogel material. Examples of well-known reinforcing materials include, but are not limited to, open-cell macroporous skeletal reinforcement materials, closed-cell macroporous skeletal reinforcement materials, open-cell membranes, honeycomb reinforcement materials, polymeric reinforcement materials, and fibrous reinforcement materials such as discrete fibers, woven fabrics, nonwoven fabrics, needled nonwoven fabrics, battings, webs, mats, and felts.

[0067] In the context of this disclosure, the term "fiber-reinforced aerogel composition" refers to a reinforced aerogel composition that includes a fiber-reinforced material as the reinforcing phase. Examples of fiber-reinforced materials include, but are not limited to, discrete fibers, woven materials, nonwoven materials, batts, batting, webs, mats, felts, or combinations thereof. Fiber-reinforced materials may be polyester, polyolefin terephthalate, poly(ethylene) naphthalate, polycarbonate (e.g., rayon, nylon), cotton (e.g., Lycra from DuPont), carbon (e.g., graphite), polyacrylonitrile (PAN), oxidized PAN, non-carbonized heat-treated PAN (e.g., from SGL Carbon), glass or fiberglass-based materials (such as S-glass, 901-glass, 902-glass, 475-glass, and E-glass), quartz-like silica-based fibers (e.g., quartz glass from Saint-Gobain), Q-felt (from Johns-Manville), Safil (Safil), and other materials. Other materials include: Durablanket (Uniflax) and other silica fibers; Duraback (Carborundum); polyaramid fibers such as Kevlar, Nomex, and Zontella (all manufactured by DuPont); Conex (Taijin); polyolefins such as Tyvek (DuPont), Dyneema (DSM), and Spectra (Honeywell); other polypropylene fibers such as Typar and Xavan (DuPont); fluoropolymers such as PTFE (Teflon) and Goretex (WLGORE); Nicalon (COI) The glass or glass fiber based fiber reinforcement materials can include a variety of materials, including, but not limited to, silicon carbide fibers such as those from Ceramics, ceramic fibers such as Nextel (3M), acrylic polymers, wool fibers, silk, linen, leather, suede, PBO-Zylon fibers (Tyobo), liquid crystal materials such as Vectan (Hoechst), Cambrelle fibers (DuPont), polyurethane, polyamide, wood fibers, boron, aluminum, iron, stainless steel fibers, and other thermoplastics such as PEEK, PES, PEI, PEK, and PPS. Glass or glass fiber based fiber reinforcement materials can be manufactured using one or more techniques.In certain embodiments, it may be desirable to fabricate them using a carding and cross-wrapping or airlaid process. In exemplary embodiments, carding and cross-wrapping glass or glass fiber-based fiber reinforcement materials offers certain advantages over airlaid materials. For example, carding and cross-wrapping glass or glass fiber-based fiber reinforcement materials can provide consistent material thickness for a given basis weight of reinforcement material. In certain additional embodiments, it may be desirable to further needle the fiber reinforcement material, which requires interlacing the fibers in the z-direction, to improve the mechanical and other properties of the final aerogel composition.

[0068] The reinforced aerogel compositions of the present disclosure may include aerogel compositions reinforced with an open-cell macroporous framework material. In the context of this disclosure, the term "open-cell macroporous framework" or "OCMF" refers to a porous material comprising an interconnected framework of substantially uniform composition, with a corresponding network of interconnected pores embedded within the framework, characterized by an average pore size ranging from about 10 μm to about 700 μm. Such average pore size may be measured by known techniques, including, but not limited to, microscopy using optical analysis. Accordingly, the OCMF materials of the present disclosure include any open-cell materials that meet the clarifying criteria described in this paragraph, including compounds that would otherwise be classified as foams, foam-like materials, macroporous materials, etc. OCMF materials have void volumes within the framework, making them distinct from materials that comprise an interconnected framework that does not have a uniform composition, such as a collection of fibers and binders with void volumes within a fiber matrix.

[0069] In the context of this disclosure, the term "substantially uniform composition" refers to uniformity of the composition of the referenced material within a tolerance of 10%.

[0070] In the context of this disclosure, the term "OCMF-reinforced aerogel composition" refers to a reinforced aerogel composition comprising an open-cell macroporous framework material as the reinforcing phase. OCMF materials suitable for use in this disclosure include, but are not limited to, OCMF materials made from organic polymeric materials. Examples include OCMF materials made from polyolefins, polyurethanes, phenols, melamine, cellulose acetate, and polystyrene. In the context of this disclosure, the term "organic OCMF" refers to an OCMF material having a framework composed primarily of organic polymeric materials. In certain embodiments, OCMF materials made from melamine or melamine derivatives are also preferred. In the context of this disclosure, the term "melamine OCMF" or "melamine-based OCMF" refers to an organic OCMF material having a framework composed primarily of a polymeric material derived from reacting melamine with a condensing agent, such as formaldehyde. Examples of OCMF materials made from melamine or melamine derivatives for use in this disclosure are provided in U.S. Patent Nos. 8,546,457, 4,666,948, and WO 2001 / 094436. The term "inorganic OCMF" refers to an OCMF material having a skeleton composed primarily of inorganic materials. Examples of inorganic OCMF include, but are not limited to, cementitious materials, gypsum, and calcium silicate.

[0071] In the context of this disclosure, the term "foam" refers to a material formed by dispersing a proportion of gas in the form of bubbles into a liquid or resin foam material, such that the material comprises a skeleton of an interconnected polymeric structure of substantially uniform composition, with a corresponding network or collection of pores embedded within the skeleton, retaining the bubbles as the foam solidifies into a solid structure. Generally, foams can be produced using a wide variety of processes; see, for example, U.S. Patent Nos. 6,147,134, 5,889,071, 6,187,831, and 5,229,429. Thus, foam materials of the present disclosure include any material that meets the clarifying criteria set forth in this paragraph, including compounds that would otherwise be classified as OCMF materials, macroporous materials, and the like. Foams as defined in this disclosure can be of the thermoplastic, elastomer, and thermoset (duromer) types.

[0072] Pores within a solid framework may also be referred to as "cells." Cells can be divided by cell walls or membranes, creating a collection of independent, closed pores within the porous material. The term "closed-cell" refers to a porous material in which at least 50% of the pore volume is substantially confined by membranes or walls. Cells in a material can also be interconnected through cell openings, forming a network of interconnected open pores within the material. The term "open-cell" refers to a porous material in which at least 50% of the pore volume is open. Open-cell materials can include reticulated open-cell materials, non-reticulated open-cell materials, or combinations thereof. Reticulated materials are open-cell materials produced by a reticulation process that eliminates or punctures the membranes of cells within the porous material. Reticulated materials typically have a higher concentration of open cells than non-reticulated materials, but tend to be more expensive and difficult to manufacture. Generally, porous materials do not have an entirely single type of cell structure (either open or closed). Porous materials can be produced using a wide variety of processes, including the foam manufacturing processes set out in U.S. Pat. Nos. 6,147,134, 5,889,071, 6,187,831, 5,229,429, 4,454,248, and U.S. Patent Application Publication No. 2007 / 0213417.

[0073] In the context of this disclosure, the terms "aerogel blanket" or "aerogel blanket composition" refer to an aerogel composition reinforced with a continuous sheet of reinforcing material. Aerogel blanket compositions are distinguishable from other reinforced aerogel compositions that are reinforced with discontinuous reinforcing materials, such as isolated aggregates or chunks of reinforcing material. Aerogel blanket compositions are particularly useful in applications requiring flexibility because they are highly conformable and can be used like a blanket to cover surfaces of simple or complex geometries while retaining the excellent thermal insulating properties of aerogel.

[0074] In the context of this disclosure, the terms "flexible" and "flexible" refer to an aerogel material or composition that can be bent or flexed without macrostructural failure. The aerogel compositions of the present disclosure can be bent at least 5°, at least 25°, at least 45°, at least 65°, or at least 85° without macroscopic failure, and / or have a bend radius of less than 4 feet, less than 2 feet, less than 1 foot, less than 6 inches, less than 3 inches, less than 2 inches, less than 1 inch, or less than ½ inch without macroscopic failure. Similarly, the terms "highly flexible" or "highly flexible" refer to an aerogel material or composition that can be bent to at least 90° without macroscopic failure and / or have a bend radius of less than ½ inch. Additionally, the terms "classified as flexible" and "classified as flexible" refer to an aerogel material or composition that can be classified as flexible according to ASTM C1101 (ASTM International, West Conshohocken, Pennsylvania).

[0075] Aerogel compositions of the present disclosure may be classified as flexible, highly flexible, and / or flexible. Aerogel compositions of the present disclosure may also be drapeable. In the context of this disclosure, the terms "drape" and "drapeable" refer to the ability of an aerogel material or composition to be bent or curved 90° or more through a radius of curvature of about 4 inches or less without macroscopic fracture. Aerogel materials or compositions according to certain embodiments of the present disclosure may be flexible so that the composition is non-rigid and can be applied and conformed to a three-dimensional surface or object, or may be preformed into various shapes and configurations to simplify installation or application.

[0076] In the context of this disclosure, the term "additive" or "additive element" refers to a material that can be added to an aerogel composition before, during, or after aerogel production. Additives can be added to modify or improve desirable properties of the aerogel or to counteract undesirable properties in the aerogel. Additives are typically added to the aerogel material either before gelation (to a precursor liquid), during gelation (to a transition-state material), or after gelation (to a solid or semi-solid material). 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, fire class additives, corrosion inhibitors, thermally conductive components, components with thermal capacitance, phase change materials, pH adjusters, redox modifiers, HCN mitigators, off-gassing mitigators, conductive compounds, dielectric compounds, magnetic compounds, radar-blocking components, hardeners, shrinkage inhibitors, and other aerogel additives known to those skilled in the art. In some embodiments, the component providing the thermal capacity can include a material having a specific heat capacity of at least about 0.3 J / (gC). In some embodiments, the material with thermal capacitance can include a specific heat capacity of at least about 0.5 J / (gC). For example, the material providing the thermal capacity can include a metal such as aluminum, titanium, nickel, steel, iron, or a combination thereof. In some embodiments, the thermal control element or battery thermal management element can include a layer or coating of a material with thermal capacitance. In some embodiments, the thermal control element or battery thermal management element can include particles of an electrically conductive material that provides thermal capacitance disposed within a layer of the thermal control element or battery thermal management element. In certain embodiments, the thermal control element or battery thermal management element can include at least one layer of a material with thermal capacitance disposed adjacent to the aerogel composition. In certain embodiments, the thermal control element or battery thermal management element can include at least one layer of a material with thermal capacitance disposed between at least two of the multiple layers of the aerogel composition.

[0077] In certain embodiments, the aerogel compositions, reinforced aerogel compositions, and thermal control or battery thermal management components disclosed herein can function during a high temperature event, for example, can provide thermal protection during a high temperature event disclosed herein. A high temperature event is a temperature event of at least about 1 cm over a period of at least 2 seconds. 2 at least about 25 kW / m over an area of 2 , at least about 30 kW / m 2 , at least about 35 kW / m 2 or at least about 40 kW / m 2 It is characterized by a sustained heat flux of approximately 40 kW / m 2 The heat flux of 10 cm is related to the heat flux resulting from a typical fire (Behavior of Charring Solids under Fire-Level Heat Fluxes; Milosavljevic, I., Suuberg, EM; NISTIR 5499; September 1994). In special cases, high temperature events may occur over a range of at least about 10 cm for a duration of at least 1 minute. 2 The heat flux is about 40 kW / m over an area of

[0078] In the context of this disclosure, the terms "thermal conductivity" and "TC" refer to a measure of a material or composition's ability to transfer heat between two surfaces on either side of the material or composition, where there is 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. It is typically expressed in mW / m * K (milliwatts / meter *The thermal conductivity of a material is reported in SI units as degrees Kelvin. The thermal conductivity of a material can be measured using a variety of methods, 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, Pennsylvania), 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, Pennsylvania), Test Method for Steady-State Heat Transfer Properties of Pipe Insulation (ASTM C335, ASTM International, West Conshohocken, Pennsylvania), Thin Heater Thermal Conductivity Test (ASTM C1114, ASTM International, West Conshohocken, Pennsylvania), and Standard Test Method for Thermal Transmission Properties of Thermally Conductive Electrical Insulation Materials (ASTM D5470, ASTM International, West Conshohocken, Pennsylvania). Conshohocken, Pennsylvania), Determination of thermal resistance by means of guarded hot plate and heat flow meter methods (EN 12667, British Standards Institution, UK), or Determination of steady-state thermal resistance and relatedThermal conductivity can be determined by test methods known in the art, including the use of a thermal conductivity measurement device (ISO 8203, International Organization for Standardization, Switzerland). Because different methods may yield different results, in the context of this disclosure, unless otherwise specified, it is understood that thermal conductivity measurements are taken in an ambient environment at atmospheric pressure, a temperature of about 37.5°C, and a compressive load of about 2 psi in accordance with ASTM C518 standard (Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus). Measurements reported according to ASTM C518 typically correlate well with any measurements made according to EN 12667 with any relevant adjustment for compressive load. In certain embodiments, the aerogel material or composition of the present disclosure has a thermal conductivity of 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 a range between any two of these values.

[0079] Thermal conductivity measurements can also be taken under compression, at atmospheric pressure, and at a temperature of about 10°C. Thermal conductivity measurements at 10°C are typically 0.5 to 0.7 mW / mK lower than corresponding thermal conductivity measurements at 37.5°C. In certain embodiments, aerogel materials or compositions of the present disclosure have a thermal conductivity at 10°C of 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 a range between any two of these values.

[0080] In the context of this disclosure, the term "density" refers to a measure of the mass per unit volume of an aerogel material or composition. The term "density" generally refers to the apparent density of an aerogel material as well as the bulk density of an aerogel composition. Density is typically measured in kg / m 3The density of an aerogel material or composition may be determined by methods known in the art, such as, but not limited to, 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), Determination of the apparent density of preformed pipe insulation (EN 13470, British Standards Institution, UK), or Determination of the apparent density of preformed pipe insulation (ISO 18098, International Organization for Standardization, Switzerland). Because different methods may yield different results, it is understood that in the context of this disclosure, density measurements are taken according to ASTM C 167 (Standard Test Method for Thickness and Density of Blanket or Batt Insulation) at 2 psi compression for thickness measurements unless otherwise specified. In certain embodiments, the aerogel material or composition of the present disclosure has 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, about 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 a range between any two of these values.

[0081] In the context of this disclosure, the term "hydrophobicity" refers to a measure of the ability of an aerogel material or composition to repel water.

[0082] The hydrophobicity of an aerogel material or composition can be expressed in terms of liquid water absorption. In the context of this disclosure, the term "liquid water absorption" refers to a measure of the ability of an aerogel material or composition to absorb or retain liquid water. Liquid water absorption can be expressed as the percentage of water (by weight or volume) absorbed or retained by the aerogel material or composition when exposed to liquid water under specific measurement conditions. The liquid water absorption of an aerogel material or composition can 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), and Thermal insulating products for building applications: Determination of short-term water absorption by partial immersion (EN 1609, British Standards Institution, UK). Because different methods may yield different results, it is understood that in the context of this disclosure, unless otherwise specified, liquid water absorption measurements are taken in accordance with ASTM C1511 (Standard Test Method for Determining the Water Retention (Repellency) Characteristics of Fibrous Glass Insulation) at ambient pressure and temperature.In certain embodiments, aerogel materials or compositions of the present disclosure can have a liquid absorption of about 50% by weight or less, about 40% by weight or less, about 30% by weight or less, about 20% by weight or less, about 15% by weight or less, about 10% by weight or less, about 8% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, about 0.1% by weight or less, or a range between any two of these values. An aerogel material or composition with improved liquid absorption compared to another aerogel material or composition has a lower percentage of liquid absorption / retention compared to a reference aerogel material or composition.

[0083] The hydrophobicity of an aerogel material or composition can be expressed in terms of water vapor uptake. In the context of this disclosure, the term "water vapor absorption" refers to a measurement of the potential of an aerogel material or composition to absorb water vapor. Water vapor absorption can be expressed as the percentage of water (by weight) absorbed or retained by the aerogel material or composition when exposed to water vapor under specific measurement conditions. Water vapor absorption of an aerogel material or composition can be determined by methods known in the art, including, but not limited to, Standard Test Method for Determining the Water Vapor Sorption of Unfaced Mineral Fiber Insulation (ASTM C1104, ASTM International, West Conshohocken, Pennsylvania) and Thermal insulating products for building applications: Determination of long-term water absorption by diffusion (EN 12088, British Standards Institution, UK). Because different methods may yield different results, it is understood that in the context of this disclosure, unless otherwise specified, water vapor absorption measurements are taken according to ASTM C1104 (Standard Test Method for Determining the Water Vapor Sorption of Unfaced Mineral Fiber Insulation) at ambient pressure, 49°C, and 95% humidity for 24 hours (modified from 96 hours according to ASTM C1104). In certain embodiments, the aerogel materials or compositions of the present disclosure can have a water vapor absorption of about 50% by weight or less, about 40% by weight or less, about 30% by weight or less, about 20% by weight or less, about 15% by weight or less, about 10% by weight or less, about 8% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, about 0.1% by weight or less, or a range between any two of these values.An aerogel material or composition that has improved water vapor absorption compared to another aerogel material or composition has a lower water vapor absorption / retention rate compared to a reference aerogel material or composition.

[0084] The hydrophobicity of an aerogel material or composition can be expressed by measuring the equilibrium contact angle of a water droplet at the interface with the surface of the material. The aerogel materials or compositions of the present disclosure can have a water contact angle of about 90° or greater, about 120° or greater, about 130° or greater, about 140° or greater, about 150° or greater, about 160° or greater, about 170° or greater, about 175° or greater, or a range between any two of these values.

[0085] In the context of this disclosure, the terms "heat of combustion," "HOC," and "ΔH CThe term "heat of combustion" refers to a measure of the amount of heat energy released in the combustion or exothermic pyrolysis of a material or composition. Heat of combustion is typically recorded as calories of heat energy released per gram of aerogel material or composition (cal / g) or as megajoules of heat energy released per kilogram of material or composition (MJ / kg). The heat of combustion of a material or composition can be determined by methods known in the art, including, but not limited to, Reaction to fire tests for products—Determination of the gross heat of combustion (calorific value) (EN ISO 1716, International Organization for Standardization, Switzerland, EN Adoption). In the context of this disclosure, heat of combustion measurements are taken in accordance with EN ISO 1716 standards (Reaction to fire tests for products—Determination of the gross heat of combustion (calorific value)) unless otherwise specified. In certain embodiments, aerogel compositions of the present disclosure can have a heat of combustion of about 750 cal / g or less, about 717 cal / g or less, about 700 cal / g or less, about 650 cal / g or less, about 600 cal / g or less, about 575 cal / g or less, about 550 cal / g or less, about 500 cal / g or less, about 450 cal / g or less, about 400 cal / g or less, about 350 cal / g or less, about 300 cal / g or less, about 250 cal / g or less, about 200 cal / g or less, about 150 cal / g or less, about 100 cal / g or less, about 50 cal / g or less, about 25 cal / g or less, about 10 cal / g or less, or a range between any two of these values. An aerogel composition having an improved heat of combustion compared to another aerogel composition has a lower heat of combustion value compared to a reference aerogel composition. In certain embodiments of the present disclosure, the HOC of an aerogel composite is improved by incorporating a fire class additive into the aerogel composite.

[0086] In the context of this disclosure, all thermal analyses and associated definitions refer to measurements performed starting at 25°C and ramping to 1000°C at a rate of 20°C / min in air at ambient pressure. Therefore, changes in any of these parameters must be taken into account (or re-run under these conditions) when measuring and calculating the onset of thermal decomposition, peak heat release temperature, peak sound absorption temperature, etc.

[0087] In the context of this disclosure, "onset of thermal decomposition" and "T D The term "onset of thermal decomposition" refers to a measurement of the lowest temperature of the heat of the environment at which a rapid exothermic reaction from the decomposition of the organic material appears within a material or composition. The onset of thermal decomposition of the organic material within a material or composition can be measured using thermogravimetric analysis (TGA). The TGA curve of a material indicates the weight loss (wt%) of the material when exposed to an elevated ambient temperature, thus indicating thermal decomposition. The onset of thermal decomposition of a material can be correlated to the intersection of the following tangents to the TGA curve: a line tangent to the baseline of the TGA curve, and a line tangent to the TGA curve at the point of maximum slope during the rapid exothermic decomposition event associated with the decomposition of the organic material. In the context of this disclosure, unless otherwise specified, measurements of the onset of thermal decomposition of an organic material are obtained using the TGA analysis presented in this paragraph.

[0088] The onset of thermal decomposition of a material can also be measured using differential scanning calorimetry (DSC) analysis. The DSC curve of a material shows the thermal energy (mW / mg) released by the material as it is exposed to a gradual increase in ambient temperature. The onset of thermal decomposition temperature of a material can be correlated to the point on the DSC curve where ΔmW / mg (change in thermal energy output) increases to a maximum, thus indicating heat generation from the aerogel material. In the context of this disclosure, measurements of the onset of thermal decomposition using DSC, TGA, or both are obtained using a temperature ramp rate of 20°C / min, as further defined in the previous paragraph, unless otherwise specified. DSC and TGA each provide similar values ​​for this onset of thermal decomposition, and often tests are performed simultaneously, resulting in results from both. In certain embodiments, the aerogel materials or compositions of the present disclosure have an onset of thermal decomposition of about 300°C or higher, about 320°C or higher, about 340°C or higher, about 360°C or higher, about 380°C or higher, about 400°C or higher, about 420°C or higher, about 440°C or higher, about 460°C or higher, about 480°C or higher, about 500°C or higher, about 550°C or higher, about 600°C or higher, or a range between any two of these values. In the context of this specification, for example, a first composition having an onset of thermal decomposition higher than the onset of thermal decomposition of a second composition is considered an improvement of the first composition over the second composition. In this specification, the onset of thermal decomposition of a composition or material is considered to be increased with the addition of one or more fire-class additives compared to a composition without any fire-class additives.

[0089] In the context of this disclosure, "endothermic decomposition onset" and "T EDThe term "onset of endothermic decomposition" refers to a measurement of the lowest temperature of the heat of the environment at which an endothermic reaction from decomposition or dehydration appears within a material or composition. The onset of endothermic decomposition of a material or composition can be measured using thermogravimetric analysis (TGA). The TGA curve of a material shows the weight loss (% by mass) of the material when exposed to an increasing ambient temperature. The onset of thermal decomposition of a material can be correlated to the intersection of a line tangent to the TGA curve, a line tangent to the baseline of the TGA curve, and a line tangent to the TGA curve at the point of maximum slope during the rapid endothermic decomposition or dehydration of the material. In the context of this disclosure, unless otherwise specified, measurements of the onset of endothermic decomposition of a material or composition are obtained using the TGA analysis presented in this paragraph.

[0090] In the context of this disclosure, the terms "furnace temperature rise" and "ΔT R The term "temperature" refers to the maximum temperature (T MAX ) and the baseline temperature (usually the final temperature, i.e., T FIN) furnace temperature rise is typically recorded in degrees Celsius or °C. The furnace temperature rise of a material or composition can be determined by methods known in the art, including, but not limited to, the Non-combustibility test (EN ISO 1182, International Organization for Standardization, Switzerland, EN Adoption). In the context of this disclosure, furnace temperature rise measurements are taken according to conditions comparable to the EN ISO 1182 standard (Reaction to fire tests for building and transport products: Non-combustibility test) unless otherwise specified. In certain embodiments, the aerogel compositions of the present disclosure can have an oven temperature rise of about 100°C or less, about 90°C or less, about 80°C or less, about 70°C or less, about 60°C or less, about 50°C or less, about 45°C or less, about 40°C or less, about 38°C or less, about 36°C or less, about 34°C or less, about 32°C or less, about 30°C or less, about 28°C or less, about 26°C or less, about 24°C or less, or a range between any two of these values. In the context of high temperature compositional stability, for example, a first composition having an oven temperature rise that is lower than the oven temperature rise of a second composition is considered an improvement of the first composition over the second composition. As used herein, the oven temperature rise of a composition is considered reduced when one or more fire-class additives are added compared to a composition without any fire-class additives.

[0091] In the context of this disclosure, the terms "flame time" and "T FLAMEThe term "sustained flame" refers to the measurement of a sustained flame of a material or composition under pyrolysis conditions, where a "sustained flame" is the persistence of a flame in any part of the visible portion of the sample lasting 5 seconds or more. Flame times are typically recorded in seconds or minutes. The flame time of a material or composition can be determined by methods known in the art, including, but not limited to, the Non-combustibility test (EN ISO 1182, International Organization for Standardization, Switzerland, EN Adoption). In the context of the present disclosure, flame time measurements are obtained according to conditions comparable to the EN ISO 1182 standard (Reaction to fire tests for building and transport products: Non-combustibility test) unless otherwise specified. In certain embodiments, the aerogel compositions of the present disclosure have a flame time of about 30 seconds or less, about 25 seconds or less, about 20 seconds or less, about 15 seconds or less, about 10 seconds or less, about 5 seconds or less, about 2 seconds or less, or a range between any two of these values. In the context of this specification, for example, a first composition having a flame time that is shorter than the flame time of a second composition is considered to be an improvement of the first composition relative to the second composition. In this specification, the flame time of a composition is considered to be reduced when one or more fire-class additives are added compared to a composition that does not include any fire-class additives.

[0092] In the context of this disclosure, the terms "mass loss" and "ΔM" refer to a measurement of the amount of a material, composition, or composite that is lost or burned off under pyrolysis conditions. Mass loss is typically reported as weight percent or wt%. The mass loss of a material, composition, or composite can be determined by methods known in the art, including, but not limited to, the Non-combustibility test (EN ISO 1182, International Organization for Standardization, Switzerland, EN Adoption). In the context of this disclosure, mass loss measurements are taken according to conditions comparable to the EN ISO 1182 standard (Reaction to fire tests for building and transport products: Non-combustibility test) unless otherwise specified. In certain embodiments, the aerogel compositions of the present disclosure can have a mass loss of about 50% or less, about 40% or less, about 30% or less, about 28% or less, about 26% or less, about 24% or less, about 22% or less, about 20% or less, about 18% or less, about 16% or less, or a range between any two of these values. In the context of this specification, for example, a first composition having a mass loss that is lower than the mass loss of a second composition is considered an improvement of the first composition relative to the second composition. In this specification, the mass loss of a composition is considered to be reduced when one or more fire-class additives are added, compared to a composition without any fire-class additives.

[0093] In the context of this disclosure, the term "peak heat release temperature" refers to the measured temperature of the heat of the environment at which the exothermic heat release from decomposition is greatest. The peak heat release temperature of a material or composition can be measured using TGA analysis, differential scanning calorimetry (DSC), or a combination thereof. DSC and TGA each provide similar values ​​for the temperature of peak heat release, and often the tests are performed simultaneously, resulting in results from both. In a typical DSC analysis, heat flow is plotted against increasing temperature, and the temperature of peak heat release is the temperature at which the highest peak occurs in such a curve. In the context of this disclosure, unless otherwise specified, the measured peak heat release temperature of a material or composition is obtained using the TGA analysis presented in this paragraph.

[0094] In the context of endothermic materials, the term "peak endotherm temperature" refers to the measured temperature of the heat of the environment at which the absorption of endothermic heat from decomposition is minimized. The peak endotherm temperature of a material or composition can be measured using TGA analysis, differential scanning calorimetry (DSC), or a combination thereof. In a typical DSC analysis, heat flow is plotted against increasing temperature, and the temperature of peak heat absorption is the temperature at which the lowest peak occurs in such a curve. In the context of this disclosure, unless otherwise specified, the measured peak heat absorption temperature of a material or composition is obtained using the TGA analysis presented in this paragraph.

[0095] In the context of this disclosure, the terms "low flammability" and "low combustibility" refer to a material or composition that meets a combination of the following properties: i) furnace temperature rise of 50°C or less, ii) flame time of 20 seconds or less, and iii) mass loss of 50 wt% or less. In the context of this disclosure, the terms "non-flammable" and "non-combustible" refer to a material or composition that meets a combination of the following properties: i) furnace temperature rise of 40°C or less, ii) flame time of 2 seconds or less, and iii) mass loss of 30 wt% or less. As described herein, it is contemplated that the flammability of a composition (e.g., the combination of furnace temperature rise, flame time, and mass loss) is reduced by including one or more fire class additives.

[0096] In the context of this disclosure, the terms "low flammability" and "low combustion" refer to a low-flammability material or composition having a total heat of combustion (HOC) of 3 MJ / kg or less. In the context of this disclosure, the terms "non-flammable" and "non-combustible" refer to a non-flammable material or composition having a heat of combustion (HOC) of 2 MJ / kg or less. It is contemplated that the HOC of a composition is reduced upon inclusion of one or more fire-class additives as described herein.

[0097] Aerogels are described as interconnected structural frameworks, most commonly composed of interconnected oligomeric, polymeric, or colloidal particles. Aerogel frameworks can be made from a range of precursor materials, including inorganic precursor materials (such as those used to make silica-based aerogels), organic precursor materials (such as those used to make carbon-based aerogels), hybrid inorganic / organic precursor materials, and combinations thereof. In the context of this disclosure, the term "amalgam aerogel" refers to an aerogel made from a combination of two or more different gel precursors, with the corresponding precursors referred to as "amalgam precursors."

[0098] Inorganic aerogels are generally formed from metal oxide or metal alkoxide materials. The metal oxide or metal alkoxide materials can be based on the oxide or alkoxide of any metal capable of forming an oxide. Such metals include, but are not limited to, silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium, cerium, and the like. Inorganic silica aerogels are traditionally made by the hydrolysis and condensation of silica-based alkoxides (such as tetraethoxysilane) or by the gelation of silicic acid or water glass. Other relevant inorganic precursor materials for silica-based aerogel synthesis include, but are not limited to, metal silicates such as sodium silicate or potassium silicate, alkoxysilanes, partially hydrolyzed alkoxysilanes, tetraethoxysilane (TEOS), partially hydrolyzed TEOS, condensation polymers of TEOS, tetramethoxysilane (TMOS), partially hydrolyzed TMOS, condensation polymers of TMOS, tetra-n-propoxysilane, partially hydrolyzed and / or condensation polymers of tetra-n-propoxysilane, polyethyl silicates, partially hydrolyzed polyethyl silicates, monomeric alkylalkoxysilanes, bis-trialkoxyalkyl or aryl silanes, polyhedral silsesquioxanes, or combinations thereof.

[0099] In certain embodiments of the present disclosure, pre-hydrolyzed TEOS, such as Silbond H-5 (SBH5, Silbond Corp), which is hydrolyzed to a water / silica ratio of about 1.9 to 2, may be used as commercially available or may be further hydrolyzed before incorporation into the gelation process. Partially hydrolyzed TEOS or TMOS, such as polyethyl silicate (Silbond 40) or polymethyl silicate, may also be used as commercially available or may be further hydrolyzed before incorporation into the gelation process.

[0100] Inorganic aerogels can also contain gel precursors containing at least one hydrophobic group, such as alkyl metal alkoxides, cycloalkyl metal alkoxides, and aryl metal alkoxides, which can impart or improve certain properties of the gel, such as stability and hydrophobicity. Inorganic silica aerogels can specifically contain hydrophobic precursors, such as alkyl silanes or aryl silanes. Hydrophobic gel precursors can be used as the primary precursor material to form the framework of the gel material. However, hydrophobic gel precursors are more commonly used as co-precursors in combination with simple metal alkoxides to form amalgam aerogels. Hydrophobic inorganic precursor materials for silica-based aerogel synthesis include, but are not limited to, trimethylmethoxysilane (TMS), dimethyldimethoxysilane (DMS), methyltrimethoxysilane (MTMS), trimethylethoxysilane, dimethyldiethoxysilane (DMDS), methyltriethoxysilane (MTES), ethyltriethoxysilane (ETES), diethyldiethoxysilane, dimethyldiethoxysilane (DMDES), ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane (PhTES), hexamethyldisilazane, and hexaethyldisilazane. Any derivatives of any of the above precursors may also be used, particularly certain polymers of other chemical groups may be added or crosslinked to one or more of the above precursors.

[0101] Aerogels may also be treated to impart or improve hydrophobicity. Hydrophobic treatments can be applied to sol-gel solutions, wet gels before liquid extraction, or aerogels after liquid extraction. Hydrophobic treatments are particularly common in the production of metal oxide aerogels, such as silica aerogels. Examples of hydrophobic treatments of gels are discussed in more detail below, specifically with respect to the treatment of silica gel wet gels. However, the specific examples and illustrations presented herein are not intended to limit the scope of the present disclosure to any particular type of hydrophobic treatment procedure or aerogel substrate. The present disclosure includes any gel or aerogel known to those skilled in the art, as well as related methods of hydrophobic treatment of aerogels, either in wet gel or dry aerogel form.

[0102] The hydrophobization treatment is carried out by reacting the functional groups of the hydrophobizing agent with the hydroxy moieties on the gel, such as silanol groups (Si-OH) present in the silica gel backbone. The resulting reaction converts the silanol groups and the hydrophobizing agent into hydrophobic groups in the silica gel backbone. The hydrophobizing agent compound reacts with the following reaction: R N MX 4-N (Hydrophobizing agent) + MOH (silanol) → MOMR N The hydrophobic group +HX can react with the hydroxyl groups of the gel. The hydrophobic treatment can be carried out on both the outer macroscopic surface of the silica gel and the inner pore surface within the porous network of the gel.

[0103] The gel can be immersed in a mixture of a hydrophobizing agent and any hydrophobic treatment solvent in which the hydrophobizing agent is soluble and which is miscible with the gel solvent in the wet gel. A wide range of hydrophobic treatment solvents can be used, including solvents such as methanol, ethanol, isopropanol, xylene, toluene, benzene, dimethylformamide, and hexane. The hydrophobizing agent in liquid or gas form can also be directly contacted with the gel to impart hydrophobicity.

[0104] The hydrophobic treatment process can include mixing or agitation to help the hydrophobizing agent penetrate the wet gel. The hydrophobic treatment process can also include varying other conditions, such as temperature and pH, to further enhance and optimize the treatment reaction. After the reaction is complete, the wet gel is washed to remove unreacted compounds and reaction by-products.

[0105] The hydrophobizing agent for the hydrophobic treatment of aerogels is generally represented by the formula R N MX 4-N where M is a metal, R is a hydrophobic group such as CH3, CH2CH3, CH6, or a similar hydrophobic alkyl, cycloalkyl, or aryl moiety, and X is a halogen, usually Cl. Specific examples of hydrophobizing agents include, but are not limited to, trimethylchlorosilane (TMCS), triethylchlorosilane (TECS), triphenylchlorosilane (TPCS), dimethylchlorosilane (DMCS), dimethyldichlorosilane (DMDCS), and the like. The hydrophobizing agent may be of the formula: Y(RM)2, where M is a metal, Y is a bridging group such as NH or O, and R is a hydrophobic group such as CH3, CH2CH3, CH6, or a similar hydrophobic alkyl, cycloalkyl, or aryl moiety. Specific examples of such hydrophobizing agents include, but are not limited to, hexamethyldisilazane [HMDZ] and hexamethyldisiloxane [HMDSO]. The hydrophobizing agent may be of the formula R N Music Video 4-N where V is a reactive or leaving group other than halogen. Specific examples of such hydrophobizing agents include, but are not limited to, vinyltriethoxysilane and vinyltrimethoxysilane.

[0106] The hydrophobic treatment of the present disclosure may also be carried out during liquid removal, exchange, or drying of the gel. In certain embodiments, the hydrophobic treatment may be carried out in a supercritical fluid environment (e.g., but not limited to, supercritical carbon dioxide) and may be combined with a drying or extraction step.

[0107] In the context of this disclosure, the term "hydrophobically bonded silicon" refers to silicon atoms within the framework of a gel or aerogel that contain at least one hydrophobic group covalently bonded to the silicon atom. Examples of hydrophobically bonded silicon include, but are not limited to, silicon atoms of silica groups within a gel framework formed from a gel precursor containing at least one hydrophobic group (such as MTES or DMDS). Hydrophobically bonded silicon can also include, but is not limited to, silicon atoms within the gel framework or on the surface of the gel, which have been treated with a hydrophobizing agent (such as HMDZ) to impart or improve hydrophobicity by incorporating additional hydrophobic groups into the composition. Hydrophobic groups in this disclosure include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertbutyl, octyl, phenyl, or other substituted or unsubstituted hydrophobic organic groups known to those skilled in the art. In the context of this disclosure, the terms "hydrophobic group," "hydrophobic organic material," and "hydrophobic organic content" specifically exclude readily hydrolyzable organosilicon-bonded alkoxy groups in the backbone of the gel material, which are the product of the reaction between organic solvents and silanol groups. Such excluded groups can be distinguished from the hydrophobic organic content thereof by NMR analysis. The amount of hydrophobically bonded silicon in the aerogel can be determined by CP / MAS. 29 Aerogels can be analyzed using NMR spectroscopy, such as Si solid-state NMR. NMR analysis of aerogels allows for the characterization and relative quantification of M-type hydrophobic bonded silicon (monofunctional silica such as TMS derivatives), D-type hydrophobic bonded silicon (difunctional silica such as DMDS derivatives), T-type hydrophobic bonded silicon (trifunctional silica such as MTES derivatives), and Q-type silicon (tetrafunctional silica such as TEOS derivatives). NMR analysis also allows for the classification of specific types of hydrophobic bonded silicon into subtypes (e.g., T of T-type hydrophobic bonded silicon). 1 seeds, T 2 species and T 3NMR analysis of silica materials can be used to analyze the bonding chemistry of hydrophobically bonded silicon in aerogels by enabling the classification of silica into species. Specific details regarding NMR analysis of silica materials can be found in the article by Geppi et al., "Applications of Solid-State NMR to the Study of Organic / Inorganic Multicomponent Materials," Appl. Spec. Rev. (2008), 44-1:1-89, specifically pages 7 to 9, which is incorporated herein by reference according to the specifically cited pages.

[0108] CP / MAS 29 The characterization of hydrophobic bond silicon in Si NMR analysis is based on the following chemical shift peaks: M 1 (30 to 10 ppm), D 1 (10 to -10 ppm), D 2 (-10 to -20 ppm), T 1 (-30 to -40 ppm), T 2 (-40 to -50 ppm), T 3 (-50 to -70 ppm), Q 2 (-70 to -85 ppm), Q 3 (-85 to -95 ppm), Q 4 (-95 to -110 ppm). These chemical shift peaks are approximate and illustrative and are not intended to be limiting or definitive. The exact chemical shift peaks attributed to various silicon species within a material may depend on the specific chemical components of the material and can generally be deciphered by routine experimentation and analysis by those skilled in the art.

[0109] In the context of this disclosure, the terms "hydrophobic organic content" or "hydrophobic content" or "hydrophobic content" refer to the amount of hydrophobic organic material attached to the framework of an aerogel material or composition. The hydrophobic organic content of an aerogel material or composition can be expressed as a weight percentage of the amount of hydrophobic organic material in the aerogel framework relative to the total amount of material in the aerogel material or composition. The hydrophobic organic content can be calculated by one skilled in the art based on the nature and relative concentrations of the materials used to make the aerogel material or composition. The hydrophobic organic content can also be measured using thermogravimetric analysis (TGA) of the material in question, preferably in an oxygen atmosphere (although TGA in an alternative gas environment is also useful). Specifically, the percentage of hydrophobic organic material in an aerogel can be correlated with the rate of weight loss of the hydrophobic aerogel material or composition when exposed to the temperature of combustion heat during TGA analysis, with adjustments made for loss of water, loss of residual solvent, and loss of readily hydrolyzable alkoxy groups during TGA analysis. Other alternative techniques, such as differential scanning calorimetry, elemental analysis (especially carbon), chromatographic techniques, nuclear magnetic resonance spectroscopy, and other analytical techniques known to those skilled in the art, can be used to measure and determine the hydrophobe content of the aerogel compositions of the present disclosure. In certain cases, a combination of known techniques may be useful or necessary to determine the hydrophobe content of the aerogel compositions of the present disclosure.

[0110] The aerogel materials or compositions of the present disclosure can have a hydrophobic organic content of 50% by weight or less, 40% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 8% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or a range between any two of these values.

[0111] The term "fuel content" refers to the total amount of combustible material in an aerogel material or composition, which can be correlated to the total percentage weight loss of the aerogel material or composition when exposed to flammable thermal temperatures during TGA or TG-DSC analysis, with an adjustment made for water loss. The fuel content of an aerogel material or composition can include hydrophobic organic content, as well as other flammable residual alcoholic solvents, filler materials, reinforcing materials, and readily hydrolyzable alkoxy groups.

[0112] Organic aerogels are generally formed from carbon-based polymer precursors. Such polymeric materials include, but are not limited to, resorcinol-formaldehyde (RF), polyimides, polyacrylates, polymethyl methacrylates, acrylate oligomers, polyoxyalkylenes, polyurethanes, polyphenols, polybutadiene, trialkoxysilyl-terminated polydimethylsiloxanes, polystyrenes, polyacrylonitriles, polyfurfural, melamine-formaldehyde, cresol-formaldehyde, phenol-furfural, polyethers, polyols, polyisocyanates, polyhydroxybenzaldehyde, polyvinyl alcohol dialdehyde, polycyanurates, polyacrylamides, various epoxies, agar, agarose, chitosan, and combinations thereof. As an example, organic RF aerogels are typically made from the sol-gel polymerization of resorcinol or melamine with formaldehyde under alkaline conditions.

[0113] Organic / inorganic hybrid aerogels are primarily composed of organically modified silica ("ormosil") aerogels. These ormosil materials contain organic components covalently bonded to a silica network. They are typically formed by the hydrolysis and condensation of an organically modified silane, R-Si(OX)3, with a conventional alkoxide precursor, Y(OX)4. In these formulas, X can represent, for example, CH3, CH5, CH3H7, or CH9; Y can represent, for example, Si, Ti, Zr, or Al; and R can be any organic fragment, such as methyl, ethyl, propyl, butyl, isopropyl, methacrylate, acrylate, vinyl, or epoxide. The organic components of ormosil aerogels can be dispersed throughout the silica network or chemically bonded to it.

[0114] In the context of this disclosure, the term "ormosil" encompasses the aforementioned materials as well as other organically modified materials, sometimes referred to as "ormocurs." Ormosils are often used as coatings, for example, by sol-gel processes to cast an ormosil film onto a substrate material. Examples of other organic-inorganic hybrid aerogels of the present disclosure include, but are not limited to, silica polyethers, silica-PMMA, silica-chitosan, carbides, nitrides, and other combinations of the aforementioned organic and inorganic aerogel-forming compounds. Published U.S. Patent Application Publication No. 20050192367 (paragraphs

[0022] to

[0038] and

[0044] to

[0058] ) contains teachings of such hybrid organic-inorganic materials and is incorporated herein by reference according to the individually cited sections and paragraphs.

[0115] In certain embodiments, the aerogels of the present disclosure are primarily inorganic silica aerogels formed from prepolymerized silica precursors, preferably as oligomers, or hydrolyzed silicate esters formed from silicon alkoxides in alcohol solvents. In certain embodiments, such prepolymerized silica precursors or hydrolyzed silicate esters may be formed in situ from other precursors or silicate esters, such as alkoxysilanes or water glass. However, the present disclosure as a whole may be practiced with any other aerogel compositions known to those skilled in the art and is not limited to any one precursor material or amalgamated mixture of precursor materials.

[0116] As described above, aerogel compositions according to embodiments of the present disclosure offer favorable properties for compressibility, compressive resilience, and compliance. When used as separators between cells in a battery module, insulation sheets formed using the aerogel compositions can provide resistance to compressive deformation to accommodate cell expansion due to active material decomposition and swelling during battery charge / discharge cycles. During initial assembly of the battery module, a relatively low load of 1 MPa or less is typically applied to the cell separator material, such as the reinforced aerogel composition disclosed herein. As the cells in the battery module expand or swell during charge / discharge cycles, loads of up to about 5 MPa can be applied to the cell separator material, such as the reinforced aerogel composition disclosed herein. Therefore, the compressibility, compressive resilience, and compliance of the cell separator material are important properties.

[0117] In other embodiments, the battery thermal management component can include other thermal protection layers, either separately or in combination with the aerogel composition. For example, the thermal protection layer can include a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof. In some embodiments, the thermal protection layer can include, for example, a mica board containing at least 80% mica. In some embodiments, the thermal protection layer can include an inorganic ceramic paper made from refractory ceramic fibers.

[0118] In exemplary aspects, the present disclosure provides a thermal control element or battery thermal management element that exhibits a compressibility of less than about 25% at about 25 kPa. In some embodiments, the compressive force deflection can be 5 to 500 kPa, or 5 to 80 kPa, at 25% deflection. The compressive force deflection can be 100 to 500 kPa, or 200 to 300 kPa, at 75% deflection. Optionally, upon release of compression, the thermal control element or battery thermal management element can have sufficient elasticity to return to at least about 80%, 75%, 65%, 60%, or 50% of its original thickness. In some embodiments, the thermal control element or battery thermal management element exhibits a compressibility of less than about 25% in the range of about 25 kPa to about 35 kPa, preferably less than about 50% at about 50 kPa. In some embodiments, the thermal control member or battery thermal management member exhibits a compressibility ranging from about 25% to about 50% at about 50 kPa. In exemplary embodiments, the thermal control member or battery thermal management member exhibits a compressibility of less than about 80% at about 245 kPa, e.g., less than about 70% at about 235 kPa. In exemplary embodiments, the thermal control member or battery thermal management member exhibits a compressibility of less than about 70% at about 345 kPa. The thermal conductivity of the thermal control member or battery thermal management member is preferably maintained at less than about 60 mW / mK, less than about 50 mW / mK, about 40 mW / mK, about 30 mW / mK, about 25 mW / mK, or a range between these values ​​when the thermal control member or battery thermal management member is compressed.

[0119] As described above, aerogel compositions according to embodiments of the present disclosure can include an aerogel skeleton containing macropores. Without being bound by any particular theory of operation, the presence of macropores within the aerogel skeleton can maintain or even improve thermal properties, such as reducing thermal conductivity, while allowing the aerogel composition, e.g., a reinforced aerogel composition, to be compressed. For example, the macropores can be deformed, crushed, or otherwise reduced in size by compressing the composition, thereby reducing the thickness of the composition under load. However, as the macropores deform, they effectively become smaller pores. As a result, the pathways for heat transfer within the aerogel skeleton can become more tortuous as the macropores deform, thereby improving thermal properties, e.g., reducing thermal conductivity. In the context of the present disclosure, "mesopores" are pores with an average pore diameter in the range of about 2 nm to about 50 nm. Aerogel skeletons are typically mesoporous (i.e., primarily contain pores with an average diameter in the range of about 2 nm to about 50 nm). In certain embodiments, the aerogel skeleton of the aerogel compositions of the present disclosure can contain macropores. In the context of this disclosure, "macropores" are pores with an average pore diameter greater than about 50 nm. The aerogel skeleton can contain both macropores and mesopores. For example, at least 10% of the pore volume of the aerogel skeleton can be composed of macropores, at least 5% of the pore volume of the aerogel skeleton can be composed of macropores, at least 75% of the pore volume of the aerogel skeleton can be composed of macropores, at least 95% of the pore volume of the aerogel skeleton can be composed of macropores, or 100% of the pore volume of the aerogel skeleton can be composed of macropores. In some specific embodiments, the aerogel skeleton can be a macroporous aerogel skeleton, such that a majority of its pore volume is composed of macropores. In some examples, the macroporous aerogel skeleton can also contain micropores and / or mesopores.In some embodiments, the average pore size (diameter) of the pores in the aerogel framework can be greater than 50 nm, 50 to 5000 nm, 250 to 2000 nm, 500 to 2000 nm, 500 to 1400 nm, or greater than 1200 nm. In certain embodiments, the average pore size can be greater than 50 nm, 50 to 1000 nm, preferably 100 to 800 nm, and more preferably 250 to 750 nm in diameter.

[0120] In some embodiments, the variation in pore size within the aerogel framework can be uniformly distributed throughout the aerogel framework, e.g., the average pore size can be substantially the same throughout the aerogel framework.

[0121] In other embodiments, the pore size variation within the aerogel skeleton can be distributed non-uniformly throughout the aerogel skeleton. For example, the average pore size can be different in certain regions of the aerogel skeleton. In some exemplary embodiments, the average pore size can be larger at the top surface, the bottom surface, or both the top and bottom surfaces of the aerogel skeleton. For example, the macropores can be distributed within the composition such that the ratio of macropores to mesopores is greater at the top surface than the bottom surface, greater at the bottom surface than the top surface, or greater at both the top and bottom surfaces than the central region between the top and bottom surfaces. In another example, the macropores can be distributed within the composition such that the ratio of macropores to mesopores is greater near the top surface than near the bottom surface, greater near the top surface than near the bottom surface, or greater near both the top and bottom surfaces than the central region between the top and bottom surfaces. In other embodiments, the average pore size can be larger in the intermediate region between the top and bottom surfaces of the aerogel skeleton.

[0122] Macropores can be formed during the preparation of an aerogel composition. For example, macropore formation can be induced in a gel precursor material during its transition to a gel composition. In some embodiments, macropore formation can be achieved by, for example, inducing spinodal decomposition of a gel precursor solution. In another example, macropore formation can be induced by the addition of one or more foaming agents.

[0123] The macropores present in the resulting aerogel framework can be created by selecting processing conditions that favor the formation of macropores versus mesopores and / or micropores. The amount of macropores can be adjusted by adjusting any one, any combination, or all of the following variables: (1) polymerization solvent, (2) polymerization temperature, (3) polymer molecular weight, (4) molecular weight distribution, (5) copolymer composition, (6) amount of branching, (7) amount of crosslinking, (8) branching method, (9) method of crosslinking, (10) method used to form the gel, (11) type of catalyst used to form the gel, (12) chemical composition of the catalyst used to form the gel, (13) amount of catalyst used to form the gel, (14) gel formation temperature, (15) type of gas flowing over the material during gel formation, (16) velocity of gas flowing over the material during gel formation, (17) atmospheric pressure during gel formation, (18) removal of dissolved gas during gel formation, (19) presence of solid additives in the resin during gel formation, (20) duration of the gel formation process, (21) substrate used in gel formation, (22) type of solvent used at each step of the solvent exchange process, and (23) solvent exchange. (24) the composition of the solvent used at each step of the process, (25) the residence time of the part at each step of the solvent exchange process, (26) the flow rate of the solvent exchange solvent, (27) the type of solvent exchange solvent flow, (28) the agitation rate of the solvent exchange solvent, (29) the temperature used at each step of the solvent exchange process, (30) the ratio of the volume of the solvent exchange solvent to the volume of the part, (31) the drying method, (32) the temperature at each step of the drying process, (33) the pressure at each step of the drying process, (34) the composition of the gas used at each step of the drying process, (35) the gas flow rate at each step of the drying process, (36) the temperature of the gas at each step of the drying process, (37) the temperature of the part at each step of the drying process, (38) the presence of an enclosure around the part at each step of the drying process, (39) the type of enclosure that surrounds the part during drying, and / or (40) the solvent used at each step of the drying process. The polyfunctional amine and diamine compounds can be added as solids, neat or dissolved in a suitable solvent, separately or together in one or more portions.In another embodiment, a method for producing an aerogel can include the steps of: (a) providing a polyfunctional amine compound and at least one diamine compound in a solvent to form a solution; (b) providing at least one dianhydride compound to the solution of step (a) under conditions sufficient to form a branched polymer matrix solution, wherein the branched polymer matrix is ​​solubilized in the solution; and (c) subjecting the branched polymer matrix solution to conditions sufficient to form an aerogel having an open-cell structure. Macropores present in the resulting aerogel framework can be formed by the methods described above. In one preferred, non-limiting embodiment, the formation of macropores versus smaller mesopores and micropores can be primarily controlled by controlling the polymer / solvent dynamics during gel formation.

[0124] As described above, aerogel compositions according to embodiments of the present disclosure can include an aerogel skeleton and a reinforcing material, at least a portion of which is free of aerogel. For example, the aerogel skeleton can extend partially through the thickness of the reinforcing material. In such embodiments, some of the reinforcing material, such as OCMF, fibers, or a combination thereof, can include aerogel material and some can be free of aerogel. For example, in some embodiments, the aerogel extends through about 90% of the thickness of the reinforcing material, between about 50% and about 90% of the thickness of the reinforcing material, between about 10% and about 50% of the thickness of the reinforcing material, or about 10% of the thickness of the reinforcing material.

[0125] Without being bound by any particular theory of operation, aerogel compositions in which at least a portion of the reinforcing material does not contain aerogel can impart desirable properties for compressibility, compressibility, and compliance. For example, the properties of the reinforcing material can be selected to provide sufficient reinforcement and support for thermal properties in the aerogel-containing regions, and sufficient compressibility, compressibility, and / or compliance in the aerogel-free regions. The aerogel-containing portion of the reinforced aerogel composition can have a desired thermal conductivity, e.g., about 25 mW / m *Although the K can be less than 0.1, the portion of the reinforcement that does not contain aerogel can impart or improve a desired physical property, such as compressibility.

[0126] In some embodiments, reinforced aerogel compositions in which at least a portion of the reinforcing material is free of aerogel can be formed using the methods disclosed herein by combining the reinforcing material with a sufficient amount of precursor solution to partially fill it with the precursor solution. For example, the volume of the precursor can be less than the volume of the reinforcing material such that the precursor only partially penetrates the reinforcing material. Upon drying, the resulting reinforced aerogel composition comprises an aerogel skeleton that extends less than the entire thickness of the reinforcing material, as described above. In other embodiments, reinforced aerogel compositions in which at least a portion of the reinforcing material is free of aerogel can be formed by removing a surface aerogel layer from the reinforced aerogel composition.

[0127] In some embodiments, reinforced aerogel compositions, in which at least a portion of the reinforcing material does not contain aerogel, can be formed using a reinforcing material with mixed properties throughout the thickness of the reinforcing material. For example, the reinforcing material can include multiple layers, each with different properties, such as average pore / cell size, material composition, closed-cell, open-cell, surface treatment, or a combination thereof. The multiple layers can be bonded to each other, for example, using an adhesive, by flame bonding, or by other suitable methods or mechanisms as discussed herein. The different properties of the reinforcing material can provide different distributions of aerogel through the layers. For example, the open-cell portion of the reinforcing material can contain an aerogel framework, while the closed-cell portion remains substantially free of aerogel. Similarly, other material properties of the reinforcing material or its layers can determine the distribution of aerogel within the reinforcing material and, therefore, within the reinforced aerogel composition.

[0128] In some exemplary embodiments, reinforced aerogel compositions can be formed using the methods disclosed herein, in which at least a portion of the reinforcing material does not contain aerogel, and the properties of the reinforcing material or layer or layers control or influence the amount of precursor solution that fills that material or layer, e.g., during a casting process, thereby partially filling the reinforcing material with precursor solution. For example, one layer of the reinforcing material can have open cells, while another layer of the reinforcing material can have closed cells. When the precursor solution is combined with such a reinforcing agent, the gel precursor solution can penetrate the open cells of that layer without substantially penetrating the closed cells of other layers. When such a composition is dried, the resulting reinforced aerogel composition can include a portion that does not contain aerogel, e.g., a closed-cell layer, while another portion, e.g., an open-cell layer, contains aerogel.

[0129] In some embodiments, the additives disclosed herein (e.g., heat-absorbing additives, opacifying additives, fire-class additives, or other additives) can be non-uniformly dispersed within the reinforced aerogel composition. For example, the additive material can vary through the thickness of the aerogel composition or along the length and / or width of the aerogel composition. For example, the additive can be accumulated on one side of the aerogel composition. In some embodiments, the additive material can be concentrated in one layer of the aerogel composite or provided as a separate layer consisting essentially of the additive adjacent to or attached to the composite. For example, a thermal control element or battery thermal management element can include a layer consisting essentially of a heat-absorbing material such as gypsum, sodium bicarbonate, or magnesia-based cement. In further exemplary embodiments, the aerogel composition can also include at least one layer of an additional material within the composition or as a facing layer. For example, the layer can be a layer selected from the group consisting of a polymer sheet, a metal sheet, a fiber sheet, a highly oriented graphite material, such as a pyrolytic graphite sheet, and a woven fabric sheet. In some embodiments, the facing layer can be attached to the composition by an adhesive mechanism selected from the group consisting of, for example, aerosol adhesives, urethane-based adhesives, acrylate adhesives, hot melt adhesives, epoxies, rubber-resin adhesives, polyurethane composite adhesives, and combinations thereof. In some embodiments, the facing layer can be attached to the composition by a non-adhesive mechanism selected from the group consisting of, for example, flame gluing, needling, stitching, sealing bags, rivets, buttons, clamps, wraps, braces, and combinations thereof. In some embodiments, the facing layer can be attached to the composition using any combination of the above-mentioned adhesive and non-adhesive mechanisms.

[0130] As discussed herein, an aerogel composition or composite can include a material that combines aerogel particulates, particles, granules, beads, or powder with a binder, such as an adhesive, resin, cement, foam, polymer, or similar solid or solidifying material, to incorporate them into a solid or semi-solid material. For example, an aerogel composition can include a reinforcing material, aerogel particles, and optionally a binder. In an exemplary embodiment, a slurry containing aerogel particles and at least one wetting agent can be provided. For example, the aerogel particles can be coated or wetted with at least one wetting agent, such as a surfactant or dispersant. The aerogel particles can be fully wetted, partially wetted (e.g., surface-wetted), or present in a slurry. Preferred wetting agents can be volatilized to allow for proper restoration of the hydrophobicity of hydrophobic aerogel particles. If the wetting agent remains on the surface of the aerogel particles, the remaining wetting agent can contribute to the overall thermal conductivity of the composite. Therefore, preferred wetting agents are those that are removable, such as by volatilization, with or without decomposition or other means. Generally, any wetting agent compatible with aerogel can be used.

[0131] Wetting agent-coated slurries or aerogels can be useful as a method for easily incorporating hydrophobic aerogels into various materials, such as other aqueous-containing fluids, slurries, adhesives, and binder materials, which can optionally be cured to form solid materials, fibers, metallized fibers, discrete fibers, woven materials, nonwoven materials, needled nonwovens, battings, webs, mats, felts, and combinations thereof. Slurries containing aerogels wetted with or containing at least one wetting agent allow for easy incorporation and uniform distribution of the hydrophobic aerogel. Wet processes, such as those described in U.S. Pat. Nos. 9,399,864, 8,021,583, 7,635,411, and 5,399,422 (each of which is incorporated herein by reference in its entirety), use aqueous slurries to disperse aerogel particles, fibers, and other additives. The slurry can then be dewatered to form a layer of aerogel particles, fibers, and additives, dried, and optionally calendered to produce an aerogel composite.

[0132] In other embodiments, the aerogel composition can include aerogel particles, at least one inorganic matrix material, and optionally fibers, auxiliary materials, additives, and additional inorganic binders. The inorganic matrix material, in some embodiments, can include a phyllosilicate, such as a naturally occurring phyllosilicate, such as kaolin, clay, or bentonite, a synthetic phyllosilicate, such as magadiite or Kenyaite, or a mixture thereof. The phyllosilicate can be calcined or uncalcined, for example, to dry the material and release water of crystallization. The inorganic matrix material, in some embodiments, can also include an inorganic binder, such as cement, lime, gypsum, or a suitable mixture thereof, in combination with the phyllosilicate. The inorganic matrix material, in some embodiments, can also include other inorganic additives disclosed herein, such as fire-glass additives, opacifiers, or combinations thereof. Exemplary methods and aerogel compositions including inorganic matrix materials are disclosed in U.S. Patent Nos. 6,143,400 and 6,083,619, each of which is incorporated herein by reference in its entirety. In some embodiments, the aerogel composition can include aerogel particles coated or absorbed onto woven materials, nonwoven materials, needled nonwovens, battings, webs, mats, felts, and combinations thereof. An adhesive binder can be included in the composition. Additives such as fire class additives, opacifiers, or combinations thereof, as disclosed herein, can also be included. Exemplary methods and aerogel compositions coated on or absorbed into fabrics are disclosed in U.S. Patent Application Publication No. 2019 / 0264381, which is incorporated herein by reference in its entirety.

[0133] As discussed herein, aerogel composites can be laminated or faced with other materials, such as reinforcing layers of opposing materials. In one embodiment, the present disclosure provides a multilayer laminate including at least one base layer comprising a reinforced aerogel composition and at least one facing layer. In one embodiment, the facing layer includes a reinforcing material. In one embodiment, the reinforced aerogel composition is reinforced with a fiber-reinforced layer or an open-cell foam-reinforced layer. In one embodiment, the present disclosure provides a multilayer laminate including a base layer comprising a reinforced aerogel composition and at least two facing layers including a reinforcing material, the two facing layers being on opposite surfaces of the base layer. For example, multilayer aerogel laminate composites can be made according to the methods and materials described in U.S. Patent Application Publication No. 2007 / 0173157.

[0134] The facing layer can include a material that helps impart certain properties to the final composite structure, such as improved flexibility or reduced dusting. The facing material can be rigid or flexible. The facing material can include a conductive layer or a reflective foil. For example, the facing material can include a metal or metallized material. The facing material can include a nonwoven material. The facing layer can be disposed on a surface of the composite structure or a reinforced aerogel composite forming the composite structure, such as a thermal control element or a battery thermal management element. The facing layer can form a continuous coating or bag around the composite structure or a reinforced aerogel composite forming the composite structure, such as a thermal control element or a battery thermal management element. In some embodiments, one or more facing layers can encapsulate the composite structure or the reinforced aerogel composite forming the composite structure.

[0135] In one embodiment, the facing layer includes a polymer sheet surrounding the composite structure, more specifically a polymeric material including polyester, polyethylene, polyurethane, polypropylene, polyacrylonitrile, polyamide, aramid, more specifically a polymer such as polyethylene terephthalate, low density polyethylene, ethylene-propylene copolymer, poly(4-methyl-pentane), polytetrafluoroethylene, poly(1-butene), polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinyl acrylonitrile, polymethyl methacrylate, polyoxymethylene, polyphenylene sulfone, cellulose acetate, polycarbonate, polyethylene naphthalate, polycaprolactam, polyhexamethylene adipamide, polyundecanoamide, polyimide, or a combination thereof. In one embodiment, the polymer sheet comprises or consists essentially of an expanded polymer material, more specifically, an expanded polymer material including PTFE (ePTFE), expanded polypropylene (ePP), expanded polyethylene (ePE), expanded polystyrene (ePS), or a combination thereof. In a preferred embodiment, the opposing material consists essentially of an expanded polymer material. In one embodiment, the polymer sheet comprises or consists essentially of a microporous polymer material characterized by pore sizes ranging from 0.1 μm to 210 μm, 0.1 μm to 115 μm, 0.1 μm to 15 μm, or 0.1 μm to 0.6 μm.

[0136] In one embodiment, the facing layer material comprises or consists essentially of a fluoropolymer material. In the context of this disclosure, the terms "fluoropolymer" or "fluoropolymer material" refer to a material primarily composed of polymeric fluorocarbons. Suitable fluoropolymer facing layer materials include, but are not limited to, polytetrafluoroethylene (PTFE), including microporous PTFE, as described in U.S. Pat. No. 5,814,405, and expanded PTFE (ePTFE), such as Gore-Tex® (available from WL Gore), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polychlorotrifluoroethylene (PCTFE), ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), ethylene chlorotrifluoroethylene (ECTFE), and combinations thereof. In a preferred embodiment, the facing material consists essentially of a fluoropolymer material. In one preferred embodiment, the opposing material consists essentially of expanded PTFE (ePTFE) material.

[0137] In one embodiment, the facing layer material comprises or consists essentially of a non-fluoropolymer material. In the context of this disclosure, the terms "non-fluoropolymer" or "non-fluoropolymer material" refer to a material that does not contain a fluoropolymer material. Suitable non-fluoropolymer facing layer materials include, but are not limited to, aluminized Mylar, low-density polyethylene such as Tyvek® (available from DuPont), rubber or rubber composites, nonwoven materials, elastic fibers such as spandex, nylon, Lycra, or elastane, and combinations thereof. In one embodiment, the facing material is a flexible facing material.

[0138] In some embodiments, facing layer materials can include automotive resins and polymers, such as those having a maximum use temperature of up to about 100° C., up to about 120° C., or up to about 150° C. For example, facing layer materials can include acrylonitrile butadiene styrene (ABS) polycarbonate ABS, polypropylene, polyurethane, polystyrene, polyethylene, polycarbonate, polyimide, PVC, or combinations thereof. For example, aerogel composites and thermal control or battery thermal management members according to embodiments disclosed herein can include a layer of automotive resin or automotive polymer, a metal or metallized layer, and an aerogel layer.

[0139] The facing layer can be attached to the base layer by using an adhesive suitable for securing the inorganic or organic facing material to the reinforcing material of the base layer. Examples of adhesives that can be used in the present disclosure include, but are not limited to, cement-based adhesives, sodium silicate, latex, pressure-sensitive adhesives, silicone, polystyrene, aerosol adhesives, urethane, acrylate adhesives, hot melt adhesive systems, adhesive systems commercially available from 3M, epoxies, rubber resin adhesives, and polyurethane adhesive mixtures such as those described in U.S. Pat. No. 4,532,316.

[0140] The facing layer can also be attached to the base layer by using a suitable non-adhesive material or technique to secure the inorganic or organic facing material to the base layer reinforcing material. Examples of non-adhesive materials or techniques that can be used in the present disclosure include, but are not limited to, heat sealing, ultrasonic stitching, RF sealing, stitching or threading, needling, sealing bags, rivets or buttons, clamps, wraps, or other non-adhesive laminating materials.

[0141] The facing layer can be attached to the base layer at any stage in the manufacture of the aerogel composite. In one embodiment, the facing layer is attached to the base layer after the sol-gel solution is infused into the base reinforcing material but before gelation. In another embodiment, the facing layer is adhered to the base layer after the sol-gel solution is infused into the base reinforcing material and subsequent gelation, but before aging or drying the gel material. In yet another embodiment, the facing layer is attached to the base layer after aging and drying the gel material. In a preferred embodiment, the facing layer is attached to the reinforcing material of the base layer before infusing the sol-gel solution into the base reinforcing material. The facing layer can be solid and fluid-impermeable. The facing layer can be porous and fluid-permeable. In a preferred embodiment, the facing layer is porous and fluid-permeable and includes pores or holes having a diameter sufficient to allow fluid to diffuse through the facing material. In another preferred embodiment, the facing layer is attached to the reinforcement material of the base layer prior to infusing the sol-gel solution into the base reinforcement material, and the facing layer is porous, fluid-permeable, and includes pores or pores having a diameter large enough to allow fluid to diffuse through the facing material. In yet another preferred embodiment, the facing layer is attached to the open-cell foam reinforcement material prior to infusing the sol-gel solution into the foam reinforcement material, and the facing layer is porous, fluid-permeable, and includes pores or pores having a diameter large enough to allow fluid to diffuse through the facing material.

[0142] In some embodiments, the composite structure or the reinforced aerogel composite forming the composite structure may be encapsulated by an encapsulating member. For example, the encapsulating member may include one or more layers of material surrounding the composite or composite structure and / or a coating of material surrounding the composite or composite structure. For example, the encapsulating member may include a film, layer, envelope, or coating. The encapsulating member may be made of any material suitable for encapsulating the composite structure or the reinforced aerogel composite forming the composite structure. For example, the encapsulating member may reduce or eliminate the generation of dust or particulate material emanating from the composite structure.

[0143] The encapsulation member may include at least one vent that allows air to enter and exit the panel. The encapsulation member may include at least one filter that filters particulate matter. In an exemplary embodiment, the encapsulation member includes a vent that allows air to enter and exit the panel and a particulate filter on the vent that retains particulate matter within the encapsulation member. In another embodiment, the encapsulation member includes an edge seal that includes at least one vent and at least one particulate filter. In a further embodiment, the encapsulation member includes an edge seal that includes at least one vent and at least one particulate filter, where the vent in the edge seal allows air to enter and exit the edge of the encapsulation member, and the filter captures and retains particulate matter in the flowing air, preventing contamination of the air outside the encapsulation member with particulate matter. In some embodiments of the above aspects, the thermal control member or battery thermal management member may include multiple layers. For example, a thermal control element or battery thermal management element can include at least one layer of a thermally conductive material, or a layer including a thermally conductive material, e.g., the layer includes a metal, carbon, a thermally conductive polymer, or a combination thereof. As used in the context of these embodiments, a thermally conductive material refers to a material having a thermal conductivity greater than that of the aerogel composition. In certain embodiments, the thermally conductive material has a thermal conductivity greater than that of the aerogel composition by at least about one order of magnitude. In some embodiments, a thermal control element or battery thermal management element can include multiple layers of an aerogel composition. In certain embodiments, a thermal control element or battery thermal management element can include at least one layer of an electrically conductive material disposed adjacent to the aerogel composition. In certain embodiments, a thermal control element or battery thermal management element can include at least one layer of an electrically conductive material disposed between at least two of the multiple layers of an aerogel composition. In some embodiments, a thermal control element or battery thermal management element can include particles of an electrically conductive material disposed within a layer of the thermal control element or battery thermal management element, e.g., within a layer of the aerogel composition.

[0144] In exemplary embodiments, the thermal control element or battery thermal management element can include a material or layer of material that provides thermal capacitance (i.e., a heat-capacitive material), e.g., a material having a specific heat capacity of at least about 0.3 J / (gC). In some embodiments, the material with thermal capacitance has a specific heat capacity of at least about 0.5 J / (gC). For example, the material providing thermal capacitance can include a metal such as aluminum, titanium, nickel, steel, iron, or a combination thereof. In some embodiments, the thermal control element or battery thermal management element can include a layer or coating of a material with thermal capacitance. In some embodiments, the thermal control element or battery thermal management element can include particles of a material that provides thermal capacitance disposed within a layer of the thermal control element or battery thermal management element, e.g., within a layer of an aerogel composition. In certain embodiments, the thermal control element or battery thermal management element can include at least one layer of a material with thermal capacitance disposed adjacent to an aerogel composition. In certain embodiments, the thermal control element or battery thermal management element can include at least one layer of a material with thermal capacitance disposed between at least two of a plurality of layers of an aerogel composition. In exemplary embodiments, the thermal control element or battery thermal management element can include both a thermally conductive material and a thermally capacitive material. For example, the thermal control element or battery thermal management element can include a material that has both thermal capacitance and thermal conductivity, such as a metal, such as aluminum, titanium, nickel, steel, iron, or a combination thereof. In another example, the thermal control element or battery thermal management element can include one or more different materials or layers of materials, each having either thermal capacitance, thermal conductivity, or a combination thereof, such as a layer including a metal and a layer including a thermally conductive polymer.

[0145] In some embodiments, thermal paste can be used between layers of a thermal control or battery thermal management component to ensure uniform and consistent heat transfer between such layers. As used herein, thermal paste refers to various materials also known as thermal compounds, thermal greases, thermal interface materials (TIMs), thermal gels, heat pastes, heat sink compounds, and heat sink pastes. For example, a layer of thermal paste can be disposed between the aerogel composition and any other layer, such as one or more layers containing a thermally conductive or heat-capacitive material, one or more opposing layers, or an encapsulant.

[0146] As described herein, a thermal control element or battery thermal management element can include multiple layers of materials, such as insulating layers, thermally conductive layers, heat capacity layers, heat reflective layers, compressible layers, resilient or compliant layers, or combinations thereof. The combination of layers in a thermal control element or battery thermal management element can be selected to achieve a desired combination of properties, such as compressibility, resilience, thermal performance, pyrolysis, and other characteristics. In some embodiments, a thermal control element or battery thermal management element includes at least one resilient or compliant element disposed between one or more layers of a thermal protection material, such as a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, aerogel compositions, and combinations. The compliant or resilient element can include a compressible material, i.e., a material that can be compressed to reduce its thickness while providing a desired resistance to compression. For example, the compliant element can be a foam or other compressible material, such as polyolefin, polyurethane, phenolic, melamine, cellulose acetate, or polystyrene. In certain embodiments, the thermal control or battery thermal management member can also include at least one layer of a thermally conductive or heat-capacitive material disposed between the at least one compliant or resilient member and at least one of the multiple layers of reinforced aerogel composition. The thermally conductive or heat-capacitive material can absorb and / or dissipate heat within the thermal control or battery thermal management member. In some embodiments, the thermal control or battery thermal management member can further include a heat-reflective layer. For example, the heat-reflective layer can include a metal foil or sheet.

[0147] In embodiments of a thermal control or battery thermal management component that include several layers, the layers can be attached to other layers by an adhesive mechanism selected from the group consisting of, for example, aerosol adhesives, urethane-based adhesives, acrylate adhesives, hot melt adhesives, epoxies, rubber-resin adhesives, polyurethane composite adhesives, and combinations thereof. In some embodiments, the layers can be attached by a non-adhesive mechanism selected from the group consisting of, for example, flame gluing, needling, stitching, sealing bags, rivets, buttons, clamps, wraps, braces, and combinations thereof. In some embodiments, the layers can be attached using any combination of the adhesive and non-adhesive mechanisms described above.

[0148] FIG. 5 illustrates an exemplary thermal control element or battery thermal management element according to embodiments disclosed herein. As shown in FIG. 6, the exemplary thermal control element or battery thermal management element 10 includes a thermal protection layer 12, such as a reinforced aerogel composition. A layer of thermally conductive or heat capacitive material 14 is disposed adjacent to the thermal protection layer 12. The thermal control element or battery thermal management element 10 is substantially flat and has a first major outer surface defined by the outer surface of the first thermal protection layer 12 and a second major outer surface defined by the outer surface of the layer of thermally conductive or heat capacitive material 14. In some embodiments, the thermal control element or battery thermal management element 10 includes an encapsulation member or layer that surrounds all or a portion of the outer surface of the thermal control element or battery thermal management element. In some embodiments, the thermal protection layer may be surrounded by an encapsulation member or layer that surrounds all or a portion of the layer.

[0149] As shown in FIG. 7 , an exemplary thermal control or battery thermal management member 20 includes a first thermally protective layer 22, such as a layer of a reinforced aerogel composition, and a second thermally protective layer 23, such as a reinforced aerogel composition 23. A layer of thermally conductive or heat capacitive material 14 is disposed between the first thermally protective layer 22 and the second thermally protective layer 23. The thermal control or battery thermal management member 20 is substantially flat and has a first major outer surface defined by the outer surface of the first thermally protective layer 22 and a second major outer surface defined by the outer surface of the second thermally protective layer 23. In some embodiments, the thermal control or battery thermal management member 10 includes an encapsulation member or layer that surrounds all or a portion of the outer surface of the thermal control or battery thermal management member. In some embodiments, the thermally protective layer may be surrounded by an encapsulation member or layer that surrounds all or a portion of the layer.

[0150] As shown in FIG. 8 , an exemplary thermal control or battery thermal management member 30 includes a first thermally protective layer 32, e.g., a layer of a reinforced aerogel composition, and a second thermally protective layer 33, e.g., a layer of a reinforced aerogel composition. The thermal control or battery thermal management member 30 is substantially flat and has a first major outer surface defined by the outer surface of the first thermally protective layer 32 and a second major outer surface defined by the outer surface of the second thermally protective layer 33. A layer of compliant material 34 is disposed between the first and second thermally protective layers. A first layer 36 of thermally conductive or heat capacitive material is disposed between the first thermally protective layer 32 and the layer of compliant material 34. A second layer of thermally conductive or heat capacitive material 37 is disposed between the second thermally protective layer 33 and the layer of compliant material 34. In some embodiments, the thermal control or battery thermal management member 30 includes an encapsulation member or layer that surrounds all or a portion of the outer surface of the thermal control or battery thermal management member. In some embodiments, each thermal protection layer can be surrounded by an encapsulation member or layer that surrounds all or a portion of the layer.

[0151] As shown in FIG. 9 , an exemplary thermal control element or battery thermal management element 40 includes a first thermally protective layer 42, e.g., a layer of a reinforced aerogel composition, and a second thermally protective layer 43, e.g., a layer of a reinforced aerogel composition. The thermal control element or battery thermal management element 40 is substantially planar and has a first major outer surface defined by the outer surface of the first thermally protective layer 42 and a second major outer surface defined by the outer surface of the second thermally protective layer 43. A layer of compliant material 44 is disposed between the first and second thermally protective layers. A first layer 46 of a thermally conductive or heat capacitive material is disposed on the outer major surface of the first thermally protective layer 42. A second layer 47 of a thermally conductive or heat capacitive material is disposed on the outer major surface of the second thermally protective layer 43. In some embodiments, the thermal control element or battery thermal management element 40 includes an encapsulation member or layer that surrounds all or a portion of the outer surface of the thermal control element or battery thermal management element. In some embodiments, each thermally protective layer may be surrounded by an encapsulating member or layer that surrounds all or a portion of the layer.

[0152] As shown in FIG. 10 , an exemplary thermal control or battery thermal management member 50 includes a first thermal protection layer 52 and at least one elastic layer 54. In some embodiments, the thermal protection layer 52 is disposed adjacent to the elastic layer 54. In some embodiments, the thermal protection layer 52 is disposed in contact with the at least one elastic layer 54. For example, the thermal protection layer 52 can be bonded or adhered to the elastic layer 54, as disclosed in more detail herein. In some embodiments, the thermal control or battery thermal management member 50 includes an encapsulation member or layer that surrounds all or a portion of the outer surface of the battery thermal management member. In some embodiments, each thermal protection layer can be surrounded by an encapsulation member or layer that surrounds all or a portion of the thermal protection layer.

[0153] As shown in FIG. 11 , the thermal control member or exemplary battery thermal management member 60 includes a first thermal protection layer 62, at least one elastic layer 64, and a second thermal protection layer 66. In such embodiments, the first and second thermal protection layers can be disposed on opposite sides of the at least one elastic layer. In some embodiments, at least one of the thermal protection layers 62, 64 can be disposed adjacent to the elastic layer 64. In some embodiments, both of the thermal protection layers 62, 64 can be disposed adjacent to the elastic layer 64. In some embodiments, at least one of the thermal protection layers 62, 64 can be disposed in contact with the at least one elastic layer 64. In some embodiments, both of the thermal protection layers 62, 64 can be disposed in contact with the at least one elastic layer 64. For example, the thermal protection layer 62 can be bonded or adhered to the elastic layer 54, as disclosed in more detail herein. In some embodiments, the thermal control member or battery thermal management member 50 includes an encapsulation member or layer that surrounds all or a portion of the outer surface of the thermal control member or battery thermal management member. In some embodiments, each thermally protective layer may be surrounded by an encapsulating member or layer that surrounds all or a portion of the thermally protective layer.

[0154] In an exemplary embodiment, the compressible material comprises a material selected from the group consisting of siloxane, polyolefin, polyurethane, phenolic, melamine, cellulose acetate, and polystyrene. In an exemplary embodiment, the thermal protection layer comprises a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof. For example, at least one of the first and second thermal protection layers can comprise a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof. In another example, both the first and second thermal protection layers can comprise a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof.

[0155] In some embodiments, the thermally protective layer comprises an aerogel composition. For example, at least one of the first and second thermally protective layers can comprise an aerogel composition. In another example, both the first and second thermally protective layers can comprise an aerogel composition. The aerogel of the aerogel composition can comprise an inorganic, organic, or inorganic / organic hybrid material. In an exemplary embodiment, the aerogel composition is a silica aerogel composition. The aerogel composition can include a reinforcing material. For example, a reinforcing material is present in the aerogel composition. In some embodiments, the reinforcing material comprises fibers. For example, the fibers can be selected from the group consisting of discrete fibers, woven materials, nonwoven materials, needled nonwovens, battings, webs, mats, felts, and combinations thereof.

[0156] In any of the embodiments disclosed herein, the thermally protective layer can have a thermal conductivity sufficient to maintain at least the surface of the elastic or compressible layer below the decomposition temperature of the compressible material of the elastic or compressible layer. For example, the compressible material can include one or more organic materials that decompose at high temperatures. In such embodiments, the thermally protective layer(s) can maintain at least the surface of the elastic or compressible layer below the decomposition temperature of at least one of the organic materials. In some embodiments, the temperature of chemical decomposition of the elastic or compressible layer is greater than about 200°C. In some embodiments, the temperature of chemical decomposition of the elastic or compressible layer is greater than about 240°C. In some embodiments, the temperature of chemical decomposition of the elastic or compressible layer is greater than about 280°C. In some embodiments, the temperature of chemical decomposition of the elastic or compressible layer ranges from about 200°C to about 300°C. In some embodiments, the temperature of chemical decomposition of the elastic or compressible layer is greater than about 300°C. In some embodiments, the temperature of chemical decomposition of the elastic or compressible layer is greater than about 350°C. In some embodiments, the temperature of chemical decomposition of the elastic or compressible layer ranges from about 300°C to about 400°C.

[0157] The production of multilayer gel or aerogel compositions can include the following steps: a) attaching a fluid-permeable facing layer to a sheet of reinforcing material to produce a laminated reinforced sheet, the facing layer including pores or holes having a diameter large enough to allow fluid to diffuse through the facing material; b) injecting a gel precursor solution through the facing layer into the reinforced sheet; and c) transferring the gel precursor material into a gel material including a gel skeleton. A portion of the gel precursor solution is likely to be retained within the pores or holes of the facing layer such that the gel skeleton in the reinforcing material of the base layer extends into at least a portion of the facing layer. The resulting product is a multilayer gel composition including: a) at least one base layer including a reinforcing material and a gel skeleton integrated within the reinforcing material; and b) at least one facing layer including a fluid-permeable facing material and a gel skeleton integrated within the fluid-permeable facing material, wherein at least a portion of the gel skeleton of the base layer extends into and is continuous with at least a portion of the gel skeleton of the facing layer.

[0158] Large-scale production of multilayer aerogel compositions can include a conveyor-based system that includes the steps of: a) attaching at least one fluid-permeable facing layer to a sheet of reinforcing material to produce a laminated reinforced sheet, the facing layer containing pores or holes with a diameter large enough to allow fluid to diffuse therethrough; and b) combining a gel precursor solution with the laminated reinforced sheet at one end of the conveyor to produce a continuous, reinforced gel sheet laminate, wherein at least a portion of the gel precursor solution is injected through the facing layer and into the reinforced sheet, and the gel precursor solution is combined with the laminated reinforced sheet at a rate that allows the gel precursor solution to pass through the facing layer and penetrate into the reinforced sheet. In a preferred embodiment, the reinforcing material comprises an open-cell foam reinforcing material.

[0159] The reinforced laminated gel sheet can be wound in multiple layers (preferably around a mandrel with uniform tension) and processed through subsequent chemical treatment, aging, and drying steps. To facilitate aging or drying of the gel material, additional separator layers can be co-wound between the gel sheet layers, for example, to provide flow channels for aging agents or drying materials. In a preferred embodiment, the opposing layer provides flow channels for the aging agent or drying material so that additional separator layers are not required for aging and drying of the gel material.

[0160] Large-scale production of multilayer aerogel compositions can include a semi-continuous batch-based process, commonly referred to as the gel-in-roll process, which involves the following steps: a) applying a fluid-permeable facing layer to a sheet of reinforcement material, the facing layer containing pores or holes with a diameter large enough to allow fluid to diffuse therethrough; b) rolling the laminated reinforcement material into multiple layers as a preform roll; and c) combining a gel precursor solution with the preform roll. An additional separator layer may be co-rolled with the reinforcement material within the preform roll to provide flow channels for the gel precursor solution, aging agent, and drying material. In a preferred embodiment, the facing layer provides flow channels for the gel precursor solution, aging agent, and drying material such that an additional separator layer is not required. In a preferred embodiment, the reinforcement material comprises an open-cell foam reinforcement material.

[0161] Aerogel compositions according to embodiments of the present disclosure can be formed into a variety of end products. In the simplest configuration, the reinforced aerogel composition can be in the form of a sheet. The sheet can be formed continuously or semi-continuously, e.g., as a rolled product, or the sheet can be cut to the desired size and shape or formed from a larger sheet. The sheet material can be used to form a thermal barrier between battery cells. In other configurations, the reinforced aerogel composition can be formed into pouches to house, for example, pouch cells of a battery, or into cylinders to house cylindrical battery cells.

[0162] The aerogel composites of the present disclosure can be molded into a variety of three-dimensional shapes, including panels, pipe preforms, half-shell preforms, elbows, fittings, pouches, cylinders, and other shapes typically required for applying thermal insulation materials to industrial and commercial applications. In one embodiment, the reinforcing material is formed into the desired shape before the gel precursor material is infused. The gel material is processed to allow the preform to maintain its shape, thus resulting in a reinforced aerogel preform of the desired shape. This technique for forming shaped aerogel preforms can be difficult and inefficient due to the difficulties required to process gel materials in various shapes and configurations.

[0163] In exemplary embodiments of the present disclosure, aerogels can be formed from a gel precursor or combination of gel precursors that contain at least one hydrophobic group. Such aerogels, e.g., inorganic aerogels such as silica-based aerogels, can contain hydrophobically bonded silicon. For example, the source of the hydrophobically bonded silicon in the aerogel can be one or more hydrophobic precursor materials. In embodiments of the present disclosure, aerogels formed from such precursors can be hydrophobic. In some embodiments, aerogels formed from such precursors can be inherently hydrophobic.

[0164] In the context of this disclosure, the term "intrinsically hydrophobic" refers to a material that possesses hydrophobic properties without modification by a hydrophobizing agent. For example, aerogels can be treated to impart or improve hydrophobicity. The hydrophobizing treatment can be applied to the sol-gel solution, the wet gel before liquid-phase extraction, or the aerogel after liquid-phase extraction. The hydrophobizing treatment can be carried out by reacting hydroxy moieties on the gel, such as silanol groups (Si-OH) present in the framework of the silica gel, with functional groups of the hydrophobizing agent. The resulting reaction converts the silanol groups and hydrophobizing agent into hydrophobic groups in the framework of the silica gel. The hydrophobizing agent compound can be reacted with the following reaction: R N MX 4-N (Hydrophobizing agent) + MOH (silanol) → MOMR NThe (hydrophobic group) + HX can react with the hydroxyl groups of the gel. The hydrophobic treatment can be performed on both the outer macroscopic surface of the silica gel and the inner pore surface within the porous network of the gel. Published U.S. Patent Application Publication No. 2016 / 0096949 (paragraphs

[0044] to

[0048] ) teaches hydrophobic treatment and is incorporated herein by reference according to the individually cited paragraphs. However, as noted above, aerogels according to embodiments of the present disclosure are hydrophobic without hydrophobic treatment, for example, without treatment with a hydrophobizing agent.

[0165] The production of aerogels generally involves the following steps: i) forming a sol-gel solution, ii) forming a gel from the sol-gel solution, and iii) extracting the solvent from the gel material by innovative processing and extraction to obtain a dried aerogel material. This method is described in more detail below, particularly in relation to the formation of inorganic aerogels, such as silica aerogels. However, the specific examples and illustrations provided herein are not intended to limit the present disclosure to any particular type of aerogel and / or preparation method. The present disclosure, unless otherwise specified, can include any aerogel formed by any relevant preparation method known to those of skill in the art.

[0166] The first step in forming inorganic aerogels is typically the formation of a sol-gel solution by hydrolysis and condensation of a silica precursor, such as, but not limited to, a metal alkoxide precursor, in an alcohol-based solvent. Key variables in the formation of inorganic aerogels include the type of alkoxide precursor included in the sol-gel solution, the nature of the solvent, the processing temperature and pH of the sol-gel solution (which can be altered by the addition of acid or base), and the precursor / solvent / water ratio within the sol-gel solution. Controlling these variables during the formation of the sol-gel solution can allow for control of the growth and aggregation of the gel skeleton during the subsequent transition of the gel material from the "sol" state to the "gel" state. The properties of the resulting aerogel are affected by the pH and molar ratio of the reactants in the precursor solution; however, any pH and any molar ratio that allows for gel formation can be used in this disclosure.

[0167] The sol-gel solution is formed by combining at least one gelation precursor with a solvent. Suitable solvents for use in forming the sol-gel solution include lower alcohols with 1 to 6 carbon atoms, particularly 2 to 4 carbon atoms, although other solvents known to those skilled in the art can be used. Examples of useful solvents include, but are not limited to, methanol, ethanol, isopropanol, ethyl acetate, ethyl acetoacetate, acetone, dichloromethane, and tetrahydrofuran. Multiple solvents can also be combined to achieve a desired level of dispersion or to optimize the properties of the gel material. Therefore, the selection of the optimal solvent for the sol-gel and gel formation steps depends on the specific precursors, fillers, and additives incorporated into the sol-gel solution, the target processing conditions for gelation and liquid extraction, and the desired properties of the final aerogel material.

[0168] Water may also be present in the precursor-solvent solution. The water acts to hydrolyze the metal alkoxide precursor to a metal hydroxide precursor. The hydrolysis reaction can be (using TEOS in an ethanol solvent as an example): Si(OC2H5)4 + 4H2O → Si(OH)4 + 4(C2H5OH). The resulting hydrolyzed metal hydroxide precursor remains 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 precursor can occur as follows: 2Si(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.

[0169] Acids and bases can be incorporated into the sol-gel solution to control the pH of the solution and catalyze the hydrolysis and condensation reactions of the precursor materials. Any acid can be used to catalyze the precursor reaction and achieve a lower pH solution; exemplary acids include HCl, H2SO4, H3PO4, oxalic acid, and acetic acid. Any base can also be used to catalyze the precursor reaction and achieve a higher pH solution; exemplary bases include NH4OH.

[0170] A strong base can be used to catalyze the precursor reaction, resulting in a solution with a higher pH. Using a strong base to catalyze the precursor reaction allows for significantly higher hydrophobic inorganic precursor material content, such as MTES or DMDES, than would be possible using a weak base, such as a base containing NH4OH. In the context of the present disclosure, the term "strong base" refers to both inorganic and organic bases. For example, a strong base according to embodiments herein includes a cation selected from the group consisting of lithium, calcium, sodium, potassium, rubidium, barium, strontium, and guanidinium. In another example, the basic catalyst used to catalyze the precursor reaction can include a catalytic amount of sodium hydroxide, lithium hydroxide, calcium hydroxide, potassium hydroxide, strontium hydroxide, barium hydroxide, guanidine hydroxide, sodium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium hydroxide, choline hydroxide, phosphonium hydroxide, DABCO, DBU, a guanidine derivative, an amidine, or a phosphazene.

[0171] The sol-gel solution can include additional co-gelling precursors, as well as filler materials and other additives. The filler materials and other additives may be dispensed into the sol-gel solution at any time before or during the formation of the gel. The filler materials and other additives may also be incorporated into the gel material after gelation by various techniques known to those skilled in the art. In certain embodiments, the sol-gel solution, including the gelling precursors, solvent, catalyst, water, filler materials, and other additives, is a homogeneous solution capable of forming an effective gel under appropriate conditions.

[0172] Once the sol-gel solution is formed and optimized, the gel-forming components in the sol-gel can be converted into a gel material. The process of converting the gel-forming components into a gel material involves an initial gel formation step in which the gel solidifies to the gel point of the gel material. The gel point of the gel material can be considered the point at which the gelling solution exhibits resistance to flow and / or forms a substantially continuous polymer backbone throughout its volume. Various gel formation techniques are known to those skilled in the art. Examples include, but are not limited to, maintaining the mixture in a quiescent state for a sufficient period of time, adjusting the pH of the solution, adjusting the temperature of the solution, directing a form of energy (ultraviolet, visible, infrared, microwave, ultrasound, particle radiation, electromagnetic) to the mixture, or a combination thereof.

[0173] The process of converting gel-forming components (gel precursors) into a gel material can also include an aging step (also called curing) prior to liquid extraction or removal of the solvent from the gel (also called drying the gel). Aging the gel material after reaching the gel point can further strengthen the gel framework by increasing the number of crosslinks within the network. The duration of gel aging can be adjusted to control various properties within the resulting aerogel material. This aging process can be useful to prevent potential volume loss and shrinkage during liquid extraction. Aging can involve maintaining the gel in a quiescent state for an extended period of time (prior to extraction), maintaining the gel at an elevated temperature, adding a crosslinking-promoting compound, or any combination thereof. Preferred temperatures for aging are typically from about 10°C to about 100°C, although other suitable temperatures are also contemplated herein. Aging of the gel material typically continues until liquid extraction of the wet gel material.

[0174] The time for transitioning the gel-forming material (gel precursor) into a gel material includes both the duration of initial gel formation (from the onset of gelation to the point of gelation) and the duration of subsequent hardening and aging of the gel material (from the point of gel to the onset of liquid extraction / solvent removal) prior to extraction of liquid or removal of solvent from the gel (also referred to as drying of the gel). The total time for transitioning the gel-forming material into a gel material is typically between about 1 minute and several days, typically 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, preferably about 1 hour or less, about 30 minutes or less, about 15 minutes or less, or about 10 minutes or less.

[0175] In another embodiment, the resulting gel material can be washed with a suitable secondary solvent to replace the primary reaction solvent present in the wet gel. Such secondary solvents can be linear monohydric alcohols having one or more aliphatic carbon atoms, dihydric alcohols having two or more carbon atoms, branched alcohols, cyclic alcohols, alicyclic alcohols, aromatic alcohols, polyhydric alcohols, ethers, ketones, cyclic ethers, or derivatives thereof. In another embodiment, the resulting gel material can be washed with an additional amount of the same solvent present in the gel material to, among other things, remove any undesired by-products or other precipitates in the gel material.

[0176] Once the gel material has been formed and processed, the gel liquid can then be at least partially extracted from the wet gel using extraction methods, including innovative processing and extraction techniques, to form an aerogel material. Liquid extraction plays a key role in manipulating aerogel properties, such as porosity and density, as well as related properties such as thermal conductivity, among other factors. Generally, aerogels are obtained when the liquid is extracted from the gel in a manner that causes low shrinkage in the porous network and framework of the wet gel. This liquid extraction may also be referred to as solvent removal or drying, among other things.

[0177] An alternative method for forming silica aerogel uses metal oxide salts such as sodium silicate, also known as water glass. First, a water glass solution is produced by mixing sodium silicate with water and acid to form a silicic acid precursor solution. Salt by-products can be removed from the silicic acid precursor by ion exchange, surfactant separation, membrane filtration, or other chemical or physical separation techniques. The resulting sol can then be gelled, such as by adding a base catalyst, to produce a hydrogel. The hydrogel can be washed to remove any residual salts or reactants. Water can then be removed from the gel pores by exchange with a polar organic solvent, such as ethanol, methanol, or acetone. The liquid in the gel is then at least partially extracted using innovative processing and extraction techniques.

[0178] Aerogels are generally formed by removing a liquid mobile phase from a gel material at temperatures and pressures near or above the critical point of the liquid mobile phase. Upon reaching or exceeding the critical point (near-critical, i.e., the system's pressure and temperature are equal to or greater than the critical pressure and critical temperature, respectively), a new supercritical phase, distinct from the liquid or gas phase, emerges in the fluid. The solvent can then be removed without introducing a liquid-vapor interface, capillary pressure, or any of the related mass transfer limitations typically associated with liquid-vapor boundaries. Furthermore, the supercritical phase is generally more miscible with organic solvents and therefore has better extraction capabilities. Cosolvents and solvent exchange are also commonly used to optimize supercritical fluid drying processes.

[0179] If evaporation or extraction occurs well below the critical point, capillary forces resulting from 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 adverse effects of such capillary forces. In certain embodiments of the present disclosure, the use of near-critical conditions, just below the critical point of the solvent system, allows for the production of aerogel materials or compositions with sufficiently low shrinkage to produce commercially viable final products.

[0180] Several additional aerogel extraction techniques are known in the art, including various approaches to the use of supercritical fluids in drying aerogels. For example, Kistler (J. Phys. Chem. (1932) 36:52-64) describes a simple supercritical extraction process in which the gel solvent is maintained above its critical pressure and temperature, thereby reducing evaporation capillary forces and maintaining the structural integrity of the gel network. U.S. Patent No. 4,610,863 describes an extraction process in which the gel solvent is exchanged with liquid carbon dioxide, followed by extraction under conditions in which the carbon dioxide is in a supercritical state. U.S. Patent No. 6,670,402 teaches extracting liquid from gels via rapid solvent exchange by injecting supercritical (rather than liquid) carbon dioxide into an extractor preheated and prepressurized substantially above the supercritical state, thereby producing an aerogel. U.S. Patent No. 5,962,539 describes a method for obtaining aerogels from polymeric materials in sol-gel form in organic solvents by exchanging the organic solvent with a fluid having a critical temperature below the polymer decomposition temperature and extracting the fluid / sol-gel using a supercritical fluid such as supercritical carbon dioxide, supercritical ethanol, or supercritical hexane. U.S. Patent No. 6,315,971 discloses a method for producing a gel composition, which involves drying a wet gel containing a gel solid and a desiccant to remove the desiccant under conditions sufficiently dry to reduce gel shrinkage during drying. U.S. Patent No. 5,420,168 describes a method by which resorcinol / formaldehyde aerogels can be produced using a simple air-drying procedure. U.S. Patent No. 5,565,142 describes a drying technique that modifies the gel surface to make it stronger and more hydrophobic so that the gel skeleton and pores can resist collapse during ambient drying or subcritical extraction. Other examples of extracting liquids from aerogel materials can be found in U.S. Patents Nos. 5,275,796 and 5,395,805. US Patent Application Publication No. 2019 / 0161909 provides an example of a method using alkoxysilanes and water glass to produce dense aerogels.

[0181] One embodiment for extracting liquid from a wet gel involves, for example, first using a supercritical fluid such as carbon dioxide, which essentially replaces the primary solvent present in the gel's pore network with liquid carbon dioxide. The wet gel (typically in an autoclave) is then heated above the critical temperature of carbon dioxide (approximately 31.06°C) to increase the system pressure to a pressure higher than the critical pressure of carbon dioxide (approximately 1070 psig). The pressure surrounding the gel material can be slightly varied to facilitate the removal of the liquid from the gel. Carbon dioxide can be recirculated through the extraction system to facilitate the continuous 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. The carbon dioxide can also be pretreated to a supercritical state before being injected into the extraction chamber.

[0182] Another example of an alternative method for forming aerogels involves chemical modification of the matrix material in the wet gel state via conversion of surface hydroxyl groups to hydrophobic trimethylsilyl ethers to reduce damaging capillary pressures at the solvent / pore interface, thereby allowing liquid extraction from the gel material at temperatures and pressures below the critical point of the solvent.

[0183] In yet another embodiment, the liquid (solvent) in the gel material may be frozen at a lower temperature, followed by a sublimation process to remove the solvent from the gel material. Such removal or drying of the solvent from the gel material is understood to be within the scope of the present disclosure. Such removal largely preserves the gel structure, thus producing an aerogel with unique properties.

[0184] Large-scale production of aerogel materials or compositions can be complicated by the difficulties associated with continuously forming gel materials at large scales. Additionally, there are difficulties associated with extracting liquid from large volumes of gel materials using innovative processing and extraction techniques. In certain embodiments, the disclosed aerogel materials or compositions are amenable to large-scale production. In certain embodiments, the disclosed gel materials can be produced at large scales by continuous casting and gelation processes. In certain embodiments, the disclosed aerogel materials or compositions are produced at large scales, requiring the use of large-scale extraction vessels. The disclosed large-scale extraction vessels are typically about 0.1 m 3 More than 0.25m 3 More than 0.5m 3 or more, or approximately 0.75 m 3 The extraction vessel may include an extraction vessel having a volume equal to or greater than 1000 vol.

[0185] The aerogel compositions of the present disclosure can have a thickness of 15 mm or less, 10 mm or less, 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, 0.5 mm or less, 0.3 mm or less, or a range of thicknesses between any combination of the aforementioned thicknesses.

[0186] The aerogel composition may be reinforced with various reinforcing materials to achieve a more flexible, resilient, and conformable composite product. Reinforcing materials can be added to the gel at any point during the gelation process to produce a wet, reinforced gel composition. The wet gel composition can then be dried to produce a reinforced aerogel composition.

[0187] Aerogel compositions may be OCMF-reinforced with various open-cell macroporous skeletal reinforcing materials to achieve a more flexible, resilient, and conformable composite product. OCMF-reinforcing materials can be added to the gel at any point during the gelation process prior to gelation to produce a wet-reinforced gel composition. The wet gel composition can then be dried to produce an OCMF-reinforced aerogel composition. OCMF-reinforcing materials can be formed from organic polymeric materials, such as melamine or melamine derivatives, and exist in the form of continuous sheets or panels.

[0188] Melamine OCMF materials can be produced from a melamine-formaldehyde precondensate solution. An aqueous solution of the melamine-formaldehyde condensate is produced by combining the melamine-formaldehyde precondensate with a solvent, an emulsifier / dispersant, a curing agent such as an acid, and a blowing agent such as a C5 to C7 hydrocarbon. The melamine-formaldehyde solution or resin is then cured at an elevated temperature above the boiling point of the blowing agent to produce an OCMF containing numerous interconnected, three-dimensionally branched melamine structures with a corresponding network of interconnected pores embedded within the framework. The melamine-formaldehyde precondensate generally has a formaldehyde-to-melamine molar ratio ranging from 5:1 to 1.3:1, typically ranging from 3.5:1 to 1.5:1. The precondensate can be in the form of a powder, spray, resin, or solution. The solvent included in the melamine-formaldehyde precondensate solution can include alcohols such as methanol, ethanol, or butanol.

[0189] The emulsifier / dispersant contained in the melamine-formaldehyde precondensate solution can include anionic surfactants, cationic emulsifiers, or nonionic surfactants. Useful anionic surfactants include, but are not limited to, diphenylene oxide sulfonates, alkane- and alkylbenzene sulfonates, alkylnaphthalene sulfonates, olefin sulfonates, alkyl ether sulfonates, fatty alcohol sulfates, ether sulfates, α-sulfofatty acid esters, acylaminoalkane sulfonates, acyl isethionates, alkyl ether carboxylates, N-acylsarcosinates, alkyl, and alkyl ether phosphates. Useful cationic emulsifiers include, but are not limited to, alkyltriammonium salts, alkylbenzyldimethylammonium salts, or alkylpyridinium salts. Useful nonionic surfactants include, but are not limited to, alkylphenol polyglycol ethers, fatty alcohol polyglycol ethers, fatty acid polyglycol ethers, fatty acid alkanolamides, ethylene oxide-propylene oxide block copolymers, amine oxides, glycerol fatty acid esters, sorbitan esters, and alkyl polyglycosides. The emulsifier / dispersant can be added in an amount of 0.2% to 5% by weight based on the melamine-formaldehyde precondensate.

[0190] The curing agent contained in the melamine-formaldehyde precondensate solution can include an acidic compound. The amount of these curing agents generally ranges from 0.01% to 20% by weight, typically from 0.05% to 5% by weight, all based on the melamine-formaldehyde precondensate. Useful acidic compounds include, but are not limited to, organic and inorganic acids, such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, oxalic acid, toluenesulfonic acid, amidosulfonic acid, acid anhydrides, and mixtures thereof.

[0191] The blowing agent contained in the melamine-formaldehyde precondensate solution can include physical or chemical blowing agents. Useful physical blowing agents include, but are not limited to, hydrocarbons such as pentane and hexane, halogenated hydrocarbons, more specifically chlorinated and / or fluorinated hydrocarbons such as methylene chloride, chloroform, trichloroethane, chlorofluorocarbons, and hydrochlorofluorocarbons (HCFCs), alcohols such as methanol, ethanol, n-propanol, or isopropanol, ethers, ketones, and esters such as methyl formate, ethyl formate, methyl acetate, or ethyl acetate, and gases such as air, nitrogen, or carbon dioxide. In certain embodiments, it is preferable to add a physical blowing agent having a boiling point between 0°C and 80°C. Useful chemical blowing agents include, but are not limited to, isocyanates mixed with water (which release carbon dioxide as an active blowing agent), carbonates and / or bicarbonates mixed with acids (which release carbon dioxide as an active blowing agent), and azo compounds such as azodicarbonamide. The blowing agent is present in the melamine-formaldehyde precondensate solution in an amount of 0.5% to 60% by weight, particularly 1% to 40% by weight, and in particular embodiments 1.5% to 30% by weight, based on the melamine-formaldehyde precondensate.

[0192] The melamine-formaldehyde precondensate solution can be formed into a melamine OCMF material by heating the solution to a temperature generally above the boiling point of the blowing agent used, thereby forming an OCMF containing numerous interconnected, three-dimensionally branched melamine structures with a corresponding network of interconnected open-cell pores embedded within the framework. The introduction of thermal energy may be via electromagnetic radiation, e.g., high-frequency radiation of 5 to 400 kW, e.g., 5 to 200 kW, and in certain embodiments, 9 to 120 kW per kilogram of mixture used in the frequency range of 0.2 to 100 GHz, more specifically 0.5 to 10 GHz. Magnetrons are useful sources of dielectric radiation; one magnetron or two or more magnetrons can be used simultaneously.

[0193] The OCMF material can be dried to remove residual liquids (water, solvents, blowing agents) from the OCMF material. A post-treatment can also be used to hydrophobize the OCMF material. This post-treatment can use a hydrophobic coating agent with high thermal stability and / or low flammability, such as silicone, silicone salts, or fluorinated compounds.

[0194] The density of the melamine OCMF is generally in the range of 0.005 to 0.3 g / cc, for example, in the range of 0.01 to 0.2 g / cc, and in certain embodiments, in the range of 0.03 to 0.15 g / cc, or most specifically, in the range of 0.05 to 0.15 g / cc. The average pore size of the melamine OCMF is generally in the range of 10 μm to about 1000 μm, and more particularly, in the range of 50 to 700 μm.

[0195] In embodiments, the OCMF reinforcing material is incorporated into the aerogel composition as a continuous sheet. This process involves first producing a continuous sheet of OCMF-reinforced gel by casting or impregnating a gel precursor solution onto a continuous sheet of OCMF reinforcing material and forming the material into a reinforced gel composite sheet. The liquid can then be at least partially extracted from the OCMF-reinforced gel composite sheet to produce a sheet of OCMF-reinforced aerogel composition.

[0196] The aerogel composition may contain an opacifying agent to reduce the radiative component of heat transfer. An opacifying compound or its precursor can be dispersed in the mixture containing the gel precursor at any time prior to gel formation. Examples of opacifying compounds include, but are not limited to, boron carbide (BC), diatomaceous earth, manganese ferrite, MnO, NiO, SnO, AgO, BiO, carbon black, graphite, titanium oxide, titanium iron oxide, aluminum oxide, zirconium silicate, zirconium oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, titanium iron oxide (ilmenite), chromium oxide, carbides (e.g., SiC, TiC, or WC), or mixtures thereof. Examples of opacifying compound precursors include, but are not limited to, TiOSO4 or TiOCl2. In some embodiments, the opacifying compound used as an additive may exclude silicon carbide whiskers or fibers. When an aerogel composition is intended for use in an electrical device, such as a battery as a barrier layer or other related application, the composition including the opacifier can desirably have high dielectric strength with high volume and surface resistivity. In such embodiments, the carbon additive used as the opacifier can be non-conductive or modified to reduce its conductivity. For example, the opacifier can be surface oxidized to reduce its conductivity. In some embodiments, a carbonaceous additive with inherent conductivity can be used as an opacifier in an aerogel composition intended for use in an electrical device. In such embodiments, the conductive carbonaceous additive can be used at a concentration below the percolation threshold to provide a composition with a dielectric strength suitable for use in an electrical device.

[0197] The aerogel composition can include one or more fire-class additives. In the context of this disclosure, the term "fire-class additive" refers to a material that has an endothermic effect in the context of a response to a fire and that can be incorporated into the aerogel composition. Additionally, in certain embodiments, the fire-class additive can inhibit the thermal decomposition (T) of the aerogel composition in which the fire-class additive is present. d) is higher than the onset of endothermic decomposition (E D ), and in certain embodiments, the T of the aerogel composition in which the fire-class additive is present. d E is lower than 50°C D In other words, the E of fire-class additives D is in the following range

number

number

number

[0198] Prior to, simultaneously with, or even subsequent to incorporation or mixing with the sol (e.g., silica sol prepared from alkyl silicates or water glass by various methods as understood in the prior art), the fire-class additive can be mixed or otherwise dispersed in a medium containing ethanol and, optionally, up to 10% by volume of water. The mixture can be mixed and / or stirred as needed to achieve a substantially uniform dispersion of the additive in the medium. Without being bound by theory, utilizing the hydrated forms of the clays and other fire-class additives provides an additional endothermic effect. For example, halloysite clay (commercially available from Applied Minerals, Inc. under the trade name DRAGONITE or simply Halloysite from Imerys) and kaolinite clay are hydrated forms of aluminum silicate clays that have an endothermic effect by releasing water of hydration at high temperatures (gas dilution). As another example, hydrated forms of carbonates can release carbon dioxide when heated or at high temperatures.

[0199] In the context of this disclosure, the term "heat of dehydration" means the amount of heat required to vaporize water (and dihydroxylation, if applicable) from a material that is in its hydrated form when not exposed to elevated temperatures. Heat of dehydration is typically expressed on a unit weight basis.

[0200] In certain embodiments, the fire-class additives of the present disclosure have an onset of thermal decomposition of about 100°C or greater, about 130°C or greater, about 200°C or greater, about 230°C or greater, about 240°C or greater, about 330°C or greater, 350°C or greater, about 400°C or greater, about 415°C or greater, about 425°C or greater, about 450°C or greater, about 500°C or greater, about 550°C or greater, about 600°C or greater, about 650°C or greater, about 700°C or greater, about 750°C or greater, about 800°C or greater, or a range between any two of these values. In certain embodiments, the fire-class additives of the present disclosure have an onset of thermal decomposition of about 440°C or 570°C ... d Thermal decomposition begins at approximately 50°C or less, approximately 40°C or less, approximately 30°C or less, approximately 20°C or less, approximately 10°C or less, approximately 5°C or less, or within a range between any two of these values.

[0201] Fire-class additives of the present disclosure include phyllosilicate clays (such as illite), kaolin or kaolinite (aluminum silicate; Al2Si2O5(OH)4), metakaolin, halloysite (aluminum silicate; Al2Si2O5(OH)4), endellite (aluminum silicate; Al2Si2O5(OH)4), mica (silica mineral), diaspore (aluminum oxide hydroxide; α-AlO(OH)), gibbsite (aluminum hydroxide), boehmite (aluminum oxide hydroxide; γ-AlO(OH)), montmorillonite, beidellite, pyrophyllite (aluminum silicate; Al2Si4O 10These include, but are not limited to, clay materials such as smectite, levrierite, letolite, celadonite, attapulgite, chloropar, volkonskoite, allophane, racevinite, zillnite, sebelite, myrosilite, corerite, simolite, and newtonite, sodium bicarbonate (NaHCO), magnesium hydroxide (or magnesium dihydroxide, "MDH"), alumina trihydrate ("ATH"), gypsum (calcium sulfate dihydrate; CaSO 2H O), barringtonite (MgCO 2H O), nesquehonite (MgCO 3H O), lansfordite (MgCO 5H O), hydromagnesite (hydrated magnesium carbonate; Mg(CO)(OH) 4H O), dolomite, and other carbonates such as, but not limited to, lithium carbonate. Among clay materials, certain embodiments of the present disclosure use clay materials with at least a partial layered structure. In certain embodiments of the present disclosure, the clay material as a fire-class additive in the aerogel composition has at least some water, such as a hydrated form. The additive may be in a hydrated crystalline form or may be hydrated during the manufacturing / processing of the disclosed compositions. In certain embodiments, the fire-class additive also includes a low-melting-point additive that absorbs heat without changing its chemical composition. An example of this class is a low-melting-point glass, such as inert glass beads. Other additives that may be useful in the compositions of the present disclosure include, but are not limited to, wollastonite (calcium silicate) and titanium dioxide (TiO2). In certain embodiments, other additives may include infrared opacifiers, such as, but not limited to, titanium dioxide or silicon carbide; ceramicizers, such as, but not limited to, low-melting-point glass frits; calcium silicate; or carbides, such as, but not limited to, phosphates and sulfates. In certain embodiments, additives may require special processing considerations, such as techniques to ensure that the additives are uniformly distributed and do not aggregate significantly to cause variability in product performance. Processing techniques may include additional static and dynamic mixers, stabilizers, adjustment of process conditions, and others known in the art.

[0202] The amount of additive in the aerogel compositions disclosed herein can depend on the desired properties of the composition. The amount of additive used during the preparation and processing of sol-gel compositions is typically referred to as a weight percent relative to the silica content of the sol. The amount of additive in the sol can vary from about 5% to about 70% by weight relative to the silica content. In certain embodiments, the amount of additive in the sol is 10% to 60% by weight relative to the silica content, and in certain preferred embodiments, it is 20% to 40% by weight relative to the silica content. In exemplary embodiments, the amount of additive in the sol relative to the silica content ranges from about 5% to about 20%, about 10% to about 20%, about 10% to about 30%, about 10% to about 20%, about 30% to about 50%, about 35% to about 45%, or about 35% to about 40% by weight relative to the silica content. In some embodiments, the amount of additive in the sol is at least about 10% by weight relative to the silica content or about 10% by weight relative to the silica content. In some embodiments, the amount of additive ranges from about 5% to about 15% by weight relative to the silica content. In certain embodiments, there may be more than one type of additive. One or more fire-class additives may also be present in the final aerogel composition. In some preferred embodiments including an aluminum silicate fire-class additive, the additive is present in the aerogel composition at about 60 to 70% by weight relative to the silica content. For example, in some preferred embodiments including an aluminum silicate fire-class additive, e.g., kaolin, or a combination of aluminum silicate fire-class additives, e.g., kaolin and alumina trihydrate ("ATH"), the total amount of additive present in the aerogel composition is about 30 to 40% by weight relative to the silica content. As another example, in some preferred embodiments including silicon carbide additive, the total amount of additive present in the aerogel composition is about 30 to 40% by weight, e.g., 35% by weight, relative to the silica content. As another example, in some preferred embodiments including silicon carbide additive, the total amount of additive present in the aerogel composition is about 5 to 15% by weight, e.g., 10% by weight, relative to the silica content.

[0203] When referring to the final reinforced aerogel composition, the amount of additive is typically referred to as a weight percent of the final reinforced aerogel composition. The amount of additive in the final reinforced aerogel composition can vary from about 1% to about 50%, about 1% to about 25%, or about 10% to about 25% of the weight of the reinforced aerogel composition. In exemplary embodiments, the amount of additive in the final reinforced aerogel composition ranges from about 10% to about 20% by weight of the reinforced aerogel composition. In exemplary embodiments, the amount of additive in the final reinforced aerogel composition as a weight percentage of the composition is about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, or a range between any of the aforementioned percentages. In certain embodiments, the amount of additive in the final reinforced aerogel composition is about 15% by weight of the reinforced aerogel composition. In certain embodiments, the amount of additive in the final reinforced aerogel composition is about 13% by weight of the reinforced aerogel composition. For example, in some preferred embodiments including an additive such as silicon carbide, the total amount of additive present in the aerogel composition is about 10 to 20% by weight of the reinforced aerogel composition, e.g., about 15%. As another example, in some preferred embodiments where the additive includes silicon carbide, the total amount of additive present in the aerogel composition is about 3 to 5% by weight of the reinforced aerogel composition, e.g., about 4%.

[0204] In certain embodiments, fire-class additives can be classified or grouped based on their onset thermal decomposition temperature. For example, fire-class additives can be classified or grouped as having a thermal decomposition onset temperature of less than about 200°C, less than about 400°C, or greater than about 400°C. For example, additives with a thermal decomposition onset temperature of less than about 200°C include sodium bicarbonate (NaHCO), nesquehonite (MgCO·3H2O), and gypsum (calcium sulfate dihydrate, CaSO·2H2O). In another example, additives with a thermal decomposition onset temperature of less than about 400°C include alumina trihydrate ("ATH"), hydromagnesite (hydrated magnesium carbonate, Mg5(CO3)4(OH)2·4H2O), and magnesium hydroxide (or magnesium dihydroxide, "MDH"). In another example, additives with a thermal decomposition onset temperature below about 400°C include halloysite (aluminum silicate; Al2Si2O5(OH)4), kaolin or kaolinite (aluminum silicate Al2Si2O5(OH)4), boehmite (aluminum oxide hydroxide; γ-AlO(OH)), or a high temperature phase change material (PCM).

[0205] In certain embodiments of the present disclosure, clay materials, e.g., aluminosilicate clays such as halloysite or kaolinite, as additives to aerogel compositions are in dehydrated forms, e.g., metahalloysite or metakaolin. Other additives that may be useful in the compositions of the present disclosure include, but are not limited to, wollastonite (calcium silicate) and titanium dioxide (TiO2). In certain embodiments, other additives may include, but are not limited to, infrared opacifiers such as titanium dioxide or silicon carbide, ceramifiers such as, but not limited to, low-melting-point glass frits, calcium silicate, or carbides such as, but not limited to, phosphates and sulfates. In certain embodiments, additives may require special processing considerations, such as techniques to ensure that the additives are uniformly distributed and do not aggregate significantly, causing variability in product performance. Processing techniques may include additional static and dynamic mixers, stabilizers, adjustments to process conditions, and others known in the art. One or more fire-class additives may also be present in the final aerogel composition.

[0206] In certain embodiments, the inclusion of additives, such as aluminosilicate clay-based materials like halloysite or kaolin, in the aerogel materials and compositions of the present disclosure can impart improved high-temperature shrinkage properties. Test methods for high-temperature shrinkage include, for example, the "Standard Test Method for Linear Shrinkage of Preformed High-Temperature Thermal Insulation Subjected to Soaking Heat" (ASTM C356, ASTM International, West Conshohocken, Pennsylvania). Such tests, called "thermal soaks," expose materials to temperatures exceeding 1000°C for up to 60 minutes. In certain exemplary embodiments, the aerogel materials or compositions of the present disclosure can have a high-temperature shrinkage, i.e., any combination of linear shrinkage, width shrinkage, thickness shrinkage, or dimensional shrinkage, of about 20% or less, about 15% or less, about 10% or less, about 6% or less, about 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, or a range between any two of these values.

[0207] In some exemplary embodiments, certain basic catalysts used to catalyze precursor reactions may introduce trace amounts of alkali metals into the aerogel composition. Trace levels of alkali, such as sodium or potassium, in the aerogel material, for example, 100 to 500 ppm, may adversely affect high-temperature shrinkage and thermal durability. However, without being bound by any particular mechanism or theory, aluminosilicate clay-based materials, such as halloysite or kaolin, may trap transient alkali, such as sodium or potassium, thereby reducing or eliminating the alkali's effect on shrinkage and thermal durability. In certain embodiments of the present disclosure, the aluminosilicate clay material is in a dehydrated form, such as metahalloysite or metakaolin. For example, aerogel materials or compositions containing metakaolin or metahalloysite in an amount greater than about 0.5 wt. % relative to the silica content may significantly reduce thermal shrinkage and thermal durability. In exemplary embodiments, the aerogel material or composition may contain metakaolin or metahalloysite in an amount ranging from about 0.5 wt. % to about 3.0 wt. % relative to the silica content.

[0208] FIG. 1 shows test data for samples of thermal control element or battery thermal management element materials according to embodiments disclosed herein, where a temperature of 650°C was applied to one surface, i.e., the hot side, of the thermal control element or battery thermal management element, and the temperature of the other surface, i.e., the cold side, of the thermal control element or battery thermal management element was measured over time. The control sample corresponds to the composition of Example 1, described in more detail below. Samples A, B, and C are embodiments of thermal control elements or battery thermal management elements disclosed herein that include kaolin as an additive. Sample A corresponds to the composition of Example 2, described in more detail below. Sample B corresponds to the composition of Example 4, below. Sample C corresponds to the composition of Example 3, below. As shown in FIG. 1, the composition including kaolin exhibits a cold side time of about 30 seconds to reach a temperature of 75°C, a cold side time of about 1 minute to reach a temperature of 120°C, a cold side time of about 90 seconds to reach a temperature of 150°C, and a cold side time of about 4 minutes to reach a temperature of 180°C. The unusually good performance using kaolin mineral as an additive in the temperature range below 200°C was surprising and unexpected.

[0209] Certain embodiments of the present disclosure provide methods for preparing reinforced aerogel compositions with fire-class performance. The fire-class compositions of these embodiments also possess sufficient hydrophobicity for use as thermal insulation in industrial environments, as measured by water absorption and low thermal conductivity, to help meet ever-demanding energy conservation needs. Simply adding additives, or even fire-class additives, will not work to achieve this combination of desirable properties. While various permutations and combinations or different additives can be tried to arrive at an optimized solution, such efforts are not always successful and present the risk of viable manufacturing with reproducible quality control for these desired properties. A key aspect of these embodiments is evaluating the thermal behavior (evaluated by thermogravimetry or differential scanning calorimetry) of a composition that would otherwise provide all desired properties except fire performance, and considering the fire-class additive to closely match the onset of thermal decomposition of the underlying composition, or alternatively, the temperature at which the majority of heat is released with the onset of pyrolysis of the fire-class additive, or the temperature at which the majority of heat is absorbed.

[0210] In certain embodiments, the desired combustion properties of the final composition may include not only intrinsic properties such as heat of combustion (ISO 1716), but also system combustion properties such as response to combustion performance per ISO 1182, where weight loss, furnace temperature rise, and flame duration are evaluated when exposed to a furnace at a temperature of about 750°C.

[0211] Fiber or OCMF-reinforced aerogel compositions may contain various components that add oxidizable organic content (fuel) to the system. Additionally, they may contain various other components that do not contribute fuel but may inhibit combustion when exposed to fire. Therefore, the combustion behavior of such systems cannot be predicted simply based on their components. In situations where multiple properties are desired, in certain embodiments, a composition should be achieved without regard to its fire-resistant properties, and the thermal performance of such a achieved composition should be evaluated to find the appropriate fire-class additive that imparts fire-resistant properties without compromising other properties intended by the starting composition.

[0212] In certain embodiments, the onset of thermal decomposition is a critical characteristic of the composition. In certain other embodiments, the temperature of peak heat release can be a critical characteristic for developing enhanced fire-resistant aerogel compositions. When multiple fuel components are present in a composition, as identified by multiple peaks in the DSC curve, such compositions perform well by matching the temperature of the enhanced aerogel composition's peak heat release with a fire-class additive that has an endothermic peak heat release temperature within 140°C, 120°C, 100°C, or 80°C of the peak heat release temperature of the enhanced aerogel composition. In many embodiments, the endothermic peak heat release temperature is within 50°C.

[0213] The disclosed aerogel materials and compositions have been shown to be highly effective as thermal insulating materials. However, the application of the disclosed methods and materials is not intended to be limited to insulation-related applications. The disclosed methods and materials can be applied to any system or application that benefits from the unique combination of properties or procedures provided by the disclosed materials and methods.

[0214] The following examples provide various non-limiting embodiments and properties of the present disclosure. In the following examples, the weight percent of additives is provided based on 100% being the total weight of the aerogel composition. Figures 1 and 2 illustrate the thermal control element or battery thermal management element that controls the warm behavior of the following examples. [Example]

[0215] A glass fiber-reinforced silica aerogel composition was produced according to the method disclosed above. The reinforced silica aerogel composition had a thickness of approximately 3 mm and contained 21.7 wt% synthetic amorphous silica, 12.2 wt% silica methyl silylate, 62.27 wt% fibrous glass, and 3.8 wt% iron oxide (Fe2O3). An 8-inch square sample of this composition was evaluated using the Hot Surface Performance Test at a 650°C hot surface. The cold surface temperature of the sample composition was measured over a period of time. For this sample composition, the cold surface time to reach 75°C was approximately 15 seconds, the cold surface time to reach 120°C was approximately 30 seconds, the cold surface time to reach 150°C was approximately 40 seconds, and the cold surface time to reach 180°C was approximately 1 minute. The data for this sample composition corresponds to the "Control" in the table in Figure 1. [Example]

[0216] A glass fiber-reinforced silica aerogel composition was produced according to the method disclosed above. The reinforced silica aerogel composition had a thickness of approximately 3 mm and contained 15.3 wt.% synthetic amorphous silica, 8.6 wt.% methylsilylated silica, 37.8 wt.% fibrous glass, and 38.3 wt.% kaolin. The target silica density was 0.07 g / cc. An 8-inch square sample of this composition was evaluated using the Hot Surface Performance Test at a 650°C hot surface. The cold surface temperature of the sample composition was measured over a period of time. For this sample composition, the cold surface time to reach 75°C was approximately 32 seconds, the cold surface time to reach 120°C was approximately 1 minute, the cold surface time to reach 150°C was approximately 90 seconds, and the cold surface time to reach 180°C was approximately 4 minutes. The compositional data for this sample corresponds to "A" in the table in Figure 1. [Example]

[0217] A glass fiber-reinforced silica aerogel composition was produced according to the method disclosed above. The reinforced silica aerogel composition had a thickness of approximately 3 mm and contained 15.3 wt.% synthetic amorphous silica, 8.6 wt.% methylsilylated silica, 37.8 wt.% fibrous glass, and 38.3 wt.% kaolin. The target silica density was 0.09 g / cc. An 8-inch square sample of this composition was evaluated using the Hot Surface Performance Test at a 650°C hot surface. The cold surface temperature of the sample composition was measured over a period of time. For this sample composition, the cold surface time to reach 75°C was approximately 38 seconds, the cold surface time to reach 120°C was approximately 68 seconds, the cold surface time to reach 150°C was approximately 102 seconds, and the cold surface time to reach 180°C was approximately 4 minutes. The compositional data for this sample corresponds to "C" in the table in Figure 1. [Example]

[0218] A glass fiber-reinforced silica aerogel composition was produced according to the method disclosed above. The reinforced silica aerogel composition had a thickness of approximately 3 mm and contained 15.3 wt% synthetic amorphous silica, 8.6 wt% methylsilylated silica, 37.8 wt% fibrous glass, and 38.3 wt% kaolin and ATH combination. The target silica density was 0.07 g / cc. An 8-inch square sample of this composition was evaluated using the Hot Surface Performance Test at a 650°C hot surface. The cold surface temperature of the sample composition was measured over a period of time. For this sample composition, the cold surface time to reach 75°C was approximately 36 seconds, the cold surface time to reach 120°C was approximately 1 minute, the cold surface time to reach 150°C was approximately 96 seconds, and the cold surface time to reach 180°C was approximately 3 minutes and 21 seconds. The compositional data for this sample corresponds to "B" in the table in Figure 1. [Example]

[0219] A glass fiber-reinforced silica aerogel composition was produced according to the method disclosed above. The reinforced silica aerogel composition had a thickness of approximately 3.5 mm and contained 21.7 wt.% synthetic amorphous silica, 12.2 wt.% silica methyl silylate, 62.27 wt.% fibrous glass, and 3.8 wt.% iron oxide (Fe2O3). An 8-inch square sample of this composition was evaluated using the Hot Surface Performance Test at a 650°C hot surface. The cold surface temperature of the sample composition was measured over a period of time. For this sample composition, the cold surface time to reach 75°C was approximately 13 seconds, the cold surface time to reach 120°C was approximately 22 seconds, the cold surface time to reach 150°C was approximately 29 seconds, and the cold surface time to reach 180°C was approximately 36 seconds. The data for this sample composition correspond to the "Control" in the table in Figure 2. [Example]

[0220] Sols of both methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) or polyethylsilicate (Silbond 40) were prepared separately by hydrolysis under acidic conditions in ethanol. The ratios and concentrations of the sol materials were adjusted to obtain a hydrophobic content of approximately 36 wt% MTES, resulting in aerogels with an organic content of approximately 8.0 wt% within the aerogel material. Silicon carbide (SiC) was incorporated into the combined sol at a weight percentage of at least 35 wt% relative to the silica content. The combined sols were then stirred for at least one hour.

[0221] Guanidine hydroxide (2M) was added to the combined sol at a concentration sufficient to target an aerogel density of approximately 0.07 to 0.085 g / cc. The catalyzed SiC-containing sol was cast onto the fiber-reinforced phase and allowed to gel. Immediately before and after gelation, the fiber-reinforced wet gel was subjected to a series of forming steps using a heavy stainless steel roller. Using a rigid, incompressible gauge block placed on the edge of the wet gel, the wet gel was repeatedly rolled up to four times to a controlled thickness of 3.0 mm. After curing at room temperature for up to one hour, the aerogel material was aged at 68°C for approximately 12 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent extracted with supercritical CO2 and then dried at 110°C for two hours.

[0222] The fiber-reinforced phase is approximately 250 g / m 2 The resulting reinforced silica aerogel composition was a uniform nonwoven material composed of textile-grade glass fibers (E-glass composition) approximately 5.6 mm thick and having a density of 1000 psi. The resulting reinforced silica aerogel composition was approximately 2.5 mm thick and consisted of approximately 44% aerogel (comprising approximately 28% synthetic amorphous silica and approximately 16% silica methylsilylate), 41% fibrous glass, and 15% silicon carbide, resulting in an expected material density of approximately 0.20 g / cc (given an aerogel density of 0.085 g / cc).

[0223] An 8-inch square sample of this composition was evaluated using the Hot Surface Performance Test on a 650°C hot surface. The cold surface temperature of the sample composition was measured over a period of time. For this example sample composition, the cold surface time to reach 75°C was approximately 13 seconds, the cold surface time to reach 120°C was approximately 24 seconds, the cold surface time to reach 150°C was approximately 31 seconds, and the cold surface time to reach 180°C was approximately 42 seconds. The data for this example sample composition corresponds to "E" in the table in Figure 2. [Example]

[0224] Sols of both methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) or polyethylsilicate (Silbond 40) were prepared separately by hydrolysis under acidic conditions in ethanol. The ratios and concentrations of the sol materials were adjusted to obtain a hydrophobic content of approximately 36 wt% MTES, resulting in aerogels with an organic content of approximately 8.0 wt% within the aerogel material. Silicon carbide (SiC) was incorporated into the combined sol at a weight percentage of at least 35 wt% relative to the silica content. The combined sols were then stirred for at least one hour.

[0225] Guanidine hydroxide (2M) was added to the combined sol at a concentration sufficient to target an aerogel density of approximately 0.07 to 0.085 g / cc. The catalyzed SiC-containing sol was cast onto the fiber-reinforced phase and allowed to gel. Immediately before and after gelation, the fiber-reinforced wet gel was subjected to a series of forming steps using a heavy stainless steel roller. Using a rigid, incompressible gauge block placed on the edge of the wet gel, the wet gel was repeatedly rolled up to four times to a controlled thickness of 2.0 mm. After curing at room temperature for less than one hour, the aerogel material was aged at 68°C for approximately 12 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0226] The fiber-reinforced phase is approximately 250 g / m 2 The resulting reinforced silica aerogel composition was a uniform nonwoven material composed of textile-grade glass fibers (E-glass composition) approximately 5.6 mm thick and having a density of 1.0 g / cc. The resulting reinforced silica aerogel composition was approximately 2.0 mm thick and consisted of approximately 36% aerogel (comprising approximately 23% synthetic amorphous silica and approximately 13% silica methylsilylate), 51% fiber, and 13% silicon carbide, resulting in an expected material density of approximately 0.20 g / cc (given an aerogel density of 0.085 g / cc).

[0227] An 8-inch square sample of this composition was evaluated using the Hot Surface Performance Test on a 650°C hot surface. The cold surface temperature of the sample composition was measured over a period of time. For this example sample composition, the cold surface time to reach 75°C was approximately 11 seconds, the cold surface time to reach 120°C was approximately 21 seconds, the cold surface time to reach 150°C was approximately 31 seconds, and the cold surface time to reach 180°C was approximately 39 seconds. The data for this example sample composition corresponds to "D" in the table in Figure 2.

[0228] Samples of this composition were evaluated in compression. The deformation of the sample was measured to obtain the stress-strain relationship of the sample. The data for this analysis is shown in Figure 3. [Example]

[0229] Sols of both methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) or polyethylsilicate (Silbond 40) were prepared separately by hydrolysis under acidic conditions in ethanol. The ratios and concentrations of the sol materials were adjusted to obtain a hydrophobic content of approximately 36 wt% MTES, resulting in aerogels with an organic content of approximately 8.0 wt% within the aerogel material. Silicon carbide (SiC) was incorporated into the combined sol at a weight percentage of at least approximately 10 wt% relative to the silica content. The combined sols were then stirred for at least one hour.

[0230] Guanidine hydroxide (2M) was added to the combined sol at a concentration sufficient to target an aerogel density of approximately 0.07 to 0.085 g / cc. The catalyzed SiC-containing sol was cast onto the fiber-reinforced phase and allowed to gel. Immediately before and after gelation, the fiber-reinforced wet gel was subjected to a series of forming steps using a heavy stainless steel roller. Using a rigid, incompressible gauge block placed on the edge of the wet gel, the wet gel was repeatedly rolled up to four times to a controlled thickness of 3.0 mm. After curing at room temperature for up to one hour, the aerogel material was aged at 68°C for approximately 12 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent extracted with supercritical CO2 and then dried at 110°C for two hours.

[0231] The fiber-reinforced phase is approximately 225 g / m 2 The resulting reinforced silica aerogel composition was a uniform nonwoven material composed of textile-grade glass fibers (E-glass composition) approximately 4 mm thick with a density of 1000 psi. The resulting reinforced silica aerogel composition was approximately 2.25 mm thick and consisted of approximately 39% aerogel (comprising approximately 25% synthetic amorphous silica and approximately 14% silica methylsilylate), 57% fibrous glass, and 4% silicon carbide, yielding an expected material density of approximately 0.16 g / cc (given an aerogel density of 0.075 g / cc).

[0232] An 8-inch square sample of this composition was evaluated using the Hot Surface Performance Test on a 650°C hot surface. The cold surface temperature of the sample composition was measured over a period of time. For this example sample composition, the cold surface time to reach 75°C was approximately 9 seconds, the cold surface time to reach 120°C was approximately 19 seconds, the cold surface time to reach 150°C was approximately 25 seconds, and the cold surface time to reach 180°C was approximately 34 seconds. Data for this example sample composition is shown in the chart in Figure 4.

[0233] The above advantages, and those that will become apparent from the above description, are efficiently achieved. Because certain changes can be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense.

[0234] It is also to be understood that the following claims are intended to cover all of the general and specific features of the invention described herein, and all statements of the scope of the invention that may be said to lie therebetween as a matter of language.

Claims

1. A battery thermal management member, a first thermal protection layer; and at least one elastic layer comprising one or more organic materials; the first thermally protective layer has a thermal conductivity of less than about 65 mW / mK; The at least one thermal protection layer maintains at least one surface of the resilient layer below a decomposition temperature of at least one of the organic materials.

2. The battery thermal management member of claim 1 , wherein the first thermally protective layer is disposed adjacent to the at least one resilient layer.

3. The battery thermal management member of claim 1 or 2, wherein the first thermally protective layer is disposed in contact with the at least one resilient layer.

4. The battery thermal management member of claim 1 , further comprising a second thermal protection layer.

5. 5. The battery thermal management member of claim 4, wherein the first thermal protective layer and the second thermal protective layer are disposed on opposite sides of the at least one resilient layer.

6. 7. The battery thermal management member of claim 4 or claim 6, wherein at least one of the first thermal protective layer and the second thermal protective layer is disposed in contact with the at least one resilient layer.

7. The battery thermal management member of claim 1 , wherein the resilient layer comprises a compressible material.

8. 8. The battery thermal management member of claim 7, wherein the compressible material has a chemical decomposition temperature greater than about 200°C.

9. 9. The battery thermal management member of claim 7 or 8, wherein the temperature of chemical decomposition of the compressible material is greater than about 240°C.

10. 10. The battery thermal management member of claim 7, wherein the temperature of chemical decomposition of the compressible material is greater than about 280°C.

11. 11. The battery thermal management member of claim 7, wherein the temperature of chemical decomposition of the compressible material ranges from about 200°C to about 300°C.

12. 12. The battery thermal management member of claim 7, wherein the temperature of chemical decomposition of the compressible material is greater than about 300°C.

13. 13. The battery thermal management member of any of claims 7-12, wherein the temperature of chemical decomposition of the compressible material is greater than about 350°C.

14. 14. The battery thermal management member of any of claims 7-13, wherein the temperature of chemical decomposition of the compressible material ranges from about 300°C to about 400°C.

15. 15. The battery thermal management member of any of claims 7-14, wherein the compressible material comprises a material selected from the group consisting of siloxanes, polyolefins, polyurethanes, phenolics, melamines, cellulose acetate, and polystyrenes.

16. 16. The battery thermal management member of any of claims 1 to 15, wherein the first thermal protection layer comprises an aerogel composition.

17. 5. The battery thermal management component of claim 4, wherein the second thermal protective layer comprises an aerogel composition.

18. 18. The battery thermal management component of claim 16 or claim 17, wherein the aerogel composition comprises a reinforcing material.

19. 20. The battery thermal management member of claim 18, wherein the reinforcing material is present in the aerogel composition.

20. 20. The battery thermal management member of claim 18 or claim 19, wherein the reinforcing material comprises fibers.

21. 21. The battery thermal management member of claim 20, wherein the fibers are selected from the group consisting of discrete fibers, woven materials, nonwoven materials, needled nonwovens, battings, webs, mats, felts, and combinations thereof.

22. 22. The battery thermal management member of any of claims 1-21, wherein the aerogel of the aerogel composition comprises an inorganic, organic, or inorganic / organic hybrid material.

23. 23. The battery thermal management component of any of claims 1 to 22, wherein the aerogel composition is a silica aerogel composition.

24. 24. The battery thermal management member of claim 1, wherein the first thermal protective layer or the second thermal protective layer comprises a material selected from the group consisting of mica, microporous silica, ceramic fiber, mineral wool, and combinations thereof.

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