Composite

Abstract

Disclosed in the present specification are a composite and a heat-absorbing device, which are applied to products or devices in an abnormal state or in which the abnormal state is likely to occur, and thus can effectively respond to heat, an ignition and an explosion in the abnormal state. For example, the composite and the heat-absorbing device are applied to articles including a plurality of the products or devices, and thus can respond to abnormal heat generation, an explosion and an ignition occurring in any one device or product, and prevent or minimize propagation of the heat generation, the explosion and the ignition to other adjacent devices or products. The composite and the heat-absorbing device also exhibit excellent handling and storage stability. In addition, the present specification can provide a use of the composite and the heat-absorbing device.

Description

composite materials

[0001] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2024-0103452, filed August 2, 2024, and Republic of Korea Patent Application No. 10-2024-0174258, filed November 28, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present specification discloses a composite material, a heat absorbing device comprising the composite material, and uses of the composite material and the heat absorbing device.

[0003] The importance of technology to manage heat generated from products is increasing, but it is a difficult problem to manage, control, and manage heat in products composed of multiple heat-generating elements (heat-generating elements).

[0004] For example, it is very important to prevent the so-called TR (Thermal Runaway) or TP (Thermal Propagation) phenomenon that occurs in battery modules or battery packs. A battery module or battery pack includes multiple battery cells or multiple battery modules, which are positioned relatively adjacent to each other. In such a structure, the phenomenon in which abnormal heat generation, ignition, and / or explosion occurring in one battery cell and / or battery module is transmitted in a chain reaction to other adjacent battery cells is called the TR or TP phenomenon. The chain reaction of ignition or explosion caused by this TR or TP phenomenon must be managed from a safety perspective.

[0005] The present specification discloses composite materials, heat absorbing devices, and their uses. The purpose of the present specification is to disclose composite materials and heat absorbing devices that can be applied to products or components that have the potential for abnormal heat generation, ignition, and / or explosion during operation, storage, and / or maintenance, thereby effectively counteracting such heat generation, ignition, and explosion.

[0006] For example, the composite materials and heat absorbing devices disclosed herein can be applied to articles comprising multiple of the above products or elements to respond to abnormal heat generation, explosion, and / or ignition occurring in one of the elements or products, and prevent or minimize the spread of such heat generation, explosion, and / or ignition to other adjacent elements or products.

[0007] The present specification also aims to disclose a composite material and a heat absorbing device having excellent handling and storage stability. The present specification also aims to disclose uses of the composite material and the heat absorbing device.

[0008] Among the properties mentioned in this specification, properties that are affected by temperature are properties measured at room temperature, unless otherwise specified.

[0009] The term room temperature means a natural temperature that has not been artificially heated or cooled, for example, a temperature within the range of about 10°C to 30°C, for example, a temperature of about 23°C or about 25°C.

[0010] The unit of temperature referred to in this specification is Celsius (℃), unless otherwise specified.

[0011] Among the properties mentioned in this specification, properties affected by pressure are properties measured at atmospheric pressure, unless otherwise specified.

[0012] The term atmospheric pressure refers to natural pressure that has not been artificially pressurized or depressurized, and is usually a pressure in the range of about 700 mmHg to 800 mmHg.

[0013] Among the properties mentioned in this specification, properties affected by humidity are properties measured at room temperature and pressure without artificially controlling humidity, unless otherwise specified.

[0014] The present specification discloses a composite material.

[0015] The term composite refers to a material containing two or more components.

[0016] The above composite material may include an inorganic gel.

[0017] The present specification also discloses a heat absorbing device comprising the composite material.

[0018] The above heat absorbing device may include a case having a sealed space inside and a composite material existing in the sealed space inside.

[0019] The case is a container for holding the composite material. The case has a sealed space inside. The case having a sealed space inside means that the sealed space is formed inside the case, or that a certain space exists inside the case, and although the space is not sealed, the case exists so that the sealed space can be formed by sealing the open portion.

[0020] The term "abnormal condition" as used herein refers to a condition in which abnormal heat generation, ignition and / or explosion occurs during the operation, storage and / or maintenance of any product or component, or in which there is a possibility of such abnormal heat generation, ignition and / or explosion occurring.

[0021] In this specification, the term normal state refers to the normal operation, storage and / or maintenance state of any product or device other than the above abnormal state.

[0022] The above-mentioned sealed space refers to a space formed so that the components of the composite material, etc., do not substantially leak out to the outside under normal conditions. In one example, the case may have a WVTR (Water Vapor Transmission Rate) within a predetermined range described below, and the sealed space may be substantially entirely surrounded by a case having the WVTR (Water Vapor Transmission Rate).

[0023] The above-mentioned sealed space has a vent area. The term "vent area" may refer to an area that exists to maintain a sealed state under normal conditions, but is opened under abnormal conditions to allow the discharge of substances within the space. Such a vent area may be formed in the manner described below.

[0024] In one example, the case may have a water vapor transmission rate (WVTR) within a predetermined range. For example, at least a portion of the case forming the sealed space may have a water vapor transmission rate (WVTR) within a predetermined range. For example, the upper limit of the WVTR of the above case may be about 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05, 0.01, 0.005, or 0.001, and the lower limit may be about 0, 0.1, 0.2, 0.3, 0.4, or 0.5. The WVTR is within a range that is less than or equal to any one upper limit arbitrarily selected from the upper limits listed above; Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By having such a WVTR, storage stability for a substance existing inside the sealed space can be secured, and the heat absorbing device can more efficiently exhibit the intended extinguishing or endothermic action. The unit of the WVTR (Water Vapor Transmission Rate) is g / m2·day. The WVTR is evaluated according to the standard of ASTM F1249 under the conditions of 38°C and 100% relative humidity.

[0025] The above-mentioned heat absorbing device is configured to maintain a vaporizable substance contained in the composite material in the sealed space in a normal state and to release the vaporizable substance or its vaporized substance to the outside in an abnormal state.

[0026] This action is explained assuming that the above heat absorbing device is applied to a battery module.

[0027] Fig. 1 is a schematic diagram of a case where the heat absorption device (S) is applied to a battery module. As shown in Fig. 1, the battery module can be configured by arranging a plurality of battery cells (11, 12, 13, 14, 15, 16) adjacent to each other, and the heat absorption device (S) can be arranged between battery cells (for example, between 12 and 13 and / or between 14 and 15 in Fig. 1).

[0028] The above heat absorbing device (S) maintains volatile substances, etc., inside it in a normal state. When an abnormal state occurs, the internal substance of the heat absorbing device (S) is ejected through the vent area (dashed arrow in Fig. 1), and the internal substance ejected in this way can respond to heat generation and / or flames, etc. in the abnormal state. In Fig. 1, a case is described where the internal substance is ejected from both the upper and lower directions of the heat absorbing device (S), but the direction of the ejection is not limited to Fig. 1. The direction of the ejection may be one direction of the heat absorbing device (S), or may be two or more directions.

[0029] In order for the heat absorbing device to effectively perform the above function in an abnormal state, it is required that the volatile substances existing inside the case in a normal state be stably maintained, that the internal substances be able to be quickly discharged to the outside when an abnormal state occurs, and that the volatile substances existing inside the case in an abnormal state be able to be discharged to the outside in a vaporized state as much as possible so that they are consumed.

[0030] For the heat absorbing device to effectively perform the above function under ideal conditions, the vaporization rate of the vaporizable substance must be maintained appropriately. If the vaporizable substance vaporizes at an appropriate rate, the pores of the internal inorganic gel can be prevented from collapsing due to changes in surface tension, etc. following heat absorption by the vaporizable substance.

[0031] The heat absorbing device disclosed in this specification can satisfy the above requirements.

[0032] The above-mentioned heat absorbing device explains the principle by which the above-mentioned function is performed.

[0033] Fig. 2 shows only the heat absorbing device (S) in Fig. 1 separately. In a configuration such as Fig. 1, if abnormal heating, abnormal ignition, and / or abnormal explosion occurs in at least one of the battery cells adjacent to the heat absorbing device (S), a certain level of heat or more is instantaneously applied to the heat absorbing device, as indicated by the solid arrow in Fig. 2. In the sealed space inside the case (1001) of the heat absorbing device in Fig. 2, as indicated by the dotted arrow, volatile substances are randomly propagated in all directions within the space. At this time, if the WVTR of the portion forming the sealed space of the case (1001) is within the aforementioned range, the vaporized gas cannot be released to the outside, and therefore, the inside of the case (1001) becomes very high-pressure. At this time, when the vent area (1002) of the case is configured to open instantaneously at a high pressure above a certain level, the vent area (1002) is opened instantaneously at the high pressure state, and the gas inside is quickly discharged to the outside through the opened vent area (1002).

[0034] When the WVTR of the case is high, the pressure inside the case (1001) may not effectively increase in an abnormal state, so that the vent area (1002) may not be opened effectively, or even when the vent area (1002) is opened, the internal pressure may not sufficiently increase, so that the internal gas may not be completely discharged to the outside and exhausted, or the discharge speed may not be properly secured.

[0035] By keeping the WVTR of the case low, the storage stability of the internal material under normal conditions can also be effectively secured.

[0036] The method for forming the above-mentioned vent area (1002) is not particularly limited. The vent area can be formed by designing a certain area of ​​the case forming the sealed space to be opened when a certain level of pressure and / or heat is applied. For example, if a certain area of ​​the case forming the sealed space is configured to have lower strength than other areas, the area having the lower strength can be opened due to increased internal pressure. In addition, a method of forming the sealed space through sealing using a hot melt material or the like so that opening occurs by melting at a predetermined temperature can also be used. Alternatively, the vent area can be formed by making only a certain area of ​​the case forming the sealed space thinner than other areas. Such methods for forming the vent area can be easily adopted by those skilled in the art.

[0037] For example, when the heat absorbing device is applied to a battery module or pack, for convenience of application, the case may be a square case, pouch-shaped case, and / or cylindrical case having the same shape as the battery cell. In such cases, a vent area may also be formed by controlling the bonding strength of the cover forming a sealed space in the square or cylindrical case.

[0038] The above case can be constructed using a known material as long as it can satisfy the aforementioned WVTR, and the material can have a single-layer structure or a single-layer structure of two or more layers.

[0039] For example, the case can be formed using a material capable of exhibiting a WVTR in the above range among suitable organic and / or inorganic layers.

[0040] As the organic layer, for example, a known polymer film or sheet can be used. Examples of the organic film include a cellulose-based polymer film; a COP (cyclo olefin copolymer) film; an acrylic polymer film; a polyolefin film; a PVA (polyvinyl alcohol) film; a PVC (poly(vinyl chloride)) film, a PES (poly ether sulfone) film; a PEEK (polyetheretherketon) film; a PPS (polyphenylsulfone) film; a PEI (polyetherimide) film; a PEN (polyethylenemaphthatlate) film; a PET (poly(ethylene terephthalate)) film; a PI (polyimide) film; a PSF (polysulfone) film and / or a PAR (polyarylate) film.

[0041] For example, the inorganic layer may be a metal layer, a metal oxide layer, a metal nitride layer, or a metal oxynitride layer. For example, the inorganic layer may be a metal layer, a metal oxide layer, a metal nitride layer, or a metal oxynitride layer including at least one selected from the group consisting of In, Sn, Pb, Au, Cu, Ag, Zr, Hf, Zn, Al, Si, La, Ti, and Ni. For example, a foil, sheet, or film of the material may be applied, or a layer formed by depositing the metal layer, the metal oxide layer, the metal nitride layer, or the metal oxynitride layer on an appropriate substrate may be used.

[0042] The material forming the case may be a single layer selected from the inorganic layer and organic layer, or a multilayer structure in which two or more of the layers are laminated.

[0043] The thickness of the above-mentioned inorganic layer and / or organic layer is selected in consideration of the desired properties such as WVTR and is not particularly limited. For example, the lower limit of the thickness may be about 1, 5, 10, 15, 20, 25 or 30, and the upper limit may be about 5,000, 4,000, 3,000, 2,000, 1,000, 500, 200, 150, 100, 90, 80, 70, 60, 50, 40 or 30. The unit of the thickness is μm. The thickness is within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above. Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0044] The above heat absorbing device may include additional components to enable the above operation to be performed more effectively.

[0045] For example, the heat absorbing device may additionally include a heat conductive layer. This heat conductive layer may be located at an appropriate location within the heat absorbing device, for example, the heat conductive layer may be located between the case and the composite material described below within the heat absorbing device.

[0046] Fig. 3 is an example of a case in which the heat-conducting layer (2001) is added to the heat-absorbing device of Fig. 2. The heat-conducting layer may be located between the case (1001) and the composite material as shown in Fig. 3, but is not limited thereto in terms of location. The heat-conducting layer may be located in other locations, such as inside the case, and the number of heat-conducting layers may be one or two or more.

[0047] The term thermally conductive layer refers to a layer having a thermal conductivity (at 20°C) within the range described below. The lower limit of the thermal conductivity (at 20°C) of the thermally conductive layer may be about 15, 18, 20, 50, 100, 150, 200, 250, 300, 350, or 400, and the upper limit may be about 2,000, 1,500, 1,000, 900, 800, 700, 600, 500, 400, 300, 200, 100, or 50. The thermal conductivity is within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. The unit of the thermal conductivity is W / mK.

[0048] The type of thermally conductive layer is not particularly limited as long as it possesses the above-mentioned thermal conductivity. Typically, metal materials with excellent thermal conductivity can be used as thermally conductive layers. For example, layers made of metal materials such as aluminum, gold, pure silver, tungsten, copper, nickel, or platinum can be applied.

[0049] There is no special limitation on the thickness of the thermal conductive layer, and an appropriate thickness can be set in consideration of the specifications of the heat absorption device, etc. For example, the lower limit of the thickness of the thermal conductive layer may be about 1, 5, 10, 15, 50, 75, or 90, and the upper limit may be about 500, 400, 300, 200, 100, 50, 40, or 30. The unit of the thickness is μm. The thickness may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0050] As shown in Fig. 3, in some cases, heat generated in an abnormal state may not be uniformly applied to the heat absorber, but may be locally applied only to a certain area. However, in order for the volatile substances inside the heat absorber to quickly vaporize and achieve a high-pressure state, the heat in the abnormal state must be uniformly applied to the heat absorber. In the case where a heat conductive layer exists, even if the heat in the abnormal state is locally applied, the heat can be quickly and efficiently transferred to the entire heat absorber, thereby enabling the aforementioned extinguishing action of the heat absorber to occur quickly and efficiently.

[0051] The present specification discloses a composite material. Such a composite material may be present in a sealed space of a case of the heat absorbing device described above.

[0052] The above composite material can be provided to exhibit at least one endothermic peak and at least one exothermic peak in a thermogravimetric differential calorimetry analysis.

[0053] Materials designed to withstand high heat and flames typically encountered under abnormal conditions are designed to exhibit at least an endothermic peak, while minimizing exothermic peaks. However, composites formulated to exhibit at least one exothermic peak at a specific point have been shown to more effectively control high heat and flames under abnormal conditions.

[0054] The method for performing the above thermogravimetric differential calorimetry analysis is described in the Test Example 1 of this specification.

[0055] The above composite material can exhibit at least two or more exothermic peaks in the thermogravimetric differential calorimetry. For example, the lower limit of the number of exothermic peaks exhibited by the composite material can be about 1, 2, or 3, and the upper limit can be about 10, 9, 8, 7, 6, 5, 4, or 3. The number of exothermic peaks can be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0056] The above exothermic peak can be confirmed within a predetermined temperature range. For example, the exothermic peak may appear within any one of a temperature range of 350°C to 530°C (hereinafter, referred to as the first exothermic peak temperature range) and a temperature range of 560°C to 640°C (hereinafter, referred to as the second exothermic peak temperature range) in the analysis. For example, one or more exothermic peaks may appear in any one of the first and second exothermic peak temperature ranges, or one or more exothermic peaks may appear in both of the first and second exothermic peak temperature ranges.

[0057] For example, in a case where multiple exothermic peaks are confirmed, the lower limit of the temperature range in which the exothermic peak (the first exothermic peak) confirmed in the lowest temperature range among the exothermic peaks appears may be about 350°C, 370°C, 390°C, or 410°C, and the upper limit may be about 430°C, 420°C, 410°C, or 400°C. The temperature range may be a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0058] In the case where multiple exothermic peaks are confirmed, the lower limit of the temperature range in which the exothermic peak (second exothermic peak) confirmed in the highest temperature range among the exothermic peaks appears may be about 560°C, 570°C, 580°C, 590°C, or 600°C, and the upper limit may be about 640°C, 630°C, 620°C, 610°C, 600°C, 590°C, or 580°C. The temperature range may be a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0059] An additional exothermic peak (a third exothermic peak) may be identified between the first exothermic peak and the second exothermic peak.

[0060] The lower limit of the temperature range in which the third exothermic peak is confirmed may be about 430°C, 440°C, 450°C, 460°C, 470°C, or 480°C, and the upper limit may be about 530°C, 520°C, 510°C, 500°C, 490°C, 480°C, 470°C, or 460°C. The temperature range may be a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0061] Accordingly, the composite material may exhibit two or more or two exothermic peaks in the first exothermic peak temperature range, which may be the first and third exothermic peaks.

[0062] The lower limit of the number of endothermic peaks exhibited by the above composite in the above thermogravimetric differential calorimetry may be about 1 or 3, and the upper limit may be about 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1. The number of endothermic peaks may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0063] The lower limit of the temperature range indicated by the above endothermic peak may be about 260°C, 265°C, 270°C, 275°C, 280°C, or 285°C, and the upper limit may be about 330°C, 320°C, 310°C, 300°C, 290°C, 280°C, or 270°C. The temperature range may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0064] The lower limit of the heat absorption indicated by the above-mentioned endothermic peak may be about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55, and the upper limit may be about 900, 800, 700, 600, 500, 400, 300, 200, 100, 80, 60, 40, or 20. The unit of the heat absorption is kJ / kg. The heat absorption may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0065] The above composite material or the heat absorbing device including the same may have an absolute value of △T in the following equation 1 within a predetermined range.

[0066] [Formula 1]

[0067] △T = 100 × (T2 - T1) / T1

[0068] In Equation 1, T2 is the thickness of the composite or heat absorbing device confirmed after maintaining the composite or heat absorbing device at -30°C for 20 hours, and T1 is the thickness of the composite or heat absorbing device confirmed at 25°C before maintaining the composite or heat absorbing device at -30°C for 20 hours.

[0069] The method for measuring △T of Equation 1 is described in Test Example 3 of this specification. The thicknesses T1 and T2 are each an average of the thicknesses measured at three arbitrary points of the composite material or heat absorbing device according to the contents described in Test Example 3.

[0070] In one example, the upper limit of the absolute value of the thickness change rate △T may be about 10%, 9%, 8%, 7%, 6%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.9%, 0.8%, 0.7%, or 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, or 0.1%, and the lower limit may be about 0%, 0.5%, 1%, 1.5%, 2%, or 2.5%, or 3%. The △T is within a range that is equal to or less than any one upper limit arbitrarily selected from the upper limits listed above; Or it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. The above △T may be a positive or negative number.

[0071] By ensuring that the thickness change rate of the composite or heat absorbing device is within the above range, for example, the composite or heat absorbing device can be prevented from causing damage to other components of the device. For example, if the thickness change rate is large when the temperature decreases in the environment in which the composite or heat absorbing device is applied, the stress generated by the expansion or contraction of the composite or heat absorbing device may adversely affect other adjacent devices.

[0072] The above composite material may include an inorganic gel.

[0073] These inorganic gels can stably maintain volatile substances in composites under normal conditions, while effectively discharging them under abnormal conditions. Furthermore, the inorganic gels exhibit appropriate buffering, insulation, and heat-insulating properties, thereby enabling the composite and heat-absorbing device to effectively respond to abnormal conditions.

[0074] The above characteristics can be secured by controlling the material of the inorganic gel and the degree and form of gelation.

[0075] The above-mentioned inorganic gel may be, for example, an oxide network formed by a so-called sol-gel process. This oxide network may include a network in which inorganic elements are connected via oxygen atoms. As the inorganic elements, one or more selected from the group consisting of silicon, titanium, zirconium, niobium, tantalum, molybdenum, and tungsten may be exemplified. If the inorganic element is silicon, the inorganic gel may be called silica gel.

[0076] The content of the above-mentioned inorganic gel can be appropriately controlled depending on the purpose. For example, the lower limit of the content of the above-mentioned inorganic gel based on the total weight of the composite may be about 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt% or 6.5 wt%, and the upper limit may be about 20 wt%, 15 wt%, 10 wt%, 8 wt%, 6 wt%, 4 wt% or 2 wt%. The above-mentioned ratio may be within a range that is less than or equal to any upper limit arbitrarily selected from the above-mentioned upper limits and greater than or equal to any lower limit arbitrarily selected from the above-mentioned lower limits.

[0077] In another example, the lower limit of the content of the inorganic gel relative to 100 parts by weight of the volatile material may be about 0.001 parts by weight, 0.005 parts by weight, 0.01 parts by weight, 0.05 parts by weight, 0.1 parts by weight, 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight or 2.5 parts by weight, and the upper limit may be about 100 parts by weight, 95 parts by weight, 90 parts by weight, 85 parts by weight, 80 parts by weight, 75 parts by weight, 70 parts by weight, 65 parts by weight, 60 parts by weight, 55 parts by weight, 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 parts by weight, 30 parts by weight, 25 parts by weight, 20 parts by weight, 15 The weight ratio may be about 10 parts, 5 parts, 4 parts, 3 parts, 2 parts, or 1 part. The ratio may be within a range that is less than or equal to an upper limit arbitrarily selected from the upper limits listed above; or within a range that is equal to or greater than an lower limit arbitrarily selected from the lower limits listed above; or within a range that is equal to or greater than an lower limit arbitrarily selected from the lower limits listed above and equal to or less than an upper limit arbitrarily selected from the upper limits listed above.

[0078] The inorganic gel disclosed herein can stably maintain the volatile substances described below in a composite material under normal conditions, while effectively discharging them under abnormal conditions. Furthermore, the inorganic gel exhibits appropriate buffering, insulation, and heat-insulating properties, thereby enabling the composite material and heat-absorbing device to effectively respond to abnormal conditions.

[0079] The above-mentioned inorganic gel can be formed in the manner described below.

[0080] The above properties can be secured by controlling the material of the above-mentioned inorganic gel and the degree and form of gelation.

[0081] The composite material may further comprise a vaporizable material along with the inorganic gel. The term "vaporizable material" refers to a material that vaporizes at a given temperature. Such a vaporizable material may exist in a liquid state at room temperature (25°C). Such a vaporizable material may be used to reduce abnormal heat, such as through heat exchange, under abnormal conditions, or to eliminate flames generated by ignition and / or explosion. Such a vaporizable material may rapidly vaporize under abnormal conditions, thereby increasing the pressure in a confined space, opening the vent area, and allowing the material to be discharged to the outside through the opened vent area.

[0082] As the above-mentioned volatile substance, any substance that can be vaporized and is non-flammable may be used without any special restrictions. For example, the above-mentioned volatile substance may be a solvent having a freezing point and / or boiling point within a certain range.

[0083] For example, the lower limit of the freezing point of the volatile substance may be about -5°C, -4°C, -3°C, -2°C, -1°C, or 0°C, and the upper limit may be about 10°C, 9°C, 8°C, 7°C, 6°C, 5°C, 4°C, 3°C, or 2°C. The freezing point may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The freezing point is a freezing point under 1 atm.

[0084] In order for the above-mentioned volatile substance to effectively respond to the above-mentioned heat generation, ignition and / or explosion, it may be advantageous for the above-mentioned volatile substance to be vaporized at least by the heat generated by the above-mentioned heat generation, ignition and explosion, and for this purpose, the boiling point of the above-mentioned volatile substance may be controlled.

[0085] The lower limit of the boiling point of the above-mentioned volatile substance may be about 80°C, 85°C, 90°C, or 95°C, and the upper limit may be about 120°C, 115°C, 110°C, or 105°C. The boiling point may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The boiling point is a boiling point under 1 atm.

[0086] Any volatile substance having a freezing point and / or boiling point within the above range and being non-flammable may be selected and used without any special restrictions. A representative example of such a volatile substance is water, and thus water can be used as the volatile substance. However, the types of applicable volatile substances are not limited to the above.

[0087] The lower limit of the proportion of the volatile material in the composite may be, for example, about 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt% or 80 wt%, and the upper limit may be about 95 wt%, 90 wt%, 85 wt%, 80 wt%, 75 wt%, 70 wt%, 65 wt%, 60 wt%, 55 wt%, 50 wt%, 45 wt% or 40 wt%. The proportion is within a range that is greater than or equal to any lower limit arbitrarily selected from among the lower limits listed above; Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0088] The above ratio is a ratio confirmed when the total weight of the composite material is 100 wt%.

[0089] For example, if the volatile substance is water, the content can be analyzed according to the following equation 3.

[0090] [Formula 3]

[0091] W(%) = [(ab) / a] × 100

[0092] In Equation 3, b is the weight measured after drying the composite at a temperature of 150°C for 24 hours, and a is the weight of the composite before drying it at a temperature of 150°C for 24 hours. The drying can be performed using, for example, a convection oven.

[0093] The above composite may additionally include an ionic compound.

[0094] These ionic compounds may be derived from a substance added to adjust the freezing point of the composite, a substance added as a polymerization catalyst for forming the inorganic gel, and / or a substance added to form polymerization conditions that cause the inorganic gel to exhibit desired properties.

[0095] For example, a composite including an inorganic gel formed under polymerization conditions formed by the addition of the ionic compound may exhibit appropriate buffering properties. In addition, the mobility of the vaporizable material molecules adjusted by the addition of the ionic compound may enable the vaporizable material to exhibit an appropriate vaporization rate in the above-described state. In addition, the freezing point of the composite adjusted by the addition of the ionic compound may suppress expansion of the vaporizable material at low temperatures, thereby solving problems such as a decrease in stability due to an increase in internal pressure caused by an increase in the thickness of the composite, and / or a decrease in stability due to an increase in pressure caused by unnecessary vapor generation and subsequent volume expansion at high temperatures.

[0096] Ionic compounds can be used that have a certain level of solubility in the above-mentioned volatile substances or water. The degree of freedom in selecting an ionic compound with an appropriate solubility increases with the amount of the ionic compound added. Accordingly, an amount that secures the desired freezing point can be selected without impairing the fire extinguishing function and while improving it.

[0097] The lower limit of the solubility of the above ionic compound in water 100 at 0℃ may be about 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210 or 215, and the upper limit may be about 1000, 900, 800, 700, 600, 500, It can be 400, 300, 250, 245, 240, 235, 230, 225, 220, 215, 210, 205, 200, 195, 190, 185, 180, 175, 170, 165, 160, 155, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, or 30. The solubility may be within a range that is less than or equal to any one of the upper limits arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any one of the lower limits arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any one of the lower limits arbitrarily selected from the lower limits listed above and less than or equal to any one of the upper limits listed above. The solubility is the weight of an ionic compound that can be maximally dissolved in 100 g of water at 0°C, and the unit of the solubility is g. The solubility may be defined as the amount of a sample that can be maximally dissolved in 100 g of water at 0°C according to ASTM E1148-02.

[0098] The lower limit of solubility of the above ionic compound in 100 g of water at 25°C is 70, 75, 80, 85, 90, 95, 100, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 225, 230, 235, 240, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, It can be around 310, 315 or 320, and its upper limit is 1000, 900, 800, 700, 600, 500, 400, 350, 345, 340, 335, 330, 325, 320, 315, 310, 305, 300, 295, 290, 280, 275, 270, 265, 260, 255, 250, 245, 240, 235, 230, 225, 220, 215, 210, 205, 200, 195, 190, 185, 180, 175, 170, 165, It can be about 160, 155, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105 or 100. The solubility can be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The solubility is the weight of an ionic compound that can be maximally dissolved in 100 g of water at 25°C, and the unit of the solubility is g. The solubility can be defined as the amount of a sample that can be maximally dissolved in 100 g of water at 25°C according to ASTM E1148-02.

[0099] The category of ionic compounds above includes substances that are ionic in themselves or can produce ions, such as salts, acids, or bases.

[0100] In one example, the ionic compound may be exemplified by at least one selected from the group consisting of potassium salts, sodium salts, magnesium salts, and ammonium salts. The ionic compound may be at least one selected from the group consisting of formic acid, acetate, carbonate, and / or sulfate. Specific examples of the ionic compound include sodium acetate (CH3COONa), sodium formate (HCOONa), potassium acetate (CH3COOK), potassium formate (HCOOK), and calcium formate ((HCOO )2Ca ), magnesium formate ((HCOO)2Mg), potassium carbonate (K2CO3), and ammonium sulfate ((NH4)2SO4) may be used.

[0101] In another example, the ionic compound may be an acid and / or base added as a catalyst for the polymerization described below.

[0102] For example, a potassium-based salt or an ammonium-based salt may be used as the ionic compound. Alternatively, an ammonium-based salt may be used as the freezing point depressant. In such cases, the ionic compound may include one or more selected from the group consisting of potassium acetate, potassium formate, potassium chloride, potassium hydroxide, ammonium carbonate, and ammonium sulfate.

[0103] Ionic compounds have the following formula 2 △T f can be included so that it is within a certain range. △T in Equation 2 below fis a value reflecting the degree of freezing point adjustment that can be achieved by adding the ionic compound, and this value can be adjusted within a range that ensures the above-described effects, i.e., appropriate adjustment of the mobility of the vaporizable substance molecules, formation of an inorganic gel of the desired network, and stability at high or low temperatures.

[0104] [Formula 2]

[0105] △T f = K f× M×I

[0106] K in Equation 2 f is the freezing point depression constant of the volatile substance, M is the molal concentration of the ionic compound with respect to the volatile substance, and I is the number of moles of ions produced by complete dissociation of 1 mole of the ionic compound.

[0107] K in Equation 2 f is the freezing point depression constant of a volatile substance, and its unit is K / m or K / ℃. For example, if the volatile substance is water, the Kf is 1.86.

[0108] M in Equation 2 is the molal concentration of the ionic compound, which is the molal concentration relative to the volatile substance. Therefore, M is the number of moles of the ionic compound present per 1 kg of the volatile substance in the composite.

[0109] I in Equation 2 is the number of ions (moles) formed by 1 mole of the ionic compound when the ionic compound is dissociated, and in this case, dissociation means a state in which the ionic compound is completely dissociated.

[0110] △T in Equation 2 fThe lower limit of may be, for example, 1, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24, and the upper limit may be, for example, 50, 45, 40, 35, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12 or 11. The above △T f It may be within a range that is greater than or equal to any one of the lower limits arbitrarily selected from the lower limits listed above; or within a range that is less than or equal to any one of the upper limits arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any one of the lower limits arbitrarily selected from the lower limits listed above and less than or equal to any one of the upper limits arbitrarily selected from the upper limits listed above. △T in Equation 2 f The unit is ℃. Within the above range, the desired effects, such as appropriate adjustment of the mobility of the vaporizable substance molecules, formation of an inorganic gel of the desired network, and securing stability at high or low temperatures, can be obtained.

[0111] The above ionic compound can exhibit a boiling point or decomposition temperature within a predetermined range. Through this, the above appropriate heat absorption performance and heat blocking performance can be realized.

[0112] In one example, the lower limit of the boiling point or decomposition temperature of the ionic compound may be 300°C, 320°C, 340°C, 360°C, 380°C, 400°C, 420°C, 440°C, 460°C, 480°C, or 500°C, and the upper limit may be 1500°C, 1450°C, 1400°C, 1350°C, 1300°C, 1250°C, 1200°C, 1150°C, 1100°C, 1050°C, or 1000°C. The range may be within a range that is equal to or greater than any arbitrarily selected lower limit among the lower limits listed above; or within a range that is equal to or greater than any arbitrarily selected lower limit among the lower limits listed above and equal to or less than any arbitrarily selected upper limit among the upper limits listed above.

[0113] The above composite may further include inorganic fibers. These inorganic fibers may serve to ensure that the composite exhibits the aforementioned cushioning properties and, in some cases, may serve to support some or all of the components, such as the volatile substances, described above.

[0114] As inorganic fibers, for example, inorganic fibers commonly used in the formation of insulating materials can be used, such as so-called glass fibers and / or ceramic fibers, fibers mixed with high and low molecules, etc. Such inorganic fibers can exist in the form of, for example, woven or nonwoven fabrics or paper. The category of woven or nonwoven fabrics may also include objects referred to as wool or blankets.

[0115] For example, as the inorganic fiber, ceramic paper, ceramic paper using an organic / inorganic binder, binder-free fiber, ceramic fiber, glass fiber, glass felt, basalt fiber, basalt felt, aramid fabric, silica felt, oxpan carbon felt, carbon fiber felt, and / or melamine fiber can be used, and an organic binder can be used. When the inorganic fiber is used, the insulation property is excellent, and the sol is easily absorbed, so that materials such as gels and heat absorbents can be evenly positioned within the substrate, thereby increasing stability.

[0116] The properties of the above inorganic fibers can be adjusted according to the purpose.

[0117] For example, the lower limit of the tensile strength of the inorganic fiber may be about 0.01 MPa, 0.05 MPa, or 0.1 MPa, and the upper limit may be about 10 MPa, 9 MPa, 8 MPa, 7 MPa, 6 MPa, 5 MPa, 4 MPa, 3 MPa, 2 MPa, 1 MPa, or 0.5 MPa. The tensile strength may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0118] For example, the lower limit of the compressive strength of the inorganic fiber may be about 1 kPa, 5 kPa, 10 kPa, 50 kPa, 100 kPa, or 150 kPa, and the upper limit may be about 1,000 kPa, 900 kPa, 800 kPa, 700 kPa, 600 kPa, 500 kPa, 400 kPa, 300 kPa, or 200 kPa. The compressive strength may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. At this time, the compressive strength may be measured as the compressive strength when compressed to 50% of the initial thickness of the inorganic fiber.

[0119] For example, the lower limit of the Young's modulus of the inorganic fiber may be about 0.1 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, or 3 MPa, and the upper limit may be about 20 MPa, 18 MPa, 16 MPa, 14 MPa, 12 MPa, 10 MPa, 8 MPa, 6 MPa, or 4 MPa. The Young's modulus may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0120] The inorganic fibers, when included in the composite, may exhibit one or more of the tensile strength, compressive strength, and Young's modulus within the above range. Thus, for example, if the inorganic fibers are included in the composite in the form of the woven or nonwoven fabric, the woven or nonwoven fabric may exhibit one or more of the tensile strength, compressive strength, and Young's modulus within the above range. The tensile strength, compressive strength, and Young's modulus may be measured according to the KS K ISO 9073-3 standard.

[0121] It is possible to form a composite having the desired properties by applying inorganic fibers exhibiting tensile strength, compressive strength and / or Young's modulus in the above range.

[0122] The lower limit of the density of the above-mentioned inorganic fiber may be about 0.01, 0.05, or 0.1, and the upper limit may be about 10, 8, 6, 4, 2, 1, 0.5, or 0.3. The density may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The unit of the density is g / cm 3 am.

[0123] The inorganic fibers, when included in the composite, can exhibit a density within the above range. Thus, for example, if the inorganic fibers are included in the composite in the form of a woven or nonwoven fabric, the woven or nonwoven fabric can exhibit the above density.

[0124] When the above-mentioned inorganic fiber is included in the form of a woven fabric or a non-woven fabric, the thickness of the woven fabric or the non-woven fabric may be selected within a range capable of exhibiting the above-described characteristics. For example, the lower limit of the thickness may be about 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, or 3, and the upper limit may be about 100, 50, 30, 10, 8, 6, or 4. The thickness may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The unit of the thickness is mm.

[0125] The above-mentioned inorganic fibers may be present in the composite material in an appropriate ratio. For example, the lower limit of the weight ratio of the inorganic fiber to 100 parts by weight of the volatile material may be about 0.5 parts by weight, 1 part by weight, 5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 10 parts by weight, 20 parts by weight, or 25 parts by weight, and the upper limit may be about 200 parts by weight, 180 parts by weight, 160 parts by weight, 140 parts by weight, 120 parts by weight, 100 parts by weight, 95 parts by weight, 90 parts by weight, 85 parts by weight, 80 parts by weight, 75 parts by weight, 70 parts by weight, 65 parts by weight, 60 parts by weight, 55 parts by weight, 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 parts by weight, 30 parts by weight, 25 parts by weight, 20 parts by weight, or 15 parts by weight. The above ratio may be within a range that is less than or equal to any one of the upper limits arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any one of the lower limits arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any one of the lower limits arbitrarily selected from the lower limits listed above and less than or equal to any one of the upper limits arbitrarily selected from the upper limits listed above.

[0126] In another example, the lower limit of the content of the inorganic fiber based on 100 wt% of the composite may be about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt% or 12 wt%, and the upper limit may be about 30 wt%, 25 wt%, 20 wt%, 18 wt%, 17 wt%, 16 wt%, 15 wt%, 14 wt%, 13 wt% or 12 wt%. The ratio may be within a range that is less than or equal to any one upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any one lower limit arbitrarily selected from the lower limits listed above. Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0127] When the above-described inorganic fibers and inorganic gel exist simultaneously, the inorganic gel may be attached to the inorganic fibers, or the inorganic gel and the inorganic fibers may exist in a state of being entangled with each other. For example, as described below, the above-described structure can be realized by performing the gelation process in the presence of the inorganic fibers, thereby allowing the composite to exhibit desired properties and perform the desired function more effectively.

[0128] The above composite material includes the above components and, if necessary, may include additional components (e.g., opacifiers (e.g., TiO2, Fe2O3 and / or SiC, etc.) and / or flame retardants (MC, Ultracarb, Al(OH)3, Mg(OH)2, etc.).

[0129] The present specification discloses a method for preparing the above composite material or inorganic gel.

[0130] For example, the method for producing the inorganic gel includes a step of polymerizing a precursor solution containing an inorganic gel precursor and a vaporizable material.

[0131] The polymerization described above is a process in which relatively low-molecular-weight substances, such as monomers or oligomers, form chains or networks to form high-molecular-weight components. In this case, the monomer or oligomer may be the precursor. Furthermore, there are no particular limitations on the specific method by which the polymerization is performed. For example, if the inorganic gel precursor is a condensation precursor described below, the polymerization process may be a so-called sol-gel process.

[0132] The composition of the precursor solution can be adjusted to form the desired inorganic gel and composite.

[0133] As the precursor, for example, a metal alkoxide can be used. This precursor is a condensation precursor and can form an inorganic gel through the sol-gel process. Specifically, the metal alkoxide may be one or more alkoxides selected from the group consisting of silicon, titanium, zirconium, niobium, tantalum, molybdenum, and tungsten. The lower limit of the number of carbon atoms present in the alkoxide may be about 4, 6, 8, or 10, and the upper limit may be about 20, 18, 16, 14, 12, 10, or 8. The above carbon number may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. As the precursor, for example, a component called sodium silicate may be used, and such a component can form silica gel as an inorganic gel.

[0134] As the above-mentioned volatile material, components such as water described above can be used.

[0135] The composition of the precursor solution can be adjusted to form the desired inorganic gel and composite.

[0136] For example, the content of the vaporizable substance in the precursor solution can be adjusted. For example, the lower limit of the content of the vaporizable substance in the precursor solution can be about 30 wt%, 40 wt%, 50 wt%, 60 wt%, or 65 wt%, and the upper limit can be about 95 wt%, 90 wt%, 85 wt%, 80 wt%, 75 wt%, 70 wt%, 65 wt%, 60 wt%, 55 wt%, or 50 wt%. The content can be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0137] The lower limit of the weight ratio of the precursor to 100 parts by weight of the vaporizable substance in the precursor solution may be about 1 part by weight, 3 parts by weight, 5 parts by weight, 7 parts by weight, 10 parts by weight, 15 parts by weight, or 20 parts by weight, and the upper limit may be about 100 parts by weight, 90 parts by weight, 80 parts by weight, 70 parts by weight, 60 parts by weight, 50 parts by weight, 40 parts by weight, 30 parts by weight, 25 parts by weight, 20 parts by weight, 15 parts by weight, or 10 parts by weight. The content may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and is equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0138] The above-described precursor solution may be formulated to exhibit a pH within a predetermined range. For example, the lower limit of the pH of the above-described precursor solution may be about 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, or 7, and the upper limit may be about 14, 13, 12, 11, 10, 9, 8, or 7. The pH may be within a range that is equal to or greater than any lower limit arbitrarily selected from the above-described lower limits and equal to or less than any upper limit arbitrarily selected from the above-described upper limits.

[0139] To adjust the pH, the precursor solution may additionally contain a catalyst. This catalyst may be an ionic compound. There is no particular limitation on the type of applicable catalyst, and for example, an acid catalyst or a base catalyst applicable to a general sol-gel process may be used. Examples of such acid catalysts include one or a mixture of two or more selected from hydrochloric acid, sulfuric acid, fluorosulfuric acid, nitric acid, phosphoric acid, acetic acid, hexafluorophosphoric acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid, and examples of base catalysts include, but are not limited to, alkaline catalysts such as sodium hydroxide, ammonium hydroxide, or ammonium chloride.

[0140] The content of the catalyst can be controlled within a range where the above-mentioned pH can be achieved. For example, the lower limit of the molal concentration of the catalyst (i.e., the number of moles of catalyst present per 1 kg of the vaporizable substance) based on the vaporizable substance in the precursor solution may be about 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.5, 1, or 1.5, and the upper limit may be about 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.8, 0.6, or 0.4. The molal concentration may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and is equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0141] The above-mentioned precursor solution may additionally contain an ionic compound in addition to the catalyst. This ionic compound may be added to adjust the molecular energy of the vaporizable substance and thereby its mobility. Examples of the ionic compound include the aforementioned potassium salts, sodium salts, magnesium salts, and / or ammonium salts.

[0142] The content of all ionic compounds present in the precursor solution, including the catalyst, can be adjusted. Adjusting this content controls the fluidity of the vaporizable material, and this controlled fluidity can affect the polymerization efficiency of the precursor, thereby forming the desired inorganic gel at a specified polymerization temperature.

[0143] For example, the ionic compound has △T of the above-mentioned formula 2 f can be added so that it is within a certain range. In this case, K in Equation 2 f is the freezing point depression constant of the vaporizable substance in the above-mentioned precursor solution, M is the molal concentration of the ionic compound with respect to the vaporizable substance in the above-mentioned precursor solution, and I is the number of moles of ions generated by complete dissociation of 1 mole of the ionic compound.

[0144] △T of Equation 2 in the bulb solution f The lower limit of may be, for example, 1, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24, and the upper limit may be, for example, 50, 45, 40, 35, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12 or 11. The above △T f It may be within a range that is greater than or equal to any one of the lower limits arbitrarily selected from the lower limits listed above; or within a range that is less than or equal to any one of the upper limits arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any one of the lower limits arbitrarily selected from the lower limits listed above and less than or equal to any one of the upper limits arbitrarily selected from the upper limits listed above. △T in Equation 2 f The unit is ℃. Within the above range, the desired effects, such as appropriate adjustment of the mobility of the vaporizable substance molecules, formation of an inorganic gel of the desired network, and securing stability at high or low temperatures, can be obtained.

[0145] The bulb solution may contain any necessary ingredients in addition to the above ingredients.

[0146] For example, the polymerization of the precursor solution may be performed in the presence of the inorganic fibers. The inorganic fibers also affect the polymerization efficiency of the precursor. In such a case, the precursor solution may include the inorganic fibers described above.

[0147] The lower limit of the weight ratio of the inorganic fiber to 100 parts by weight of the volatile material in the bulb solution may be about 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, or 25 parts by weight, and the upper limit may be about 100 parts by weight, 90 parts by weight, 80 parts by weight, 70 parts by weight, 60 parts by weight, 50 parts by weight, 40 parts by weight, 30 parts by weight, 20 parts by weight, or 15 parts by weight. The weight ratio may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, while being less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0148] The temperature for polymerization of the above-mentioned bulb solution can be controlled. This controlled temperature is the above-mentioned △T f It contributes to the formation of an inorganic gel of the desired shape by linking with an ionic compound having a value of .

[0149] For example, the lower limit of the polymerization temperature may be about 10°C, 15°C, 20°C, 25°C, 30°C, or 35°C, and the upper limit may be about 50°C, 45°C, 40°C, 35°C, 30°C, or 25°C. The polymerization temperature may be within a range that is equal to or greater than any arbitrarily selected lower limit among the lower limits listed above, while being less than or equal to any arbitrarily selected upper limit among the upper limits listed above.

[0150] In order to form the desired inorganic gel and composite, the polymerization of the precursor or the prepolymer of the precursor may be performed in the presence of inorganic fibers. For this purpose, the polymerization may be performed in multiple stages. For example, the manufacturing method may include a first stage (primary polymerization) of polymerizing the precursor solution to obtain a prepolymer, and a second stage (secondary polymerization) of polymerizing the precursor or prepolymer in the presence of the inorganic fibers to obtain an inorganic gel. The precursor solution applied to the first polymerization may not include the inorganic fibers. That is, the first polymerization may be performed in the absence of inorganic fibers, and the second polymerization of the second stage may be performed in the presence of inorganic fibers. That is, after the first polymerization, the polymer may be mixed with the inorganic fibers, and further polymerization may be performed. The precursor of the second stage may refer to a precursor that did not participate in the polymerization during the first polymerization to form a prepolymer.

[0151] The polymerization temperature, polymerization time, and / or mixing conditions of the first step may be adjusted.

[0152] The lower limit of the polymerization temperature of the first step may be about 10°C, 15°C, 20°C, 25°C, 30°C, or 35°C, and the upper limit may be about 50°C, 45°C, 40°C, 35°C, 30°C, or 25°C. The polymerization temperature may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, while being less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0153] The above first step can be performed while stirring the precursor solution at an appropriate speed. In this process, the lower limit of the stirring speed can be about 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm, and the upper limit can be about 2,000 rpm, 1,500 rpm, 1,000 rpm, 800 rpm, 600 rpm, 400 rpm, or 300 rpm. The stirring speed can be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0154] The lower limit of the time for performing the above first polymerization may be about 1 second, 5 seconds, 10 seconds, 30 seconds, 1 minute, 5 minutes, 10 minutes, or 15 minutes, and the upper limit may be about 60 minutes, 55 minutes, 50 minutes, 45 minutes, 40 minutes, 35 minutes, 30 minutes, 25 minutes, 20 minutes, 15 minutes, 10 minutes, 8 minutes, 6 minutes, 4 minutes, 2 minutes, 1 minute, or 30 seconds. The time may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0155] By forming a primary polymer (a mixture of a prepolymer or a prepolymer and a precursor) under the above conditions and performing secondary polymerization, the desired composite material can be formed.

[0156] The above primary polymer can be further polymerized secondaryally to form an inorganic gel. As described above, the secondary polymerization can be performed in the presence of the inorganic fibers. That is, after the primary polymerization, the inorganic fibers and the primary polymer are mixed so as to satisfy the ratio described above (ratio of inorganic fibers to 100 parts by weight of the volatile material), and then further polymerization is performed to effectively form the desired inorganic gel.

[0157] The above secondary polymerization can be performed at an appropriate temperature.

[0158] For example, the lower limit of the polymerization temperature may be about 10°C, 15°C, 20°C, or 25°C, and the upper limit may be about 40°C, 35°C, 30°C, or 25°C. The temperature may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0159] By maintaining the mixture of the primary polymer and the inorganic fiber at the above temperature during the secondary polymerization, the desired inorganic gel can be obtained.

[0160] The composite can be prepared by mixing the inorganic gel formed in this manner with other components of the desired composite. These components may be mixed with the inorganic gel after the inorganic gel is prepared, mixed into the precursor solution prior to the preparation of the inorganic gel, or performed at an appropriate point during the preparation of the inorganic gel.

[0161] After manufacturing the composite material as described above, it can be placed within a case to form a heat absorbing device. The composite material can be manufactured and placed within the case, or the entire or partial manufacturing process of the composite material can be performed within the case to form the heat absorbing device. For example, the heat absorbing device and the composite material can be manufactured simultaneously by pre-placing the inorganic fibers within the case, injecting the primary polymer, followed by additional polymerization, and then introducing additional components after polymerization, if necessary.

[0162] The present specification also discloses an electronic equipment or device to which the above heat absorbing device is applied.

[0163] The type of electronic equipment or device is not particularly limited. For example, the composite material or heat-absorbing device may be applied to equipment or devices that pose a risk of abnormal heat generation, ignition, and / or explosion during operation, maintenance, and / or storage, and where such abnormal phenomena must be controlled.

[0164] Examples of the above equipment or devices include batteries. In particular, in battery modules comprised of multiple battery cells, it is crucial to prevent abnormal heat generation, ignition, and / or explosion from occurring in one battery cell from spreading to adjacent battery cells.

[0165] The present specification discloses a battery module including the above heat absorbing device.

[0166] Such a battery module may basically include a plurality of battery cells; and the heat absorbing device disposed between the battery cells.

[0167] As long as the above-mentioned heat absorbing device is applied, the specific configuration of the battery module, for example, the type of the battery cell, etc., is not particularly limited, and any known material may be applied. For example, any known pouch-shaped, square-shaped, or cylindrical battery cell may be applied as the battery cell.

[0168] The method for manufacturing the above battery module is not particularly limited, and for example, a method may be used in which a heat absorbing device in the form of a battery cell is manufactured as described above, and then the heat absorbing device is positioned at a required location during the manufacturing process of the battery module.

[0169] The present specification discloses a composite material and a heat absorbing device that can be applied to a product or device that is in an abnormal state or has the potential to experience such an abnormal state, and can effectively respond to heat, ignition, and explosion during such an abnormal state. For example, the composite material and heat absorbing device can be applied to an article comprising multiple products or devices, and can respond to abnormal heat generation, explosion, and ignition occurring in one of the devices or products, and prevent or minimize the spread of such heat generation, explosion, and ignition to other adjacent devices or products. The composite material and heat absorbing device also exhibit excellent handling and storage stability. The present specification can also provide uses for the composite material and heat absorbing device.

[0170] Figure 1 is an exemplary cross-sectional view of a battery module to which a heat absorbing device is applied.

[0171] Figures 2 and 3 are exemplary drawings for explaining the operating principle of the heat absorbing device.

[0172] Figure 4 is an exemplary drawing of an outer shell for packaging a composite material.

[0173] Fig. 5 is an example of a device for obtaining a temperature-time graph.

[0174] Figure 6 shows the results of the thermogravimetric differential heat analysis of the composite material of the example.

[0175] Figure 7 shows the results of the thermogravimetric differential heat analysis of the composite material of the comparative example.

[0176] The composite material and the like are specifically described with reference to the following examples, but the scope of the composite material and the like is not limited by the following examples.

[0177]

[0178] Example 1.

[0179] A mixture was prepared by mixing primary distilled water (W), potassium acetate (AC) (molar mass: 98.15 g / mol), hydrochloric acid (molar mass: 36.46 g / mol) aqueous solution (H) (hydrochloric acid concentration: 33 wt%), and liquid sodium silicate (S) in a weight ratio of 48.3:30:1.7:5 (W:AC:H:S), and a silica sol was prepared. As the liquid sodium silicate, No. 3 (KS) (No. 3 KS) of Youngil Chemical Co., Ltd. (Na2O content: about 9 to 10 wt%, SiO2 content: about 28 to 30 wt%, sodium silicate molar ratio (= 1.032 (SiO2 weight) / (Na2O weight)): about 3.1 to 3.3) was used.

[0180] The pH of the above mixture was approximately 6 to 7.

[0181] The molal concentration of the hydrochloric acid in the above mixture based on the first distilled water was approximately 0.31, and the molal concentration of potassium acetate was approximately 6.18. In addition, the △T of the following equation 1 by the hydrochloric acid in the above mixture f was approximately 1.16, and the △T of the following equation 1 by the potassium acetate f was about 23.

[0182] [Formula 1]

[0183] △T f = K f × M × I

[0184] K in Equation 1 f is the freezing point depression constant of the above-mentioned primary distilled water, which is approximately 1.86 K / m, M is the molal concentration of each ionic compound (hydrochloric acid or potassium acetate), and I is the number of moles of ions generated when 1 mole of the above-mentioned ionic compound is completely dissociated.

[0185] The above silica sol was prepared by stirring the mixture at room temperature (about 23°C) at a speed of about 500 rpm for about 2 minutes.

[0186] Next, ceramic paper (HT Ceramic Fiber Paper, 190 kg / m 3 , 2 mm) was impregnated with the silica sol and gelation was performed to manufacture a composite. During the impregnation, the ratio (S:CP) of the weight (S) of the liquid sodium silicate added during the preparation of the mixture and the weight (CP) of the ceramic paper was approximately 5:15.

[0187] The above gelation was carried out at room temperature (approximately 23°C) after the impregnation, so that gelation could proceed 10 minutes after the silica sol was impregnated into the ceramic paper. The water content in the composite was approximately 52.4 wt%.

[0188] The above water content was confirmed according to the following formula 3.

[0189] [Formula 3]

[0190] Water content = 100 × (W - Wd) / W

[0191] In Equation 3, W is the weight of the composite, and Wd is the weight of the composite after drying it in a convection oven at 150°C for 24 hours.

[0192] In order to manufacture the heat absorbing device, two outer shells (121, 122) as shown in Fig. 4 were prepared. The outer shells are made of Al material with a thickness of about 3 mm each, and the WVTR (Water Vapor Transmission Rate) is about 0 g / m 2· It was about day. The above WVTR was evaluated according to the standard of ASTM F1249 under the conditions of 38℃ and 100% relative humidity. The composite material was placed in the concave portion (I) of the lower outer shell (122), and after covering it with the upper outer shell (121), the connection portion (S) of the upper outer shell (121) and the lower outer shell (122) was fused at a temperature of about 200℃ to manufacture a heat absorbing device.

[0193]

[0194] Example 2.

[0195] A mixture (pH: about 6 to 7) was prepared by mixing primary distilled water (W), potassium acetate (AC) (molar mass: 98.15 g / mol), hydrochloric acid (molar mass: 36.46 g / mol) aqueous solution (H) (hydrochloric acid concentration: 33 wt%), and liquid sodium silicate (S) in a weight ratio of 52.7:32:1.8:5.5 (W:AC:H:S), and a silica sol was prepared. The liquid sodium silicate used was the same as that in Example 1.

[0196] The molal concentration of the hydrochloric acid in the above mixture based on the first distilled water was about 0.3, and the molal concentration of potassium acetate was about 6.05. △T of the above equation 1 by the hydrochloric acid in the above mixture f was approximately 1.12, and the △T of the above formula 1 by the potassium acetate f was about 22.5.

[0197] The above silica sol was prepared in the same manner as in Example 1.

[0198] Next, basalt fiber (Basalt Fiber, 100 kg / m) 3 , 2 mm) was impregnated with the silica sol and gelation was performed to prepare a composite. The gelation was performed in the same manner as in Example 1, except that the ratio (S:BF) of the weight (S) of the liquid sodium silicate added during the preparation of the mixture and the weight (BF) of the basalt fiber was about 5.5:8. The water content in the composite was about 57.2 wt%. A heat absorbing device was manufactured using the composite in the same manner as in Example 1.

[0199]

[0200] Example 3.

[0201] Distilled water (W), potassium acetate (AC) (molar mass: 98.15 g / mol), hydrochloric acid (molar mass: 36.46 g / mol) aqueous solution (H) (hydrochloric acid concentration: 33 wt%), and liquid sodium silicate (S) were mixed in a weight ratio of 53.7:32:1.8:5.5 (W:AC:H:S) to prepare a mixture (pH: about 6 to 7), and a silica sol was prepared. The liquid sodium silicate was the same as that used in Example 1.

[0202] The molal concentration of the hydrochloric acid based on the primary distilled water in the above mixture was approximately 0.3, and the molal concentration of potassium acetate was approximately 5.94. △T of the above equation 1 by the hydrochloric acid in the above mixture f was approximately 1.10, and the △T of the above formula 1 by the potassium acetate f was approximately 22.09. The silica sol was prepared in the same manner as in Example 1.

[0203] Next, glass fiber (100 kg / m) 3 , 5 mm) was impregnated with the silica sol and gelation was performed to prepare a composite. The gelation was performed in the same manner as in Example 1, except that the ratio (S:GF) of the weight (S) of the liquid sodium silicate added during the preparation of the mixture and the weight (GF) of the glass fiber was approximately 5.5:7. The water content in the composite was approximately 58.2 wt%. A heat absorbing device was manufactured using the composite in the same manner as in Example 1.

[0204]

[0205] Example 4.

[0206] A mixture was prepared by mixing primary distilled water (W), potassium acetate (AC) (molar mass: 98.15 g / mol), NaOH (molar mass: 39.997 g / mol) aqueous solution (N) (NaOH concentration: 33 wt%), HCl (molar mass: 36.46 g / mol) aqueous solution (H) (HCl concentration: 33 wt%), and liquid sodium silicate (S) in a weight ratio of 58:21:0.1:1.5:5 (W:AC:N:H:S), and a silica sol was prepared. The liquid sodium silicate was the same as that used in Example 1.

[0207] The pH of the above mixture was approximately 7 to 8.

[0208] In the above mixture, the molal concentration of the NaOH based on the first distilled water was about 0.01, the molal concentration of the HCl was about 0.23, and the molal concentration of potassium acetate was about 3.62. In the above mixture, the △T of the above equation 1 by the NaOH f was approximately 0.05, and the △T of the above equation 1 by the above HCl f was approximately 0.86, and the △T of the above formula 1 by the potassium acetate f was approximately 13.49. The silica sol was prepared in the same manner as in Example 1.

[0209] Next, the ceramic paper used in Example 1 was impregnated with the silica sol and gelation was performed to produce a composite. In this process, the impregnation was performed so that the ratio (S:CP) of the weight (S) of the liquid sodium silicate added during the preparation of the mixture and the weight (CP) of the ceramic paper was approximately 5.5:14.4.

[0210] The above gelation was performed in the same manner as in Example 1. The water content in the composite was approximately 62.1 wt%.

[0211] A heat absorbing device was manufactured in the same manner as in Example 1 using the above composite material.

[0212]

[0213] Comparative Example 1

[0214] A composite was manufactured by mixing the ceramic paper (CP) and water (W) applied in Example 1 at a weight ratio of 84:16 (W:CP).

[0215]

[0216] Comparative Example 2

[0217] A composite was manufactured by mixing the basalt fiber (BF) and water (W) applied in Example 2 at a weight ratio of 91:9 (W:BF).

[0218]

[0219] Comparative Example 3

[0220] A composite was manufactured by mixing the glass fiber (GF) and water (W) applied in Example 3 at a weight ratio (W:GF) of 92:8.

[0221]

[0222] Test Example 1.

[0223] Thermogravimetric differential calorimetry was performed using an analytical instrument (SDT 650). Approximately 5±1 mg of the composite was loaded into the SDT open pan of the analytical instrument. Subsequently, air was injected into the instrument at a rate of 0.5 mL / min, and the temperature was increased from 50°C to 1,000°C at a heating rate of 10°C / min. The thermogravimetric differential calorimetry was performed, and the normalized heat flow converted into the mass of the analyzed sample was derived in the temperature range.

[0224] Figures 6 and 7 are drawings showing the results of the above analysis.

[0225] As shown in the drawing, the composite material of the example exhibited one endothermic peak and three exothermic peaks, but in the comparative example, no peak was observed or one exothermic peak (Comparative Example 1) was observed.

[0226] Table 1 below lists the temperatures at which exothermic and endothermic peaks appear in each example and comparative example. In addition, the heat absorption in Table 1 below is a value obtained by integrating the interval between the left on-set point and the right on-set point of the endothermic peak in the example.

[0227] Example Comparative Example 1234123 Endothermic peak confirmation temperature (℃) 289 288 286 269 --- Exothermic peak confirmation temperature (℃) 39 44 17 41 0 40 65 36 --- Exothermic peak confirmation temperature (℃) 47 5 47 9 48 0 455 --- Exothermic peak confirmation temperature (℃) 59 7 6 0 0 60 65 80 --- Endothermic amount (kJ / kg) 55.1 9 25.6 26 17.5 ---

[0228] Test Example 2.

[0229] A heating plate (5000), an insulation board (2000), and a cooling plate (3000) were prepared. As shown in Fig. 5, an insulation board (2000) was laminated on the cooling plate (3000), and a temperature measuring device (thermal coupler) (4000) was installed on the insulation board (2000). The temperature measuring device (thermal coupler) (4000) was positioned so that the surface of the device (4000) and the surface of the insulation board (2000) formed the same horizontal surface. A groove was formed on the surface of the insulation board (2000), and the temperature measuring device (4000) was inserted into the groove to match the height. The insulation board (1000) was used as an Incera Board 10T product from HITEMS.

[0230] The sample (1000) to be measured (width: 7.5 cm, length: 7.5 cm) was placed on an insulating board (2000) and a temperature measuring device (4000), and the temperature of the heating plate (5000) was stabilized at 700°C. Then, the sample (1000) was pressed by the heating plate (5000) maintained at a temperature of 700°C, and the temperature change was confirmed by the temperature measuring device (4000). Before pressurizing by the heating plate (5000), if the temperature of the temperature measuring device (4000) was 50°C or higher, the sample was waited until the temperature dropped below 50°C, and then pressurizing by the heating plate (5000) was performed. During the above process, the temperature of the cooling plate (3000) was maintained at a level of 20°C to 30°C.

[0231] The above pressurization was performed at a pressure of approximately 50 kPa.

[0232] Table 2 summarizes the time to reach 180°C as confirmed by the test results. The time to reach 180°C is the time required from the time when pressurization with the heating plate (5000) begins in the above process until the temperature of 1800 is confirmed by the temperature measuring device (4000).

[0233] Example Comparative Example 1234123180℃ Reaching Time 66524882181416

[0234]

[0235]

[0236] Test Example 3.

[0237] The thickness of the heat absorber was measured at room temperature (approximately 25°C). The thickness was obtained by measuring the thickness of three points on the heat absorber under a pressure of 2 kPa using a measuring probe and averaging the results. The three points were formed so that there was at least a 2 cm gap between them. The thickness measured above was defined as T1 in Equation 1 below.

[0238] After that, the heat absorbing device whose thickness T1 was measured was placed in a convection oven, and the internal temperature was set to -30°C. After the internal temperature reached the set temperature (-30°C), it was maintained at that state for 20 hours. Thereafter, the heat absorbing device was taken out from the convection oven, and the thickness of the heat absorbing device was measured at room temperature (approximately 25°C) within 1 minute. This thickness was defined as T2 in Equation 1 below, and the measurement method was the same as for T1.

[0239] △T in Equation 1 was used as the thickness change rate.

[0240] [Formula 1]

[0241] △T = 100 × (T2 - T1) / T1

[0242] The thickness change rate △T measured in the above manner is summarized and described in Table 3 below.

[0243] Comparative Example 1234123△T(%)0.8-0.10.61.18.17.67.8

Claims

1. flammable substances; and Contains inorganic gel, A composite material exhibiting at least one endothermic peak and at least one exothermic peak in thermogravimetric differential calorimetry.

2. A composite material exhibiting at least two multiple exothermic peaks in the first paragraph.

3. A composite material according to claim 1 or 2, wherein the endothermic peak is confirmed in a temperature range of 260°C to 330°C.

4. A composite material according to any one of claims 1 to 3, wherein the exothermic peak appears within any one of a temperature range of 350°C to 530°C and a temperature range of 560°C to 640°C.

5. In the fourth paragraph, a composite material in which the exothermic peaks appear in the temperature range of 350°C to 530°C and the temperature range of 560°C to 640°C, respectively.

6. A composite material according to any one of claims 1 to 5, which exhibits two or more exothermic peaks in a temperature range of 350°C to 530°C.

7. A composite material according to any one of claims 1 to 6, wherein the content of the volatile material is in the range of 40 to 90 wt%.

8. A composite material according to any one of claims 1 to 7, wherein the volatile material is water.

9. A composite material according to any one of claims 1 to 8, wherein the inorganic gel is silica gel.

10. A composite material further comprising inorganic fibers according to any one of claims 1 to 9.

11. In the 10th paragraph, the inorganic fiber is a composite material existing in the form of woven fabric, nonwoven fabric or paper.

12. A composite material according to claim 10 or 11, wherein the inorganic gel is attached to the inorganic fiber, or the inorganic gel and the inorganic fiber are entangled with each other.

13. In any one of the first to 12th clauses, △T of the following formula 1 f Composite further comprising an ionic compound so that the molecular weight is within the range of 1 to 50: [Formula 1] △T f = K f× M×I K in Equation 1 f is the freezing point depression constant of the volatile substance, M is the molal concentration of the ionic compound with respect to the volatile substance, and I is the number of moles of ions produced when 1 mole of the ionic compound is completely dissociated.

14. A composite material according to claim 13, wherein the ionic compound is at least one selected from the group consisting of potassium salts, sodium salts, magnesium salts, and ammonium salts.

15. A method for producing a composite material according to any one of claims 1 to 14, comprising the step of polymerizing a precursor solution comprising an inorganic gel precursor and a vaporizable material.

16. A method for producing a composite material in claim 15, wherein polymerization is performed while maintaining the pH of the precursor solution in a range of 3 to 14.

17. In the 15th or 16th paragraph, the polymerization is performed when the precursor solution has △T of the following formula 1 f A method for producing a composite material, which is performed at a temperature in the range of 10°C to 50°C, in a state in which an ionic compound is included so that the ratio of the ionic compound to the composite material is in the range of 1 to 50: [Formula 1] △T f = K f× M×I K in Equation 1 f is the freezing point depression constant of the volatile substance, M is the molal concentration of the ionic compound with respect to the volatile substance, and I is the number of moles of ions produced when 1 mole of the ionic compound is completely dissociated.

18. A method for producing a composite material according to any one of claims 15 to 17, wherein the polymerization comprises a step of stirring the precursor solution at a speed of 100 to 2,000 rpm.

19. A method for producing a composite material, comprising the step of polymerizing an inorganic gel precursor or a prepolymer of the precursor in the presence of inorganic fibers, according to any one of claims 15 to 18.

20. Case; and A heat absorbing device comprising a composite material according to any one of claims 1 to 15 present within the case.

21. In paragraph 20, an absorption device in which the absolute value of △T of the following equation 1 is 10% or less: [Formula 1] △T = 100 × (T2 - T1) / T1 In Equation 1, T1 is the thickness of the heat absorber at 25°C, and T2 is the thickness after the heat absorber is maintained at -30°C.

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