Fire spread prevention material, assembled battery, and automobile

Abstract

[Problem] To provide: a fire spread prevention material having sufficient fire spread prevention properties; an assembled battery using said fire spread prevention material; and an automobile comprising said assembled battery. [Solution] One aspect of the present invention provides a fire spread prevention material. The fire spread prevention material comprises: an inorganic fiber substrate containing inorganic fibers; and an inorganic substance supported on the inorganic fiber substrate and containing an inorganic acid salt. The moisture content of the inorganic substance at 30ºC is at most 60 mass%, and the activation energy of the moisture when 30% of the contained moisture is desorbed from the inorganic substance is at least 80 kJ / mol.

Description

Fire prevention materials, battery packs and automobiles

[0001] The present invention relates to a fire prevention material, a battery pack, and an automobile.

[0002] With the widespread adoption of electric vehicles, development of automotive battery packs and battery cells for use therein is progressing. Among automotive battery packs, batteries using lithium-ion battery (LiB) cells, which have high energy density, are particularly at risk of abnormalities such as thermal runaway. For this reason, development of technologies to improve the safety of battery cells is progressing. For example, Patent Document 1 proposes a heat-absorbing sheet used to prevent sudden temperature increases and thermal runaway (heat runaway) caused by internal short circuits in lithium-ion batteries. However, such heat-absorbing sheets do not necessarily have sufficient fire-spread prevention capabilities.

[0003] JP 2010-53196 A

[0004] In view of the above circumstances, the present invention provides a fire prevention material having sufficient fire spread prevention properties, a battery pack using this fire prevention material, and a vehicle equipped with this battery pack.

[0005] According to one aspect of the present invention, there is provided a fire spread prevention material. The fire spread prevention material includes an inorganic fiber substrate containing inorganic fibers, and an inorganic substance supported on the inorganic fiber substrate and containing an inorganic acid salt. The inorganic substance has a moisture content of 60 mass% or less at 30°C, and the moisture activation energy when 30% of the moisture content is desorbed from the inorganic substance is 80 kJ / mol or more.

[0006] According to this embodiment, sufficient fire spread prevention properties can be exhibited.

[0007] Fig. 1 is a schematic diagram showing the state of water molecules present in sodium silicate. Fig. 2 is a cross-sectional view schematically showing an embodiment of a fire spread prevention material. Fig. 3 is a cross-sectional view schematically showing an embodiment of a fire spread prevention material. Fig. 4(a) is a plan view schematically showing an embodiment of a fire spread prevention material including an exterior body. Fig. 4(b) is an enlarged view showing a side view and a cross-section of an end portion schematically showing an embodiment of a fire spread prevention material including an exterior body.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The various features described in the following embodiments can be combined with one another. In this specification, the content of Y in X refers to the proportion (mass %) of Y based on the total mass of X, and the moisture content of an inorganic substance refers to the proportion (mass %) of moisture based on the total mass of the inorganic substance. FIG. 1 is a schematic diagram showing the state of water molecules present in sodium silicate. FIGS. 2 and 3 are cross-sectional views each showing a schematic embodiment of a fire spread prevention material. The fire spread prevention material of this embodiment is used by being disposed between two adjacent battery cells of a battery pack having two or more battery cells. Here, the fire spread prevention material is required to have heat insulating properties (fire spread prevention properties) that suppress heat transfer to adjacent battery cells in the event of an abnormality.

[0009] First Embodiment The fire spread prevention material of the first embodiment includes an inorganic fiber substrate containing inorganic fibers and an inorganic substance supported on the inorganic fiber substrate and containing an inorganic acid salt. The moisture content of the inorganic substance at 30°C is approximately 60% by mass or less. That is, the inorganic substance contains an appropriate amount of moisture. Therefore, this fire spread prevention material retains moisture even when heated to temperatures of 100°C or higher. As a result, in an emergency, energy greater than or equal to the heat of vaporization of water is required to desorb the moisture, and the material exhibits excellent heat insulation properties (thermal insulation effect). Therefore, even if one battery cell were to catch fire in an emergency, the spread of fire to adjacent battery cells can be prevented or delayed.

[0010] The moisture content of the inorganic material at 30°C is preferably approximately 30% by mass or more and 60% by mass or less, and more preferably approximately 35% by mass or more and 55% by mass or less. In this case, the inorganic material contains a more moderate amount of moisture, which can sufficiently slow the temperature rise of the fire spread prevention material after it exceeds 100°C. This makes it easier to further improve the fire spread prevention effect of the fire spread prevention material in emergency situations. Furthermore, the fire spread prevention material can maintain high flexibility during production of the fire spread prevention material, storage of the fire spread prevention material, production of battery packs, etc. As a result, the productivity of the fire spread prevention material and battery packs can also be improved. Furthermore, if the moisture content of the inorganic material at 30°C is within the above range, the activation energy of moisture, as described below, also tends to be high.

[0011] The activation energy of water when 30% of the water contained in such an inorganic substance is desorbed is 80 kJ / mol or more. ２ O.nSiO ２ ・mH ２ Taking sodium silicate (a compound represented by the formula [m is 0 or a positive number]), the water molecules present in sodium silicate (an inorganic substance) are classified into I: free water, II: water molecules hydrogen-bonded with OH, III: water molecules adsorbed to Na (a constituent element), and IV: water molecules present as OH, as shown in Figure 1. The order of evaporation (desorption) of water molecules is thought to be I → II → III → IV (although evaporation may occur simultaneously).

[0012] Furthermore, the degree of desorption of water molecules from an inorganic substance is thought to be affected by structural changes of the inorganic substance, etc. Therefore, the present inventors have conducted extensive research into parameters that can comprehensively reflect these effects, and have found that the activation energy of water can simply represent the ease with which water (water molecules) desorb from an inorganic substance. This activation energy of water can be calculated, for example, from the results of thermogravimetry (TG).

[0013] Specifically, the activation energy Ea can be calculated from the slope of the following equation, which shows the relationship between the heating rate v in thermogravimetry and the reciprocal of the temperature T at which a specific moisture content reduction rate (mass reduction rate) Q is reached. In the following equation, R is the gas constant. Formula: Ln(v) = 0.4567Ea / RT + constant. The value of the moisture activation energy (80 kJ / mol or more) is much greater than the latent heat of moisture (44 kJ / mol). In other words, this value indicates that the water molecules are relatively firmly held by the inorganic material and are difficult to remove. In particular, in this embodiment, the value of the moisture activation energy is set to the value when 30% of the moisture content is removed from the inorganic material (i.e., when the moisture content reduction rate Q is 30%). Therefore, inorganic materials with such properties retain a sufficient amount of water molecules for a long period of time, thereby further enhancing the fire spread prevention effect of the fire prevention material in emergency situations.

[0014] The activation energy of the water is preferably about 120 kJ / mol or more, more preferably about 160 kJ / mol or more, even more preferably about 240 kJ / mol or more, and particularly preferably about 320 kJ / mol or more. In this case, the above effect can be further improved. On the other hand, the activation energy of the water is preferably about 800 kJ / mol or less, more preferably about 700 kJ / mol or less, even more preferably about 600 kJ / mol or less, and particularly preferably about 500 kJ / mol or less. This prevents water molecules from becoming extremely difficult to separate from the inorganic material. Therefore, the heat insulating properties (heat insulating effect) due to the separation of water is fully exhibited.

[0015] The moisture content of the inorganic material at 100°C is preferably approximately 15% by mass to 35% by mass, more preferably approximately 18% by mass to 32% by mass, and even more preferably approximately 21% by mass to 29% by mass. In this case, the inorganic material contains sufficient moisture even at 100°C, and in an emergency, the energy required for moisture desorption is greater than the latent heat of vaporization of free water (44 kJ / mol), so the insulating properties (insulating effect) are better exhibited. Therefore, even if one battery cell were to catch fire in an emergency, the spread of the fire to adjacent battery cells can be prevented or delayed. The moisture content of the inorganic material can be measured (determined) using the method described in the Examples.

[0016] The rate of decrease in moisture content of the inorganic material from 30°C to 100°C is preferably about 0.75% by mass / °C or less, more preferably about 0.65% by mass / °C or less, and even more preferably about 0.55% by mass / °C or less. In this case, the fire spread prevention material contains sufficient moisture in the temperature range of 30°C to 100°C, which can contribute to improving the productivity of the fire spread prevention material and the battery pack, and to stable operation of the battery pack. The rate of decrease in moisture content (mass% / °C) can be calculated using the following formula 1. Formula 1: Rate of decrease in moisture content (mass% / °C) = ([moisture content of inorganic material at 30°C] - [moisture content of inorganic material at 100°C]) / [moisture content of inorganic material at 30°C] x 100

[0017] The fire spread prevention properties of a fire spread prevention material can be evaluated by heating one side of the fire spread prevention material at 650°C for 30 seconds and measuring the surface temperature of the other side of the fire spread prevention material (surface temperature after 120 seconds). The surface temperature of the other side of the fire spread prevention material after 30 seconds is preferably about 180°C or less, more preferably about 150°C or less, and even more preferably about 120°C or less. The lower limit of the surface temperature is, for example, about 25°C. A fire spread prevention material that exhibits a surface temperature within the above range can be determined to have excellent fire spread prevention properties. The surface temperature can be measured using the method in the examples.

[0018] Furthermore, because the battery cells repeatedly expand and contract during charging and discharging of the battery pack, it is preferable that the fire spread prevention material have flexibility that can follow the expansion and contraction of the battery cells. In this case, by combining an inorganic fiber substrate carrying an inorganic substance with, for example, a polyurethane sheet material, the fire spread prevention material can be given good flexibility. This allows the fire spread prevention material to follow the expansion and contraction of the battery cells, reducing the mechanical load on the battery cells, thereby enabling the battery pack to repeatedly operate (charge and discharge) stably.

[0019] Examples of inorganic acid salts contained in the inorganic substance include silicates, aluminates, sulfates, hydrochlorides, nitrates, phosphates, borates, and hydrofluorides. Among these, the inorganic acid salt is preferably at least one selected from the group consisting of silicates, aluminates, and sulfates. These inorganic acid salts are suitable because they easily retain water molecules as crystal water, hydration water, etc., and easily cause foaming or porosity. The inorganic acid salt may be any type of salt, but is preferably at least one selected from the group consisting of alkali metal salts and alkaline earth metal salts, more preferably at least one selected from the group consisting of lithium salts, sodium salts, potassium salts, magnesium salts, and calcium salts, and even more preferably sodium salts and / or calcium salts. These elements are suitable because they easily adsorb water molecules.

[0020] It is preferable that the inorganic acid salt has crystal water, bound water (adsorbed water), etc. as water molecules. In this case, it is easy to prepare an inorganic substance having the above-mentioned properties. Considering the above, the inorganic acid salt is preferably sodium silicate, calcium sulfate, calcium silicate hydrate, CaO.Al ２ O ３ ・6H ２ O, CaO.Al ２ O ３ ・10H ２ O, 3CaO.Al ２ O ３ 3CaSO ４ ・32H ２ O (Etriganate), 3CaO.Al ２ O ３CaSO ４ ・12H ２ Preferably, calcium sulfate (monosulfate), cement hydrate, or a mixture containing these is used, and sodium silicate is more preferred. Note that an example of an inorganic substance containing calcium sulfate as a main component is gypsum.

[0021] As mentioned above, sodium silicate has water molecules in the state shown in Figure 1. Therefore, in the fire prevention material that becomes porous in the high temperature region, sodium silicate exhibits high heat insulating properties by containing water molecules in the above-mentioned states III and IV. Furthermore, from the viewpoint of increasing the moisture content in the high temperature region, Na contained in sodium silicate ２ Increasing the ratio of O (i.e., SiO ２ / Na ２ It is preferable to lower the SiO molar ratio. ２ / Na ２ The O molar ratio is preferably about 3.3 or less, more preferably about 2.7 or less, even more preferably about 1 to 2.5, and particularly preferably about 1.2 to 2.3.

[0022] In addition, the water molecules adsorbed on Na have a strong bond and are thought to be difficult to separate even at relatively high temperatures. ２ Increasing the proportion of O makes it easier to prevent a sudden temperature rise after the temperature of the fire prevention material exceeds 100°C. Therefore, even if one battery cell were to catch fire in an emergency, the spread of the fire to adjacent battery cells can be more reliably prevented or delayed. In addition, the use of such sodium silicate can further increase the productivity of the fire prevention material and battery packs.

[0023] In particular, the inorganic material preferably contains silicate and sulfate, and more preferably contains sodium silicate and calcium sulfate (i.e., gypsum). With this configuration, polyvalent ions (calcium ions) are introduced into the inorganic material, resulting in an increase in the amount of water molecules retained as crystal water, hydration water, etc. Furthermore, silicate (sodium silicate) undergoes structural changes (gelation, etc.) due to interaction with the polyvalent ions. For this reason, it is believed that the inorganic material's ability to retain water molecules is further enhanced, thereby more efficiently exerting the above-mentioned effects, and thus improving the fire spread prevention properties of the fire prevention material.

[0024] From this viewpoint, the sulfate is preferably a hydrate. In this case, it is easier to increase the water content of the inorganic substance. Examples of calcium sulfate hydrates include hemihydrate gypsum (CaSO ４ ・0.5H ２ O), gypsum dihydrate (CaSO ４ ・2H ２ O). The content of sulfate in the inorganic substance is preferably about 0.01% by mass or more and about 5% by mass or less, more preferably about 0.05% by mass or more and about 1% by mass or less, and even more preferably about 0.1% by mass or more and about 0.5% by mass or less. By using sulfate in such an amount in combination with silicate, depending on the type of silicate and the type of sulfate, it is easy to produce a fire prevention material that has better fire prevention properties than a fire prevention material that uses silicate alone.

[0025] The proportion of the inorganic material in the total inorganic material and inorganic fiber substrate is preferably about 60% by mass or more and about 98% by mass or less, more preferably about 70% by mass or more and about 95% by mass or less, and even more preferably about 75% by mass or more and about 90% by mass or less. In this case, it is easier to impart better fire spread prevention properties to the fire spread prevention material, and it is also possible to reduce the weight of the fire spread prevention material. The proportion of the inorganic fiber substrate in the total inorganic material and inorganic fiber substrate is preferably about 1% by mass or more and about 40% by mass or less, more preferably about 1% by mass or more and about 35% by mass or less, even more preferably about 5% by mass or more and about 35% by mass or less, particularly preferably about 8% by mass or more and about 30% by mass or less, and most preferably about 10% by mass or more and about 20% by mass or less. In this case, it is easier to impart better fire spread prevention properties to the fire spread prevention material.

[0026] The inorganic fiber substrate is a substrate (e.g., a sheet) composed primarily of inorganic fibers. Such an inorganic fiber substrate has a plurality of voids (pores) formed between the inorganic fibers. That is, the inorganic fiber substrate has a porous structure. For example, a relatively high-viscosity inorganic substance can be applied to one side of the inorganic fiber substrate and then dried to form a layer containing the inorganic substance unevenly distributed on one side of the inorganic fiber substrate. Furthermore, for example, a relatively low-viscosity inorganic substance (e.g., an aqueous solution, a slurry, etc.) can be prepared, impregnated into the inorganic fiber substrate, and then dried to fill the inorganic substance into the voids of the inorganic fiber substrate.

[0027] In this specification, inorganic fibers are fibrous substances having a length of about 1 mm or more and an aspect ratio (length / width) of about 100 or more. The length (fiber length) of the inorganic fibers is preferably about 3 mm or more and 12 mm or less. The width (fiber diameter) of the inorganic fibers is preferably about 3 μm or more and 10 μm or less. When the inorganic fibers constituting the inorganic fiber substrate have the above fiber length and fiber diameter, the inorganic fiber substrate tends to have excellent shape processability before drying in the manufacturing process. From the same viewpoint, the average fiber diameter of the inorganic fibers is preferably about 5 μm or more and 10 μm or less. Here, the average fiber diameter is a value measured by microscope observation such as a scanning electron microscope (SEM) or an optical microscope.

[0028] The inorganic fiber constituting the inorganic fiber substrate may be of one type or of multiple types. Examples of the constituent material of the inorganic fiber constituting the inorganic fiber substrate include silica (SiO ２ ), alumina (Al ２ O ３ ), carbon, silicon carbide (SiC), etc. Among these, the constituent material of the inorganic fiber is silica (SiO ２ ) and alumina (Al ２ O ３ ) It is preferable that the inorganic fiber substrate contains at least one selected from the group consisting of. In this case, higher fire spread prevention properties can be imparted to the fire spread prevention material, and in the manufacturing process of the inorganic fiber substrate, it tends to have excellent shape processability before drying. Examples of such inorganic fibers include glass fiber, silica fiber, alumina-silica fiber, alumina fiber, basalt fiber, rock wool, etc. Among these, it is preferable that the inorganic fiber substrate contains at least one of glass fiber, silica fiber, and alumina-silica fiber. In this case, the above-mentioned effects can be further improved.

[0029] The content of inorganic fibers in the inorganic fiber substrate is preferably approximately 60% by mass or more and 100% by mass or less, more preferably approximately 70% by mass or more and 98% by mass or less, even more preferably approximately 80% by mass or more and 95% by mass or less, and particularly preferably approximately 85% by mass or more and 93% by mass or less. In this case, the fire spread prevention material can impart excellent fire spread prevention properties. The inorganic fiber substrate may further contain an organic binder. The organic binder is, for example, an organic material that bonds the inorganic fibers together, and one type may be used alone or multiple types may be used in combination. As the organic binder, for example, a resin having a glass transition point below room temperature (e.g., 25°C) or a water-soluble resin may be used. Specific examples of organic binders include, for example, acrylic resins, polyvinyl alcohol resins (such as vinylon), epoxy resins, cellulose such as cellulose microfibrils, polyvinyl chloride resins, etc.

[0030] Here, the acrylic resin is a polymer containing at least one monomer unit selected from the group consisting of acrylic acid and its derivatives (such as acrylic acid esters), and methacrylic acid and its derivatives (such as methacrylic acid esters). Furthermore, cellulose microfibrils refer to microfibrillated cellulose fibers. In particular, the organic binder preferably contains at least one selected from the group consisting of acrylic resins, polyvinyl alcohol resins, and epoxy resins. In this case, a fire-spread prevention material with higher fire-spread prevention properties tends to be obtained. The content of the organic binder in the inorganic fiber substrate is preferably about 0% by mass or more and about 40% by mass or less, more preferably about 2% by mass or more and about 30% by mass or less, even more preferably about 5% by mass or more and about 20% by mass or less, and particularly preferably about 7% by mass or more and about 15% by mass or less. In this case, a fire-spread prevention material with better fire-spread prevention properties is more easily obtained.

[0031] The inorganic fiber substrate may further contain inorganic particles. Examples of constituent materials of the inorganic particles include silica, aluminum hydroxide, zinc oxide, magnesium carbonate, and aluminum silicate. Examples of silica-containing particles include precipitated silica, fumed silica, and colloidal silica. Precipitated silica is an amorphous silica particle obtained by a precipitation method, which is a type of wet method, and has a porous structure. The average particle size of the inorganic particles is preferably about 0.01 μm to about 100 μm, more preferably about 0.1 μm to about 80 μm, even more preferably about 0.5 μm to about 80 μm, and particularly preferably about 1 μm to about 50 μm. Here, the average particle size of the inorganic particles is the volume cumulative particle size D50 value measured using a laser diffraction particle size analyzer. Inorganic particles having such an average particle size are easy to handle and can be more uniformly distributed in the inorganic fiber substrate.

[0032] The content of inorganic particles in the inorganic fiber substrate is preferably about 20% by mass or more and about 50% by mass or less, more preferably about 25% by mass or more and about 45% by mass or less, and even more preferably about 30% by mass or more and about 40% by mass or less. By containing inorganic particles at such a content, heat insulation properties are improved and a fire spread prevention material with better fire spread prevention properties is obtained. In addition, an inorganic fiber substrate (and thus a fire spread prevention material) that is lighter and has higher mechanical strength can be obtained. Note that, from the viewpoint of increasing the mechanical strength of the inorganic fiber substrate, it is preferable that the inorganic fiber substrate does not contain precipitated silica, and more preferably does not contain inorganic particles.

[0033] The inorganic fiber substrate may contain a flocculant such as a polyamidine polymer. The content of the flocculant in the inorganic fiber substrate is preferably about 0.1% by mass or more and about 5% by mass or less, more preferably about 0.3% by mass or more and about 4% by mass or less, and even more preferably about 0.5% by mass or more and about 3% by mass or less. The inorganic fiber substrate may contain sodium silicate, or it may not contain such sodium silicate. When such sodium silicate is contained, the content of sodium silicate in the inorganic fiber substrate is preferably about 10% by mass or less, more preferably about 5% by mass or less, and even more preferably about 3% by mass or less.

[0034] As the inorganic fiber substrate, for example, it is preferable to use a substrate that has excellent inorganic substance retention (carrying ability). The inorganic fiber substrate is preferably a nonwoven fabric, and more preferably a sheet (wet-formed sheet) formed by a wet papermaking method. The wet-formed sheet is preferable from the viewpoint of being particularly excellent in sodium silicate retention. In the wet papermaking method, an inorganic fiber substrate (nonwoven fabric) is produced by dispersing materials (inorganic fibers, organic binders, etc.) in water, forming the obtained dispersion on a papermaking screen, and drying it. According to this method, an inorganic fiber substrate (nonwoven fabric) having substantially uniformly dispersed voids can be easily obtained. Therefore, wet-formed sheets tend to have substantially uniformly dispersed voids and have excellent inorganic substance retention. The apparent density of the inorganic fiber substrate is 0.08 g / cm ３ 0.2g / cm or more ３The weight per unit area of ​​the inorganic fiber substrate is preferably about 100 g / m when the thickness is 1 mm. ２ Below 170g / m ２ The thickness of the inorganic fiber substrate is preferably 0.2 mm or more and 3 mm or less.

[0035] The inorganic substance may be unevenly distributed on one side of the inorganic fiber substrate, or may be impregnated into the inorganic fiber substrate. That is, the fire spread prevention material 1 may have a two-layer structure of an inorganic fiber substrate 2 and a layer 3 containing the inorganic substance IM, as shown in FIG. 2, or a single-layer structure in which the inorganic fiber substrate 2 is impregnated with the inorganic substance IM, as shown in FIG. 3. The two-layer fire spread prevention material 1 can be formed, for example, by applying a relatively high-viscosity inorganic substance IM to one side of the inorganic fiber substrate 2 and then drying the applied material, thereby unevenly distributing the layer 3 containing the inorganic substance IM on one side of the inorganic fiber substrate 2. Suitable methods for this application include gravure coating, slot die coating, knife coating, blade coating, comma coating, reverse roll coating, and inkjet coating.

[0036] On the other hand, a single-layer fire prevention material 1 can be produced, for example, by impregnating an inorganic fiber substrate 2 with a relatively low viscosity inorganic material IM, pressurizing it as necessary, and then drying it, thereby filling the voids in the inorganic fiber substrate 2 with the inorganic material IM.

[0037] In the configuration example of Figure 2, layer 3, and in the configuration example of Figure 3, fire spread prevention material 1 (hereinafter referred to as the "inorganic substance-containing portion") preferably absorb heat in the temperature range of 100°C or higher and 300°C or lower. Furthermore, when the inorganic substance-containing portion is heated from 100°C to 300°C at 10°C / min, the mass loss rate is preferably 15% by mass or higher. The heat absorption of the inorganic substance-containing portion is thought to occur when moisture in the inorganic substance-containing portion (e.g., water molecules in the inorganic substance) undergoes an endothermic reaction in the temperature range of 100°C or higher and 300°C or lower. On the other hand, the mass loss of the inorganic substance-containing portion is thought to occur due to this endothermic reaction.

[0038] Therefore, the mass loss rate when the inorganic-containing portion is heated from 100°C to 300°C at 10°C / min correlates with the amount of moisture contained in the inorganic-containing portion and the amount of heat absorbed. For this reason, it is presumed that when the mass loss rate of the inorganic-containing portion is 15% by mass or more, the amount of heat absorbed in the above temperature range is large, and sufficient fire spread prevention properties can be obtained in the fire spread prevention material. The heat absorption of the inorganic-containing portion can be confirmed, for example, by performing thermogravimetry-differential thermal analysis (TG-DTA) measurement and checking the presence or absence of an endothermic peak in the temperature range of 100°C to 300°C.

[0039] When the inorganic substance-containing portion is heated from 100°C to 300°C at 10°C / min, the mass loss rate is preferably about 15% by mass to 30% by mass, more preferably about 17% by mass to 28% by mass, even more preferably about 20% by mass to 25% by mass, particularly preferably about 23% by mass to 25% by mass, and most preferably about 23.5% by mass to 25% by mass. In this case, a fire spread prevention material with better fire spread prevention properties is easily obtained. The mass loss rate can be calculated using the following formula 2. Formula 2: Mass loss rate (mass%) = [mass loss of inorganic substance-containing portion] / [mass of inorganic substance-containing portion at 100°C] x 100 Here, the mass loss of the inorganic substance-containing portion is the difference between the mass of the inorganic substance-containing portion at 100°C and the mass of the inorganic substance-containing portion at 300°C. When a plurality of inorganic substance-containing portions are present, the mass loss rate of each inorganic substance-containing portion may be within the above range, or the total mass loss rate of all the inorganic substance-containing portions may be within the above range.

[0040] The fire spread prevention material preferably has insulating properties. In this case, for example, by protecting both sides of the inorganic fiber substrate carrying the inorganic substance with a resin sheet material or by housing the inorganic fiber substrate carrying the inorganic substance in an exterior body 5 described later, the fire spread prevention material can be given high insulating properties. Here, having insulating properties means that the electrical resistivity measured by volume resistivity measurement is 1×10 ８This means that the resistance is Ω·cm or more. The fire spread prevention material may be in the form of a sheet (e.g., a flat plate) or may be processed into a predetermined shape. The predetermined shape may be appropriately set according to the shape of the installation location of the fire spread prevention material. The predetermined shape may be, for example, a shape that follows the shape of the installation location of the fire spread prevention material (such as the surface shape of the component placed opposite the fire spread prevention material). Specific examples of shapes include a sheet shape with an uneven surface, a sheet shape with a curved portion at an angle of 90° or more, etc. The shape of the unevenness (the shape of the convex and concave portions) is not particularly limited and may be a rectangular cross section, a V-shaped cross section, a U-shaped cross section, etc. The fire spread prevention material processed into a predetermined shape can be manufactured by the manufacturing method described below, thereby preventing separation and breakage between the inorganic fiber substrate and the inorganic material. The absence of separation and breakage in the fire spread prevention material can be confirmed, for example, by observing the cross section of the fire spread prevention material using a scanning electron microscope (SEM).

[0041] Once processed into a predetermined shape, the fire spread prevention material can maintain that shape. The ability of the fire spread prevention material to maintain its predetermined shape can be quantified by its three-point bending strength. Specifically, the three-point bending strength of the fire spread prevention material measured according to JIS K 7171 is preferably approximately 0.5 MPa to 5 MPa, more preferably approximately 0.8 MPa to 4 MPa, and even more preferably approximately 1 MPa to 3 MPa. A fire spread prevention material with such three-point bending strength can be said to have sufficient strength to maintain its predetermined shape. The total thickness of the inorganic fiber substrate and the inorganic material (the thickness of one sheet of fire spread prevention material 1 in the configuration examples of Figures 2 and 3) is preferably approximately 5 mm or less, preferably approximately 0.5 mm to 5 mm, more preferably approximately 1 mm to 4 mm, and even more preferably approximately 1.5 mm to 3 mm. In this case, a fire spread prevention material with higher fire spread prevention properties can be obtained, and the installation space for the fire spread prevention material within the battery pack can be prevented from becoming too large. In addition, the fire spread prevention material 1 may be used by stacking multiple sheets.

[0042] As shown in Fig. 4, the fire spread prevention material 1 may further include an exterior body 5 that houses the inorganic fiber substrate 2 and the inorganic material IM. In other words, the fire spread prevention material 1 can be said to include a fire spread prevention material main body, which is the inorganic fiber substrate 2 carrying the inorganic material IM, and an exterior body 5 that houses this fire spread prevention material main body. By housing the inorganic material IM within the exterior body 5, the amount of moisture dissipated from the fire spread prevention material 1 can be adjusted (reduced). Fig. 4(a) is a plan view that schematically shows an embodiment of a fire spread prevention material that includes an exterior body. Fig. 4(b) is an enlarged view showing a side view and a cross section of an end that schematically shows an embodiment of a fire spread prevention material that includes an exterior body. The water vapor transmission rate of the exterior body 5 at 40°C and 90% RH is 15 g / m ２ / day or less, and ２ / day or less is more preferable, and ２ / day or less, and ２ It is particularly preferable that the lower limit of the water vapor transmission rate of the exterior body 5 at 40°C is about 0.01 g / m ２ By setting the water vapor transmission rate of the exterior body 5 within the above range, the amount of moisture dissipated from the fire spread prevention material 1 can be more reliably adjusted (reduced), thereby further improving fire spread prevention. The water vapor transmission rate (water vapor permeability) is measured by a method in accordance with JIS K 7129-2:2019.

[0043] The outer peripheries of two sheet materials 5a, 5b are sealed with a seal portion 50, and the composite of the inorganic fiber substrate 2 and the inorganic material IM is contained inside the outer peripheries of the two sheet materials 5a, 5b. The seal portion 50 is formed by joining the outer peripheries of the two sheet materials 5a, 5b by a method such as fusion (ultrasonic fusion, high-frequency fusion, or heat fusion). Alternatively, one sheet material may be folded in half and its periphery sealed with a seal portion to contain the composite of the inorganic fiber substrate 2 and the inorganic material IM inside. In this embodiment, each sheet material 5a, 5b is a laminate including a base layer 51, a seal layer 52 provided on the inner side of the base layer 51, and a protective layer 53 provided on the outer side of the base layer 51.

[0044] The substrate layer 51 has functions such as imparting mechanical strength to the sheet materials 5a and 5b and regulating (blocking) moisture (water vapor) permeation. The substrate layer 51 may be made of a metal foil. Examples of materials for this metal foil include aluminum or an aluminum alloy, nickel or a nickel alloy, and stainless steel. The thickness of the substrate layer 51 is not particularly limited, but is preferably approximately 5 μm to 100 μm, more preferably approximately 8 μm to 80 μm, and even more preferably approximately 12 μm to 60 μm. In this case, the sheet materials 5a and 5b can have adequate water vapor permeability and sufficient flexibility.

[0045] The sealing layer 52 functions to seal the exterior body 5 by being fused. Examples of materials (fusible materials) that can be used for the sealing layer 52 include polyethylene (LDPE, LLPDE), polypropylene, ethylene-vinyl acetate copolymer, polyethylene terephthalate, polybutylene terephthalate, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl alcohol copolymer, polystyrene, polyacrylonitrile, ethylene-(meth)acrylic acid copolymer, and polymethylpentene. Polypropylene is a more preferred material for the sealing layer 52, and unstretched polypropylene is even more preferred. The thickness of the sealing layer 52 is not particularly limited, but is preferably approximately 5 μm to 200 μm, more preferably approximately 10 μm to 100 μm, even more preferably approximately 20 μm to 120 μm, and particularly preferably approximately 30 μm to 80 μm. This allows for improved sealing while maintaining the flexibility of the sheet materials 5a and 5b.

[0046] The protective layer 53 has a function of protecting the base layer 51 (preventing corrosion of the base layer 51, etc.). A relatively hard resin material is used as the constituent material of the protective layer 53. Examples of such hard resin materials include polyamide resins (nylon), acrylic resins, polyimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, polycarbonate resins, polyvinyl butyral resins, polyarylate resins, fluorine-containing resins, and polyester resins. The thickness of the protective layer 53 is not particularly limited, but is preferably about 5 μm to 100 μm, more preferably about 10 μm to 50 μm, and even more preferably about 15 μm to 30 μm.

[0047] The thickness of the exterior body 5 is not particularly limited, but is preferably approximately 250 μm or less, more preferably approximately 200 μm or less, and even more preferably approximately 100 μm or less. In this case, it becomes easier to set the water vapor permeability of the exterior body 5 within the above range. As a result, the amount of moisture dissipated from the fire spread prevention material 1 can be suitably adjusted (reduced), thereby further improving fire spread prevention. Note that the sheet materials 5a and 5b are not limited to a three-layer structure, and may be a single-layer (one-layer) structure, a two-layer structure, or a four-layer or more structure depending on the required characteristics. The fire spread prevention material according to the first embodiment has been described above, but the fire spread prevention material of the present invention is not limited to the first embodiment.

[0048] Second Embodiment The fire spread prevention material of the second embodiment will be described below, focusing on the differences from the fire spread prevention material of the first embodiment, and similar points will not be described again. The fire spread prevention material of the second embodiment includes an inorganic fiber substrate containing inorganic fibers and an inorganic material supported on the inorganic fiber substrate. The inorganic material includes a silicate and an inorganic calcium salt other than silicate. In the second embodiment, the moisture content of the inorganic material at 30°C is preferably 60% by mass or less, but does not necessarily have to be 60% by mass or less.

[0049] Examples of silicates include sodium silicate, potassium silicate, calcium silicate, etc., which can be used alone or in combination of two or more, with sodium silicate being preferred. Examples of inorganic calcium salts include calcium sulfate, calcium carbonate, calcium phosphate, calcium aluminate, calcium chloride, calcium hydroxide, etc., which can be used alone or in combination of two or more, with calcium sulfate (i.e., gypsum) being preferred.

[0050] By using such inorganic calcium salts, polyvalent ions (calcium ions) are introduced into the inorganic material, resulting in an increase in the amount of water molecules retained in the inorganic material as crystal water, hydration water, etc. Furthermore, silicate (sodium silicate) undergoes structural changes (gelation, etc.) due to interaction with the polyvalent ions. As a result, the inorganic material's ability to retain water molecules is enhanced, and the above-mentioned effects are more efficiently exerted, which is thought to improve the fire spread prevention properties of the fire prevention material.

[0051] From this viewpoint, the inorganic calcium salt is preferably a hydrate. In this case, it is easier to increase the water content of the inorganic material. Examples of calcium sulfate hydrates include hemihydrate gypsum (CaSO ４ ・0.5H ２ O), gypsum dihydrate (CaSO ４ ・2H ２ O). The content of the inorganic calcium salt in the inorganic substance is preferably about 0.01% by mass or more and about 0.5% by mass or less, more preferably about 0.02% by mass or more and about 0.3% by mass or less, and even more preferably about 0.03% by mass or more and about 0.1% by mass or less. By using an inorganic calcium salt in such an amount in combination, depending on the type of silicate and the type of inorganic calcium salt, it is easy to produce a fire spread prevention material that has better fire spread prevention properties than a fire spread prevention material that uses a silicate alone.

[0052] Another embodiment of the present invention provides a battery pack including two or more battery cells and the above-described fire spread prevention material disposed between adjacent battery cells. This battery pack is, for example, a lithium-ion battery. Another embodiment of the present invention provides a vehicle including a vehicle body and the above-described battery pack mounted in the vehicle body. The present invention may further be provided in the following aspects.

[0053] (1) A fire spread prevention material comprising an inorganic fiber substrate containing inorganic fibers and an inorganic substance supported on the inorganic fiber substrate and containing an inorganic acid salt, wherein the water content of the inorganic substance at 30°C is 60 mass% or less, and the activation energy of water when 30% of the water content is desorbed from the inorganic substance is 80 kJ / mol or more.

[0054] (2) The fire prevention material according to (1) above, wherein the activation energy of the moisture is 800 kJ / mol or less.

[0055] (3) The fire prevention material according to (1) or (2) above, wherein the inorganic acid salt is at least one selected from the group consisting of silicates, aluminates, and sulfates.

[0056] (4) In the fire prevention material described in any one of (1) to (3) above, the inorganic acid salt is at least one selected from the group consisting of alkali metal salts and alkaline earth metal salts.

[0057] (5) A fire prevention material according to any one of (1) to (4) above, wherein the inorganic acid salt has water molecules.

[0058] (6) In the fire prevention material according to any one of (1) to (5), the inorganic acid salt is SiO ２ / Na ２ A fire prevention material which is sodium silicate having an O molar ratio of 3.3 or less.

[0059] (7) In the fire prevention material according to any one of (1) to (6) above, the constituent material of the inorganic fiber is silica (SiO ２ ) and alumina (Al ２ O ３) A fire prevention material comprising at least one selected from the group consisting of:

[0060] (8) The fire prevention material according to any one of (1) to (7) above, wherein the inorganic fiber substrate is a wet-formed sheet.

[0061] (9) In the fire prevention material described in any one of (1) to (8) above, the inorganic substance is unevenly distributed on one side of the inorganic fiber substrate or is impregnated into the inorganic fiber substrate.

[0062] (10) The fire spread prevention material according to any one of (1) to (9) above, wherein the total thickness of the inorganic fiber substrate and the inorganic material is 5 mm or less.

[0063] (11) The fire spread prevention material according to any one of (1) to (10) above, further comprising an exterior body that houses the inorganic fiber base material and the inorganic material.

[0064] (12) In the fire spread prevention material described in (11) above, the exterior body has a water vapor permeability of 15 g / m at 40°C and 90% RH. ２ / day or less and a thickness of 250 μm or less.

[0065] (13) A battery pack comprising two or more battery cells and a fire prevention material according to any one of (1) to (12) above, disposed between adjacent battery cells.

[0066] (14) A vehicle comprising a vehicle body and the battery pack according to (13) above, mounted in the vehicle body.

[0067] (15) A fire spread prevention material comprising an inorganic fiber substrate containing inorganic fibers and an inorganic substance supported on the inorganic fiber substrate, wherein the inorganic substance contains silicate and an inorganic calcium salt other than silicate, and the content of the inorganic calcium salt in the inorganic substance is 0.01% by mass or more and 1% by mass or less.

[0068] (16) The fire prevention material according to (15) above, wherein the silicate is sodium silicate.

[0069] (17) The fire prevention material according to (15) or (16) above, wherein the inorganic calcium salt is calcium sulfate.

[0070] (18) The fire prevention material according to any one of (15) to (17) above, wherein the inorganic calcium salt is a hydrate. Of course, this is not a limitation.

[0071] Finally, while various embodiments of the present disclosure have been described, they are presented as examples and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. Such embodiments and modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as defined in the claims.

[0072] The present invention will be described in more detail below using the following examples and comparative examples, but the present invention is not limited to the following examples.

[0073] 1. Preparation of materials <Inorganic substances (inorganic acid salts)> IM1: Sodium silicate (SiO ２ / Na ２ O molar ratio = 2.1, water content at 30 ° C: 37.0 mass%) IM2: sodium silicate (SiO ２ / Na ２ O molar ratio = 3.2, water content at 30 ° C: 45.0 mass%)

[0074] IM3: Ordinary Portland cement (water content at 30°C: 22.0% by mass) 0.5Gyp: Hemihydrate gypsum (CaSO ４ ・0.5H ２ O) 2Gyp: Gypsum dihydrate (CaSO ４ ・2H ２ O)

[0075] <Inorganic fiber> F1: Glass fiber (average fiber diameter 10 μm) <Organic binder> B1: Vinylon fiber (average fiber diameter 5 μm)

[0076] 2. Preparation of inorganic fiber substrate (wet-formed sheet) 6.5 parts by mass of inorganic fiber F1 and 0.7 parts by mass of organic binder B1 were added to 100 parts by mass of pure water and mixed for 2 hours using a homomixer manufactured by Tokushu Kika Kogyo Co., Ltd. to obtain a dispersion. This dispersion was formed into a papermaking screen and dried using a Yankee dryer to produce a wet-formed sheet (nonwoven fabric). The thickness of the wet-formed sheet was 0.6 mm and the basis weight was 120 g / m. ２ It was.

[0077] 3. Preparation of fire spread prevention material (Sample No. 1) The inorganic substance IM1 was impregnated into a wet-formed sheet (inorganic fiber substrate), compressed with a roller, and then dried at 100°C for 10 minutes. This produced a fire spread prevention material with a single layer structure in which the inorganic substance IM1 was filled into the voids of the wet-formed sheet. The thickness of the obtained fire spread prevention material was 0.6 mm.

[0078] (Sample No. 2) A single-layer fire prevention material was prepared in the same manner as Sample No. 1, except that inorganic material IM1 was replaced with inorganic material IM2. The thickness of the resulting fire prevention material was 0.6 mm. (Sample No. 3) Inorganic material IM3 was applied to a wet-laid sheet (inorganic fiber substrate) and then allowed to stand at 25°C for 3 days. This resulted in a two-layer fire prevention material in which inorganic material IM3 was applied to the surface of the wet-laid sheet. The thickness of the resulting fire prevention material was 1.3 mm. (Sample No. 4) Water was impregnated into a wet-laid sheet (inorganic fiber substrate). This was used as a fire prevention material. The thickness of the resulting fire prevention material was 0.6 mm.

[0079] 4. Measurement and Evaluation 4-1. Measurement of Moisture Content For each of the inorganic materials IM1 to IM3, the mass change up to 1000°C was measured using a thermogravimetric analyzer (a high-sensitivity differential thermobalance, STA 2500 Regulus, manufactured by NETZSCH Japan). The measured value at 1000°C was defined as the "amount of solids contained in each of the inorganic materials IM1 to IM3," and the moisture content at 30°C for each of the inorganic materials IM1 to IM3 was calculated from this value of the solids amount and the measured value from the thermogravimetric measurement.

[0080] 4-2. Measurement of Moisture Activation Energy For each of the inorganic materials IM1 to IM3, thermogravimetric measurements were performed using the same thermogravimetric measuring device as described above at heating rates of 5°C / min, 10°C / min, 20°C / min, 30°C / min, and 50°C / min. At each heating rate, the temperature [°C] at which the moisture content loss rate reached 40% (40% of the moisture content was desorbed) was measured. The moisture activation energy Ea was then calculated based on the formula [Ln(v) = 0.4567Ea / RT + constant]. Table 1 below shows the results measured for inorganic material IM1. Table 2 shows the results measured for inorganic materials IM2 to IM3.

[0081]

[0082] 4-3. Confirmation of endothermic peak First, a portion of the obtained fire spread prevention material was collected and pulverized to obtain a measurement sample. Next, a thermogravimetric-differential thermal analyzer (TG-DTA) was used to perform DTA measurement on the measurement sample, and a differential thermal curve was obtained when the temperature was raised from room temperature to 300°C at a rate of 10°C / min. In the obtained differential thermal curve, it was confirmed whether or not an endothermic peak was present in the temperature range from 100°C to 300°C.

[0083] 4-4. Evaluation of Fire Spread Prevention One or two fire spread prevention materials, one aluminum thin plate (thickness: 0.5 mm), a K thermocouple, two glass fiber sheets (thickness per sheet: 0.6 mm), and an aluminum block (500 g) were layered in this order on a hot plate ("PA8015" manufactured by MSA Factory) heated to 650°C. The back surface temperature of the fire spread prevention material (the surface temperature on the side opposite the hot plate) was measured after 30 seconds, and the fire spread prevention property was evaluated according to the following criteria.

[0084] A: The back surface temperature of the fire spread prevention material was 180°C or less. B: The back surface temperature of the fire spread prevention material was higher than 180°C and 220°C or less. C: The back surface temperature of the fire spread prevention material was higher than 220°C. In addition, when the fire spread prevention material was rated as "B" according to the above criteria, the fire spread prevention material was evaluated as having sufficient fire spread prevention properties, and when the fire spread prevention material was rated as "A", the fire spread prevention material was evaluated as having excellent fire spread prevention properties. These results are shown in Table 2 below.

[0085]

[0086] Each of the fire prevention materials of Samples No. 1 to 4 was placed between two exterior sheets (manufactured by Toppan Printing Co., Ltd., "GX-PF", thickness 200 μm, water vapor permeability 0.05 g / m ２ The outer periphery is sealed to produce an exterior body. This produces the same results as above. Furthermore, the effect tends to be greater than that of the corresponding examples. Furthermore, similar results can be obtained by using silica fiber, alumina fiber, or alumina-silica fiber instead of glass fiber. Furthermore, similar results can be obtained by producing a two-layer fire prevention material using the inorganic materials IM1 to IM3.

[0087] 5. Preparation of Fire Prevention Material (Sample No. 11) First, inorganic material 0.5 Gyp was dispersed in a small amount of water, and then inorganic material IM2 was mixed with this dispersion using a rotation / revolution mixer (Thinky Corporation, "Awatori Rentaro") at a rotation speed of 2000 rpm for 90 seconds. This mixture was then compressed with a roller into a 0.7 mm thick glass fiber (Olivest Co., Ltd., "SB-100TS") and dried at 100 ° C. so that the moisture content of the entire inorganic material at 30 ° C. was 35% by mass. This produced a single-layer fire prevention material in which the mixture was filled into the voids of a wet-laid sheet. The content of 0.5 Gyp in the entire inorganic material was 20% by mass.

[0088] (Sample No. 12) A fire prevention material with a single layer structure was prepared in the same manner as Sample No. 11, except that the content of 0.5 Gyp in the entire inorganic material was set to 5 mass%. (Sample No. 13) A fire prevention material with a single layer structure was prepared in the same manner as Sample No. 11, except that the content of 0.5 Gyp in the entire inorganic material was set to 1 mass%. (Sample No. 14) A fire prevention material with a single layer structure was prepared in the same manner as Sample No. 11, except that the content of 0.5 Gyp in the entire inorganic material was set to 0.5 mass%.

[0089] (Sample No. 15) A fire prevention material with a single layer structure was prepared in the same manner as Sample No. 11, except that the content of 0.5 Gyp in the entire inorganic material was set to 0.1 mass%. (Sample No. 16) A fire prevention material with a single layer structure was prepared in the same manner as Sample No. 11, except that the content of 0.5 Gyp in the entire inorganic material was set to 0 mass%.

[0090] (Sample No. 21) A single-layer fire prevention material was prepared in the same manner as Sample No. 11, except that 0.5 Gyp was changed to 2 Gyp. (Sample No. 22) A single-layer fire prevention material was prepared in the same manner as Sample No. 12, except that 0.5 Gyp was changed to 2 Gyp. (Sample No. 23) A single-layer fire prevention material was prepared in the same manner as Sample No. 13, except that 0.5 Gyp was changed to 2 Gyp.

[0091] (Sample No. 24) A single-layer fire prevention material was prepared in the same manner as Sample No. 14, except that 0.5 Gyp was changed to 2 Gyp. (Sample No. 25) A single-layer fire prevention material was prepared in the same manner as Sample No. 15, except that 0.5 Gyp was changed to 2 Gyp. (Sample No. 26) A single-layer fire prevention material was prepared in the same manner as Sample No. 16, except that 0.5 Gyp was changed to 2 Gyp.

[0092] 6. Evaluation of Fire Spread Prevention One fire spread prevention material, one aluminum thin plate (thickness: 0.5 mm), a K thermocouple, two glass fiber sheets (thickness per sheet: 0.6 mm), and an aluminum block (500 g) were layered in this order on a hot plate ("PA8015" manufactured by MSA Factory) heated to 650°C. The time required to reach 200°C was then measured. The results are shown in Table 3 below.

[0093] As shown in Table 3, it was confirmed that by using gypsum in combination with sodium silicate in a range of 0.01 mass % or more and 1 mass % or less in total inorganic matter, the time required to reach 200°C can be extended in the evaluation of fire spread prevention properties.

[0094] 1: Fire prevention material, 2: Inorganic fiber substrate, 3: Layer, 5: Exterior body, 5a: Sheet material, 5b: Sheet material, 50: Sealing portion, 51: Base material layer, 52: Sealing layer, 53: Protective layer, IM: Inorganic material

Claims

1. A fire spread prevention material comprising: an inorganic fiber substrate containing inorganic fibers; and an inorganic substance supported on the inorganic fiber substrate and containing an inorganic acid salt, wherein the moisture content of the inorganic substance at 30°C is 60 mass% or less, and the activation energy of moisture when 30% of the moisture content is desorbed from the inorganic substance is 80 kJ / mol or more.

2. A fire prevention material according to claim 1, wherein the activation energy of the moisture is 800 kJ / mol or less.

3. A fire prevention material according to claim 1 or 2, wherein the inorganic acid salt is at least one selected from the group consisting of silicates, aluminates and sulfates.

4. A fire prevention material according to any one of claims 1 to 3, wherein the inorganic acid salt is at least one selected from the group consisting of alkali metal salts and alkaline earth metal salts.

5. A fire prevention material according to any one of claims 1 to 4, wherein the inorganic acid salt has water molecules.

6. In the fire prevention material according to any one of claims 1 to 5, the inorganic acid salt is SiO ２ / Na ２ A fire prevention material which is sodium silicate having an O molar ratio of 3.3 or less.

7. In the fire prevention material according to any one of claims 1 to 6, the constituent material of the inorganic fibers is silica (SiO ２ ) and alumina (Al ２ O ３ ) A fire prevention material comprising at least one selected from the group consisting of:

8. A fire prevention material according to any one of claims 1 to 7, wherein the inorganic fiber substrate is a wet-formed sheet.

9. A fire spread prevention material according to any one of claims 1 to 8, wherein the inorganic substance is unevenly distributed on one side of the inorganic fiber substrate or is impregnated into the inorganic fiber substrate.

10. A fire prevention material according to any one of claims 1 to 9, wherein the total thickness of the inorganic fiber substrate and the inorganic material is 5 mm or less.

11. A fire prevention material according to any one of claims 1 to 10, further comprising an exterior body that houses the inorganic fiber base material and the inorganic substance.

12. The fire prevention material according to claim 11, wherein the exterior body has a water vapor permeability of 15 g / m at 40°C and 90% RH. ２ / day or less and a thickness of 250 μm or less.

13. An assembled battery comprising: two or more battery cells; and a fire prevention material according to any one of claims 1 to 12, disposed between adjacent battery cells.

14. A vehicle comprising: a vehicle body; and the battery pack according to claim 13 mounted in the vehicle body.

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