Inorganic fiber blankets, laminates, battery pack units and electric mobility

Abstract

A flame-retardant inorganic fiber blanket, a battery pack cover using this inorganic fiber blanket, a battery pack unit using this battery pack cover, and an electric mobility device using this battery pack unit are provided. [Solution] Basis weight 700g / m 2 The following, and bulk density 0.125 g / cm³ 3 An inorganic fiber blanket consisting of the needle blanket described above. A battery pack cover having this inorganic fiber blanket. A battery pack unit using this battery pack cover. An electric mobility device using this battery pack unit.

Description

[Technical Field]

[0001] This invention relates to inorganic fiber blankets, laminates, battery pack units, and electric mobility. [Background technology]

[0002] A battery pack unit used in electric mobility devices such as electric vehicles (EVs) comprises a housing and a battery pack disposed within the housing (Patent Document 1: WO2019 / 044801).

[0003] Patent Document 1 describes a container being constructed from a laminate in which a non-combustible or flame-retardant fiber layer, such as glass fiber, is provided on one side of a synthetic resin plate. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] WO2019 / 044801 [Overview of the project] [Problems that the invention aims to solve]

[0005] In EV battery packs, the energy density of battery modules installed in electric vehicles tends to increase in order to extend driving range, and the demands on battery heat generation and the risk of thermal runaway are increasing. If a battery catches fire due to thermal runaway, a fire-resistant material with excellent flame-blocking properties is required in the gap between the battery pack and the battery pack cover to delay the spread of fire to interior materials. However, the gap between the battery pack and the battery pack cover is limited, so the fire-resistant material must be thin. If it is too thick, there is a risk that either the battery pack or the battery pack cover will be crushed. On the other hand, if the thickness of the fire-resistant material is made too thin, it will not be able to exhibit sufficient flame-blocking performance.

[0006] An object of the present invention is to provide an inorganic fiber blanket having excellent flame shielding properties. Further, the present invention aims to provide a laminate using this inorganic fiber blanket, a battery pack unit having this inorganic fiber blanket, and an electric mobility using this battery pack unit.

Means for Solving the Problems

[0007] The present inventors have found that an inorganic fiber blanket with a high bulk density can be obtained by devising the needle process, and further have found that an inorganic fiber blanket having a specific bulk density and basis weight can achieve both thickness and flame shielding performance. The gist of the present invention is as follows.

[0008] [1] An inorganic fiber blanket characterized by including a needle blanket having a basis weight of 700 g / m , , , ,

[0011] or more and a bulk density of 0.125 g / cm 3 or more.

[0009] [2] The inorganic fiber blanket according to [1], wherein the needle blanket has needle penetration marks penetrating from one surface to the other surface, and the needle penetration mark density is 35 pieces / cm 2 or less.

[0010] [3] An inorganic fiber blanket having a basis weight of 700 g / m 2 or less and a bulk density of 0.125 g / cm 3 or more, wherein a laminate composed of the inorganic fiber blanket and an aluminum alloy plate with a thickness of 0.8 mm is used as a test piece, and it is not penetrated in a flame test at a flame temperature of 1000 °C and an air ejection speed of 〖100 m / s〗 for 5 minutes.

[0011] [4] The inorganic fiber blanket according to any one of [1] to [3], having a peel strength of 4.0 N or more specified by the following method. <Measurement Method of Peel Strength> Measure using a tensile testing machine. The effective part size of the test piece shall be 50 mm × 75 mm. Make a cut 25mm along the length of one end of the 50mm wide side, in the center of the thickness. The ends formed by the cuts are grasped and attached to a tensile testing machine, and pulled at a speed of 100 mm / min. The maximum value of the load is defined as the peel strength.

[0012] A laminate characterized by having an inorganic fiber blanket and a base material as described in any of [5] [1] to [4].

[0013] [6] The laminate according to [5], wherein the substrate is a metal substrate.

[0014] [7] The laminate according to [6], wherein the metal is aluminum, an aluminum alloy, magnesium, a magnesium alloy, titanium, a titanium alloy, iron, or stainless steel.

[0015] [8] A laminate according to any of [5] to [7], used as a battery pack cover.

[0016] [9] A battery pack unit having an inorganic fiber blanket as described in any of [1] to [4].

[0017] A battery pack unit having a laminate described in

[10] [8] and a battery pack, A battery pack unit in which the inorganic fiber blanket of the laminate is positioned on the battery pack side.

[0018] A battery pack unit having a laminate described in

[11] [8] and a battery pack, A battery pack unit in which the substrate of the laminate is positioned closer to the battery pack than the inorganic fiber blanket.

[0019]

[12] An electric mobility device equipped with one of the battery pack units from [9] to

[11] . [Effects of the Invention]

[0020] The inorganic fiber blanket used in the present invention has a small basis weight and a high bulk density, so even if the thickness is small, it has excellent heat shielding properties. Therefore, the battery cover provided with this inorganic fiber blanket has excellent heat shielding properties.

Brief Description of the Drawings

[0021] [Figure 1] FIG. 1 shows a mode in which the battery pack cover 5 covers the entire surface of the battery pack 3. [Figure 2] FIG. 2 shows a mode in which the battery pack cover 5 is disposed only on a part of the upper surface of the battery pack 3. [Figure 3] Explanatory drawing of the peel strength test. [Figure 4] Schematic diagram of the test piece used in the peel strength test. [Figure 5] Explanatory drawing of the needling treatment.

Modes for Carrying Out the Invention

[0025] The bulk density of the inorganic fiber blanket is 0.125 g / cm³. 3 Preferably 0.130 g / cm³ 3 That concludes the explanation. There is no upper limit to the bulk density, but it is preferably 0.200 g / cm³. 3 The following is particularly preferred: 0.150 g / cm³ 3 The following applies:

[0026] Bulk density is 0.125 g / cm³ 3 If the above conditions are met, the amount of fiber per unit volume is sufficient, thus providing flame-retardant properties and wind pressure resistance against explosions caused by thermal runaway of the battery pack.

[0027] The thickness of the inorganic fiber blanket (a value measured by the method described in the examples below) is preferably 0.1 mm or more, more preferably 1.0 mm or more, and particularly preferably 2.0 mm or more. Furthermore, the thickness of the inorganic fiber blanket is preferably 5.0 mm or less, more preferably 4.0 mm or less, and particularly preferably 3.0 mm or less.

[0028] The basis weight and thickness of the inorganic fiber blanket can be set to the above range by adjusting the amount of fiber per unit area when stacking the inorganic fiber aggregates constituting the inorganic fiber blanket using a folding device.

[0029] The inorganic fibers constituting this inorganic fiber blanket are not particularly limited and include silica, alumina / silica, zirconia containing these, spinel, titania, and other single or composite fibers. The inorganic fibers are preferably alumina / silica-based fibers, and particularly preferably crystalline alumina / silica-based fibers. The composition ratio (mass ratio) of alumina / silica in the alumina / silica-based fibers is preferably in the range of 60-95 / 40-5, more preferably in the range of 70-84 / 30-16, and particularly preferably in the range of 70-76 / 30-24.

[0030] Furthermore, the inorganic fibers are preferably fibers with an average fiber length of 1.0 mm or more, more preferably 2.0 mm or more, and even more preferably 3.0 mm or more. Also, the average fiber length is preferably 3.0 × 10 3 mm or less, more preferably 1.0 × 10 3 The fibers are less than 1 mm in diameter. The average fiber diameter of the inorganic fibers is preferably 3 to 10 μm, and particularly preferably 5 to 8 μm. It is preferable that the inorganic fiber blanket has high tensile strength when the average fiber length and average fiber diameter of the inorganic fibers are within this range. It is also preferable that the amount of dust generated that floats in the air is suppressed when the average fiber length and average fiber diameter of the inorganic fibers are within this range. The average fiber length of the inorganic fibers is the average value of 300 fibers measured by microscopic observation. The average fiber diameter is the average value of 100 fibers measured by microscopic observation.

[0031] The inorganic fiber blanket of the present invention can be obtained by various methods, for example, by papermaking or needling.

[0032] The inorganic fiber blanket is preferably a needle blanket that has undergone a needling treatment. By applying the needling treatment, needle penetration marks are formed in the inorganic fiber blanket that penetrate from one surface to the other. The surface of the inorganic fiber blanket perpendicular to the thickness direction may hereafter be referred to as the mat surface. Also, the side surface (the surface in the thickness direction) of the inorganic fiber blanket perpendicular to the mat surface may be referred to as the end surface. That is, the inorganic fiber blanket in the first invention of this invention has a basis weight of 700 g / m². 2 The following, and bulk density 0.125 g / cm³ 3 This is an inorganic fiber blanket that includes the needle blanket described above.

[0033] <Needle penetration mark density> When visible light is shone on the matte surface of an inorganic fiber blanket, the amount of transmitted light at needle penetration marks is greater than the amount of transmitted light in areas other than the needle penetration marks, so the transmitted light is observed as light spots on the delamination surface. The number of needle penetration marks can be determined by counting the number of light spots due to transmission to the delamination surface.

[0034] Also, the unit area (1cm²) of the mat surface of the inorganic fiber blanket. 2 The number of needle penetration marks per square centimeter (needle penetration mark density) is preferably 35 marks / cm² as an average value across the entire mat surface. 2 More preferably, 32 pieces / cm 2 The following is preferable: If the number of needle penetration marks is within the above range, it is possible to provide wind pressure resistance against explosion due to thermal runaway of the battery pack, and it is also preferable to be able to control the thickness range so that it can be inserted between the battery pack and the substrate.

[0035] In this invention, the unit area (1 cm²) of the mat surface of the inorganic fiber blanket 2 The number of needle penetration marks per square centimeter (needle penetration mark density) is preferably 5 marks / cm² as an average value across the entire mat surface. 2 More than 6 pieces / cm 2That concludes the explanation. If the number of needle penetration marks is kept within the above range, the interlayer peel strength and tensile strength of the entire mat can be improved in terms of the amount of fiber restraint by the warp threads, thereby improving the flame-retardant performance.

[0036] The inorganic fiber blanket in the second invention of this invention has a basis weight of 700 g / m². 2 The following, and bulk density 0.125 g / cm³ 3 The inorganic fiber blanket described above is one that, in a flame test with a flame temperature of 1000°C and an air ejection velocity of 100 m / s, does not penetrate the laminate for 5 minutes.

[0037] <Peel strength> The inorganic fiber blanket of the present invention preferably has a peel strength of 4.0 N or higher, more preferably 5.0 N or higher, and particularly preferably 6.0 N or higher, as determined by the load peak (N) in the peel test described below. A higher peel strength of the inorganic fiber blanket is advantageous.

[0038] A peel strength of 4.0N or higher is preferable because it provides wind pressure resistance against explosion due to thermal runaway of the battery pack. Furthermore, when bonded to the battery pack cover substrate using an adhesive, peeling is less likely to occur in the surface layer, and the adhesion can be maintained without falling off the substrate during driving.

[0039] <Peel test> A 50mm x 75mm test specimen is cut out from an inorganic fiber blanket. As shown in Figures 3 and 4, a 25mm deep cut is made in the center of the thickness of one end face in the longitudinal direction of this test specimen 11. The ends formed by the cut are then grasped and supported by a jig 12, and the specimen is set on a tensile testing machine. It is then pulled at a speed of 100mm / min in opposing directions perpendicular to the mat surface, and the maximum value of the load is defined as the peel strength.

[0040] <Tensile strength> The inorganic fiber blanket has a tensile strength of preferably 20 N or more, preferably 25 N or more, and particularly preferably 30 N or more. A higher tensile strength is preferable for the inorganic fiber blanket, and there is no upper limit, but it is preferably 100 kN or less, and particularly preferably 50 kN or less. The tensile strength is the value measured by the method described in the examples below.

[0041] [Method for manufacturing inorganic fiber blankets] Inorganic fiber blankets can be obtained by various methods, for example, by papermaking or needling. In the case of papermaking, inorganic fibers are opened, the opened inorganic fibers are dispersed in a solvent, the solvent in the resulting mixture is desolvated, and the mixture is dried to produce a papermaking mat. In the case of needling, for example, it can be produced by the following method.

[0042] [Method for manufacturing needle blankets] Needle blankets can be manufactured by a method comprising the steps of obtaining a mat-like aggregate of inorganic fiber precursors by a sol-gel method, subjecting the obtained mat-like aggregate (assembly) of inorganic fiber precursors to a needling treatment, and firing the needling-treated mat-like aggregate of inorganic fiber precursors to form an inorganic fiber blanket. However, needle blankets may be manufactured by other methods.

[0043] The following describes an example of a method for manufacturing a needling-treated inorganic fiber blanket, using the method for manufacturing an alumina / silica-based fiber blanket as an example. However, the inorganic fiber blanket of the present invention is not limited to an alumina / silica-based fiber blanket, and as mentioned above, it may be a blanket made of silica, zirconia, spinel, titania, or composite fibers thereof.

[0044] <Spinning Process> To produce a mat-like aggregate of alumina / silica fibers by the sol-gel method, first, a spinning solution containing basic aluminum chloride, a silicon compound, an organic polymer as a thickener, and water is spun by the blowing method to obtain an aggregate of alumina / silica fiber precursors.

[0045] <<Preparation of spinning solution>> Basic aluminum chloride; Al(OH) 3-x Cl x This can be prepared, for example, by dissolving metallic aluminum in hydrochloric acid or an aqueous solution of aluminum chloride. The value of x in the above chemical formula is usually 0.45 to 0.54, preferably 0.5 to 0.53. Silica sol is preferably used as the silicon compound, but other water-soluble silicon compounds such as tetraethyl silicate and water-soluble siloxane derivatives can also be used. Water-soluble polymer compounds such as polyvinyl alcohol, polyethylene glycol, and polyacrylamide are preferably used as organic polymers. The degree of polymerization of these is usually 1000 to 3000.

[0046] The spinning solution preferably has a ratio of aluminum derived from basic aluminum chloride to silicon derived from silicon compounds, which is typically 99:1 to 65:35, preferably 99:1 to 70:30, when converted to a mass ratio of Al2O3 to SiO2, with an aluminum concentration of 150 to 210 g / L and an organic polymer concentration of 15 to 50 g / L.

[0047] If the amount of silicon compounds in the spinning solution is less than the above range, the alumina constituting the short fibers is more likely to become α-alumina, and the short fibers are more likely to become brittle due to the coarsening of the alumina particles. On the other hand, if the amount of silicon compounds in the spinning solution is more than the above range, the amount of silica (SiO2) produced together with mullite (3Al2O3·2SiO2) increases, and the heat resistance tends to decrease.

[0048] If the aluminum concentration in the spinning solution is less than 150 g / L or the organic polymer concentration is less than 15 g / L, in either case, an appropriate viscosity of the spinning solution cannot be obtained, and the fiber diameter of the resulting alumina / silica-based fibers will be small. In other words, as a result of too much free water in the spinning solution, the drying rate during spinning by the blowing method is slow, the stretching proceeds excessively, the fiber diameter of the spun precursor fibers changes, and short fibers with a predetermined average fiber diameter and a sharp fiber diameter distribution cannot be obtained. Moreover, if the aluminum concentration is less than 150 g / L, productivity decreases. On the other hand, if the aluminum concentration exceeds 210 g / L or the organic polymer concentration exceeds 50 g / L, in either case, the viscosity is too high to become a spinning solution. The preferred concentration of aluminum in the spinning solution is 160-200 g / L, and the preferred concentration of organic polymer is 20-40 g / L.

[0049] The above spinning solution is prepared by adding an amount of silicon compound and an organic polymer in the above Al2O3:SiO2 ratio to an aqueous solution of basic aluminum chloride, and concentrating it so that the concentrations of aluminum and organic polymer fall within the above range.

[0050] ≪Blowing≫ Spinning (fibrillation of the spinning solution) is usually carried out by a blowing method, in which the spinning solution is supplied into a high-speed spinning airflow, thereby obtaining an alumina short fiber precursor. There are no particular restrictions on the structure of the spinning nozzle used in the above spinning process, but a structure in which the airflow blown out from the air nozzle and the spinning solution flow pushed out from the spinning solution supply nozzle are parallel flows, and moreover, the parallel flow of air is sufficiently rectified to come into contact with the spinning solution, is preferred, for example, as described in Japanese Patent Publication No. 2602460.

[0051] Furthermore, during spinning, it is preferable that, first, sufficiently stretched fibers are formed from the spinning solution under conditions where the evaporation of moisture and the decomposition of the spinning solution are suppressed, and then these fibers are dried quickly. To achieve this, it is preferable to change the atmosphere from a state that suppresses the evaporation of moisture to a state that promotes the evaporation of moisture during the process from when the fibers are formed from the spinning solution until they reach the fiber collector.

[0052] Alumina / silica fiber precursors can be collected and accumulated using an accumulation device that has a structure in which an endless wire mesh belt is set up approximately perpendicular to the spinning airflow, and the spinning airflow containing the alumina / silica fiber precursors is made to collide with the endless belt while it is rotating, thereby recovering them as a continuous sheet-like accumulation (thin layer sheet) of alumina / silica fiber precursors.

[0053] The basis weight of this thin sheet is preferably 10 to 300 g / m². 2 Particularly preferred is 30-200 g / m². 2 This is the extent of it, but it is not limited to this.

[0054] The thin sheets recovered from the above-mentioned accumulation device can be further laminated. Specifically, for example, an aggregate of inorganic fiber precursors (thin sheets) can be continuously drawn out and sent to a folding device, where they can be folded to a predetermined width and stacked while being continuously moved in a direction perpendicular to the folding direction to form a laminated aggregate of inorganic fiber precursors (laminated sheet). By laminating the thin sheets in this way, the basis weight (weight) of the laminated sheet becomes uniform throughout the entire sheet. As the above-mentioned folding device, the one described in Japanese Patent Application Publication No. 2000-80547 can be used.

[0055] <Needling aid or friction reducer application process> Needling aids or anti-friction agents are applied to the sheet surface of a thin sheet or laminated sheet of alumina / silica-based inorganic fiber precursor obtained by spinning, as needed. It is preferable to apply the needling aid or anti-friction agent to both sheet surfaces.

[0056] As a needling aid, any agent that has the effect of strengthening the filaments near the mat surface of the inorganic fiber precursor aggregate can be used, and various coating agents, such as acrylic polymer coating agents, can be used.

[0057] As a friction reducer, surfactants or emulsions that reduce friction between the needle and the fiber can be used. Needling aids and friction reducers are applied by coating (wet coating) the solution or dispersion.

[0058] <Needling process> After applying a needling aid and / or anti-friction agent as needed to a laminated sheet of alumina / silica-based inorganic fiber precursor obtained by spinning, a needling process is performed by inserting and removing a needle 7 having a barb 8 into the laminated sheet 9, as shown in Figure 5. The needling process may be performed from only one side of the laminated sheet or from both sides. Preferably, it is performed from both sides.

[0059] As shown in Figure 5, it is preferable that the needle 7 is inserted and removed perpendicular to the sheet surface of the laminated sheet 9. It is preferable that the needle is inserted so as to penetrate the laminated sheet in the thickness direction.

[0060] In this way, needle penetration marks are formed in the inorganic fiber blanket by the needling process. That is, when a needling process is performed in which a barbed needle is inserted and removed from a laminated sheet, at least some of the fibers are extended in the approximate thickness direction by the needle at the points where the needle has been inserted and removed. As a result, needle penetration marks are formed on the surface of the inorganic fiber blanket. Within the inorganic fiber blanket that has been treated with the needling process, the threads of inorganic fibers that extend in the approximate thickness direction are called warp threads.

[0061] Needling is performed to adjust the bulk density and peel strength of the inorganic fiber blanket by forming warp threads.

[0062] <Firing Process> The inorganic fiber blanket is preferably a sintered body obtained by sintering a needling-treated inorganic fiber precursor. Sintering is usually carried out at a temperature of 900°C or higher, preferably 1000 to 1300°C. A sintering temperature of 900°C or higher is preferable because sufficient crystallization is achieved, resulting in alumina / silica-based fibers with excellent strength. A sintering temperature of 1300°C or lower is also preferable because excessive grain growth of the fiber crystals is not achieved, resulting in alumina / silica-based fibers with moderate strength.

[0063] The laminate of the present invention comprises an inorganic fiber blanket and a base material. The inorganic fiber blanket and the base material may be simply stacked on top of each other, or they may be bonded together with an adhesive or the like. The laminate of the present invention is preferably used as a battery pack cover that covers a battery pack.

[0064] [Base material] The substrate to which the inorganic fiber blanket is laminated is not limited, and housing materials such as metal substrates and reinforced resin substrates can be used. From the viewpoint of flame resistance, metal substrates are preferred, and aluminum, aluminum alloys, magnesium, magnesium alloys, titanium, titanium alloys, iron, stainless steel, etc. are suitable. If the laminate of the present invention has excellent flame resistance, it is suitable and preferred for use as a battery pack cover.

[0065] [Battery Pack Unit] The battery pack unit of the present invention comprises a battery pack and a battery pack cover having an inorganic fiber blanket.

[0066] Figures 1 and 2 are schematic cross-sectional views showing examples of battery pack units.

[0067] This battery pack unit 1 comprises a base material (sometimes called a battery pack cover base material when used as a battery pack cover) 2, a battery pack 3 placed inside the base material 2, and an inorganic fiber blanket 4 placed between the battery pack 3 and the base material 2. The inorganic fiber blanket 4 and the base material 2 are overlapped to form a battery pack cover 5. They may be bonded together with an adhesive. The inorganic fiber blanket 4 is placed inside the battery pack unit 1 relative to the base material 2, but may also be placed outside the base material 2. The battery pack 3 comprises a plurality of battery modules 6 or a plurality of individual battery cells 6. The inorganic fiber blanket 4 may be placed to cover the entire surface of the pack 3, or it may be placed on a part of it. If it is placed on a part, the location is not limited and may be the top, bottom, side, or a combination of these locations.

[0068] Figure 1 shows a configuration in which the battery pack cover 5 covers the entire surface of the battery pack 3. Figure 2 shows a configuration in which the battery pack cover 5 is positioned only on the upper surface of a portion of the battery pack 3. In this configuration, it is positioned over the vent portion (air outlet) of the battery module 6 or individual battery cell 6. Also, in Figure 2, the battery pack cover base material 2 and the portion S for housing the battery pack are separated.

[0069] This battery pack unit 1 can improve the flame resistance of the battery pack cover without compromising loadability, and is therefore suitable for use in batteries for electric mobility devices such as electric vehicles, electric motorcycles, and ships. The battery is not limited to any particular type and can include, for example, lithium-ion batteries, nickel-metal hydride batteries, lithium-sulfur batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, sodium-sulfur batteries, lead-acid batteries, air batteries, and solid-state batteries. Among these, lithium-ion batteries are preferred.

[0070] Examples [Example 1] <Manufacturing of inorganic fiber blankets> To an aqueous solution of basic aluminum chloride (aluminum content 165 g / L, Al / Cl = 1.8 (atomic ratio)), silica sol was added so that the final alumina fiber composition would be Al2O3:SiO2 = 72:28 (mass ratio). After adding polyvinyl alcohol, the solution was concentrated to prepare a spinning solution with a viscosity of 70 poise (25°C) and an alumina-silica content of approximately 35% by mass.

[0071] The above spinning solution was spun using the blowing method. As the spinning nozzle, a spinning nozzle with the same structure as that described in Figure 6 of Japanese Patent Publication No. 2602460 was used. Furthermore, for cotton collection, an endless belt made of wire mesh was set approximately perpendicular to the spinning airflow, and the cotton was collected as a continuous sheet (thin sheet) using an accumulation device with a structure that caused the spinning airflow containing alumina / silica-based fiber precursors to collide with the endless belt while it was rotating.

[0072] The thin sheets recovered from the accumulation device were coated with an anti-friction agent by spray, then continuously drawn out and sent to a folding device. There, they were folded to a predetermined width and stacked, while being continuously moved in a direction perpendicular to the folding direction to form laminated sheets. The folding device used was one with a structure similar to that described in Japanese Patent Publication No. 2000-80547.

[0073] The basis weight can be changed by varying the number of times the fiber precursor is folded using the stacking device.

[0074] The mat-like aggregate of alumina / silica fiber precursors obtained by spinning was subjected to needling treatment using needles 7, as shown in Figure 5. Needling was performed by punching using a needle punching machine. Needling was performed from both sides. When needling the laminated sheet 9 of inorganic fiber precursors, the needle was inserted so that it penetrated from one side to the other, and the needling was performed so that a predetermined needle penetration mark density was achieved after firing, and an average of 5 barbs 8 per needle penetrated the other side.

[0075] Afterward, it is fired at 1200°C, resulting in a basis weight of 600g / m². 2 (Thickness 4.0 mm, bulk density 0.15 g / cm³) 3 ), needle penetration mark density: 30.2 marks / cm 2 An inorganic fiber blanket 1 consisting of crystalline alumina / silica fibers was obtained. Sintering was performed in an electric furnace, heating to 1200°C at a rate of 5°C / min, holding at 1200°C for 30 minutes, and then allowing to cool naturally.

[0076] The composition ratio of this crystalline alumina / silica fiber was alumina / silica = 72 / 28 (by mass), and the average fiber diameter (average of 100 fibers) of the crystalline alumina / silica fiber, measured by microscopic observation of the inorganic fiber blanket, was 5.5 μm.

[0077] [Example 2] The needle penetration mark density was 13.7 marks / cm². 2 Needling and firing are performed to achieve a basis weight of 600g / m². 2 Thickness 4.3mm, bulk density 0.140g / cm³ 3 An inorganic fiber blanket made of crystalline alumina / silica-based fibers was obtained in the same manner as in Example 1, except that the result was as follows.

[0078] [Example 3] The needle penetration mark density was 40.3 marks / cm². 2 Needling and firing are performed to achieve a basis weight of 600g / m². 2 Thickness 4.1 mm, bulk density 0.146 g / cm³ 3 An inorganic fiber blanket made of crystalline alumina / silica-based fibers was obtained in the same manner as in Example 1, except that the result was as follows.

[0079] [Example 4] In the needling process of Example 1, the needling and firing process was carried out so that an average of 4 barbs penetrated the other surface, resulting in a basis weight of 600 g / m². 2 Thickness 4.0 mm, bulk density 0.150 g / cm³ 3An inorganic fiber blanket made of crystalline alumina / silica-based fibers was obtained in the same manner as in Example 1, except that the result was as follows.

[0080] [Example 5] The needle penetration mark density was 30.2 marks / cm². 2 , basis weight 700g / m² 2 To achieve this, the number of layers was changed, and the material was subjected to needling and firing, resulting in a thickness of 4.5 mm and a bulk density of 0.156 g / cm³. 3 An inorganic fiber blanket made of crystalline alumina / silica-based fibers was obtained in the same manner as in Example 1, except that the result was as follows.

[0081] [Example 6] The needle penetration mark density is 30.2 marks / cm². 2 , basis weight 500g / m² 2 To achieve this, the number of layers was changed, and the material was subjected to needling and firing, resulting in a thickness of 3.7 mm and a bulk density of 0.135 g / cm³. 3 An inorganic fiber blanket made of crystalline alumina / silica-based fibers was obtained in the same manner as in Example 1, except that the result was as follows.

[0082] [Comparative Example 1] In the needle-piercing process of Example 1, the needles were inserted such that, compared to Example 1, the number of barbs penetrating to the other surface was an average of 1 per needle, and the needle penetration mark density was 6.8 marks / cm². 2 Needling and firing are performed to achieve a basis weight of 600g / m². 2 Thickness 5.3mm, bulk density 0.113g / cm³ 3 An inorganic fiber blanket made of crystalline alumina / silica-based fibers was obtained in the same manner as in Example 1, except that the result was as follows.

[0083] <<Measurement of physical properties of inorganic fiber blankets>> For each inorganic fiber blanket obtained in the above examples and comparative examples, the peel strength and needle penetration mark density were measured using the method described above, and the tensile strength, thickness, and flame test were performed as follows. The results are shown in Table 1.

[0084] • Method for measuring peel strength The measurement was performed using a tensile testing machine. The effective size of the test specimen was 50 × 75 mm. A cut was made in the center of the thickness of one end on the 50 mm wide side, extending 25 mm in the longitudinal direction. The ends formed by the cut were grasped and attached to the tensile testing machine, and the specimen was pulled at a speed of 100 mm / min. The maximum value of the load was defined as the peel strength.

[0085] • Tensile strength measurement test method The tensile strength was measured using a tensile testing machine. The size of the parallel section (effective section) of the test specimen was 25 mm x 100 mm, and the overall size was 25 mm x 160 mm. Each inorganic fiber blanket in its product state was cut to the above size using a die, mounted on a tensile testing machine, and pulled at a speed of 25 mm / min. The maximum value of the load was defined as the tensile strength.

[0086] • Method for measuring thickness The measurement was performed using a digital dial gauge. The measured load was 4.9 kPa (50 g / cm²). 2 The minimum measurement scale is 0.01 mm. The test piece cut out using the method described later in the flame test method was randomly measured at 5 points using the measuring jig, and the average of the 5 points was used as the representative measurement value.

[0087] • Flame testing method The inorganic fiber blankets of Examples 1-6 and Comparative Example 1 were punched out in a die to a length of 3600 mm. 2 It was cut to the following size. The cut inorganic fiber blanket was placed on each aluminum alloy plate (3600mm 2 A test specimen was prepared by stacking two pieces (with a thickness of 0.8 mm) and then conducting the following flame test.

[0088] The test specimen was clamped and fixed in a stainless steel jig, and positioned 70 mm away from the tip of the torch burner. The test specimen was positioned so that the inorganic fiber blanket side faced the burner, and the mat surface of the inorganic fiber blanket was approximately perpendicular to the burner axis.

[0089] A flame was supplied to this torch burner (Sakaguchi Seisakusho: WT-01, nozzle diameter 1.2 mm) for 30 minutes at O2 0.50 MPa, C2H 20.02 MPa, and an air pressure of 0.24 MPa from an air nozzle (discharge port diameter 3.0 mm, positioned 40 mm away from the test piece, with the mat surface of the inorganic fiber blanket approximately perpendicular to the air nozzle axis). A flame at a temperature of 1000°C and air at a velocity of 100 m / s were sprayed towards the test piece for 10 seconds every 2 minutes, up to a maximum of 15 times.

[0090] After 30 minutes and 30 seconds had elapsed since the flame was first directed at the inorganic fiber blanket of the test specimen, the specimen was removed, and it was visually inspected to see if penetration had occurred in the inorganic fiber blanket. If penetration occurred due to air (or flame) during the test, the specimen was removed at the point of penetration, and the number of air injections required until penetration was defined as the number of flame test endurance cycles.

[0091] [Table 1]

[0092] <Consideration> As shown in Table 1, the inorganic fiber blanket of the present invention exhibits excellent flame resistance and can withstand a large number of flame tests, even with its thin thickness.

[0093] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention.

[0094] This application is based on Japanese Patent Application No. 2021-188751, filed on 19 November 2021, which is incorporated herein by reference in its entirety.

[0095] 1 Battery Pack Unit 2. Base material (battery pack cover base material) 3 Battery Packs 4. Inorganic fiber blanket 5. Battery pack cover 5' Battery Pack Cover 6 Battery Modules 7 Needles 8 barbs 9 Laminated Sheets 11. Test specimens of inorganic fiber blankets 12 Gripping jig

Claims

1. Basis weight 700g / m ２ The following, and bulk density 0.125 g / cm³ ３ The needle blanket includes the above-described needle blanket, which has needle penetration marks that penetrate from one surface to the other surface, and has a needle penetration mark density of 35 marks / cm². ２ An inorganic fiber blanket characterized by the following:

2. The inorganic fiber blanket according to claim 1, characterized in that it does not penetrate for 5 minutes in a flame test using a laminate consisting of the inorganic fiber blanket and an aluminum alloy plate with a thickness of 0.8 mm as the test specimen, with a flame temperature of 1000°C and an air ejection velocity of 100 m / s.

3. The inorganic fiber blanket according to claim 1 or 2, wherein the peel strength, as determined by the following method, is 4.0 N or greater. <Method for measuring peel strength> The measurement is performed using a tensile testing machine. The effective area of ​​the test specimen shall be 50 x 75 mm. Make a cut 25 mm along the length of one end of the 50 mm wide side, in the center of the thickness. The ends formed by the cuts are grasped and attached to a tensile testing machine, and pulled at a speed of 100 mm / min. The maximum value of the load is defined as the peel strength.

4. A laminate comprising an inorganic fiber blanket and a substrate as described in claim 1 or 2.

5. The laminate according to claim 4, wherein the substrate is a metal substrate.

6. The laminate according to claim 5, wherein the metal is aluminum, aluminum alloy, magnesium, magnesium alloy, titanium, titanium alloy, iron, or stainless steel.

7. The laminate according to claim 4, used as a battery pack cover.

8. A battery pack unit having an inorganic fiber blanket according to claim 1 or 2.

9. A battery pack unit comprising a laminate according to claim 7 and a battery pack, wherein the inorganic fiber blanket of the laminate is disposed on the battery pack side.

10. A battery pack unit comprising a laminate according to claim 7 and a battery pack, wherein the base material of the laminate is positioned on the battery pack side of the inorganic fiber blanket.

11. An electric mobility device comprising the battery pack unit of claim 8.

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