Battery protection sheet and battery pack module

Abstract

The present application provides a battery protection sheet and a battery module having high thermal insulation in addition to mechanical impact resistance. The battery protection sheet (1) has a papermaking sheet layer (10) containing first inorganic fibers and a cloth layer (20) composed of second inorganic fibers. In addition, the battery module has a plurality of battery packs, a housing that houses the battery packs, and the battery protection sheet attached to the inner side of the housing.

Description

Technical Field

[0001] This invention relates to a protective sheet for batteries and a battery pack module. Background Technology

[0002] In recent years, rechargeable batteries using non-aqueous electrolytes have been widely used in automotive power supplies, portable communication devices, laptops, and other applications. These batteries feature high energy density and the ability to insert active metals into active materials, resulting in high safety.

[0003] Such secondary batteries offer high safety under normal use, but various accidents are contingent upon the possibility of short circuits caused by metal objects such as nails penetrating from the outside. Furthermore, secondary batteries utilize organic electrolytes, and in recent years, the stacking of multiple battery cells to increase capacity has led to an increase in the amount of organic electrolyte, making it crucial to ensure safety.

[0004] In Patent Document 1, in order to improve safety, a secondary battery made of impact-resistant materials such as aramid fiber, glass fiber, UHMWPE fiber and polybenzoxazole fiber is described.

[0005] Existing technical documents

[0006] Patent Document 1: Japanese Patent Publication No. 2013-545235 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] The invention described above is designed to prevent damage to the secondary battery itself. However, if damage occurs and heat is generated, the heat will be transferred to the outside of the heated secondary battery, damaging the casing covering the secondary battery. The organic electrolyte of the secondary battery will react with the outside air, thereby further promoting heat generation.

[0009] In view of the aforementioned technical problems, the present invention aims to provide a battery protection sheet and battery pack module that, in addition to mechanical impact resistance, also has high thermal insulation properties.

[0010] Means for solving technical problems

[0011] Regarding the battery protection sheet of the present invention used to solve the aforementioned technical problem...

[0012] Structure (1) has a paper sheet containing a first inorganic fiber and a fabric layer composed of a second inorganic fiber.

[0013] The battery protective sheet of the present invention comprises a paper-formed sheet layer containing a first inorganic fiber and a fabric layer composed of a second inorganic fiber. Therefore, the paper-formed sheet layer has high thermal insulation, and the fabric layer has mechanical impact resistance, thus possessing both thermal insulation and impact resistance. That is, the first inorganic fiber is short in length, like chopped or ground fiber, in order to facilitate papermaking, thereby blocking heat transfer, and the second inorganic fiber is a continuous fiber in order to form the fabric, utilizing its long fiber length to ensure high strength.

[0014] Structure (2): The average fiber length of the first inorganic fiber is 0.5 to 10 mm.

[0015] The first inorganic fiber has an average fiber length of 0.5 mm or more. Therefore, after papermaking, they intertwine to form a paper sheet with a certain strength. In addition, the average fiber length is less than 10 mm, so the heat transfer distance of a single inorganic fiber is short, thus ensuring high thermal insulation.

[0016] Structure (3) The paper sheet also contains inorganic particles.

[0017] The sheet material contains inorganic particles, resulting in a short heat transfer distance per particle and high thermal resistance at the contact points, thus ensuring high thermal insulation. Furthermore, using high-refractive-index particles such as silica nanoparticles or titanium dioxide particles as inorganic particles facilitates surface reflection of light, particularly providing excellent shielding against radiative heat in high-temperature regions.

[0018] Structure (4) The paper sheet also contains a bonding material.

[0019] Because of the bonding material, it can prevent the first inorganic fibers and inorganic particles from falling off the paper sheet and maintain strength.

[0020] Furthermore, inorganic binders such as alumina sol and silica sol, and organic binders such as cationic starch and acrylic resin can be selected as bonding materials. These bonding materials are used as raw materials for papermaking in an aqueous solution state, and by drying them, the remaining inorganic fibers and inorganic particles are bonded together.

[0021] Structure (5) has an intermediate layer formed by the first inorganic fiber penetrating the fabric layer in the interface region between the fabric layer and the paper sheet layer.

[0022] Because of the intermediate layer formed by the first inorganic fiber penetrating the fabric layer, high peel strength is ensured. Furthermore, the fabric layer and the sheet layer are firmly bonded, making them difficult to peel even under repeated vibrations and external compressive forces; they are also unlikely to detach from the sides or top of the battery casing. Moreover, since both the fabric layer and the sheet layer are inorganic and bonded directly without the aid of organic materials, they will not peel off even when exposed to high temperatures, ensuring stable use.

[0023] Structure (6): The thickness of the paper sheet is 0.1-5 mm.

[0024] The thickness of the sheet material is 0.1 mm or more, thus providing high thermal insulation to the battery protection sheet. If the thickness of the sheet material is 5 mm or less, flexibility is ensured, allowing it to be bent into a specified shape for use. 0.2 to 1.1 mm is preferred.

[0025] Structure (7): The thickness of the fabric layer is 0.1-5 mm.

[0026] The fabric layer thickness is 0.1 mm or more, thus providing high mechanical strength to the battery protection sheet. If the fabric layer thickness is 5 mm or less, flexibility is ensured, allowing it to be bent along a specified shape for use. 0.3 to 1.4 mm is preferred.

[0027] Structure (8) has a first coating layer on the outside of the paper sheet.

[0028] If there is a first coating layer on the outside of the paper sheet, it can prevent the powder from falling off the paper sheet.

[0029] Structure (9), the first coating layer and the sheet layer are bonded by a first bonding layer made of an adhesive or thermoplastic resin.

[0030] If the first coating layer is fixed by the bonding layer, the first coating layer can be difficult to peel off even if external forces such as friction are applied.

[0031] Structure (10) has a second covering layer on the outside of the fabric layer.

[0032] If there is a second covering layer on the outside of the fabric layer, the fabric layer will not easily fall apart even if friction is applied to the ends of the fabric layer from the outside.

[0033] Structure (11), the second coating layer and the fabric layer are bonded by a second bonding layer made of adhesive or thermoplastic resin.

[0034] If the second coating layer is fixed by the second bonding layer, the ends are difficult to roll up, and even if external forces such as friction are applied, the fabric layer is not easy to disintegrate.

[0035] Furthermore, regarding the battery pack module of the present invention used to solve the aforementioned technical problem,

[0036] Structure (12) has: a plurality of battery packs; a housing that houses the battery packs; and a battery protection sheet of any one of structures (1) to (11) attached to the inside of the housing.

[0037] The battery pack module of the present invention has a battery protective sheet with excellent mechanical impact resistance and heat resistance on the inner side of the housing containing the battery pack. Therefore, it can protect the battery from external damage by protrusions, and can suppress heat transfer to the outside of the housing in case of battery malfunction to prevent damage to the housing. It can also prevent flammable materials from coming into contact with the outside air and burning violently, thus providing excellent safety.

[0038] Invention Effects

[0039] According to the present invention, a protective sheet for a battery can be provided, having a paper sheet layer containing a first inorganic fiber and a cloth layer composed of a second inorganic fiber. Therefore, the cloth layer has mechanical impact resistance, and the paper sheet layer has high thermal insulation, thus possessing both impact resistance and thermal insulation.

[0040] Furthermore, according to the present invention, a battery pack module is provided in which a battery protective sheet with excellent mechanical impact resistance and heat resistance is provided on the inner side of the housing containing the battery pack. Therefore, the battery can be protected from external damage by protrusions, and heat transfer to the outside of the housing can be suppressed to prevent damage to the housing when the battery is abnormal. It can also prevent flammable materials from coming into contact with the outside air and burning violently, thus providing excellent safety. Attached Figure Description

[0041] Figure 1 This is a cross-sectional view showing a battery protection sheet according to Embodiment 1 of the present invention.

[0042] Figure 2 express Figure 1 A magnified view of part A.

[0043] Figure 3 yes Figure 2 A magnified view of part B.

[0044] Figure 4 This is a cross-sectional view showing the battery protection sheet according to Embodiment 2 of the present invention.

[0045] Figure 5 This is a cross-sectional view showing the battery protection sheet according to Embodiment 3 of the present invention.

[0046] Figure 6 This is a cross-sectional view of a battery pack module that uses the battery protection sheet of the present invention.

[0047] Figure 7This is an explanatory diagram showing the method of shear test for battery protection sheets.

[0048] Label Explanation

[0049] 1: Battery protection film;

[0050] 10: Copying layers;

[0051] 11: First inorganic fiber;

[0052] 15: Inorganic particles;

[0053] 17: Based on the materials;

[0054] 20: Fabric layer;

[0055] 21: Second inorganic fiber;

[0056] 30: Intermediate layer;

[0057] 40: First bonding layer;

[0058] 50: First covering layer;

[0059] 60: Second bonding layer;

[0060] 70: Second overlying layer;

[0061] 100: Battery pack module;

[0062] 110: Battery pack;

[0063] 120: Battery casing;

[0064] 200: Battery protection film;

[0065] 210: Steel plate. Detailed Implementation

[0066] The present invention will now be described in detail with reference to the accompanying drawings.

[0067] <Battery Protection Sheet>

[0068] [Implementation Method 1]

[0069] like Figure 1 As shown, the battery protective sheet 1 has a sheet layer 10 and a cloth layer 20.

[0070] (1. Copying a layer)

[0071] Figure 2 It is Figure 1 The enlarged schematic diagram of part A shows that the fabricated sheet 10 includes a first inorganic fiber 11.

[0072] (1-1. First Inorganic Fiber)

[0073] For ease of fabrication, the first inorganic fiber 11 is preferably chopped or ground fiber. Furthermore, the first inorganic fiber 11 is preferably a fiber with excellent heat resistance, such as ceramic fibers like silica fiber, alumina fiber, aluminosilicate fiber, and zirconium oxide fiber, as well as glass fiber. These inorganic fibers can be used individually or in combination of two or more types.

[0074] In the case of mixed use, it is preferable that one of the fibers is amorphous and the other is composed of at least one type selected from crystalline fibers and amorphous fibers with a higher glass transition temperature than the first type of fiber. In this case, when the battery protection sheet 1 is exposed to high temperature, the surface of the first inorganic fiber softens earlier and bonds the second inorganic fiber, the inorganic particles 15 described later, thereby improving mechanical strength.

[0075] The average fiber length of the first inorganic fiber 11 is preferably 0.5 to 10 mm. The sheet 10 is obtained by forming a suspension containing the first inorganic fiber 11, but since the average fiber length is 0.5 mm or more, after forming, if... Figure 2 As shown, the first inorganic fibers contained in the papermaking sheet are irregularly interwoven, giving it a certain strength as a papermaking body. The term "papermaking" refers to: "dispersing short, fibrous inorganic fibers in a solvent (water), adding organic binders, inorganic binders, and pH adjusters to the mixture as needed, injecting the mixture into a forming device with a filter mesh on the bottom surface, and performing solvent removal treatment (dehydration treatment) on the mixture." Furthermore, the average fiber length of the first inorganic fiber 11 is less than 10 mm; therefore, the heat transfer distance of a single inorganic fiber is short, thus ensuring high thermal insulation.

[0076] (1-2. Inorganic particles)

[0077] The sheet 10 may also contain inorganic particles 15. Regarding each inorganic particle 15, the heat transfer distance is short and the thermal resistance at the contact point is high, thus ensuring high thermal insulation.

[0078] The material of the inorganic particles 15 is not particularly limited. From the viewpoint of heat transfer suppression effect, it is preferred to be composed of at least one of oxide particles, carbide particles, nitride particles and inorganic hydrate particles, and more preferably, oxide particles are included.

[0079] In addition, the shape and size of the inorganic particles 15 are not particularly limited, but preferably include at least one type selected from nanoparticles, hollow particles and porous particles, and more preferably include nanoparticles.

[0080] Furthermore, the inorganic particles 15 can be a single type of inorganic particle or a combination of two or more types. Using two or more types of inorganic particles with different heat transfer suppression effects allows for multi-stage cooling of the heating element, resulting in heat absorption over a wider temperature range. Additionally, a mixture of large-diameter and small-diameter particles is preferred. When small-diameter particles are inserted into the gaps between large-diameter particles, a denser structure is created, improving the heat transfer suppression effect.

[0081] If the average secondary particle size of the inorganic particles 15 is 0.01 μm or more, it is readily obtainable and can suppress the increase in manufacturing costs. Furthermore, if it is 200 μm or less, the desired heat insulation effect can be obtained. Therefore, the average secondary particle size of the inorganic particles 15 is preferably 0.01 μm or more and 200 μm or less, more preferably 0.05 μm or more and 100 μm or less.

[0082] The following is a detailed description of an example of the material or shape of particles that can be used as inorganic particles 15.

[0083] (1-2-1. Oxide particles)

[0084] Oxide particles have a high refractive index, resulting in strong light diffuse reflection. Therefore, when oxide particles are used as inorganic particles, they can suppress radiative heat transfer, especially in high-temperature regions such as those experiencing abnormal heating. At least one oxide particle selected from silicon dioxide, titanium dioxide, zircon, barium titanate, zinc oxide, and aluminum oxide can be used. That is, one or more of the aforementioned oxide particles that can be used as inorganic particles can be used. In particular, silicon dioxide is a component with high thermal insulation properties, and titanium dioxide is a component with a high refractive index compared to other metal oxides, resulting in a high effect of light diffuse reflection and shielding from radiative heat in high-temperature regions above 500°C. Therefore, it is most preferable to use at least one of silicon dioxide and titanium dioxide as oxide particles.

[0085] The particle size of oxide particles sometimes affects the effectiveness of reflecting radiative heat. Therefore, by limiting the average primary particle size to a specified range, higher thermal insulation can be obtained. That is, if the average primary particle size of the oxide particles is 0.001 μm or more, it is sufficiently large compared to the wavelength of light that facilitates heating, allowing for efficient diffuse reflection of light. Therefore, radiative heat transfer inside the battery protection sheet 1 in high-temperature regions above 500°C is suppressed, further improving thermal insulation. On the other hand, if the average primary particle size of the oxide particles is 50 μm or less, even when compressed, the number of contact points between particles does not increase, making it difficult to form conductive heat transfer pathways. Therefore, it is particularly effective in reducing the impact on thermal insulation in normal temperature regions where conductive heat transfer is dominant.

[0086] When using two or more types of oxide particles, it is also preferable to use a mixture of large-diameter particles and small-diameter particles (nanoparticles). In this case, the average primary particle size of the large-diameter particles is more preferably 1 μm or more and 50 μm or less, further preferably 5 μm or more and 30 μm or less, and most preferably 10 μm or less.

[0087] Furthermore, in this invention, the average primary particle size can be obtained by observing the particles under a microscope, comparing them with a standard scale, and taking the average of any 10 particles.

[0088] In this invention, nanoparticles refer to nanoscale particles that are spherical or nearly spherical with an average primary particle size of less than 1 μm. Because nanoparticles have low density, they can suppress conductive heat transfer. If nanoparticles are used as inorganic particles, the voids are further finely dispersed, thus achieving excellent thermal insulation properties that suppress convective heat transfer. Therefore, when used in typical ambient temperature ranges, nanoparticles are preferred in terms of suppressing heat conduction between adjacent nanoparticles.

[0089] Furthermore, in this invention, it is preferred that at least one of the oxide particles, carbide particles, nitride particles, and inorganic hydrate particles selected as inorganic particles 15 is a nanoparticle.

[0090] When using nanoparticles as inorganic particles 15, the material is not particularly limited as long as it meets the definition of nanoparticles mentioned above. For example, in addition to being a highly insulating material, silica nanoparticles also have small contact points between particles. Therefore, the heat conducted through silica nanoparticles is less compared to using silica particles with larger particle sizes. Furthermore, the bulk density of silica nanoparticles typically obtained is 0.1 g / cm³. 3 Therefore, even when a large compressive stress is applied to the battery protection sheet 1, the size (area) and number of contact points between the silica nanoparticles do not increase significantly, thus maintaining thermal insulation. Therefore, it is preferable to use silica nanoparticles as the nanoparticles. Wet silica, dry silica, and aerogel can be used as silica nanoparticles.

[0091] Furthermore, in this invention, it is preferred that at least one of the oxide particles, carbide particles, nitride particles, and inorganic hydrate particles selected as inorganic particles 15 be nanoparticles. As described above, titanium dioxide has a high effect on shielding radiant heat, and silicon dioxide nanoparticles have extremely low thermal conductivity, and can maintain excellent thermal insulation even when compressive stress is applied to the battery protective sheet 1. Therefore, it is most preferred to use both titanium dioxide and silicon dioxide nanoparticles as inorganic particles 15.

[0092] By limiting the average primary particle size of the nanoparticles to a specified range, higher thermal insulation can be achieved. Specifically, if the average primary particle size of the nanoparticles is set to be 1 nm or more and 100 nm or less, especially in temperature regions below 500°C, convective and conductive heat transfer within the battery protection sheet 1 can be suppressed, further improving thermal insulation. Furthermore, even under compressive stress, the voids remaining between the nanoparticles and the contacts between multiple particles can suppress conductive heat transfer, maintaining the thermal insulation of the battery protection sheet 1.

[0093] Furthermore, the average primary particle size of the nanoparticles is more preferably 2 nm or more, and even more preferably 3 nm or more. On the other hand, the average primary particle size of the nanoparticles is more preferably 50 nm or less, and even more preferably 10 nm or less.

[0094] (1-2-2. Inorganic hydrate particles)

[0095] When inorganic hydrate particles are heated by a heat source and reach a temperature above the initiation temperature of thermal decomposition, they undergo thermal decomposition, releasing their own water of crystallization and thus lowering the temperature of the heat source and its surroundings, exhibiting the so-called "endothermic effect." Furthermore, after releasing the water of crystallization, they become porous, exhibiting an insulating effect through numerous air pores.

[0096] Specific examples of inorganic hydrates include aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), calcium hydroxide (Ca(OH)2), zinc hydroxide (Zn(OH)2), iron hydroxide (Fe(OH)2), manganese hydroxide (Mn(OH)2), zirconium hydroxide (Zr(OH)2), and gallium hydroxide (Ga(OH)3).

[0097] For example, aluminum hydroxide contains about 35% water of crystallization. As shown in the following formula, it decomposes thermally to release the water of crystallization, exhibiting an endothermic effect. Furthermore, after releasing the water of crystallization, it becomes alumina (Al2O3), a porous material, which functions as a heat-insulating material.

[0098] 2Al(OH)3→Al2O3+3H2O

[0099] Furthermore, in battery packs experiencing thermal runaway, temperatures rise rapidly to over 200°C and continue to rise to around 700°C. Therefore, the inorganic particles are preferably composed of inorganic hydrates with a thermal decomposition start temperature of 200°C or higher. Regarding the thermal decomposition start temperatures of the aforementioned inorganic hydrates—aluminum hydroxide approximately 200°C, magnesium hydroxide approximately 330°C, calcium hydroxide approximately 580°C, zinc hydroxide approximately 200°C, iron hydroxide approximately 350°C, manganese hydroxide approximately 300°C, zirconium hydroxide approximately 300°C, and gallium hydroxide approximately 300°C—these temperatures largely overlap with the rapidly rising temperature range of battery cells experiencing thermal runaway, effectively suppressing temperature increases. Therefore, these inorganic hydrates can be considered preferred.

[0100] When inorganic hydrate particles are used, if their average particle size is too large, the inorganic hydrate particles located near the center of the sheet 10 will require a certain amount of time before reaching their thermal decomposition temperature. Therefore, sometimes the inorganic hydrate particles near the center of the sheet cannot be completely thermally decomposed. Therefore, the average secondary particle size of the inorganic hydrate particles is preferably 0.01 μm or more and 200 μm or less, more preferably 0.05 μm or more and 100 μm or less.

[0101] (1-3. Based on the materials)

[0102] The preferred sheet material 10 also contains a bonding material 17. Figure 3 It is Figure 2 The enlarged schematic diagram of part B shows that it can prevent the first inorganic fiber 11, and thus prevent the inorganic particles 15 (not shown) from falling off the sheet 10, and can maintain strength.

[0103] As the bonding material 17, inorganic binders such as alumina sol and silica sol, and organic binders such as cationic starch and acrylic resin can be selected. These bonding materials 17 are used as raw materials for papermaking sheets 10 in an aqueous solution state, and are bonded together by drying the residue at the contact points of the first inorganic fiber 11 and inorganic particles 15.

[0104] (1-4. Composition of the sheet material)

[0105] When the paper sheet 10 comprises inorganic particles 15 and bonding material 17, it is preferable that, relative to the total amount of the paper sheet 10, the inorganic particles 15 are 30-94% by mass, the bonding material 17 is 0-10% by mass, and the remainder is the first inorganic fiber 11. By setting it to this composition, the effects of the aforementioned inorganic particles 15 and bonding material 17 can be obtained in a balanced manner.

[0106] (1-5. Thickness of the sheet)

[0107] The thickness of the sheet 10 is preferably 0.1 to 5 mm. When the thickness of the sheet 10 is 0.1 mm or more, high heat insulation can be imparted to the battery protection sheet 1. Furthermore, if the thickness of the sheet 10 is 5 mm or less, flexibility can be ensured, allowing the battery protection sheet 1 to be bent along a predetermined shape for use. Preferably, it is 0.2 to 1.1 mm.

[0108] (2. Fabric layers)

[0109] like Figure 2 As shown, the fabric layer 20 is a layer obtained by weaving the second inorganic fiber 21 as the horizontal thread 21a and the vertical thread 21b into a fabric shape. The second inorganic fiber 21 is a continuous fiber that can form a fabric, and the long fiber length is utilized to ensure the high strength of the battery protection sheet 1.

[0110] (2-1. Second inorganic fiber)

[0111] As the second inorganic fiber 21, similar to the first inorganic fiber 11, examples include ceramic fibers such as silica fiber, alumina fiber, aluminosilicate fiber, and zirconium oxide fiber, as well as glass fiber. These inorganic fibers can be used individually or in combination of two or more types.

[0112] Furthermore, the second inorganic fiber 21 and the first inorganic fiber 11 can be of the same type or different types of inorganic fibers. In either case, they are combinations of inorganic materials, and the battery protective sheet 1 exhibits excellent heat resistance.

[0113] (2-2. Thickness of the fabric layer)

[0114] The thickness of the fabric layer 20 is preferably 0.1 to 5 mm. When the thickness of the fabric layer 20 is 0.1 mm or more, high mechanical strength can be imparted to the battery protection sheet 1. If the thickness of the fabric layer 20 is 5 mm or less, flexibility can be ensured, allowing the battery protection sheet 1 to be bent along a predetermined shape for use. Preferably, it is 0.3 to 1.4 mm.

[0115] (3. Intermediate layer)

[0116] like Figure 2 As shown, preferably, in the interface region between the paper sheet 10 and the fabric layer 20, the first inorganic fiber 11 of the paper sheet 10 penetrates into the weave of the second inorganic fiber 21 of the fabric layer 20 to form an intermediate layer 30.

[0117] The second inorganic fiber 21 penetrates the fabric layer 20, thus ensuring high peel strength. Furthermore, the fabric layer 20 is firmly bonded to the sheet layer 10, making it difficult to peel off even when subjected to repeated vibrations or external compressive forces, and even preventing detachment from the sides or top of the inner wall of the battery casing 120 of the battery module 100 (described later). Moreover, since both the fabric layer 20 and the sheet layer 10 are inorganic materials and are directly bonded without the aid of organic materials, the battery protective sheet 1 will not peel off even when exposed to high temperatures, ensuring stable use.

[0118] (4. Manufacturing method of battery protection film)

[0119] The first inorganic fiber 11 will become the raw material for making the sheet 10, and the inorganic particles 15 and the binding material 17 will be added to water in a specified ratio to prepare a suspension.

[0120] The suspension is allowed to flow into one side of the fabric layer 20. After drainage and dehydration, it is pressurized and vacuum dried. Thus, with the first inorganic fiber 11 of the fabric layer 10 penetrating the weave of the second inorganic fiber 21 of the fabric layer 20, the fabric layer 20 and the fabric layer 10 are joined to obtain the battery protective sheet 1.

[0121] [Implementation Method 2]

[0122] like Figure 4 As shown, in addition to the sheet 10 and the cloth layer 20, the battery protective sheet 1 may also have a first coating layer 50 attached to the outside of the sheet 10, separated by a first bonding layer 40. The first coating layer 50 prevents powder (the solidified product of the first inorganic fiber 11, inorganic particles 15, and bonding material 17) from falling off the sheet 10. Furthermore, if the first coating layer 50 is fixed by the first bonding layer 40, it is difficult to peel off even when external forces such as friction are applied.

[0123] (1. First bonding layer)

[0124] The first bonding layer 40 is not particularly limited as long as it can bond the first inorganic fiber 11 and inorganic particles 15 constituting the paper sheet 10 to the forming material of the first coating layer 50 described later. For example, various adhesives, thermoplastic resins, double-sided tapes, etc. can be used.

[0125] (2. First covering layer)

[0126] The first coating layer 50 can be made of resins such as polypropylene, paper, etc., and can be made of films or cloths composed of them.

[0127] Additionally, as shown in the figure, it is preferable to have a second coating layer 70 on the outside of the fabric layer 20, separated by a second bonding layer 60. Through the second coating layer 70, even if friction is applied to the ends of the fabric layer 20 from the outside, it is difficult for it to come apart.

[0128] Furthermore, the second bonding layer 60 and the second coating layer 70 can be made of the same materials as the first bonding layer 40 and the first coating layer 50 described above.

[0129] [Implementation Method 3]

[0130] like Figure 5 As shown, in addition to the sheet layer 10 and the cloth layer 20, the battery protective sheet 1 may also have a first coating layer 50 attached to the outside of the sheet layer 10. Furthermore, a second coating layer 70 may also be attached to the outside of the cloth layer 20. The details and effects of the first coating layer 50 and the second coating layer 70 are the same as in Embodiment 2.

[0131] However, since the first coating layer 50 and the second coating layer 70 are directly attached to the surface of the paper sheet or the fabric layer 20 without passing through a bonding layer, the state in which a part of the first coating layer 50 melts and bonds with the paper sheet, or a part of the second coating layer 70 melts and bonds with the fabric layer 20, can be applied to the first coating layer 50 or the second coating layer 70 using a resin or the like with a softening point.

[0132] <Battery Pack Module>

[0133] like Figure 6 As shown, the battery module 100 is configured such that the aforementioned battery protective sheet 1 is attached to the entire inner surface (top, side walls, and bottom) of the battery housing 120 that houses multiple battery packs 110. Furthermore, during attachment, either the paper sheet layer 10 or the cloth layer 20 can be positioned on the housing side relative to the battery housing 120.

[0134] In the battery pack module 100, since the battery protection sheet 1 is attached internally, it can protect the battery pack 110 from external damage by protrusions, and prevent damage by suppressing heat transfer to the outside of the battery casing 120 when the battery pack 110 is abnormal. It can also prevent flammable materials such as organic electrolytes in the battery pack 110 from coming into contact with the outside air and burning violently. It has high safety.

[0135] [Example]

[0136] (Example 1)

[0137] The materials were weighed as follows: glass fiber as the first inorganic fiber (11% by mass), silica nanoparticles and titanium dioxide as inorganic particles (80% by mass, 56% by mass for silica nanoparticles (average particle size 5 nm), 24% by mass for titanium dioxide (average particle size 8 μm), and acrylic resin as the binding material (5% by mass). These were added to water and stirred thoroughly to prepare a suspension. The suspension was then applied to one side of a silica fiber cloth (1.36 mm thick, 4% by mass) for dehydration, pressurization, and vacuum drying to produce a battery protective sheet composed of a laminated sheet and a cloth layer. The thickness of the laminated sheet was 1.0 mm.

[0138] (Example 2)

[0139] In Example 1, a polypropylene film is bonded to both sides of the battery protective sheet to form a first coating layer and a second coating layer via double-sided adhesive. Pressure is applied from both sides to produce the battery protective sheet.

[0140] (Evaluation Test)

[0141] An evaluation based on a peel test was conducted on the battery protection sheet of Example 1 and the battery protection sheet of Example 2. That is, as... Figure 7 As shown, the battery protective sheet 200 is attached to two steel plates 210 using double-sided tape. The plates are then stretched in the vertical direction as shown in the figure, and the shear force at which the plates are peeled off is measured.

[0142] The measurement results show that, in the battery protection sheet of Example 1, the [N / cm] ratio is 15. 2 The shear force of 90 N / cm² caused peeling within the sheet. In contrast, in the battery protective sheet of Example 2, the shear force was 90 N / cm². 2 The shear force of the material causes the double-sided adhesive to peel off between the steel plate 210 and the polypropylene film on the fabric side.

[0143] Therefore, it can be confirmed that in the battery protective sheets of Examples 1 and 2, the sheet layer and the cloth layer are fully bonded to obtain an integrated battery protective sheet with mechanical impact resistance and high heat insulation.

[0144] Therefore, it can be seen that in the battery protective sheet of Example 2, the adhesion between the textured sheet and the polypropylene film is stronger, resulting in a firm bond. Furthermore, when manufacturing the battery module, it can be said that by placing the textured sheet on the casing side, a stronger bond can be obtained.

Claims

1. A protective sheet for batteries, comprising: The sheet material contains a first inorganic fiber; and The fabric layer is composed of a second inorganic fiber. At the interface region between the fabric layer and the sheet layer, there is an intermediate layer formed by the first inorganic fiber penetrating the weave of the second inorganic fiber in the fabric layer. The first inorganic fiber is used in combination with two or more types. The first inorganic fiber is selected from ceramic fibers and glass fibers. The ceramic fibers are selected from silica fibers, alumina fibers, aluminosilicate fibers, and zirconium oxide fibers. Among the first inorganic fibers, one type of fiber is an amorphous fiber, and the other type of fiber is composed of at least one type selected from crystalline fibers and amorphous fibers with a glass transition temperature higher than that of the first type of fiber. The sheet material also contains inorganic particles, which are dispersed between the first inorganic fibers.

2. The battery protection sheet according to claim 1, characterized in that, The average fiber length of the first inorganic fiber is 0.5~10mm.

3. The battery protection sheet according to claim 1 or 2, characterized in that, The paper sheet also contains a bonding material.

4. The battery protection sheet according to claim 1 or 2, characterized in that, The thickness of the paper sheet is 0.1~5mm.

5. The battery protection sheet according to claim 1 or 2, characterized in that, The thickness of the fabric layer is 0.1~5mm.

6. The battery protection sheet according to claim 1 or 2, characterized in that, The outer side of the paper sheet has a first coating layer.

7. The battery protection sheet according to claim 6, characterized in that, The first coating layer is bonded to the sheet layer by a first bonding layer made of an adhesive or thermoplastic resin.

8. The battery protection sheet according to claim 1 or 2, characterized in that, A second covering layer is provided on the outside of the fabric layer.

9. The battery protection sheet according to claim 8, characterized in that, The second coating layer is bonded to the fabric layer by a second bonding layer made of an adhesive or thermoplastic resin.

10. A battery pack module, comprising: Multiple battery packs; A housing that contains the battery pack; and The battery protective sheet according to any one of claims 1 to 9 is attached to the inside of the housing.

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