Protective cover and battery module

Abstract

The utility model provides a protective cover and a battery module, which can improve the adhesion between a heat insulation piece and a specified surface such as the inner wall surface of a battery shell. The protective cover (10) has: a heat insulating material (1) containing first organic fibers (3); and an organic film (2) adhered to at least a part of the surface of the heat insulating material (1). At least a part of the first organic fibers (3) protrude from the surface of the heat insulating material (1). The battery module (100) is provided with the protective cover (10), a storage battery (110), and a battery case (120) for accommodating the protective cover (10) and the storage battery (110).

Description

Technical Field

[0001] The utility model relates to a protective cover and a battery module provided with the protective cover. Background Art

[0002] In recent years, lithium ion secondary batteries have been used in electric vehicles, etc., for environmental protection. However, lithium ion secondary batteries use organic electrolytes, so if they catch fire during thermal runaway, there is a possibility that flames will be generated and the battery pack will be damaged.

[0003] As a countermeasure, for example, a thermal runaway suppression refractory sheet having excellent fire resistance and heat insulation is proposed in Patent Document 1. The refractory sheet comprises a substrate and an inorganic particle layer containing inorganic particles and an inorganic binder, wherein the substrate contains glass fibers, wet heat adhesive binder fibers, and fibrillated heat-resistant fibers. In addition, the inorganic particle layer has a coating layer covering the surface of the fibers contained in the substrate and a heat insulation layer present on at least one side of the substrate surface.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-96935 Utility Model Content

[0007] Technical problems to be solved by the utility model

[0008] In addition, in order to prevent the fire from spreading to the outside of the battery module, if the fire-resistant sheet is to be bonded to the wall and top surface of the battery case that contains the battery, there is a problem that the adhesion between the fire-resistant sheet and the inner wall surface of the battery case is extremely weak. In this way, if the adhesion between the fire-resistant sheet and the specified surface is weak, the fire-resistant sheet is easy to fall off in the event of a fire caused by thermal runaway of the battery, and the fire-resistant effect and heat-insulating effect of the fire-resistant sheet cannot be obtained. As a result, there is a possibility of danger to surrounding objects and people.

[0009] The present invention is completed in view of the above technical problems, and its purpose is to provide a protective cover and a manufacturing method thereof, and a battery module, which can improve the adhesion between a heat insulating member and a predetermined surface such as the inner wall surface of a battery case.

[0010] Means for solving technical problems

[0011] The above-mentioned object of the utility model is achieved by the following structure [1] involving the protective cover.

[0012] [1]. A protective cover, characterized in that it has:

[0013] A thermal insulation member comprising fibers; and

[0014] an organic film bonded to at least a portion of the surface of the thermal insulation member,

[0015] At least a portion of the first organic fibers protrude from a surface of the thermal insulation member.

[0016] In addition, preferred embodiments of the present invention regarding the protective cover relate to the following [2] to [9].

[0017] [2] In the protective cover of [1], the fiber is composed of at least one of a first organic fiber and an inorganic fiber.

[0018] [3] In the protective cover of [1] or [2], it is characterized in that

[0019] The thermal insulation member includes the first organic fibers and second organic fibers different from the first organic fibers.

[0020] [4] In the protective cover of [2] or [3], it is characterized in that

[0021] The first organic fiber is polyethylene terephthalate fiber,

[0022] The second organic fiber is vinylon fiber.

[0023] [5] In the protective cover of any one of [1] to [4], it is characterized in that

[0024] The fibers protruding from the surface of the thermal insulator are fused to the organic film.

[0025] [6] In the protective cover of any one of [1] to [5], it is characterized in that

[0026] The thermal insulation member has a first surface and a second surface which are opposite to each other.

[0027] The organic film is disposed on the first surface.

[0028] An inorganic fiber layer is disposed on the second surface.

[0029] [7] In the protective cover of [6], it is characterized in that

[0030] The thermal insulation material and the inorganic fiber layer are bonded together via an adhesive layer.

[0031] [8] In the protective cover of [6] or [7], it is characterized in that the thermal insulation member and the inorganic fiber layer are covered by the organic film.

[0032] [9] In the protective cover of any one of [6] to [8], it is characterized in that

[0033] The inorganic fiber layer is obtained by processing at least one selected from silica fiber, alumina fiber, glass fiber and metal fiber into a layered shape.

[0034] The above-mentioned object of the utility model is achieved by the following structure

[10] involving the battery module.

[0035]

[10] A battery module, characterized by comprising: a protective cover according to any one of [1] to [9];

[0036] Batteries; and

[0037] A battery case houses the protective cover and the storage battery.

[0038] In addition, a preferred embodiment of the present invention regarding a battery module relates to the following

[11] .

[0039]

[11] . In the battery module of

[10] , it is characterized in that

[0040] The battery housing has a top surface, a side wall surface and a bottom wall surface inside.

[0041] The organic film in the protective cover is bonded to at least one selected from the top surface, the side wall surface, and the bottom wall surface, and the protective cover is installed in the battery case.

[0042] Utility Model Effect

[0043] In the protective cover of the present invention, the first organic fibers protruding from the surface of the heat insulating material are firmly bonded to the organic film, and the organic film has excellent adhesion to other surfaces, so that the adhesion between the heat insulating material and a predetermined surface can be improved.

[0044] Furthermore, the battery module of the present invention has the protective cover of the present invention bonded to the battery housing that accommodates the battery, so that the protective cover can be prevented from falling down during thermal runaway. Therefore, the heat insulation of the heat insulating member can be maintained, and even if a flame is generated, it can be more reliably prevented from spreading to the outside. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram showing the protection cover according to the first embodiment of the present invention.

[0046] Figure 2 It is a schematic diagram showing a protective cover according to a second embodiment of the present invention.

[0047] Figure 3 It is a schematic cross-sectional view showing a protective cover according to a third embodiment of the present invention.

[0048] Figure 4It is a schematic cross-sectional view showing a battery module according to an embodiment of the present invention.

[0049] Description of Reference Numerals

[0050] 1: Thermal insulation;

[0051] 2, 12: organic film;

[0052] 3: First organic fiber;

[0053] 4: second organic fiber;

[0054] 5: contact area;

[0055] 6: Inorganic particles;

[0056] 7: Inorganic fiber layer;

[0057] 8: Inorganic particles;

[0058] 10, 20: protective cover;

[0059] 100: battery module;

[0060] 110: Battery;

[0061] 120: Battery casing. DETAILED DESCRIPTION

[0062] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the present invention is not limited to the embodiments described below, and can be implemented with arbitrary changes within the scope not departing from the gist of the present invention.

[0063] [Protective cover]

[0064] <First Embodiment>

[0065] Figure 1Schematic diagram of a protective cover according to a first embodiment of the present invention. The protective cover 10 has a heat insulating material 1 and an organic film 2. The heat insulating material 1 includes a first organic fiber 3 and a second organic fiber 4 as fibers, and includes inorganic particles 6. In addition, the first organic fiber 3 and the second organic fiber 4 protrude from the first surface 1a of the opposite main surface of the heat insulating material 1. Specifically, on the first surface 1a of the heat insulating material 1, there are formed: a protrusion 3a formed by embedding one end of the first organic fiber 3 in the heat insulating material 1 and only protruding from the other end; a protrusion 3b formed by embedding both ends in the heat insulating material 1 and only the central area protruding in an annular shape; and a protrusion 3c formed by only a part of the surface of the first organic fiber 3 protruding from the first surface 1a of the heat insulating material 1. In addition, there are also protrusions 4a formed by embedding one end of the second organic fiber 4 in the heat insulating material 1 and only the other end protruding from the first surface 1a, and protrusions 4c formed by only a part of the surface of the second organic fiber 4 protruding from the first surface 1a of the heat insulating material 1. Although not shown in the figure, the second organic fiber 4 may have a protrusion formed by protruding in a ring shape in only the central region. Furthermore, the protrusions 3a, 3b, and 3c of the first organic fiber 3 and the protrusions 4a and 4c of the second organic fiber 4 are bonded to the organic film 2 by an adhesive not shown in the figure, thereby bonding the organic film 2 to at least a portion of the surface of the thermal insulation member 1.

[0066] Here, if a general heat insulating material is to be bonded to an organic film, the bonding property to the organic film is significantly reduced depending on the surface state of the heat insulating material, and it is difficult to bond the two with a high bonding force. Figure 1 In the embodiment, the surface of the thermal insulation material 1 is flat, but the surface of the actual thermal insulation material has unevenness, and the unevenness of the thermal insulation material formed by papermaking is particularly large, so it is extremely difficult to bond the thermal insulation material to the organic film. In addition, in the present embodiment, the thermal insulation material 1 has inorganic particles 6, and the surface of the thermal insulation material 1 is in a state where powdery particles are attached, so the adhesion to other adhesive substances is significantly reduced.

[0067] On the other hand, Figure 1In the protective cover 10 involved in the first embodiment shown, a part of the first organic fiber 3 and the second organic fiber 4 is buried in the interior of the heat insulating member 1, and a part of them protrudes from the first surface 1a of the heat insulating member 1, forming protrusions 3a, 3b, 3c, 4a, 4c. In addition, since the first organic fiber 3 and the second organic fiber 4 are flexible, when the heat insulating member 1 and the organic film 2 are overlapped, the protrusions 3a, 3b, 3c, 4a, 4c are in a state of falling down in a direction substantially parallel to the first surface 1a in the first surface 1a of the heat insulating member 1. Therefore, the contact area 5 between the first organic fiber 3 and the second organic fiber 4 and the organic film 2 becomes larger than before, and a high bonding force can be obtained between the heat insulating member 1 and the organic film 2. Therefore, when it is desired to bond the heat insulating member 1 to, for example, a predetermined surface, the organic film 2 can be bonded to another surface using an adhesive, an adhesive tape, or the like. As a result, the heat insulating material 1 can be bonded to another surface with a high adhesive force via the organic film 2 , and the heat insulating material 1 can be prevented from peeling off from a predetermined surface.

[0068] In addition, if Figure 1 As shown, if the ends of both the first organic fibers 3 and the second organic fibers 4 are embedded in the thermal insulation material 1, the first organic fibers 3 and the second organic fibers 4 can be suppressed from falling out of the thermal insulation material 1. In addition, the first organic fibers 3 and the second organic fibers 4 embedded in the thermal insulation material 1 are sometimes intertwined with other first organic fibers 3 and second organic fibers 4 in the thermal insulation material 1. Thus, the first organic fibers 3 and the second organic fibers 4 can be further suppressed from falling out of the thermal insulation material.

[0069] In the present embodiment, the thermal insulation member 1 and the organic film 2 are bonded by an adhesive, but the bonding method of the present invention is not limited to the adhesive. For example, a method of overlapping the thermal insulation member 1 and the organic film 2 and then heating and pressurizing the two in the thickness direction may also be used. The first organic fiber 3, the second organic fiber 4, and the organic film 2 are all composed of organic materials, so they are melted and pressurized by heating, so that the two are welded. Therefore, as shown in the present embodiment, by increasing the contact area 5, the welding area is also increased, and the thermal insulation member 1 and the organic film 2 can be bonded with a higher bonding force.

[0070] In this embodiment, the thermal insulation material 1 includes the first organic fiber 3, the second organic fiber 4 and the inorganic particles 6, but the present invention is not limited to such a structure. The thermal insulation material only needs to include fibers composed of at least one of the first organic fiber 3 and the inorganic fiber. The following describes an embodiment in which the thermal insulation material has inorganic fibers.

[0071] <Second Embodiment>

[0072] Figure 2 Schematic diagram showing a protective cover according to a second embodiment of the present invention. Figure 2In the second embodiment shown, Figure 1 The same components as the protective cover of the first embodiment shown are marked with the same reference numerals, and their detailed description is omitted or simplified. The protective cover 15 of the second embodiment has a heat insulating member 11 and an organic film 2. The heat insulating member 11 contains inorganic fibers 16 as fibers and contains inorganic particles 6. As in the first embodiment, the inorganic fibers 16 protrude from the first surface 1a of the opposite main surfaces of the heat insulating member 11. Specifically, there are formed: a protrusion 16a formed by protruding only one end, a protrusion 16b formed by protruding only the central area in an annular shape, and a protrusion 16c formed by protruding only a part of the surface of the inorganic fiber 16. Moreover, the protrusions 16a, 16b and 16c of the inorganic fiber 16 are bonded to the organic film 2 by an adhesive not shown in the figure, thereby bonding the organic film 2 to at least a part of the surface of the heat insulating member 11.

[0073] In the protective cover 15 of the second embodiment thus constructed, a part of the protrusions 16a, 16b, and 16c are embedded in the heat insulating material 11, and a part of them are bonded to the organic film, so that a high bonding strength can be obtained between the heat insulating material 11 and the organic film 2. In addition, the inorganic fiber 16 is heat-resistant and does not melt even when heated, so even when the protective cover 15 in which the heat insulating material 11 and the organic film 2 are bonded by an adhesive is exposed to a high-temperature environment, a high bonding strength can be maintained. In addition, even when the heat insulating material 11 does not contain organic fibers, after the heat insulating material 11 and the organic film 2 are overlapped, the heat insulating material 11 and the organic film 2 can be pressed in the thickness direction while being heated, so that the surface of the organic film 2 is melted and the inorganic fiber 16 and the organic film 2 are bonded.

[0074] exist Figure 2 In the second embodiment shown, the thermal insulation material 11 may further include the first organic fibers 3 and the second organic fibers 4. If the thermal insulation material includes the inorganic fibers 16 and the organic fibers, the organic fibers can be fused to the organic film 2, and the thermal insulation material 11 and the organic film 2 can be firmly bonded. In addition, the inorganic fibers protruding from the first surface 11a of the thermal insulation material 11 and the organic fibers are interwoven on the surface of the thermal insulation material 11, thereby obtaining a higher bonding force between the thermal insulation material 11 and the organic film 2.

[0075] <Third Embodiment>

[0076] Figure 3 2 is a schematic cross-sectional view showing a protective cover 20 according to a third embodiment of the present invention. Figure 3 In the third embodiment shown, Figure 1The same components as those in the first embodiment are denoted by the same reference numerals, and their detailed description is omitted or simplified. The protective cover 20 includes a heat insulating member 1, an organic film 2 bonded to a first surface 1a as an opposite main surface of the heat insulating member 1, and an inorganic fiber layer 7 bonded to a second surface 1b as another opposite main surface of the heat insulating member 1. In addition, the protective cover 20 has an organic film 12 bonded to the surface of the inorganic fiber layer 7 on the opposite side to the surface on the heat insulating member 1 side. In addition, the bonding structure between the heat insulating member 1 and the organic film 2 is the same as that in the first embodiment, and therefore the illustration is omitted.

[0077] In the protective cover 20 according to the third embodiment thus constructed, similarly to the first embodiment, a high adhesive force can be obtained between the heat insulating material 1 and the organic film 2. In addition, since the inorganic fiber layer 7 is provided on the second surface 1b side of the heat insulating material 1, when objects are damaged or scattered around the protective cover 20, the heat insulating material 1 can be protected by the inorganic fiber layer 7. Therefore, damage to the heat insulating material 1 can be suppressed, and excellent heat insulating effect and fire prevention effect can be maintained.

[0078] Furthermore, since the protective cover 20 of the present embodiment has the organic film 2 and the organic film 12 on the outermost side, when the heat insulating material 1 has inorganic particles, for example, it is possible to prevent the inorganic particles from falling off.

[0079] In addition, depending on the manufacturing method of the thermal insulation member 1, more fibers may protrude from one of the pair of main surfaces, for example, the first surface 1a side. In such a case, if the organic film 2 is bonded to the first surface 1a side, excellent bonding between the thermal insulation member 1 and the organic film 2 can be obtained.

[0080] In the protective cover of the present invention, the heat insulating member includes fibers composed of at least one of the first organic fiber and the inorganic fiber, and the fibers protrude to form a protrusion. Thus, a contact area 5 can be ensured between the protrusion and the organic film 2, and the heat insulating member 1 and the organic film 2 can be bonded with a high bonding force. In addition, the inorganic fiber layer 7 and the organic film 12 further stacked on the heat insulating member 1 are not necessary and can be freely selected. In addition, in Figure 3 In the third embodiment shown, the heat insulating material 1 including the first organic fibers 3 and the second organic fibers is used, but as shown in the second embodiment, the heat insulating material 11 including the inorganic fibers 16 may be used. In addition, the heat insulating material including the first organic fibers 3 and the second organic fibers and the inorganic fibers 16, or the heat insulating material including only the first organic fibers 3 may be used.

[0081] In the third embodiment, the organic film 2 and the organic film 12 have different effects, but can be made of the same organic material or different organic materials. Furthermore, the laminate of the thermal insulation member 1 and the inorganic fiber layer 7 can be completely covered by the organic film, that is, the laminate can be wrapped inside by the organic film.

[0082] As shown in the first and second embodiments, for example, when the organic film 2 is bonded to a predetermined surface, an adhesive force that can at least support the weight of the thermal insulation material 1 is required between the thermal insulation material 1 and the organic film 2. However, as shown in the third embodiment, an adhesive force that can only support the weight of the organic film 12 is sufficient between the inorganic fiber layer 7 and the organic film 12, so it is not necessary to bond the inorganic fiber layer 7 and the organic film 12 with a high adhesive force. Therefore, the inorganic fiber layer 7 and the organic film 12 can be bonded by a common method, such as an adhesive or thermal fusion.

[0083] Hereinafter, materials such as the heat insulating material 1 , the organic film 2 , the inorganic fiber layer 7 , and the adhesive that constitute the protective cover 10 of the present embodiment will be described in detail.

[0084] 〔Thermal insulation〕

[0085] The heat insulating material 1 used in the protective cover 10 of the present embodiment is not particularly limited as long as it has the first organic fiber 3 and can obtain a heat insulating effect. As an indicator of the heat insulating effect, thermal conductivity can be cited, but in the present embodiment, the thermal conductivity of the heat insulating material 1 is preferably less than 1 (W / m·K), more preferably less than 0.5 (W / m·K), and more preferably less than 0.2 (W / m·K). Furthermore, the thermal conductivity of the heat insulating material 1 is more preferably less than 0.1 (W / m·K), more preferably less than 0.05 (W / m·K), and particularly preferably less than 0.02 (W / m·K).

[0086] The thermal conductivity of the heat insulating material 1 can be measured in accordance with "Testing method for thermal conductivity of refractories" described in JIS R 2251.

[0087] The thermal insulating material 1 includes at least one of the first organic fibers 3 and the inorganic fibers 16, and as other components, a component containing at least one selected from inorganic particles, second organic fibers, and organic particles can be used. Specific examples are shown below.

[0088] (First Organic Fiber)

[0089] In this embodiment, the organic material constituting the first organic fiber 3 is not particularly limited, and is preferably an organic fiber composed of an organic material having a high melting point and being non-water-soluble (hydrophobic). When a hydrophobic organic fiber is used as the first organic fiber 3, the bonding force between the first organic fiber 3 and the organic film 2 can be further improved. As the first organic fiber 3, for example, polyethylene terephthalate fiber can be used.

[0090] (Second organic fiber)

[0091] The material of the thermal insulation member 1 of the protective cover 10 of the present embodiment preferably includes a second organic fiber 4 having properties different from those of the first organic fiber 3. There is no particular limitation on the organic material constituting the second organic fiber 4 as long as it is different from the organic material constituting the first organic fiber 3, but it is preferably an organic fiber composed of a hydrophilic organic material. If a hydrophilic organic fiber is used as the second organic fiber 4, the formability of the thermal insulation member 1 can be improved. In addition, in the case where the thermal insulation member 1 contains various particles (powders) and the like, the second organic fiber 4 can improve the retention of the particles and inhibit the falling of the particles. As the second organic fiber 4, for example, vinylon fibers and the like can be used.

[0092] (Organic fiber content)

[0093] If the contents of the first organic fibers 3 and the second organic fibers 4 in the thermal insulation material 1 are appropriately controlled, the effects of the above-described respective fibers can be sufficiently obtained.

[0094] In order to obtain excellent adhesion between the thermal insulation material 1 and the organic film 2 and to maintain the moldability and thermal insulation properties of the thermal insulation material 1, it is preferred to appropriately adjust the content of the first organic fiber relative to the total mass of the thermal insulation material.

[0095] In this embodiment, the second organic fiber 4 may not be included in the thermal insulation member 1, but in order to improve the formability of the thermal insulation member 1, obtain the particle retention effect, and maintain the formability and thermal insulation of the thermal insulation member 1, the content of the second organic fiber relative to the total mass of the thermal insulation member is preferably appropriately adjusted.

[0096] (Fiber length of organic fibers)

[0097] The fiber length of the organic fibers is not particularly limited, but from the viewpoint of ensuring moldability and processability, the average fiber length of the organic fibers is preferably 10 mm or less.

[0098] On the other hand, from the viewpoint of allowing the organic fibers to function as a skeleton and ensuring the compressive strength of the thermal insulating material, the average fiber length of the organic fibers is preferably 0.5 mm or more.

[0099] <Inorganic Fiber>

[0100] The thermal insulation member 1 in the protective cover 10 involved in the present embodiment may include inorganic fibers instead of the above-mentioned organic fibers as fibers, or may include inorganic fibers as fibers together with the above-mentioned organic fibers. By including inorganic fibers, the thermal insulation of the thermal insulation member can also be improved. As inorganic fibers, a single inorganic fiber can be used, or two or more inorganic fibers can be used in combination. As inorganic fibers, for example, there can be listed: silica fibers, alumina fibers, aluminum silicate fibers, zirconium oxide fibers, carbon fibers, soluble fibers, refractory ceramic fibers, aerogel composite materials, magnesium silicate fibers, alkaline earth silicate fibers, potassium titanate fibers, silicon carbide fibers, potassium titanate whisker fibers and other ceramic fibers, glass fibers, glass wool, slag wool and other glass fibers, rock wool, basalt fibers, wollastonite, mullite fibers and other natural mineral fibers, etc.

[0101] These inorganic fibers are preferred in terms of heat resistance, strength, availability, etc. Among the inorganic fibers, from the viewpoint of handling properties, it is particularly preferred that the inorganic fibers be composed of at least one selected from silica fibers, alumina fibers, aluminum silicate fibers, zirconia fibers, glass fibers, and mineral fibers other than these fibers.

[0102] The cross-sectional shape of the inorganic fiber is not particularly limited, and examples thereof include circular cross-section, flat cross-section, hollow cross-section, polygonal cross-section, core cross-section, etc. Among them, fibers with a hollow cross-section, flat cross-section or polygonal cross-section are preferably used because they have slightly higher heat insulation properties.

[0103] (Average fiber length of inorganic fibers)

[0104] The preferred lower limit of the average fiber length of the inorganic fibers is 0.1 mm, and the more preferred lower limit is 0.5 mm. On the other hand, the preferred upper limit of the average fiber length of the inorganic fibers is 50 mm, and the more preferred upper limit is 10 mm. If the average fiber length of the inorganic fibers is less than 0.1 mm, it is difficult to produce entanglement between the inorganic fibers, and the mechanical strength of the thermal insulation may be reduced. On the other hand, if the average fiber length of the inorganic fibers exceeds 50 mm, although a reinforcement effect can be obtained, the inorganic fibers can be tightly entangled with each other, or curled only by a single inorganic fiber, which may lead to a reduction in thermal insulation.

[0105] The preferred lower limit of the average fiber diameter of the inorganic fibers is 1 μm, the more preferred lower limit is 2 μm, and the further preferred lower limit is 3 μm. On the other hand, the preferred upper limit of the average fiber diameter of the inorganic fibers is 15 μm, and the more preferred upper limit is 10 μm. When the average fiber diameter of the inorganic fibers is less than 1 μm, the mechanical strength of the inorganic fibers themselves may be reduced. In addition, from the viewpoint of the impact on human health, the average fiber diameter of the inorganic fibers is preferably greater than 3 μm. On the other hand, when the average fiber diameter of the inorganic fibers is greater than 15 μm, the solid heat transfer using the inorganic fibers as the medium will increase, which may lead to a decrease in thermal insulation. In addition, the formability and strength of the thermal insulation may deteriorate.

[0106] (Inorganic fiber content)

[0107] In the present embodiment, when the heat insulating material 1 contains inorganic fibers, the content of the inorganic fibers is preferably 3% by mass or more and 15% by mass or less relative to the total mass of the heat insulating material.

[0108] In addition, the content of inorganic fibers is more preferably 5% by mass or more and 10% by mass or less relative to the total mass of the thermal insulation member. By setting such a content, the shape retention, compression resistance, wind pressure resistance, and inorganic particle retention capacity of the inorganic fibers are balanced. In addition, by appropriately controlling the content of inorganic fibers, organic fibers and inorganic fibers are entangled with each other to form a three-dimensional network, thereby further improving the effect of retaining inorganic particles and other compounding materials described later.

[0109] (Non-melting fiber)

[0110] The heat insulating material 1 may contain infusible fibers in addition to the first organic fibers 3, the inorganic fibers 16, and the second organic fibers 4. Examples of infusible fibers include fibers obtained by infusible treatment of thermoplastic resins such as polyacrylonitrile, cellulose, and asphalt. Infusible fibers refer to fibers obtained by infusible treatment, for example, and infusible treatment includes a method of crosslinking by irradiation with radiation, electron beams, etc., a method of exposing to high temperature in oxygen and water vapor and infusible by the action of oxygen, etc.

[0111] (Carbon content)

[0112] The carbon content of the infusible fiber is preferably 55% to 95% by mass. If the carbon content is 55% by mass or more, the weight loss caused by thermal decomposition is already in progress, so the shrinkage caused by thermal decomposition is small, and in the case of thermal runaway, even if directly exposed to flames, it can maintain its original shape and maintain thermal insulation. If the carbon content is 95% by mass or less, the components other than carbon are separated and changed into a structure with only carbon, so an endothermic reaction occurs, so the time for heat to reach the back of the fireproof structure can be delayed.

[0113] The lower limit of the carbon content is preferably 60% by mass or more. The upper limit of the carbon content is preferably 90% by mass or less, and the upper limit of the carbon content is more preferably 85% by mass or less.

[0114] The carbon content can be adjusted by heat treatment. For example, heat treatment in the air or in oxygen at a temperature of 150 to 300°C can further promote infusibility and remove components other than carbon to increase the carbon content. For example, heat treatment at a temperature of 300 to 1000°C can promote the formation of condensed polycyclic aromatic structures and generate decomposition gases to increase the carbon content.

[0115] In addition, the infusible fibers are not limited to those obtained by infusible thermoplastic fibers, and may be inorganic fibers as long as the carbon content is within the above-mentioned range.

[0116] (Fiber shape)

[0117] The infusible fibers are preferably composed of short fibers. The so-called short fibers are not continuous fibers. In continuous fibers, the orientation direction of the fibers is consistent to form a fiber bundle, such as a fabric or a fiber winding. In contrast, by using short fibers, the fibers are oriented in random directions to form a collection (mat, felt, papermaking body). In addition, the conductive path of the thermal insulation using short fibers is short, so even if the fibers are carbonized or the carbonization is accompanied by thermal runaway, the conductivity can be reduced. In addition, the fibers are randomly oriented, and the fibers are easily in point contact with each other, which can reduce heat conduction.

[0118] When manufacturing a thermal insulation component containing infusible fibers, it is preferred to use ground fibers or chopped fibers (fiber length of about 0.01 mm to 10 mm) of the infusible fibers. In addition, the fiber diameter of the infusible fibers is preferably 1 μm to 30 μm. When the fiber diameter of the infusible fibers is 1 μm or more, even if exposed to high temperatures, the speed of air oxidation and sublimation can be suppressed, and the fireproof effect can be maintained for a long time. On the other hand, when the fiber diameter of the infusible fibers is 30 μm or less, even if exposed to high temperatures and carbonized, a certain degree of softness can be maintained, and even if deformation or impact occurs, it is not easy to be damaged.

[0119] <Inorganic particles>

[0120] In order to obtain the desired thermal insulation, the thermal insulation member 1 in the protective cover 10 of the present embodiment preferably includes inorganic particles 6. As inorganic particles, a single inorganic particle can be used, or two or more inorganic particles can be used in combination. As the type of inorganic particles, from the viewpoint of thermal insulation effect, it is preferred to use particles composed of at least one inorganic material selected from oxide particles, carbide particles, nitride particles and inorganic hydrate particles, and oxide particles are more preferably used. In addition, there is no particular limitation on the shape, and it is preferred to include at least one selected from nanoparticles, hollow particles and porous particles. Specifically, inorganic hollow spheres such as silica nanoparticles, metal oxide particles, microporous particles, hollow silica particles, particles composed of thermally expandable inorganic materials, particles composed of water-containing porous bodies, etc. can also be used.

[0121] When the average secondary particle size of the inorganic particles is 0.01 μm or more, it is easy to obtain and the increase in manufacturing costs can be suppressed. In addition, when the average secondary particle size of the inorganic particles is 200 μm or less, the desired heat insulation effect can be obtained. Therefore, the average secondary particle size of the inorganic particles is preferably 0.01 μm or more and 200 μm or less, and more preferably 0.05 μm or more and 100 μm or less.

[0122] In addition, when two or more inorganic particles with different heat insulation effects are used in combination, the heat generating body can be cooled in multiple stages, and heat absorption can be exhibited in a wider temperature range. Specifically, it is preferred to mix large-diameter particles and small-diameter particles. For example, when nanoparticles are used as a kind of inorganic particles, it is preferred to include inorganic particles consisting of metal oxides as another inorganic particle. Hereinafter, the inorganic particles with small diameter are used as the first inorganic particles, and the inorganic particles with large diameter are used as the second inorganic particles, and the inorganic particles are described in more detail.

[0123] <First Inorganic Particles>

[0124] (Oxide particles)

[0125] When oxide particles are used as the first inorganic particles, radiative heat transfer can be suppressed, especially in high temperature areas such as abnormal heating. As oxide particles, at least one particle selected from silica, titania, zirconium oxide, zircon, barium titanate, zinc oxide and aluminum oxide can be used. That is, among the above-mentioned oxide particles that can be used as inorganic particles, only one type can be used, or two or more oxide particles can be used. In particular, silica is a component with high heat insulation, and titania is a component with a high refractive index compared to other metal oxides. It has a high effect of diffusely reflecting light and shielding radiant heat in high temperature areas above 500°C, so it is most preferred to use silica and titania as oxide particles.

[0126] In addition, oxide particles have a high refractive index and a strong effect of diffusely reflecting light, so the particle size of oxide particles may affect the effect of reflecting radiant heat. Therefore, when the average primary particle size of oxide particles is limited to a predetermined range, higher heat insulation can be obtained.

[0127] (Average primary particle size of oxide particles: 0.001 μm or more and 50 μm or less)

[0128] When the average primary particle size of the oxide particles is 0.001 μm or more, the particles are sufficiently larger than the wavelength of light that contributes to heating, so that the light is efficiently diffusely reflected. Therefore, in the high temperature region of 500°C or more, the radiation heat transfer of heat in the protective cover is suppressed, and the heat insulation can be further improved. On the other hand, when the average primary particle size of the oxide particles is 50 μm or less, even if compressed, the number of contact points between particles does not increase, and it is difficult to form a path for conductive heat transfer. Therefore, the influence on the heat insulation in the normal temperature region where conductive heat transfer is dominant can be reduced.

[0129] In the present invention, the average primary particle size can be determined by observing the particles with a microscope, comparing with a standard scale, and taking the average value of any 10 particles.

[0130] (Nanoparticles)

[0131] In the present invention, nanoparticles refer to nano-scale particles with an average primary particle size of less than 1 μm in a spherical or nearly spherical shape. Nanoparticles have low density, so they inhibit conductive heat transfer. If nanoparticles are used as the first inorganic particles, finer voids are dispersed, so that excellent thermal insulation that inhibits convective heat transfer can be obtained. Therefore, when a battery is used in a normal temperature range, nanoparticles are preferably used from the perspective of being able to inhibit heat conduction between adjacent nanoparticles.

[0132] Furthermore, if nanoparticles with a small average primary particle size are used as oxide particles, even when the thermal insulator is compressed due to the expansion of the battery cell accompanying thermal runaway and the internal density increases, the increase in the conductive heat transfer of the thermal insulator can be suppressed. The reason for this is believed to be that nanoparticles are easily repelled by static electricity to form fine gaps between particles, and the volume density is low, so the particles are filled in a manner that has a cushioning effect.

[0133] In addition, when nanoparticles are used as the first inorganic particles, the material is not particularly limited as long as it meets the above definition of nanoparticles. For example, silicon dioxide nanoparticles are a material with high heat insulation properties, and the contact points between the particles are small, so the heat conducted by the silicon dioxide nanoparticles becomes smaller than when using silicon dioxide particles with large particle sizes. In addition, the volume density of silicon dioxide nanoparticles usually obtained is 0.1 (g / cm3 ), so even if a large compressive stress is applied to the thermal insulation, the size (area) and number of the contact points between the silica nanoparticles will not increase significantly, and the thermal insulation can be maintained. Therefore, as nanoparticles, silica nanoparticles are preferably used. As silica nanoparticles, wet silica, dry silica, and aerogel can be cited, and the silica nanoparticles that are particularly preferred in this embodiment are described below.

[0134] (Average primary particle size of nanoparticles: 1 nm or more and 100 nm or less)

[0135] When the average primary particle size of the nanoparticles is limited to a predetermined range, higher heat insulation properties can be obtained.

[0136] That is, when the average primary particle size of the nanoparticles is set to be greater than 1 nm and less than 100 nm, especially in a temperature range below 500° C., it is possible to suppress the convection heat transfer and conduction heat transfer of heat in the thermal insulation material, and the thermal insulation performance can be further improved. In addition, even when compressive stress is applied, the gaps remaining between the nanoparticles and the contact points between a large number of particles can suppress the conduction heat transfer, and the thermal insulation performance of the thermal insulation material can be maintained.

[0137] In addition, the average primary particle size of the nanoparticles is more preferably 2 nm or more, and further 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 further preferably 10 nm or less.

[0138] (Inorganic hydrate particles)

[0139] When the inorganic hydrate particles are exposed to heat from the heating element and reach a temperature above the thermal decomposition start temperature, they undergo thermal decomposition, releasing their own crystal water to lower the temperature of the heating element and its surroundings, demonstrating the so-called "endothermic effect." In addition, after releasing the crystal water, they become porous and exhibit a heat-insulating effect through countless air pores.

[0140] 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), etc.

[0141] For example, aluminum hydroxide has about 35% of crystal water, and as shown in the following formula, it undergoes thermal decomposition to release crystal water, exhibiting an endothermic effect. Moreover, after releasing the crystal water, it becomes alumina (Al2O3) as a porous body, which functions as a heat insulator.

[0142] 2Al(OH)3→Al2O3+3H2O

[0143] In a battery cell that has thermal runaway, the temperature rises rapidly to over 200° C. and continues to rise to around 700° C. Therefore, the inorganic particles contained in the thermal insulator 1 are preferably composed of inorganic hydrates having a thermal decomposition starting temperature of 200° C. or higher.

[0144] Regarding the thermal decomposition starting temperatures of the inorganic hydrates listed above, aluminum hydroxide is about 200°C, magnesium hydroxide is about 330°C, calcium hydroxide is about 580°C, zinc hydroxide is about 200°C, iron hydroxide is about 350°C, manganese hydroxide is about 300°C, zirconium hydroxide is about 300°C, and gallium hydroxide is about 300°C. They all roughly overlap with the temperature range of the rapid temperature rise of the battery cell that has thermal runaway, and can effectively suppress the temperature rise. Therefore, they can be said to be preferred inorganic hydrates.

[0145] (Average secondary particle size of inorganic hydrate particles: 0.01 μm or more and 200 μm or less)

[0146] In addition, when inorganic hydrate particles are used as the first inorganic particles, if the average particle size is too large, it takes a certain amount of time for the first inorganic particles (inorganic hydrate) located near the center of the thermal insulation material 1 to reach their thermal decomposition temperature, so that the first inorganic particles near the center of the thermal insulation material 1 may not 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, and more preferably 0.05 μm or more and 100 μm or less.

[0147] (Particles composed of heat-expandable inorganic material)

[0148] Examples of the thermally expandable inorganic material include vermiculite, bentonite, mica, and perlite.

[0149] (Particles composed of a porous body containing water)

[0150] Specific examples of the hydrous porous body include zeolite, kaolinite, montmorillonite, acid clay, diatomaceous earth, wet silica, dry silica, aerogel, mica, vermiculite and the like.

[0151] (Inorganic hollow sphere)

[0152] The thermal insulation member 1 used in the present invention may contain inorganic hollow spheres as the first inorganic particles.

[0153] When the inorganic hollow spheres are included, convection heat transfer or conductive heat transfer of heat in the thermal insulation material 1 can be suppressed in a temperature range lower than 500° C., and the thermal insulation property of the thermal insulation material 1 can be further improved.

[0154] As the inorganic hollow balloon, at least one selected from the group consisting of white sand balloon, silica balloon, fly ash balloon, barite balloon, and glass balloon can be used.

[0155] (Content of inorganic hollow spheres: 60% by mass or less relative to the total mass of the thermal insulation material)

[0156] The content of the inorganic hollow spheres is preferably 60% by mass or less based on the total mass of the thermal insulation material.

[0157] (Average particle size of inorganic hollow spheres: 1 μm or more and 100 μm or less)

[0158] The average particle size of the inorganic hollow spheres is preferably 1 μm or more and 100 μm or less.

[0159] <Second Inorganic Particles>

[0160] When two kinds of inorganic particles are contained in the thermal insulation member 1, the second inorganic particles are not particularly limited as long as they are different from the first inorganic particles in material, particle size, etc. As the second inorganic particles, inorganic hollow spheres such as oxide particles, carbide particles, nitride particles, inorganic hydrate particles, silicon dioxide nanoparticles, metal oxide particles, microporous particles or hollow silicon dioxide particles, particles composed of thermally expandable inorganic materials, particles composed of water-containing porous bodies, etc. can be used, and their details are as described above.

[0161] In addition, the conductive heat transfer of nanoparticles is extremely small, and even when compressive stress is applied to the thermal insulation, it is possible to maintain excellent thermal insulation. In addition, metal oxide particles such as titanium dioxide are highly effective in blocking radiant heat. Furthermore, if large-diameter inorganic particles and small-diameter inorganic particles are used, the small-diameter inorganic particles will enter the gaps between the large-diameter inorganic particles, thereby forming a denser structure, which can improve the thermal insulation effect. Therefore, when, for example, nanoparticles are used as the above-mentioned first inorganic particles, it is preferred that the thermal insulation further contain particles composed of metal oxides having a diameter greater than the first inorganic particles as second inorganic particles.

[0162] Examples of the metal oxide include silicon oxide, titanium oxide, aluminum oxide, barium titanate, zinc oxide, zircon, zirconium oxide, etc. In particular, titanium oxide (titanium dioxide) is a component having a higher refractive index than other metal oxides, and has a high effect of diffusely reflecting light and shielding radiant heat in a high temperature range of 500° C. or higher, so titanium dioxide is most preferably used.

[0163] When at least one particle selected from silica nanoparticles and silica aerogels is used as the first inorganic particle and at least one particle selected from titanium dioxide, zircon, zirconium oxide, silicon carbide, zinc oxide and aluminum oxide is used as the second inorganic particle, in order to obtain excellent thermal insulation performance within a temperature range of 90° C. or less, the first inorganic particle is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more relative to the total mass of the inorganic particles. In addition, the first inorganic particle is preferably 95% by mass or less, more preferably 90% by mass or less, and further preferably 80% by mass or less relative to the total mass of the inorganic particles.

[0164] On the other hand, in order to obtain excellent thermal insulation performance in a temperature range exceeding 90° C., the second inorganic particles are preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 20% by mass or more relative to the total mass of the inorganic particles. In addition, the second inorganic particles are preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less relative to the total mass of the inorganic particles.

[0165] (Average primary particle size of the second inorganic particles)

[0166] When the thermal insulation material contains second inorganic particles composed of metal oxide, if the average primary particle size of the second inorganic particles is 1 μm or more and 50 μm or less, radiant heat transfer can be effectively suppressed in a high temperature region of 500° C. or more. The average primary particle size of the second inorganic particles is more preferably 5 μm or more and 30 μm or less, and most preferably 10 μm or less.

[0167] (Content of Inorganic Particles)

[0168] In the present embodiment, if the total content of the inorganic particles in the thermal insulation material 1 is appropriately controlled, the thermal insulation properties of the thermal insulation material 1 can be sufficiently ensured.

[0169] The total content of inorganic particles is preferably 60% by mass or more, and more preferably 70% by mass or more, relative to the total mass of the thermal insulation member. In addition, when the total content of inorganic particles is too much, the content of organic fibers will be relatively reduced. Therefore, in order to fully obtain the reinforcement effect of the skeleton and the retention effect of the inorganic particles, the total content of inorganic particles is preferably 95% by mass or less, and more preferably 90% by mass or less, relative to the total mass of the thermal insulation member.

[0170] The content of the inorganic particles in the thermal insulation material can be calculated, for example, by heating the thermal insulation material at 800° C. to decompose the organic components and then measuring the mass of the remaining components.

[0171] <Organic particles>

[0172] The heat insulating material 1 in the protective cover 10 of the present embodiment may contain organic particles. As the organic particles, hollow polystyrene particles or the like can be used.

[0173] <Other matching materials>

[0174] (resin adhesive)

[0175] The materials of the heat insulating material 1 in this embodiment may be bonded together by a resin adhesive. As the resin adhesive, for example, a resin adhesive containing at least one selected from styrene-butadiene resin, acrylic resin, silicone-acrylic resin, and styrene resin can be used.

[0176] The glass transition temperature of the resin binder is not particularly specified, but is preferably -10°C or higher. In addition, when the glass transition temperature of the resin binder is room temperature or higher, when the heat insulating material having the resin binder is used at room temperature, the strength of the heat insulating material can be further improved. Therefore, the glass transition temperature of the resin binder is, for example, more preferably 20°C or higher, more preferably 30°C or higher, further preferably 50°C or higher, and particularly preferably 60°C or higher.

[0177] The content of the resin binder is preferably 0.5% by mass or more, more preferably 1% by mass or more, and is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total mass of the thermal insulation material.

[0178] (Hot-melt powder)

[0179] In addition to the above-mentioned various materials, hot-melt powder may be contained in the mixture when manufacturing the thermal insulation member 1. By adding hot-melt powder to the material mixture of the thermal insulation member 1 and heating it, the hot-melt powder melts and solidifies while containing the surrounding inorganic particles when cooled. Therefore, it is possible to further suppress the inorganic particles from falling off from the thermal insulation member.

[0180] As the hot-melt powder, there are hot-melt powders having various melting points, but it is sufficient to select a hot-melt powder having an appropriate melting point. As the component constituting the hot-melt powder, there are polyethylene, polyester, polyamide, ethylene vinyl acetate, etc.

[0181] (Content of hot melt powder)

[0182] When the heat insulating material contains hot melt powder, even a small amount of hot melt powder can suppress powder loss. Therefore, the content of hot melt powder is preferably 0.5% by mass or more, more preferably 1% by mass or more relative to the total mass of the material constituting the heat insulating material.

[0183] On the other hand, if the content of hot-melt powder is increased, the content of inorganic particles, etc. will be relatively reduced. Therefore, in order to obtain the desired thermal insulation performance, the content of hot-melt powder is preferably less than 5 mass%, and more preferably less than 4 mass% relative to the total mass of materials constituting the thermal insulation member.

[0184] In addition, the heat insulating material 1 in the protective cover 10 of the present embodiment may contain other binding materials, colorants, etc. as needed. These are useful for the purpose of reinforcing the heat insulating material 1, improving the formability, etc., and are preferably less than 10% by weight in total relative to the total weight of the heat insulating material.

[0185] In the present invention, the manufacturing method of the heat insulating material 1 may be a wet method or a dry method which are commonly used. As for the materials used in the manufacturing process, it is sufficient to select a material suitable for the manufacturing method from the materials listed above according to the required properties.

[0186] [Inorganic fiber layer]

[0187] The inorganic fiber layer 7 shown in the third embodiment is obtained by processing inorganic fibers into a layered state, for example, and the inorganic fibers used are not particularly limited. For example, the inorganic fibers described in the above-mentioned thermal insulation member 1 may also be used. Among them, silica fibers, alumina fibers, glass fibers, metal fibers, etc. are preferably used in view of low price, excellent handling properties, high heat resistance, etc.

[0188] In addition, there are no restrictions on the shape of the inorganic fibers, such as the fiber diameter, but in consideration of preventing collision of scattered matter during thermal runaway, the inorganic fibers preferably have a small mesh size.

[0189] [Adhesive]

[0190] When the heat insulating member 1 is bonded to the organic film 2, the inorganic fiber layer 7, and the organic film 12 by an adhesive, the adhesive preferably contains an organic material. The adhesive is placed on one side of the components to be bonded, and the other component is placed on the adhesive, and then, for example, the components are heated or pressurized, so that the two components can be bonded. In addition, the content of the organic material in the adhesive is preferably 80% by mass or more relative to the total mass of the adhesive.

[0191] As organic material, there is no particular limitation, and synthetic rubber, polyolefin organic material, polyamide organic material, polyurethane organic material etc. can be cited. In such organic material, preferably at least one of polyolefin organic material and polyamide organic material is included. As the organic material contained in the adhesive, when particularly using polyolefin organic material, the cost of the adhesive can be reduced. In addition, as the organic material contained in the adhesive, when using polyamide organic material, the bonding strength can be improved. Therefore, as long as the material of the adhesive layer is selected according to the required characteristics.

[0192] In addition, as polyolefin organic materials, specifically, polyethylene and polypropylene can be cited. These materials have properties such as flexibility, shock absorption, softness, low rigidity, easy deformation, and the ability to be stretched into a film. Therefore, polyethylene and polypropylene can be suitably used as materials for adhesives.

[0193] [Manufacturing method of protective cover]

[0194] Hereinafter, a method for manufacturing the protective cover 10 according to the first embodiment will be described in order of steps.

[0195] <Thermal insulation material production process>

[0196] First, a thermal insulation material including first organic fibers 3, second organic fibers 4, and inorganic particles 6 is processed into a sheet. At this time, the thermal insulation material is produced in such a manner that the first organic fibers 3 protrude from at least the first surface of a pair of opposing main surfaces of the thermal insulation material, namely, the first surface and the second surface. As a method for producing a sheet-like thermal insulation material such as the above from the thermal insulation material, a dry method or a wet papermaking method can be used. The dry method and the wet papermaking method are described below.

[0197] (Dry method)

[0198] First, a thermal insulation material containing a first organic fiber 3, a second organic fiber 4, and inorganic particles 6 is put into a mixer such as a V-type mixer in a prescribed ratio to prepare a mixture. As the fiber contained in the thermal insulation material, only the inorganic fiber 16 described in the second embodiment can be used, or the inorganic fiber 16 can be used together with the first organic fiber 3 and the second organic fiber 4. In the case of manufacturing the thermal insulation 1 by a dry method, no solvent such as water is added to the mixture. However, in the case of using a water-soluble organic fiber as the second organic fiber 4, in order to improve the formability of the thermal insulation 1 and the retention of the particles, a small amount of water or other solvents can also be added within the scope of the dry method. For example, by adding a small amount of solvent such as water to the mixture, the effect of further suppressing the scattering of inorganic particles during manufacturing can also be obtained. In addition, by making it contain moisture from the outside after molding, the effect of using water-soluble organic fibers can also be obtained.

[0199] Then, the obtained mixture is put into a predetermined mold, and the obtained molded body is heated by applying pressure using a press machine, etc. Then, the heated mixture is cooled to obtain the heat insulating material 1 processed into a sheet shape.

[0200] In addition, there is no particular limitation on the method for producing the thermal insulating material in a manner that the first organic fibers 3 and the second organic fibers 4 protrude from the first surface of the thermal insulating material. For example, when the obtained mixture is put into a predetermined mold, it is passed through a mesh-like sheet having a predetermined mesh size to such an extent that the first organic fibers 3 and the second organic fibers 4 are not completely separated, thereby being arranged above the mixture in a manner that the first organic fibers 3 and the second organic fibers 4 protrude from the upper surface of the mixture. In this way, the thermal insulating material 1 having excellent adhesion to the organic film 2 can be obtained.

[0201] (Wet papermaking method)

[0202] In the wet papermaking method, first, the above-mentioned insulation material is mixed in water and stirred with a stirrer to prepare a mixed solution. Then, the mixed solution is dehydrated by sucking water from the back side of the screen through a sieve for filtering to prepare a wet sheet. Then, the obtained wet sheet is heated and pressurized, thereby obtaining the insulation material 1. In addition, before the heating and pressurizing process, a ventilation drying process in which hot air is blown to the wet sheet to dry the sheet can be implemented, but it is also possible to perform heating and pressurization in a wet state without implementing the ventilation drying process.

[0203] According to the wet papermaking method, when the water of the mixed liquid is sucked from the back side of the screen, the fibers will protrude from the back side of the screen. Therefore, the surface of the screen side when making the thermal insulation member 1 can be set as the first surface 1a, and at least the first surface 1a side can be set as the surface bonded to the organic film 2. In addition, after the mixed liquid is flowed into the screen and the water is sucked to a certain extent, the wet sheet is placed upside down on the screen, and the remaining water is sucked from the back side of the screen to dry it, thereby obtaining the thermal insulation member 1 with fibers protruding from both the first surface 1a and the second surface 1b.

[0204] <Bonding process>

[0205] Next, an organic film 2 is bonded to at least a portion of the surface of the obtained thermal insulation material 1. In this bonding step, the organic film 2 is bonded to at least the first surface 1a side of the thermal insulation material 1. When fibers protrude from both the first surface 1a and the second surface 1b of the thermal insulation material 1, the organic film 2 may be bonded to both surfaces.

[0206] As a method for bonding the heat insulating material 1 and the organic film 2 , an adhesive may be used as described above, or a method of overlapping the two and then heating and pressing them may be used. In this way, the protective cover 10 of the present embodiment can be manufactured.

[0207] According to the method for manufacturing the protective cover of the present embodiment described above, the heat insulating material 1 having excellent adhesion to the organic film 2 can be easily manufactured, and thus the protective cover can be easily manufactured at a low manufacturing cost.

[0208] [Battery module]

[0209] Figure 4 Schematic cross-sectional view of a battery module according to an embodiment of the present invention. Figure 4 As shown, the battery module 100 is a structure in which a plurality of storage batteries 110 are housed in a battery case 120. In addition, the electrode terminals 111 of the storage batteries 110 are connected in series via a bus bar 130.

[0210] The battery case 120 has a top surface 120a, a side wall surface 120b, and a bottom wall surface 120c inside. The protective cover 10 of the first embodiment is attached to the entire top surface 120a of the battery case 120, for example, by means of an adhesive tape. Although not shown in the figure, the protective cover 10 is arranged so that the surface of the protective cover 10 to which the organic film 2 is bonded faces the top surface side of the battery case 120.

[0211] In the battery module 100 thus configured, the protective cover 10 includes the heat insulator 1 and the organic film 2, which have excellent adhesion, and thus can suppress the heat insulator 1 from peeling off from the top surface 120a when the battery 110 is used. Therefore, the heat insulating property of the heat insulator 1 can be maintained, and even if a flame is generated, it can be more reliably prevented from spreading to the outside.

[0212] Moreover, in Figure 4 When the protective cover 10 shown is used as the protective cover 20 of the third embodiment, the inorganic fiber layer 7 can be arranged on the battery 110 side of the heat insulating material 1. In the battery module thus configured, when the battery 110 ruptures due to thermal runaway, the heat insulating material can be protected by the inorganic fiber layer 7, so that the damage of the heat insulating material 1 can be suppressed, and the heat insulating property of the heat insulating material 1 can be further maintained.

[0213] also, Figure 4 The battery module 100 shown has a protective cover 10 installed only on the top surface 120a of the battery housing 120, but the present invention is not limited to this structure. For example, by installing the protective cover 10 on at least one of the top surface 120a, the side wall surface 120b and the bottom wall surface 120c of the battery housing 120, the heat transfer to the outside of the battery housing 120 can be delayed. In addition, if the protective cover 10 is installed on all the surfaces of the top surface 120a, the side wall surface 120b and the bottom wall surface 120c of the battery housing 120, the heat insulation and fire resistance can be further improved. In addition, the protective cover 10 can also be installed between multiple batteries 110.

[0214] Above, various embodiments have been described, but the present invention is certainly not limited to such examples. It is clear to those skilled in the art that various variations or modifications can be thought of within the scope of the application documents, and it should be understood that they will naturally fall within the technical scope of the present invention. In addition, within the scope of not departing from the gist of the utility model, the various constituent elements in the above-mentioned embodiments may also be combined arbitrarily.

[0215] In addition, the present application is based on Japanese patent application (Japanese Patent Application No. 2023-053778) filed on March 29, 2023 and Japanese patent application (Japanese Patent Application No. 2024-018669) filed on February 9, 2024, the contents of which are incorporated herein by reference.

Claims

1. A protective cover, characterized in that: have: A thermal insulation member comprising fibers; and an organic film bonded to at least a portion of the surface of the thermal insulation member, At least a portion of the fibers protrude from a surface of the insulation.

2. The protective cover according to claim 1, characterized in that: The fibers are composed of at least one of first organic fibers and inorganic fibers.

3. The protective cover according to claim 2, characterized in that: The thermal insulation member includes the first organic fibers and second organic fibers different from the first organic fibers.

4. The protective cover according to claim 3, characterized in that: The first organic fiber is polyethylene terephthalate fiber, The second organic fiber is vinylon fiber.

5. The protective cover according to claim 1, characterized in that: The fibers protruding from the surface of the thermal insulator are fused to the organic film.

6. The protective cover according to claim 1, characterized in that: The thermal insulation member has a first surface and a second surface which are opposite to each other. The organic film is disposed on the first surface. An inorganic fiber layer is disposed on the second surface.

7. The protective cover according to claim 6, characterized in that: The thermal insulation material and the inorganic fiber layer are bonded together via an adhesive layer.

8. The protective cover according to claim 6, characterized in that: The thermal insulator and the inorganic fiber layer are covered by the organic film.

9. The protective cover according to claim 6, characterized in that: The inorganic fiber layer is obtained by processing at least one selected from silica fiber, alumina fiber, glass fiber and metal fiber into a layered shape.

10. A battery module, characterized in that: have: The protective cover according to any one of claims 1 to 9; Batteries; and A battery case houses the protective cover and the storage battery.

11. The battery module according to claim 10, characterized in that: The battery housing has a top surface, a side wall surface and a bottom wall surface inside. The organic film in the protective cover is bonded to at least one selected from the top surface, the side wall surface, and the bottom wall surface, and the protective cover is installed in the battery case.

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