Battery unit

Abstract

Provided is a cell characterized in that at least a part of a cell surface is covered by flame resistant fibers, and in that the flame resistant fibers are in direct contact with the cell surface and / or are separated from the cell surface.

Description

Technical Field

[0001] The present invention relates to a battery, a battery unit, and the like.

Background Art

[0002] Power storage devices (sometimes called batteries) such as lithium-ion secondary batteries are widely used in mobile devices, tools, construction machines, automobiles, ships, railways, airplanes, and the like. It is known that batteries have a problem that they may thermally runaway due to damage, internal short circuit, external stress, etc., and cause problems such as ignition, smoke generation, explosion, and deterioration.

[0003] In applications where high-capacity and high-output batteries such as those for vehicles are installed, not only single cells (sometimes called cells) but also assembled batteries containing a plurality of cells (sometimes called cell units, cell stacks, cell assemblies, power storage modules, cell packs, battery packs, etc.) are used. In the case of a cell unit, there is a concern that the above-mentioned problems related to one cell may affect adjacent cells or the outer package of the cell unit. In addition, in the safety standard of lithium-ion secondary batteries, a flame resistance test may be performed. In the flame resistance test, in order to suppress the occurrence of problems, measures are being studied to make it difficult for the heat of a cell in a thermally runaway or abnormally high temperature state to be transmitted to another adjacent cell or the outer package.

[0004] For example, Patent Document 1 describes that a resin molded body containing resin and expandable graphite is attached to a cell together with an adhesive, or is disposed between a plurality of adjacent cells in a cell unit.

[0005] Patent Document 2 describes that a heat-resistant and heat-insulating sheet containing inorganic fibers and clay minerals is laminated on the outermost layer of a cell stack, or is disposed between a plurality of cells in a cell unit.

[0006] Patent Document 3 describes a refractory sheet including a base material containing glass fibers and wet-heat adhesive binder fibers and an inorganic particle layer, and a cell pack including the same is also proposed.

[0007] Patent Document 4 describes manufacturing a heat insulation sheet by impregnating a nonwoven fiber with a basic sol prepared by adding a carbonic acid ester to a water glass composition to form a hydrogel-nonwoven fiber composite, and then drying and removing the liquid contained in the composite, and disposing the manufactured heat insulation sheet between an electronic component accompanied by heat generation and a housing.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0009] Resin molded bodies containing resin, graphite, clay minerals, etc., such as resin sheets, etc., may impair handling properties, productivity, or battery characteristics during incorporation into cells or cell units, cell or cell unit manufacturing, and post-processing processes due to their weight.

[0010] Refractory and heat insulation sheets containing inorganic fibers, such as glass fibers, etc., or inorganic substances, such as glass materials, etc., may melt in cells, cell units, or cell stacks in a state of thermal runaway or abnormal high temperature due to the melt viscosity of the inorganic fibers.

[0011] There is also an idea of physically preventing thermal runaway or thermal ignition of the power storage module by making the fireproof and heat-insulating sheet heavier or thicker. However, since the power storage module is installed in various devices, the laying space is limited and there are dimensional restrictions. With the increase in the capacity of the power storage module, it is also required to achieve both flame resistance and miniaturization.

[0012] In view of the problems of conventional fireproof and heat-insulating materials, an object of the present invention is to provide a cell and a cell unit that have flame prevention properties while ensuring battery characteristics.

Means for Solving the Problems

[0013] The problems described above are solved by the following technical means. <1> A cell, wherein at least a part of the cell surface is covered with a flame-resistant fiber, and the flame-resistant fiber is in direct contact with the cell surface and / or is separated from the cell surface. <2> The cell according to item 1, wherein the entire cell is covered with the flame-resistant fiber. <3> The cell according to item 1, wherein the cell is partially covered with the flame-resistant fiber. <4> The cell according to item 1, wherein the cell is directly covered with the flame-resistant fiber. <5> The cell according to item 1, wherein the cell is indirectly covered with the flame-resistant fiber. <6> The cell according to any one of items 1 to 5, wherein the flame-resistant fiber is disposed inside and / or outside the exterior body of the cell. <7> The cell according to any one of items 1 to 6, wherein the flame-resistant fiber is in the form of a sheet, paper, woven fabric, knitted fabric, non-woven fabric or felt. <8> The flame-resistant fiber is in the form of the felt, and the felt has a thickness of 1 to 10 mm, a basis weight of 100 to 600 g / m 2 and a weight per unit area of 55 to 90 kg / m 3The cell according to item 7, having the bulk density thereof. <9> The cell according to any one of items 1 to 8, wherein the flame-resistant fiber is an organic fiber having flame retardancy, heat resistance, and flame prevention properties. <10> A cell unit, wherein a plurality of assemblies of the cell according to any one of items 1 to 9 are covered with the flame-resistant fiber. <11> A cell unit, characterized in that an assembly of a plurality of cells is covered with a flame-resistant fiber. <12> The cell unit according to item 11, wherein the whole of the assembly or the whole of the cell unit is covered with the flame-resistant fiber. <13> The cell unit according to item 11, wherein the assembly or the cell unit is partially covered with the flame-resistant fiber. <14> The cell unit according to item 11, wherein the assembly or the cell unit is directly covered with the flame-resistant fiber. <15> The cell unit according to item 11, wherein the flame-resistant fiber is sandwiched between the plurality of cells. <16> The cell unit according to item 11, wherein the cell unit includes a plurality of the assemblies, and the flame-resistant fiber is sandwiched between the plurality of assemblies. <17> The cell unit according to any one of items 11 to 16, wherein the assembly or the cell unit is housed in a housing, and the flame-resistant fiber is disposed inside and / or outside the housing. <18> The cell unit according to any one of items 11 to 17, wherein the flame-resistant fiber is in the form of a sheet, paper, woven fabric, knitted fabric, non-woven fabric, or felt. <19> The flame-resistant fiber is in the form of the felt, and the felt has a thickness of 1 to 10 mm, a basis weight of 100 to 600 g / m 2 and a weight per unit area of 55 to 90 kg / m 3The cell unit according to item 18, having the bulk density thereof. <20> The cell unit according to any one of items 11 to 19, wherein the flame-resistant fiber is an organic fiber having flame retardancy, heat resistance, and flame prevention properties. <21> A cell unit in which a single cell or an assembly of a plurality of cells and the cell unit according to any one of items 11 to 20 are covered with the flame-resistant fiber. <22> A cell unit in which the cell according to any one of items 1 to 9 and the cell unit according to any one of items 10 to 20 are covered with the flame-resistant fiber.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a cell and a cell unit having flame prevention properties while ensuring battery characteristics.

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments and can be variously modified.

[0016] <Definition> In this specification, the "cell" refers to a single battery, which is the smallest constituent unit of a battery in which a positive electrode material, a negative electrode material, a separator, a positive electrode terminal, a negative electrode terminal, etc. are housed in an exterior body.

[0017] In this specification, the "assembly" refers to an aggregate of a plurality of cells, and the "cell unit" refers to an assembled battery including the assembly. When housed in a housing, it may be called a power storage module, when a plurality of cells overlap, it may be called a cell stack, and when a plurality of power storage modules are housed in a housing, it may be called a battery pack. Inside the assembly and the cell unit, in addition to the cell, members such as an electrical connection cable and a lead tab electrically connected to the cell may be included as necessary.

[0018] As used herein, "flame-resistant fiber" refers to a fiber obtained by heat-treating an organic fiber in an oxidizing atmosphere, and may also be referred to as oxidized fiber or infusible fiber. Flame-resistant fibers are obtained, for example, in the flame-resistant step, which is the first or upstream step in the carbon fiber manufacturing process.

[0019] As used herein, "coating" refers to the situation where at least a part of the surface of an object is covered by another substance, regardless of whether the object and the other substance are in direct contact, and includes the surface of the object being covered entirely, continuously, regularly, irregularly, or periodically.

[0020] As used herein, "secondary flame" refers to a flame that burns from another ignition source around an object to that object, and is also called "induced fire". "Secondary combustion" refers to the object burning due to a secondary flame. "Spread of fire" refers to a fire that occurs with the object as the ignition source and spreads around the object.

[0021] <First Embodiment> In the first embodiment, a cell is provided, and at least a part of the cell surface is covered with flame-resistant fibers, and the flame-resistant fibers are in direct contact with the cell surface and / or are separated from the cell surface. A cell in which at least a part of the cell surface is directly or indirectly covered with flame-resistant fibers not only improves the flame resistance of the cell itself while ensuring battery characteristics such as output characteristics, capacity characteristics, and cycle stability, but also prevents or suppresses secondary flames from ignition sources such as surrounding members, for example, another cell or cell unit in the vicinity, an exterior body, an electrode, an electrolyte or electrolytic solution, an electrode terminal, a cable, a housing or connection terminal of a power storage module, an electronic device, a tool, a vehicle, etc., or the spread of fire from the cell to surrounding members.

[0022] <Second Embodiment> In the second embodiment, a cell unit is provided, characterized in that an assembly of a plurality of cells is covered with a flame-resistant fiber. In the cell unit, the assembly directly or indirectly covered with the flame-resistant fiber not only improves the flame resistance of the cell unit itself while ensuring battery characteristics such as output characteristics, capacity characteristics, and cycle stability, but also prevents or suppresses the spread of flames from a source of fire, such as surrounding members, for example, surrounding cells, another assembly or another cell unit, an exterior body, electrodes, an electrolyte or an electrolytic solution, electrode terminals, cables, a housing or connection terminals of a power storage module, an electronic device, a tool, a vehicle, etc., or the spread of fire from the cell to surrounding members.

[0023] (Cell) The cell includes an exterior body and at least a pair of positive and negative electrodes housed in the exterior body, and may optionally include at least one selected from the group consisting of a positive electrode terminal, a negative electrode terminal, a separator, an electrolyte, and an electrolytic solution.

[0024] Examples of the cell include secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, lithium-sulfur batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, sodium-sulfur batteries, lead-acid batteries, air batteries, all-solid-state batteries, all-resin batteries, etc. Among them, lithium-ion secondary batteries are preferable from the viewpoint of the effects of the present invention.

[0025] From the viewpoint of the effects of the present invention, the cell is as follows (c1) to (c5): (c1) A configuration in which the entire cell is covered with a flame-resistant fiber, for example, the cell is packaged with a molded body of the flame-resistant fiber, or the entire cell exterior body includes the flame-resistant fiber; (c2) A configuration in which the cell is partially covered with a flame-resistant fiber. For example, as a mode in which the flame-resistant fiber covers only a part of the cell, covering only one side of the cell with a molded body of the flame-resistant fiber, sandwiching a molded body of the flame-resistant fiber between a plurality of adjacent cells, covering only the curved portion of the cylindrical exterior body of the cell with a molded body of the flame-resistant fiber, etc. can be mentioned; (c3) A configuration in which the cell is directly covered by a flame-resistant fiber, for example, a mode in which materials involved in the charge and discharge of the cell, such as a positive electrode material, a negative electrode material, a separator, a positive electrode terminal, a negative electrode terminal, and an electrolyte, are in direct contact with the flame-resistant fiber or its molded body; (c4) A configuration in which the cell is indirectly covered by a flame-resistant fiber, for example, a mode in which materials involved in the charge and discharge of the cell are not in direct contact with the flame-resistant fiber or its molded body, including arranging the flame-resistant fiber or its molded body outside the cell enclosure, sandwiching a non-flame-resistant member between the molded body of the flame-resistant fiber and the cell, inserting the flame-resistant fiber or its molded body between a plurality of cells in which the materials involved in charge and discharge are housed in the enclosure, etc.; and (c5) A configuration in which the flame-resistant fiber is arranged inside and / or outside the cell enclosure; It is preferable to have at least one configuration represented by the above.

[0026] The configurations represented by the above (c1) to (c5) may coexist or overlap in a single cell as exemplified.

[0027] (Flame-resistant fiber) In the first or second embodiment, at least a part of the cell surface or at least a part of the assembly is covered by a flame-resistant fiber. The flame-resistant fiber can be arranged on the cell surface or the assembly entirely, partially, continuously, regularly, irregularly, or periodically. Among them, from the viewpoint of efficiently exerting the effects of the present invention, it is preferable that the whole cell or assembly is wrapped by the molded body of the flame-resistant fiber.

[0028] The flame-resistant fiber may be in direct contact with the cell surface or the outer surface of the assembly, or may be arranged away from the cell surface or the assembly as long as it can cover the cell surface or the assembly. Also, another cell, another assembly, a connecting component, an adhesive, or a binder material may exist between the flame-resistant fiber and the covered surface.

[0029] Generally, flame-resistant fibers are non-combustible or non-melting in air and are a type of refractory organic fiber. Flame-resistant fibers may have heat resistance, chemical resistance, flexibility, light weight, soft touch, insulation, etc., if desired.

[0030] From the perspective of preventing afterglow or spread of fire, organic fibers having flame retardancy, heat resistance, and afterglow prevention properties are preferable as flame-resistant fibers. From the perspective of safety, organic fibers having flame retardancy, heat resistance, and chemical resistance are preferable. From the perspective of preventing afterglow or spread of fire and the safety of cells, it is preferable that the limiting oxygen index (LOI) measured according to JIS K7201 is 40 or more, and more preferably within the range of 50 to 60.

[0031] In the case of flame-resistant fibers having light weight, the specific gravity of the flame-resistant fibers is preferably 1.2 to 1.6, more preferably 1.3 to 1.5, and still more preferably 1.4 ± 0.5, based on the density of water.

[0032] When the molded article containing flame-resistant fibers has a soft touch, when the stiffness of the molded article is measured using a cantilever stiffness tester according to JIS L 1096, JIS L 1912, or JIS L 1913, the non-woven fabric or felt is preferably 50 to 150 mm, and more preferably 60 to 120 mm.

[0033] The raw material of the organic fiber is not limited, and examples thereof include thermo-carbonizable polymers that become carbon when fired.

[0034] Examples of the heat carbonizable polymer include acrylic resins such as polyacrylonitrile, cellulose, phenolic resins, PBO resins such as polyphenylene benzobisoxazole (PBO), aromatic polyamide (aramid) resins, epoxy resins, pitch-based resins, etc. These can be used as raw materials in the carbon fiber manufacturing process. By heat-treating the above raw material fibers in an oxidizing atmosphere such as air in the temperature range of 200 to 400 °C, flame-retardant fibers that are oxidized / stabilized are obtained. In the present invention, fibers made of an oxidized / stabilized acrylic resin are particularly preferred.

[0035] From the viewpoint of the functions and effects of the present invention, the flame-retardant fiber preferably contains the flame-retardant structure represented by the following formula (I):

Chemical formula

[0036] The repeating unit of the flame-retardant structure represented by the above formula (I) may be contained in the flame-retardant fiber randomly or in blocks, and may also be contained in the heat carbonizable polymer described above randomly or in blocks. The flame-retardant fiber containing the repeating unit of the flame-retardant structure represented by the above formula (I) preferably has a carbon atom (C) of 60 to 65%, a hydrogen atom (H) of 1 to 5%, a nitrogen atom (N) of 16 to 24%, and an oxygen atom (O) of 10 to 18% as a preferred atomic composition (mol%), and more preferably has a C of 61 to 64%, an H of 2 to 4%, an N of 18 to 22%, and an O of 12 to 16% as a more preferred atomic composition (mol%).

[0037] The flame-retardant fiber having the repeating unit of the flame-retardant structure represented by the above formula (I) is not limited, but can be obtained, for example, by subjecting an acrylic resin such as polyacrylonitrile (PAN) to cyclization and / or oxidation treatment, and further subjecting it to carbonization treatment to have a predetermined atomic composition if necessary.

[0038] From the perspective of wrapping a cell or an assembly with a molded body of the flame-resistant fiber, the flame-resistant fiber is preferably in the form of a sheet, a paper, a fabric, a knitted fabric, a non-woven fabric, or a felt, more preferably in the form of a sheet, a non-woven fabric, or a felt, and still more preferably in the form of a felt. Here, the sheet in the present invention is a fabric coated with silicon. The felt in the present invention is a kind of non-woven fabric, which is formed by entangling and integrating fibers through processes such as needle punching or columnar flow punching (spunlace) for entangling the fibers. The dimensions of the sheet, paper, fabric, knitted fabric, non-woven fabric, or felt made of the flame-resistant fiber can be determined according to the covering area and covering means of the cell or the assembly.

[0039] Fiber structures such as sheets, papers, fabrics, knitted fabrics, non-woven fabrics, or felts made of the flame-resistant fiber can be obtained by processing the aforementioned oxidized / stabilized flame-resistant fiber into the shape of the fiber structure, but can also be obtained by heat-treating the raw material fiber as the fiber structure in advance. According to this method, the entire fiber structure is in contact with the heated air, and the individual fibers forming the fiber structure are flame-resistant, and inevitably the entire fiber structure becomes uniformly flame-resistant.

[0040] From the perspective of the function and effect of the present invention, the sheet made of the flame-resistant fiber preferably has a thickness of 0.6 to 1.2 mm, more preferably has a thickness of 0.7 to 1.1 mm, and / or preferably has a basis weight of 350 to 830 g / m 2 and more preferably has a basis weight of 380 to 800 g / m 2 .

[0041] From the perspective of the function and effect of the present invention, the fabric made of the flame-resistant fiber preferably has a thickness of 0.5 to 1.1 mm, more preferably has a thickness of 0.6 to 1.0 mm, and / or preferably has a basis weight of 200 to 500 g / m 2 and more preferably has a basis weight of 250 to 450 g / m 2 .

[0042] Paper, fabric, knitted fabric, felt, or non-woven fabric made of heat-resistant fibers is preferably silicon-coated by methods such as sputtering, knife coating, rotary screen, etc. from the perspective of spark protection.

[0043] A fabric made of heat-resistant fibers can be obtained, for example, by sheet-forming heat-resistant fibers obtained by oxidizing / stabilizing acrylic fibers at 200 - 400 °C in air, or by weaving heat-resistant fibers and, if desired, silicon-coating them.

[0044] Paper made of heat-resistant fibers preferably has a thickness of 0.1 - 3.0 mm, more preferably 0.1 - 1.5 mm, and / or a basis weight of 10 - 300 g / m 2 and preferably has a basis weight of 10 - 150 g / m 2 and more preferably has a basis weight of 10 - 150 g / m

[0045] Paper made of heat-resistant fibers can be obtained, for example, in a papermaking process including raw material preparation, papermaking, processing, finishing, etc., by papermaking a paper raw material containing heat-resistant fibers obtained by oxidizing / stabilizing acrylic fibers at 200 - 400 °C in air and, if desired, other pulp raw materials, and, if desired, silicon-coating the paper. Alternatively, a paper can be obtained by papermaking a paper raw material containing pre-silicon-coated heat-resistant fibers and, if desired, other pulp raw materials.

[0046] The non-woven fabric made of heat-resistant fibers preferably has a thickness of 0.4 - 0.9 mm, more preferably 0.5 - 0.8 mm, from the perspective of the effects of the present invention.

[0047] The non-woven fabric made of heat-resistant fibers preferably has a basis weight of 30 - 90 g / m 2 and preferably has a basis weight of 40 - 80 g / m 2 and more preferably has a basis weight of 40 - 80 g / m

[0048] The non-woven fabric made of flame-resistant fibers preferably has any combination of the thickness and basis weight described above from the viewpoint of the effects of the present invention. A binder material may be attached to the non-woven fabric made of flame-resistant fibers in order to facilitate the coating of cells or assemblies, and a form-stable resin such as an acrylic resin may also be attached by methods such as dipping, spraying, and coating.

[0049] From the viewpoint of the effects of the present invention, the felt made of flame-resistant fibers preferably has a thickness of 1 to 10 mm, more preferably a thickness of 2 to 8 mm, and even more preferably a thickness of 2 to 6 mm.

[0050] From the viewpoint of the effects of the present invention, the felt made of flame-resistant fibers preferably has a basis weight of 100 to 600 g / m 2 and more preferably has a basis weight of 110 to 550 g / m 2 and even more preferably has a basis weight of 130 to 500 g / m 2

[0051] From the viewpoint of the effects of the present invention, the felt made of flame-resistant fibers preferably has a bulk density of 55 to 90 kg / m 3 more preferably has a bulk density of 58 to 86 kg / m 3 and even more preferably has a bulk density of 60 to 82 kg / m 3

[0052] From the viewpoint of the effects of the present invention, the felt made of flame-resistant fibers preferably has a volume resistivity measured by JIS K 6911 of 10 8 to 10 12 Ω·cm, and more preferably has a volume resistivity of 10 8 to 10 10 Ω·cm.

[0053] From the viewpoint of the effects of the present invention, the felt made of flame-resistant fibers preferably has any combination of the thickness, basis weight, and bulk density described above. ​​

[0054] The non-woven fabric or felt made of flame-resistant fibers can be obtained, for example, by forming flame-resistant fibers obtained by oxidizing acrylic fibers at 200 to 400°C in air into a cloth shape by needle punching or spunlace, or by forming acrylic fibers into a cloth shape by needle punching or spunlace and then oxidizing / stabilizing them at 200 to 400°C in air. At this time, the properties can be appropriately adjusted by appropriately controlling the conditions for oxidizing the fibers, the conditions for entangling the fibers with needles, and the like.

[0055] Specific examples of the molded body of heat-resistant fibers include, but are not limited to, sputter sheets of the "Rastan (registered trademark)" series manufactured by Asahi Kasei Advance Corporation, non-woven fabrics (such as TOP 5150Z) or felts (such as TOP 8150Z) of the "New Rastan (registered trademark)" series manufactured by Asahi Kasei Advance Corporation, and the like.

[0056] The sputter sheet of the "Rastan (registered trademark)" series, or the non-woven fabric or felt of the "New Rastan (registered trademark)" series is preferably formed of flame-resistant fibers having a repeating unit of the flame-resistant structure represented by the above formula (I) from the viewpoint of the effects of the present invention.

[0057] In the case of the sputter sheet of the "Rastan (registered trademark)" series, from the viewpoint of the effects of the present invention, it preferably has a thickness of 0.7 to 1.1 mm, a basis weight of 380 to 800 g / m 2 and / or preferably has a volume resistivity of 10 8 ~10 10 Ω·cm when measured according to JIS K 6911.

[0058] In the case of the non-woven fabric of the "New Rastan (registered trademark)" series, from the viewpoint of the effects of the present invention, it preferably has a thickness of 0.5 to 0.8 mm, a basis weight of 40 to 80 g / m 2 and / or preferably has a volume resistivity of 10 8 ~1010 It preferably has a volume resistivity of Ω·cm.

[0059] In the case of the felt of the "Neulastan (registered trademark)" series, from the viewpoint of the effects of the present invention, it preferably has a thickness of 2 to 6 mm, a basis weight of 130 to 500 g / m 2 and / or preferably has a volume resistivity of 10 8 ~10 10 Ω·cm when measured by JIS K 6911.

[0060] As means for covering the cell or the assembly with the flame-resistant fiber, although not limited, for example, various techniques such as adhesion, connection, fitting, interlocking, spraying, contact electrification, friction electrification, flocking, packaging, inner lining or outer lining of the exterior body or the housing, folding, integral molding, printing, sealing, etc. may be used.

[0061] When using a non-woven fabric or felt made of flame-resistant fiber, the cell or the assembly may be wrapped with the non-woven fabric or felt, the non-woven fabric or felt may be arranged as an inner lining or outer lining of the exterior body or the housing, or the non-woven fabric or felt may be inserted or attached to the cell or the assembly, regardless of the completion of sealing. Since the flame-resistant fiber itself may be insulating, when covering the cell or the assembly with the flame-resistant fiber, terminals, cables or tabs for electrical integration or electrical connection may be exposed.

[0062] (Positive electrode) The positive electrode generally includes a positive electrode current collector and a positive electrode material-containing layer disposed on the positive electrode current collector. The dimensions of the positive electrode current collector and the positive electrode material-containing layer can be determined according to the cell shape. As the positive electrode current collector, a metal material that is difficult to elute during charge and discharge may be used. For example, when the cell is a lithium-ion secondary battery, aluminum foil is preferable.

[0063] The positive electrode material-containing layer can be disposed on one or both sides of the current collector, can be formed as a single layer or multiple layers on the current collector, and / or can be disposed on the entire surface of the current collector or in a pattern shape.

[0064] The positive electrode material is not particularly limited, and examples thereof include lithium-containing composite oxides such as LiCoO2, LiNiO2, spinel-type LiMnO4, olivine-type LiFePO4, and lithium-nickel-manganese-cobalt composite oxides. The positive electrode material-containing layer may contain a binder material and / or a conductive assistant in addition to the positive electrode material.

[0065] (Positive electrode terminal) The positive electrode terminal can be formed to electrically integrate the positive electrode with an external power source. Also, the positive electrode terminal may be made of the same material as the positive electrode current collector, and can be connected to the positive electrode current collector, integrally formed with the positive electrode current collector, or configured as an end portion of the positive electrode current collector. Further, the positive electrode terminal and the lead tab connected to the positive electrode terminal may constitute a positive electrode lead body and can also be connected to the positive electrode current collector.

[0066] (Negative electrode) The negative electrode generally includes a negative electrode current collector and a negative electrode material-containing layer disposed on the negative electrode current collector. The dimensions of the negative electrode current collector and the negative electrode material-containing layer can be determined according to the cell shape. As the negative electrode current collector, a metal material that is difficult to elute during charge and discharge may be used. For example, when the cell is a lithium-ion secondary battery, a copper foil is preferable.

[0067] The negative electrode material-containing layer can be disposed on one or both sides of the current collector, can be formed as a single layer or multiple layers on the current collector, and / or can be disposed on the entire surface of the current collector or in a pattern shape.

[0068] The negative electrode material is not particularly limited, and examples thereof include carbon materials such as graphite, non-graphitizable carbon, graphitizable carbon, and composite carbon bodies; silicon, tin, metallic lithium, and various alloy materials. The negative electrode material-containing layer may contain a binder material and / or a conductive assistant in addition to the negative electrode material.

[0069] (Negative electrode terminal) The negative electrode terminal can be formed to electrically integrate the negative electrode and an external power source. Further, the negative electrode terminal may be made of the same material as the negative electrode current collector, and can be connected to the negative electrode current collector, integrally formed with the negative electrode current collector, or configured as an end portion of the negative electrode current collector. Also, the negative electrode terminal and the lead tab connected to the negative electrode terminal can form a negative electrode lead body and be connected to the negative electrode current collector.

[0070] (Electrolyte, Electrolyte) The electrolyte is not particularly limited, but an electrolyte in which an electrolyte is dissolved in an organic solvent can be used. The electrolyte is preferably non-aqueous (however, excluding the inclusion of water as inevitable impurities). Examples of the organic solvent include carbonate solvents such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, or a mixture thereof. Examples of the electrolyte include lithium salts such as LiClO4, LiBF4, and LiPF6.

[0071] (Separator) From the viewpoint of safety such as preventing short circuit between the positive and negative electrodes and shutdown, it is preferable that the cell is provided with a separator between the positive and negative electrodes. In the first and second embodiments, a separator provided in a known non-aqueous secondary battery may be used, and from the viewpoints of ion permeability and mechanical strength, it is preferable to use an insulating thin film.

[0072] Examples of the separator include woven fabrics, non-woven fabrics, synthetic resin microporous membranes, etc. Among these, synthetic resin microporous membranes are preferable. Alternatively, using a non-woven fabric or felt made of the flame-resistant fibers described above as the separator is also an aspect of the present invention.

[0073] Examples of the synthetic resin microporous membrane include polyolefin-based microporous membranes such as a microporous membrane containing polyethylene or polypropylene as a main component, or a microporous membrane containing both of these polyolefins. Examples of the non-woven fabric include porous membranes made of heat-resistant resins such as glass, ceramic, polyolefin, polyester, polyamide, liquid crystal polyester, and aramid.

[0074] As the separator, one type of microporous membrane may be configured in a single layer or multiple layers, or two or more types of microporous membranes may be laminated. The separator may also be configured in a single layer or multiple layers using a mixed resin material obtained by melt-kneading two or more resin materials.

[0075] (Exterior body) The exterior body houses materials involved in the charge and discharge of the cell, such as a positive electrode material, a negative electrode material, a separator, a positive electrode terminal, a negative electrode terminal, an electrolyte, and an electrolytic solution. When the cell is a lithium-ion battery, the shape of the cell (i.e., the shape of the exterior body) is classified into a cylindrical type, a square type, and a laminate type.

[0076] From the viewpoint of the operation and effect of the present invention, it is preferable that flame-resistant fibers are disposed inside and / or outside the exterior body. Specifically, fiber structures such as sheets, papers, woven fabrics, knitted fabrics, non-woven fabrics, or felts made of the flame-resistant fibers described above can be attached to the exterior body as an inner lining and / or an outer lining of the exterior body. In the case of the inner lining of the exterior body, the fiber structure may be in full or partial direct contact with the materials involved in the charge and discharge of the cell, or may be separated from the materials involved in the charge and discharge of the cell.

[0077] When the cell is of the cylindrical type, a positive electrode material, a negative electrode material, a separator, a positive electrode terminal, a negative electrode terminal, an insulating material, a gas discharge valve, a gasket, a positive electrode cap, etc. can be housed in a cylindrical can. From the viewpoint of passing the thermal runaway test, it is preferable that a fiber structure made of the flame-resistant fibers described above is inserted or attached in full or in part inside and / or outside the peripheral portion such as the cylindrical portion of a cylindrical exterior body such as a cylindrical can.

[0078] When the cell is rectangular, the positive electrode material, negative electrode material, separator, positive electrode terminal, negative electrode terminal, insulating material, gas discharge valve, etc. can be accommodated in a rectangular can. From the viewpoint of heat insulation, in a rectangular exterior body such as a rectangular can, it is preferable that the fiber structure made of the flame-resistant fiber described above is inserted or attached entirely or partially inside and / or outside at least one surface of the rectangular exterior body. And from the viewpoint of explosion protection, as an explosion-proof valve cover, it is preferably arranged to cover the valve on the surface where the valve is formed.

[0079] As long as the cylindrical can or rectangular can has a cylindrical or rectangular shape, it can be formed of known materials, for example, metal materials such as stainless steel (SUS), iron, aluminum, or alloys thereof.

[0080] When the cell is a laminate type, the positive electrode material, negative electrode material, separator, positive electrode terminal, negative electrode terminal, etc. can be accommodated in an exterior film. Examples of the exterior film include an aluminum film laminated with a polyethylene terephthalate film. When the cell is a pouch type, the materials involved in the charge and discharge of the cell can be stored in a pouch formed of the same material as the exterior film. From the viewpoint of explosion protection, it is preferable that the fiber structure made of the flame-resistant fiber described above is arranged inside and / or outside the pouch.

[0081] As a method for sealing the exterior body, in the case of a cylindrical can or rectangular can, methods such as caulking, welding, screwing, or bolting of the can and the lid can be used. In the case of a laminated packaging material, methods such as heat sealing or impulse sealing can be used.

[0082] (Assembly, Cell Unit, Power Storage Module) A plurality of cells can be arranged so as to be electrically in series, parallel, or a combination thereof to form an assembly. By coating the assembly with a flame-resistant fiber, a cell unit according to a second embodiment can be obtained. A single cell, a plurality of cells, a single cell unit, or a combination thereof can be housed in a housing to form a power storage module. Further, a plurality of power storage modules can be housed in a housing to form a cell pack or a battery pack.

[0083] From the viewpoint of the effects of the present invention, the cell unit is as follows (u1) to (u6): (u1) A configuration in which the entire assembly or the entire cell unit is covered with a flame-resistant fiber. For example, a mode in which the entire power storage module is covered with a flame-resistant fiber or a molded body thereof, a mode in which the entire battery pack is covered with a flame-resistant fiber or a molded body thereof, a mode in which the entire housing contains a flame-resistant fiber, a mode in which the entire outer surface of the housing is covered with a flame-resistant fiber or a molded body thereof, etc.; (u2) A configuration in which the assembly or the cell unit is partially covered with a flame-resistant fiber. For example, covering only a part of the housing with a molded body of a flame-resistant fiber, integrally molding a flame-resistant fiber with a part of the housing, sandwiching a flame-resistant fiber or a molded body thereof between a plurality of adjacent cells in one power storage module, sandwiching a flame-resistant fiber or a molded body thereof between a plurality of adjacent modules in one battery pack, covering only the curved portion of a cylindrical housing with a flame-resistant fiber or a molded body thereof, etc.; (u3) A configuration in which the assembly or the cell unit is directly covered with a flame-resistant fiber. For example, a mode in which an assembly of a plurality of cells is in direct contact with a flame-resistant fiber, inserting or attaching a molded body of a flame-resistant fiber as an inner lining of a housing for a power storage module or a battery pack, etc.; (u4) A configuration in which a flame-resistant fiber is sandwiched between a plurality of cells in an assembly. For example, in a power storage module, inserting or attaching a flame-resistant fiber or a molded body thereof between a plurality of cells in which materials involved in charge and discharge are housed in an exterior body; (u5) The cell unit includes a plurality of assemblies, and a heat-resistant fiber is sandwiched between the plurality of assemblies. For example, inserting or attaching a heat-resistant fiber or its molded body between a plurality of power storage modules individually housed in a casing, inserting or attaching a heat-resistant fiber or its molded body between a plurality of battery packs individually housed in a casing, etc.; and (u6) The assembly or the cell unit is housed in a casing, and a heat-resistant fiber is disposed inside and / or outside the casing; It is preferable to have at least one configuration represented by.

[0084] The configurations represented by the above (u1) to (u6) may coexist or overlap in one cell unit as illustrated.

[0085] Optionally, a plurality of cells according to the first embodiment may be used to form an assembly, and the formed assembly may be further coated with a heat-resistant fiber.

[0086] Optionally, the cell unit according to the second embodiment and a cell or an assembly not coated with a heat-resistant fiber may be combined and further coated with a heat-resistant fiber.

[0087] Optionally, one or a plurality of cells according to the first embodiment may be prepared and combined with the cell unit according to the second embodiment and / or a cell or an assembly not coated with a heat-resistant fiber, and further coated with a heat-resistant fiber.

[0088] The assembly or the cell unit can be housed in a casing. The casing may be formed of the same material, shape, and manufacturing method as the exterior body of the cell described above. From the viewpoint of mountability as a power storage module, a cell pack, or a battery pack, a rectangular shape or a cylindrical shape is preferable, and a rectangular shape is more preferable.

[0089] It is preferable that heat-resistant fibers are arranged inside and / or outside the housing from the viewpoints of heat insulation or explosion prevention. Specifically, a fiber structure such as a sheet, paper, woven fabric, knitted fabric, non-woven fabric, or felt made of the heat-resistant fibers described above can be attached to the housing as an inner lining and / or an outer lining of the housing. In the case of the inner lining of the housing, the fiber structure may be in full or partial direct contact with a single-cell or multi-cell assembly, or may be separated from a single-cell or multi-cell assembly. In the case of the outer lining of the housing, the fiber structure can be arranged as an explosion-proof valve cover so as to cover the valve on the housing surface where the valve is formed, can constitute a part of the housing, and / or can be integrally formed with the housing.

[0090] A power storage module, cell pack, or battery pack including the cell according to the first embodiment and / or the cell unit according to the second embodiment can be used in fields requiring fire resistance, heat resistance, flame retardancy, etc. in order to prevent flaming or fire spread in safety tests such as a nail penetration test, and can be mounted on, for example, mobile devices, vehicles, construction machinery, tools, etc.

Claims

1. At least a part of the cell surface is covered by a flame-resistant fiber, and the flame-resistant fiber is in direct contact with the cell surface or is separated from the cell surface. The flame-resistant fiber is in the form of a felt, and the felt has a thickness of 1 to 10 mm, a basis weight of 100 to 600 g / m ２ , and a bulk density of 55 to 90 kg / m ３ , and a cell characterized in that a morphology-stable resin is adhered to its surface.

2. The cell according to claim 1, wherein the entire cell is covered by the flame-resistant fiber.

3. The cell according to claim 1, wherein the cell is partially covered by the flame-resistant fiber.

4. The cell according to claim 1, wherein the cell is directly covered by the flame-resistant fiber.

5. The cell according to claim 1, wherein the cell is indirectly covered by the flame-resistant fiber.

6. The cell according to any one of claims 1 to 5, wherein the flame-resistant fiber is disposed inside and / or outside the exterior of the cell.

7. The cell according to any one of claims 1 to 6, wherein the flame-resistant fiber is an organic fiber having flame retardancy, heat resistance, and flame spread prevention properties.

8. When the stiffness and softness of the felt, which is a molded article containing the flame-resistant fiber, is measured using a cantilever stiffness tester according to JIS L 1096, JIS L 1912, or JIS L 1913, it is 50 to 150 mm. The cell according to any one of claims 1 to 7.

9. A cell unit in which a plurality of assemblies of the cell according to any one of claims 1 to 8 are covered by the flame-resistant fiber.

10. An assembly of a plurality of cells is covered by a flame-resistant fiber. The heat-resistant fiber is in the form of a felt, and the felt has a thickness of 1 to 10 mm, a basis weight of 100 to 600 g / m ２ and a bulk density of 55 to 90 kg / m ３ A cell unit characterized in that a morphology-stabilizing resin is adhered to its surface.

11. The cell unit according to claim 10, wherein the entire assembly or the entire cell unit is covered by the flame-resistant fiber.

12. The cell unit according to claim 10, wherein the assembly or the cell unit is partially covered by the flame-resistant fiber.

13. The cell unit according to claim 10, wherein the assembly or the cell unit is directly covered by the flame-resistant fiber.

14. The cell unit according to claim 10, wherein the flame-resistant fiber is sandwiched between the plurality of cells.

15. The cell unit according to claim 10, wherein the cell unit includes a plurality of the assemblies, and the flame-resistant fiber is sandwiched between the plurality of assemblies.

16. The cell unit according to any one of claims 10 to 15, wherein the assembly or the cell unit is housed in a housing, and the flame-resistant fiber is disposed inside and / or outside the housing.

17. The cell unit according to any one of claims 10 to 16, wherein the flexibility of the felt, which is a molded article containing the flame-resistant fiber, is 50 to 150 mm when measured using a cantilever flexibility tester in accordance with JIS L 1096, JIS L 1912, or JIS L 1913.

18. The cell unit according to any one of claims 10 to 17, wherein the flame-resistant fiber is an organic fiber having flame retardancy, heat resistance, and flame prevention properties.

19. A cell unit in which a single cell or an assembly of a plurality of cells and the cell unit according to any one of claims 10 to 18 are covered with the flame-resistant fiber.

20. A cell unit in which the cell according to any one of claims 1 to 8 and the cell unit according to any one of claims 9 to 19 are covered with the flame-resistant fiber.

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