Battery

Abstract

To provide a battery more excellent in safety.SOLUTION: A cylindrical battery comprises a cylindrical exterior body for housing a cell element, and safety valves which are arranged at both the ends of the exterior body, respectively. The safety valve has a first metallic member, a support part with an opening, which is provided to support the first metallic member at the peripheral edge of the first metallic member, and a first insulation member which connects the first metallic member and the support part together and which includes a thermoplastic resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to batteries, particularly cylindrical batteries.

Background Art

[0002] A battery can extract energy such as chemical changes as electrical energy and is used in various applications. For example, batteries are used in mobile devices such as mobile phones, smartphones, and notebook computers.

[0003] Conventionally, as such a battery, for example, there is the battery described in Patent Document 1. As shown in FIGS. 1 to 3 of Patent Document 1, the metal can of this battery is used as an electrochemical battery cell container, and includes a side wall (cylindrical tube (4)) that defines first and second opening ends, a first metal end cap (positive electrode end gap (1)) disposed at the first opening end of the side wall and having an inner surface and an outer surface, a terminal plate (nickel interface terminal (9)) soldered to the outer surface of the first end cap, and a second metal plate disposed at the second opening end of the side wall.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, the inventor of the present invention has found that there is room for improvement in safety in the above-described battery.

[0006] Therefore, the main object of the present disclosure is to provide a battery with better safety.

Means for Solving the Problems

[0007] Rather than addressing the issue by building on the prior art, the inventor of the present invention attempted to solve the above problems in a new direction. As a result, the inventor arrived at an invention of a battery that achieves the above main objective. Specifically, the inventor of the present invention conducted intensive studies to solve the above problems. In order to sufficiently suppress a rapid increase in the internal pressure of the battery in an abnormally high temperature state, the inventor came up with the present disclosure in which a heat release mechanism is provided at both ends of the battery to sufficiently suppress a rapid increase in the internal pressure of the battery in an abnormally high temperature state, thereby further improving safety. That is, the present disclosure includes the following embodiments.

[0008] To solve the above problems, a battery according to an embodiment of the present disclosure is a cylindrical battery including a cylindrical exterior body that houses a battery element and safety valves disposed at both ends of the exterior body, wherein the safety valve includes a first metal member, a support portion provided to support the first metal member at a periphery of the first metal member and having an opening, and a first insulating member that connects the first metal member and the support portion and includes a thermoplastic resin.

Advantages of the Invention

[0009] A battery according to an embodiment of the present disclosure is more excellent in safety.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Figure 8

MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be specifically described. It should be noted that the applicant provides the following description and examples for those skilled in the art to fully understand the present disclosure, and does not intend to limit the subject matter described in the claims by these. That is, the present disclosure is not particularly limited to the preferred modes described below, etc., and can be implemented with appropriate changes within the scope of its purpose. In addition, for the sake of easy explanation or understanding of the key points, the present invention may be shown separately in embodiments, examples, etc. However, partial substitution and / or combination of the configurations shown in different embodiments, etc. are possible. In the description of such embodiments, duplicate explanations may be omitted for substantially the same matters, and only different points may be explained. In particular, for the same operational effects due to the same configuration, they may not be sequentially mentioned for each embodiment.

[0012] In addition, in the description of this specification, references to directions or orientations are for convenience of description only and are not intended to limit the scope of the present disclosure unless specifically stated otherwise. For example, relative terms such as "outer (or outside, external or outer periphery)", "inner (or inside, internal or inner periphery)", and their derivative terms should be construed as referring to the directions as described or illustrated. Similarly, "above" an element includes not only the case of contacting the upper surface of the element but also the case of not contacting the upper surface of the element. That is, "above" an element includes not only a position above the element, i.e., an upper position via another object on the element or an upper position with a gap, but also a position immediately above the element in contact with the element. Also, "above" does not necessarily mean the upper side in the vertical direction. "Above" merely indicates the relative positional relationship of an element. That is, unless specifically stated otherwise, the invention need not be limited to a specific direction, orientation, form, etc. Also, terms such as "provided", "arranged", and "connected", and their derivative terms are the same. Unless specifically stated otherwise, they are not limited to a direct mode but may also be a mode in which other elements such as intervening objects are interposed.

[0013] All kinds of numerical ranges referred to in this specification are intended to include the numerical values of the lower and upper limits themselves unless specifically described otherwise, such as "less than". That is, for example, taking the numerical range of 700 to 740 °C as an example, it is construed as including the lower limit value of 700 °C and also the upper limit value of 740 °C.

[0014] [Basic Configuration of Battery] The "battery" referred to in this specification includes not only the so-called "secondary battery" but also the "primary battery" that can only be discharged. That is, the "battery" referred to in this specification may be a "secondary battery" capable of repeated charging and discharging, or a "primary battery" that is substantially only discharged. Note that the "secondary battery" is not overly restricted by its name and may include, for example, a "power storage device".

[0015] Hereinafter, for convenience of explanation, the battery according to the present disclosure will be mainly described by taking a secondary battery as an example.

[0016] The secondary battery according to the present disclosure includes a battery assembly (electronic element) composed of an electrode constituent layer including a positive electrode, a negative electrode, and a separator. In the secondary battery according to the present disclosure, the battery assembly may have a wound structure in which the electrode constituent layer is wound in a roll shape (hereinafter, also referred to as a "wound electrode body" or a "wound structure"). FIG. 1 schematically shows an exemplary embodiment of the appearance of the secondary battery 1. FIG. 1 is a side view schematically showing a battery according to an embodiment of the present disclosure. As shown in FIG. 1, a battery assembly (not shown) is housed inside the exterior body 20. The battery assembly has a configuration in which a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode are wound. In the secondary battery 1, such a battery assembly is enclosed in the exterior body 20 together with an electrolyte (for example, a non-aqueous electrolyte).

[0017] (Positive electrode and negative electrode) The positive electrode is composed of at least a positive electrode material layer and a positive electrode current collector. In the positive electrode, the positive electrode material layer is provided on at least one surface of the positive electrode current collector. The positive electrode material layer contains a positive electrode active material as an electrode active material. For example, each of the plurality of positive electrodes in the battery assembly may have the positive electrode material layer provided on both surfaces of the positive electrode current collector, or the positive electrode material layer may be provided only on one surface of the positive electrode current collector.

[0018] The negative electrode is composed of at least a negative electrode material layer and a negative electrode current collector. In the negative electrode, the negative electrode material layer is provided on at least one surface of the negative electrode current collector. The negative electrode material layer contains a negative electrode active material as an electrode active material. For example, each of the plurality of negative electrodes in the battery assembly may have the negative electrode material layer provided on both surfaces of the negative electrode current collector, or the negative electrode material layer may be provided only on one surface of the negative electrode current collector.

[0019] The electrode active materials contained in the positive electrode and the negative electrode, that is, the positive electrode active material and the negative electrode active material respectively, are substances that are directly involved in the transfer of electrons in the secondary battery and are the main substances of the positive and negative electrodes responsible for charge and discharge, that is, the battery reaction. More specifically, ions are brought into the electrolyte due to the "positive electrode active material contained in the positive electrode material layer" and the "negative electrode active material contained in the negative electrode material layer", and such ions move between the positive electrode and the negative electrode to effect the transfer of electrons and perform charge and discharge. The positive electrode material layer and the negative electrode material layer may be layers that can particularly occlude and release lithium ions. That is, the secondary battery according to the present invention may be a non-aqueous electrolyte secondary battery in which lithium ions move between the positive electrode and the negative electrode through a non-aqueous electrolyte to perform charge and discharge of the battery. When lithium ions are involved in charge and discharge, the secondary battery according to the present invention corresponds to a so-called "lithium ion battery" and has layers capable of occluding and releasing lithium ions as the positive electrode and the negative electrode.

[0020] In view of lithium ion batteries, the positive electrode active material may be a substance that contributes to the occlusion and release of lithium ions. That is, the positive electrode layer may contain any one or two or more of positive electrode materials capable of occluding and releasing lithium. From this perspective, the positive electrode active material may be, for example, a lithium-containing compound. The type of lithium-containing compound is not particularly limited, and examples thereof include lithium-containing composite oxides and lithium-containing phosphate compounds. This is because a high energy density is easily obtained.

[0021] The lithium-containing composite oxide is a general term for oxides containing lithium and one or more other elements (elements other than lithium) as constituent elements, and may have any crystal structure such as a layered rock salt type and a spinel type, for example. The lithium-containing phosphate compound is a general term for phosphate compounds containing lithium and one or more other elements as constituent elements, and may have a crystal structure such as an olivine type, for example. The type of the other element is not particularly limited as long as it is any one or more of arbitrary elements. Among them, the other element is preferably any one or more of the elements belonging to Groups 2 to 15 in the long-period type periodic table. More specifically, the other element is, for example, nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), and the like. This is because a high voltage can be easily obtained by these additive elements.

[0022] The lithium-containing composite oxide having a layered rock salt type crystal structure may be, for example, a compound represented by each of the following formulas (1) to (3). Li a Mn (1-b-c) Ni b M11 c O (2-d) F e ···(1) (In formula (1), M11 is at least one of cobalt (Co), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). a to e satisfy 0.8 ≦ a ≦ 1.2, 0 < b < 0.5, 0 ≦ c ≦ 0.5, (b + c) < 1, -0.1 ≦ d ≦ 0.2, and 0 ≦ e ≦ 0.1. However, the composition of lithium varies depending on the charge-discharge state, and a is the value in the fully discharged state.) Li a Ni (1-b) M12 b O (2-c) F d ···(2) (In formula (2), M12 is at least one of cobalt (Co), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). a to d satisfy 0.8 ≦ a ≦ 1.2, 0.005 ≦ b ≦ 0.5, -0.1 ≦ c ≦ 0.2, and 0 ≦ d ≦ 0.1. However, the lithium composition varies depending on the charge-discharge state, and a is the value in the fully discharged state.) Li a Co (1-b) M13 b O (2-c) F d ···(3) (In formula (3), M13 is at least one of nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). a to d satisfy 0.8 ≦ a ≦ 1.2, 0 ≦ b < 0.5, -0.1 ≦ c ≦ 0.2, and 0 ≦ d ≦ 0.1. However, the lithium composition varies depending on the charge-discharge state, and a is the value in the fully discharged state.)

[0023] Specific examples of the lithium-containing composite oxide having a layered rock salt-type crystal structure include LiNiO 2 , LiCoO 2 , LiCo 0.98 Al 0.01 Mg 0.01 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiNi 0.33 Co 0.33 Mn 0.33 O2 , Li 1.2 , Mn 0.52 , Co 0.175 , Ni 0.1 , O 2 and Li 1.15 (Mn 0.65 , Ni 0.22 , Co 0.13 )O 2 etc. can be mentioned. In addition, when a lithium-containing composite oxide having a layered rock salt-type crystal structure contains nickel, cobalt, manganese, and aluminum as constituent elements, the atomic ratio of the nickel is preferably 50 atomic% or more. This is because a high energy density is easily obtained.

[0024] The lithium-containing composite oxide having a spinel-type crystal structure may be, for example, a compound represented by the following formula (4). Li a Mn (2-b) M14 b O c F d ···(4) (In formula (4), M14 is at least one of cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W). a to d satisfy 0.9 ≦ a ≦ 1.1, 0 ≦ b ≦ 0.6, 3.7 ≦ c ≦ 4.1, and 0 ≦ d ≦ 0.1. However, the composition of lithium varies depending on the charge-discharge state, and a is the value in the fully discharged state.) Specific examples of the lithium-containing composite oxide having a spinel-type crystal structure may be LiMn 2 O 4 etc.

[0025] The lithium-containing phosphate compound having an olivine-type crystal structure is, for example, a compound represented by the following formula (5). Lia M15PO 4 ···(5) (In formula (5), M15 is at least one of cobalt (Co), manganese (Mn), iron (Fe), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), niobium (Nb), copper (Cu), zinc (Zn), molybdenum (Mo), calcium (Ca), strontium (Sr), tungsten (W), and zirconium (Zr). a satisfies 0.9 ≦ a ≦ 1.1. However, the lithium composition varies depending on the charge-discharge state, and a is the value in the fully discharged state.) Specific examples of the lithium-containing phosphate compound having an olivine-type crystal structure include LiFePO 4 , LiMnPO 4 , LiFe 0.5 Mn 0.5 PO 4 and LiFe 0.3 Mn 0.7 PO 4 and the like may be used.

[0026] The lithium-containing composite oxide may also be a compound represented by the following formula (6). (Li 2 MnO 3 ) x (LiMnO 2 ) 1-x ···(6) (In formula (6), x satisfies 0 ≦ x ≦ 1. However, the lithium composition varies depending on the charge-discharge state, and x is the value in the fully discharged state.)

[0027] In addition, the positive electrode material may be, for example, any one or two or more of oxides, disulfides, chalcogenides, and conductive polymers. The oxides may be, for example, titanium oxide, vanadium oxide, and manganese dioxide. The disulfides may be, for example, titanium disulfide and molybdenum sulfide. The chalcogenides may be, for example, niobium selenide. The conductive polymers may be, for example, sulfur, polyaniline, and polythiophene. However, the positive electrode material is not particularly limited and may be other materials other than the above.

[0028] The positive electrode material layer may contain a binder. Further, in order to smoothly promote the transfer of electrons that drive the battery reaction, the positive electrode material layer may contain a positive electrode conductive agent. The binder of the positive electrode may contain, for example, any one or two or more of synthetic rubbers and polymer compounds. The synthetic rubbers may be, for example, styrene-butadiene rubber, fluorine-based rubber, and ethylene propylene diene. The polymer compounds may be, for example, polyvinylidene fluoride and polyimide. The positive electrode conductive agent may contain, for example, any one or two or more of carbon materials. This carbon material may be, for example, graphite, carbon black, acetylene black, and ketjen black. However, as long as the positive electrode conductive agent is a material having conductivity, it may be a metal material, a conductive polymer, or the like.

[0029] Similarly, the negative electrode active material of the negative electrode material layer may be a material that contributes to the intercalation and deintercalation of lithium ions. That is, the negative electrode layer may contain any one or two or more of negative electrode materials capable of storing and releasing lithium. From this perspective, the negative electrode active material may be, for example, various carbon materials, metal-based materials, and / or other materials.

[0030] When a carbon material is used as the negative electrode active material, the change in the crystal structure during lithium intercalation and lithium deintercalation is very small, so a high energy density is easily and stably obtained. In addition, since the carbon material also functions as a negative electrode conductive agent, the conductivity of the negative electrode layer is easily improved.

[0031] Specific carbon materials include, for example, graphitizable carbon, non-graphitizable carbon, and / or graphite. More specifically, the carbon material may be, for example, pyrolytic carbons, cokes, glassy carbon fibers, fired organic polymer compounds, activated carbon, and carbon blacks. The cokes may include pitch coke, needle coke, and petroleum coke. The fired organic polymer compound is a substance obtained by firing (carbonizing) a polymer compound such as a phenol resin and a furan resin at an appropriate temperature. In addition, the carbon material may be low-crystalline carbon heat-treated at a temperature of about 1000°C or lower, or may be amorphous carbon. Note that the shape of the carbon material is not particularly limited and may be at least one of fibrous, spherical, granular, and scaly.

[0032] The "metal-based material" used as the negative electrode active material is a general term for materials containing any one or two or more of metal elements and metalloid elements as constituent elements. When a carbon material is used as the negative electrode active material, a high energy density is easily obtained. The metal-based material may be a single substance, an alloy, a compound, two or more of them, or a material containing at least a part of one or two or more of their phases. However, the alloy may include, in addition to materials composed of two or more metal elements, materials containing one or more metal elements and one or more metalloid elements. Further, the alloy may contain a non-metal element. The structure of this metal-based material may be, for example, a solid solution, eutectic (eutectic mixture), intermetallic compound, and a coexistence of two or more of them. Such metal elements and metalloid elements may be any one or two or more of, for example, metal elements and metalloid elements capable of forming an alloy with lithium. Specifically, the metal elements and metalloid elements may be, for example, magnesium (Mg), boron (B), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), bismuth (Bi), cadmium (Cd), silver (Ag), zinc (Zn), hafnium (Hf), zirconium, yttrium (Y), palladium (Pd) and / or platinum (Pt). In a certain preferred embodiment, the metal elements are silicon and tin. This is because these metal elements have excellent ability to occlude and release lithium, and it is easy to obtain a higher energy density. The material containing silicon as a constituent element may be a single substance of silicon, an alloy of silicon, a compound of silicon, two or more selected from them, or a material containing at least a part of one or two or more of their phases. Similarly, the material containing tin as a constituent element may be a single substance of tin, an alloy of tin, a compound of tin, two or more of them, or a material containing at least a part of one or two or more of their phases. The "single substance" described in this specification is only a single substance in a general sense, so the single substance may contain trace amounts of impurities.That is, the purity of the single substance is not necessarily limited to 100%. The silicon alloy may contain, for example, any one or more of tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, and chromium as constituent elements other than silicon. The silicon compound may contain, for example, any one or more of carbon and oxygen as constituent elements other than silicon. Note that the silicon compound may also contain any one or more of the series of elements described for the silicon alloy as constituent elements other than silicon. Specific examples of the silicon alloy and specific examples of the silicon compound include SiB. 4 、SiB 6 、MgSi, Ni 2 Si, TiSi 2 、MoSi 2 、CoSi 2 、NiSi 2 、CaSi 2 、CrSi 2 、Cu 5 Si, FeSi 2 、MnSi 2 、NbSi 2 、TaSi 2 、VSi 2 、WSi 2 、ZnSi 2 、SiC, Si 3 N 4 、Si 2 N 2 O, SiO v (0 < v ≤ 2), and / or LiSiO, etc. can be mentioned. Note that SiO vv in may be 0.2 < v < 1.4. The tin alloy may contain, for example, any one or more of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, and chromium as constituent elements other than tin. The tin compound may contain, for example, any one or more of carbon and oxygen as constituent elements other than tin. Note that the tin compound may contain any one or more of the series of elements described for the tin alloy as constituent elements other than tin. Specific examples of the tin alloy and specific examples of the tin compound include SnO w (0 < w ≦ 2), SnSiO 3 , LiSnO and / or Mg 2Examples include Sn. In particular, a material containing tin as a constituent element may be, for example, a material containing a second constituent element and a third constituent element together with tin as the first constituent element (tin-containing material). The second constituent element may be, for example, any one or more of cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium, zirconium, niobium, molybdenum, silver, indium, cesium (Ce), hafnium (Hf), tantalum, tungsten, bismuth, and silicon. The third constituent element may be, for example, any one or more of boron, carbon, aluminum, and phosphorus. This is because high battery capacity and excellent cycle characteristics are easily obtained by these elements. Among them, the tin-containing material may be a material containing tin, cobalt, and carbon as constituent elements (tin-cobalt-carbon-containing material). This is because high energy density is easily obtained by these materials. In the tin-cobalt-carbon-containing material, at least a part of the carbon as a constituent element may be bonded to a metal element or a metalloid element that is another constituent element. This is because aggregation and crystallization of tin are easily suppressed. Such a tin-cobalt-carbon-containing material is not limited to a material whose constituent elements are only tin, cobalt, and carbon (SnCoC). This tin-cobalt-carbon-containing material may contain, for example, any one or more of silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus, gallium, and bismuth in addition to tin, cobalt, and carbon as constituent elements. In addition to the tin-cobalt-carbon-containing material, a material containing tin, cobalt, iron, and carbon as constituent elements (tin-cobalt-iron-carbon-containing material) may also be used.

[0033] In addition, the negative electrode material may be, for example, any one or more of metal oxides and polymer compounds. The metal oxide may be, for example, iron oxide, ruthenium oxide, and molybdenum oxide. The polymer compound may be, for example, polyacetylene, polyaniline, and polypyrrole.

[0034] The negative electrode material layer may contain a binder. Furthermore, a negative electrode conductive agent may be contained in the negative electrode material layer in order to smoothly promote the transfer of electrons that drive the battery reaction. The binder that can be contained in the negative electrode material layer is not particularly limited, and examples thereof include at least one selected from the group consisting of styrene-butadiene rubber, polyacrylic acid, polyvinylidene fluoride, polyimide-based resins, and polyamide-imide-based resins. The negative electrode conductive agent that can be contained in the negative electrode material layer is not particularly limited, and examples thereof include carbon blacks such as thermal black, furnace black, channel black, ketjen black, and acetylene black, carbon fibers such as graphite, carbon nanotubes, and vapor-grown carbon fibers, metal powders such as copper, nickel, aluminum, and silver, and at least one selected from the group consisting of polyphenylene derivatives and the like. Note that the negative electrode material layer may contain components resulting from a thickening agent component (such as carboxymethyl cellulose) used during battery manufacturing.

[0035] The positive electrode current collector and the negative electrode current collector used for the positive electrode and the negative electrode are members that contribute to collecting or supplying electrons generated in the electrode active material due to the battery reaction. Such an electrode current collector may be a sheet-like metal member. The electrode current collector may be a single layer or may be multilayered. Furthermore, the electrode current collector may have a porous or perforated form. For example, the current collector may be a metal foil, punching metal, a net, or expanded metal. The positive electrode current collector used for the positive electrode may be made of, for example, a metal foil containing at least one selected from the group consisting of aluminum, nickel, and stainless steel. On the other hand, the negative electrode current collector used for the negative electrode may be made of, for example, a metal foil containing at least one selected from the group consisting of copper, aluminum, nickel, and stainless steel.

[0036] (Separator) The separator used for the positive electrode and the negative electrode is a member provided from the viewpoints of preventing short - circuit due to contact between the positive and negative electrodes and retaining the electrolyte. In other words, the separator is a member that isolates the positive electrode from the negative electrode and allows ions (for example, lithium ions) to pass through while preventing short - circuit of the current caused by contact between the two electrodes. For example, the separator may be a porous or microporous insulating member, and may have a film form due to its small thickness.

[0037] The separator may be, for example, any one or two or more of porous membranes such as synthetic resins and / or ceramics, and may also be a laminated film of two or more porous membranes. The synthetic resins used for the separator are, for example, polytetrafluoroethylene, polypropylene, polyethylene, etc. For example, the separator may include a porous membrane (base material layer) and a polymer compound layer provided on one or both sides of the base material layer. Thereby, the adhesion of the separator to the positive electrode is improved, and the adhesion of the separator to the negative electrode can be improved, so that the distortion of the wound electrode body is easily suppressed. The polymer compound layer may include any one or two or more of polymer compounds such as polyvinylidene fluoride. Thereby, it is excellent in physical strength and tends to be electrochemically stable. In addition, the polymer compound layer may include any one or two or more of insulating particles such as inorganic particles. The types of inorganic particles may be, for example, aluminum oxide and / or aluminum nitride. In the present invention, the separator should not be particularly restricted by its name, and may be a solid electrolyte, a gel - like electrolyte, and / or insulating inorganic particles having a similar function.

[0038] (Electrolyte) In the secondary battery according to the present disclosure, a battery assembly composed of an electrode constituent layer including a positive electrode, a negative electrode, and a separator may be enclosed in an exterior body 20 together with an electrolyte. That is, the electrolyte may be a so - called "non - aqueous" electrolyte.

[0039] The electrolyte typically includes a solvent and an electrolyte salt. The electrolyte may further include any one or two or more of other materials such as additives. In a preferred embodiment, the separator is impregnated with the electrolyte, and further the positive electrode and / or the negative electrode may also be impregnated with the electrolyte.

[0040] - Solvent - The solvent may contain any one or two or more of non-aqueous solvents such as organic solvents. The electrolyte containing a non-aqueous solvent can be a so-called non-aqueous electrolyte. The non-aqueous solvent is, for example, a cyclic carbonate, a chain carbonate, a lactone, a chain carboxylic acid ester and / or a nitrile (e.g., mononitrile), etc. Thereby, it becomes easier to obtain more excellent battery capacity, cycle characteristics and / or storage characteristics, etc. The cyclic carbonate may be, for example, ethylene carbonate, propylene carbonate and / or butylene carbonate, etc. The chain carbonate may be, for example, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and / or methyl propyl carbonate, etc. The lactone may be, for example, γ-butyrolactone and / or γ-valerolactone, etc. The chain carboxylic acid ester may be, for example, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate and / or ethyl trimethylacetate, etc. The nitrile may be, for example, acetonitrile, methoxyacetonitrile and / or 3-methoxypropionitrile, etc. In addition, the non-aqueous solvent may be, for example, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, N,N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N,N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate and / or dimethyl sulfoxide, etc. Among them, it is preferable that the non-aqueous solvent contains any one or two or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, etc. This is because it becomes easier to bring about higher battery capacity, more excellent cycle characteristics and / or more excellent storage characteristics, etc. Furthermore, the non-aqueous solvent may be, for example, an unsaturated cyclic carbonate, a halogenated carbonate, a sulfonic acid ester, an acid anhydride, a dicyano compound (dinitrile compound), a diisocyanate compound, a phosphate ester and / or a chain compound having a carbon-carbon triple bond, etc.This makes it easier to improve the chemical stability of the electrolytic solution. The "unsaturated cyclic carbonate" referred to here is a cyclic carbonate having one or more unsaturated bonds (carbon-carbon double bonds or carbon-carbon triple bonds). Examples of this unsaturated cyclic carbonate include vinylene carbonate, vinyl ethylene carbonate, and / or methylene ethylene carbonate. The "halogenated carbonate" is a cyclic or chain carbonate containing one or more halogen elements as constituent elements. When the halogenated carbonate contains two or more halogens as constituent elements, the types of the two or more halogens may be only one type or two or more types. Examples of the cyclic halogenated carbonate include 4-fluoro-1,3-dioxolan-2-one and / or 4,5-difluoro-1,3-dioxolan-2-one. The chain halogenated carbonate may be, for example, fluoromethyl methyl carbonate, bis(fluoromethyl) carbonate, and / or difluoromethyl methyl carbonate. The sulfonic acid ester may be, for example, a monosulfonic acid ester and / or a disulfonic acid ester. The monosulfonic acid ester may be a cyclic monosulfonic acid ester or a chain monosulfonic acid ester. The cyclic monosulfonic acid ester may be a sultone such as 1,3-propane sultone and / or 1,3-propene sultone. The chain monosulfonic acid ester may be, for example, a compound in which the cyclic monosulfonic acid ester is cleaved in the middle. The disulfonic acid ester may be a cyclic disulfonic acid ester or a chain disulfonic acid ester. The acid anhydride may be, for example, a carboxylic acid anhydride, a disulfonic acid anhydride, and / or a carboxylic acid sulfonic acid anhydride. The carboxylic acid anhydride may be, for example, succinic anhydride, glutaric anhydride, and / or maleic anhydride. The disulfonic acid anhydride may be, for example, ethanedisulfonic anhydride and / or propanedisulfonic anhydride. The carboxylic acid sulfonic acid anhydride may be, for example, sulfobenzoic anhydride, sulfopropionic anhydride, and / or sulfobutyric anhydride.The dinitrile compound is, for example, a compound represented by NC-R1-CN (where R1 is either an alkylene group or an arylene group). This dinitrile compound is, for example, succinonitrile (NC-C 2 H 4 -CN), glutaronitrile (NC-C 3 H 6 -CN), adiponitrile (NC-C 4 H 8 -CN) and phthalonitrile (NC-C 6 H 4 -CN), etc. The diisocyanate compound is, for example, a compound represented by OCN-R2-NCO (where R2 is either an alkylene group or an arylene group). This diisocyanate compound is, for example, hexamethylene diisocyanate (OCN-C 6 H 12 -NCO), etc. The phosphate ester may be, for example, trimethyl phosphate and triethyl phosphate, etc. The chain compound having a triple bond between carbons is a chain compound having one or two or more triple bonds between carbons (-C≡C-). This chain compound having a triple bond between carbons is, for example, propynyl methyl carbonate (CH≡C-CH 2 -O-C(=O)-O-CH 3 ), and propynyl methyl sulfonate (CH≡C-CH 2 -O-S(=O) 2 -CH 3 ), etc.

[0041] -Electrolyte salt- The electrolyte salt contained in the electrolyte may contain, for example, any one or two or more of salts such as lithium salts. The electrolyte salt may contain, for example, salts other than lithium salts. Such salts other than lithium may be, for example, salts of light metals other than lithium. The lithium salt is, for example, lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6) Lithium tetraphenylborate (LiB(C 6 H 5 )) 4 ), lithium methanesulfonate (LiCH 3 SO 3 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), lithium tetrachloroaluminate (LiAlCl 4 ), dilithium hexafluorosilicate (Li 2 SiF 6 ), lithium chloride (LiCl) and / or lithium bromide (LiBr), etc. This is because it is easier to obtain better battery capacity, cycle characteristics and / or storage characteristics, etc. Among them, it may be any one or two or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate and lithium hexafluoroarsenate.

[0042] The exterior body 20 used in the secondary battery corresponds to a member that wraps the battery assembly in which the electrode constituent layer including the positive electrode, negative electrode and separator is laminated as the battery exterior body. Such an exterior body 20 can also be referred to as, for example, a "battery can". The exterior body 20 may have, for example, a hollow structure in which one end portion is closed and the other end portion is provided with an opening. The opening may be a through hole formed at one end portion of the exterior body. The structure of the exterior body having such an opening can also be understood as a structure having an open end portion with one end released. A safety valve may be provided at the opening of the exterior body. It is only an example, but a safety valve may be provided at the opening of the exterior body together with a battery lid and a thermal resistance element, etc.

[0043] <First Embodiment: Cylindrical Battery> The first embodiment of the present disclosure relates to a battery (particularly, a cylindrical battery) 1. With reference to FIGS. 1, 2, and 3, the battery 1 will be described. FIG. 2 is an enlarged cross-sectional view of part A in FIG. 1. FIG. 3 is an enlarged cross-sectional view of part B in FIG. 1. In FIGS. 1 to 3, the Z direction is parallel to the cylindrical axial direction (battery axial direction) of the battery. The "cylindrical axial direction of the battery" corresponds to the central axis of the cylindrical outer package 20 in this specification. The "battery axis" corresponds to the rotation axis of the cylindrical battery in this specification. The radial direction refers to the direction perpendicular to the battery axis. Note that in this specification, a cylinder means that the ratio (aspect ratio) of the height to the diameter of the equivalent diameter of the circle at the bottom surface in the cylindrical shape is large (for example, an aspect ratio of 1 or more). Here, the equivalent diameter of the circle at the bottom surface refers to the diameter of a circle having the same area as the area of the bottom surface.

[0044] As shown in FIGS. 1 to 3, the battery 1 according to the first embodiment includes a cylindrical outer package 20 that houses battery elements, and safety valves 10A and 10B disposed at both ends of the outer package 20. The safety valves 10A and 10B include first metal members 11A and 11B, support portions 12A and 12B provided to support the first metal members 11A and 11B at the peripheries of the first metal members 11A and 11B and having openings, and first insulating members that connect the first metal members 11A and 11B to the support portions 12A and 12B and include a thermoplastic resin. Note that in FIGS. 1 to 3, the reference signs of the respective members of the safety valve disposed on the upper side (the forward Z direction side) include "A", and the reference signs of the respective members of the safety valve disposed on the lower side (the reverse Z direction side) include "B".

[0045] [Operating mechanism] The battery 1 according to the first embodiment can provide a battery with excellent safety. The reason is speculated as follows. In the battery 1 according to the first embodiment, the safety valves 10A and 10B have first insulating members 13A and 13B that connect the first metal members 11A and 11B to the support portions 12A and 12B and include a thermoplastic resin. Therefore, the first insulating members 13A and 13B insulate the first metal members 11A and 11B from the support portions 12A and 12B during normal use (in the normal state), preventing communication between the inside and outside of the battery 1. On the other hand, when an abnormality occurs during the use of the battery 1 (in the abnormally high temperature state), the thermoplastic resin contained in the first insulating members 13A and 13B softens due to heat, and a gas discharge path for communicating the inside and outside of the battery 1 is formed in the safety valves 10A and 10B. Therefore, a rapid increase in the internal pressure of the battery 1 due to gas generation inside the battery 1 can be suppressed (hereinafter, such a safety mechanism that operates in this way is also referred to as a "thermal release mechanism"). From the above, the battery 1 according to the first embodiment is more excellent in safety.

[0046] In this specification, the "normal state" means a state in which the pressure (internal pressure) inside the battery 1, that is, the internal pressure of the exterior body 20, is within the normal range and the safety mechanism (the above-described thermal release mechanism and the first metal member cracking mechanism (or "safety cover cracking mechanism") described later) is not operating. Also, the abnormally high temperature state means a state in which gas is abnormally generated inside the battery 1 due to an increase in the temperature inside the battery 1. For example, the "abnormally high temperature state" means a state in which the temperature of the battery 1 is 200°C or higher.

[0047] The battery 1 includes safety valves 10A and 10B and an exterior body 20. Hereinafter, each member will be described.

[0048] (Safety Valve) The safety valves 10A and 10B are arranged at both ends of the cylindrical exterior body 20. The shapes of the safety valves 10A and 10B may be circular, polygonal, or other shapes in a plan view (i.e., when viewed from the Z direction). In this specification, "circular" includes, for example, a perfect circle, an ellipse, and a substantially circular shape. A substantially circular shape is a general term for shapes in which a perfect circle is partially or entirely distorted. "Polygonal" includes, for example, a triangle, a quadrilateral, a pentagon, and a hexagon. "Other shapes" include, for example, shapes other than circular shapes whose contours are formed only by curves, shapes formed by combining two or more polygons, and shapes formed by combining one or more circular shapes and one or more polygons. Such definitions will be the same hereinafter. In the illustrated exemplary embodiment, the outer contour shape of the safety valves 10A and 10B in a plan view is circular.

[0049] The safety valves 10A and 10B include first metal members 11A and 11B, support portions 12A and 12B, and first insulating members 13A and 13B. These member parts will be described in detail below.

[0050] - First Metal Member (Safety Cover)- The first metal members 11A and 11B are supported by the support portions 12A and 12B at their peripheries. The first metal members 11A and 11B are connected to the support portions 12A and 12B via the first insulating members 13A and 13B.

[0051] The first metal members (also referred to as "safety covers") 11A and 11B mainly close both open ends of the exterior body 20.

[0052] The first metal members 11A and 11B are electrically connected to battery elements housed within the exterior body 20 and can serve as external terminals.

[0053] The first metal members 11A and 11B are composed of metal members and have conductivity. For example, the first metal members 11A and 11B may contain at least one metal among metal materials such as aluminum (e.g., aluminum alloys such as A1050, A3203, and A5052), titanium, platinum, and gold.

[0054] The planar shape of the first metal members 11A and 11B, that is, the outer contour shape in a plan view as seen along the battery axis direction (also referred to as the "outer contour shape in plan view") is not particularly limited and may be, for example, circular, polygonal, or other shapes. In the illustrated exemplary embodiment, the outer contour shape of the first metal members 11A and 11B in plan view is circular.

[0055] The first metal members 11A and 11B may be, for example, flat plate-shaped as a whole. That is, the first metal members 11A and 11B may have a form that extends on the same plane.

[0056] A conductive member extending from the battery assembly is electrically connected to the first metal members 11A and 11B. The conductive member may be a conductive member containing metal, and preferably may be a metal member having an elongated shape. For example, the conductive member may be composed of an electrode current collector of the battery assembly, or may be a current collecting lead provided on the battery assembly (particularly, its electrode). When the conductive member is composed of an electrode current collector, the conductive member may be formed from a portion of the electrode current collector where no electrode material is provided. When the conductive member 15 is a current collecting lead, the conductive member is composed of a metal member having a thin-walled form and / or an elongated form and may be connected to the electrode. In the present disclosure, the conductive member that electrically connects the battery assembly and the electrode terminal to each other can also be referred to as a "tab". The conductive member used in the secondary battery preferably has flexibility and may be provided in a bent form and / or a curved form.

[0057] -Support portion- The support portions 12A and 12B are provided to support the first metal members 11A and 11B at the peripheries of the first metal members 11A and 11B and have openings.

[0058] The support portions 12A and 12B are provided at both open ends of the exterior body 20 so as to project from the exterior body 20 toward the battery axis. The support portions 12A and 12B have openings. The support portions 12A and 12B support the first metal members 11A and 11B arranged so as to close the openings.

[0059] The support portions 12A and 12B are connected to the cylindrical exterior body 20 at both open ends thereof. The support portions 12A and 12B may be portions continuous with the exterior body 20. That is, the support portions 12A and 12B and the exterior body 20 may be an integral body. More specifically, the members forming the support portions 12A and 12B may be bent toward the battery axis at the edges (both open ends) of the exterior body 20 and correspond to the portions projecting to the inner peripheral side of the exterior body 20. In one embodiment, the support portions 12A and 12B may correspond to the projecting surfaces formed at the edges of the exterior body 20 by caulking one of the open ends of the exterior body 20.

[0060] Alternatively, the support portions 12A and 12B may be separate members from the exterior body 20 (see FIGS. 1 to 3). That is, the support portions 12A and 12B have a planar outer contour shape corresponding to the planar shape of the edges of the exterior body 20 and may be combined with the edges of the exterior body 20 using a welding method or the like. A through hole is formed in the region surrounded by the support portions 12A and 12B, and the through hole corresponds to the open end of the exterior body 20. The battery 1 including the exterior body 20 having such a structure can have, for example, a structure without a beading portion. In other words, this structure is a structure in which the outer surface of the exterior body 20 is parallel to the battery axis direction.

[0061] The "beading part" refers to the part of the exterior body that tapers toward the battery axis side. In other words, the "beading part" is the part that tapers so as to protrude toward the inside of the exterior body, and can also be referred to as a "constricted part" or a "narrow part". Conventionally, in a battery including an exterior body having a beading part, a support member such as a gasket is disposed in the beading part, and safety valves 10A and 10B are held inside the exterior body via the gasket part. That is, the conventional safety valves 10A and 10B (i.e., the thermal release mechanism) are disposed inside the exterior body having the beading part.

[0062] On the other hand, according to the present disclosure, since the safety valves 10A and 10B can be disposed at both ends of the exterior body 20, the safety valves 10A and 10B can be disposed regardless of the beading part. Therefore, the safety valves 10A and 10B can be disposed not only on the exterior body having the beading part but also on the exterior body not having the beading part. By disposing the safety valves 10A and 10B on the outer side of the battery 1, a larger internal space of the exterior body 20 where the battery assembly can be disposed can be secured as compared with a battery having a beading part. That is, according to the present disclosure, since the safety valves 10A and 10B can be disposed on the exterior body 20 enabling a high energy density, a battery 1 having a high energy density and excellent safety can be obtained.

[0063] The support parts 12A and 12B may be conductive members. For example, the support parts 12A and 12B may be composed of one or more of metal materials such as iron, aluminum, stainless steel, and their alloys. The support parts 12A and 12B may be of the same material as each other, or may be of different materials. On the surface of the support parts 12A and 12B, for example, any one or more of metal materials such as nickel may be plated. When both the support parts 12A and 12B and the exterior body 20 described later are conductive members, the support parts 12A and 12B and the exterior body 20 can be electrically connected.

[0064] -First insulating member- The first insulating members 13A and 13B insulate the first metal members 11A and 11B from the support portions 12A and 12B and are made of a thermoplastic resin. The first insulating members 13A and 13B may be made of a thermoplastic resin.

[0065] The first insulating members 13A and 13B are disposed in a circumferential portion where the first metal members 11A and 11B and the support portions 12A and 12B overlap in the battery axial direction.

[0066] The first insulating members 13A and 13B are interposed between the first metal members 11A and 11B and the support portions 12A and 12B. The first insulating members 13A and 13B electrically insulate the first metal members 11A and 11B from the support portions 12A and 12B.

[0067] Further, the first insulating members 13A and 13B can seal between the first metal members 11A and 11B and the support portions 12A and 12B in a normal state. Therefore, the first insulating members 13A and 13B isolate the inside and the outside of the battery 1. On the other hand, in an abnormally high temperature state, the thermoplastic resin contained in the first insulating members 13A and 13B softens, and (the adhesive force between the first metal members 11A and 11B and the support portions 12A and 12B decreases) a gas discharge path that communicates the inside and the outside of the battery 1 can be formed. Therefore, in an abnormally high temperature state, the gas generated inside the battery 1 is discharged to the outside of the battery 1 through the gas discharge path formed by the safety valves 10A and 10B. Thus, a rapid increase in the internal pressure of the battery 1 is suppressed, and the battery 1 is more excellent in safety.

[0068] From the perspective of further preventing the volatilization of the electrolyte from inside the battery 1 and further preventing the intrusion of moisture from outside the battery 1, in a preferred embodiment, the thermoplastic resin may contain at least one resin selected from the group consisting of super engineering plastics resins and polyolefin resins. Examples of super engineering plastics resins include polyetheretherketone (PEEK), polyamideimide (PAI), polyphenylene sulfide (PPS), polyetherimide (PEI), polyetherketoneketone (PEKK), polyethylene naphthalate (PEN), super engineering plastics polysulfone (PSU), polyethersulfone (PES), polyarylate (PAR), polyamideimide (PAI), polyimide (PI), PBI (polybenzimidazole), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), neoflon (PFA), fluoron, neoflon (ETFE), or polyvinylidene fluoride (PVDF), etc. Examples of polyolefin resins include polyolefin resins such as polyethylene, polypropylene, polymethylpentene, polybutene, ethylene-propylene copolymer, ethylene-α-olefin copolymer, propylene-α-olefin copolymer, etc., and olefin-based copolymer resins such as ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-(meth)acrylic acid (ester) copolymer, ethylene-unsaturated carboxylic acid copolymer metal neutralized product (ionomer), etc. By the thermoplastic resin layer 140 comprising the thermoplastic resin as described above, when the battery is in an abnormally high temperature state, it can preferably soften and be thermally cracked between the support portions 12A, 12B and the safety valves 10A, 10B.

[0069] The melting point of the thermoplastic resin can be 320 °C or higher, 340 °C or higher, 350 °C or higher, or 360 °C or higher. When the melting point is within the above range, thermal cracking occurs more preferably in an abnormally high temperature state, and a battery 1 with better safety can be obtained. In a non-abnormally high temperature state, when emphasis is placed on the thermoplastic resin layer 140 properly adhering and sealing between the safety valves 10A and 10B and the exterior body 20, the melting point of the thermoplastic resin layer 140 can be, for example, 80 °C or higher. Also,

[0070] From the viewpoint of improving the resistance of the first insulating members 13A and 13B to the electrolytic solution, the thermoplastic resin preferably contains a crystalline thermoplastic resin.

[0071] (Exterior body) The exterior body 20 is cylindrical and houses the battery element. The exterior body 20 is connected to the safety valves 10A and 10B at both open ends. The shape of the exterior body 20 is, for example, a cylinder and a polygonal prism. "Cylinder" means that its bottom surface is a cylinder such as a perfect circle (true circle), an ellipse, and a substantially circular shape. "Polygonal prism" means that its bottom surface is a polygonal prism such as a triangle, a quadrilateral, a pentagon, and a hexagon. In the illustrated exemplary embodiment, the shape of the exterior body 20 is a cylinder.

[0072] The exterior body 20 may be a conductive member. For example, the exterior body 20 may be made of one or more of metal materials such as iron, aluminum, stainless steel, and their alloys. The exterior bodies 20 may be of the same material as each other, or may be of different materials. On the surface of the exterior body 20, for example, one or more of metal materials such as nickel may be plated.

[0073] [Method for manufacturing a battery] Taking the manufacturing method of a secondary battery as an example, the manufacturing method of the battery 1 according to the present disclosure will be exemplarily described. The secondary battery according to the present disclosure can be manufactured, for example, by the following procedure.

[0074] When manufacturing the positive electrode, a positive electrode mixture is obtained by mixing a positive electrode active material and, if necessary, a positive electrode binder, a positive electrode conductive agent, etc. Next, a paste-like positive electrode mixture slurry is obtained by dispersing the positive electrode mixture in an organic solvent or the like. Then, the positive electrode mixture slurry is applied to one or both sides of the positive electrode current collector, and the positive electrode mixture slurry is dried to form a positive electrode active material layer. Thereafter, if necessary, the positive electrode active material layer may be compression-molded using a roll press or the like. In such a case, the positive electrode active material layer may be heated, or the compression molding may be repeated a plurality of times. Similarly, the negative electrode can be manufactured. Specifically, after obtaining a negative electrode mixture by mixing a negative electrode active material, a negative positive electrode binder, a negative electrode conductive agent, etc., a paste-like negative electrode mixture slurry is obtained by dispersing the negative electrode mixture in an organic solvent or the like. Next, after applying the negative electrode mixture slurry to one or both sides of the negative electrode current collector, the negative electrode mixture slurry is dried to form a negative electrode active material layer. Thereafter, if necessary, the negative electrode active material layer is compression-molded using a roll press or the like.

[0075] When assembling the secondary battery, a positive electrode lead is connected to the positive electrode current collector using a welding method or the like, and a negative electrode lead is connected to the negative electrode current collector using a welding method or the like. Next, after laminating the positive electrode and the negative electrode via a separator, the positive electrode, the negative electrode, and the separator are wound to form a wound electrode body. Next, a center pin is inserted into the winding space of the wound electrode body. Then, while sandwiching the wound electrode body between a pair of insulating plates, the wound electrode body together with the pair of insulating plates is housed inside the exterior body. In this case, one end of the positive electrode lead is connected to the first metal members 11A, 11B using a welding method or the like, and similarly, one end of the negative electrode lead is connected to the exterior body 20 using a welding method or the like. Next, an electrolytic solution is injected into the interior of the exterior body 20, and the electrolytic solution is impregnated into the wound electrode body. Finally, support portions 12A, 12B are provided on the exterior body 20, and the first metal members 11A, 11B are fixed via the first insulating members 13A, 13B on the support portions 12A, 12B. Thereby, a secondary battery equipped with a heat release mechanism is completed.

[0076] <Second Embodiment: Cylindrical Battery> The second embodiment relates to a cylindrical battery. The cylindrical battery according to the second embodiment is different from the cylindrical battery 1 according to the first embodiment in that, in addition to the heat release mechanism, it further includes a first metal member cracking mechanism. In other words, the cylindrical battery according to the second embodiment mainly further includes a second metal member and a second insulating member. Hereinafter, this different configuration will be mainly described. In the second embodiment, the same reference numerals as those in the first embodiment are used for the same components as in the first embodiment, and thus the description thereof will be omitted in principle. Hereinafter, the cylindrical battery according to the second embodiment will be described with reference to FIGS. 4, 5, and 6. FIG. 4 is a cross-sectional view schematically showing an end portion of the battery according to the second embodiment (in a normal state). FIG. 5 is an exploded perspective view schematically showing an end portion of the battery according to the second embodiment. FIG. 6 is a cross-sectional view schematically showing an end portion of the battery according to the second embodiment of the present disclosure (in an abnormally high temperature state).

[0077] The battery 1a according to the second embodiment In at least one of the two safety valves 10A and 10B disposed at both ends of the cylindrical outer package 20, that is, in the safety valve 10A, A second metal member 14A provided on the inner surface side of the first metal members 11A and 11B and electrically connected to the first metal members 11A and 11B, A second insulating member 15A that connects the peripheries of the first metal members 11A and 11B and the second metal member 14A and contains a thermosetting resin And further includes, The first metal members 11A and 11B have a first groove portion radially inward perpendicular to the battery axis corresponding to the rotation axis of the cylindrical battery with respect to the connection portion between the first metal members 11A and 11B and the periphery of the second metal member 14A. The second metal member 14A has a central portion electrically connected to the first metal members 11A and 11B, a second groove portion, and an outer peripheral portion surrounding the central portion via the second groove portion.

[0078] [Operating mechanism] The cylindrical battery 1a according to the second embodiment is even more excellent in safety. The reason is presumed as follows. The cylindrical battery 1a further includes a second metal member 14A and a second insulating member 15A. The first metal members 11A and 11B have first groove portions on the radially inner side perpendicular to the battery axis corresponding to the rotation axis of the cylindrical battery with respect to the connection portions between the first metal members 11A and 11B and the periphery of the second metal member 14A. The second metal member 14A has a central portion electrically connected to the first metal members 11A and 11B, a second groove portion, and an outer peripheral portion surrounding the central portion via the second groove portion. When an abnormality occurs during the use of the battery 1 (in the case of an abnormally high temperature state), gas is generated inside the battery 1a and the internal pressure increases. Due to the increase in the internal pressure, stress is applied to the second metal member 14A, which is cut at the second groove portion, and the central portion is separated from the outer peripheral portion. As a result, the electrical connection between the second metal member 14A (outer peripheral portion thereof) and the first metal member 11A is interrupted (such a safety mechanism that operates in this way is also referred to as a "first metal member cracking mechanism"). Therefore, in addition to the heat release mechanism, since such a first metal member cracking mechanism operates, the cylindrical battery 1a according to the second embodiment is even more excellent in safety. In this embodiment, an opening is formed by the separation of the central portion of the second metal member 14A from the outer peripheral portion (peripheral edge portion) 142A. Therefore, the formed opening can serve as a path for the gas generated inside the battery 1a to be discharged to the outside of the battery 1a, and thus the heat release mechanism operates more effectively. Here, the central portion includes a protruding portion 141A in the second metal member 14A of FIGS. 4 and 5 and is connected to the inner edge of the outer peripheral portion 142A via the second groove portion 143A.

[0079] The safety valve 10A is provided to a battery terminal (i.e., an external terminal of a positive electrode or a negative electrode), and has a mechanism (a first metal member cracking mechanism) that can mutate in response to an excessive internal pressure of the battery 1a as a safety mechanism. More specifically, the safety valve 10A at least includes, as constituent elements, a first metal member 11A and a second metal member 14A that can be displaced in response to an excessive battery internal pressure, a second insulating member 15A therebetween, a support portion 12A that supports the first metal member 11A, and a first insulating member 13A that connects the first metal member 11A and the support portion 12A. As an exemplary embodiment, the following description will be given by taking, as an example, an embodiment in which the first metal member 11A may correspond to a safety cover and the second metal member 14A may correspond to a stripper disk.

[0080] As shown in FIGS. 4 to 5, the safety valve 10A has a configuration in which the first metal member 11A, the second insulating member 15A, the second metal member 14A, the first insulating member 13A, and the support portion 12A are combined with each other in that order. When viewed along the cylindrical axial direction of the battery 1a, the first metal member 11A is positioned relatively on the outer side of the battery (i.e., the side farther from the battery assembly such as a wound structure), while the second metal member 14A is positioned relatively on the inner side of the battery 1a (i.e., the side closer to the battery assembly such as a wound structure). The second insulating member 15A is interposed between the first metal member 11A and the second metal member 14A.

[0081] The safety valve 10A includes a first metal member 11A, a support portion 12A provided to support the first metal member 11A at the periphery of the first metal member 11A and having an opening, and a first insulating member 13A that connects the first metal member 11A and the support portion 12A and is made of a thermoplastic resin. Further, a second metal member 14A is provided on the inner surface side of the first metal member 11A and is electrically connected to the first metal member 11A, and a second insulating member 15A that connects the peripheries of the first metal member 11A and the second metal member 14A and contains a thermosetting resin. The second metal member 14A is disposed in the opening of the support portion 12A. The second metal member 14A has a protruding portion that is disposed at the center and protrudes outward relative to the battery axis and is electrically connected to the first metal member 11A, and a peripheral portion that is disposed at the periphery of the protruding portion and is connected to the first metal member 11A via the second insulating member 15A.

[0082] Such a safety valve 10A is provided at at least one open end of the exterior body 20. The safety valve 10A may further include a top cover 16A. The top cover 16A may be provided outside the first metal member 11A in the battery axis direction. Hereinafter, each member constituting the safety valve 10A will be described in more detail.

[0083] - First metal member (safety cover)- The first metal member 11A corresponds to a displaceable member that can be deformed and / or cracked in response to the internal pressure of the exterior body 20. As described above, the internal pressure of the exterior body 20 can undesirably increase due to gases such as carbon dioxide generated when the battery 1a is in an abnormally high temperature state. The first metal member 11A may be deformable and / or crackable in response to such an increase in internal pressure. The first metal member 11A can be deformed in the direction outside the battery axis by the gas generated in the abnormally high temperature state.

[0084] The first metal member 11A may have a substantially constant thickness except for a first groove portion 111A provided in the first metal member 11A. The first metal member 11A is substantially circular in plan view.

[0085] - Second metal member (stripper disk)- The second metal member 14A is disposed relatively inside the battery 1a with respect to the first metal member 11A via the second insulating member 15A. The second metal member 14A corresponds to a member that contributes to interrupting the electrical connection between the battery assembly disposed inside the exterior body 20 and the first metal member 11A and / or the top cover 16A.

[0086] The second metal member 14A is disposed in the opening of the support portion 12A. The second metal member 14A is disposed at the center, protrudes relatively outward toward the battery axis, and has a protruding portion 141A that is electrically connected to the first metal member 11A, and an outer peripheral portion 142A that is disposed at the periphery of the protruding portion 141A and is connected to the first metal member 11A via the second insulating member 15A.

[0087] The second metal member 14A is provided with a second groove portion 143A for interrupting the current path in the event of an abnormality in the battery 1a. The second groove portion 143A may be provided concentrically from the center so as to surround, for example, the battery axis. The second groove portion 143A may be in the form of a continuous annular shape surrounding the battery axis, or may be in the form of an intermittent annular shape. Alternatively, instead of (or together with) the second groove portion 143A, linear through-holes may be intermittently provided around the battery axis. The second groove portion 143A may be a groove having an opening facing outward from the battery axis. That is, the second groove portion 143A may have a groove opening on the surface of the second metal member 14A that faces relatively outside the battery 1a in the battery axis direction. Since the protruding portion 141A is connected to the first metal member 11A, when the first metal member 11A deforms outward toward the battery axis at an abnormally high temperature, the second metal member 14A also deforms, and the second metal member 14A may crack at the second groove portion 143A and separate into the protruding portion 141A and the other portion. Since it can be separated in this way, the current is interrupted.

[0088] The second metal member 14A may be a conductive member. For example, the second metal member 14A may contain any one or more of metal materials such as aluminum (e.g., aluminum alloys such as A1050, A3203, and A5052), titanium, platinum, and gold. Note that the material of the second metal member 14A may be the same as the material of the first metal member 11A, or may be a different material from the first metal member 11A.

[0089] Although the outer contour shape of the second metal member 14A in plan view is not particularly limited, it may be, for example, circular, polygonal, or other shapes. The outer contour shape of the second metal member 14A in plan view may be the same as the outer contour shape of the first metal member 11A in plan view. In the illustrated exemplary embodiment, the outer contour shape of the first metal member 11A in plan view is circular.

[0090] For example, the second metal member 14A may be entirely in a flat plate shape. That is, the second metal member 14A may have a form that extends on the same plane. For example, the second metal member 14A may have a substantially constant thickness except for the second groove portion 143A provided therein. Also, the central region of the second metal member 14A may be relatively thicker compared to the region other than that for the purpose of facilitating connection with the first metal member 11A. In other words, although the second metal member 14A has a plate-like shape as a whole, the thickness of the central portion of the region including the battery axis may be relatively larger than that of the outer peripheral portion 142A.

[0091] In the safety valve 10A, the first metal member 11A and the second metal member 14A are integrated with a second insulating member 15A interposed therebetween, while they may be electrically connected to each other in their central regions. For example, the first metal member 11A may be directly connected to the central region of the second metal member 14A so as to straddle the second insulating member 15A. More specifically, as shown in FIG. 4, the central region of the first metal member 11A and the central region of the second metal member 14A may be directly connected to each other through the opening region of the second insulating member 15A. In such a case, further, the central region of the first metal member 11A and the central region of the second metal member 14A may be electrically connected.

[0092] The second metal member 14A may have a plurality of openings arranged concentrically from the center (battery axis) in a plan view. The openings can serve as passage ports for the gas generated during abnormal high temperatures.

[0093] -Second Insulating Member- The second insulating member 15A corresponds to a member that is interposed between the first metal member 11A and the second metal member 14A and enables at least the connection between the first metal member 11A and the second metal member 14A. The second insulating member 15A insulates the electrical connection at the respective peripheral edges of the first metal member 11A and the second metal member 14A. Thereby, the first metal member 11A is electrically connected only to the protruding portion 141A of the second metal member 14A. For this reason, when the second metal member 14A cracks due to the gas generated during abnormal high temperatures, the current can be interrupted.

[0094] The second insulating member 15A may have an annular shape as a whole. That is, the planar shape of the second insulating member 15A may be a ring shape or a circular shape, etc. Due to such an annular shape, ring shape, or circular shape, the central region of the second insulating member 15A may form a hollow portion or an opening region. Although the outer contour shape of the second insulating member 15A in plan view is not particularly limited, it may be the same as the outer contour shape of the first metal member 11A in plan view, or may be the same as the outer contour shape of the second metal member 14A in plan view. For example, the outer contour shape in plan view can be circular. Note that such an annular shape, ring shape, or circular shape of the second insulating member 15A may be in a continuous form as a whole member, or may be in a form that is locally segmented and / or notched.

[0095] The second insulating member 15A may be, for example, flat as a whole. That is, the second insulating member 15A may have a form that extends on the same plane. Although it is only an example, the second insulating member 15A may have a substantially constant thickness between the first metal member 11A and the second metal member 14A.

[0096] The second insulating member 15A is a member having insulating properties. Therefore, electrical conduction through the second insulating member 15A is preferably prevented. In this specification, "insulation" may have the electrical resistivity of a general insulator due to the insulating properties of a general insulator. Although it is only an example, the second insulating member 15A may have a resistivity (room temperature 20°C) of at least 1.0×10 5 Ω·m or more, preferably 1.0×10 6 Ω·m or more, more preferably 1.0×10 7 Ω·m or more. Note that the first insulating members 13A and 13B can also have the same resistivity as the second insulating member 15A.

[0097] In a preferred embodiment, the second insulating member 15A interposed between the first metal member 11A and the second metal member 14A is adhered to them. In other words, the second insulating member 15A may be interposed between the first metal member 11A and the second metal member 14A as an adhesive layer. Preferably, the second insulating member 15A may be interposed between the first metal member 11A and the second metal member 14A such that an opening region of the insulating member is positioned in a region including the battery axis. The opening region is positioned at a location corresponding to the central region of the first metal member 11A. The planar shape of the opening region is not particularly limited and may be, for example, the same as the outer contour shape of the first metal member 11A in plan view. In the illustrated exemplary embodiment, the planar shape of the opening region is circular.

[0098] The second insulating member 15A is preferably made of an insulating resin material. This is because the resin material can suitably contribute to the adhesion between the first metal member 11A and the second metal member 14A while ensuring insulation, and thus helps to realize a thinner safety valve 10A. When the second insulating member 15A is made of a resin material, for example, the second insulating member 15A may be made of a thermosetting resin, a thermoplastic resin, and / or a UV-curable resin. From the perspective of adhesion, the second insulating member 15A may be a member containing a resin adhesive exhibiting insulation. Examples of such resin adhesives include acrylic resin adhesives such as acrylate copolymers, silicone resin adhesives such as silicone rubber, urethane resin adhesives such as urethane resin, α-olefin resin adhesives, ether resin adhesives, ethylene-vinyl acetate resin adhesives, epoxy resin adhesives, vinyl chloride resin adhesives, chloroprene rubber resin adhesives, cyanoacrylate resin adhesives, aqueous polymer-isocyanate resin adhesives, styrene-butadiene rubber resin adhesives, nitrile rubber resin adhesives, nitrocellulose resin adhesives, reactive hot melt resin adhesives, phenol resin adhesives, silicone resin adhesives, polyamide resin adhesives, polyimide resin adhesives, polyurethane resin adhesives, polyolefin resin adhesives, polyvinyl acetate resin adhesives, polystyrene resin solvent adhesives, polyvinyl alcohol resin adhesives, polyvinyl pyrrolidone resin adhesives, polyvinyl butyral resin adhesives, polybenzimidazole resin adhesives, polymethacrylate resin adhesives, melamine resin adhesives, urea resin adhesives, and / or resorcinol resin adhesives, etc.

[0099] -Top Cover- As described above, the safety valve 10A may further include a top cover 16A. That is, the top cover 16A may be further provided relatively outside in the battery axial direction than the first metal member 11A. The top cover 16A may be provided with a plurality of openings. These plurality of openings mainly correspond to discharge ports that contribute to the passage or release of the gas outside the exterior body 20 when the gas inside the exterior body 20 leaks from the cracked portion of the first metal member 11A.

[0100] The top cover 16A is a conductive member and may be, for example, a metal member. For example, the top cover 16A may contain any one or more of metal materials such as aluminum (such as aluminum alloys such as A1050, A3203, and A5052), titanium, platinum, iron, and gold. Further, the metal member may be plated with another metal on these metals. For example, it may be a nickel-plated iron.

[0101] The top cover 16A is preferably electrically connected to the first metal member 11A. In such a case, the top cover 16A can function as an external terminal of the battery 1a. For example, the top cover 16A may function as the positive terminal of the battery, and the exterior body 20 may function as the negative terminal. Therefore, the top cover 16A and the exterior body 20 may be insulated from each other.

[0102] The safety valve 10A is connected to a conductive member extending from the battery assembly. More specifically, the conductive member is connected to the second metal member 14A of the safety valve 10A. In particular, the conductive member 15 may be connected to a non-central region, which is a region on the outer peripheral side of the second groove portion 143A of the second metal member 14A. The "non-central region" is a region other than the central region on the inner peripheral side of the second groove portion 143A, and can also be referred to as the "outer peripheral region". The conductive member 15 is electrically connected to the battery assembly (particularly, either the positive electrode or the negative electrode thereof), and contributes to the electrical connection between the battery assembly and the safety valve 10A (particularly, the second metal member 14A). In the safety valve 10A, the second metal member 14A is electrically connected to the first metal member 11A through its central region. Further, the first metal member 11A is electrically connected to the top cover 16A that forms an external terminal of the battery. Therefore, the battery assembly such as the wound structure is electrically connected to the external terminal of the battery 1a through the conductive member 15.

[0103] [First Metal Member Cracking Mechanism] With reference to FIGS. 4 and 6, the operation of the safety mechanism (first metal member cracking mechanism) related to the battery 1a will be described.

[0104] For example, when gas is generated inside the exterior body 20 due to a side reaction such as the decomposition reaction of the electrolytic solution accompanying overcharging, the gas accumulates inside the exterior body 20, and the internal pressure of the exterior body 20 rises. If the internal pressure of the exterior body 20 continues to rise, the second metal member 14A and the first metal member 11A are affected by the rise in such internal pressure. When the internal pressure of the exterior body 20 exceeds a predetermined pressure, as shown in FIG. 6, the central region of the first metal member 11A is pushed upward and displaced toward the outside of the battery along the battery axis P direction. Along with such displacement, the central region of the second metal member 14A is also pushed upward in the displacement direction and breaks starting from the second groove portion 143A provided in the second metal member 14A. "Breaking" as used in this specification means that the connection is completely severed. As a result, the second metal member 14A is divided into a central region on the inner peripheral side of the second groove portion 143A and a non-central region on the outer peripheral side of the second groove portion 143A. More specifically, the second metal member 14A is divided into a central region connected to the first metal member 11A and a non-central region connected to the conductive member. As can be seen from the form shown in FIG. 6, due to such division, the first metal member 11A and the non-central region of the second metal member 14A are physically separated from each other. Therefore, the electrical connection between the top cover 16A and the battery assembly is severed, and the current path flowing between the top cover 16A and the battery assembly is interrupted. In this way, it becomes possible to cut off the current of the battery 1a when the internal pressure abnormally rises.

[0105] After the above-described first metal member cracking mechanism operates, if the displacement of the first metal member 11A due to the internal pressure further progresses, the first metal member 11A may crack or break starting from the first groove portion 111A provided in the first metal member 11A (see FIG. 6). Here, the first metal member 11A is displaced so as not to contact the top cover 16A. "Cracking" as used herein includes a form in which at least a part is separated while a part remains continuous. That is, the first metal member 11A may or may not be completely separated between the central region on the inner peripheral side of the first groove portion 111A and the non-central region on the outer peripheral side of the first groove portion 111A. When the first metal member 11A cracks, the inside and outside of the battery 1a communicate with each other. As a result, the gas inside the exterior body 20 is released to the outside from the cracked portion, and the internal pressure is reduced. In such a case, the gas discharge path through the plurality of openings formed in the top cover 16A is released, and the gas can be discharged to the outside of the battery via the open portion. In one aspect, the second metal member 14A may also be provided with an opening, and the gas inside the exterior body 20 may be discharged to the outside through the second metal member 14A.

[0106] The battery 1a includes a heat release mechanism and a first metal member cracking mechanism. These mechanisms operate when the internal pressure reaches a certain threshold value. The first insulating member release pressure P 1 of the heat release mechanism is smaller than the safety valve cracking pressure P 2 of the first metal member cracking mechanism. Therefore, in an abnormally high temperature state, when the internal pressure of the battery 1a increases, first the heat release mechanism acts, and then the first metal member cracking mechanism operates.

[0107] <Other Embodiments> As described above, the embodiments of the present disclosure have been described. However, the above-described embodiments are merely illustrative examples. The present disclosure is not limited to the above-described embodiments, and design changes can be made without departing from the gist of the present disclosure. Also, the configurations in the first embodiment and the second embodiment may be combined in various ways.

[0108] In the second embodiment, the battery 1a has the first metal member cracking mechanism only in one of the safety valves 10A, but is not limited thereto. For example, the battery may have the current cracking mechanism in both of the safety valves 10A and 10B arranged at both ends. In this aspect, the safety is further improved as compared with the battery 1a according to the second embodiment.

[0109] The battery aspect according to the present disclosure is as follows. <1> A cylindrical battery including a cylindrical exterior body that houses a battery element and safety valves arranged at both ends of the exterior body, wherein the safety valve has a first metal member, a support portion provided to support the first metal member at a peripheral edge portion of the first metal member and having an opening, and a first insulating member that connects the first metal member and the support portion and includes a thermoplastic resin. <2> The battery according to <1>, wherein the thermoplastic resin includes at least one resin selected from the group consisting of a super engineering plastic resin and a polyolefin resin. <3> The battery according to <1> or <2>, wherein in a normal state, the first insulating member seals between the metal member and the support portion. <4> The battery according to any one of <1> to <3>, wherein in an abnormally high temperature state, the thermoplastic resin softens to form a gas discharge path that communicates the inside of the battery and the outside of the battery. <5> The battery according to any one of <1> to <4>, wherein an outer surface of the exterior body has a structure that does not include a beading portion. <6> At least one of the safety valves arranged at both ends further includes a second metal member provided on an inner surface side of the first metal member and electrically connected to the first metal member, and a second insulating member that connects peripheries of the first metal member and the second metal member and includes a thermosetting resin. The first metal member has a first groove portion on the radially inner side perpendicular to the battery axis corresponding to the rotation axis of the cylindrical battery with respect to the connection portion between the first metal member and the periphery of the second metal member. The second metal member has a central portion electrically connected to the first metal member, a second groove portion, and an outer peripheral portion surrounding the central portion via the second groove portion. The battery according to any one of <1> to <5>. <7> The second metal member is disposed in the opening of the support portion. The second metal member is disposed at the center, protrudes outward relative to the battery axis, and has a protruding portion electrically connected to the first metal member. A peripheral edge portion disposed on the peripheral edge of the protruding portion and connected to the first metal member via the second insulating member. The battery according to <6>, having <8> In a normal state, the second metal member electrically connects the first metal member and the battery element. The battery according to <6> or <7>. <9> At an abnormally high temperature, the central portion of the second metal member separates from the outer peripheral portion, the first metal member is displaced, and the electrical connection between the first metal member and the outer peripheral portion of the second metal member is interrupted. The battery according to any one of <6> to <8>. <10> The first metal member has an outer peripheral portion extending radially of the battery axis to the outside of the second metal member. The support portion is overlapped with the outer peripheral portion in the battery axis direction via the first insulating member. The battery according to any one of <6> to <9>. <11> Both of the safety valves disposed at both ends are provided on the inner surface side of the first metal member and have a second metal member electrically connected to the first metal member. A second insulating member connecting the peripheries of the first metal member and the second metal member and containing a thermosetting resin. Further comprising The first metal member has a first groove portion on the inner side in the radial direction perpendicular to the battery axis corresponding to the rotation axis of the cylindrical battery, with respect to the connection portion between the first metal member and the periphery of the second metal member. The second metal member has a central portion electrically connected to the first metal member, a second groove portion, and an outer peripheral portion surrounding the central portion via the second groove portion. The battery according to any one of <6> to <10>.

Example

[0110] Hereinafter, the present invention will be described more specifically using examples. The present disclosure is not limited by the following examples at all.

[0111] <Example 1> [1. Preparation of Test Battery] A secondary battery having the following specifications was prepared. Table 1 summarizes the configuration of Example 1. · Shape: Cylindrical (diameter dimension: about 22 cm, axial length: about 70 mm) · Positive and negative electrodes of the electrode assembly: Positive and negative electrodes capable of intercalating and deintercalating lithium ions · Nominal capacity: about 4100 mAh · Nominal voltage: 3.6 V · Both ends: Three-piece structure composed of a first metal member, a support portion, and a first insulating member (hereinafter, also referred to as a "thermal release mechanism") (Materials of each member) · Safety cover (first metal member): Made of metal (metal containing aluminum) · First insulating member: Made of thermoplastic resin (polypropylene (PP)) · Outer package and support portion: Made of metal (metal containing aluminum)

[0112]

Table 1

[0113] [2. Safety Test] (2-1. UL Projectaile Test (Burner Test)) The UL Projectile test (burner test) compliant with the UL1642 standard was conducted. Specifically, the battery of Example 1 prepared was fully charged. The fully charged battery was fixed with wire on a heating table. The periphery of the fixed battery was covered with an octagonal 17-mesh aluminum net. In this state, the battery was heated with a burner from below the heating table, and the heating was continued until the battery caught fire or burst. The temperature of the flame of the burner was 700 - 740°C. The state of the battery that caught fire or burst was observed visually. Based on the observation results, the safety of the battery of Example 1 was evaluated according to the following evaluation criteria. The evaluation results of the safety are summarized in Table 1. [Evaluation Criteria] Pass (Qualified: Good): The members of the battery that caught fire or burst protrude outside from the 17-mesh aluminum net made of aluminum. NG (Unqualified: Bad): The members of the battery that caught fire or burst do not protrude outside from the 17-mesh aluminum net made of aluminum.

[0114] (2 - 2. Change in internal pressure of the battery in an abnormally high temperature state) For the example where the result of the UL Projectile test in 2 - 1 was "Pass", the time change of the internal pressure of the battery in the abnormally high temperature state of the battery was further considered. This will be described with reference to Table 1 and Figure 8. Figure 8 is a diagram schematically showing the time change of the internal pressure in the batteries of the examples and comparative examples.

[0115] In Figure 8, the vertical axis indicates the internal pressure of the battery (cell internal pressure), and the horizontal axis indicates time. It is assumed that thermal runaway occurs from time T 1 to T 2 . That is, time T 1 indicates the thermal runaway start time, and time T 2 indicates the time when thermal runaway ends. On the other hand, in ascending order from the side closer to 0 (zero) on the vertical axis, P 1 , P 2 , P 3 , and P 4 The pressures lined up are the P 1 (first insulation member opening pressure) of the heat release mechanism, and the P 2 of the first metal member cracking mechanism, respectively.(Safety valve cracking pressure), P of the marking mechanism 3 (Bottom of can marking cracking pressure), and P 4 (Welded joint opening pressure resistance or crimp opening pressure resistance). In addition, at the ends of the batteries used in Example 1 and Examples 2 to 5 and Comparative Examples 1 to 6 described later, any one of a thermal release mechanism, a thermal release mechanism + first metal member cracking mechanism, a first metal member cracking mechanism, a marking mechanism, and no safety mechanism was adopted.

[0116] In the battery of Comparative Example 2, the internal pressure is considered to change as shown in Mode 1 (represented by a solid line in Fig. 8). Specifically, the battery of Comparative Example 2 adopted a first metal member cracking mechanism at the upper end and a marking mechanism at the lower end. Therefore, in the battery of Comparative Example 2, when an abnormally high temperature state occurs, gas is generated inside, so the internal pressure gradually increases from time 0 to T 1 to change. In Comparative Example 2, since no thermal release mechanism is adopted, P 1 the internal pressure does not decrease. As the internal pressure further increases and reaches P 2 , the first metal member cracking mechanism operates. That is, the central part of the second metal member separates, and the first metal member deforms and cracks, thereby reducing the internal pressure. Next, from time T 1 to T 2 as it increases, as the internal pressure further increases and reaches P 3 , the marking mechanism operates and the internal pressure slightly decreases. Next, the internal pressure reaches P 4 .

[0117] In the battery of Comparative Example 3, the internal pressure is considered to change substantially as shown in Mode 1 (represented by a solid line in Fig. 8). Specifically, in the battery of Comparative Example 3, a first metal member cracking mechanism was adopted at both the upper and lower ends. Therefore, at P 2 since the first metal member cracking mechanisms at both ends operate, it is considered that the pressure decreases significantly compared to Mode 1 in Fig. 8. On the other hand, at P 3 since the marking mechanism does not operate, the internal pressure does not decrease. As a result, similar to Comparative Example 2, it is considered that the internal pressure reaches P 4 early.

[0118] Also, in the battery of Comparative Example 6, it is considered that the internal pressure undergoes the change shown in Mode 2 (indicated by the broken line in FIG. 8). Specifically, the battery of Comparative Example 6 employed a heat release mechanism at the upper end and an imprinting mechanism at the lower end. Therefore, in the battery of Comparative Example 6, when it reaches an abnormally high temperature state, gas is generated inside, so the internal pressure gradually increases from time 0 to T 1 and increases gradually as it changes to T 1 . When the internal pressure reaches P 1 , the heat release mechanism operates, that is, the thermoplastic resin of the first insulating member softens and a gas discharge path is formed, so the internal pressure decreases. The internal pressure gradually increases as it increases from time T 2 to T 2 . Since Comparative Example 2 does not have a current interruption mechanism, it passes through P 3 and reaches P 3 . When the internal pressure reaches P 4 , the imprinting mechanism operates and the internal pressure decreases slightly. Then, the internal pressure reaches P 4 . Mode 2 is common with Mode 1 in that the internal pressure reaches P 4 , but it takes more time to reach P 2 , and the internal pressure increases relatively gently.

[0119] In the battery of Comparative Example 4, it is considered that the internal pressure undergoes almost the change shown in Mode 2 (indicated by the broken line in FIG. 8). Specifically, in the battery of Comparative Example 4, a first metal member cracking mechanism was employed at the upper end and a heat release mechanism was employed at the lower end. Therefore, since the first metal member cracking mechanism operates at P 2 , it is considered to decrease compared to Mode 2 in FIG. 8. On the other hand, since the imprinting mechanism does not operate at P 3 , the internal pressure does not decrease. As a result, similar to Comparative Example 6, it is considered that the internal pressure reaches P 4 with a delay.

[0120] In the batteries of Examples 1 to 4, it is considered that the internal pressure undergoes the change shown in Mode 3 (indicated by the dashed-dotted line in Fig. 8). Specifically, the batteries of Examples 1 to 4 adopted heat release mechanisms at the upper and lower end portions. Therefore, in the batteries of Examples 1 to 4, when in an abnormally high temperature state, gas is generated inside, and thus the internal pressure gradually increases from time 0 to T 1 and changes to T 1 . When the internal pressure reaches P 1 , the heat release mechanism activates and the internal pressure decreases. From time T 2 to T 4 , it gradually increases as it increases. However, since the internal pressure significantly decreases due to the heat release mechanism, it does not reach P

[0121] . The internal pressure increases relatively more gently with respect to Modes 1 to 2. 1 In addition to the decrease in the internal pressure due to the heat release mechanism at P 2 , since the first metal member cracking mechanism activates at P 2 , it is considered that it further decreases at P

[0122] compared to Mode 3 in Fig. 8. As a result, similar to Examples 1 to 4, it increases relatively gently. [Evaluation Criteria] Mode 3 (Good): The internal pressure does not reach P 1 within the time from T 2 or more to T 4 Mode 2 (Slightly Bad): The internal pressure reaches P 1 within the time from (T 2 + T 2 ) / 2 or more to T 4 ​​Mode 1 (bad): The internal pressure is T 1 or more (T 1 + T 2 ) / 2 or less within the time to reach P 4 arrive at NG (very bad): The result of the 2-1 US Projectile test is NG

[0123] <Examples 2 to 5 and Comparative Examples 1 to 6> [1. Preparation of test battery] A test battery was prepared in the same manner as in Example 1, except that the configuration of the battery was changed to the configuration described in Table 1. Specifically, the first metal member cracking mechanism employed in Example 5 and the like was a combination of the heat release mechanism of Example 1 with a top cover, a second insulating member, and a stripper disk. That is, the first metal member cracking mechanism had a valve configuration in which a top cover, a safety cover (first metal member), a second insulating member, and a stripper disk were combined in that order.

[0124] Also, the engraving mechanism employed in Comparative Example 2 and the like will be described with reference to FIG. 7. FIG. 7 is a plan view schematically showing the lower end portion of the comparative example. As shown in FIG. 7, the engraving mechanism has a C-shaped engraving portion at the lower end portion. The engraving portion is relatively thin. Further, the engraving portion can break to form a gas discharge path when gas is generated inside the battery in an abnormally high temperature state. However, the engraving mechanism is vulnerable to external stress such as impact during dropping, and there is a risk of reducing the safety in the normal state.

[0125] Also, the "-" in the "Presence and type of safety mechanism" column at the lower end portion of Comparative Examples 1 and 5 indicates that no safety mechanism is employed. In this case, the first metal member, the support portion, and the exterior body were connected by welding.

[0126] (Materials of each member) · Second insulating member: made of resin (resin containing PBT / polybutylene terephthalate resin) · Stripper disk: made of metal (metal containing aluminum) · First insulating member: made of a thermoplastic resin (polypropylene (PP) or polyphenylene sulfide (PPS))

[0127] [2. Evaluation] For the batteries of Examples 2 to 5 and Comparative Examples 1 to 6, safety tests were carried out in the same manner as in Example 1. The evaluation results are shown in Table 1.

[0128] <Results: Examples 1 to 5 and Comparative Examples 1 to 6> As shown in Table 1, in the batteries of Examples 1 to 5, both of the two ends included a first metal member, a support portion, and a first insulating member. Also, for the batteries of Examples 1 to 5, all of the UL Projectile tests passed, and the assumed modes of the Projectile test were all 3.

[0129] As shown in Table 1, in the batteries of Comparative Examples 1 to 6, neither of the two ends included a first metal member, a support portion, and a first insulating member. Specifically, in the batteries of Comparative Examples 1 to 4, the first insulating member was not provided at the upper end, and in the batteries of Comparative Examples 1 to 3 and 5 to 6, the first insulating member was not provided at the lower end. Also, in the batteries of Comparative Examples 1 to 6, neither of them satisfied both the passing of the UL Projectile test and the assumed mode of the Projectile test being 3. Specifically, in the batteries of Comparative Examples 1 and 5, the UL Projectile test failed. In the batteries of Comparative Examples 1 and 5, the assumed mode of the Projectile test failed, and in Comparative Examples 2 to 4 and 6, the assumed mode of the Projectile test was 1 or 2.

[0130] From the above, it is clear that Examples 1 to 5 included in the scope of the invention according to claim 1 are more excellent in safety than Comparative Examples 1 to 6 not included in the scope of the invention according to claim 1.

[0131] Note that the effects of the above embodiments are merely illustrative. Therefore, the present disclosure is not limited to the above matters, and there may be additional effects.

Industrial Applicability

[0132] The battery according to the present disclosure (such as primary batteries and secondary batteries) can typically be used in applications where the use of electrical energy is required. For example, the (secondary) battery according to the present disclosure can be used in various fields where power storage is assumed. Although merely illustrative, the (secondary) battery of the present disclosure can be used in the electrical, information, and communication fields (for example, the fields of mobile phones, smartphones, notebook computers, digital cameras, activity monitors, arm computers, electronic paper, wearable devices, etc., and small electronic devices such as RFID tags, card-type electronic money, smartwatches, etc. in the electrical and electronic device fields or mobile device fields), home and small industrial applications (for example, the fields of power tools, golf carts, home, care, and industrial robots), large industrial applications (for example, the fields of forklifts, elevators, and port cranes), transportation system fields (for example, the fields of hybrid vehicles, electric vehicles, buses, trains, electric assist bicycles, electric motorcycles, etc.), power system applications (for example, the fields of various power generations, load conditioners, smart grids, general household installed power storage systems, etc.), medical applications (the field of medical devices such as earphone hearing aids), pharmaceutical applications (the field of medication management systems), as well as the IoT field, space and deep sea applications (for example, the fields of space exploration machines, submersible research vessels, etc.).

Explanation of Signs

[0133] 1, 1a Battery 10A, 10B Safety Valve 11A, 11B First Metal Member 111A First Groove Portion 12A, 12B Support Portion 13A, 13B First Insulating Member 14A Second Metal Member 141A Protrusion 142A Outer Peripheral Portion 143A Second groove portion 15A Second insulating member 20 Exterior body

Claims

1. A cylindrical battery comprising a cylindrical exterior body for housing a battery element and safety valves disposed at both ends of the exterior body, wherein the safety valve comprises a first metal member, a support portion provided to support the first metal member at a peripheral edge portion of the first metal member and having an opening, and a first insulating member that connects the first metal member and the support portion and comprises a thermoplastic resin.

2. The battery according to claim 1, wherein the thermoplastic resin comprises at least one resin selected from the group consisting of super engineering plastics resins and polyolefin resins.

3. In a normal state, the first insulating member seals between the metal member and the support portion. The battery according to claim 1.

4. In an abnormally high temperature state, the thermoplastic resin softens to form a gas discharge path that communicates the inside and the outside of the battery. The battery according to claim 1.

5. The outer surface of the exterior body has a structure without a beading portion. The battery according to claim 1.

6. At least one of the safety valves disposed at both ends further comprises a second metal member provided on an inner surface side of the first metal member and electrically connected to the first metal member, and a second insulating member that connects the peripheries of the first metal member and the second metal member and comprises a thermosetting resin, wherein the first metal member has a first groove portion on an inner side in a radial direction perpendicular to a battery axis corresponding to a rotation axis of the cylindrical battery with respect to a connection portion between the first metal member and the periphery of the second metal member, The second metal member has a central portion electrically connected to the first metal member, a second groove portion, and an outer peripheral portion surrounding the central portion via the second groove portion. The battery according to claim 1.

7. The second metal member is disposed in the opening of the support portion, wherein the second metal member has a protruding portion disposed at the center and protruding outward relatively to the battery axis and electrically connected to the first metal member, and a peripheral portion disposed at a periphery of the protruding portion and connected to the first metal member via the second insulating member. The battery according to claim 6.

8. In a normal state, the second metal member electrically connects the first metal member and the battery element. The battery according to claim 6.

9. ​ The battery according to claim 8, wherein at an abnormally high temperature, the central portion of the second metal member is separated from the outer peripheral portion, the first metal member is displaced, and the electrical connection between the first metal member and the outer peripheral portion of the second metal member is interrupted.

10. The first metal member has an outer peripheral portion extending outward beyond the second metal member in the radial direction of the battery axis. The battery according to claim 6, wherein the support portion is overlapped with the outer peripheral portion in the battery axis direction via the first insulating member.

11. Both of the safety valves disposed at both ends are provided on the inner surface side of the first metal member, and include a second metal member that is electrically connected to the first metal member, and a second insulating member that connects the peripheries of the first metal member and the second metal member and contains a thermosetting resin. The battery further comprises: The first metal member has a first groove portion radially inward perpendicular to the battery axis corresponding to the rotation axis of the cylindrical battery, with respect to the connection portion between the first metal member and the periphery of the second metal member. The battery according to claim 6, wherein the second metal member has a central portion electrically connected to the first metal member, a second groove portion, and an outer peripheral portion surrounding the central portion via the second groove portion.

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