JP2000340265A - Flat type stacked secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce and add necessary characteristics according to the using purpose and improve the applicability by forming an opening penetrating vertically in the central part of a battery element having a positive electrode material and a negative electrode material laminated via nonfluxional electrolyte layer including ionic metal salt. SOLUTION: An opening 6 penetrating vertically is formed in a central part of a battery element 4. Viewing the battery element from the upward, the opening penetrating vertically, or a through hole or a groove by a notch is formed toward inside than the circumferential part. The through hole is provided in the central part of a planar battery element 4 of circular, rectangular, triangular, or polygonal shape or a notch is provided from the side toward the inside direction so that the opening part 6 is formed. A positive electrode material 1 and a negative electrode material 2 are laminated via a nonfludization electrolyte layer 3 and current collecting elements 5a, 5b of the positive electrode material 1 and the negative electrode material 2 are connected to each other so that the battery element 4 of large capacity can be provided. Preferably, a fastening material is inserted in the opening part 6 to apply a force of vertically nippedly pressurizing the battery element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat secondary battery and, more particularly, to a secondary battery using a battery element which is useful for enhancing characteristics according to purposes.

[0002]

2. Description of the Related Art In recent years, demand for batteries has been rapidly increasing with the development of portable electronic devices, and the demand for backup batteries has been steadily increasing with the spread of personal computers and word processors. As batteries used in these applications, the demand for rechargeable and long-life rechargeable batteries is rapidly increasing, and lithium is used as an electromotive substance, and carbon or lithium capable of absorbing lithium by intercalation is used. Attention has been paid to lithium secondary batteries using chalcogen compounds.

However, lithium has an extremely high activity with respect to water, and has problems such as ignition due to liquid leakage or inactivation of lithium due to invasion of air or moisture, and the sealing thereof is required to have a high degree of sealing. . As means for reducing such troubles, the electrolyte filled between the positive electrode and the negative electrode is made non-fluid by gelation or the like to prevent liquid leakage. By making the electrolyte non-fluidized, the coating is facilitated and the safety is improved, and the generation of dentite, which is a problem in lithium batteries, is suppressed, and the durability is improved.

In the production of a non-fluid electrolyte secondary battery, a flat cathode material, a porous membrane (separator) or a negative electrode material is impregnated with an electrolyte solution containing a gelling agent and then laminated. Proposed. For example, as shown in FIG. 11, the positive electrode material 1 or the negative electrode material 2 is formed on the surfaces of the current collectors 5a and 5b.
Are laminated to form a plate-shaped electrode material, and a large-capacity battery is attempted by laminating a plurality of positive electrode materials 1 and negative electrode materials 2 via a non-fluid electrolyte layer 3.

However, in such a structure, if the electrode material is enlarged in order to increase the battery capacity, it becomes difficult to apply the upper and lower clamping force, and when used in equipment having strong vibration, delamination may occur. is there. When peeling occurs between the positive electrode material, the separator, or the negative electrode material, the electrical resistance increases, so that there is a problem in that the rate characteristics, cycle characteristics, and the like decrease. In addition, when the battery element is used in an environment where an external force acts, the battery element, particularly the non-fluid electrolyte layer, may buckle due to the external force and the characteristics may be deteriorated.

Further, there is a possibility that the temperature of the secondary battery may rise due to an overcurrent at the time of charging or discharging, and it may be necessary to provide a protective element such as a PTC for suppressing the current at the time of heating. In such a case, in the case of a plate-shaped electrode material as shown in FIG. 11, the arrangement position of the protection element is restricted to the side of the battery element. For this reason, the thermal responsiveness of the protection element deteriorates,
There is a problem that current control is performed when the temperature of the electrode material rises. For this reason, development of a battery element having wide applicability that can enhance and impart necessary characteristics according to the purpose of use is desired.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a secondary battery using a battery element having excellent applicability which can enhance and impart necessary characteristics according to the purpose of use.

[0008]

Means for Solving the Problems The present invention has been made as a result of diligent studies to achieve the above object, and the positive electrode material and the negative electrode material comprise a non-fluid electrolyte layer containing an ionic metal salt. The present invention provides a flat-plate type laminated secondary battery in which an opening vertically penetrating is formed at the center of the battery element in a secondary battery in which battery elements stacked via the battery are housed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, in a secondary battery of the present invention, at least one of a plate-like positive electrode material 1 and a negative electrode material 2 electrically connected to a current collector 5 contains an ionic metal salt. The contained non-fluid electrolyte is applied, and as shown in FIG. 2, the positive electrode material 1 and the negative electrode material 2 are laminated with the non-fluid electrolyte layer 3 interposed therebetween. The ionic metal salt is a salt containing a metal component that forms an ion and electrochemically participates in charging and discharging of the secondary battery and generates an electromotive force, and a lithium salt is usually used. In general, a metal foil such as an aluminum foil or a copper foil can be used as the current collector. The thickness is appropriately selected, but is preferably 1 to 30 μm. If the thickness is too small, the mechanical strength becomes weak, which causes a problem in production. If it is too thick, the capacity of the battery as a whole decreases.

It is preferable that the surface of the current collector be subjected to a roughening treatment in advance, since the adhesive strength of the electrode material is increased. Examples of the surface roughening method include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method. Examples of the mechanical polishing method include a method of polishing the surface of the current collector with a polishing cloth paper having abrasive particles fixed thereon, a grindstone, an emery buff, a wire brush provided with a steel wire, or the like. Further, an intermediate layer may be formed on the surface of the current collector to increase the adhesive strength and the conductivity. Further, the shape of the current collector may be plate-like, or may be a net-like body or a punching metal. For materials that can be used for the positive electrode material 1, the negative electrode material 2, and the electrolyte layer 3,
Although not particularly limited, a case of a lithium secondary battery using a preferably used non-fluid electrolyte will be described below.

The cathode material 1 usually contains a cathode material capable of inserting and extracting lithium ions and a binder. Cathode material 10
The ratio of the binder to 0 parts by weight is preferably 0.1%.
-30 parts by weight, more preferably 1-15 parts by weight. If the amount of the binder is too small, a strong electrode material will not be formed, and the object of the present invention of holding the electrode material will not be achieved. If the amount of the binder is too large, not only does the energy density and cycle characteristics have an adverse effect, but also when the electrode material is impregnated with an electrolyte component, the amount of voids in the electrode material is reduced, making it difficult to impregnate the electrolyte component.

Examples of the positive electrode material include various inorganic compounds such as transition metal oxides, composite oxides of lithium and transition metals, and transition metal sulfides. Here, the transition metal is F
e, Co, Ni, Mn and the like are used. Specifically, M
Transition metal oxide powders such as nO, V ₂ O ₅ , V ₆ O ₁₃ and TiO ₂ ; composite oxide powders of lithium and transition metals such as lithium nickelate, lithium cobaltate and lithium manganate; TiS ₂ , FeS And transition metal sulfide powders such as MoS ₂ . These compounds may be partially substituted with elements in order to improve their properties. In addition, polyaniline, polypyrrole, polyacene, disulfide compounds, polysulfide compounds,
Organic compounds such as N-fluoropyridinium salts can also be used. These inorganic compounds and organic compounds may be used as a mixture. The particle size of these positive electrode materials is usually 1 to 3.
0 μm, especially 1 to 10 μm, late characteristics,
Battery characteristics such as cycle characteristics are further improved.

As the binder used for the positive electrode material,
Alkane-based polymers such as polyethylene, polypropylene and poly-1,1-dimethylethylene; unsaturated polymers such as polybutadiene and polyisoprene; and polymers having a ring such as polystyrene, polymethylstyrene, polyvinylpyridine and poly-N-vinylpyrrolidone Acrylic derivative polymers such as poly (methyl methacrylate), poly (ethyl methacrylate), poly (butyl methacrylate), poly (methyl acrylate), poly (methyl acrylate), poly (acrylic acid), poly (methacrylic acid), poly (acrylamide), polyvinyl fluoride, polyvinylidene fluoride , A fluororesin such as polytetrafluoroethylene, a CN group-containing polymer such as polyacrylonitrile and polyvinylidene cyanide, and a polyvinyl alcohol-based polymer such as polyvinyl acetate and polyvinyl alcohol. Mer, polyvinyl chloride, halogen-containing polymers such as polyvinylidene chloride, various resins such as a conductive polymer such as polyaniline can be used.
Further, a mixture of the above-mentioned polymers, a modified product, a derivative, a random copolymer, an alternating copolymer, a graft copolymer, a block copolymer, or the like can also be used. Also, inorganic compounds such as silicate and glass can be used.

The positive electrode material 1 may contain additives, such as a conductive material and a reinforcing material, exhibiting various functions such as a reinforcing material, a powder, a filler, and the like, if necessary. The conductive material is not particularly limited as long as it can impart conductivity by being mixed in an appropriate amount with the above substances, but usually, acetylene black, carbon black, carbon powder such as graphite, various metal fibers, foil and the like. No. As the reinforcing material, various inorganic or organic spherical or fibrous fillers can be used.

The negative electrode material 2 basically conforms to the structure of the positive electrode material except that a negative electrode material is used. Examples of the negative electrode material used for the negative electrode include a carbon-based material such as graphite and coke. These carbonaceous materials are metals and their salts,
It can also be used in the form of a mixture with an oxide or a coating.
In addition, oxides such as silicon, tin, zinc, manganese, iron and nickel, or sulfates, and metal lithium and Li-
A lithium alloy such as Al, Li-Bi-Cd, and Li-Sn-Cd, a lithium transition metal nitride, and silicon can also be used. The particle size of these negative electrode materials is usually 1 to 50 μm.
m, particularly 15 to 30 μm, is preferable because battery characteristics such as initial efficiency, late characteristics, and cycle characteristics are improved.

The method of forming the positive electrode material 1 and the negative electrode material 2 may be any method, but it is preferable that the formed positive and negative electrode materials have voids into which the electrolyte component can be impregnated later. In addition, the same electrolyte as the non-fluid electrolyte layer 3 formed between the two electrode materials can be formed in the gap, and this can be integrally formed with the non-fluid electrolyte layer 3. As a preferable method for producing the electrode material having such a void, there is a method in which components constituting the electrode material are dispersed and coated with an appropriate solvent, and this is applied onto a long current collector and then dried. . Alternatively, a method of pressing or spraying the electrode material component onto the current collector may be used. The electrode material having a void may be at least one of the positive electrode material 1 and the negative electrode material 2. For example, the positive electrode material 1 is composed of a positive electrode material and a binder, has a structure having voids, and uses lithium metal as the negative electrode material. Although it is also possible, preferably, both the positive and negative electrode materials have a structure having a gap.

By adding a calendering step to the formed coating film, it is possible to consolidate the coating film and increase the filling amount of the electrode material. The degree of compaction is determined by the balance between the filling amount of the electrode material and the ionic conductivity of the electrolyte portion filling the void. As a method of applying the electrode material, slide coating, extrusion die coating, reverse roll, gravure, knife coater, kiss coater,
Various coating methods such as microgravure, rod coater and blade coater are possible. Of course, it is also possible to combine these application methods.

The thickness of the formed electrode material is usually 1 μm or more, preferably 5 μm or more, and usually 500 μm or less.
Preferably it is 300 μm or less. If it is too thick, the rate characteristics tend to decrease, and if it is too thin, the capacity tends to decrease.
The obtained positive electrode material 1 and negative electrode material 2 are laminated in a state having a predetermined gap, and are usually laminated via a porous film serving as a separator for avoiding a short circuit between the positive electrode material 1 and the negative electrode material 2. Before lamination, an electrolyte containing a polymerizable gelling agent, an ionic metal salt and a non-aqueous solvent is applied to the side of the positive electrode material 1 and the negative electrode material 2 having a structure having voids or a porous film. It is desirable to impregnate it.

When the voids of the positive electrode material and / or the negative electrode material are filled with the gel-like non-fluid electrolyte, the ion conduction of lithium ions is performed through the gel-like electrolyte to the gel-like electrolyte layer. Thereby, it is desirable that the non-aqueous electrolyte solution of all of the positive electrode, the negative electrode and the electrolyte layer becomes a gel state, and that a safe lithium secondary battery without liquid leakage can be obtained. In the present invention, it is desirable to apply a fluid material that can be a gel electrolyte by polymerizing as an electrolyte component, and to apply a predetermined treatment after the application to a non-fluid electrolyte.

As such an electrolyte component, those containing an electrolytic solution comprising an ionic metal salt such as a lithium salt and a solvent and a monomer which is a polymerizable gelling agent are preferable. In this case, the electrolytic solution is held in the polymer by polymerizing the monomer later. Examples of such a polymer include those formed by polycondensation of polyester, polyamide, polycarbonate, and polyimide; those formed by polyaddition such as polyurethane and polyurea; acrylic derivative-based polymers such as polymethyl methacrylate; Some products are produced by addition polymerization of polyvinyl acetate, polyvinyl acetate, etc. such as vinyl acetate and polyvinyl chloride.Since they are impregnated in the electrode material and polymerized, the control of polymerization is easy and no by-products are generated during polymerization. It is desirable to use a polymer produced by addition polymerization.

The ionic metal salt contained in the electrolytic solution is stable as an electrolyte with respect to the positive electrode material and the negative electrode material, and can transfer lithium ions to cause an electrochemical reaction with the positive electrode material or the negative electrode material. Any non-aqueous substance can be used. LiPF ₆ in particular, LiAsF _6, LiSbF _6, Li
BF ₄ , LiClO ₄ , LiI, LiBr, LiCl,
LiAlCl, LiHF ₂ , LiSCN, LiSO ₃ C
F _2, and the like. Among these, LiP
F ₆ and LiClO ₄ are preferred. The content of these electrolyte salts in the electrolyte is generally 0.5 to 2.5 mol.
/ L.

The electrolyte for dissolving the ionic metal salt is not particularly limited, but a non-aqueous solvent having a relatively high dielectric constant is preferably used. Specifically, a mixed solution of one or more selected from cyclic carbonates such as ethylene carbonate and propylene carbonate, and non-cyclic carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate is preferable. Further, those obtained by substituting a part of hydrogen atoms of these molecules with halogen or the like can also be used. As the polymer constituting the gel electrolyte, a polymer capable of appropriately holding the electrolytic solution and gelling is used. Usually, since the above-mentioned electrolytic solution has polarity, it is preferable that the polymer also has a certain degree of polarity.

Examples of monomers having a reactive unsaturated group forming a non-fluid electrolyte include acrylic acid, methyl acrylate, ethyl acrylate, ethoxyethyl acrylate, methoxyethyl acrylate, ethoxyethoxyethyl acrylate, and polyethylene glycol monoacrylate. , Ethoxyethyl methacrylate, methoxyethyl methacrylate, ethoxyethoxyethyl methacrylate, polyethylene glycol monomethacrylate,
N, N-diethylaminoethyl acrylate, N, N-
Dimethylaminoethyl acrylate, glycidyl acrylate, allyl acrylate, 2-methoxyethoxyethyl acrylate, 2-ethoxyethoxyethyl acrylate, acrylonitrile, N-vinylpyrrolidone, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol Diacrylate,
Diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and the like can be used, and those which are preferable in terms of reactivity, polarity, safety, and the like may be used alone or in combination.

As a method of polymerizing these monomers, there are methods using heat, ultraviolet rays, electron beams, etc., and a method using ultraviolet rays or heat, which can easily form the positive electrode material / electrolyte layer / negative electrode material integrally, is effective. is there. In this case, in order to make the reaction proceed effectively, a polymerization initiator which reacts with heat is added to the electrolyte to be impregnated. Usable thermal polymerization initiators include azo compounds such as azobisisobutyronitrile and dimethyl 2,2'-azobisisobutyrate, benzoyl peroxide, cumene hydroperoxide, t-amyl peroxy-2-ethyl-hexanoate. And peroxides such as t-butylperoxy-2-ethylhexanoate and the like, and those which are preferable in terms of reactivity, polarity, safety and the like may be used alone or in combination.

The electrolyte interposed between the positive electrode material 1 and the negative electrode material 2 is usually impregnated into a separator made of a porous film to form a non-fluid electrolyte layer 3. The porous membrane used must have sufficient mechanical strength to prevent short circuits during production or use, and ensure sufficient ionic conductivity of the electrolyte layer to sufficiently exhibit battery performance. is necessary. As a porous membrane satisfying such performance, specifically, a polyolefin or a hydrogen atom having a thickness of 1 μm or more, preferably 5 μm or more, usually 500 μm or less, preferably 200 μm or less and a porosity of 30 to 85% is used. A polyolefin membrane partially or wholly substituted with fluorine can be used. Specifically, a microporous film, a nonwoven fabric, a woven fabric, or the like formed using a synthetic resin such as polyolefin can be used.

The method of applying the electrolytic solution is not particularly limited, and the electrolytic solution may be applied to each of the positive and negative electrode materials cut into a shape described later and laminated. Alternatively, the long positive electrode material and the long negative electrode material may be coated with an electrolytic solution, cut into respective predetermined shapes, and laminated with a separator as necessary. Further, the long positive electrode material 1 and the negative electrode material 2 to which the electrolytic solution is applied are laminated by interposing a separator as necessary, and after the non-fluidizing treatment of the electrolytic solution is performed, the whole is formed into a predetermined shape. It can also be cut. After laminating the electrode material,
By performing the non-fluidization treatment of the electrolytic solution, the rate characteristics can be improved.

There are no particular restrictions on the method of applying the electrolytic solution, and slide coating, extrusion die coating, reverse coating, knife coater,
A kiss coater, microgravure, rod coater, blade coater, multi-nozzle dispenser, or the like can be used. At this time, it is desirable that the electrolytic solution used for coating is kept at 15 ° C. or lower in the supply tank. Further, instead of applying the electrolytic solution to the positive electrode material 1 and the negative electrode material 2, or together with the application of the electrolytic solution to the positive electrode material 1 and the negative electrode material 2, the electrolytic solution can be applied to the porous film.

Thus, in the present invention, as shown in FIGS. 1 to 3, an opening vertically penetrating the battery element 4 is formed at the center. In the present invention, the central portion of the battery element does not need to be strict, and an opening that vertically penetrates the battery element inside the peripheral portion when viewed from above, that is, a groove formed by a through hole or a notch is formed. You. Generally, when viewed from the top, the opening penetrates vertically at a position of 20 to 80, preferably 30 to 70 when both ends of a straight line drawn from one side to the other side of the diameter, diagonal line, or other side are 0 to 100. Section. Specifically, as shown in FIG. 6, a through-hole may be provided at the center of the plate-shaped battery element 4 such as a circle, a square, a triangle, and a polygon to penetrate vertically, and as shown in FIG. The opening 6 can also be provided by forming a notch from the side toward the inside.

When the electrode material thus obtained is formed on both sides of the current collector as shown in FIG. 1, the positive electrode material 1 and the negative electrode material 2 are formed as shown in FIG. A large-capacity battery element can be obtained by laminating via the layer 3 and connecting the current collectors 5a and 5b of the positive electrode material 1 and the negative electrode material 2 respectively. When the electrode material is formed on one surface of the current collector 5, as shown in FIG. 5, a unit cell including the positive electrode material 1, the non-fluid electrolyte layer 3 and the negative electrode material 2 is used as a unit cell. The battery element 4 can also be formed by laminating the negative electrode material 2 and the negative electrode material 2 in the facing direction.

The positive electrode material 1, the non-fluid electrolyte layer 3 and the negative electrode material 2 may have the same dimensions as shown in FIGS. 2 and 3. However, as shown in FIG. By changing the dimensions of the material 2 and providing a distance between the edges thereof, it is possible to prevent the danger of a short circuit due to the occurrence of dentite. When a secondary battery is formed by using the battery element 4 obtained in this manner, a clamping pressure for preventing delamination of the battery element 4,
Alternatively, when supporting an external force for enhancing the strength against the external force, as shown in FIG.
It can be sealed with a box-shaped covering material 11 having 0 and fastened with bolts 12. In addition, 14 is a sealing tape for improving the sealing property of the covering material 11, and 15 is an elastic body for clamping the battery element 4.

Further, as shown in FIG. 9, a fitting portion 13 is formed in the sleeve portion 10 and press-fitted to engage with the sleeve portion 10, so that the sleeve portion 10 can be easily fastened. It is also possible to use an ultrasonic welding machine instead of the bolt 12 and the fitting portion 13 for sealing. When protecting from a temperature rise due to an overcurrent, a cylindrical protection element 16 is disposed around the sleeve portion 10 of the covering material 11 as shown in FIG. To be

When the temperature of the protection element 16 rises due to an increase in ambient temperature or heat generation due to an overcurrent,
An element having a positive temperature resistance characteristic in which the resistance value sharply increases at a predetermined temperature, and is generally a PTC (Positive) element.
ve Temperature Coefficien
t) A commercially available product such as a thermistor can be used. Further, it is desirable that the protection element 16 use a reset type in which the resistance value returns to the original state when cooled after the resistance increases due to a rise in temperature. With this configuration, since the protection element 16 is located at the center of the battery element 4, it is possible to sensitively sense the temperature rise of the battery element 4, and to obtain a secondary battery with excellent thermal response. it can.

Since the thickness of the battery is not increased by the protection element 4, the electric capacity per volume can be increased as a result. The material of the coating material 11 used for sealing may be any material as long as it is tough and has low moisture permeability, and polyolefin, polycarbonate, polyester, polyamide, and the like can be used.
Further, it is desirable that the gas barrier property is enhanced by laminating one or more metal thin-film layers of aluminum, copper, or the like.

[0034]

According to the present invention, since the opening is provided at the center of the battery element, necessary characteristics can be enhanced, and a secondary battery having a wide applicability can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of an electrode material used in the present invention.

FIG. 2 is a longitudinal sectional view showing an example of the battery element of the present invention.

FIG. 3 is a plan view of the battery element of FIG. 2;

FIG. 4 is a plan view showing another example of the battery element.

FIG. 5 is a longitudinal sectional view showing another example of a battery element.

FIG. 6 is a plan view showing an example of the electrode material of the present invention.

FIG. 7 is a plan view showing another example of the electrode material of the present invention.

8A is a longitudinal sectional view showing an example of the secondary battery of the present invention, and FIG. 8B is a transverse sectional view thereof.

FIG. 9 is a longitudinal sectional view showing a sleeve portion of the coating material.

FIG. 10 is a longitudinal sectional view of a protection element portion showing an example in which a protection element is mounted on the secondary battery of the present invention.

FIG. 11 is a longitudinal sectional view of a conventional battery element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode material 2 Negative electrode material 3 Non-fluid electrolyte layer 4 Battery element 5a, 5b Current collector 6 Opening 10 Sleeve part 11 Covering material 12 Bolt 13 Fitting part 16 Protection element

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Masaaki Mita 3-10-10 Shiodori, Kurashiki-shi, Okayama Mitsubishi Chemical Corporation Mizushima Works F-term (reference) 5H022 AA04 AA09 AA19 BB06 KK01 5H029 AJ11 AK02 AK03 AK05 AL07 AL08 AM03 AM05 AM07 BJ04 BJ12 CJ03 CJ04 DJ09

Claims (7)

[Claims] 1. A secondary battery in which a battery element in which a positive electrode material and a negative electrode material are laminated via a non-fluid electrolyte layer containing an ionic metal salt is provided. A flat laminated secondary battery characterized in that a portion is formed. 2. The flat plate type secondary battery according to claim 1, wherein the opening is formed by a through hole vertically penetrating the center of the battery element. 3. The flat secondary battery according to claim 1, wherein the opening is formed by a notch extending from the edge of the battery element toward the center. 4. The secondary battery according to claim 1, wherein a fastening material is inserted through the opening to apply a force for vertically pressing the battery element. 5. The secondary battery according to claim 1, wherein a support member is inserted into the opening, and an external force is supported by the support member. 6. The secondary battery according to claim 1, wherein a protective element that suppresses a current when the temperature rises is provided in the opening. 7. The flat laminated secondary battery according to claim 1, wherein the ionic metal salt is a lithium salt.