JP2016110959A - Secondary battery, electric vehicle, power storage system, and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery and the like, capable of preventing ignition and abnormal heat generation of the battery by preventing a thermal runaway even when the battery is used at high temperature or overcharged.SOLUTION: A film outer package battery (50) comprises: an electric element (20); an outer package (10) which houses the electric element together with an electrolytic solution; a positive electrode tab (21) extending from the outer package; a negative electrode tab (25) extending from the outer package; a first conductor (77) connected to the positive electrode tab; a second conductor (78) connected to the negative electrode tab; and an insulator (71) in which a part thereof is fixed to the outer package and the other part thereof is interposed between the first conductor (77) and the second conductor (78).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a secondary battery and the like, and in particular, a secondary battery that can safely stop operation by preventing thermal runaway of the battery even when the battery is used at high temperature or overcharged. It relates to batteries.

  In recent years, batteries used as power sources for electronic devices and automobiles have been strongly required to be smaller and lighter, and there are many batteries that use laminate films instead of conventional metal cans for battery outer bodies. It has become to. As a laminate film, a film using aluminum as a metal thin film, nylon as a battery outer surface as a heat-welding resin film, and polyethylene or polypropylene as an inner surface is generally used. A film-clad battery is one in which a battery element is housed together with an electrolyte in an exterior body (also referred to as a “film exterior body”) made of such a laminate film. Positive and negative electrode tabs are drawn from the battery element, and each electrode tab is configured to extend to the outside of the film outer package.

  By the way, as a general problem of the battery, the internal state of the battery becomes unstable due to use under a high temperature condition or overcharge of the battery, gas is generated, or battery element (especially positive electrode in the case of a lithium ion battery). May run out of heat. These may eventually lead to explosions and fires, and sufficient safety measures must be taken.

  In this regard, for example, in Patent Document 1, a film-covered battery is housed in a hard plastic outer case, and when the film-covered battery expands at an abnormal time, the switch disposed in the outer case is physically moved by the expansion. A configuration for switching the energized state by being pushed by is disclosed.

JP 2001-229893 A

  As described in Patent Document 1, it is also useful to prevent damage to the battery, damage to the circuit, etc. by changing the energization state of the switch and switching the connection state of the electric circuit to which the battery is connected. It is also very important from the viewpoint of safety to prevent the occurrence of battery thermal runaway and to prevent the battery from firing. Such a problem is not unique to the film-clad battery, and can occur in other types of secondary batteries as well.

  The present invention has been made in view of these points, and the purpose of the present invention is to prevent battery thermal runaway even when the battery is used at a high temperature or overcharge. An object of the present invention is to provide a secondary battery or the like that can be stopped in operation.

In order to achieve the above object, a secondary battery according to an embodiment of the present invention is as follows:
Electrical elements,
An exterior body that houses the electrical element together with the electrolyte;
A positive electrode tab extending from the exterior body;
A negative electrode tab extending from the exterior body;
A first conductor connected to the positive electrode tab;
A second conductor connected to the negative electrode tab;
An insulator in which a part is fixed to the exterior body and the other part is interposed between the first conductor and the second conductor;
A secondary battery comprising:

(Explanation of terms)
The “secondary battery” includes not only those using a film outer package such as a laminate film (film outer battery) but also those using a hard container such as a metal can or a resin case as the outer package.
“Film-clad battery” refers to a battery in which a battery element is housed in a film-clad body together with an electrolyte. An example is a flat shape as a whole. For example, a battery for an electric vehicle is required to have a large capacity, a low internal resistance, a high heat dissipation, and the like, and a film-covered battery is advantageous in these respects. One film-clad battery may be referred to as a “battery cell” or simply a “cell”.
The “film outer package” means an outer package made of a flexible film and containing a battery element. The film element is hermetically sealed by arranging two films facing each other and welding them together. Alternatively, the battery element may be sealed by folding a single film and welding the opposed surfaces.

  According to the present invention, it is possible to provide a secondary battery or the like that can safely stop operation of a battery by preventing thermal runaway of the battery even when the battery is used at a high temperature or overcharged. Can do.

It is a perspective view of the film-clad battery of 1st Embodiment. It is sectional drawing which shows a part of cross section of the battery of FIG. It is a schematic diagram for demonstrating operation | movement of the safety mechanism of the battery of FIG. It is a schematic diagram which shows the film-clad battery of another example. It is a schematic diagram which shows the film-clad battery of another example. It is a figure for demonstrating the additional element of a film-clad battery. It is a figure for demonstrating the additional element of a film-clad battery. It is a figure which shows the film-clad battery of another example. It is a figure which shows the film-clad battery of a 2nd form. It is a figure which shows the film-clad battery of a 3rd form. It is a figure which shows the film-clad battery of a 4th form. It is a schematic diagram of an electrical storage system. It is a schematic diagram of an electric vehicle.

1. Basic configuration of film-clad battery (1-1. Basic configuration)
The basic configuration of the film-clad battery will be briefly described first with reference to FIGS. The film-clad battery of this embodiment is characterized by having a safety mechanism 70 (details will be described later). However, for convenience of explanation, only the basic configuration of the battery is shown in FIG. The mechanism is not shown.

  As shown in FIGS. 1 and 2, a film-clad battery 50 according to an embodiment of the present invention includes a battery element 20, a film-clad body 10, a positive electrode tab 21, and a negative electrode tab 25 (hereinafter simply referred to as “electrode tab”. ")".

  The battery element 20 is formed by alternately laminating a plurality of positive electrodes and a plurality of negative electrodes made of metal foils each coated with an electrode material on both sides of a separator. Although the overall external shape of the battery element 20 is not particularly limited, in this example, it is a flat and substantially rectangular parallelepiped. Although detailed illustration is omitted, each of the positive electrode and the negative electrode has an extended portion that partially protrudes from a part of the outer periphery. The extension part of the positive electrode and the extension part of the negative electrode are alternately arranged so as not to interfere with each other when the positive electrode and the negative electrode are stacked. All the negative electrode extensions are collected together and connected to the negative electrode tab. Similarly, for the positive electrode, all the positive electrode extensions are collected together and connected to the positive electrode tab. The connection between the electrode tab and the extension may be made by welding.

(1-2. About each element)
For each element of the battery element, specifically, the following may be adopted.
<Separator>
As separators, webs and sheets made of organic materials, for example, woven fabrics such as polyimide, polyamide, and cellulose, nonwoven fabrics, polyolefins such as polyethylene and polypropylene, porous polymer films such as polyamide, polyimide, and porous polyvinylidene fluoride films Alternatively, an ion conductive polymer electrolyte membrane or the like can be used. These can be used alone or in combination.

Moreover, the separator which consists of inorganic materials, such as a ceramic and glass, can also be used as a separator. As an inorganic separator, a nonwoven fabric separator made of ceramic short fibers such as alumina, alumina-silica, potassium titanate, or a base material made of a woven fabric, a nonwoven fabric, paper, or a porous film, a heat-resistant nitrogen-containing aromatic polymer, and A separator comprising a layer containing ceramic powder, or a heat resistant layer is provided on a part of the surface, and this heat resistant layer is a porous thin film layer containing ceramic powder, a porous thin film layer of a heat resistant resin, or Porous thin film layer separator made of a composite of ceramic powder and heat-resistant resin, or porous made by binding secondary particles formed by sintering or dissolving and recrystallizing a part of primary particles of a ceramic material by a binder A separator provided with a membrane layer or a base material layer made of a polyolefin porous membrane, and formed on one or both sides of the base material layer The heat-resistant insulating layer includes a separator containing oxidation-resistant ceramic particles and a heat-resistant resin, or a porous film formed by combining a ceramic substance and a binder, Silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), nitride of silicon (Si), hydroxide of aluminum (Al), zirconium (Zr ) Alkoxide, a separator using a titanium (Ti) ketone compound, or a polymer substrate, and Al ₂ O ₃ , MgO, TiO ₂ , Al (OH) ₃ , Mg ( Examples thereof include a separator including a ceramic-containing coating layer of OH) ₂ and Ti (OH) ₄ .

<Negative electrode>
The negative electrode has a negative electrode current collector formed of a metal foil, and a negative electrode active material coated on both surfaces of the negative electrode current collector. The negative electrode active material is bound so as to cover the negative electrode current collector with a negative electrode binder. The negative electrode current collector is formed to have an extension connected to the negative electrode terminal, and the negative electrode active material is not applied to the extension.

  The negative electrode active material in the present embodiment is not particularly limited. For example, a carbon material that can occlude and release lithium ions, a metal that can be alloyed with lithium, a metal oxide that can occlude and release lithium ions, and the like. Is mentioned.

  Examples of the carbon material include carbon, amorphous carbon, diamond-like carbon, carbon nanotube, or a composite thereof. Here, carbon with high crystallinity has high electrical conductivity, and is excellent in adhesiveness and voltage flatness with a negative electrode current collector made of a metal such as copper. On the other hand, since amorphous carbon having low crystallinity has a relatively small volume expansion, it has a high effect of relaxing the volume expansion of the entire negative electrode, and deterioration due to non-uniformity such as crystal grain boundaries and defects hardly occurs.

  A negative electrode containing a metal or metal oxide is preferable in that the energy density can be improved and the capacity per unit weight or unit volume of the battery can be increased.

  Examples of the metal include Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, or alloys of two or more thereof. Moreover, you may use these metals or alloys in mixture of 2 or more types. These metals or alloys may contain one or more non-metallic elements.

  Examples of the metal oxide include silicon oxide, aluminum oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, and composites thereof. In this embodiment, it is preferable that tin oxide or silicon oxide is included as a negative electrode active material, and it is more preferable that silicon oxide is included. This is because silicon oxide is relatively stable and hardly causes a reaction with other compounds. Moreover, 0.1-5 mass% of 1 type, or 2 or more types of elements chosen from nitrogen, boron, and sulfur can also be added to a metal oxide, for example. By carrying out like this, the electrical conductivity of a metal oxide can be improved.

  Further, the negative electrode active material can be used by mixing a plurality of materials without using a single material. For example, the same kind of materials such as graphite and amorphous carbon may be mixed, or different kinds of materials such as graphite and silicon may be mixed.

  The binder for the negative electrode is not particularly limited. For example, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer. Rubber, polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamideimide, polyacrylic acid, or the like can be used. The amount of the binder for the negative electrode used is 0.5 to 25 parts by mass with respect to 100 parts by mass of the negative electrode active material from the viewpoints of “sufficient binding force” and “higher energy” which are in a trade-off relationship. Is preferred.

  As the negative electrode current collector, aluminum, nickel, stainless steel, chromium, copper, silver, and alloys thereof are preferable from the viewpoint of electrochemical stability. Examples of the shape include foil, flat plate, and mesh.

<Positive electrode>
The positive electrode has a positive electrode current collector formed of a metal foil, and a positive electrode active material coated on both surfaces of the positive electrode current collector. The positive electrode active material is bound so as to cover the positive electrode current collector with a positive electrode binder. The positive electrode current collector is formed to have an extension connected to the positive electrode terminal, and the positive electrode active material is not applied to the extension.

The positive electrode active material has a layered structure such as LiMnO ₂ , LixMn ₂ O ₄ (0 <x <2), Li ₂ MnO ₃ , Li _x Mn _1.5 Ni _0.5 O ₄ (0 <x <2). Lithium manganate or lithium manganate having a spinel structure, LiCoO ₂ , LiNiO ₂ or a part of these transition metals replaced with other metals, LiNi _1/3 Co _1/3 Mn _1/3 O _2, etc. Lithium transition metal oxides whose specific transition metals are less than half, those in which these lithium transition metal oxides have an excess of Li over the stoichiometric composition, those having an olivine structure such as LiFePO ₄ , etc. It is done. Further, these metal oxides were partially substituted with Al, Fe, P, Ti, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, etc. Materials can also be used. In particular, Li _α Ni _β Co _γ Al _δ O ₂ (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.7, γ ≦ 0.2) or Li _α Ni _β Co _γ Mn _δ O ₂ (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.6, γ ≦ 0.2) are preferable. A positive electrode active material can be used individually by 1 type or in combination of 2 or more types.

  A radical material or the like can also be used as the positive electrode active material.

  As the positive electrode binder, the same binder as the negative electrode binder can be used. The amount of the binder for the positive electrode to be used is preferably 2 to 15 parts by mass with respect to 100 parts by mass of the positive electrode active material from the viewpoints of “sufficient binding force” and “high energy” in a trade-off relationship. .

  As the positive electrode current collector, for example, aluminum, nickel, silver, or an alloy thereof can be used. Examples of the shape of the positive electrode current collector include a foil, a flat plate, and a mesh. As the positive electrode current collector, an aluminum foil can be suitably used.

  A conductive auxiliary material may be added to the coating layer of the positive electrode active material for the purpose of reducing impedance. Examples of the conductive auxiliary material include carbonaceous fine particles such as graphite, carbon black, and acetylene black.

<Electrolyte>
As the electrolytic solution used in the present embodiment, a nonaqueous electrolytic solution containing a lithium salt (supporting salt) and a nonaqueous solvent that dissolves the supporting salt can be used. Specifically, a low boiling point solvent such as a chain carbonate or a chain carboxylic acid ester is preferable. As the additive, an agent that gasifies using the positive electrode reaching a predetermined potential as a trigger may be used. Specifically, a compound (such as cyclohexylbenzene or biphenyl) that is oxidized at a potential about 0.1 to 2 V higher than the potential reached by the positive electrode during normal use to generate a gas can be used.

  As the non-aqueous solvent, an aprotic organic solvent such as a carbonic acid ester (chain or cyclic carbonate), a carboxylic acid ester (chain or cyclic carboxylic acid ester), or a phosphoric acid ester can be used.

  Examples of carbonate solvents include cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC); dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate. (EMC), chain carbonates such as dipropyl carbonate (DPC); and propylene carbonate derivatives.

  Examples of the carboxylic acid ester solvent include aliphatic carboxylic acid esters such as methyl formate, methyl acetate, and ethyl propionate; and lactones such as γ-butyrolactone.

  Among these, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (MEC), dipropyl carbonate Carbonic acid esters (cyclic or chain carbonates) such as (DPC) are preferred.

  Examples of the phosphate ester include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, trioctyl phosphate, and triphenyl phosphate.

  Other solvents that can be contained in the non-aqueous electrolyte include, for example, ethylene sulfite (ES), propane sultone (PS), butane sultone (BS), dioxathilane-2,2-dioxide (DD), and sulfolene. 3-methylsulfolene, sulfolane (SL), succinic anhydride (SUCAH), propionic anhydride, acetic anhydride, maleic anhydride, diallyl carbonate (DAC), dimethyl 2,5-dioxahexanoate, 2,5 Dimethyl hexane hexanoate, furan, 2,5-dimethylfuran, diphenyl disulfide (DPS), dimethoxyethane (DME), dimethoxymethane (DMM), diethoxyethane (DEE), ethoxymethoxyethane, chloroethylene carbonate , Dimethyl ether, methyl ether Ether, methyl propyl ether, ethyl propyl ether, dipropyl ether, methyl butyl ether, diethyl ether, phenyl methyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), tetrahydropyran (THP), 1,4-dioxane (DIOX), 1,3-dioxolane (DOL), methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methyl difluoroacetate, methyl propionate, ethyl propionate, propyl propionate, methyl formate , Ethyl formate, ethyl butyrate, isopropyl butyrate, methyl isobutyrate, methyl cyanoacetate, vinyl acetate, diphenyl Disulfide, dimethyl sulfide, diethyl sulfide, adiponitrile, valeronitrile, glutaronitrile, malononitrile, succinonitrile, pimonitrile, suberonitrile, isobutyronitrile, biphenyl, thiophene, methyl ethyl ketone, fluorobenzene, hexafluorobenzene, carbonate electrolyte, glyme , Ether, acetonitrile, propiononitrile, γ-butyrolactone, γ-valerolactone, dimethyl sulfoxide (DMSO) ionic liquid, phosphazene, methyl formate, methyl acetate, ethyl propionate and other aliphatic carboxylic acid esters, or these compounds In which a part of the hydrogen atoms are substituted with fluorine atoms.

As the supporting salt in the present embodiment, LiPF ₆ , LiAsF ₆ , LiAlCl ₄ , LiClO ₄ , LiBF ₄ , LiSbF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiN ( CF ₃ SO _{2) 2} normal lithium salt which can be used in lithium ion batteries or the like can be used. The supporting salt can be used alone or in combination of two or more.

  A non-aqueous solvent can be used individually by 1 type or in combination of 2 or more types.

<Exterior body>
The exterior body can be appropriately selected as long as it is stable to the electrolytic solution and has a sufficient water vapor barrier property. For example, in the case of a laminated laminate type secondary battery, it is preferable to use a laminate film of aluminum and resin as the outer package. An exterior body may be comprised with a single member and may be comprised combining several members.

2. Next, specific examples of the film-clad battery according to the present invention will be specifically described. In the following, the first to fourth embodiments will be described in the following order:
-First configuration-two examples of conductors connecting between electrode tabs-Second configuration-one example of conductor connecting between electrode tabs-Third configuration-energization of electrode tabs is cut off when gas is generated Example 4th-Example in which energization interruption and short-circuiting of electrode tab are performed simultaneously when gas is generated

(2-1. First embodiment)
In this embodiment, as shown in FIG. 1, the film outer package 10 may be composed of a first film 11 and a second film 12 disposed to face the first film 11. The outline shape of the film outer package 10 is not particularly limited, but may be a quadrangle, which is a rectangle in this example. Both the films 11 and 12 are heat-welded to each other around the battery element 20 and joined. Thereby, the peripheral part of the film exterior body 10 becomes the heat welding part 15. A positive electrode tab 21 and a negative electrode tab 25 are drawn from one side of the short side of the heat-welded portion 15. In one embodiment, the positive electrode tab 21 and the negative electrode tab 25 are preferably parallel, but the present invention is not limited to this. In the following description, the positive electrode tab 21 and the negative electrode tab 25 are also simply referred to as electrode tabs without distinction.

  In addition, about the extraction position of an electrode tab, the tab may be pulled out from one side of the long side. One electrode tab and the other electrode tab may be pulled out from different sides. As an example of this, there is a configuration in which one electrode tab and the other electrode tab are drawn out in opposite directions from sides facing each other.

(Safety mechanism)
In the film-clad battery 50 of the present embodiment, a safety mechanism 70 is provided. The safety mechanism 70 includes a first conductor 77 partially connected to the positive electrode tab 21, a second conductor 78 partially connected to the negative electrode tab 25, and a part of the film outer package. 10 and an insulator 71 fixed to the outer surface. For fixing the conductors 77 and 78 to the electrode tabs, for example, electrical and physical connection such as resistance welding, ultrasonic welding, laser welding, caulking, and adhesion using a conductive adhesive can be employed. .

  The safety mechanism 70 plays a role of electrically connecting the electrode tabs 21 and 25 to release the energy of the cell when the film outer package 10 expands beyond a predetermined level.

  Although the outline shape of the first conductor 77 is not particularly limited, in this example, it is formed as an elongated strip-shaped metal piece. The first conductor 77 is connected to a part of the positive electrode tab 21 at the base end side and extends toward the negative electrode tab 25. In this example, the first conductor 77 terminates in the vicinity of a substantially intermediate position between the positive electrode tab 21 and the negative electrode tab 25 as an example. As a material of the conductor, any material can be used as long as it is conductive. Specifically, copper, silver, aluminum, alloys thereof, and the like can be used. The thickness of the conductor may be, for example, about 0.1 mm to 1 mm. The shape of the conductor can be changed as appropriate, and may be, for example, a sheet shape, a strip shape, a plate shape, a rod shape, a line shape, or the like.

  The shape and material of the second conductor 78 may be the same as that of the first conductor 77. However, the present invention is not limited to this, and may have different shapes and / or materials. The second conductor 78 has a proximal end connected to a part of the negative electrode tab 25 and extends toward the positive electrode tab 21. In this example, the second conductor 78 is also terminated in the vicinity of a substantially intermediate position between the positive electrode tab and the negative electrode tab as an example. The conductors 77 and 78 have such a length that their tips partially overlap each other.

  FIG. 1 depicts a configuration in which the extending direction of the conductors 77, 78 is orthogonal or substantially orthogonal to the extending direction of the electrode tabs 21, 25. As long as 77 and 78 partially overlap each other, it can be appropriately changed.

  It is preferable that a resistance member is provided in at least one of the first conductor 77 and the second conductor 78, or between both the conductors. In the example of FIG. 1, an example in which a resistance member 75 is provided on a part of the first conductor 77 is shown. As will be described later, the conductors 77 and 78 are members that are electrically insulated in a normal state and are electrically connected to each other in order to release the energy of the cell in an abnormal state. This is because by providing the resistance member 75 in this manner, the electric energy of the cell is released as heat energy, and the thermal runaway of the battery element can be avoided more reliably. The resistance member may be either metallic or nonmetallic.

  In this example, the insulator 71 is formed as an elongated strip-shaped insulating material. As a material of the insulator, for example, an insulating material such as paper or sheet-like resin can be used. The insulator 71 may have any shape as long as it moves when triggered by the expansion of the film outer package 10. The insulator 71 is preferably flexible, but in some embodiments, a non-flexible one can be used. In the case of the insulator 71 having flexibility, the insulator 71 is preferable in that it can satisfactorily follow the expansion and deformation of the film outer package 10.

  One end of the insulator 71 may be fixed to a part of the film outer package 10, and the other end may be a free end. As will be described later, the insulator 71 is pulled when the film exterior body expands, and its free end moves. Therefore, the length of the insulator 71 needs to be long to some extent so that the amount of movement of the free end is sufficient. For example, it may be 10% or more, 25% or more, or 50% or more of the length of the long side of the film outer package 10.

  As an example, the melting point of the insulator is preferably 100 ° C. or higher, more preferably 130 ° C. or higher, and further preferably 180 ° C. or higher. In the case where the melting point of the insulator is lower than the above temperature, there is a possibility that the insulator contracts, softens or dissolves at the time of charge / discharge at the current density used normally or at a high temperature, and the conductors come into contact with each other.

  The free end side of the insulator 71 extends to a region between the electrode tabs 21 and 25 (see FIG. 1), and its tip is sandwiched between the first and second conductors 77 and 78. ing. This prevents electrical connection between the conductors 77 and 78 (and thus electrical connection between the electrode tabs).

(Operation)
In the film-covered battery 50 of the present embodiment configured as described above, when gas is generated in the battery due to use under high temperature conditions, overcharge, or the like, as shown in FIG. 10 expands, and the insulator 71 is gradually pulled and moved accordingly. In FIG. 3A, since the insulator 71 is present between the conductors 77 and 78, the electrical connection between both members is prevented. However, when the expansion exceeds a predetermined value, the insulator shown in FIG. Thus, the tip of the insulator 71 is disengaged from between the conductors 77 and 78. Thereby, the conductors 77 and 78 contact and the electrode tabs 21 and 25 are electrically short-circuited.

  According to the film-clad battery 50 of the present embodiment configured as described above, gas is generated in the battery at the time of abnormality, and the film-clad body 10 expands beyond a predetermined level, so that the tip of the insulator 71 is initially held. The electrode tabs are short-circuited. Then, the electric energy of the cell is released as heat energy in the resistance member 75. As a result, the battery element can be prevented from thermal runaway and progress, and the battery can be safely stopped.

  Moreover, since the structure of this embodiment moves the insulator 71 by expansion | swelling of the film exterior body 10, it does not require the special mechanism for moving the insulator 71, and is implement | achieved by a simple structure. be able to. According to such a simple structure, the number of members can be reduced, which is advantageous in suppressing the manufacturing cost, and is also preferable in terms of weight energy density and volume energy density.

  In addition, in the case of the configuration using the insulator 71 and the conductors 77 and 78 illustrated in FIG. 1, since it can be configured with any thin member, it is advantageous in that the battery cell can be kept small and light. However, in a battery for applications where the size and weight of the battery cell do not matter so much, there is no need to be constrained by the thickness, size, weight, etc. of the insulator 71 and the conductors 77 and 78.

While the present invention has been described with reference to specific examples of the battery, the present invention can be modified without departing from the spirit thereof and various configurations can be adopted.
(A1) Regarding the exterior body, the following configuration may also be adopted. For example, a container such as a metal can or a resin case can be used as the exterior body as long as it expands by gas generation.
(A2) Regarding the structure near the overlapping portion of the conductors 77 and 78, the following configuration can also be adopted. That is, these conductors 77 and 78 need to contact each other in the state of FIG. Therefore, it is also preferable that the conductors 77 and 78 have a structure in which the conductors 77 and 78 are in close contact with each other. For example, an elastic member such as a spring that biases one conductor toward the other conductor may be used. As another embodiment, a member such as a clip that presses one or both of the conductors 77 and 78 may be used. This will be specifically described later with reference to FIGS. 6A and 6B.

Subsequently, some other examples will be described in order with reference to the drawings.
(Other example 1)
In the film-clad battery 51 of FIG. 4, the film-clad body 10 has the main chamber 10a and the subchamber 10b which were mutually connected, and the battery element 20, electrolyte solution, etc. are accommodated in the main chamber 10a. On the other hand, the sub chamber 10b is a portion that functions as a gas reservoir. For example, the gas generated in the main chamber 10a at the time of abnormality is configured to expand when the gas is accumulated in the sub chamber 10b. . The volume of the sub chamber 10b is an example and is smaller than the main chamber 10a. The communication between the main chamber 10a and the sub chamber 10b is performed, for example, when a pressure in the main chamber rises to a predetermined level or more due to gas generation, a sealing portion (not shown, for example, a weak seal portion) is opened, whereby both chambers communicate. It may be something like this.

  In the case of a film-clad battery, each cell may be housed in a hard case depending on the application and product. In such a case, the main chamber of the film-clad battery (the chamber in which the battery element is accommodated) may not be greatly deformable due to the structure. Moreover, in a certain form, in order to maintain battery performance favorably, a film-clad battery may be arrange | positioned in an apparatus in the state pressed in the thickness direction. In such a case, as shown in FIG. 4, a sub chamber 10b that expands greatly when gas is generated is provided separately from the main chamber 10a, and the insulator 71 moves by utilizing the expansion of the sub chamber 10b. Is also preferable.

  The position of the sub chamber 10b is not particularly limited, but may be between the main chamber 10a and the conductors 77 and 78 (see FIG. 4).

  In the example of FIG. 4, the insulator 71 is fixed to the upper surface (one example) of the main chamber 10 a of the film exterior body 10, and extends to the conductors 77 and 78 through the sub chamber 10 b. When gas is generated in the battery at the time of abnormality, the gas moves from the main chamber 10a to the sub chamber 10b, and the sub chamber 10b expands greatly, thereby the insulator 71 is lifted and pulled. . When the expansion of the sub chamber 10b reaches a predetermined level or more, the tip of the insulator 71 is detached from between the conductors 77 and 78. Thereby, the conductors 77 and 78 abut and the electrode tabs are electrically short-circuited.

  Even with such a configuration, it is possible to obtain the same effect as that of the embodiment described above, in which the electrode tabs are short-circuited to release the electric energy of the cell and the battery is safely stopped.

(Other example 2)
The position where the insulator 71 is attached to the film outer package 10 can also be changed as appropriate. For example, the configuration shown in FIG. In the film-clad battery 52 of FIG. 5, the end portion of the insulator 71 is connected to the heat-welded portion 15 ′ on the periphery of the film-clad body 10.

  In the initial state of the film-clad battery 52, the heat-welded portion 15 ′ may be bent so that the tip side thereof overlaps the film-clad body 10. In the initial state, the insulator 71 connected to the heat welded portion 15 ′ extends across the upper surface of the film exterior body 10, and its tip extends beyond the opposite heat welded portion, It is sandwiched between the conductors 77 and 78.

  When gas is generated in the battery at the time of abnormality, the film outer package 10 expands as in the above embodiment, whereby the heat-welded portion 15 ′ bent on the film outer package 10 tends to extend straight, The insulator 71 is pulled and moved.

  When the insulator 71 is pulled by a predetermined distance, the tip of the insulator 71 is detached from between the conductors 77 and 78, the conductors 77 and 78 come into contact, and the electrode tabs are electrically short-circuited. Even with such a configuration, the electrode tabs can be short-circuited to release the electric energy of the cell, and the battery can be safely stopped.

  Further, as is clear from this example, the fixing position of the end portion of the insulator 71 is not limited to the vicinity of the center portion of the film exterior body 10, and may be the thermal welding portion 15 ′ on the periphery. In still another example, the insulator 71 may be held and fixed to a part other than the film outer package. That is, as long as the distal end of the insulator 71 can be moved when the film exterior body expands, it is not an essential part of the present invention where the insulator 71 is fixed.

(Other example 3)
The basic idea in the above-described embodiment is that the conductors 77 and 78 are normally insulated by the insulator 71, and the insulator 71 moves and the conductors 77 and 78 move when the film exterior body expands more than a certain amount. Are in contact and short-circuited. Here, an urging member (detailed below) for applying an urging force to the conductors 77 and 78 may be used so that the conductors 77 and 78 are more reliably short-circuited.

  The “biasing member” is any member that can apply a biasing force to one or both of the conductors 77 and 78 in such a direction that the conductors 77 and 78 come into contact with each other. Also good. Specifically, a clamping member such as a clip may be used.

  In FIG. 6A, the holding member 80 is schematically drawn, and the conductors 77 and 78 are swallowed. The clamping member 80 has a bent portion 83 that can be elastically deformed and a pair of contact portions 81a and 81b that sandwich the conductor. The clamping member 80 may be provided as a single component, in which a bent portion 83 is formed in a part thereof, and a pair of contact portions 81a and 81b are formed in other portions (for example, Something like a gem clip). The material may be either resin or metal.

  Alternatively, the contact portions 81a and 81b and the bent portion 83 (in other words, a portion for pressing and a portion for generating an urging force) may be configured as separate parts. For example, as shown in FIG. 6B, a pair of contact portions 81a and 81b and an elastic body 83 ′ that presses them may be provided. In FIG. 6B, two elastic bodies 83 ′ are drawn, but only one of them may be provided. The elastic body 83 ′ may be a coil spring or the like, but may also be a leaf spring, for example.

(Operation)
In the state of FIG. 6A (a), the bent portion 83 is elastically deformed in a slightly opened state, and the pair of contact portions 81a and 81b sandwich and press the conductors 77 and 78 by the elastic force. . When the gas is generated and the insulator 71 is pulled, the tip 71 is gradually removed from between the conductors 77 and 78, and finally is completely pulled out as shown in FIG. 6A (b). As a result, the conductors 77 and 78 come into contact with each other, thereby causing a short circuit. Thus, according to the structure using the clamping member 80, the conductors 77 and 78 can be contact | abutted more reliably and the short circuit of electrode tabs can be caused.

(Other example 4)
In the above-described embodiment (FIG. 1A), the conductors 77 and 78 extend straight from the electrode tabs 21 and 25 in the width direction, but the shape may be as shown in FIG.

  In this example, the conductor 77-1 has a portion 77a joined to the electrode tab 21 and a portion 77b overlapping with a part of the counterpart conductor 78-1. As an example, the conductor 77-1 has a shape that does not protrude from the upper surface of the electrode tab 21 and the heat welded portion 15 (in other words, the shape held by the electrode tab 21 and the heat welded portion 15). Shape). For example, the whole may be a substantially L-shaped member.

  The conductor 78-1 also has a portion 78a that is joined to the electrode tab 25 and a portion 78b that overlaps a part of the counterpart conductor 77-1. As an example, like the conductor 77-1, the whole is formed as a substantially L-shaped member.

  In addition, about the material, thickness, etc. of the conductors 77-1, 78-1, the thing similar to the thing of embodiment mentioned above can be utilized.

  According to such a configuration, since the members (21, 25, 15) for holding the conductors 77-1, 78-1 are present, the conductors 77-1, 78-1 are hardly deformed. Contributes to improved handling and ease of manufacture. In particular, since it is held by the electrode tabs 21 and 25 that normally exist as a film-clad battery or a part of the film-clad body 10 (the heat-welded portion 15), a dedicated battery for holding the conductors 21 and 25 is used. There is no need to add additional members.

  In addition, in the example of FIG. 7, you may use together the clip (clamping member) 83 mentioned above. In this case, the clip may be configured to sandwich the three members of the conductor 77-1, the insulator 71, and the conductor 78-1, or the conductor 77-1, the insulator 71, and the conductor 78-1. The four members of the heat welding portion 15 may be sandwiched.

  In addition, although some modified examples have been described above, the characteristic portions of the examples can be appropriately combined and used for the configurations described as other aspects without departing from the gist of the present invention. . For example, the above-described sandwiching member and clip can be used in the configurations of the embodiments of the present specification in order to reliably contact the target conductive members.

(2-2. Second embodiment)
In the first embodiment, two examples of the conductor connecting the electrode tabs have been described, but in the second embodiment, only one conductor connecting the electrode tabs is provided. Examples of such a form include those shown in FIGS. 8A and 8B. The electrode tab to which the conductor is connected may be either a positive electrode tab or a negative electrode tab. Hereinafter, an example in which the electrode tab is fixed to the negative electrode tab 25 will be described.

  In FIG. 8A, the conductor 78 extends to a position where it contacts the positive electrode tab 21. The conductor 78 may have any shape, but in this example, it is an elongated strip. An insulator 71 is interposed between the tip of the conductor 78 and the positive electrode tab 21. As the insulator 71, the thing similar to what was demonstrated by embodiment mentioned above can be used. The same applies to the configuration shown in FIG.

  In FIG. 8B, a conductor 78-1 having a shape extending on the upper surface of the electrode tab or the heat-welded portion as in the example of FIG. 7 is used. The conductor 78-1 has a portion 78a connected to one electrode tab (here, the negative electrode tab 25) and a portion 78b contacting the other electrode tab (here, the positive electrode tab 21). The conductor 78-1 is an example, and may be formed in a substantially U shape as a whole. An insulator 71 is interposed between the positive electrode tab 21 and the tip portion 78 b of the conductor 78.

8 (a) and 8 (b), when the film exterior body expands when the gas is generated, and the insulator 71 is pulled by a predetermined distance, the conductor 71 becomes the conductor 78-1 and the positive electrode. The conductor 78-1 and the positive electrode tab 21 come into contact with each other through the tab 21, thereby causing a short circuit of the electrode tab. Thus, even if it is the structure using only the one conductor 78-1, there can exist an effect similar to the said embodiment.
(2-3. Third embodiment)
The technical idea of one embodiment of the present invention that uses a member that moves when gas is generated can be applied to cut off the energization of the electrode tabs in addition to short-circuiting the electrode tabs. This will be described with reference to FIG.

  FIG. 9 is the same as the embodiment described above with respect to the battery element and the film outer package, but is different in that one of the positive electrode tab 21 and the negative electrode tab 25 (here, the negative electrode tab) is cut. Of the negative electrode tab 25, the one pulled out from the film outer package 10 is defined as a first portion 25-1, and the one disposed with a predetermined gap with respect to the first portion 25-1 is a second portion. Let it be portion 25-2.

  In the form of FIG. 9, a conductor 72 is further provided in contact with and electrically connecting the first portion 25-1 and the second portion 25-2. For example, the conductor 72 may be a sheet having flexibility. In addition, for example, it may be a long and narrow band. The base end portion (not shown in FIG. 9) of the conductor 72 may be fixed at the same mounting position as the insulator 71 described above. In other words, like the insulator 71, the conductor 72 has a specific shape or end as long as it moves (pulled in one example) with the expansion of the film outer package 10 when gas is generated. The attachment position of the part is not particularly limited.

  9 exemplifies the conductor 72 as a whole in FIG. 9, of course, a part of the member 72 on the tip side (at least the first portion 25-1 and the second portion 25-2). Only the range in contact with both of them may be a conductor, and the others may be non-conductive.

  In the configuration of FIG. 9, when the film outer package 10 expands when gas is generated, the conductor 72 is pulled and moved. When the tip of the conductor 72 is separated from the second portion 25-2, the energized state between the first portion 25-1 and the second portion 25-2 is interrupted.

  According to such a configuration, the function as the battery can be lost in the event of an abnormal gas generation, so that further thermal runaway or the like can be prevented, and the battery can be safely stopped.

The conductor 72 in FIG. 9 can also be described as follows. That is, in the initial state, the conductor has (i) a first portion in which the conductive portion is in contact with both the first and second portions of the electrode tab, thereby electrically connecting the first and second portions. (Ii) When the expansion of the film outer package exceeds a predetermined range, the film moves to the second position, and the conductive portion is in contact with both the first and second portions. In this state, the electrical connection between the first and second portions is released.
(2-4. Fourth embodiment)
The technical idea of an embodiment of the present invention that uses a member that moves when gas is generated can be applied to a configuration in which a short circuit between electrode tabs and a disconnection of current between electrode tabs are generated simultaneously. . “Simultaneous” means that the two do not necessarily have to occur exactly at the same time, but may occur at slightly different timings.

  The configuration of FIG. 10 is the same as that of the above-described embodiment with respect to the battery element and the film outer package, and one of the positive electrode tab 21 and the negative electrode degree 25 (here, the negative electrode tab 25) is separated. It is the same as the form. In this configuration, as the member 73 that moves when the gas is generated, the tip 73b is a conductor and the other portion 73a is non-conductive. Further, a conductor 79 such as the conductor 78-1 shown in FIG. 8B is provided. The conductor 79 is an example, and is formed in a substantially U shape as a whole. One end of the conductor 79 is connected to one of the positive electrode tab 21 and the negative electrode tab 25 (here, the positive electrode tab 21), and the other end is a first portion 25-1 that is a part of the negative electrode tab 25. It is located where it touches.

  In the initial state of the battery, the first portion 25-1 and the second portion 25-2 of the electrode tab 25 are electrically connected by contacting the conductive tip 73b of the member 73. On the other hand, a non-conductive portion 73a is interposed between the electrode tab 25 and the conductor 79 to prevent electrical connection between the members.

(Operation)
In the configuration of FIG. 10, when the film exterior body expands when gas is generated, the member 73 is pulled and moved. When the end portion of the conductive tip portion 73b is separated from the second portion 25-2, the energized state between the first portion 25-1 and the second portion 25-2 is interrupted. Further, the tip portion 73b moves between the electrode tab 25 and the conductor 79, whereby the electrode tab 25 and the conductor 79 are electrically connected, thereby causing a short circuit between the electrode tabs. be able to.

  According to such a configuration, it is possible to cause short-circuiting of the electrode tab and interruption of energization at the time of abnormality in which gas is generated, and the battery can be stopped more safely.

  The member 73 in FIG. 10 can also be described as follows. That is, the member is (i) in an initial state, the conductive portion is in contact with both the first and second portions, thereby electrically connecting the first and second portions, and the insulating portion. Is disposed at the first position where the short circuit between the electrode tabs is prevented, while (ii) when the expansion of the film outer body exceeds a predetermined range, the second position (specifically, A position where the conductive portion does not contact both the first and second portions and a position where both the first portion and the conductor end extending from the electrode tab contact). .

(Production method)
The present invention can also be expressed as a method for manufacturing a secondary battery. That is, the manufacturing method according to an aspect of the present invention includes the steps of preparing the battery element 20 and housing the electric element 20 together with the electrolytic solution in the exterior body 10. In addition, regarding the creation of the safety mechanism 70 (FIG. 1) and the like, the method includes a step of connecting the first conductor to one of the electrode tabs and a step of fixing the second conductor to the other.

  In addition, a part of the insulator 71 or the like is fixed to the outer surface (one example) of the exterior body 10, and the other part of the insulator 71 is insulated from the first conductor 77 and the second conductor 78. And a step of interposing between both conductors.

  The structure described as another embodiment can be basically manufactured by the same process.

<About inventions other than batteries>
FIG. 11 is a schematic diagram of a power storage system using a secondary battery according to one embodiment of the present invention. The power storage system 1 is not limited in size, but a power supply unit 1A having at least one secondary battery (for example, a film-clad battery), and a control device that monitors and controls charging / discharging of the power supply unit 1A. 1B. Such a power storage system 1 may be, for example, a backup power source, and may be various types such as for large facilities, offices, and homes.

  FIG. 12 is a schematic diagram of an electric vehicle using a secondary battery according to an embodiment of the present invention. The electric vehicle 2 includes a power supply unit 2A having at least one secondary battery (for example, a film-clad battery 50) and a control device 2B that performs monitoring / control of charging / discharging thereof.

  The secondary battery according to one embodiment of the present invention can be used in, for example, all industrial fields that require a power source. For example, it can be used as a power source for mobile devices such as mobile phones and laptop computers; it can be used as a power source for electric vehicles such as electric cars, hybrid cars, electric bikes, and electric assist bicycles; It can be used as a power source for mediums; it can be used as a power storage system for storing electric power.

(Appendix)
The present invention discloses the following inventions:
1. An electrical element (20);
An exterior body (10) that houses the electrical element together with the electrolyte;
A positive electrode tab (21) extending from the outer package;
A negative electrode tab (25) extending from the exterior body;
A first conductor (77) connected to the positive electrode tab;
A second conductor (78) connected to the negative electrode tab;
An insulator (71) partly fixed to the exterior body and the other part interposed between the first conductor (77) and the second conductor (78);
A secondary battery comprising:

  The “insulator” here means the following member in one form. In other words, the term “insulator” as used herein refers to a material that moves when pulled by an expansion of a film outer package or the like (an example only) and induces contact between conductors by the movement. It is. In other words, it does not induce contact between conductors by itself contracting, softening, melting, etc. at a high temperature in a state where an external force such as expansion of the film outer package or the like is not applied.

2. The first conductor and the second conductor overlap each other at the portion where the first conductor and the second conductor are insulated by the insulator.

3. When the insulator moves by a predetermined distance, the conductors come into contact with each other.

4). The insulator is configured to move when the exterior body expands.

5. A resistor is further connected in series to at least one of the first and second conductors.

6). The insulator is a sheet-like member.

7). The exterior body is a film exterior body.

8). An electrical element (20);
An exterior body (10) that houses the electrical element together with the electrolyte;
A positive electrode tab (21) extending from the outer package;
A negative electrode tab (25) extending from the exterior body;
A conductor (78-1) connected to one of the positive electrode tab or the negative electrode tab;
An insulator (71) interposed between a part of the conductor and the other of the positive electrode tab or the negative electrode tab;
A secondary battery comprising:

9. An electrical element (20);
An exterior body (10) that houses the electrical element together with the electrolyte;
A positive electrode tab (21) extending from the outer package;
A negative electrode tab (25) extending from the exterior body;
With
The positive electrode tab or the negative electrode tab has a first portion (25-1) and a second portion (25-2) that are not electrically connected to each other,
further,
A conductor (72) having at least a conductive portion in contact with the first portion (25-1) and the second portion (25-2);
A secondary battery comprising:

10. An electrical element (20);
An exterior body (10) that houses the electrical element together with the electrolyte;
A positive electrode tab (21) extending from the outer package;
A negative electrode tab (25) extending from the exterior body;
A conductor (79) connected to one of the positive electrode tab or the negative electrode tab;
With
The positive electrode tab or the negative electrode tab has a first portion (25-1) and a second portion (25-2) that are not electrically connected to each other,
further,
A conductive portion (73b) in contact with the first portion (25-1) and the second portion (25-2), a part of the conductor, and the other of the positive electrode tab or the negative electrode tab; A secondary battery comprising a member (73) having an insulating portion (73a) interposed therebetween.

  The above 2. ~ 7. As a matter of course, the technical items described in (1) (and various technical items disclosed in the above-described embodiment and the like) are described in 8. -10. It can combine with the invention which concerns on one form of this invention expressed as.

1 Power storage system (power storage equipment)
2 Electric vehicle 10 Film exterior 15, 15 ′ Heat welding portion 10 a Main chamber 10 b Sub chamber 11, 12 Film 15 Thermal welding portion 20 Battery elements 21, 25, 25-1, 25-2 Electrode tabs 50, 51, 52 Film Exterior battery 70 Safety mechanism 71 Insulator 72 Conductor 75 Resistance members 77, 78, 78-1, 79 Conductor 80 Nipping members 81a, 81b Abutting portion 83 Bending portion 83 'Elastic body

Claims (12)

Electrical elements,
An exterior body that houses the electrical element together with the electrolyte;
A positive electrode tab extending from the exterior body;
A negative electrode tab extending from the exterior body;
A first conductor connected to the positive electrode tab;
A second conductor connected to the negative electrode tab;
An insulator in which a part is fixed to the exterior body and the other part is interposed between the first conductor and the second conductor;
A secondary battery comprising:   The second conductor according to claim 1, wherein the first conductor and the second conductor overlap each other at a portion where the first conductor and the second conductor are insulated by the insulator. Next battery.   The secondary battery according to claim 1, wherein the conductors come into contact with each other when the insulator moves by a predetermined distance.   The secondary battery as described in any one of Claims 1-3 comprised so that the said insulator may move, if the said exterior body expand | swells.   The secondary battery according to claim 1, further comprising a resistor connected in series to at least one of the first and second conductors.   The secondary battery as described in any one of Claims 1-5 whose said insulator is a sheet-like member.   The secondary battery as described in any one of Claims 1-6 whose said exterior body is a film exterior body. Electrical elements,
An exterior body that houses the electrical element together with the electrolyte;
A positive electrode tab extending from the exterior body;
A negative electrode tab extending from the exterior body;
A conductor connected to one of the positive electrode tab or the negative electrode tab;
An insulator interposed between a part of the conductor and the other of the positive electrode tab or the negative electrode tab;
A secondary battery comprising: Electrical elements,
An exterior body that houses the electrical element together with the electrolyte;
A positive electrode tab extending from the exterior body;
A negative electrode tab extending from the exterior body;
With
The positive electrode tab or the negative electrode tab has a first portion and a second portion that are not electrically connected to each other,
A secondary battery comprising a conductor having at least a conductive portion in contact with a first portion and a second portion. Electrical elements,
An exterior body that houses the electrical element together with the electrolyte;
A positive electrode tab extending from the exterior body;
A negative electrode tab extending from the exterior body;
A conductor connected to one of the positive electrode tab or the negative electrode tab;
With
The positive electrode tab or the negative electrode tab has a first portion and a second portion that are not electrically connected to each other,
A conductive part in contact with the first part and the second part, and a member having an insulating part interposed between a part of the conductor and the other of the positive electrode tab or the negative electrode tab, Secondary battery.   The electric vehicle which has a secondary battery as described in any one of Claims 1-10.   The electrical storage system which has a secondary battery as described in any one of Claims 1-10.

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