JP2023131247A - Power storage device and manufacturing method for power storage device - Google Patents

Abstract

To further increase the rigidity of a power storage device including a columnar electrode surrounded by a separation membrane.SOLUTION: A power storage device includes a columnar electrode, a counter electrode, and a separation membrane. The power storage device also includes a sheet-like first conductive part provided on the counter electrode along an X-axis direction and a sheet-like second conductive part provided on the counter electrode along a Y-axis direction, where a Z axis is an axial direction of the columnar electrode; an X axis is along a plane perpendicular to the Z axis, and a Y axis is perpendicular to the Z axis. The following formula (1) and/or the following formula (2) is satisfied. 0.5≤Ey/Ex≤2.0...Formula (1) 0.5≤Σ(tn,y*Ln,y3)/Σ(tm,x*Lm,x3)≤2.0...Formula (2) In the formulas, Ex and Ey represent a flexural modulus of elasticity obtained by applying a load along the x-axis direction and a flexural modulus of elasticity obtained by applying a load along the y-axis direction, respectively; Lx, tx, and m represent the length, the thickness and the number of the first conductive part, respectively; and Ly, ty, and n represent the length, the thickness and the number of the second conductive part, respectively.SELECTED DRAWING: Figure 1

Description

This specification discloses a power storage device and a method for manufacturing the power storage device.

Conventionally, secondary batteries with high energy density, which are power storage devices, have been constructed using multiple columnar electrodes, a separation membrane surrounding each columnar electrode, and a separation membrane that fills the space between adjacent separation membranes. A device including a positive electrode has been proposed (see, for example, Patent Document 1). This secondary battery has a structure in which a columnar electrode surrounded by a separation membrane is placed inside a positive electrode. The positive electrode of this secondary battery is obtained by space-filling a columnar positive electrode made of regular hexagonal columns, and the columnar electrode surrounded by a separation membrane is arranged in the center hole of the columnar positive electrode. In addition, a fibrous first electrode containing an active material, a second electrode containing an active material existing between the plurality of fibrous first electrodes, and having ion conductivity and covering the first electrode. a separation membrane that insulates the first electrode and the second electrode, the plurality of fibrous first electrodes are arranged in a predetermined direction, and the diameter D of the first electrode and the thickness L of the separation membrane are A structure having a ratio D/L of 3.3 or more has been proposed (for example, see Patent Document 2).

Japanese Patent Application Publication No. 2018-152229 JP 2019-160733 Publication

By the way, fiber batteries equipped with columnar electrodes such as those disclosed in Patent Documents 1 and 2 are unique lithium batteries that are unrestricted and can be formed into elongated shapes, and have ripple effects such as improved product design. is expected. When considering application to a variety of applications, it is assumed that mechanical loads such as bending stress may be applied to the electricity storage device itself, so it is necessary to ensure mechanical strength, especially bending strength and rigidity, in addition to charging and discharging performance. has become necessary.

The present disclosure has been made in view of such problems, and provides an electricity storage device and a method for manufacturing an electricity storage device that can further increase rigidity in an electricity storage device having a columnar electrode surrounded by a separation membrane. The main purpose is to

As a result of intensive research to achieve the above-mentioned objective, the present inventors discovered that the rigidity of the electricity storage device can be further increased by devising the arrangement direction of the conductive sheet that collects current from the counter electrode facing the columnar electrode. This discovery led to the completion of the invention disclosed herein.

That is, the electricity storage device disclosed in this specification is
a plurality of columnar electrodes containing an electrode active material;
a counter electrode containing a counter electrode active material and existing between the columnar electrodes;
a separation membrane interposed between the columnar electrode and the counter electrode and having insulation and ion conductivity;
When the axial direction of the columnar electrode is the Z-axis, the X-axis along the plane perpendicular to the Z-axis, and the Y-axis perpendicular to the X-axis, a sheet-like first a conductive part;
a sheet-shaped second conductive part provided on the counter electrode along the Y-axis direction,
The bending elastic modulus E _x obtained by applying a load along the X-axis direction, the bending elastic modulus E _y obtained by applying a load along the Y-axis direction, and the length L of the first conductive part. _x , thickness t _x and quantity m, length L _y of the second conductive part, thickness _ty and quantity n,
Either the ratio E _y /E _x of the bending elastic modulus in the X-axis/Y-axis direction satisfies the following formula (1), or the ratio of the sum of the first conductive part and the second conductive part satisfies the following formula (2). satisfies or at least one of
Electricity storage device.
0.5≦E _y /E _x ≦2.0…Formula (1)
0.5≦Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _m,x ³ )≦2.0 …Formula (2)

The method for manufacturing an electricity storage device of the present disclosure includes:
A plurality of columnar electrodes containing an electrode active material, a counter electrode containing a counter electrode active material and existing between the columnar electrodes, and a separation interposed between the columnar electrode and the counter electrode and having insulation and ionic conductivity. A method for manufacturing an electricity storage device comprising a membrane,
A first array body is obtained by arranging unit cells each including the columnar electrode, the counter electrode, and the separation membrane on a sheet-like first conductive part, and then the first array body is laminated to form a first laminated part. The single cells are arranged on a sheet-like second conductive part to obtain a second array, and then the second array is placed on the first laminate in a direction perpendicular to the first array. A lamination step of laminating the
In the lamination step, when the axial direction of the columnar electrode is the Z-axis, the X-axis along the plane perpendicular to the Z-axis, and the Y-axis perpendicular to the X-axis, the direction along which the first conductive part follows is the X-axis direction. The direction along the second conductive part is the Y-axis direction, and the bending elastic modulus E _x obtained by applying a load along the X-axis direction, and the bending elasticity obtained by applying a load along the Y-axis direction. When the ratio E _y is the length L _x , the thickness t _x and the quantity m of the first conductive part, and the length L _y , the thickness t _y and the quantity n of the second conductive part, the X axis/Y Whether the ratio of bending elastic modulus in the axial direction E _y /E _x satisfies the following formula (1) or whether the ratio of the sum of the first conductive part and the second conductive part satisfies the following formula (2). configure to be at least one,
A method for manufacturing a power storage device.
0.5≦E _y /E _x ≦2.0…Formula (1)
0.5≦Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _m,x ³ )≦2.0 …Formula (2)

Alternatively, the method for manufacturing an electricity storage device of the present disclosure includes:
A plurality of columnar electrodes containing an electrode active material, a counter electrode containing a counter electrode active material and existing between the columnar electrodes, and a separation interposed between the columnar electrode and the counter electrode and having insulation and ionic conductivity. A method for manufacturing an electricity storage device comprising a membrane,
a winding step of arranging unit cells each including the columnar electrode, the counter electrode, and the separation membrane on a sheet-like conductor to obtain an array, and then winding the array;
In the winding step, when the axial direction of the columnar electrode is the Z axis, the X axis along the plane perpendicular to the Z axis, and the Y axis perpendicular to the X axis, the conductor along the X axis direction is a first conductor. , the conductor along the Y-axis direction is the second conductive part, the bending elastic modulus E x obtained by applying a load along the X-axis direction, and the bending elastic modulus E _x obtained by applying a load along the Y-axis direction. When the bending elastic modulus E _y is the length L _x , the thickness t _x and the quantity m of the first conductive part, and the length L _y , the thickness t _y and the quantity n of the second conductive part, Either the ratio E _y /E _x of the bending elastic modulus in the X-axis/Y-axis direction satisfies the following formula (1), or the ratio of the sum of the first conductive part and the second conductive part satisfies the following formula (2). or at least one of the following:
A method for manufacturing a power storage device.
0.5≦E _y /E _x ≦2.0…Formula (1)
0.5≦Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _m,x ³ )≦2.0 …Formula (2)

According to the present disclosure, rigidity can be further increased in a power storage device having a columnar electrode. The reason why such an effect is obtained is inferred as follows. For example, among the members that make up the battery structure, a sheet-like conductor that collects current from the counter electrode is sometimes arranged within the structure, but generally this conductor is arranged in one direction. Ru. A power storage device with this structure is weak against loads from the front and back directions of the conductor, but has extremely high bending rigidity against loads from the end surface side of the conductor because of the structure in which a plurality of conductors are integrated. Therefore, it is possible to adjust the balance of bending rigidity in the X/Y axis directions by distributing the arrangement direction of the sheet-like conductors arranged in large numbers inside the power storage device in the X/Y axis directions. , a battery structure having equal bending rigidity in both the X/Y axis directions can be manufactured.

FIG. 1 is an explanatory diagram showing an example of a power storage device 10. FIG. FIG. 2 is an explanatory diagram showing an example of a method for manufacturing the electricity storage device 10. FIG. An explanatory diagram showing an example of another power storage device 10A, 10B. An explanatory diagram showing an example of a power storage device 110. FIG. 2 is an explanatory diagram showing an example of a method for measuring bending elastic modulus. Load-displacement curve when measuring bending elastic modulus in Experimental Example 6.

(Electricity storage device)
The power storage device of the present disclosure described in the embodiment includes a plurality of columnar electrodes, a separation membrane, a counter electrode, a first conductive part, and a second conductive part. This electricity storage device may include an electrode current collector electrically connected to the columnar electrode, or a counter electrode current collector electrically connected to the counter electrode, the first conductive part, and the second conductive part. It may also be equipped with the following. This power storage device may be, for example, an electric double layer capacitor, a hybrid capacitor, a pseudo electric double layer capacitor, an alkali metal secondary battery, an alkali metal ion battery, or the like. Examples of carrier ions for power storage devices include alkali metal ions such as lithium ions, sodium ions, and potassium ions, and Group 2 ions such as magnesium ions, strontium ions, and calcium ions. Further, the counter electrode may be present around the columnar electrodes, or may be filled in the space between the columnar electrodes. Moreover, this electricity storage device may have a structure in which a plurality of columnar electrodes are bundled adjacent to a counter electrode with a separation membrane interposed therebetween. Furthermore, this electricity storage device may include an electrolytic solution in one or more of the columnar electrode, the counter electrode, and the separation membrane. The columnar electrode may have a current collecting member such as a current collecting wire embedded therein, or may not include this current collecting member. Furthermore, the columnar electrode may be a positive electrode or a negative electrode depending on the potential with respect to the counter electrode, but it is preferable to use a negative electrode. The same applies to the counter electrode, which may be either a positive electrode or a negative electrode, but is preferably a positive electrode. Here, for convenience of explanation, a lithium ion secondary battery in which a columnar electrode is used as a negative electrode, a counter electrode is used as a positive electrode, and lithium ions are used as a carrier will be described as a main example.

Here, the electricity storage device disclosed in this embodiment will be explained using the drawings. FIG. 1 is an explanatory diagram showing an example of a power storage device 10. The electricity storage device 10 includes a columnar electrode 12, a separation membrane 15, a counter electrode 16, a first conductive part 21, a second conductive part 22, an electrode current collector 25, and a counter electrode current collector 26. . The single cell 11 includes a columnar electrode 12, a separation membrane 15, and a counter electrode 16. This electricity storage device 10 includes a columnar electrode 12 containing an electrode active material, and a counter electrode 16 containing a counter electrode active material formed around the columnar electrode 12 with a separation membrane 15 in between. This electricity storage device 10 may have a structure in which a plurality of unit cells 11 each including a columnar electrode 12 on which a separation membrane 15 and a counter electrode 16 are formed are bundled. Moreover, this electricity storage device 10 may have a structure in which 200 or more columnar electrodes 12 are bundled together. Alternatively, the electricity storage device 10 may have a structure in which a columnar electrode 12, a separation membrane 15 formed on the surface of the columnar electrode 12, and a counter electrode 16 filled between the columnar electrodes 12 with the separation membrane 15 interposed therebetween. good.

The columnar electrode 12 is a member containing an electrode active material. Here, the term "column-shaped" includes not only those with a thickness that does not bend, but also those with a fiber-like thickness that can be bent. The columnar electrode 12 may be columnar, and its cross section may be circular or polygonal. In the power storage device 10, a plurality of columnar electrodes 12 are arranged in a predetermined direction. The outer periphery of the columnar electrode 12 other than the end connected to the electrode current collector 25 is covered with a separation membrane 15 . For example, the columnar electrodes 12 may have a capacity that is 1/n of the negative electrode capacity of the entire electricity storage device 10, and n pieces may be connected in parallel to the electrode current collector 25. The diameter D of the cross section perpendicular to the longitudinal direction of the columnar electrode 12 is preferably 10 μm or more, more preferably 15 μm or more, and may be 30 μm or more. Further, the diameter D of the columnar electrode 12 is preferably 800 μm or less, more preferably 500 μm or less, and may be 400 μm or less. When the diameter D is 10 μm or more, the strength of the electrode structure can be ensured and stable charging and discharging can be performed. Furthermore, when the diameter D is 800 μm or less, the distance traveled by carrier ions is not too long, and high output performance can be obtained. Further, when the diameter D is in the range of 10 to 500 μm, the energy density per unit volume can be further increased. Alternatively, within this range, the moving distance of carrier ions can be made shorter, and charging and discharging can be performed with a larger current. The length of this columnar body in the longitudinal direction can be determined as appropriate depending on the use of the electricity storage device, and may be in the range of 20 mm or more and 200 mm or less, for example. It is preferable that the length of the columnar body is 20 mm or more because it can further increase the battery capacity, and it is preferable that the length of the columnar body is 200 mm or less because it can further reduce the electrical resistance of the negative electrode.

The columnar electrode 12 preferably contains a carbon material as an electrode active material, and the electrode active material may be one or more of a bundle of carbon fibers 14 and an integrated carbon material. Carbon materials have high conductivity and are preferable for the columnar electrodes 12. Examples of the carbon material include one or more of graphite, coke, glassy carbon, non-graphitizable carbon, and pyrolytic carbon. Among these, graphites such as artificial graphite and natural graphite are preferred. Further, carbon fiber 14 having a graphite structure may be used. Such carbon fibers 14 preferably have crystals oriented in the longitudinal direction, which is the fiber direction. Further, it is preferable that the crystals are oriented radially from the center toward the outer peripheral surface when viewed in cross section in a direction perpendicular to the longitudinal direction (fiber direction). The diameter d of the carbon fiber 14 may be, for example, 5 μm or more, 7 μm or more, or 10 μm or more. Further, the diameter d of the carbon fiber 11 may be in the range of 50 μm or less, 25 μm or less, or 20 μm or less. The columnar electrode 12 may be obtained by twisting a plurality of carbon fibers 14, or may be obtained by binding a plurality of carbon fibers 14 with a binding material. The binder preferably has carrier ion conductivity, such as polyvinylidene fluoride (PVdF), a copolymer of PVdF and hexafluoropropylene (PVdF-HFP), polymethyl methacrylate (PMMA), and a copolymer of PMMA and acrylic polymer. Further, the columnar electrode 12 may be an integral body made by carbonizing a carbon material raw material formed into a columnar shape, or may be made by solidifying a carbonized carbon material with a binder or the like.

Alternatively, the columnar electrode 12 may be formed by forming a composite oxide capable of intercalating and releasing carrier ions into a columnar body. Examples of the composite oxide include lithium titanium composite oxide and lithium vanadium composite oxide. The negative electrode made of this composite oxide may have a conductive component formed on at least a portion of its surface. This conductive component can further enhance the conductivity. This conductive component is not particularly limited as long as it is a highly conductive material, and may be, for example, a metal.

The electrode current collector 25 is a conductive member and is electrically connected to the columnar electrode 12. This electrode current collector 25 is arranged on the side where the columnar electrode 12 is exposed. This electrode current collector 25 is made of, for example, carbon paper, aluminum, copper, titanium, stainless steel, nickel, iron, platinum, fired carbon, conductive polymer, conductive glass, etc., as well as adhesive, conductive, and acid-resistant materials. It is also possible to use aluminum, copper, or the like whose surface has been treated with carbon, nickel, titanium, silver, platinum, gold, or the like for the purpose of improving the reduction property. The shape of the electrode current collector 25 is not particularly limited as long as it can be connected to the columnar electrode 12. For example, it may be plate-shaped, foil-shaped, film-shaped, sheet-shaped, net-shaped, punched or expanded, or lath shaped. , a porous body, a foamed body, a formed body of fiber groups, and the like.

The separation membrane 15 has ionic conductivity for carrier ions (for example, lithium ions), insulates the columnar electrode 12 and the counter electrode 16, and is provided around the columnar electrode 12. The separation membrane 15 is formed on the entire outer circumferential surface of the columnar electrode 12 facing the counter electrode 16, and prevents a short circuit between the columnar electrode 12 and the counter electrode 16. This separation membrane 15 may be formed, for example, by producing a self-supporting membrane from a raw material solution containing resin and coating the surface of the columnar electrode 12 with this self-standing membrane, or by immersing the columnar electrode 12 in the raw material solution. It may also be formed by coating the surface of the material. Examples of the resin for the separation membrane 15 include polyvinylidene fluoride (PVdF), a copolymer of PVdF and hexafluoropropylene (PVdF-HFP), polymethyl methacrylate (PMMA), and a copolymer of PMMA and acrylic polymer. Examples include copolymers. For example, in the case of a copolymer of PVdF and HFP, a portion of the electrolyte swells and gels the membrane, resulting in an ion-conducting membrane. The thickness of this separation membrane 15 is, for example, preferably 2 μm or more, more preferably 5 μm or more, and may be 8 μm or more. It is preferable that the thickness is 2 μm or more in order to ensure insulation. In particular, if the thickness of the separation membrane 15 is 2 μm or more, it is easy to manufacture. Further, the thickness of the separation membrane 15 is preferably 15 μm or less, more preferably 10 μm or less. When the thickness is 15 μm or less, it is preferable in terms of suppressing a decrease in ion conductivity and further reducing the volume occupied in the cell. When the thickness of the separation membrane 15 is in the range of 2 to 15 μm, ion conductivity and insulation properties are suitable.

The separation membrane 15 may include an electrolytic solution that conducts ions that are carriers. Examples of this electrolytic solution include non-aqueous solvents. Examples of the solvent for the electrolyte include solvents for non-aqueous electrolytes. Examples of this solvent include carbonates, esters, ethers, nitriles, furans, sulfolanes, and dioxolanes, and these can be used alone or in combination. Specifically, carbonates include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate, vinylene carbonate, butylene carbonate, and chloroethylene carbonate, as well as dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate, and ethyl carbonate. - Chain carbonates such as n-butyl carbonate, methyl-t-butyl carbonate, di-i-propyl carbonate, and t-butyl-i-propyl carbonate, cyclic esters such as γ-butyl lactone and γ-valerolactone, Chain esters such as methyl formate, methyl acetate, ethyl acetate, and methyl butyrate; ethers such as dimethoxyethane, ethoxymethoxyethane, and diethoxyethane; nitrites such as acetonitrile and benzonitrile; and furans such as tetrahydrofuran and methyltetrahydrofuran. Examples include sulfolanes such as sulfolane, tetramethylsulfolane, and dioxolanes such as 1,3-dioxolane and methyldioxolane. This electrolytic solution may have a supporting salt containing ions, which is a carrier of the electricity storage device 10, dissolved therein. Examples of the supporting salt include LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiC(CF ₃ SO ₂ ) ₃ , LiSbF ₆ , LiSiF ₆ , LiAlF ₄ , LiSCN, Examples include LiClO ₄ , LiCl, LiF, LiBr, LiI, LiAlCl ₄ and the like. Among these, 1 selected from the group consisting of inorganic salts such as LiPF ₆ , LiBF ₄ and LiClO ₄ and organic salts such as LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ and LiC(CF ₃ SO _{2 )} 3 From the viewpoint of electrical properties, it is preferable to use a species or a combination of two or more kinds of salts. The concentration of this supporting salt in the electrolytic solution is preferably 0.1 mol/L or more and 5 mol/L or less, more preferably 0.5 mol/L or more and 2 mol/L or less.

The counter electrode 16 includes a counter electrode active material and is provided so as to fill the space between adjacent columnar electrodes 12 . The counter electrode 16 may include a counter electrode active material, a conductive material, and a binding material as necessary. The counter electrode 16 may include the columnar electrode 12 and have a hexagonal cross-sectional shape when the electricity storage device 10 is manufactured (see FIG. 1). This shape is preferable because when the columnar electrodes 12 having the positive electrode active material formed on the outer periphery are bundled, the counter electrode 16 is easily filled between the columnar electrodes 12 . The counter electrode 16 may be present between the plurality of columnar electrodes 12, and the outer shape is not limited to a hexagonal shape as shown in FIG. The counter electrode 16 may include a conductive material and may itself have conductivity. The counter electrode 16 may be formed, for example, by forming the separation membrane 15 on the outer periphery of the columnar electrode 12 and then applying the raw material of the counter electrode 16 to the outer periphery.

The counter electrode 16 may be made of, for example, a counter electrode composite material in which a counter electrode active material, a conductive material, and, if necessary, a binder are mixed. Examples of the counter electrode active material include a positive electrode active material that is capable of intercalating and deintercalating lithium, which is a carrier. Examples of the positive electrode active material include compounds containing lithium and a transition metal, such as oxides containing lithium and a transition metal element, and phosphoric acid compounds containing lithium and a transition metal element. Specifically, lithium-manganese composite oxides with basic composition formulas such as Li _(1-x) MnO ₂ (0≦x≦1, etc., the same applies hereinafter) and Li _(1-x) Mn ₂ O ₄ , etc. Lithium cobalt composite oxide with the formula Li _(1-x) CoO ₂ etc., lithium nickel composite oxide with the basic composition formula Li _(1-x) NiO ₂ etc., the basic composition formula Li _(1-x) Co _a Ni _b Mn _c O ₂ (a>0, b>0, c>0, a+b+c=1), Li _(1-x) Co _a Ni _b Mn _c O ₄ (0<a<1, 0<b Lithium cobalt nickel manganese composite oxide with <1, 1≦c<2, a+b+c=2), etc., lithium vanadium composite oxide with basic composition formula such as LiV ₂ O ₃ , etc., and lithium vanadium composite oxide with basic composition formula such as V ₂ O ₅ Transition metal oxides and the like can be used. Further, a lithium iron phosphate compound having the basic composition formula LiFePO ₄ or the like can be used as the positive electrode active material. Among these, lithium cobalt nickel manganese composite oxides such as LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ and LiNi _0.4 Co _0.3 Mn _0.3 O ₂ are preferred. Note that the "basic compositional formula" may include other elements such as Al and Mg.

The conductive material contained in the counter electrode 16 is not particularly limited as long as it is an electronically conductive material that does not adversely affect battery performance, and examples include graphite such as natural graphite (scaly graphite, flaky graphite), artificial graphite, acetylene black, One or a mixture of two or more of carbon black, Ketjen black, carbon whiskers, needle coke, carbon fiber, metals (copper, nickel, aluminum, silver, gold, etc.) can be used. The binder plays the role of binding active material particles and conductive material particles to maintain a predetermined shape. Fluororesins, thermoplastic resins such as polypropylene and polyethylene, ethylene propylene diene monomer (EPDM) rubber, sulfonated EPDM rubber, natural butyl rubber (NBR), etc. can be used alone or in a mixture of two or more. Furthermore, an aqueous binder such as a cellulose binder or an aqueous dispersion of styrene-butadiene rubber (SBR) can also be used.

In the counter electrode 16, the content of the positive electrode active material is preferably larger, preferably 70% by mass or more, and more preferably 80% by mass or more based on the entire mass of the counter electrode 16. The content of the conductive material is preferably in the range of 0% by mass or more and 20% by mass or less, and more preferably in the range of 0% by mass or more and 10% by mass or less, based on the entire mass of the counter electrode 16. Within this range, a decrease in battery capacity can be suppressed and sufficient conductivity can be provided. Further, the content of the binder is preferably in the range of 0.1% by mass or more and 5% by mass or less, and preferably in the range of 0.2% by mass or more and 3% by mass or less, based on the entire mass of the counter electrode 16. It is more preferable.

Further, inside the counter electrode 16, a sheet-shaped first conductive part 21 and a sheet-shaped second conductive part 22 are arranged along the Z-axis direction, which is the axial direction of the columnar electrode 12. The first conductive part 21 and the second conductive part 22 are made of a material having a lower volume resistivity than the counter electrode 16, and are members that improve the current collection efficiency of the counter electrode 16. The first conductive part 21 and the second conductive part 22 may be made of the same material or different materials, but are preferably made of the same material. The first conductive part 21 and the second conductive part 22 may be made of metal foil, for example, aluminum or stainless steel, and preferably aluminum. The first conductive part 21 is arranged along the X-axis direction (XZ plane) when the axial direction of the columnar electrode 12 is the Z-axis, the X-axis along the plane perpendicular to the Z-axis, and the Y-axis perpendicular to the X-axis. It may also be provided on the counter electrode 16 (see FIG. 1). The second conductive portion 22 may be provided on the counter electrode 16 along the Y-axis direction (YZ plane) in the XYZ axes. In this way, when sheet-like members exist inside the electricity storage device 10 in different directions, the bending rigidity can be further increased against loads from different directions.

The thickness of the first conductive part 21 is, for example, preferably 2 μm or more, more preferably 5 μm or more, and even more preferably 7 μm or more. Further, the thickness of the first conductive portion 21 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. A thickness of 2 μm or more is preferable from the viewpoint of improving the handling strength and conductivity of the member, and a thickness of 20 μm or less is preferable from the viewpoint of volumetric energy density since the presence of members that do not contribute to charging and discharging is further reduced. Although it is preferable that a plurality of first conductive parts 21 exist inside electricity storage device 10, they may all have the same thickness or may have different thicknesses. When one or more of the first conductive parts 21 have different thicknesses, it is preferable to use a thicker one closer to the outer periphery of the electricity storage device 10 from the viewpoint of improving bending rigidity. The first conductive part 21 exists between the single cells 11, but there may be a region between the single cells 11 where the first conductive part 21 is not provided.

The thickness of the second conductive portion 22 is, for example, preferably 2 μm or more, more preferably 5 μm or more, and even more preferably 7 μm or more. Further, the thickness of the second conductive portion 22 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. A thickness of 2 μm or more is preferable from the viewpoint of improving the handling strength and conductivity of the member, and a thickness of 20 μm or less is preferable from the viewpoint of volumetric energy density since the presence of members that do not contribute to charging and discharging is further reduced. Although it is preferable that a plurality of second conductive parts 22 exist inside electricity storage device 10, they may all have the same thickness or may have different thicknesses. When one or more of the second conductive parts 22 have different thicknesses, it is preferable to use the thicker ones closer to the outer periphery of the electricity storage device 10 from the viewpoint of improving bending rigidity. This second conductive part 22 may have the same thickness as the first conductive part 21, or may have a different thickness. The second conductive part 22 exists between the single cells 11, but there may be a region between the single cells 11 where the second conductive part 22 is not provided.

The counter electrode current collector 26 is a member that has conductivity and collects current from the counter electrode 16, and is electrically connected to the ends of the first conductive part 21 and the second conductive part 22. For the counter electrode current collector 26, the material and shape used for the electrode current collector 25 can be adopted, for example. Further, in FIG. 1, the counter electrode current collector 26 is arranged on the lower surface side of the electricity storage device 10, but it may be arranged on the side surface side.

The power storage device 10 includes, for example, a first stacked section 41 in which a first array 21 in which unit cells 11 each having a columnar electrode 12, a counter electrode 16, and a separation membrane 15 are arranged on a first conductive section 21 is stacked. , a second stacked section 42 in which a second array 22 in which the single cells 11 are arranged on a second conductive section 22 are stacked in a direction perpendicular to the first array 21. In addition, in the power storage device 10, further on the outer circumferential side of the first laminated portion 41 and the second laminated portion 42, a third laminated portion in which a third array body is laminated, a fourth laminated portion in which a fourth array body is laminated, etc. It may also have a multi-layer structure. Although FIG. 1 shows the first array body 31 in which one layer of single cells 11 is arranged on the first conductive part 21, two or more layers of single cells 11 may be arranged. Similarly, in the second array body 32, two or more layers of single cells 11 may be arranged on the second conductive portion 22.

The power storage device 10 has a bending elastic modulus E _x obtained by applying a load along the X-axis direction, and a bending elastic modulus E _y obtained applying a load along the Y-axis direction. The ratio E _y /E _x of the bending elastic modulus in the Y-axis direction may satisfy the following formula (1). If this relationship is satisfied, the bending rigidity of the electricity storage device 10 can be balanced within a higher range, which is preferable. This ratio E _y /E _x is preferably closer to 1, more preferably in the range of 0.75 or more and 1.5 or less, and even more preferably in the range of 0.8 or more and 1.2 or less.
0.5≦E _y /E _x ≦2.0…Formula (1)

The electricity storage device 10 has a first conductive part, where the length L _x , thickness t _x and quantity m of the first conductive part 21 and the length L _y , thickness _ty and quantity n of the second conductive part 22 are 21 and the second conductive portion 22 may satisfy the following formula (2). If this relationship is satisfied, the bending rigidity of the electricity storage device 10 can be balanced within a higher range, which is preferable. The abundance ratio of the conductive portion is preferably closer to 1, more preferably in the range of 0.75 or more and 1.5 or less, and even more preferably in the range of 0.8 or more and 1.2 or less. Note that power storage device 10 satisfies either formula (1) or formula (2), and more preferably satisfies both formula (1) and formula (2). Here _, Σ( _{t m,x}・L _m,x ³ ) is (t _x1 ·L _x1 ³ ), . . . (t _xm ·L _xm ³ ) of the first conductive portion 21 having the m-th thickness t _xm and length L _xm are calculated and integrated. Further, it is assumed that Σ(t _n,y ·L _n,y ³ ) is similarly calculated for the second conductive portions 22 from 1 to n.
0.5≦Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _m,x ³ )≦2.0 …Formula (2)

In this electricity storage device 10, the volume energy density is more preferably higher, for example, preferably 400 Wh/L or more, more preferably 500 Wh/L or more, and still more preferably 600 Wh/L or more. preferable. In this electricity storage device 10, the positive and negative electrode capacity ratio (negative electrode capacity/positive electrode capacity), which is the ratio of the capacity of the negative electrode active material to the capacity of the positive electrode active material, is preferably in the range of 1.0 or more and 1.5 or less, More preferably, it is in the range of 1.2 or less. The forming thickness of the counter electrode 16 is appropriately set according to the diameter D of the columnar electrode 12 and the positive/negative electrode capacity ratio, and may be, for example, in a range of 5 μm or more and 50 μm or less. The thickness of the counter electrode 16 is, for example, the maximum thickness of the portion formed on the columnar electrode 12.

(Method for manufacturing electricity storage device)
The manufacturing method of the present disclosure may be a method of manufacturing the electricity storage device 10 described above. This manufacturing method includes a lamination step. 2A and 2B are explanatory diagrams illustrating an example of a method for manufacturing the electricity storage device 10, in which FIG. 2A is an arrangement process, FIG. 2B is a first stacking process of the first array body 31, and FIG. 2C is a second stack process of the second array body 32. Lamination processing, FIG. 2D is an explanatory diagram of the manufactured electricity storage device 10. In this lamination process, the number of arrays of unit cells 11 and the number of stacked arrays of array bodies are adjusted so that the above formula (1) or the above formula (2) is satisfied, and the power storage device 10. The lamination process includes an array process, a first lamination process, and a second lamination process.

In the arrangement process, unit cells 11 each having a columnar electrode 12, a counter electrode 16, and a separation membrane 15 are arranged on a sheet-like first conductive part 21 to obtain a first array 31 (FIG. 2A). Further, in the arraying process, the single cells 11 are arrayed on the sheet-like second conductive portion 22 to obtain a second array body 32. The number of arrayed single cells 11 is appropriately set based on the shape of power storage device 10, the required discharge capacity, and the like, depending on the number of stacked arrays. In this process, the first array body 31 and the second array body 32 may be subjected to a press process.

In the first stacking process, a predetermined number of first array bodies 31 are stacked to form a first stacked section 41 (FIG. 2B). In this process, the first laminated portion 41 may be subjected to a press process. In the second lamination process, the lamination direction of the first laminated body 41 is changed, and a predetermined number of second array bodies 32 are laminated on the first laminated body 41 along a direction perpendicular to the first array body 31 (FIG. 2C). . In the second lamination process, a plurality of second array bodies 32 may be laminated to form a second laminated part 42, and this second laminated part 42 may be laminated on the first laminated part 41. Alternatively, in the second lamination process, the second array body 32 may be laminated in order on the first lamination part 41. In this process, the second laminated part 42 may be pressed, or the first laminated part 41 and the second laminated part 42 may be pressed after being formed. In this way, the electricity storage device 10 including the first conductive part 21 along the X-axis direction and the second conductive part 22 along the Y-axis direction can be manufactured.

It goes without saying that the present disclosure is not limited to the embodiments described above, and can be implemented in various forms as long as they fall within the technical scope of the present disclosure.

For example, in the above-described embodiment, the carrier of the electricity storage device is a lithium ion, but the carrier is not limited to this, and may also be an alkali metal ion such as a sodium ion or a potassium ion, or a group 2 element ion such as a calcium ion or a magnesium ion. good. Further, the positive electrode active material may contain carrier ions. Further, although the electrolytic solution is a non-aqueous electrolytic solution, it may be an aqueous electrolytic solution.

In the above-described embodiment, the example in which the columnar electrode 12 has a cylindrical shape has been described, but it is not particularly limited to this, and may have a shape such as a quadrangular prism or a hexagonal prism. Further, although the counter electrode 16 is shown to have a hexagonal columnar outer diameter, it may also have a quadrangular columnar shape or a cylindrical shape.

In the embodiments described above, the counter electrode active material is a transition metal composite oxide, but is not particularly limited, and may be, for example, a carbon material used in a capacitor. Carbon materials include, but are not particularly limited to, activated carbons, cokes, glassy carbons, graphites, non-graphitizable carbons, pyrolytic carbons, carbon fibers, carbon nanotubes, Examples include polyacenes. Among these, activated carbons exhibiting a high specific surface area are preferred. The activated carbon as a carbon material preferably has a specific surface area of 1000 m ² /g or more, more preferably 1500 m ² /g or more. When the specific surface area is 1000 m ² /g or more, the discharge capacity can be further increased. The specific surface area of this activated carbon is preferably 3000 m ² /g or less, more preferably 2000 m ² /g or less from the viewpoint of ease of production. Note that the positive electrode is thought to store electricity by adsorbing and desorbing at least one of anions and cations contained in the ion conductive medium, but it also absorbs and desorbs at least one of anions and cations contained in the ion conductive medium. It may also be used to store electricity.

In the embodiment described above, the power storage device 10 has the same number of vertical and horizontal single cells 11, but is not particularly limited to this, and may have an aspect ratio other than 1. FIG. 3 is an explanatory diagram of an example of another power storage device 10A, 10B, in which FIG. 3A is an explanatory diagram of an example of power storage device 10A, and FIG. 3B is an explanatory diagram of an example of power storage device 10B. As shown in FIG. 3A, even if the aspect ratio is not 1, if the above formula (1) and/or formula (2) is satisfied, the bending rigidity can be balanced and further increased. .

In the embodiment described above, the first laminated part 41 in which the first array bodies 31 are laminated, and the second laminated part 42 in which the second array bodies 32 are laminated, but the present invention is not limited to this, and FIGS. As shown in 3B, the power storage device 10B may have a structure in which an array in which all the single cells 11 are arranged around one conductor is wound. In this electricity storage device 10B, the conductor along the X-axis direction corresponds to the above-described first conductive part 21, and the conductor along the Y-axis direction corresponds to the above-described second conductive part 22. Even with such a structure, for example, if the above formula (1) and/or formula (2) is satisfied, the bending rigidity can be balanced and further increased. This power storage device 10B is manufactured by arranging unit cells 11 each having a columnar electrode 12, a counter electrode 16, and a separation membrane 15 on a sheet-like conductor to obtain an array, and then winding the array. It can be manufactured by a process.

In the electricity storage devices 10, 10A, and 10B described in detail above, the rigidity can be further increased in those in which the columnar electrode 12 surrounded by the separation membrane 15 is disposed within the counter electrode 16. The reason why such an effect is obtained is inferred as follows. For example, among the members constituting the battery structure, a sheet-like conductor that collects current from a counter electrode may be disposed within the structure of the power storage device 10. In this case, the conductor is generally arranged in one direction. FIG. 4 is an explanatory diagram showing an example of a power storage device 110 in which conductors are arranged in one direction. The power storage device 110 with this structure is weak against loads from the front and back directions of the conductor (vertical direction in FIG. 4) has extremely high bending rigidity. In the power storage device 10 of the present embodiment, by distributing the arrangement directions of a large number of sheet-like conductors (the first conductive part 21 and the second conductive part 22) arranged inside the power storage device in the X/Y axis direction, , it is possible to adjust the balance of bending rigidity in the X/Y axis directions, and it is possible to produce a battery structure having equal bending rigidity in both the X/Y axis directions.

Below, an example in which the above-described electricity storage device was specifically manufactured will be described as an experimental example. Note that Experimental Examples 1 to 5 correspond to Examples of the present disclosure, Experimental Example 6 corresponds to a comparative example, and Experimental Examples 7 and 8 correspond to reference examples.

(Production of electricity storage device)
A carbon fiber bundle with a diameter D of 156.5 μm obtained by twisting and bundling 400 carbon fibers (manufactured by Nippon Graphite Fiber Co., Ltd.) with a diameter d of 7 μm was used as a columnar electrode (negative electrode). This columnar electrode was coated with a solution of vinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP) dissolved in N-methylpyrrolidone (NMP) using a dip method and dried to form a film with a thickness of 5 μm. A polymer membrane as a separation membrane was uniformly applied to the surface of the negative electrode. Next, a positive electrode active material (LiNi _0.5 Co _0.2 Mn _0.3 O ₂ ), acetylene black (HS-100 manufactured by Denka) as a conductive material, and vapor grown carbon fiber (VGCF manufactured by Showa Denko) as a conductive material were added. A positive electrode composite paste was prepared by adding N-methylpyrrolidone to a mixture of polyvinylidene fluoride (PVdF7305 manufactured by Kureha Co., Ltd.) as a binder in a mass ratio of 90:4:2:4. A positive electrode slurry was dip-coated on the above polymer-coated negative electrode to form a positive electrode composite layer such that the thickness of the positive electrode composite material was 35 μm. Thus, the negative electrode/polymer film/positive electrode composite layer formed concentrically was cut into a length of 11 cm to obtain a columnar single cell.

The produced single cells were arranged and stacked according to the production procedure shown in FIG. 2 to produce an electricity storage device. An aluminum foil having a thickness of 7 μm was used as a conductor, and a predetermined number of single cells were arranged in a row on this foil and pressed and bound to produce a raft-like array. Two types of array bodies, a first array body and a second array body, were prepared so that the numbers of single cells in the vertical and horizontal directions in the power storage device were the same when stacked orthogonally. A predetermined number of these raft-shaped arrays were prepared and stacked, and then the stacking direction was changed and further stacked, and pressed in the XY axis direction to form a fiber battery group. The cross-sectional size of the produced electricity storage device was 4.5 mm x 4.5 mm. Note that all of the produced electricity storage devices had the same number of single cells and the same capacity.

(Experiment example 1)
After preparing 17 sets of first array bodies in which 11 concentric single cells were arranged on aluminum foil and 6 sets of second array bodies in which 17 single cells were arranged, and stacking 17 sets of first array bodies, Experimental example 1 was obtained by changing the stacking direction by 90 degrees and stacking three sets of second array bodies above and below the second array (see FIG. 2).

(Experiment examples 2 to 4)
After preparing 17 sets of first array bodies in which 12 single cells were arranged on aluminum foil and 5 sets of second array bodies in which 17 single cells were arranged, and stacking 17 sets of first array bodies, the stacking direction was changed. Experimental Example 2 consisted of two sets and three sets of second arrays stacked above and below the arrays at an angle of 90 degrees. In addition, 17 sets of first array bodies in which 10 single cells were arranged on aluminum foil and 7 sets of second array bodies in which 17 single cells were arranged were prepared, and after laminating 17 sets of first array bodies, Experimental Example 3 was obtained by stacking three sets and four sets of second array bodies above and below the stack with the direction changed by 90°. In addition, 17 sets of first array bodies in which 13 single cells were arranged on aluminum foil and 4 sets of second array bodies in which 17 single cells were arranged were prepared, and after laminating 17 sets of first array bodies, Experimental Example 4 was obtained by changing the direction by 90 degrees and stacking two sets of second arrays above and below.

(Experiment example 5)
An array in which all 17×17 single cells were arranged in a row on aluminum foil was prepared, and the array was wound from the end to produce a structure with a rectangular cross section (see FIG. 3B). This structure was pressed in the XY axis direction, and the resulting electricity storage device was designated as Experimental Example 5.

(Experiment example 6)
Experimental Example 6 And so. FIG. 4 is an explanatory diagram of a power storage device 110 that includes a unidirectional conductor.

(Experiment examples 7 and 8)
After preparing 17 sets of first array bodies in which 9 single cells were arranged on aluminum foil and 8 sets of second array bodies in which 17 single cells were arranged, and stacking 17 sets of first array bodies, the stacking direction was adjusted. Experimental Example 7 was obtained in which four sets of second arrays were stacked on top and bottom of the second array at an angle of 90 degrees. In addition, 17 sets of first array bodies in which 15 single cells were arranged on aluminum foil and 2 sets of second array bodies in which 17 single cells were arranged were prepared, and after laminating 17 sets of first array bodies, Experimental Example 8 was obtained by changing the direction by 90° and stacking one set and one set of second arrays above and below.

(bending test)
FIG. 5 is an explanatory diagram showing an example of a method for measuring bending elastic modulus. As shown in FIG. 5, a load was applied to the formed electricity storage device by "three-point bending", a "load-deflection" diagram was measured, and the bending elastic modulus was calculated from the slope of the linear region. In the bending test, a universal testing machine manufactured by Instron was used, the sample size was 4.5 mm x 4.5 mm x 9 cm, the distance between fulcrums L was 7 cm, and the bending load was applied at a speed of 1 mm/min.

(Results and discussion)
The bending elastic modulus E _{x and} E _y of each experimental example, their ratio E _y /E _x , the abundance ratio of the conductor Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _{m, x} ³ ) and other results are summarized in Table 1. Note that the bending elastic modulus was determined by setting the value in the X-axis direction of Experimental Example 6 as 100, and normalizing the values of the other experimental examples. FIG. 6 is a load-displacement curve when measuring the bending elastic modulus in Experimental Example 6. The slope of the load-displacement curve (flexural modulus) varies greatly depending on the relationship between the conductor arrangement direction and the load direction, and the rigidity in the X-axis direction on the end side of the conductor varies between the front and back sides of the conductor. It was found that the stiffness was greater than the stiffness in the Y-axis direction. As shown in Table 1, different rigidities in the X/Y axis directions were obtained depending on the direction in which the arrays were stacked and the number of layers stacked. The reason for this is that there is no difference in rigidity depending on the direction of each element group of the fiber electrode, so it was thought that the effect and influence of the direction of the conductor arranged inside the electricity storage device was large. The bending elastic modulus, which is an index representing the difficulty of bending deformation of a member, is expressed by the formula shown in FIG. That is, considering the influence of the conductor using Experimental Example 6 as an example, when bending in the Y-axis direction, the width is b (4.5 mm) and thickness h (7 μm x 17), but when bending in the X-axis direction In this case, the width is b (7 μm x 17) and the thickness h (4.5 mm), and the width and thickness are opposite, and the cube h is larger in the X-axis direction, so the X-axis direction is better than the Y-axis. It was thought that the rigidity would be higher compared to the direction. Therefore, by using the "ratio" of the total bending stiffness of each conductor arranged in the X-axis direction and the sum of the bending stiffness of each conductor arranged in the Y-axis direction as a parameter, the It was thought that rigidity could be defined. As shown in Table 1, if the ratio of conductors in the X/Y axis direction is within the range of formulas (1) and (2) below, where the ratio of the conductors in the X/Y axis direction is 1:2 to 2:1, the rigidity in the X/Y axis direction is It was found that it is possible to form a well-balanced structure of a power storage device. In formula (1), E _x is the bending elastic modulus obtained by applying a load along the X-axis direction, and E _y is the bending elastic modulus obtained by applying a load along the Y-axis direction. In addition, in formula (2), L _x , thickness t _x and quantity m are the length, thickness and quantity of the first conductive part along the X-axis direction, respectively, and L _y , thickness t _y and quantity n are the length, thickness, and quantity of the second conductive part along the Y-axis direction, respectively.
0.5≦E _y /E _x ≦2.0…Formula (1)
0.5≦Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _m,x ³ )≦2.0 …Formula (2)

Furthermore, the thinner the conductor is, the larger the volumetric energy density (Wh/L) can be designed. The volume energy density when the thickness of the conductor was changed was calculated by setting the conductor thickness to 7 μm as a reference value of 100. Table 2 summarizes the relationship between the thickness of the conductor and the volumetric energy density. As shown in Table 2, if the thickness of the conductor is 20 μm or less, a volumetric energy density of 95% or more is ensured, which is considered to be more preferable.

In the above-mentioned embodiment, a power storage device with the same number of vertical and horizontal (X, Y) single cells was considered, but for example, even if the power storage device has a different number of vertical and horizontal single cells, the bending rigidity can be balanced in the same way as above. be able to. Furthermore, in the above-described embodiment, the thickness of the conductor is the same in both the first array along the X-axis direction and the second array along the y-direction, but the conductors may have different thicknesses. . Further, although the thickness of the conductor is the same in all the first array bodies, it may be changed arbitrarily, and the same applies to the second array body. For example, when using conductors with different thicknesses, it was inferred that it is preferable to use them closer to the outer periphery from the viewpoint of increasing bending rigidity.

It goes without saying that the present disclosure is not limited to the embodiments described above, and can be implemented in various forms as long as they fall within the technical scope of the present disclosure.

10, 10A, 10B, 110 electricity storage device, 11 single cell, 12 columnar electrode, 12a end face, 14 carbon fiber, 15 separation membrane, 16 counter electrode, 21 first conductive part, 22 second conductive part, 25 electrode current collector, 26 counter electrode current collector, 31 first array, 32 second array, 41 first laminated portion, 42 second laminated portion, d, D diameter.

Claims (8)

a plurality of columnar electrodes containing an electrode active material;
a counter electrode containing a counter electrode active material and existing between the columnar electrodes;
a separation membrane interposed between the columnar electrode and the counter electrode and having insulation and ion conductivity;
When the axial direction of the columnar electrode is the Z-axis, the X-axis along the plane perpendicular to the Z-axis, and the Y-axis perpendicular to the X-axis, a sheet-like first a conductive part;
a sheet-shaped second conductive part provided on the counter electrode along the Y-axis direction,
The bending elastic modulus E _x obtained by applying a load along the X-axis direction, the bending elastic modulus E _y obtained by applying a load along the Y-axis direction, and the length L of the first conductive part. _x , thickness t _x and quantity m, length L _y of the second conductive part, thickness _ty and quantity n,
Either the ratio E _y /E _x of the bending elastic modulus in the X-axis/Y-axis direction satisfies the following formula (1), or the ratio of the sum of the first conductive part and the second conductive part satisfies the following formula (2). satisfies or at least one of
Electricity storage device.
0.5≦E _y /E _x ≦2.0…Formula (1)
0.5≦Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _m,x ³ )≦2.0 …Formula (2) The electricity storage device according to claim 1, which satisfies both the formula (1) and the formula (2). a first stacked section in which a first array body including unit cells including the columnar electrode, the counter electrode, and the separation membrane is arranged on the first conductive section; and a first stacked section in which the single cells are stacked on the second conductive section The electricity storage device according to claim 1 or 2, further comprising a second stacked section in which the second array bodies arranged above are stacked in a direction perpendicular to the first array bodies. The first conductive part and the second conductive part are conductors that are the same member, and an array body in which unit cells each including the columnar electrode, the counter electrode, and the separation membrane are arranged on the conductor. The electricity storage device according to claim 1 or 2, having a wound structure. The electricity storage device according to claim 1, wherein the first conductive part and the second conductive part have a thickness of 20 μm or less. The power storage device according to any one of claims 1 to 5, wherein the first conductive part and the second conductive part are aluminum foils. A plurality of columnar electrodes containing an electrode active material, a counter electrode containing a counter electrode active material and existing between the columnar electrodes, and a separation interposed between the columnar electrode and the counter electrode and having insulation and ionic conductivity. A method for manufacturing an electricity storage device comprising a membrane,
A first array body is obtained by arranging unit cells each including the columnar electrode, the counter electrode, and the separation membrane on a sheet-like first conductive part, and then the first array body is laminated to form a first laminated part. The single cells are arranged on a sheet-like second conductive part to obtain a second array, and then the second array is placed on the first laminate in a direction perpendicular to the first array. A lamination step of laminating the
In the lamination step, when the axial direction of the columnar electrode is the Z-axis, the X-axis along the plane perpendicular to the Z-axis, and the Y-axis perpendicular to the X-axis, the direction along which the first conductive part follows is the X-axis direction. The direction along the second conductive part is the Y-axis direction, and the bending elastic modulus E _x obtained by applying a load along the X-axis direction, and the bending elasticity obtained by applying a load along the Y-axis direction. When the ratio E _y is the length L _x , the thickness t _x and the quantity m of the first conductive part, and the length L _y , the thickness t _y and the quantity n of the second conductive part, the X axis/Y Whether the ratio of bending elastic modulus in the axial direction E _y /E _x satisfies the following formula (1) or whether the ratio of the sum of the first conductive part and the second conductive part satisfies the following formula (2). configure to be at least one,
A method for manufacturing a power storage device.
0.5≦E _y /E _x ≦2.0…Formula (1)
0.5≦Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _m,x ³ )≦2.0 …Formula (2) A plurality of columnar electrodes containing an electrode active material, a counter electrode containing a counter electrode active material and existing between the columnar electrodes, and a separation interposed between the columnar electrode and the counter electrode and having insulation and ionic conductivity. A method for manufacturing an electricity storage device comprising a membrane,
a winding step of arranging unit cells each including the columnar electrode, the counter electrode, and the separation membrane on a sheet-like conductor to obtain an array, and then winding the array;
In the winding step, when the axial direction of the columnar electrode is the Z axis, the X axis along the plane perpendicular to the Z axis, and the Y axis perpendicular to the X axis, the conductor along the X axis direction is a first conductor. , the conductor along the Y-axis direction is the second conductive part, the bending elastic modulus E x obtained by applying a load along the X-axis direction, and the bending elastic modulus E _x obtained by applying a load along the Y-axis direction. When the bending elastic modulus E _y is the length L _x , the thickness t _x and the quantity m of the first conductive part, and the length L _y , the thickness t _y and the quantity n of the second conductive part, Either the ratio E _y /E _x of the bending elastic modulus in the X-axis/Y-axis direction satisfies the following formula (1), or the ratio of the sum of the first conductive part and the second conductive part satisfies the following formula (2). or at least one of the following:
A method for manufacturing a power storage device.
0.5≦E _y /E _x ≦2.0…Formula (1)
0.5≦Σ(t _n,y・L _n,y ³ )/Σ(t _m,x・L _m,x ³ )≦2.0 …Formula (2)