WO2015166655A1

WO2015166655A1 - Battery and electronic apparatus

Info

Publication number: WO2015166655A1
Application number: PCT/JP2015/002234
Authority: WO
Inventors: Yasuhiro Nakamura
Original assignee: Sony Corporation
Priority date: 2014-05-02
Filing date: 2015-04-24
Publication date: 2015-11-05
Also published as: JP2015213013A; JP6303780B2

Abstract

A battery is provided including a battery element, an external packaging element that covers opposed main surfaces of the battery element, and that has openings at opposed first and second end surfaces of the battery element, and first and second cover bodies that cover the end surfaces of the battery element, at least one of the cover bodies including a concave portion.

Description

BATTERY AND ELECTRONIC APPARATUS

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority Patent Application JP 2014-095185 filed May 2, 2014, the entire contents of which are incorporated herein by reference.

The present disclosure relates to a battery element, a battery including an exterior packaging material that packages the battery element, and a battery apparatus including the battery.

Recently, as a power supply of a portable electronic apparatus and the like, a battery having the following configuration has been suggested (for example, refer to PTL 1).　Specifically, an exterior packaging material includes first and second laminate materials having substantially the same size as each other, a battery element that is accommodated in a concave portion formed in the first laminated material, and the first and second laminate materials which overlap each other in order an opening of the concave portion so as to be covered with the second laminated material, thereby sealing the periphery of the opening.　On an outer side of a bottom surface of the concave portion of the first laminate material, both ends of the first and second laminated materials are bonded to each other, and both sides surfaces are formed in an elliptical shape that swells toward the outside.

Japanese Unexamined Patent Application Publication No. 2005-166650

Summary

In a battery having the above-described configuration, when a large load is applied to the battery, the battery may be folded in half.　In this case, there is a concern that a folded portion of an exterior packaging material may pierce the battery element, and thus the battery element may be short-circuited.　As described above, when the battery element is short-circuited, the battery element may be subjected to thermal runaway.

Accordingly, it is desirable to provide a battery capable of improving stability, and an electronic apparatus including the battery.

In one embodiment, a battery is provided including a battery element, an external packaging element that covers opposed main surfaces of the battery element, and that has openings at opposed first and second end surfaces of the battery element, and first and second cover bodies that cover the end surfaces of the battery element, at least one of the cover bodies including a concave portion.

In another embodiment, an electronic apparatus includes a battery element.　The battery includes a battery element, an external packaging element that covers opposed main surfaces of the battery element, and that has openings at opposed first and second opposed end surfaces of the battery element, and
first and second cover bodies that cover the end surfaces of the battery element at least one of the cover bodies including a concave portion.

As described above, according to the present disclosure, it is possible to improve stability of a battery.

Fig. 1 is a perspective view illustrating an example of an external appearance of a battery according to a first embodiment of the present disclosure. Fig. 2 is an exploded perspective view illustrating an example of a configuration of the battery according to the first embodiment of the present disclosure. Fig. 3A is a perspective view illustrating an example of an external appearance of a battery element. Fig. 3B is a schematic cross-sectional view illustrating an example of a configuration of the battery element. Fig. 4A is a development view illustrating an example of a configuration of an exterior packaging material. Fig. 4B is a side view of the exterior packaging material illustrated in Fig. 4A. Fig. 4C is a rear view of the exterior packaging material illustrated in Fig. 4A. Fig. 5 is a perspective view illustrating an example of a shape of the exterior packaging material in which the battery element is accommodated. Fig. 6A is a schematic cross-sectional view illustrating an example of a configuration of a soft laminate material. Fig. 6B is a schematic cross-sectional view illustrating an example of a configuration of a hard laminate material. Fig. 6C is a schematic cross-sectional view illustrating an example of a configuration of a joint of the exterior packaging material. Fig. 7A is a perspective view illustrating an example of a shape of a top cover main body. Fig. 7B is a cross-sectional view illustrating an example of a cross-section taken along line VIIB-VIIB in Fig. 7A. Fig. 8A is a cross-sectional view illustrating an example of a cross-section taken along line VIIIA-VIIIA in Fig. 1. Fig. 8B is a cross-sectional view illustrating another example of the cross-section taken along line VIIIA-VIIIA in Fig. 1. Fig. 9A is a perspective view illustrating an example of a shape of a bottom cover. Fig. 9B is a cross-sectional view illustrating an example of a cross-section taken along line IXB-IXB in Fig. 9A. Fig. 10A is a perspective view illustrating an example of an external appearance of a battery according to a modification example of the first embodiment of the present disclosure. Fig. 10B is a perspective view illustrating an example of an external appearance of the battery according to the modification example of the first embodiment of the present disclosure. Fig. 10C is a perspective view illustrating an example of an external appearance of the battery according to the modification example of the first embodiment of the present disclosure. Fig. 10D is a perspective view illustrating an example of an external appearance of the battery according to the modification example of the first embodiment of the present disclosure. Fig. 10E is a perspective view illustrating an example of an external appearance of the battery according to the modification example of the first embodiment of the present disclosure. Fig. 10F is a perspective view illustrating an example of an external appearance of the battery according to the modification example of the first embodiment of the present disclosure. Fig. 11 is a block diagram illustrating an example of a configuration of an electronic apparatus according to a second embodiment of the present disclosure.

It is preferable that a joint of an exterior packaging material is configured by bonding sides of the exterior packaging material, or by disposing the sides of the exterior packaging material with a slight distance.　In a case where the exterior packaging material includes a first exterior packaging material and a second exterior packaging material, and a battery has a joint of the first exterior packaging material and a joint of the second exterior packaging material, it is preferable that a joint of a relatively hard exterior packaging material between the first exterior packaging material and the second exterior packaging material is provided at a position that faces a concave portion, or a position that approximately faces the concave portion.

For example, it is preferable that the exterior packaging material includes an opening at one end or both ends of a battery element.　In a case where the exterior packaging material has the opening at both ends, it is preferable that a cover body is provided to each opening.　In a case where a cover body is provided at each of the both ends of the exterior packaging material, it is preferable that at least one of the cover bodies has a concave portion in a surface that faces the joint of the exterior packaging material, and it is more preferable that both of the cover bodies have a concave portion in the surfaces thereof.

Embodiments of the present disclosure will be described in the following order with reference to the attached drawings.　In addition, the same reference sign will be given to the same portion or a corresponding portion in the drawings of the following embodiments.
1　First Embodiment (Example of Battery)
1.1　Configuration of Battery
1.2　Method of Manufacturing Battery
1.3　Effect
1.4　Modification Example
2　Second Embodiment (Example of Electronic Apparatus)
2.1　Configuration of Electronic Apparatus
2.2　Effect
(1　First Embodiment)

(1.1　Configuration of Battery)

As illustrated in Figs. 1 and 2, a battery according to a first embodiment of the present disclosure includes a battery element 1, an exterior packaging material 2 that packages the battery element 1 and has an opening at both ends, and a top cover (first cover body) 3 and a bottom cover (second cover body) 4 which are fitted into the openings at both ends of the exterior packaging material 2, respectively.　As illustrated in Fig. 2, the battery may further include a label 6 that is a surface member, and a surface of the exterior packaging material 2 may be covered with the label 6.

The battery has a flat shape having two main surfaces, and a joint L1 of the exterior packaging material 2 is provided on one main surface thereof.　The top cover 3 is provided with a positive electrode terminal 3h, a negative electrode terminal 3i, and an identification terminal 3j.　A positive electrode lead 5a and a negative electrode lead 5b are provided on one opening side of the exterior packaging material 2.　In this specification, in both ends of the battery or the battery element 1, a side in which the positive electrode lead 5a and the negative electrode lead 5b are provided is referred to as a top side, and the opposite side is referred to as a bottom side.

Hereinafter, the battery element 1, the exterior packaging material 2, the top cover 3, the bottom cover 4, and the label 6 will be described.

Battery Element

As illustrated in Fig. 3A, the battery element 1 is, for example, a wound type battery element having a flat shape.　For example, the positive electrode lead 5a and the negative electrode lead 5b protrude from one end of the battery element 1 in the same direction.　The battery element 1 is a so-called lithium ion secondary battery.　For example, the positive electrode lead 5a and the negative electrode lead 5b are configured of a metal material such as aluminum, copper, nickel, and stainless steel, and have a thin plate shape or a network shape.　It should be appreciated that the term "battery element" as used herein includes any suitable configuration in relation to any suitable application and use thereof.　For example, the battery element can include any suitable configuration relating to any suitable type of electrochemical cell including and in relation to lithium ion battery technology, alkaline battery technology,　fuel cell technology, and the like.

As illustrated in FIG. 3B, the battery element 1 includes a positive electrode 11, a negative electrode 12, a separator 13, and an electrolyte layer 14.　For example, the positive electrode 11, the negative electrode 12, and the separator 13 have an elongated rectangular shape.　For example, the battery element 1 has a wound structure in which the positive electrode 11 and the negative electrode 12 are wound through the separator 13 and the electrolyte layer 14 in a longitudinal direction.　The electrolyte layer 14 is provided between the positive electrode 11 and the separator 13 and between the negative electrode 12 and the separator 13, respectively.

Positive Electrode

For example, the positive electrode 11 includes a positive electrode current collector 11A and a positive electrode active material layer 11B provided on both surfaces of the positive electrode current collector 11A.　In addition, although not illustrated, the positive electrode active material layer 11B may be provided on only one surface of the positive electrode current collector 11A.　The positive electrode lead 5a is attached to the positive electrode current collector 11A through welding and the like.

For example, the positive electrode current collector 11A is configured of metal foil such as aluminum foil, nickel foil, and stainless steel foil.　For example, the positive electrode active material layer 11B includes one kind of or two or more kinds of positive electrode materials, which are capable of intercalating and deintercalating lithium ions, as a positive electrode active material.　The positive electrode active material layer 11B includes a conductive agent such as graphite and a binding agent such as polyvinylidene fluoride as necessary.

As the positive electrode materials capable of intercalating and deintercalating lithium ions, for example, a lithium-containing compound such as a lithium oxide, a lithium phosphorous oxide, a lithium sulfide, and an interlayer compound that includes lithium are appropriate, and two or more kinds thereof may be mixed and used.　To increase an energy density, a lithium-containing compound that includes lithium, a transition metal element, and oxygen (O) is preferable.　Examples of the lithium-containing compound include a lithium composite oxide having a layered rock salt type structure expressed by Formula (A), a lithium composite phosphate having an olivine structure expressed by Formula (B), and the like.　It is more preferable that the lithium-containing compound includes at least one element selected from the group consisting of cobalt (Co), nickel (Ni), manganese (Mn), and iron (Fe) as a transition metal element.　Examples of the lithium-containing compound include a lithium composite oxide having a layered rock salt type structure expressed by Formula (C), Formula (D), or Formula (E), a lithium composite oxide having a spinel type structure expressed by Formula (F), a lithium composite phosphate having an olivine type structure expressed by Formula (G), and the like.　Specific examples of the lithium-containing compound include LiNi_0.50Co_0.20Mn_0.30O₂, Li_aCoO₂ (a is approximately equal to 1), Li_bNiO₂ (b is approximately equal to 1), Li_c1Ni_c2Co_1-c2O₂ (c1 is approximately equal to 1, 0<c2<1), Li_dMn₂O₄ (d is approximately equal to 1), Li_eFePO₄(e is approximately equal to 1), and the like.

Li_pNi_(1-q-r)Mn_qM1_rO_(2-y)X_z ... (A)
(provided that, in Formula (A), M1 represents at least one kind of element excluding nickel (Ni) and manganese (Mn) among elements selected from Group 2 to Group 15.　X represents at least one kind of element excluding oxygen (O) among elements of Group 16 and elements of Group 17.　p, q, r, y, and z are values in the following ranges.　That is, p is equal to or greater than 0 and is equal or less than 1.5, q is equal to or greater than 0 and is equal to or less than 1.0, r is equal to or greater than 0 and is equal to or less than 1.0, y is equal to or greater than -0.10 and is equal to or less than 0.20, and z is equal to or greater than 0 and is equal to or less than 0.2.)

Li_aM2_bPO₄ ... (B)
(provided that, in Formula (B), M2 represents at least one kind of element among elements selected from Group 2 and Group 15, a and b are values in the following ranges.　That is, a is equal to or greater than 0 and is equal to or less than 2.0, and b is equal to or greater than 0.5 and is equal to or less than 2.0.)

Li_fMn_(1-g-h)Ni_gM3_hO_(2-j)F_k ... (C)
(provided that, in Formula (C), M3 represents at least one kind of element selected from the group consisting of cobalt (Co), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W).　f, g, h, j, and k are values in the following ranges.　That is f is equal to or greater than 0.8 and is equal to or less than 1.2, g is greater than 0 and is less than 0.5, h is equal to or greater than 0 and is equal to or less than 0.5, g+h<1, j is equal to or greater than -0.1 and is equal to or less than 0.2, and k is equal to or greater than 0 and is equal to or less than 0.1.　In addition, a composition of lithium is different in accordance with a charging and discharging state, and a value of f shows a value in a completely discharged state.)

Li_mNi_(1-n)M4_nO_(2-p)F_q ... (D)
(provided that, in Formula (D), M4 represents at least one kind of element selected from the group consisting of cobalt (Co), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W).　m, n, p, and q are values in the following ranges.　That is, m is equal to or greater than 0.8 and is equal to or less than 1.2, n is equal to or greater than 0.005 and is equal to or less than 0.5, p is equal to or greater than -0.1 and is equal to or less than 0.2, and q is equal to or greater than 0 and is equal to or less than 0.1.　In addition, a composition of lithium is different in accordance with a charging and discharging state, and a value of m shows a value in a completely discharged state.)

Li_rCo_(1-s)M5_sO_(2-t)F_u ... (E)
(provided that, in Formula (E), M5 represents at least one kind of element selected from the group consisting of nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W), r, s, t, and u are values in the following ranges.　That is, r is equal to or greater than 0.8 and is equal to or less than 1.2, s is equal to or greater than 0 and is equal to or less than 0.5, t is equal to or greater than -0.1 and is equal to or less than 0.2, u is equal to or greater than 0 and is equal to or less than 0.1.　In addition, a composition of lithium is different in accordance with a charging and discharging state, and a value of r shows a value in a completely discharged state.)

Li_vMn_2-wM6_wO_xF_y ... (F)
(provided that, in Formula (F), M6 represents at least one kind of element selected from the group consisting of cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W).　v, w, x, and y are values in the following ranges.　That is, v is equal to or greater than 0.9 and is equal to or less than 1.1, w is equal to or greater than 0 and is equal to or less than 0.6, x is equal to or greater than 3.7 and is equal to or less than 4.1, and y is equal to or greater than 0 and is equal to or less than 0.1.　In addition, a composition of lithium is different in accordance with a charging and discharging state, and a value of v shows a value in a completely discharged state.)

Li_zM7PO₄ ... (G)
(provided that, in formula (G), M7 represents at least one kind of element selected from the group consisting of cobalt (Co), manganese (Mn), iron (Fe), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), niobium (Nb), copper (Cu), zinc (Zn), molybdenum (Mo), calcium (Ca), strontium (Sr), tungsten (W), and zirconium (Zr).　z is a value in the following range.　That is, z is equal to or greater than 0.9 and is equal to or less than 1.1.　In addition, a composition of lithium is different in accordance with a charging and discharging state, and a value of z shows a value in a completely discharged state.)

In addition to the above-described compounds, examples of the positive electrode material capable of intercalating and deintercalating lithium ions also include inorganic compounds such as MnO₂, V₂O₅, V₆O₁₃, NiS, and MoS which do not include lithium.

The positive electrode material capable of intercalating and deintercalating lithium ions may be other materials.　In addition, two or more kinds of the above-described positive electrode materials may be mixed in an arbitrary combination.

Negative Electrode

For example, the negative electrode 12 includes a negative electrode current collector 12A, and a negative electrode active material layer 12B that is provided on both surfaces of the negative electrode current collector 12A.　In addition, although not illustrated, the negative electrode active material layer 12B may be provided on only one surface of the negative electrode current collector 12A. The negative electrode lead 5b is attached to the negative electrode current collector 12A through welding and the like.

For example, the negative electrode current collector 12A is configured of metal foil such as copper foil, nickel foil, and stainless steel foil. the negative electrode active material layer 12B includes one kind of or two or more kinds of negative electrode materials, which are capable of intercalating and deintercalating lithium ions, as a negative electrode active material.　The negative electrode current collector 12A may include the same binding agent as in the positive electrode active material layer 11B as necessary.

In addition, in the battery, an electrochemical equivalent of the negative electrode material capable of intercalating and deintercalating lithium ions is set to be higher than an electrochemical equivalent of the positive electrode 11, and is set in order for lithium metal not to precipitate to the negative electrode 12 during charging.

Examples of the negative electrode material, which is capable of intercalating and deintercalating lithium ions, include carbon materials such as hardly graphitizable carbon, easily graphitizable carbon, graphite, pyrolytic carbons, cokes, glass-like carbons, an organic polymeric compound fired body, carbon fiber, and activated charcoal.　As the graphite, it is preferable to use natural graphite that is subjected to spheroidizing treatment, and approximately spherical artificial graphite.　As the artificial graphite, artificial graphite obtained by graphitizing mesocarbon microbead (MCMB), or artificial graphite obtained by graphitizing and pulverizing coke raw material is preferable.　Examples of the cokes include pitch coke, needle coke, petroleum coke, and the like.　The organic polymeric compound fired body represents a material obtained by firing a polymeric material such as a phenol resin and a furan resin at an appropriate temperature for carbonization, and is partially classified into hardly graphitizable carbon or easily graphitizable carbon.　In addition, examples of the polymeric material include polyacetylene, polypyrrole, and the like.　The carbon materials are preferable because a variation in a crystal structure during charging and discharging is very small, and high charging and discharging capacity and satisfactory cycle characteristics can be obtained.　Particularly, the graphite is preferable because an electrochemical equivalent is large, and a high energy density can be obtained.　In addition, the hardly graphitizable carbon is preferable because excellent characteristics are obtained.　Furthermore, a material in which a charging and discharging potential is low, specifically, a material in which the charging and discharging potential is close to that of a lithium metal is preferable because a high energy density of the battery is easily realized.

Examples of the negative electrode material, which is capable of intercalating and deintercalating lithium ions, also include a material, which is capable of intercalating and deintercalating lithium ions and includes at least one kind of a metallic element and a metalloid element as a constituent element.　Here, the negative electrode 12, which includes the negative electrode material, is referred to as an alloy-based negative electrode.　When using the material, a high energy density can be obtained.　Particularly, it is more preferable to use the material in combination with a carbon material because a high energy density can be obtained and excellent cycle characteristics can be obtained.　The negative electrode material may be an elementary substance, an alloy, or a compound of a metallic element or a metalloid element, and the negative electrode material may at least partially have one or more kinds of phases of the elements.　In addition, in the present disclosure, in addition to an alloy of two or more kinds of metallic elements, the term "alloy" also includes an alloy including one or more kinds of metallic elements and one or more kinds of metalloid elements.　In addition, the alloy may include a nonmetallic element.　The texture of the alloy includes a solid solution, a eutectic crystal (a eutectic mixture), an intermetallic compound, and a texture in which two or more kinds of these textures coexist.

Examples of the metallic element or the metalloid element, which constitutes the negative electrode material, include magnesium (Mg), boron (B), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), bismuth (Bi), cadmium (Cd), silver (Ag), zinc (Zn), hafnium (Hf), zirconium (Zr), yttrium (Y), palladium (Pd), platinum (Pt), and the like.　These may be crystalline materials or amorphous materials.

Among these, as the negative electrode material, a material, which includes a metallic element or a metalloid element of Group 4B in a short-period type periodic table as a constituent element, is preferable, and a material, which includes at least one of silicon (Si) and tin (Sn), is more preferable.　This is because silicon (Si) and tin (Sn) have large capacity of intercalating and deintercalating lithium (Li) ions and a high energy density can be obtained.

Examples of an alloy of tin (Sn) include alloys which include at least one kind of element selected from the group consisting of silicon (Si), nickel (Ni), copper (Cu), iron (Fe), cobalt (Co), manganese (Mn), zinc (Zn), indium (In), silver (Ag), titanium (Ti), germanium (Ge), bismuth (Bi), antimony (Sb), and chromium (Cr) as a secondary constituent element other than tin (Sn).　Examples of an alloy of silicon (Si) include alloys which include at least one kind of element selected from the group consisting of tin (Sn), nickel (Ni), copper (Cu), iron (Fe), cobalt (Co), manganese (Mn), zinc (Zn), indium (In), silver (Ag), titanium (Ti), germanium (Ge), bismuth (Bi), antimony (Sb), and chromium (Cr) as a secondary constituent element other than silicon (Si).

Examples of a compound of tin (Sn) or silicon (Si) include compounds which include oxygen (O) or carbon (C), and the above-described secondary constituent element may be included in addition to tin (Sn) or silicon (Sn).

As the negative electrode material which is capable of intercalating and deintercalating lithium ions, other metallic compounds or polymeric materials may be exemplified.　Examples of other metallic compounds include oxides such as MnO₂, V₂O₅, and V₆O₁₃, sulfides such as NiS and MoS, and lithium nitrides such as LiN₃.　Examples of the polymeric materials include polyacetylene, polyaniline, polypyrrole, and the like.

Separator

The separator 13 is a component which isolates the positive electrode 11 and the negative electrode 12 from each other so as to prevent current short-circuiting due to mutual contact of the electrodes, and allows lithium ions to pass therethrough.　For example, the separator 13 is configured of a porous membrane formed from a synthetic resin such as polytetrafluoroethylene, polypropylene, and polyethylene, or a porous membrane of a ceramic, and may have a structure in which two or more kinds of the porous membranes are laminated.　Among these, the polyolefin porous membrane is preferable because the short-circuiting prevention effect is excellent, and an improvement in stability of the battery due to a shut-down effect can be realized.　Particularly, polyethylene can obtain the shut-down effect in a range of 100 degrees of Celsius to 160 degrees of Celsius, and electrochemical stability is excellent, and thus polyolefin is preferable as a material that constitutes the separator 13.　In addition, polypropylene is also preferable, and a resin having chemical stability may be used by copolymerizing or blending the resin with polyethylene or polypropylene.

Electrolyte Layer

The electrolyte layer 14 includes a nonaqueous electrolytic solution and a polymeric compound serving as a support body that supports the nonaqueous electrolytic solution, and the polymeric compound swells due to the nonaqueous electrolytic solution.　The content rate of the polymeric compound can be appropriately adjusted.　As the electrolyte layer 14 having such a configuration, a gel-shaped electrolyte layer is preferable.　This is because high ion conductivity can be obtained, and liquid leakage can be prevented.

For example, the nonaqueous electrolytic solution includes a solvent and an electrolyte salt.　Examples of the solvent include ordinary temperature molten salts such as 4-fluoro-1,3-dioxolane-2-one, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, gamma-butyrolactone, gamma-valerolactone, 1,2-dimethoxyethane ethane, tetrahydrofuran, 2-methyl tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, methyl acetate, methyl propionate, ethyl propionate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N,N-dimethylformamide, N-methylpyrrolidinone, N-methyl-oxazolidinone, nitromethane, nitroethane, sulfolane, dimethyl sulfoxide, trimethyl phosphate, triethyl phosphate, ethylene sulfide, bis-trifluoromethylsulfonyl imide trimethylhexyl ammonium, and the like.　Among these, it is preferable that one or more kinds of solvents selected from the group consisting of 4-fluoro-1,3-dioxolane-2-one, ethylene carbonate, propylene carbonate, vinylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and ethylene sulfide are mixed and used when considering that excellent charging and discharging capacity characteristics and charging and discharging cycle characteristics can be obtained.　The electrolyte layer 14 may include a known additive so as to improve battery characteristics.

The electrolyte salt may include one or more kinds of materials in a mixed state.　Examples of the electrolyte salt include lithium hexafluorophosphate (LiPF₆), lithium bis(pentafluoroethanesulfonyl)imide (Li(C₂F₅SO₂)2N), lithium perchlorate (LiClO₄), lithium hexafluoroarsenate (LiAsF₆), lithium tetrafluoroborate (LiBF₄), lithium trifluoromethanesulfonate (LiSO₃CF₃), lithium bis(trifluoromethanesulfonyl)imide (Li(CF₃SO₂)₂N), lithium tris(trifluoromethanesulnyl)methyl (LiC(SO₂CF₃)₃), lithium chloride (LiCl), and lithium bromide (LiBr).

Examples of the polymeric compound include polyacrylonitrile, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, polysiloxane, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene, and polycarbonate.　Particularly, polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene, or polyethylene oxide is preferable when considering electrochemical stability.

Exterior Packaging Material

The exterior packaging material is configured of a laminated material such as a laminate film.　Specifically, as illustrated in Figs. 4A to 4C, the exterior packaging material 2 includes a soft laminate material (first exterior packaging material) 2a provided with an accommodation portion 25 that is configured to accommodate the battery element 1, and a hard laminate material (second exterior packaging material) 2b that is provided on the soft laminate material 2a to overlap therewith so as to cover the accommodation portion 25.　The accommodation portion 25 has a concave shape in a surface on one side of the soft laminate material 2a.　The soft laminate material 2a and the hard laminate material 2b are bonded to each other at the periphery of the accommodation portion 25 through thermal welding and the like.　A thermal-welding sheet 25a is provided on a protruding surface 2S on a rear side of a bottom surface of the accommodation portion 25.

The soft laminate material 2a is suitable to form the accommodation portion 25, into which the battery element 1 is inserted, through a deep drawing process, and it is preferable that the soft laminate material 2a is softer than the hard laminate material 2b.　As illustrated in Fig. 6A, the soft laminate material 2a has a structure in which a bonding layer 26a, a metal layer 27a, and a surface protective layer 28a are sequentially laminated.　In a state in which the exterior packaging material 1 is closed, the bonding layer 26a becomes an outer side (side that comes into contact with the hard laminate material 2b).

The bonding layer 26a is melted with heat, an ultrasonic wave, and the like, and has a function of being welded to the hard laminate material 2b, and the like. As a material of the bonding layer 26a, a material, which does not cause modification of a polymer electrolyte and the like which are included in the battery element 1, is preferable.　As the material, for example, polypropylene such as cast polypropylene (CPP) may be used.　As the thickness of the bonding layer 26a, for example, a thickness of approximately 30 micrometers is selected.

The metal layer 27a has a function of preventing intrusion of moisture into the inside of the battery.　As a material of the metal layer 27a, for example, annealed aluminum (JIS A8021P-O) or (JIS A8079P-O), and the like may be used.　In addition, the thickness of the metal layer 27a is selected, for example, in a range of approximately 30 micrometers to approximately 130 micrometers.

The surface protective layer 28a has a function of protecting a surface of the soft laminate material 2a.　As a material of the surface protective layer 28a, for example, nylon, polyethylene terephthalate (PET), and the like may be used.　The thickness of the surface protective layer 28a is selected, for example, in a range of approximately 10 micrometers to approximately 30 micrometers.

It is preferable that the hard laminate material 2b retains a shape after bending, and resists deformation applied from the outside.　The hard laminate material 2b is harder than the soft laminate material 2a.　As illustrated in Fig. 6B, the hard laminate material 2b has a laminated structure in which a bonding layer 26b, a metal layer 27b, and a surface protective layer 28b are sequentially laminated.　In a state in which the exterior packaging material 2 is closed, the bonding layer 26b becomes an inner side (a side that comes into contact with the soft laminate material 2a).

The bonding layer 26b and the surface protective layer 28b of the hard laminate material 2b are the same as the bonding layer 26a and the surface protective layer 28a of the soft laminate material 2a.　The metal layer 27b is harder than the metal layer 27a.　For example, as the metal layer 27b, aluminum (JIS A3003P-H18) or (JIS A3004P-H18) which is not annealed, and the like may be used.　In addition, for example, the thickness of the metal layer 27b is selected in a range of approximately 30 micrometers to approximately 130 micrometers.　In addition, the thickness of each of the soft laminate material 2a and the hard laminate material 2b is preferably selected in consideration of the total thickness.

As illustrated in Fig. 4A, the soft laminate material 2a and the hard laminate material 2b have an approximately rectangular shape, and are disposed to overlap each other in a deviating manner in a longitudinal direction.　That is, a bonding region 2Ra in which only the soft laminate material 2a exists is provided at one end in the longitudinal direction of the soft laminate material 2a and the hard laminate material 2b which overlap each other, and a bonding region 2Rb in which only the hard laminate material 2b exists is provided at the other end.　In a state in which the hard laminate material 2b is curved in a tubular shape and is closed, the bonding regions 2Ra and 2Rb are joined together on a main surface of the battery element 1 covered with the soft laminate material 2a, that is, on the protruding surface 2S on the rear side of the bottom surface of the accommodation portion 25, and are bonded to each other through thermal welding and the like.

The thermal-welding sheet 25a is an auxiliary member that bonds parts of the surface protective layer 28a of the soft laminate material 2a, which face each other, on the protruding surface 2S of the rear side of the bottom surface of the accommodation portion 25.　The thickness of the thermal-welding sheet 25a is preferably approximately 10 micrometers to approximately 60 micrometers when considering the total thickness of the exterior packaging material 2.　As a material of the thermal-welding sheet 25a, a material having a melting point in a temperature range that has no thermal effect on the battery element 1 is preferable, and for example, a material having a melting point of approximately 100 degrees of Celsius is used.

A width of the soft laminate material 2a in a short direction is set to be narrower than a width of the hard laminate material 2b in a short direction.　A bonding region 2Rc in which only the hard laminate material 2b exists is provided at one end in a short direction of the soft laminate material 2a and the hard laminate material 2b which overlap each other, and the one end side becomes a top side.　In a state in which the exterior packaging material 2 is closed, the bonding layer 26b of the hard laminate material 2b in the bonding region 2Rc is bonded to a peripheral surface of the top cover 3 through thermal welding and the like.　On the other hand, the bonding region is not provided at the other end, and ends of the soft laminate material 2a and the hard laminate material 2b are flush with each other, and the other end becomes a bottom side.　In addition, a bonding region in which only the hard laminate material 2b exists may be provided on the end on the other side, and in a state in which the exterior packaging material 2 is closed, the bonding layer 26b of the hard laminate material 2b in the bonding region may be bonded to a peripheral surface of the bottom cover 4 by thermal welding and the like.

For example, the soft laminate material 2a is a soft laminate film having flexibility.　The soft laminate material 2a has an approximately rectangular shape.　Specifically, the soft laminate material 2a has a set of

long sides

21a and 22a having the same length as each other, and a set of

short sides

23a and 24a having the same length as each other.

For example, the hard laminate material 2b is a hard laminate film having flexibility.　The hard laminate material 2b has an approximately rectangular shape.　Specifically, the hard laminate material 2b has a set of

long sides

21b and 22b having the same length as each other, and a set of

short sides

23b and 24b having the same length as each other.

The short side 23a of the soft laminate material 2a is disposed on an outer side in comparison to the short side 23b of the hard laminate material 2b, and the short side 24a of the soft laminate material 2a is disposed on an inner side in comparison to the short side 24b of the hard laminate material 2b.　According to this, the above-described bonding regions 2Ra and 2Rb are provided at both ends in a longitudinal direction of the soft laminate material 2a and the hard laminate material 2b which overlap each other, respectively.

The length of the

long sides

21b and 22b of the hard laminate material 2b is set in such a manner that the

short sides

23b and 24b are bonded to each other or face each other with a slight distance in a state in which the exterior packaging material 2 is closed.　The length of the

long sides

21a and 22a of the soft laminate material 2a is selected to be shorter than the length of the

long sides

21b and 22b of the hard laminate material 2b.　For example, the length of the

long sides

21a and 22a is set in such a manner that the

short sides

23a and 24a are bonded to each other or face each other with a distance in a state in which the exterior packaging material 2 is closed.　Here, a gap of the soft laminate material 2a is not limited to a slight width, and may be set to a certain extent of width.

The length of the

short sides

23a and 24a of the soft laminate material 2a is set to be slightly shorter than the length of the

short sides

23b and 24b of the hard laminate material 2b.　According to this, the soft laminate material 2a and the hard laminate material 2b overlap each other in such a manner that only the hard laminate material 2b exists on a top side, and thus the bonding region 2Rc is provided on the top side.

As illustrated in Fig. 5, in a state in which the exterior packaging material 2 is closed, a joint L1 and a joint L2 are constituted on a main surface of the battery element 1 covered with the soft laminate material 2a in a state in which the exterior packaging material 2 is closed.　Specifically, the

short sides

23b and 24b of the hard laminate material 2b come into contact with or face each other with a slight distance on the protruding surface 2S on the rear side of the bottom surface of the accommodation portion 25, and thus the joint L1 of the hard laminate material 2b is constituted on the accommodation portion 25.　In addition, the

short sides

23a and 24a of the soft laminate material 2a come into contact with or face each other with a slight distance, and thus the joint L2 of the soft laminate material 2a is constituted on the accommodation portion 25.　The joint L1 of the soft laminate material 2a is preferably provided at the center or at approximately the center of the main surface (that is, the main surface of the battery element 2) of the battery.

As illustrated in Fig. 6C, on the protruding surface 2S on the rear side of the bottom surface of the accommodation portion 25, the bonding regions 2Ra and 2Rb overlap each other, and the bonding layer 26a of the soft laminate material 2a and the bonding layer 26b of the hard laminate material 2b, which are disposed so as to face each other, are bonded to each other through thermal welding and the like.　In addition, on the protruding surface 2S on the rear side of the bottom surface of the accommodation portion 25, the surface protective layer 28a of the soft laminate material 2a that constitutes the protruding surface 2S, and the surface protective layer 28a on both ends of the soft laminate material 2a that is folded back are bonded through the thermal-welding sheet 25a by thermal welding and the like.

It is preferable that one end or both ends of the set of

sides

23b and 24b which are included in the joint L1 of the exterior packaging material 2 have a nonangular shape.　In addition, it is preferable that one end or both ends of the set of

sides

23a and 24a which are included in the joint L2 of the exterior packaging material 2 have a nonangular shape.　For example, as the nonangular shape, a curved shape such as an R shape or an approximately R shape, and a chamfered shape such as a C shape may be exemplified, but there is no limitation thereto.　Here, it is assumed that the R shape includes not only an arc shape but also an elliptical arc shape.　The C shape represents a shape obtained by cutting out a right-angle corner into a linear shape.

Label

For example, the label 6 is a name plate for displaying characters, a design, and the like, and more particularly, information regarding handling and safety standards, and the like on a surface of the exterior packaging material 2.　The label 6 includes a base material having a film shape, an adhesive layer, an ink layer, and a UV coating layer which are sequentially laminated on a main surface on one side of the base material, and an adhesive layer that is laminated on a main surface on the other side.　As the base material, for example, a PET base material that contains polyethylene terephthalate (PET) as a main component may be used.　However, there is no particular limitation thereto, and the base material may be appropriately selected in accordance with desired characteristics of the label 6.　The label 6 is bonded to the exterior packaging material 2 through the adhesive layer.　The label 6 may be provided to cover only one main surface of the battery on which the joint L1 is provided, or to cover the entirety of a peripheral surface of the battery.

Top Cover

The top cover 3 is fitted into an opening on a top side of the exterior packaging material 2 to clog the opening on the top side.　As illustrated in Fig. 2, the top cover 3 includes a top cover main body 31, a circuit substrate 32, a positive electrode tab 33a, a negative electrode tab 33b, and a holder 34.

The positive electrode lead 5a that is led out from the battery element 1 is connected to the circuit substrate 32 through the positive electrode tab 33a.　The negative electrode lead 5b that is led out from the battery element 1 is connected to the circuit substrate 32 through the negative electrode tab 33b.　For example, a protective circuit including temperature protection elements such as a fuse, a heat-sensing resistive element (positive temperature coefficient: PTC), and a thermistor, an ID resistance for identification of the battery, and the like are mounted on the circuit substrate 32.　In addition, the protective circuit includes charging and discharging control field effect transistors (FET), and an integrated circuit (IC) that performs monitoring of the battery element 1 and control of the charging and discharging control FET.

The PTC is connected to the battery element 1 in series.　When a temperature of the battery element 1 becomes higher than a set temperature, the electric resistance of the PTC rapidly increases, and substantially blocks a current that flows to the battery element 1.　The fuse or the thermistor is also connected to the battery element 1 in series.　When the temperature of the battery element 1 becomes higher than the set temperature, the fuse or the thermistor cuts off the current that flows to the battery element 1.　For example, when a terminal voltage of the battery element 1 exceeds a predetermined voltage (for example, 4.3 V to 4.4 V), there is a possibility that an abnormal state such as thermal runaway may occur.　Accordingly, the protective circuit monitors the voltage of the battery element 1, and turns off a charging control FET when the voltage exceeds a predetermined voltage so as to prohibit charging.　When the terminal voltage of the battery element 1 is over-discharged to a voltage that is equal to or lower than a discharging prohibition voltage, and a voltage of a secondary battery reaches 0 V, there is a possibility that the battery element 1 enters an inner short-circuited state, and recharging may be difficult.　Accordingly, the protective circuit monitors the voltage of the battery element 1, and when the voltage is equal to or lower than the discharging prohibition voltage, the protective circuit turns off a discharging control FET to prohibit discharging.

As illustrated in Fig. 7A, the top cover main body 31 has a front surface S11, a rear surface S12 that is opposite to the front surface S11, and a peripheral surface S13 between the front surface S11 and the rear surface S12.

The front surface S11 constitutes an end surface (elevation surface) on a top side of the battery in a state in which the top cover 3 is fitted into an opening on a top side of the exterior packaging material 2.　As illustrated in Fig. 2 and Fig. 7A, the front surface S11 of the top cover main body 31 has approximately the same shape as that of the opening on the top side of the exterior packaging material 2.　More specifically, the front surface S11 of the top cover main body 31 has a shape in which both elongated rectangular short sides are curved to form, for example, an elliptical arc toward the outside.

The rear surface S12 faces the top side of the battery element 1 in a state in which the top cover main body 31 is fitted into the opening on the top side of the exterior packaging material 2.　As illustrated in Fig. 7B, an accommodation portion 31a is provided in the rear surface S12.　The circuit substrate 32, the positive electrode tab 33a, the negative electrode tab 33b, and the like are accommodated in the accommodation portion 31a.　These components which are accommodated are retained inside the accommodation portion 31a of the top cover main body 31 by fitting the holder 34 into the top cover main body 31.

The peripheral surface S13 is a surface that is fitted into the opening on the top side of the exterior packaging material 2, and faces and comes into close contact with an inner peripheral surface on a top side of the exterior packaging material 2 in a state in which the top cover main body 31 is fitted into the opening on the top side of the exterior packaging material 2.　As illustrated in Fig. 7B, the peripheral surface S13 of the top cover main body 31 has a set of long surfaces S131 and S132 which have the same length as each other, and a set of short surfaces S133 and S134 which are provided on both ends of the long surfaces S131 and S132 and have the same length as each other.　The length of the long surfaces S131 and S132 in a peripheral direction of the peripheral surface S13 is longer than the length of the short surfaces S133 and S134 in the peripheral direction of the peripheral surface S13.

For example, the long surfaces S131 and S132 are flat surfaces or approximately flat surfaces, and are located on a main surface side of the battery in a state in which the top cover main body 31 is fitted into the opening on the top side of the exterior packaging material 2.　For example, the short surfaces S133 and S134 are curved surfaces which are curved in a convex shape, and are located on a side-surface side of the battery in a state in which the top cover main body 31 is fitted into the opening on the top side of the exterior packaging material 2.　The boundary between the long surfaces S131 and S132 and the short surfaces S133 and S134 is located at a position at which the shape of a surface varies, for example, a position at which the shape varies from a flat surface or an approximately flat surface to a curved surface.

As illustrated in Figs. 7A and 7B, the top cover main body 31 has a concave portion 3a in the long surface S131, which faces the joints L1 and L2 of the exterior packaging material 2, of the peripheral surface S13.　It is preferable that the concave portion 3a is provided at the center or approximately the center of the long surface S131.　For example, the concave portion 3a is a groove that extends in a thickness direction (that is, a width direction of the peripheral surface S13) of the top cover main body 31.　It is preferable that the groove penetrates through the top cover main body 31 in the thickness direction thereof.　When cutting the top cover main body 31 in a direction perpendicular to the thickness direction of the top cover main body 31 (a direction perpendicular to the width direction of the peripheral surface S13), a cross-sectional shape of the concave portion 3a is, for example, a V shape.

It is preferable that the joint L1 of the hard laminate material 2b is provided at a position that faces the concave portion 3a as illustrated in Fig. 8A, or at a position that approximately faces the concave portion 3a as illustrated in Fig. 8B.　The reason for the preference is as follows.　When the battery is bent with the concave portion 3a set as the center, it is possible to suppress the hard laminate material 2b from being bent, and to suppress the bent portion from piercing the battery element 1.

Here, the position that approximately faces the concave portion 3a represents a position in a range of -10% to +10% of a battery width D (position in a range of -D<m>*0.1 to +D<m>*0.1) (refer to Fig. 5) of the battery in a longitudinal direction of the long surface S131 with a position P1 of the concave portion 3a set as a reference.　For example, when the battery width D is 30 mm, the position that approximately faces the concave portion 3a represents a position in a range of -3 mm to +3 mm in a longitudinal direction of the long surface S131 with the position P1 of the concave portion 3a set as a reference.　In addition, the position P1 of the concave portion 3a represents the deepest position of the concave portion 3a.　In a case where the

short sides

23b and 24b of the hard laminate material 2b are disposed with a slight distance therebetween, a position P2 of the joint L1 of the hard laminate material 2b is set to an intermediate position between the

short sides

23b and 24b.

As illustrated in Figs. 7A and 7B, the top cover main body 31 has

concave portions

3m and 3n at portions between the long surface S131 on one side and the short surfaces S133 and S134 on both sides of the long surface S131, respectively.　On the other hand, as illustrated in Figs. 2 and 5, the exterior packaging material 2 has notched

portions

2m and 2n on both ends of the opening on the top side of the exterior packaging material 2.　In a state in which the top cover 3 is fitted into the opening on the top side of the exterior packaging material 2, the notched

portions

2m and 2n of the exterior packaging material 2 are positioned on the

concave portions

3m and 3n of the top cover main body 31, respectively.　According to this, the

concave portions

3m and 3n of the top cover main body 31 are exposed from the exterior packaging material 2 through the notched

portions

2m and 2n.　The

concave portions

3m and 3n are used on an apparatus side, to which the battery is loaded, to prevent reverse loading of positive and negative electrodes of the battery.

The shape of the

concave portions

3m and 3n which are provided on both sides of the long surface S131 of the top cover main body 31 is not particularly limited.　However, it is preferable that the shape is set to a shape in consideration of the degree of freedom on an apparatus side, and examples of the shape include a concave shape such as a step shape that slopes downward toward the longitudinal direction of the long surface S131.

Bottom Cover

The bottom cover 4 is fitted into an opening on a bottom side of the exterior packaging material 2 so as to clog the opening on the bottom side.　As illustrated in Fig. 9A, the bottom cover 4 includes a cover portion 41 and a fitting portion 42.　The cover portion 41 has a front surface S21 and a rear surface S22 that is opposite to the front surface S21.　The front surface S21 constitutes an end surface (rear surface) on the bottom side of the battery in a state in which the bottom cover 4 is fitted into the opening on the bottom side of the exterior packaging material 2.

The front surface S21 of the cover portion 41 has approximately the same shape as the opening on the bottom side of the exterior packaging material 2.　More specifically, the front surface S21 of the bottom cover 4 has a shape in which both elongated rectangular short sides are curved to form, for example, an elliptical arc toward the outside.　The rear surface S22 faces a bottom side of the battery element 1 in a state in which the bottom cover 4 is fitted into the opening on the bottom side of the exterior packaging material 2.

The fitting portion 42 is provided in the rear surface S22.　The fitting portion 42 has a peripheral surface S23.　The peripheral surface S23 is a surface that is fitted into the opening on the bottom side of the exterior packaging material 2, and faces and comes into close contact with an inner peripheral surface on a bottom side of the exterior packaging material 2 in a state in which the bottom cover 4 is fitted into the opening on the bottom side of the exterior packaging material 2.

A peripheral portion of the cover portion 41 slightly protrudes from the peripheral surface S23 of the fitting portion 42.　The protrusion width is selected to be approximately the same as the thickness of the exterior packaging material 2.　According to this, in a state in which the bottom cover 4 is fitted into the opening on the bottom side of the exterior packaging material 2, the cover portion 41 covers the opening on the bottom side, and the peripheral portion of the cover portion 41 and the peripheral surface of the exterior packaging material 2 are connected to each other in an approximately flat shape with no step difference therebetween.　The peripheral portion of the cover portion 41 may continuously protrude over the entirety of one round of the peripheral surface S23 of the fitting portion 42, and may protrude over a part of the one round.

As illustrated in Fig. 9B, the peripheral surface S23 of the fitting portion 42 has a pair of long surfaces S231 and S232 which have the same length as each other, and a pair of short surfaces S233 and S234 which are provided on both ends of the long surfaces S231 and S232 and have the same length as each other.　The length of the long surfaces S231 and S232 in a peripheral direction of the peripheral surface S23 is longer than the length of the short surfaces S233 and S234 in the peripheral direction of the peripheral surface S23.

For example, the long surfaces S231 and S232 are flat surfaces or approximately flat surfaces, and are located on a main surface side of the battery in a state in which the bottom cover 4 is fitted into the opening on the bottom side of the exterior packaging material 2.　For example, the short surfaces S233 and S234 are curved surfaces which are curved in a convex shape, and are located on a side-surface side of the battery in a state in which the bottom cover 4 is fitted into the opening on the bottom side of the exterior packaging material 2.　The boundary between the long surfaces S231 and S232 and the short surface S233 and S234 is located at a position at which a shape of a surface varies, for example, a position at which the shape varies from a flat surface or an approximately flat surface to a curved surface.

As illustrated in Figs. 9A and 9B, the bottom cover 4 has a concave portion 4a in the long surface S231, which faces the joints L1 and L2 of the exterior packaging material 2, of the peripheral surface S23.　It is preferable that the concave portion 4a is provided at the center or approximately the center of the long surface S231.　For example, the concave portion 4a is a groove that extends in the thickness direction (that is, a width direction of the peripheral surface S23) of the bottom cover 4.　It is preferable that the groove penetrates through the bottom cover 4 in the thickness direction thereof.　When cutting the bottom cover 4 in a direction perpendicular to the thickness direction of the bottom cover 4 (a direction perpendicular to the width direction of the peripheral surface S23), a cross-sectional shape of the concave portion 4a is, for example, a V shape.　It is preferable that the joint L1 of the hard laminate material 2b is provided at a position that faces the concave portion 4a, or at a position that approximately faces the concave portion 4a.

In addition, the bottom cover 4 is provided with one or more, and preferably, two or more penetration holes (not illustrated) which penetrate the bottom cover 4 from a surface on one side facing the battery element 1 to an opposite surface.　In a case where two or more penetration holes are provided, at least one of the penetration holes can be used to release air from a space between the battery element 1 and the bottom cover 4 during resin injection, and thus it is possible to improve resin filling properties.
(1.2　Method of Manufacturing Battery)

Next, an example of a method of manufacturing the battery according to the first embodiment of the present disclosure will be described.

Process of Preparing Battery Element

First, for example, the positive electrode 11 and the negative electrode 12 in which the electrolyte layer 14 is formed on both surfaces thereof, and the separator 13 are sequentially laminated in the order of the negative electrode 12, the separator 13, the positive electrode 11, and the separator 13 to form a laminated body.　Next, the laminated body is wound around a flat plate core, and winding is performed plural times to prepare the wound-type battery element 1.

Process of Packaging Battery Element

Next, the accommodation portion 25 is formed in the soft laminate material 2a by a deep drawing process.　At this time, as illustrated in Fig. 4A, the accommodation portion 25 is formed at a position that slightly deviates from the central position of the soft laminate material 2a toward the short side 24a.　Next, the battery element 1 is accommodated in the accommodation portion 25 that is formed in the soft laminate material 2a.

Next, as illustrated in Fig. 4A, the hard laminate material 2b is disposed to overlap the soft laminate material 2a at a position deviating from each other in the longitudinal direction thereof.　According to this, the bonding region 2Ra in which only the soft laminate material 2a exists is formed at one end in the longitudinal direction of the soft laminate material 2a and the hard laminate material 2b which overlap each other, and the bonding region 2Rb in which only the hard laminate material 2b exists is formed at the other end.　In this manner, when the soft laminate material 2a is disposed to overlap the hard laminate material 2b in a positionally deviating manner, after both ends of the soft laminate material 2a and the hard laminate material 2b are folded toward the protruding surface 2S of the accommodation portion 25, the bonding layer 26a of the soft laminate material 2a and the bonding layer 26b of the hard laminate material 2b are bonded to each other with a certain extent of width.

Next, in a dispositional relationship as illustrated in Fig. 4A, the periphery of the accommodation portion 25 is thermally welded in a reduced-pressure atmosphere to seal the battery element 1.　At this time, the entirety of a portion at which the bonding layers 26a and 26b overlap each other may be thermally welded.　Next, as illustrated in Fig. 4A, the thermal-welding sheet 25a having a predetermined shape is provided to the protruding surface 2S on a rear side of the bottom surface of the accommodation portion 25.

Next, both ends of the soft laminate material 2a and the hard laminate material 2b, that is, the

short sides

23a and 24a and the

short sides

23b and 24b are folded toward the main surface of the battery element 1 which is covered with the soft laminate material 2a, that is, the protruding surface 2S on the rear side of the bottom surface of the accommodation portion 25.　Next, the bonding region 2Ra of the soft laminate material 2a and the bonding region 2Rb of the hard laminate material 2b are thermally welded, and the soft laminate material 2a is thermally welded to the protruding surface 2S on the rear side of the bottom surface of the accommodation portion 25 through the thermal-welding sheet 25a.　According to this, as illustrated in Fig. 5, the soft laminate material 2a and the hard laminate material 2b are fixed in a state of wrapping and closing the accommodation portion 25 in which the battery element 1 is accommodated, and thus the opening on the top side and the opening on the bottom side are formed.

As illustrated in Fig. 6C, in a state of wrapping the battery element 1, the

short sides

23b and 24b of the hard laminate material 2b are disposed to come into contact with each other, or to face each other with a slight distance, and thus the joint L1 is formed.　In addition, on an inner side of the hard laminate material 2b, the

short sides

23a and 24a of the soft laminate material 2a are disposed to come into contact with each other or to face each other with a slight distance, and thus the joint L2 is formed.　In addition, the joint L2 is not limited to the above-described example, and the

short sides

23a and 24a of the soft laminate material 2a may be disposed to face each other with a certain extent of distance.

Fitting Process of Top Cover

Next, the positive electrode lead 5a and the negative electrode lead 5b are attached to the circuit substrate 32 through the positive electrode tab 33a and the negative electrode tab 33b, for example, through resistance welding or ultrasonic welding.　Next, the circuit substrate 32, the positive electrode tab 33a, the negative electrode tab 33b, and the like are accommodated in the accommodation portion of the top cover main body 31, and then the holder 34 is fitted into the top cover main body 31.　According to this, the top cover 3 is formed.

Next, the top cover 3 is fitted into the opening on the top side of the exterior packaging material 2 in such a manner than the joint L1 of the exterior packaging material 2 faces the concave portion 3a of the top cover main body 31 while appropriately folding back the positive electrode lead 5a and the negative electrode lead 5b.

Fitting Process of Bottom Cover

Next, the bottom cover 4 is fitted into the opening on the bottom side of the exterior packaging material 2 in such a manner that the joint L1 of the exterior packaging material 2 faces the concave portion 4a of the bottom cover 4.

Thermal Welding Process

Next, the exterior packaging material 2 is pressed with a jig over the entirety length thereof to perform thermal welding of the exterior packaging material 2. Specifically, a heater block that is configured of a metal such as copper is pressed to the end on the top side of the exterior packaging material 2 or the vicinity of the end on the top side from upper and lower sides to thermally weld the peripheral surface of the top cover main body 31 and the bonding layer 26b (the bonding layer 26b of the bonding region Rc) on the inner surface side of the hard laminate material 2b.　In addition, similarly, the heater block may be pressed to the end on the bottom side of the exterior packaging material 2 or the vicinity of the end on the bottom side from upper and lower sides to thermally weld the peripheral surface of the bottom cover 4 and the bonding layer 26b on an inner surface side of the hard laminate material 2b.

Resin Injection Process

Next, a space between the end surface on the bottom side of the battery element 1 and the bottom cover 4 is filled with a molten resin through a penetration hole (not illustrated), and then the molten resin is solidified.　According to this, the bottom cover 4 is bonded to the end surface of the battery element 1.　In addition, the filling resin is not particularly limited as long as the filling resin is in a low-viscosity state during casting.　For example, polyimide-based hot melt, polyolefin-based hot melt, nylon, polypropylene (PP), polycarbonate (PC), acrylonitrile-butadiene-styrene copolymerization resin (ABS resin), and the like may be used.

In addition, a space between the top cover 3 and the end surface on the top side of the battery element 1 may be filled with the molten resin.　In this case, one or more penetration holes may be provided to the top cover 3, and the molten resin may be injected through the penetration holes.

According to the above-described processes, a target battery is manufactured.
(1.3　Effect)

In the battery according to the first embodiment, the top cover 3 and the bottom cover 4 have a concave portion in a surface that faces the joint L1 of the exterior packaging material 2, and the joint L1 is located at a position that faces or approximately faces the concave portion 3a and the concave portion 4a.　According to this, when a large load is applied to the battery, it is possible to control a bending direction of the battery in such a manner that the battery is bent with a battery main surface including the joint L1 set as an inner side.　In addition, it is possible to control a bending position of the battery in such a manner that the battery is bent with the position of the joint L1 or approximately the joint L1 set as a boundary.　Accordingly, it is possible to suppress a sharp portion, which occurs when the exterior packaging material 2 is bent, from piercing the battery element 1.　That is, occurrence of short-circuiting of the battery is suppressed, and thus it is possible to improve stability of the battery.

In a case where one end or both ends of the set of

sides

23b and 24b which are included in the joint L1 of the exterior packaging material 1 have an nonangular shape, even when a large load is applied to the battery, and the battery is bent, it is possible to suppress the one end or the both ends of the

sides

23b and 24b from piercing the battery element 1.　In addition, in a case where one end or both ends of the set of

sides

23a and 24a which are included in the joint L2 of the exterior packaging material 1 have a nonangular shape, it is also possible to suppress the piercing.

The soft laminate material 2a that constitutes the protruding surface 2S of the accommodation portion 25 is provided below the joints L1 and L2 of the exterior packaging material 2.　Accordingly, in a case where the battery is bent with a battery main surface including the joints L1 and L2 of the exterior packaging material 2 set as an inner side, it is possible to protect the battery element 1 from the

short sides

23b and 24b of the hard laminate material 2b, the

short sides

23a and 24a of the soft laminate material 2a, and corners on both ends thereof.
(1.4　Modification Example)

In the above-described first embodiment, description has been given to an example in which when cutting the top cover 3 in a direction perpendicular to a thickness direction of the top cover 3, a cross-sectional shape of the concave portion 3a is a V shape, and the like, but the cross-sectional shape is not limited to the example.　Examples of the cross-sectional shape other than the V shape include polygonal shapes such as a rectangular shape (refer to Fig. 10A) and a trapezoidal shape (refer to Fig. 10B), a U shape (refer to Fig. 10C), a partially circular shape such as a semicircular shape (refer to Fig. 10D), a partially elliptical shape such as a semielliptical shape, an irregular shape, and the like.　In addition, Figs. 10A to 10D illustrate an example in which the depth of the concave portion 3a is equal to or less than the half of the thickness of the top cover 3.　However, the depth of the concave portion 3a is not limited to the example, and the depth may exceed half of the thickness of the top cover 3 as shown in Fig. 10E.　As is the case with the above-described top cover 3, a cross-sectional shape other than the V shape may also be used for the bottom cover 4.　The shape of the concave portion 3a of the top cover 3 and the shape of the concave portion 4a of the bottom cover 4 may be different from each other.

As illustrated in Fig. 10F, the top cover 3 may be configured to have a hole 3b instead of the concave portion 3a.　In this case, for example, the hole 3b is provided at a position that is close to the long surface S131 in relation to the long surface S132, preferably, in the vicinity of the long surface S131.　It is preferable that the hole 3b is provided at the center of the long surface S131 or approximately the center thereof.　It is preferable that the joint L1 of the hard laminate material 2b is provided immediately over the hole 3b or approximately immediately over the hole 3b.　Examples of a cross-sectional shape of the hole 3b include polygonal shapes such as a circular shape and an elliptical shape, an irregular shape, and the like, but there is no limitation to the shapes.　As is the case with the top cover 3, the bottom cover 4 may be configured to have a hole instead of the concave portion 4a.　A shape of the hole of the top cover 3 and a shape of the hole of the bottom cover 4 may be different from each other.

The top cover 3 may be configured to have both the concave portion 3a and the hole 3b.　In this case, for example, the hole 3b is provided at a position that is immediately below the concave portion 3a or approximately immediately below the concave portion 3a.　As is the case with the top cover 3, the bottom cover 4 may be configured to have both the concave portion and the hole.　In addition, one of the top cover 3 and the bottom cover 4 may have the concave portion and the other may have the hole.
(2　Second Embodiment)

(2.1　Configuration of Electronic Apparatus)

As illustrated in Fig. 11, an electronic apparatus 400 according to a second embodiment of the present disclosure includes an electronic circuit 401 of an electronic apparatus main body, and a battery 300.　Here, description will be made with respect to a configuration in which the electronic apparatus 400 includes one battery 300 as an example, but the electronic apparatus 400 may be configured to include two or more batteries 300.　The battery 300 is electrically connected to the electronic circuit 401 through a positive electrode terminal 3h and a negative electrode terminal 3i.　For example, the electronic apparatus 400 has a configuration in which the battery 300 is detachable by a user.　In addition, the configuration of the electronic apparatus 400 is not limited thereto, and the electronic apparatus 400 may have a configuration in which the battery 300 is embedded in the electronic apparatus 400 in order for the battery 300 not to be separated from the electronic apparatus 400 by a user.

During charging of the battery 300, the positive electrode terminal 3h and the negative electrode terminal 3i of the battery 300 are connected to a positive electrode terminal and a negative electrode terminal of a charger (not illustrated), respectively.　On the other hand, during discharging of the battery 300 (during use of the electronic apparatus 400), the positive electrode terminal 3h and the negative electrode terminal 3i of the battery 300 are connected to a positive electrode terminal and a negative electrode terminal of the electronic circuit 401, respectively.

Examples of the electronic apparatus 400 include a note-type personal computer, a tablet-type computer, a cellular phone (for example, a smart phone, and the like), a personal digital assistant (PDA), an image capturing device (for example, a digital still camera, a digital video camera, and the like), an audio device (for example, a portable audio player), a gaming machine, a cordless phone extension, an electronic book, an electronic dictionary, a radio, a headphone, a navigation system, an electric tool, an electric shaver, a refrigerator, an air conditioner, a television, a stereo, a water heater, a microwave oven, a dishwasher, a washing machine, a dryer, an illumination apparatus, a toy, a medical instrument, a robot, and the like, but there is no limitation thereto.

Electronic Circuit

For example, the electronic circuit 401 includes a CPU, a peripheral logic unit, an interface unit, a storage unit, and the like, and controls the entirety of the electronic apparatus 400.

Battery

The battery 300 is the battery according to the above-described first embodiment or the modification example thereof.　The battery 300 includes a protective circuit 301, and the protective circuit 301 is a protective circuit that is provided to the circuit substrate 32 in the first embodiment.
(2.2　Effect)

The electronic apparatus 400 includes the battery according to the above-described first embodiment or the modification example thereof as the battery 300.　According to this, even when the electronic apparatus 400 is broken and the battery is bent, it is possible to prevent the battery from being short-circuited.　Accordingly, it is possible to improve the safety of the electronic apparatus 400.

Hereinafter, the present disclosure will be described in detail with reference to examples, but the present disclosure is not limited to the examples.

Example

(Process of Manufacturing Battery Element)

First, for example, a positive electrode and a negative electrode in which a gel electrolyte layer was formed on both surfaces thereof, and a separator were sequentially laminated in the order of the negative electrode, the separator, and the positive electrode, and the separator to form a laminated body.　Next, the laminated body was wound around a flat plate core, and winding was performed plural times in the longitudinal direction to prepare a wound-type battery element having a flat shape.

Exterior Packaging Process of Battery Element

First, as a soft laminate material, a rectangular soft aluminum laminate film (hereinafter, referred to as a "soft Al laminate film") having a laminated structure, in which a PP layer (adhesive layer), a soft aluminum layer (metal layer), and a nylon layer (surface protective layer) were sequentially laminated, was prepared.　Next, an accommodation portion was formed on the soft Al laminate film through a deep drawing process.　At this time, the accommodation portion was formed at a position that slightly deviated from the central position of the soft Al laminate film toward a short side on one side.　Next, a battery element was accommodated in the accommodation portion that was formed in the soft Al laminate film.

Next, as a hard laminate material, a rectangular hard aluminum laminate film (hereinafter, referred to as a "hard Al laminate film") having a laminated structure, in which a polypropylene layer (adhesive layer), a hard aluminum layer (metal layer), and a nylon layer (surface protective layer) were sequentially laminated, was prepared.　Next, the hard Al laminate film was disposed to overlap the soft Al laminate film at a position that slightly deviated in a longitudinal direction thereof.　According to this, a bonding region in which only the soft Al laminate film existed was formed at one end in the longitudinal direction of the Al laminate films which overlapped each other, and a bonding region in which only the hard Al laminate film existed was formed at the other end.

Next, the periphery of the accommodation portion was thermally welded in a reduced pressure atmosphere to seal the battery element.　Next, a thermal-welding sheet having a predetermined shape was provided on a protruding surface on a rear side of a bottom surface of the accommodation portion.　Next, both ends of the soft Al laminate film and the hard Al laminate film were folded toward a main surface of the battery element covered with the soft Al laminate film, that is, the protruding surface on the rear side of the bottom surface of the accommodation portion to overlap the polypropylene layers of the bonding regions on both ends. At this time, disposition was performed in such a manner that short sides of the hard Al laminate film come into contact with each other, thereby forming a joint of the hard Al laminate film at the center of the main surface of the battery element.　In addition, on an inner side of the hard Al laminate film, disposition was performed in such a manner that short sides of the soft Al laminate film come into contact with each other, thereby forming a joint of the soft Al laminate film at a position that slightly deviated from the center of the main surface of the battery element.

Next, polypropylene layers in the bonding regions of the soft Al laminate film and the hard Al laminate film were thermally welded.　In addition, a nylon layer of the soft Al laminate film that constituted the protruding surface on the rear side of the bottom surface of the accommodation portion, and a nylon layer on both ends of the Al laminate film that was folded back were thermally welded through the thermal-welding sheet.　According to this, the soft Al laminate film and the hard Al laminate film were fixed in a state of wrapping and closing the accommodation portion in which the battery element was accommodated, and thus an aluminum laminate film exterior packaging material (hereinafter, referred to as an "Al film exterior packaging material") having an opening on a top side and an opening on a bottom side was formed.
<Fitting Process of Top Cover>

Next, a positive electrode lead and a negative electrode lead were attached to a circuit substrate through a positive electrode tap and a negative electrode tap, respectively, through ultrasonic welding.　Next, a top cover main body, in which a groove having a V-shaped cross-section was provided at the center of a long surface, was prepared, and the circuit substrate, the positive electrode tap, and the negative electrode tap were accommodated in an accommodation portion of the top cover main body.　Then, a holder was fitted into the top cover main body.　According to this, a top cover was formed.

Next, the top cover was fitted into the opening on the top side of the Al film exterior packaging material in such a manner that the joint of the hard Al laminate film faced the groove having the V-shaped cross-section while appropriately folding back the positive electrode lead and the negative electrode lead.
<Fitting Process of Bottom Cover>

Next, a bottom cover in which a groove having a V-shaped cross-section was provided at the center of a long surface, was prepared, and the bottom cover was fitted into the opening on the bottom side of the Al film exterior packaging material in such a manner that the joint of the hard Al laminate film faced the groove having the V-shaped cross-section.
<Thermal Welding Process>

Next, a heater block was pressed to the end on the top side of the Al film exterior packaging material from upper and lower sides to thermally weld the peripheral surface of the top cover main body and the PP layer on an inner side of the hard Al laminate film.
<Resin Injection Process>

Next, a space between the battery element and the bottom cover was filled with a molten resin through a penetration hole of the bottom cover, and then the molten resin was solidified.　According to this, the bottom cover 4 was bonded to an end surface on the bottom side of the battery element.　Through the above-described processes, a target battery was obtained.
(Comparative Example)

A top cover and a bottom cover, in which a groove having a V-shaped cross-section was provided at the center of a long surface opposite to the long surface in Example, were prepared.　The top cover and the bottom cover were fitted into the opening on the top side and the opening on the bottom side of the Al film exterior packaging material, respectively, in such a manner that the groove having the V-shaped cross-section was located at a main surface side opposite to a main surface side provided with the joint in both main surfaces of the battery.　A battery was obtained in the same manner as Example except for the above-described configuration.

Vertical Collapse Test

A force was applied from both side surfaces of each of the batteries of Example and Comparative Example, which were obtained as described above, to the center thereof to perform a vertical collapse test.　The result is shown in Table 1.

Results of the vertical collapse test battery packs of Example and Comparative Example are shown.

From Table 1, it can be seen as follows.

When the top cover has the groove at the center of the long surface that faces the joint of the exterior packaging material, it is possible to control a bending direction of the battery in such a manner that the battery is bent with the battery main surface including the joint set as an inner side.

When the top cover has the groove at the center of the long surface opposite to the long surface that faces the joint of the exterior packaging material, it is possible to control the bending direction of the battery in such a manner that the battery is bent with the battery main surface opposite to the battery main surface including the joint set as an inner side.

When the top cover has the groove at the center of the long surface that faces the joint of the exterior packaging material, and the exterior packaging material has the joint at a position that faces the groove, it is possible to suppress occurrence of short-circuiting.

Hereinbefore, the embodiment of the present disclosure, the modification example thereof, the examples have been described in detail.　However, the present disclosure is not limited to the embodiment, the modification example, and the examples, and various modifications can be made on the basis of the technical sprit of the present disclosure.

For example, the configurations, the methods, the processes, the shapes, the materials, the dimensions, and the like, which are exemplified in the embodiment, the modification example thereof, and the examples are illustrative only, and different configurations, methods, processes, shapes, materials, dimensions, and the like may be used as necessary.

In addition, the configurations, the methods, the processes, the shapes, the materials, the dimensions, and the like of the embodiment, the modification example thereof, and the examples may be combined with each other in a range not departing from the gist of the present disclosure.

In addition, in the embodiment, the modification example thereof, and the examples, description has been given to an example in which the present disclosure is applied to the battery having the wound structure.　However, the structure of the battery is not limited thereto, and the present disclosure is also applicable to a battery having a structure in which the positive electrode and the negative electrode are folded, a structure in which the positive electrode and the negative electrode are stacked, and the like.

In addition, in the embodiment, the modification example thereof, and the examples, description has been given to a case in which the battery element is a lithium ion secondary battery as an example.　However, the battery element is not limited to this example, and the present disclosure is also applicable to a secondary battery, a primary battery, and the like other than the lithium ion secondary battery.

In addition, in the embodiment, the modification example, and the examples, description has been given to an example in which the battery and the battery element have a flat shape.　However, the shape of the battery and the battery element is not limited to the flat shape, and the present disclosure is also applicable to a battery having an angular shape.

In addition, in the embodiment, the modification example thereof, and the examples, a description has been given to an example in which the present disclosure is applied to the battery that includes a nonaqueous electrolytic solution as an electrolyte, and a polymeric compound serving as a support body that supports the nonaqueous electrolytic solution, but the electrolyte is not limited to this example.　For example, the present disclosure is also applicable to a battery including an electrolytic solution such as a nonaqueous electrolytic solution as an electrolyte, and a battery including a solid electrolyte containing an electrolyte salt as an electrolyte.

In addition, in the embodiment, the modification example, and the examples, description has been given to a configuration in which the exterior packaging materials has the opening on the top side and the opening on the bottom side, and the top cover and the bottom cover are fitted into the openings, respectively.　However, the configuration of the battery is not limited thereto.　For example, the present disclosure is also applicable to a battery having a configuration in which the exterior packaging material has only either the opening on the top side or the opening on the bottom side, and a cover is fitted into the opening.

In addition, in the embodiment, the modification example thereof, and the examples, description has been given to a configuration in which the battery includes two exterior packaging materials including the soft laminate material (first exterior packaging material) and the hard laminate material (second exterior packaging material), but the configuration of the battery is not limited thereto.　For example, the present disclosure is also applicable to a battery including only one exterior packaging material, or a battery including three or more exterior packaging materials.　In addition, in a case where the battery includes three or more exterior packaging materials, and three or more joints of the exterior packaging materials are provided, it is preferable that the concave portion is provided at a position that faces or approximately faces a joint of the hard exterior packaging material among the three or more exterior packaging materials.

In addition, the present disclose may employ the following configurations.
(1)
A battery comprising:
a battery element ;
an external packaging element that covers opposed main surfaces of the battery element, and that has openings at opposed first and second end surfaces of the battery element; and
first and second cover bodies that cover the end surfaces of the battery element, at least one of the cover bodies including a concave portion.
(2)
A battery according to (1), wherein the external packaging element includes at least one　rounded corner.
(3)
A battery according to any one of (1) to (2), wherein the external packaging element includes edges meeting at a joint that extends along one of the main surfaces of the battery element.
(4)
A battery according to (3), wherein the joint is located within 3 mm from a center line of the respective main surface of the battery element.
(5)
A battery according to any one of (3) and (4), wherein the concave portion is adjacent to the joint of the external packaging element.
(6)
A battery according to (5), wherein the external packaging element includes a first exterior packaging material layer, and a second external packaging material layer that is the layer having the edges forming the joint adjacent to the concave portion.
(7)
A battery according to (6), wherein the second external packaging material layer is harder relative to the first external packaging material layer.
(8)
A battery according to (6), wherein first external packaging material layer has edges forming a second joint, and the second joint of the first external packaging material layer and the joint of the second external material packaging layer are offset from one another in a direction orthogonal to extending directions of the joints.
(9) 　
A battery according to (6), wherein the first exterior packaging material layer includes a recessed accommodation portion in which the battery element is housed.
(10) 　
A battery according to (9), further comprising a thermal-welding sheet provided on an exterior protruding surface of the accommodation portion.
(11) 　
A battery according to any one of (6) to (10), wherein each of the first and second external packaging material layers have a laminated structure including a resin　layer, a metal layer, and a surface　layer.
(12)
A battery according to any one of (1) to (11), wherein the concave portion has a shape selected from the group consisting of a V shape, a rectangular shape, a trapezoidal shape, a U shape, a semi-circular shape, and a semi-elliptical shape.
(13)
A battery according to any one of (1) to (12), wherein a depth of the concave portion is less than half of a thickness of the cover body.
(14)
A battery according to any one of (1) to (12), wherein a depth of the concave portion is greater than or equal to half of a thickness of the cover body.
(15)
A battery according to any one of (1) to (14), wherein the concave portion is provided at approximately the center of a long side of the cover body.
(16)
A battery according to any one of (1) to (15), wherein the concave portion is a recess formed into a long side edge of the cover body.
(17)
A battery according to any one of (1) to (15), wherein the concave portion is a hole that is provided at approximately the center of a long side surface of the cover body.
(18)
An electronic apparatus comprising:
a battery including
a battery element,
an external packaging element that covers opposed main surfaces of the battery element, and that has openings at opposed first and second opposed end surfaces of the battery element, and
first and second cover bodies that cover the end surfaces of the battery element at least one of the cover bodies including a concave portion.
(19) A battery including: a battery element; an exterior packaging material that packages the battery element and has an opening; and a cover body that is provided in the opening, wherein the cover body has a concave portion in a surface that faces a joint of the exterior packaging material, and the joint is formed at a position that faces the concave portion or a position that approximately faces the concave portion.
(20) A battery including: a battery element; an exterior packaging material that accommodates the battery element and has a first opening and a second opening; a first cover body that is provided in the first opening; and a second cover body that is provided in the second opening, wherein at least one of the first cover body and the second cover body has a concave portion in a surface that faces a joint of the exterior packaging material, and the joint is located at a position that faces the concave portion or a position that approximately faces the concave portion.
(21) The battery according to (19) or (20), wherein the concave portion is provided at the center of the surface.
(22) The battery according to any one of (19) to (21), wherein one end or both ends of a set of sides, which are included in the joint of the exterior packaging material, have a nonangular shape.
(23) The battery according to any one of (19) to (22), wherein the exterior packaging material includes a first exterior packaging material and a second exterior packaging material that is disposed to overlap the first exterior packaging material, and both ends of the second exterior packaging material are joined together on a main surface of the battery element to constitute the joint.
(24) The battery according to any one of (19) to (23), wherein the exterior packaging material includes a first exterior packaging material and a second exterior packaging material that is disposed to overlap the first exterior packaging material in a deviating manner, deviating portions of the first exterior packaging material and the second exterior packaging material overlap each other on a main surface of the battery element to constitute a joint of the first exterior packaging material and a joint of the second exterior packaging material, and the joint of the exterior packaging material is the joint of the second exterior packaging material.
(25) The battery according to (23) or (24), wherein the second exterior packaging material is harder than the first exterior packaging material.
(26) The battery according to any one of (19) to (25), wherein the exterior packaging material is a laminate film.
(27) The battery according to any one of (19) to (26), wherein the battery element has a flat shape or a square shape, and the joint is provided on a main surface of the battery element.
(28) An electronic apparatus including: the battery according to any one of (19) to (27), wherein power is supplied from the battery.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

1 Battery element
2 Exterior packaging material
2a Soft laminate material
2b Hard laminate material
3 Top cover
3a, 4a Concave portion
3b Hole portion
4 Bottom cover
5a Positive electrode lead
5b Negative electrode lead
6 Label
L1, L2 Joint
S13, S23 Peripheral surface
S131, S132, S231, S232 Long surface
S133, S134, S233, S234 Short surface

Claims

　A battery comprising:
a battery element ;
an external packaging element that covers opposed main surfaces of the battery element, and that has openings at opposed first and second end surfaces of the battery element; and
first and second cover bodies that cover the end surfaces of the battery element, at least one of the cover bodies including a concave portion.
A battery according to Claim 1, wherein the external packaging element includes at least one　rounded corner.
A battery according to Claim 1, wherein the external packaging element includes edges meeting at a joint that extends along one of the main surfaces of the battery element.
A battery according to Claim 3, wherein the joint is located within 3 mm from a center line of the respective main surface of the battery element.
A battery according to Claim 4, wherein the concave portion is adjacent to the joint of the external packaging element.
A battery according to Claim 5, wherein the external packaging element includes a first exterior packaging material layer, and a second external packaging material layer that is the layer having the edges forming the joint adjacent to the concave portion.
A battery according to Claim 6, wherein the second external packaging material layer is harder relative to the first external packaging material layer.
A battery according to Claim 6, wherein first external packaging material layer has edges forming a second joint, and the second joint of the first external packaging material layer and the joint of the second external material packaging layer are offset from one another in a direction orthogonal to extending directions of the joints.
A battery according to Claim 6, wherein the first exterior packaging material layer includes a recessed accommodation portion in which the battery element is housed.
A battery according to Claim 9, further comprising a thermal-welding sheet provided on an exterior protruding surface of the accommodation portion.
A battery according to Claim 6, wherein each of the first and second external packaging material layers have a laminated structure including a resin　layer, a metal layer, and a surface　layer.
A battery according to Claim 1, wherein the concave portion has a shape selected from the group consisting of a V shape, a rectangular shape, a trapezoidal shape, a U shape, a semi-circular shape, and a semi-elliptical shape.
A battery according to Claim 1, wherein a depth of the concave portion is less than half of a thickness of the cover body.
A battery according to Claim 1, wherein a depth of the concave portion is greater than or equal to half of a thickness of the cover body.
A battery according to Claim 1, wherein the concave portion is provided at approximately the center of a long side of the cover body.
A battery according to Claim 1, wherein the concave portion is a recess formed into a long side edge of the cover body.
A battery according to Claim 1, wherein the concave portion is a hole that is provided at approximately the center of a long side surface of the cover body.
An electronic apparatus comprising:
a battery including
a battery element,
an external packaging element that covers opposed main surfaces of the battery element, and that has openings at opposed first and second opposed end surfaces of the battery element, and
first and second cover bodies that cover the end surfaces of the battery element at least one of the cover bodies including a concave portion.