JP2012238508A - Nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a constitution of a nonaqueous secondary battery excellent in load characteristics.SOLUTION: A nonaqueous secondary battery comprises: a negative electrode 14 having a flat sheet-shaped surface on which an irregularity portion is formed; a separator 15 arranged to follow the surface having the irregularity portion of the negative electrode 14; and a sheet-shaped positive electrode 13 having a surface area smaller than that of the negative electrode 14 and having a surface fitting to irregularities formed by the separator 15. The negative electrode 14 and the positive electrode 13 face with each other so that charge/discharge can be performed in a lamination direction and also in a direction perpendicular to the lamination direction.

Description

  The present invention relates to a non-aqueous secondary battery, and more particularly to a stacked non-aqueous secondary battery.

  Non-aqueous secondary batteries are used as batteries with high energy density. In applications such as in-vehicle use and industrial use, high load characteristics (input / output characteristics) are required in addition to high energy density.

  In Japanese Patent Application Laid-Open No. 2010-118164, irregularities are formed on the surface of the current collector, and an electrode material layer (electrode mixture layer) is filled in the concave portions of the current collector, An electrode of a secondary battery is disclosed that is formed by a second electrode material that extends over the entire surface of the current collector so as to cover the first electrode material.

  The electrode of this secondary battery has improved the adhesion between the current collector and the electrode material layer by forming irregularities on the surface of the current collector. The first electrode material has a lower electrical resistance than the second electrode material, thereby improving the reactivity at the interface between the current collector and the electrode material layer.

JP 2010-118164 A

  In the electrode reaction of the nonaqueous secondary battery, the diffusion of the active material inside the electrode mixture layer is considered to be a rate-limiting process. Therefore, there is a limit to improving the load characteristics by the electrode of the secondary battery described in the above-mentioned document.

  The objective of this invention is obtaining the structure of the non-aqueous secondary battery excellent in the load characteristic.

  The non-aqueous secondary battery disclosed in the present invention includes a negative electrode having a concavo-convex portion formed on a flat sheet-shaped surface, a separator disposed along the surface having the concavo-convex portion of the negative electrode, and the negative electrode. A sheet-like positive electrode having a small surface area and having a surface that fits into the irregularities formed by the separator. The negative electrode and the positive electrode face each other so as to be able to charge and discharge in the stacking direction, and face each other so as to be able to charge and discharge also in a direction perpendicular to the stacking direction.

  According to said structure, the said negative electrode and the said positive electrode are facing also in the direction perpendicular | vertical to a lamination direction while facing in the lamination direction. Therefore, in addition to the stacking direction, the active material can be exchanged in a direction perpendicular thereto. The reaction rate is proportional to the area of the electrode. Therefore, the load characteristics can be improved by the amount of the area facing each other in the direction perpendicular to the stacking direction.

  In addition, according to said structure, the said negative electrode and the said positive electrode fit through a separator. Therefore, the position regulation between the negative electrode and the positive electrode can be accurately performed without using a special jig or apparatus. In addition, it is difficult for deviation to occur after the lamination.

  According to the present invention, a configuration of a non-aqueous secondary battery having excellent load characteristics can be obtained.

FIG. 1 is a front view showing a schematic configuration of a nonaqueous secondary battery according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4A is an exploded perspective view showing a set of positive electrodes, negative electrodes, and separators extracted from the nonaqueous secondary battery according to one embodiment of the present invention. FIG. 4B is a perspective view showing a set of positive electrodes, negative electrodes, and separators extracted from the nonaqueous secondary battery according to the embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4B. FIG. 6 is an enlarged view of FIG. FIG. 7 is a diagram conceptually showing the exchange of active materials in the nonaqueous secondary battery according to one embodiment of the present invention. . FIG. 8A is a diagram showing one step in a method for producing a negative electrode for a nonaqueous secondary battery according to an embodiment of the present invention. FIG. 8B is a diagram showing one step of a method for producing a negative electrode for a nonaqueous secondary battery according to an embodiment of the present invention. FIG. 8C is a diagram showing one step in a method for producing a negative electrode for a nonaqueous secondary battery according to an embodiment of the present invention. FIG. 9A is an exploded perspective view showing a set of a positive electrode, a negative electrode, and a separator extracted from the nonaqueous secondary battery according to the first modification of the present invention. FIG. 9B is a cross-sectional view showing a set of a positive electrode, a negative electrode, and a separator extracted from the nonaqueous secondary battery according to the first modification of the present invention. FIG. 10A is a cross-sectional view showing a set of a positive electrode, a negative electrode, and a separator extracted from a nonaqueous secondary battery according to a second modification of the present invention. FIG. 10B is a cross-sectional view showing a set of a positive electrode, a negative electrode, and a separator extracted from a nonaqueous secondary battery according to a third modification of the present invention. FIG. 10C is a cross-sectional view showing a set of a positive electrode, a negative electrode, and a separator extracted from a nonaqueous secondary battery according to a fourth modification of the present invention. FIG. 10D is a cross-sectional view showing a set of a positive electrode, a negative electrode, and a separator extracted from a nonaqueous secondary battery according to a fifth modification of the present invention. FIG. 10E is a cross-sectional view showing a set of a positive electrode, a negative electrode, and a separator extracted from a nonaqueous secondary battery according to a sixth modification of the present invention. FIG. 10F is a cross-sectional view showing a set of a positive electrode, a negative electrode, and a separator extracted from a nonaqueous secondary battery according to a seventh modification of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Configuration of non-aqueous secondary battery]
FIG. 1 is a front view showing a schematic configuration of a nonaqueous secondary battery 10 according to an embodiment of the present invention. The nonaqueous secondary battery 10 includes a positive electrode tab 11, a negative electrode tab 12, and a laminate outer package 16.

  The nonaqueous secondary battery 10 has a substantially rectangular flat shape when viewed from the front, and a positive electrode tab 11 and a negative electrode tab 12 extend from one side thereof. In addition, this structure is an illustration, Comprising: The nonaqueous secondary battery 10 can take arbitrary shapes, and you may extend the positive electrode tab 11 and the negative electrode tab 12 from a different edge | side.

  2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. The nonaqueous secondary battery 10 further includes a plurality of positive electrodes 13, a plurality of negative electrodes 14, a plurality of separators 15, a positive electrode lead 17, and a negative electrode lead 18.

  As shown in FIGS. 2 and 3, the nonaqueous secondary battery 10 has a configuration in which a plurality of positive electrodes 13 and a plurality of negative electrodes 14 are stacked with a separator 15 interposed therebetween. And these are accommodated in the laminate exterior 16 with the electrolyte solution which is not shown in figure. 2 and 3 exemplify a configuration in which two positive electrodes 13 and three negative electrodes 14 are stacked, but the number of stacked layers is arbitrary. Each of the two positive electrodes 13 is connected to the positive electrode tab 11 drawn to the outside of the laminate sheath 16 through a positive electrode lead 17. Similarly, each of the three negative electrodes 14 is connected to the negative electrode tab 12 drawn out of the laminate sheath 16 through the negative electrode lead 18.

  In the present embodiment, a laminated battery is illustrated, but the electrode and the electrolyte may be housed in a can made of a metal such as aluminum.

  A detailed configuration of the positive electrode 13 and the negative electrode 14 will be described with reference to FIGS. 4A to 6. FIG. 4A is an exploded perspective view showing a set of positive electrode 13, negative electrode 14, and separator 15 extracted from nonaqueous secondary battery 10. FIG. 4B is a perspective view after assembly.

  As shown in FIG. 4A, the positive electrode 13 includes a sheet-like positive electrode current collector 131 having a rectangular shape in plan view, and a positive electrode mixture layer 132 formed on both surfaces of the positive electrode current collector 131. The negative electrode 14 is a rectangular sheet-shaped negative electrode current collector 141 in a plan view, and a rectangular negative electrode mixture layer in a plan view formed on both surfaces of the negative electrode current collector 141 in a larger area than the positive electrode mixture layer 132. 142.

  In all of FIG. 4A and drawings to be referred to in the future, the positive electrode mixture layer 132 is formed on both surfaces of the positive electrode current collector 131. However, the positive electrode mixture layer 132 may be formed only on one surface of the positive electrode current collector 131. The same applies to the negative electrode 14, and the negative electrode mixture layer 141 may be formed only on one surface of the negative electrode current collector 141.

  4A shows an example in which a film-like separator is used as the separator 15, the present invention is not limited to this. As will be described later, the separator 15 may be formed by applying a liquid composition composed of filler particles and a binder to at least one selected from the positive electrode 13 and the negative electrode 14.

  As for the negative mix layer 142, the convex part 142a is integrally shape | molded by the peripheral part. As a result, a recess (concave portion) surrounded by the convex portion 142 a is formed in the central portion of the negative electrode mixture layer 142. The positive electrode mixture layer 132 is formed so as to be fitted into the recess with the separator 15 interposed therebetween.

  FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4B. As described above, the convex portion 142 a is integrally formed on the peripheral edge portion of the negative electrode mixture layer 142. And the separator 15 is arrange | positioned so that the surface which has the unevenness | corrugation of this negative mix layer 142 may be followed. The separator 15 is desirably formed in a larger area than the positive electrode 13 and the negative electrode 14 in order to prevent a short circuit between the positive electrode 13 and the negative electrode 14. And the positive mix layer 132 is arrange | positioned so that the unevenness | corrugation formed by this separator 15 may be fitted.

  FIG. 6 is an enlarged view of FIG. Here, h1 represents the thickness of the flat portion of the negative electrode mixture layer 142. h2 represents the thickness of the convex portion 142a of the negative electrode mixture layer 142. g represents the inter-surface distance between the positive electrode mixture layer 132 and the negative electrode mixture layer 142. This value is regulated by the thickness of the separator 15. d represents the difference between the thickness h2 of the convex portion 142a and the inter-surface distance g. That is, d = h2-g. As shown in FIG. 6, this value represents the length of overlap in the thickness direction of the convex portions 142 a of the positive electrode mixture layer 132 and the negative electrode mixture layer 142.

  Until now, the expression that the convex part 142a is formed in the peripheral part of the negative mix layer 142 has been used. However, a recess may be provided at the center of the negative electrode mixture layer 142. As will be described later, the negative electrode mixture layer 142 is formed integrally with the convex portion 142a. Note that since the battery capacity is proportional to the amount of the active material, it is desirable that the volume of the negative electrode mixture layer 142 be large. In that respect, it is desirable that the thickness h1 of the flat portion is approximately the same as the conventional one.

  It is desirable that the value of d = h2−g is large, that is, the value of h2 is large and the value of g is small. Although it is desirable that the value of d is positive, that is, h2> g, a certain effect can be obtained even if it is not.

  As shown in FIG. 6, the convex portion 142a is provided with a forward taper in the stacking direction. This is to increase the strength of the convex portion 142a so that stress is not concentrated on the bent portion. FIG. 6 shows a case where the angle α formed by the outer peripheral wall of the convex portion 142a and the stacking direction is different from the angle β formed by the inner peripheral wall of the convex portion 142a and the stacked direction. However, these may be the same angle.

  It should be noted that the peripheral wall of the positive electrode mixture layer 132 is also provided along the unevenness provided in the negative electrode mixture layer 142 (more precisely, along the separator 15 disposed along the negative electrode mixture layer 142. ), And a taper of the same angle β as that of the inner peripheral wall of the negative electrode mixture layer 142 is provided.

  FIG. 7 is a diagram conceptually showing the exchange of active materials in the nonaqueous secondary battery 10 according to one embodiment of the present invention. As shown in FIG. 7, according to the present embodiment, the positive electrode mixture layer 132 and the negative electrode mixture layer 142 face each other in the stacking direction and also in a direction perpendicular to the stacking direction. Therefore, in addition to the stacking direction, the active material can be exchanged in a direction perpendicular thereto. The reaction rate is proportional to the area of the electrode. Therefore, the load characteristics can be improved by the amount of the area facing each other in the direction perpendicular to the stacking direction.

  Further, according to this configuration, the positive electrode mixture layer 132 and the negative electrode mixture layer 142 are fitted via the separator 15, whereby the positive electrode 13 and the negative electrode 14 can be accurately positioned. Conventionally, such a position restriction requires a jig or device designed exclusively. However, according to this configuration, the position regulation can be accurately performed manually. In addition, it is difficult for deviation to occur after the lamination.

[Method of manufacturing non-aqueous secondary battery]
Hereinafter, a method for manufacturing the nonaqueous secondary battery 10 according to an embodiment of the present invention will be described.

  First, a method for manufacturing the negative electrode 14 will be described with reference to FIGS. 8A to 8C. As the negative electrode mixture layer 142, an active material and a binder are mixed in pure water to prepare a slurry 142 '. As the negative electrode active material, natural graphite, mesophase carbon, amorphous carbon, or the like can be used. As the negative electrode binder, cellulose binders such as carboxymethyl cellulose (CMC) and hydroxypropyl cellulose (HPC), and rubber binders such as styrene butadiene rubber (SBR) and acrylic can be used alone or in combination.

  The adjusted slurry 142 ′ is applied to both surfaces of the negative electrode current collector 141 (FIG. 8A). The slurry 142 ′ may be applied uniformly on both surfaces of the negative electrode current collector 141, or may be applied thickly on the portion where the convex portion 142 a is formed. As the negative electrode current collector 141, a foil of copper, nickel, stainless steel, etc., a plain woven wire mesh, an expanded metal, a lath mesh, or a punching metal can be used. The negative electrode tab 12 and the negative electrode lead 18 may be the same type.

  Unevenness is formed on the slurry 142 ′ by press molding (FIG. 8B). Press molding may be performed by heating or at room temperature. The viscosity of the slurry 142 ′ is adjusted in advance so that the slurry 142 ′ flows without gaps in the unevenness of the mold 90. The viscosity of the slurry 142 'is adjusted by the particle size of the active material and the amount of pure water as a solvent. Moreover, you may add a thickener.

  Drying is performed under pressure and calendering is performed. At this time, the density may be different between the convex portion 142a and other portions.

  Thereafter, the negative electrode current collector 141 is cut into a predetermined size (FIG. 8C). But you may use what was previously cut | disconnected by the predetermined magnitude | size. In addition, an ethylene vinyl acetate copolymer, a polyolefin copolymer, a polyamide copolymer, or the like is applied to the end face of the negative electrode 14 in order to insulate it from the laminate sheath 16.

  The positive electrode 13 is produced by the same procedure. As the positive electrode mixture layer 132, an active material, a conductive additive, and a binder are mixed in an organic solvent to prepare a slurry. As the positive electrode active material, lithium manganate, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, vanadium oxide, molybdenum oxide, or the like can be used. As the conductive additive for the positive electrode, graphite, carbon black, acetylene black or the like can be used, but it is preferable to use carbon black as a main component. As the positive electrode binder, polyimide, polyamideimide, polyamide binder, polytetrafluoroethylene (PTFE) dispersion, PTFE powder, rubber binder, polyvinylidene fluoride (PVDF), or the like can be used, but PVDF is used. Is preferred.

  The slurry thus adjusted is applied to both surfaces of the positive electrode current collector 131. As the positive electrode current collector 131, a foil such as aluminum or titanium, a plain woven wire net, an expanded metal, a lath net, or a punching metal can be used. The positive electrode tab 11 and the positive electrode lead 17 may be the same type.

  Then, irregularities are formed by the positive electrode mold formed so as to be fitted to the negative electrode mold 90 via a predetermined clearance. That is, the surface shape of the positive electrode mixture layer 132 is molded so as to fit the negative electrode mixture layer 142 with a predetermined thickness (for example, a thickness of 15 minutes for the separator).

  In addition, when the convex part 142a is formed only in the peripheral part of the negative mix layer 142 like this embodiment, it is not necessary to form an unevenness | corrugation on the surface of the positive mix layer 132. FIG. Only the regulation of the dimensions of the positive electrode mixture layer 132 and the processing of the end portion need be performed, and the processing becomes relatively easy.

  As the separator 15, a microporous film or a nonwoven fabric such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polyphenyl sulfide (PPS) can be used. .

  The separator 15 can also be formed by applying a liquid composition composed of filler particles and a binder resin to at least one selected from the positive electrode 13 and the negative electrode 14. In this case, compared with the case where the above-mentioned microporous film and a nonwoven fabric are used, the thickness of the separator 15 can be made thin. Further, it is preferable because the followability of the positive electrode mixture layer 132 and the negative electrode mixture layer 142 to the unevenness is improved.

  The filler particles have heat resistance and electrical insulation, are stable with respect to the solvent used in the production of the electrolytic solution and the separator 15, and are not easily oxidized or reduced in the battery operating voltage range. Chemically stable fine particles are used. As a specific example, alumina, silica, boehmite, or the like can be used. Further, in order to ensure the shape stability and flexibility of the separator 15, a fibrous material may be mixed.

  The filler particles and the binder are dispersed or dissolved in a solvent to obtain a liquid composition. The liquid composition preferably has a solid content of 10 to 40% by mass. And this liquid composition is apply | coated to at least one chosen from the positive electrode 13 and the negative electrode 14, and is dried at predetermined temperature. Thereby, a porous substrate made of a large number of filler particles is formed integrally with the positive electrode or the negative electrode as the separator 15.

  In the liquid composition, resin fine particles (shutdown resin) having a melting point of 80 to 140 ° C. may be mixed. The shutdown resin melts at the time of abnormal heat generation, closes the pores of the separator 15, and suppresses the progress of the electrochemical reaction. As specific examples, polyethylene, polyolefin wax, ethylene-vinyl acetate copolymer, or the like can be used.

  The liquid composition may be applied to at least one surface selected from the above-mentioned positive electrode mixture layer slurry and negative electrode mixture layer slurry 142 ′, and the electrode molding and the separator 15 formation may be performed simultaneously. good.

  A predetermined number of the positive electrode 13 and the negative electrode 14 thus manufactured are stacked via a separator 15. Alternatively, a predetermined number of positive electrodes 13 and negative electrodes 14, at least one of which is integrated with the separator 15, are stacked. Each of the positive electrodes 13 is connected to the positive electrode tab 11 via the positive electrode lead 17. Similarly, each of the negative electrodes 14 is connected to the negative electrode tab 11 via the negative electrode lead 18. The positive electrode 13 and the positive electrode lead 17, the positive electrode lead 17 and the positive electrode tab 11, the negative electrode 14 and the negative electrode lead 18, and the negative electrode lead 18 and the negative electrode tab 12 are connected by resistance welding, ultrasonic welding, laser welding, caulking, or conductivity. An adhesive or the like can be used.

  The electrode laminate obtained as described above is accommodated in a laminate sheath 16 and an electrolytic solution is injected. Thereafter, the laminate exterior is sealed with a heat-sealing resin.

As the laminate exterior 16, an aluminum laminate sheet or the like can be used. As the electrolytic solution, a solution in which a lithium salt is dissolved in an organic solvent is used. Organic solvents include vinylene carbonate (VC), propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), and γ From butyrolactone or the like, one kind or a mixture of two or more kinds can be used. As the lithium salt, LiPF ₆ , LiBF ₄ , LiN (CF ₃ SO ₂ ) _2, or the like can be used.

  The manufacturing method of the non-aqueous secondary battery 10 according to the present embodiment has been described above. As is clear from the above, in the present embodiment, the case where the nonaqueous secondary battery 10 is a laminate type lithium ion secondary battery is illustrated. The present invention is particularly useful when the non-aqueous secondary battery 10 is this type of battery. However, this does not limit the application of the present invention, and can be applied to various nonaqueous secondary batteries within the scope of the invention.

[Other Embodiments]
Next, a modification of the embodiment of the present invention will be described with reference to FIGS. 9A to 10F.

  FIG. 9A is an exploded perspective view showing a set of the positive electrode 13, the negative electrode 14, and the separator 15 extracted from the nonaqueous secondary battery according to the first modification of the present invention. FIG. 9B is a cross-sectional view showing a set of the positive electrode 13, the negative electrode 14, and the separator 15 extracted from the nonaqueous secondary battery according to the present modification. Also in this modification, the positive electrode 13 includes a positive electrode current collector 131 and a positive electrode mixture layer 132. Similarly, the negative electrode 14 includes a negative electrode current collector 141 and a negative electrode mixture layer 142.

  In the above-described embodiment, the convex portion 142 a is formed on the peripheral edge portion of the negative electrode mixture layer 142. In the present modification, a convex portion 142 b is formed at the central portion of the negative electrode mixture layer 142. And the separator 15 is arrange | positioned so that the unevenness | corrugation formed by the negative mix layer 142 may be followed. Further, a convex portion 132 b is formed on the peripheral edge portion of the positive electrode mixture layer 132 so as to be fitted to the unevenness formed by the separator 15.

  Also in this modification, the area where the positive electrode 13 and the negative electrode 14 face each other can be increased. Therefore, load characteristics can be improved.

  FIG. 10A is an exploded perspective view showing a set of the positive electrode 13, the negative electrode 14, and the separator 15 extracted from the nonaqueous secondary battery according to the second modification of the present invention. In this modification, in addition to the convex portion 142 c ′ formed on the peripheral edge portion of the negative electrode mixture layer 142, a plurality of convex portions 142 c are also formed inside the peripheral edge portion. A plurality of convex portions 132 c are also formed on the surface of the positive electrode mixture layer 132 so as to be fitted via the separator 15 corresponding to the unevenness formed by the negative electrode mixture layer 142.

  In addition, what kind of shape these convex part 132c and convex part 142c have in planar view is arbitrary. For example, the convex portions formed on the line may be arranged in one direction, or the circular convex portions may be arranged concentrically.

  According to this modification, the area where the positive electrode 13 and the negative electrode 14 face each other is further increased. Therefore, the load characteristics can be further improved.

  FIG. 10B is a cross-sectional view showing a set of the positive electrode 13, the negative electrode 14, and the separator 15 extracted from the nonaqueous secondary battery according to the third modification of the present invention. In this modified example, as in the second modified example, convex portions 142d 'are formed on the peripheral edge portion of the negative electrode mixture layer 142, and a plurality of convex portions 142d are formed on the inner side of the peripheral edge portion. Further, the positive electrode mixture layer 132 is formed so as to fit through the separator 15 in correspondence with the unevenness formed by the negative electrode mixture layer 142. In this modified example, unlike the second modified example, the positive electrode mixture layer 132 is composed of a plurality of convex portions 132d having a rectangular cross-sectional view and separated from each other in a cross-sectional view. That is, a plurality of convex portions 132 d are formed on the surface of the positive electrode current collector 131. As in the second modification, the shape of the convex portions 132d, 142d, 142d 'in a plan view is arbitrary. The protrusions 132d are separated from each other in a sectional view, but may be continuous in a plan view.

  FIG. 10C is a cross-sectional view showing a set of the positive electrode 13, the negative electrode 14, and the separator 15 extracted from the nonaqueous secondary battery according to the fourth modification of the present invention. This modified example and the second modified example differ in the cross-sectional shape of the convex portions formed in the negative electrode mixture layer 142 and the positive electrode mixture layer 132. That is, in the second modified example, a convex portion 142 c having a substantially rectangular shape in cross section is formed on the negative electrode mixture layer 142. In the present modification, a convex portion 142 e having a triangular shape in cross section is formed on the negative electrode mixture layer 142. Correspondingly, a convex portion 132e having a triangular shape in cross section is formed on the surface of the positive electrode mixture layer 132 so as to be fitted via the separator 15.

  FIG. 10D is a cross-sectional view showing a set of the positive electrode 13, the negative electrode 14, and the separator 15 extracted from the nonaqueous secondary battery according to the fifth modification of the present invention. In the present modification, the positive electrode mixture layer 132 is composed of a plurality of triangular protrusions 132f that are spaced apart from each other in sectional view. That is, a plurality of convex portions 132 f are formed on the surface of the positive electrode current collector 131. The negative electrode mixture layer 142 is composed of a plurality of triangular convex portions 142f that are separated from each other when viewed in cross section. That is, a plurality of convex portions 142 f are formed on the surface of the negative electrode current collector 141. The positive electrode mixture layer 132 and the negative electrode mixture layer 142 are formed so as to be fitted to each other via the separator 15.

  FIG. 10E is a cross-sectional view showing a set of the positive electrode 13, the negative electrode 14, and the separator 15 extracted from the nonaqueous secondary battery according to the sixth modification of the present invention. In the present modification, a convex portion 132 g having a circular arc shape in cross section is formed on the surface of the positive electrode mixture layer 132. Correspondingly, arc-shaped concave portions 142g and 142g 'are formed on the surface of the negative electrode mixture layer 142 so as to be fitted via the separator 15.

  FIG. 10F is a cross-sectional view showing a set of the positive electrode 13, the negative electrode 14, and the separator 15 extracted from the nonaqueous secondary battery according to the seventh modification of the present invention. In the present modification, convex portions 132 h having a circular arc shape in cross section are formed on the surface of the positive electrode mixture layer 132 at intervals. Correspondingly, arc-shaped concave portions 142 h and 142 h ′ are formed on the surface of the negative electrode mixture layer 142 so as to be fitted via the separator 15.

  Also by these modified examples, the area where the positive electrode 13 and the negative electrode 14 face each other can be increased. Therefore, load characteristics can be improved.

  As mentioned above, although embodiment about this invention was described, this invention is not limited only to the above-mentioned embodiment and each modification, A various change is possible within the scope of the invention.

  The present invention is applicable to non-aqueous secondary batteries.

DESCRIPTION OF SYMBOLS 10 Nonaqueous secondary battery, 11 Positive electrode tab, 12 Negative electrode tab, 13 Positive electrode, 131, Positive electrode collector, 132 Positive electrode mixture layer, 14 Negative electrode, 141 Negative electrode collector, 142 Negative electrode mixture layer, 142a Convex part, 15 Separator, 16 laminate exterior, 17 positive lead, 18 negative lead

Claims (4)

A negative electrode having irregularities formed on a flat sheet-shaped surface;
A separator disposed along the surface having the uneven portion of the negative electrode;
A sheet-like positive electrode having a surface area smaller than the negative electrode and having a surface that fits into the irregularities formed by the separator;
The non-aqueous secondary battery, wherein the negative electrode and the positive electrode are opposed to each other so that charging / discharging is possible in the stacking direction, and are also facing so as to be able to charge / discharge also in a direction perpendicular to the stacking direction. The non-aqueous secondary battery according to claim 1,
The separator is a non-aqueous secondary battery integrated with at least one selected from the positive electrode and the negative electrode. The non-aqueous secondary battery according to claim 1 or 2,
A non-aqueous secondary battery in which a convex portion is formed on a peripheral portion of the negative electrode surface. The nonaqueous secondary battery according to any one of claims 1 to 3,
The non-aqueous secondary battery in which the convex portion of the concave and convex portion has a forward tapered shape.

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