Secondary battery and manufacturing method of secondary battery

Abstract

To provide a secondary battery in which the generation of a liquid junction is suppressed.SOLUTION: A secondary battery comprises a wound type electrode body in which an electrode lamination body extending in first and second directions is wound in the second direction as an axis. The electrode lamination body includes a unit (A), a unit (B), and an insulation body. The unit (A) is formed by laminating a separator, a negative electrode active material layer, a collector (A1), the negative electrode active material layer, the separator, a positive electrode active material layer, a collector (A2), and the positive electrode active material layer in this order along a third direction. The unit (B) is formed by laminating the separator, the positive electrode active material layer, a collector (B1), the positive electrode active material layer, the separator, the negative electrode active material layer, a collector (B2), and the negative electrode active material layer in this order along the third direction. The collector (A1) and the collector (B1) are an integral collector, or the collector (A2) and the collector (B2) are an integral collector.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a secondary battery and a method for manufacturing the secondary battery.

Background Art

[0002] A lithium secondary battery using a non-aqueous electrolyte (hereinafter also referred to as a "secondary battery") is used for in-vehicle applications, information and communication technologies (e.g., personal computers, smartphones, etc.), and power storage.

[0003] In order to increase the output and capacity of secondary batteries, the development of bipolar batteries has been promoted. Patent Document 1 discloses a bipolar lithium-ion secondary battery 900 (hereinafter also referred to as a "laminated bipolar battery 900"). As shown in FIG. 17, the laminated bipolar battery 900 includes a power generation element 910 and an exterior body 920. The power generation element 910 is sealed inside the exterior body 920.

[0004] As shown in FIG. 18, the power generation element 910 has a plurality of bipolar electrodes 911 and a plurality of separators 912. The bipolar electrode 911 has a current collector 9110, a specific positive electrode layer 9111, and a specific negative electrode layer 9112. The positive electrode layer 9111 is electrically connected to one surface of the current collector 9110. The negative electrode layer 9112 is electrically connected to the other surface of the current collector 9110. Each of the plurality of bipolar electrodes 911 is laminated via a separator 912. The positive electrode layer 9111, the separator 912, and the negative electrode layer 9112 constitute one single cell layer 913.

[0005] A resin seal portion 930 is disposed on the outer peripheral portion of the single cell layer 913. In other words, it seals the side peripheral surface of the rectangular parallelepiped-shaped power generation element 910. The seal portion 930 prevents the occurrence of a liquid junction due to leakage of the electrolyte from the separator 912. The seal portion 930 prevents the adjacent current collectors 9110 from contacting each other. The seal portion 930 prevents the occurrence of a short circuit due to a slight unevenness at the end of the single cell layer 913.

[0006] On the outermost positive electrode current collector 9110a located on the outermost layer of the power generation element 910, a positive electrode current collecting plate 940 is electrically connected. On the outermost negative electrode current collector 9110b located on the outermost layer of the power generation element 910, a negative electrode current collecting plate 950 is electrically connected.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] In the laminated bipolar battery 900, the stacking direction of the plurality of bipolar electrodes 911 and the direction from the central portion to the periphery of the power generation element 910 when viewing the power generation element 910 from the stacking direction of the plurality of bipolar electrodes 911 can become short - circuit paths. The total area of the walls of the seal portions 930 that isolate the electrolytes of each of the plurality of single - cell layers 913 (hereinafter also referred to as "partition area") is relatively large. The larger the partition area, the higher the possibility that the electrolyte leaks from the seal portion 930. When the electrolyte leaks from the seal portion 930, there is a possibility of liquid junction occurring between the plurality of single - cell layers 913. The occurrence of liquid junction can be a factor that degrades the battery performance of the laminated bipolar battery 900. Therefore, a secondary battery with suppressed occurrence of liquid junction is required.

[0009] This disclosure is in view of the above circumstances. The problem to be solved by one embodiment of this disclosure is to provide a secondary battery with suppressed occurrence of liquid junction. The problem to be solved by another embodiment of this disclosure is to provide a method for manufacturing a secondary battery that can manufacture a secondary battery with suppressed occurrence of liquid junction.

Means for Solving the Problems

[0010] Means for solving the above problems include the following embodiments.

[0011] <1>The secondary battery according to the first aspect of the present disclosure is a wound electrode body, an electrolytic solution, an exterior body that houses the wound electrode body and the electrolytic solution, and is provided with the wound electrode body is formed by winding a rectangular electrode laminate that extends in a first direction and a second direction orthogonal to the first direction about the second direction as an axis, the electrode laminate has at least one unit (A), at least one unit (B) that is electrically connected in series with the unit (A) and is spaced apart from the unit (A) in the second direction, at least one insulator filled in a gap between the adjacent unit (A) and the unit (B), and has the unit (A) includes a first laminate formed by laminating a separator, a negative electrode active material layer, a current collector (A1), the negative electrode active material layer, the separator, a positive electrode active material layer, a current collector (A2), and the positive electrode active material layer in this order along a third direction orthogonal to the first direction and the second direction, the unit (B) includes a second laminate formed by laminating the separator, the positive electrode active material layer, a current collector (B1), the positive electrode active material layer, the separator, the negative electrode active material layer, a current collector (B2), and the negative electrode active material layer in this order along the third direction, the current collector (A1) and the current collector (B1) are an integral current collector, or the current collector (A2) and the current collector (B2) are an integral current collector, the insulator partitions a space between the wound electrode body and the exterior body by contact with the exterior body, and is a secondary battery.

[0012] "Insulator" refers to a material having a function of not allowing electrons to flow and a function of not allowing ions to flow. Specifically, the electronic conductivity of the insulator is 1.0×10 -16 Scm -1is as follows. The ionic conductivity of the insulator is 1.0×10 -16 Scm -1 or less.

[0013] In the first aspect, at least two unit cells are configured in the second direction of the wound electrode body. The electrolytes of each of the at least two unit cells are separated by an insulator. The "unit cell" refers to a laminate in which a negative electrode active material layer, a separator, and a positive electrode active material layer are laminated in this order. That is, in the first aspect, only the second direction can be a liquid junction path. Therefore, the total area of the walls of the insulator that separates the electrolytes of each of the plurality of unit cells is smaller than the partition area of the laminated bipolar battery 900. As a result, in the secondary battery of the first aspect, the generation of liquid junction is suppressed.

[0014] <2>The secondary battery according to the second aspect of the present disclosure is the thickness of the unit (A) and the thickness of the unit (B) are the same, the thickness of the first contact portion of the current collector with the negative electrode active material layer and the thickness of the second contact portion of the current collector with the positive electrode active material layer are different, at least one of the first contact portion and the second contact portion is the first configuration or the second configuration, the first configuration consists of one metal layer, the second configuration consists of at least two metal layers, which is the secondary battery according to <1>. That is.

[0015] Generally, the thickness of the negative electrode active material layer is not the same as the thickness of the positive electrode active material layer, and the thickness of the current collector is the same along the longitudinal direction of the current collector. Therefore, the thicknesses of the parts constituting the unit (A) of the electrode laminate and the thicknesses of the parts constituting the unit (B) of the electrode laminate often differ. In this case, when the secondary battery is sandwiched and constrained between a pair of flat plates, the pressure applied to the parts constituting the unit (A) of the electrode laminate and the pressure applied to the parts constituting the unit (B) of the electrode laminate are different. That is, there is a risk of shear stress being generated in the current collector and separator of the secondary battery. As a result, the current collector and separator may break or plastically deform. Consequently, the battery performance of the secondary battery may deteriorate. In the second aspect, the thickness of the unit (A) and the thickness of the unit (B) are the same, and the thickness of the first contact portion of the current collector with the negative electrode active material layer and the thickness of the second contact portion of the current collector with the positive electrode active material layer are different. Therefore, when the secondary battery is sandwiched and constrained between a pair of flat plates, the pressure applied to the parts constituting the unit (A) of the electrode laminate and the pressure applied to the parts constituting the unit (B) of the electrode laminate become the same. That is, shear stress is less likely to be generated in the current collector and separator of the secondary battery. As a result, the current collector and separator are less likely to break or plastically deform. Consequently, in the secondary battery of the second aspect, the battery performance is less likely to deteriorate.

[0016] <3>The secondary battery according to the third aspect of the present disclosure is wherein the at least one unit (A) is a plurality of the units (A), the at least one unit (B) is a plurality of the units (B), the at least one insulator is a plurality of insulators, and the unit (A) and the unit (B) are alternately arranged along the second direction, which is the secondary battery according to <1> or <2>.

[0017] As a result, the secondary battery of the third aspect has three or more single battery layers. Each of the three or more single battery layers is connected in series. As a result, the secondary battery of the third aspect can have a higher output voltage than a configuration in which each of two single battery layers is connected in series.

[0018] <4>The manufacturing method of the secondary battery of the fourth aspect of the present disclosure is <1>~<3> any one of the manufacturing methods of the secondary battery according to any one of the above, preparing a first sheet having the current collector, the positive electrode active material layer laminated on a part of both main surfaces of the current collector, the negative electrode active material layer spaced apart from the positive electrode active material layer in the second direction and laminated on a part of both main surfaces of the current collector; forming the insulator in a gap between the adjacent positive electrode active material layer and the negative electrode active material layer on both main surfaces of the first sheet to produce a second sheet; laminating the separator on each of the positive electrode active material layer and the negative electrode active material layer on both main surfaces of the second sheet, and forming the insulator in a gap between adjacent separators to produce a third sheet; separating the exposed portion of the current collector located between the adjacent positive electrode active material layer and the negative electrode active material layer of the first sheet from the first sheet, and forming the insulator in the gap between the separated current collectors and the gap between the adjacent positive electrode active material layer and the negative electrode active material layer to produce a fourth sheet; laminating the fourth sheet on the third sheet to produce the electrode laminate; including, a manufacturing method of a secondary battery.

[0019] As a result, the manufacturing method of the secondary battery of the fourth aspect can manufacture a secondary battery in which the occurrence of liquid leakage is suppressed.

[0020] <5>The manufacturing method of the secondary battery of the fifth aspect of the present disclosure is <1>~<3> any one of the manufacturing methods of the secondary battery according to any one of the above, Preparing a first sheet having the current collector, the positive electrode active material layer laminated on a part of both main surfaces of the current collector, the negative electrode active material layer spaced apart from the positive electrode active material layer in the second direction and laminated on a part of both main surfaces of the current collector; Forming the insulator in a gap between the adjacent positive electrode active material layer and the negative electrode active material layer on both main surfaces of the first sheet to produce a second sheet; Laminating the separator on each of the positive electrode active material layer and the negative electrode active material layer on one main surface of the second sheet, and forming the insulator in a gap between the adjacent separators to produce a third sheet; Cutting both end portions of the third sheet in the second direction along the third direction to separate the third sheet into a third sheet central portion piece including the insulator and a pair of third sheet end pieces not including the insulator; Forming the insulator in a gap between the current collectors of the pair of third sheet end pieces and in a gap between the adjacent positive electrode active material layer and the negative electrode active material layer to produce a fourth sheet; Laminating the fourth sheet on the third sheet central portion piece to produce the electrode laminate; A method for manufacturing a secondary battery, including the above steps.

[0021] Accordingly, the method for manufacturing a secondary battery according to the fifth aspect can manufacture a secondary battery in which the occurrence of liquid leakage is suppressed.

[0022] <6>The method for manufacturing a secondary battery according to the sixth aspect of the present disclosure Further includes winding the electrode laminate around the second direction as an axis to produce the wound electrode body, and is the method for manufacturing a secondary battery according to <4> or <5>.

[0023] Accordingly, the method for manufacturing a secondary battery according to the sixth aspect can manufacture a secondary battery in which the occurrence of liquid leakage is suppressed.

[0024] <7>The method for manufacturing a secondary battery according to the seventh aspect of the present disclosure The thickness of the unit (A) is the same as the thickness of the unit (B), The thickness of the first contact portion of the current collector with the negative electrode active material layer is different from the thickness of the second contact portion of the current collector with the positive electrode active material layer. Preparing a current collector precursor; The method for manufacturing a secondary battery according to any one of <4> to <6>, further comprising subjecting at least one of a stretching process, an etching process, an electrolytic plating process, and an electroless plating process to the first contact portion or the second contact portion of the current collector precursor to produce the current collector.

[0025] The "current collector precursor" refers to the material of the current collector.

[0026] Thereby, when the positive electrode active material layer and the negative electrode active material layer are densified by pressing, the thickness of the first contact portion of the current collector and the total thickness of the negative electrode active material layer formed on the first contact portions on both sides of the current collector, and the thickness of the second contact portion of the current collector and the total thickness of the positive electrode active material layer formed on the second contact portions on both sides of the current collector can be the same. Therefore, even when the positive electrode active material layer and the negative electrode active material layer are pressed, shear stress is less likely to occur in the current collector. In addition, also when the electrode laminate is sandwiched and restrained by a pair of gripping tools in which the portion in contact with the electrode laminate is planar during the manufacturing process of the secondary battery, shear stress is less likely to occur in the current collector and the separator of the electrode laminate. As a result, the manufacturing method of the seventh aspect can manufacture a secondary battery without breaking the current collector and the separator and without causing plastic deformation in the current collector and the separator.

[0027] <8>The method for manufacturing a secondary battery according to the eighth aspect of the present disclosure is The thickness of the unit (A) is the same as the thickness of the unit (B), The thickness of the first contact portion of the current collector with the negative electrode active material layer is different from the thickness of the second contact portion of the current collector with the positive electrode active material layer. The method for manufacturing a secondary battery according to any one of <4> to <6>, further comprising producing the current collector composed of at least two metal layers.

[0028] As a result, when the positive electrode active material layer and the negative electrode active material layer are consolidated by pressing, the total thickness of the thickness of the first contact portion of the current collector and the thickness of the negative electrode active material layer formed on the first contact portions on both surfaces of the current collector can be the same as the total thickness of the thickness of the second contact portion of the current collector and the thickness of the positive electrode active material layer formed on the second contact portions on both surfaces of the current collector. Therefore, even when the positive electrode active material layer and the negative electrode active material layer are pressed, shear stress is less likely to occur in the current collector. In addition, also when the electrode laminate is clamped and constrained by a pair of gripping tools whose portions in contact with the electrode laminate are planar in the manufacturing process of the secondary battery, shear stress is less likely to occur in the current collector and the separator of the electrode laminate. As a result, the manufacturing method of the eighth aspect can manufacture a secondary battery without breaking the current collector and the separator and without causing plastic deformation in the current collector and the separator.

[0029] <9>The manufacturing method of the secondary battery according to the ninth aspect of the present disclosure is wherein the at least one unit (A) is a plurality of the units (A), the at least one unit (B) is a plurality of the units (B), the at least one insulator is a plurality of insulators, and the unit (A) and the unit (B) are alternately arranged along the second direction, which is the manufacturing method of the secondary battery according to any one of <4> to <8>.

[0030] As a result, the manufacturing method of the secondary battery according to the ninth aspect of the present disclosure can manufacture a secondary battery having three or more single battery layers. Each of the three or more single battery layers is connected in series. As a result, the manufacturing method of the secondary battery according to the ninth aspect can manufacture a secondary battery capable of increasing the output voltage compared to a configuration in which each of the two single battery layers is connected in series.

Advantages of the Invention

[0031] According to the present disclosure, a secondary battery with suppressed generation of liquid leakage is provided. According to the present disclosure, a method for manufacturing a secondary battery capable of manufacturing a secondary battery with suppressed generation of liquid leakage is provided.

Brief Description of the Drawings

[0032]

Figure 1

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Figure 12

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Figure 17

Figure 18

MODE FOR CARRYING OUT THE INVENTION

[0033] In the present disclosure, the numerical range indicated using "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

[0034] Hereinafter, embodiments of the secondary battery and the method for manufacturing the secondary battery of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description thereof will not be repeated.

[0035] (1) First Embodiment (1.1) Secondary Battery As shown in FIG. 1, the secondary battery 1A according to the first embodiment includes a wound electrode body 10A, an electrolytic solution (not shown), a cylindrical exterior body 20A, a shaft 30 (see FIG. 2), a current collector tab 40A, and a current collector tab 40B. The wound electrode body 10A is formed by winding a rectangular electrode laminate 10a around the shaft 30 (see FIG. 2). The wound electrode body 10A is cylindrical. The current collector tabs 40A and 40B electrically connect the wound electrode body 10A and the exterior body 20A. The exterior body 20A houses the wound electrode body 10A, the electrolytic solution, the shaft 30, the current collector tab 40A, and the current collector tab 40B.

[0036] In the first embodiment, the longitudinal direction of the rectangular electrode laminate 10a is defined as the X-axis direction. The short side direction of the rectangular electrode laminate 10a is defined as the Y-axis direction. The thickness direction of the rectangular electrode laminate 10a is defined as the Z-axis direction. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis direction is an example of the first direction. The Y-axis direction is an example of the second direction. The Z-axis direction is an example of the third direction. Note that these directions do not limit the orientation during use of the secondary battery of the present disclosure.

[0037] The applications of the secondary battery 1A include, for example, in-vehicle use, information and communication technology (e.g., personal computers, smartphones, etc.), power storage, etc. A plurality of secondary batteries 1A are preferably used in the form of a battery module.

[0038] (1.1.1) Wound electrode body As shown in FIGS. 2 and 3, the wound electrode body 10A is formed by winding the rectangular electrode laminate 10a twice around the Y-axis direction.

[0039] The wound electrode body 10A may be housed in the exterior body 20A in a state of being housed in an insulating packaging bag. The material of the insulating packaging bag is resin (e.g., polyethylene, polypropylene, etc.).

[0040] The size and number of windings of the wound electrode body 10A are appropriately selected according to the application of the secondary battery 1A and the like.

[0041] The electrode laminate 10a is a sheet-like material. Both main surfaces of the electrode laminate 10a are planar. The thickness L1 (the length L1 in the Z-axis direction) of each part of the electrode laminate 10a is constant.

[0042] In the first embodiment, as shown in FIGS. 3 and 4, the electrode laminate 10a has one unit (A) 11, one unit (B) 12, and one insulator 13. The unit (B) 12 is electrically connected in series with the unit (A) 11. The unit (B) 12 is spaced apart from the unit (A) 11 in the Y-axis direction. The insulator 13 is filled in the gap between the adjacent unit (A) 12A and the unit (B) 12B.

[0043] (1.1.1.1) Unit (A) and Unit (B) Unit (A) 11 constitutes one unit cell in the secondary battery 1A. Unit (B) 12 constitutes one unit cell in the secondary battery 1A. The "unit cell" refers to a laminate in which a negative electrode active material layer, a separator, and a positive electrode active material layer are laminated in this order. The unit cell of Unit (A) 11 and the unit cell of Unit (B) 12 are different.

[0044] In the first embodiment, as shown in FIG. 4, Unit (A) 11 is composed of a first laminate 110. The first laminate 110 is formed by laminating a separator 101, a negative electrode active material layer 102, a current collector (A1) 111, a negative electrode active material layer 102, a separator 101, a positive electrode active material layer 103, a current collector (A2) 112, and a positive electrode active material layer 103 in this order along the positive Z-axis direction.

[0045] In the first embodiment, Unit (B) 12 is composed of a second laminate 120. The second laminate 120 is formed by laminating a separator 101, a positive electrode active material layer 103, a current collector (B1) 121, a positive electrode active material layer 103, a separator 101, a negative electrode active material layer 102, a current collector (B2) 122, and a negative electrode active material layer 102 in this order along the positive Z-axis direction.

[0046] In the first embodiment, the current collector (A1) 111 and the current collector (B1) 121 are an integral current collector 100A. The current collector (A2) 112 and the current collector (B2) 122 are not an integral current collector.

[0047] As shown in FIG. 5, the current collector 100A has a first contact portion R111 that contacts the negative electrode active material layer 102 and a second contact portion R121 that contacts the positive electrode active material layer 103. The thickness L2 (the length L2 in the Z-axis direction) of the first contact portion R111 is different from the thickness L3 (the length L3 in the Z-axis direction) of the second contact portion R121. In the first embodiment, the thickness L2 is thinner than the thickness L3. The total thickness L4 of the thickness L2 of the current collector 100A and the thickness of the negative electrode active material layer 102 formed on both surfaces of the current collector 100A is the same as the total thickness L4 of the thickness L3 of the current collector 100A and the thickness of the positive electrode active material layer 103 formed on both surfaces of the current collector 100A. The thickness L1 (the length L1 in the Z-axis direction) of the unit (A) 11 is the same as the thickness L1 (the length L1 in the Z-axis direction) of the unit (B) 12.

[0048] The current collector 100A electrically connects the unit (A) 11 and the unit (B) 12 in series. The current collector 100A supplies current to the positive electrode active material layer 103 and the negative electrode active material layer 102 during discharge or charging of the secondary battery 1A. In the first embodiment, the current collector 100A is composed of one metal layer. The current collector 100A is a metal foil. Examples of the metal foil include aluminum foil, copper foil, nickel foil, titanium foil, stainless steel foil, and the like. A coating layer may be formed on the surface of the current collector 100A. The coating layer may be formed by a known method (for example, plating treatment, spray coating, etc.). The thickness of the current collector 100A may be 1 μm to 100 μm.

[0049] The current collectors (A2) 112 and (B2) 122 (hereinafter also referred to as "current collectors 112, 122") supply current to the positive electrode active material layer 103 and the negative electrode active material layer 102 during discharge or charging of the secondary battery 1A. Examples of the material of the current collectors 112, 122 include metal foils, conductive resin materials, or conductive inorganic materials. Examples of the metal foil include aluminum foil, copper foil, nickel foil, titanium foil, stainless steel foil, and the like. Examples of the conductive resin material include resin obtained by adding a conductive filler to a conductive polymer material or a non-conductive polymer material as necessary. A coating layer may be formed on the surface of the current collectors 112, 122. The coating layer may be formed by a known method (for example, plating treatment, spray coating, etc.). The thickness of the current collectors 112, 122 may be 1 μm to 100 μm.

[0050] The separator 101 maintains the distance between the positive electrode active material layer 103 and the negative electrode active material layer 102 to prevent the occurrence of a short circuit due to contact, and allows charge carriers (for example, lithium ions, etc.) to pass through. Examples of the separator 101 include a porous resin sheet or a non-woven fabric. Examples of the material of the porous resin sheet include polyolefin (polypropylene, polyethylene, etc.) or polyester. Examples of the material of the non-woven fabric include polypropylene, polyethylene terephthalate, or methyl cellulose. The separator 101 may have a known configuration.

[0051] The negative electrode active material layer 102 contains a negative electrode layer active material (for example, carbon, a compound capable of alloying with lithium, etc.) that can occlude and release charge carriers. Examples of the carbon include natural graphite, artificial graphite, hard carbon (carbon with low graphitization property), or soft carbon (carbon with high graphitization property). Examples of the artificial graphite include highly oriented graphite, mesocarbon microbeads, and the like. Examples of the element capable of alloying with lithium include silicon or tin. The thickness (length in the Z-axis direction) of the negative electrode active material layer 102 may be 2 μm to 500 μm.

[0052] The positive electrode active material layer 103 contains a positive electrode layer active material (for example, a lithium composite metal oxide having a layered rock salt structure, a metal oxide having a spinel structure, a polyanion-based compound, etc.) that can occlude and release charge carriers. The thickness (length in the Z-axis direction) of the positive electrode active material layer 103 may be 2 μm to 500 μm. In the first embodiment, the thickness of the positive electrode active material layer 103 is thinner than the thickness of the negative electrode active material layer 102.

[0053] Each of the positive electrode active material layer 103 and the negative electrode active material layer 102 may further contain a conductive assistant for enhancing electron conductivity, a binder, an electrolyte support salt (lithium salt) for enhancing ion conductivity, a polymer electrolyte, an additive (for example, trifluoropropylene carbonate, a filler as a reinforcing material, etc.) as needed. Examples of the conductive assistant include carbon nanofibers, acetylene black, carbon black, or graphite. Examples of the binder include fluorine-containing resins (polyvinylidene fluoride, polytetrafluoroethylene, fluororubber, etc.), thermoplastic resins (for example, polypropylene, polyethylene, etc.), imide-based resins (for example, polyimide, polyamideimide, etc.), alkoxysilyl group-containing resins, acrylic resins (for example, acrylic acid or methacrylic acid, etc.), styrene-butadiene rubber (SBR), carboxymethyl cellulose, alginates (for example, sodium alginate or ammonium alginate, etc.), water-soluble cellulose ester cross-linked bodies, starch-acrylic acid graft polymers, etc. These binders may be used alone or in combination of two or more.

[0054] (1.1.1.2) Insulator The insulator 13 partitions the space between the wound electrode body 10A and the exterior body 20A into a first space R20A and a second space R20B as shown in FIG. 1 by contact with the exterior body 20A. In other words, the insulator 13 isolates the electrolyte in the first space R20A from the electrolyte in the second space R20B. That is, the insulator 13 prevents a liquid junction.

[0055] The insulator 13 is solid. In other words, the insulator 13 does not have a plurality of pores inside it.

[0056] The material of the insulator 13 is not particularly limited as long as it can endow the insulator 13 with the functions of not allowing electrons to flow and not allowing ions to flow. From the perspective of the moldability of the insulator 13, the insulator 13 may be a resin. Examples of the material of the insulator 13 include acrylic resin, urethane resin, epoxy resin, polyethylene resin, polypropylene resin, polyimide resin, rubber (ethylene-propylene-diene rubber: EPDM), etc.

[0057] (1.1.2) Electrolyte The electrolyte is not particularly limited. As the electrolyte, a liquid electrolyte, a gel polymer electrolyte, or an ionic liquid electrolyte may be used. The electrolyte may be a known electrolyte.

[0058] The liquid electrolyte functions as a carrier of lithium ions. The liquid electrolyte may contain an organic solvent and a lithium salt dissolved in the organic solvent, and may further contain an additive in addition to the organic solvent and the lithium salt. Examples of the organic solvent include ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate, etc. Only one kind of organic solvent may be used alone, or two or more kinds may be used in combination. Examples of the lithium salt include Li(C2F5SO2)2N, LiPF6, LiBF4, LiClO4, LiAsF6, LiCF3SO3, etc. Only one kind of lithium salt may be used alone, or two or more kinds may be used in combination. Examples of the additive include vinylene carbonate, methyl vinylene carbonate, dimethyl vinylene carbonate, phenyl vinylene carbonate, diphenyl vinylene carbonate, etc. Only one kind of these additives may be used alone, or two or more kinds may be used in combination.

[0059] The gel polymer electrolyte may include a matrix polymer (host polymer) made of an ion-conductive polymer and the liquid electrolyte injected into the matrix polymer. Examples of the matrix polymer (host polymer) include polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyacrylonitrile (PAN), polyvinylidene fluoride - hexafluoropropylene (PVdF - HEP), polymethyl methacrylate (PMMA), and copolymers thereof.

[0060] The ionic liquid electrolyte may include an ionic liquid and the lithium salt dissolved in the ionic liquid, and may further include the additive in addition to the ionic liquid and the lithium salt. The "ionic liquid" refers to a series of compounds that are salts composed only of cations and anions and are liquid at room temperature. The cation component constituting the ionic liquid is preferably at least one selected from the group consisting of imidazolium ions, pyridinium ions, pyrrolium ions, pyrazolium ions, pyrrolinium ions, pyrrolidinium ions, piperidinium ions, triazinium ions, and ammonium ions. These cation components may or may not be substituted. Examples of the anion component constituting the ionic liquid include halide ions, nitrate ions (NO3 - ), tetrafluoroborate ions (BF4 - ), hexafluorophosphate ions (PF6 - ), (FSO2)2N - , AlCl3 - , lactate ions, and the like. Only one type of ionic liquid may be used alone, or two or more types may be used in combination.

[0061] (1.1.3) Outer package The outer package 20A houses and seals the wound electrode body 10A, the electrolytic solution, the shaft 30, the current collector tab 40A, and the current collector tab 40B.

[0062] As shown in FIG. 1, the outer package 20A includes a main body portion 21A, a lid portion 22, and a sealing member 23. The main body portion 21A houses the wound electrode body 10A, the electrolytic solution, the shaft 30, the current collector tab 40A, and the current collector tab 40B.

[0063] The main body portion 21A is a cylindrical object. The main body portion 21A has an opening that is open on the positive Y-axis side. The main body portion 21A has one protrusion 210 on its inner peripheral wall that physically contacts the insulator 13 of the wound electrode body 10A. The lid portion 22 closes the opening of the main body portion 21A. The lid portion 22 is a disk-shaped object. In the first embodiment, the materials of the main body portion 21A and the lid portion 22 are metals. Examples of the metal include iron, copper, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, manganese, and alloys thereof (such as stainless steel, brass, phosphor bronze, etc.).

[0064] The sealing member 23 electrically insulates the main body portion 21A and the lid portion 22 and fills the gap between the main body portion 21A and the lid portion 22. The material of the sealing member 23 may be a known elastomer. "Elastomer" refers to a resin having a tensile elastic modulus of less than 6.0×108 Pa at 25°C. Examples of the elastomer include urethane-based thermoplastic elastomers, amide-based thermoplastic elastomers, olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, polyester-based thermoplastic elastomers, etc.

[0065] (1.1.4) Shaft The shaft 30 functions as the winding shaft of the wound electrode body 10A. The shaft 30 may be a hollow shaft or a solid shaft. When the shaft 30 is a hollow shaft, a cooling medium may be injected into its interior. The shaft 30 may have, for example, a metal shaft and an insulating coating formed on the surface of the metal shaft. Examples of the material of the metal shaft include the metals described above. Examples of the insulating coating include the same ones as those exemplified as the resin of the insulator 13.

[0066] (1.1.5) Current Collector Tab In the first embodiment, one end of the current collector tab 40A is electrically connected to a current collector 100A (i.e., the current collector (B1) 121) located on the outermost periphery on the positive Y-axis side of the wound electrode body 10A. The other end of the current collector tab 40A is electrically connected to the lid portion 22 of the exterior body 20A. One end of the current collector tab 40B is electrically connected to a current collector 100A (i.e., the current collector (C1) 111) located on the innermost periphery on the negative Y-axis side of the wound electrode body 10A. The other end of the current collector tab 40B is electrically connected to the main body portion 21A of the exterior body 20A.

[0067] (1.2) Method for manufacturing a secondary battery The method for manufacturing the secondary battery of the first embodiment is a method for manufacturing the secondary battery 1A. The method for manufacturing the secondary battery of the present disclosure includes a first sheet preparation step, a second sheet production step, a third sheet production step, a fourth sheet production step, an electrode laminate production step, and a wound electrode body production step. The first sheet preparation step, the second sheet production step, the third sheet production step, the fourth sheet production step, the electrode laminate production step, and the wound electrode body production step are performed in this order.

[0068] (1.2.1) First sheet preparation step In the first sheet preparation step, a first sheet 51 is prepared. As shown in FIG. 6, the first sheet 51 has a current collector 100A, a positive electrode active material layer 103, and a negative electrode active material layer 102. The positive electrode active material layer 103 is laminated on the second contact portions R121 on both main surfaces of the current collector 100A. The negative electrode active material layer 102 is laminated on the first contact portions R111 on both main surfaces of the current collector 100A. The negative electrode active material layer 102 is spaced apart from the positive electrode active material layer 103 in the second direction in the Y-axis direction.

[0069] The method for preparing the first sheet 51 includes a current collector precursor preparation step, a current collector production step, and an active material layer formation step. The current collector precursor preparation step and the current collector production step are performed in this order. The active material layer formation step is performed after the current collector production step.

[0070] In the current collector precursor preparation step, a current collector precursor is prepared. The current collector precursor is the material for the current collector 100A. The method for preparing the current collector precursor is not particularly limited and may be any known method.

[0071] In the current collector manufacturing step, the current collector precursor is subjected to a stretching process or an etching process to manufacture the current collector 100A. The stretching process and the etching process may be any known methods.

[0072] In the active material layer formation step, a negative electrode active material layer 102 is formed on the first contact portions R111 on both main surfaces of the current collector 100A, and a positive electrode active material layer 103 is formed on the second contact portions R121 on both main surfaces of the current collector 100A. The formation method for each of the negative electrode active material layer 102 and the positive electrode active material layer 103 may be any known method.

[0073] (1.2.2) Second Sheet Manufacturing Step In the second sheet manufacturing step, an insulator 13a is formed in the gap GA (see FIGS. 6 and 7) between the adjacent positive electrode active material layer 103 and negative electrode active material layer 102 on both main surfaces of the first sheet 51 to manufacture the second sheet 52 shown in FIG. 7. The insulator 13a is a part of the insulator 13. The formation method of the insulator 13a is not particularly limited and is appropriately selected according to the material of the insulator 13a and may be any known method. When the material of the insulator 13a is a thermosetting resin, a solution containing the thermosetting resin may be filled in the gap GA and heated to form the insulator 13a. The second sheet is integral.

[0074] (1.2.3) Third Sheet Manufacturing Step In the third sheet manufacturing process, on both main surfaces of the second sheet 52, a separator 101 is laminated on each of the positive electrode active material layer 103 and the negative electrode active material layer 102, and an insulator 13b is formed in the gap GB (see Fig. 8) between adjacent separators 101 to manufacture the third sheet 53A shown in Fig. 8. The preparation method and lamination method of the separator 101 may be any known method. The separator 101 is welded to the positive electrode active material layer 103 or the negative electrode active material layer 102. The insulator 13b is a part of the insulator 13. The formation method of the insulator 13b is the same as that of the insulator 13a. The insulator 13a and the insulator 13b are welded together. The third sheet 53A is integrated.

[0075] (1.2.4) Fourth sheet manufacturing process In the fourth sheet manufacturing process, the exposed portion of the current collector 100A (the portion corresponding to the gap GA) located between the adjacent positive electrode active material layer 103 and negative electrode active material layer 102 of the first sheet 51 is separated from the first sheet 51, and an insulator 13c is formed in the gap GC (see Fig. 9) between the separated current collectors 122, 112 and the gap GC (see Fig. 9) between the adjacent positive electrode active material layer 103 and negative electrode active material layer 102 to manufacture the fourth sheet 54A shown in Fig. 9. The separation method of the current collector 100A is not particularly limited and may be any known method. The insulator 13c is a part of the insulator 13. The formation method of the insulator 13c is the same as that of the insulator 13a. The fourth sheet 54A is integrated.

[0076] (1.2.5) Electrode laminate manufacturing process In the electrode laminate manufacturing process, the fourth sheet 54A is laminated on the third sheet 53A to manufacture the electrode laminate 10a shown in Figs. 3 and 4. The lamination method of the fourth sheet 54A is not particularly limited and may be any known method. The separator 101 is welded to the positive electrode active material layer 103 or the negative electrode active material layer 102. The electrode laminate 10a is integrated.

[0077] (1.2.6) Wound electrode body manufacturing process In the process of manufacturing the wound electrode body, the electrode laminate 10a is wound around the axis 30 with the Y-axis as the axis to produce the wound electrode body 10A. The winding method of the electrode laminate 10a is not particularly limited, and any known method may be used.

[0078] (1.3) Function and effect As described with reference to FIGS. 1 to 9, the secondary battery 1A includes a wound electrode body 10A, an electrolytic solution, and an exterior body 20A. The wound electrode body 10A is formed by winding the electrode laminate 10a around the Y-axis. The electrode laminate 10a has a unit (A) 11, a unit (B) 12B, and an insulator 13. The unit (A) 11 includes a first laminate 110. The unit (B) 12 includes a second laminate 120. The current collector (A1) 111 and the current collector (B1) 121 are an integral current collector 100A. The insulator 13 partitions the space between the wound electrode body 10A and the exterior body 20A by contact with the exterior body 20A. As a result, two unit cells in the Y-axis direction (i.e., the winding axis) of the wound electrode body 10A are formed. The electrolytic solutions of the two unit cells are isolated by the insulator 13. That is, in the secondary battery 1A, only the Y-axis direction can be a liquid junction path. Therefore, the total area of the walls of the insulator 13 that isolates the electrolytic solutions of the plurality of unit cells is smaller than the partition area of the conventional laminated bipolar battery 900. As a result, the occurrence of liquid junction is suppressed in the secondary battery 1A.

[0079] As described with reference to FIGS. 1 to 9, in the secondary battery 1A, the thickness of the unit (A) 11 and the thickness of the unit (B) 12 are the same. The thickness L2 (see FIG. 5) of the first contact portion R111 of the current collector 100A and the thickness L3 (see FIG. 5) of the second contact portion R121 of the current collector 100A are different. The first contact portion R111 and the second contact portion R121 are each composed of one metal layer. Thus, when the secondary battery 1A is sandwiched and constrained between a pair of flat plates, the pressure applied to the part constituting the unit (A) 11 is the same as the pressure applied to the part constituting the unit (B) 12. That is, shear stress is less likely to occur in the current collectors 100A, 112, 122 and the separator 101 of the secondary battery 1A. As a result, the current collectors 100A, 112, 122 and the separator 101 are less likely to break or undergo plastic deformation. As a result, in the secondary battery 1A, the battery performance is less likely to deteriorate.

[0080] As described with reference to FIGS. 1 to 9, the method for manufacturing a secondary battery according to the first embodiment includes a first sheet preparation step, a second sheet production step, a third sheet production step, a fourth sheet production step, and an electrode laminate production step. Thus, the method for manufacturing a secondary battery according to the first embodiment can manufacture the secondary battery 1A in which the occurrence of liquid leakage is suppressed.

[0081] As described with reference to FIGS. 1 to 9, the method for manufacturing a secondary battery according to the first embodiment further includes a wound electrode body production step. Thus, the method for manufacturing a secondary battery according to the first embodiment can manufacture the secondary battery 1A in which the occurrence of liquid leakage is suppressed.

[0082] As described with reference to FIGS. 1 to 9, the method for manufacturing a secondary battery according to the first embodiment further includes a current collector precursor preparation step and a current collector production step. The thickness of the unit (A) 11 is the same as the thickness of the unit (B) 12. The thickness L2 (see FIG. 5) of the first contact portion R111 of the current collector 100A is different from the thickness L3 (see FIG. 5) of the second contact portion R121 of the current collector 100A. As a result, even when the positive electrode active material layer 103 and the negative electrode active material layer 102 are pressed, shear stress is less likely to occur in the current collector 100A. In addition, also when the electrode laminate 10a is sandwiched and constrained by a pair of gripping tools in which the portion in contact with the electrode laminate 10a is planar during the manufacturing process of the secondary battery 1A, shear stress is less likely to occur in the current collectors 100A, 112, 122 and the separator 101 of the electrode laminate 10a. As a result, the manufacturing method of the secondary battery of the first embodiment can manufacture the secondary battery 1A without breaking the current collectors 100A, 112, 122 and the separator 101, and without plastically deforming the current collectors 100A, 112, 122 and the separator 101.

[0083] (2) Second Embodiment The manufacturing method of the secondary battery of the second embodiment is a manufacturing method of the secondary battery 1A. The manufacturing method of the secondary battery of the present disclosure includes a first sheet preparation step, a second sheet production step, a third sheet production step, a separation step, a fourth sheet production step, an electrode laminate production step, and a wound electrode body production step. The first sheet preparation step, the second sheet production step, the third sheet production step, the separation step, the fourth sheet production step, the electrode laminate production step, and the wound electrode body production step are performed in this order.

[0084] (2.1) First Sheet Preparation Step In the first sheet preparation step, the first sheet 51 shown in FIG. 6 is prepared. The first sheet preparation step is the same as that exemplified as the first sheet preparation step of the first embodiment.

[0085] (2.2) Second Sheet Production Step In the second sheet production step, an insulator 13a is formed in the gap GA (see FIGS. 6 and 7) between the adjacent positive electrode active material layers 103 and negative electrode active material layers 102 on both main surfaces of the first sheet 51 to produce the second sheet 52 shown in FIG. 7. The second sheet production step is the same as that exemplified as the second sheet production step of the first embodiment.

[0086] (2.3) Third Sheet Production Step In the third sheet manufacturing process, on one main surface of the second sheet 52, a separator 101 is laminated on each of the positive electrode active material layer 103 and the negative electrode active material layer 102, and an insulator 13b is formed in a gap GB (see FIG. 10) between adjacent separators 101 to manufacture the third sheet 53B shown in FIG. 10. The method for preparing and laminating the separator 101 may be any known method. The separator 101 is welded to the positive electrode active material layer 103 or the negative electrode active material layer 102. The insulator 13b is a part of the insulator 13. The method for forming the insulator 13b is the same as the method for forming the insulator 13a. The insulator 13a and the insulator 13b are welded together. The third sheet 53B is integrated.

[0087] (2.4) Separation process In the separation process, both end portions of the third sheet 53B in the Y-axis direction are cut with a cutting line CL1 and a cutting line CL2 (that is, along the Z-axis direction) to separate the third sheet 53B into a third sheet central portion piece 530, a third sheet end portion piece 531, and a third sheet end portion piece 532. Hereinafter, the third sheet end portion piece 531 and the third sheet end portion piece 532 are also referred to as "a pair of third sheet end portion pieces 531, 532". The third sheet central portion piece 530 includes the insulator 13b. The pair of third sheet end portion pieces 531, 532 do not include the insulator 13b. The method for cutting the third sheet 53B may be any known method.

[0088] (2.5) Fourth sheet manufacturing process In the fourth sheet manufacturing process, an insulator 13c is formed in a gap GC (see FIG. 11) between current collectors 112 and 122 of a pair of third sheet end portion pieces 531, 532 and a gap GC (see FIG. 11) between adjacent positive electrode active material layers 103 and negative electrode active material layers 102 to manufacture the fourth sheet 53B shown in FIG. 11. The insulator 13c is a part of the insulator 13. The method for forming the insulator 13c is the same as the method for forming the insulator 13a. The fourth sheet 54B is integrated.

[0089] (2.6) Electrode laminate manufacturing process In the electrode laminate manufacturing process, the fourth sheet 54B is laminated on the third sheet 53B to manufacture the electrode laminate 10a shown in FIGS. 3 and 4. The method of laminating the fourth sheet 54B is not particularly limited as long as it is a known method. The separator 101 is welded to the positive electrode active material layer 103 or the negative electrode active material layer 102. The electrode laminate 10a is integrated.

[0090] (2.7) Winding type electrode body manufacturing process In the winding type electrode body manufacturing process, the electrode laminate 10a is wound around the Y-axis using the shaft 30 to manufacture the winding type electrode body 10A. The method of winding the electrode laminate 10a is not particularly limited as long as it is a known method.

[0091] (2.8) Operational effects As described with reference to FIGS. 1 to 7, FIGS. 10 and 11, the manufacturing method of the secondary battery of the second embodiment includes a first sheet preparation process, a second sheet manufacturing process, a third sheet manufacturing process, a splitting process, a fourth sheet manufacturing process, and an electrode laminate manufacturing process. Thereby, the manufacturing method of the secondary battery of the second embodiment can manufacture the secondary battery 1A in which the occurrence of liquid leakage is suppressed.

[0092] As described with reference to FIGS. 1 to 7, FIGS. 10 and 11, the manufacturing method of the secondary battery of the second embodiment further includes a current collector precursor preparation process and a current collector manufacturing process. The thickness of the unit (A) 11 is the same as the thickness of the unit (B) 12. The thickness L2 (see FIG. 5) of the first contact portion R111 of the current collector 100A is different from the thickness L3 (see FIG. 5) of the second contact portion R121 of the current collector 100A. Thereby, the manufacturing method of the secondary battery of the second embodiment can manufacture the secondary battery 1A in which the occurrence of liquid leakage is suppressed.

[0093] As described with reference to FIGS. 1 to 7, FIGS. 10 and 11, the manufacturing method of the secondary battery of the second embodiment further includes a current collector precursor preparation process and a current collector manufacturing process. The thickness of the unit (A) 11 is the same as the thickness of the unit (B) 12. The thickness L2 (see FIG. 5) of the first contact portion R111 of the current collector 100A is different from the thickness L3 (see FIG. 5) of the second contact portion R121 of the current collector 100A. As a result, even when the positive electrode active material layer 103 and the negative electrode active material layer 102 are pressed, it is difficult for shear stress to occur in the current collector 100A. In addition, also when the electrode laminate 10a is clamped and restrained by a pair of gripping tools whose portions in contact with the electrode laminate 10a are planar during the manufacturing process of the secondary battery 1A, it is difficult for shear stress to occur in the current collectors 100A, 112, 122 and the separator 101 of the electrode laminate 10a. As a result, the manufacturing method of the secondary battery according to the second embodiment can manufacture the secondary battery 1A without breaking the current collectors 100A, 112, 122 and the separator 101 and without plastically deforming the current collectors 100A, 112, 122 and the separator 101.

[0094] (3) Third Embodiment (3.1) Secondary Battery The secondary battery 1B according to the third embodiment is the same as the secondary battery 1A according to the first embodiment, except that mainly four unit cells are configured.

[0095] As shown in FIG. 12, the secondary battery 1B includes a wound electrode body 10B, an electrolytic solution (not shown), a cylindrical exterior body 20B, a shaft 30, a current collecting tab 40A, and a current collecting tab 40B.

[0096] (3.1.1) Wound Electrode Body The wound electrode body 10B is formed by winding a rectangular electrode laminate 10b twice about the Y-axis direction.

[0097] The wound electrode body 10B may be accommodated in the exterior body 20B in a state of being accommodated in an insulating packaging bag. The material of the insulating packaging bag is a resin (for example, polyethylene, polypropylene, etc.).

[0098] The electrode laminate 10b is a sheet-like material. Both main surfaces of the electrode laminate 10b are planar.

[0099] In the third embodiment, as shown in FIGS. 13 and 14, the electrode laminate 10b has two units (A) 11, two units (B) 12, and three insulators 13. As shown in FIG. 13, the two units (A) 11 and the two units (B) 12 are alternately arranged along the positive Y-axis direction. The unit (B) 12 is electrically connected in series with the unit (A) 11. The unit (B) 12 is spaced apart from the unit (A) 11 in the Y-axis direction. The insulator 13 is filled in the gap between the adjacent unit (A) 11 and the unit (B) 12.

[0100] Hereinafter, the unit (A) 11 on the negative Y-axis side is also referred to as "unit (A) 11A". The unit (A) 11 on the positive Y-axis side is also referred to as "unit (A) 11C". The unit (B) 12 on the negative Y-axis side is also referred to as "unit (B) 12B". The unit (B) 12 on the positive Y-axis side is also referred to as "unit (B) 12D".

[0101] (3.1.1.1) Unit (A) and Unit (B) In the third embodiment, in the unit (A) 11A and the unit (B) 12B, and the unit (A) 11C and the unit (B) 12D, the current collector (A1) 111 and the current collector (B1) 121 are an integrated current collector 100A, and the current collector (A2) 112 and the current collector (B2) 122 are not an integrated current collector. The current collector 100A electrically connects the unit (A) 111 and the unit (B) 121 in series. The current collector 100A electrically connects the unit (A) 112 and the unit (B) 122 in series.

[0102] In the third embodiment, in the unit (B) 12B and the unit (A) 11C, the current collector (A1) 111 and the current collector (B1) 121 are not an integrated current collector, and the current collector (A2) 112 and the current collector (B2) 122 are an integrated current collector 100B. The current collector 100B electrically connects the unit (B) 121 and the unit (A) 112 in series.

[0103] (3.1.1.2) Insulator The insulator 13 divides the space between the wound electrode body 10A and the exterior body 20A into a first space R20A, a second space R20B, a third space R20C, and a fourth space R20D by coming into contact with the exterior body 20A. In other words, the insulator 13 isolates the electrolytic solution in the first space R20A, the electrolytic solution in the second space R20B, the electrolytic solution in the third space R20C, and the electrolytic solution in the fourth space R20D. That is, the insulator 13 prevents liquid leakage.

[0104] (3.1.2) Exterior body As shown in FIG. 12, the exterior body 20B includes a main body portion 21B, a lid portion 22, and a sealing member 23. The main body portion 21B has the same configuration as the main body portion 21A, except that it has three protrusions 210 that physically contact the insulator 13 of the wound electrode body 10A on its inner peripheral wall.

[0105] (3.2) Method for manufacturing a secondary battery The method for manufacturing the secondary battery according to the third embodiment is a method for manufacturing the secondary battery 1B. The method for manufacturing the secondary battery according to the third embodiment is the same as the method for manufacturing the secondary battery according to the first embodiment, except that the electrode laminate 10b is produced instead of the electrode laminate 10a.

[0106] (3.3) Operational effects As described with reference to FIGS. 12 to 14, the secondary battery 1B includes a wound electrode body 10B, an electrolytic solution, and an exterior body 20B. The wound electrode body 10B is formed by winding an electrode laminate 10b about the Y-axis direction. The electrode laminate 10b has two units (A) 11, two units (B) 12B, and three insulators 13. The unit (A) 11 includes a first laminate 110. The unit (B) 12 includes a second laminate 120. In units (A) 11A and (B) 12B and units (A) 11C and (B) 12D, the current collector (A1) 111 and the current collector (B1) 121 are an integral current collector 100A. In units (B) 12A and (A) 11C, the current collector (A2) 112 and the current collector (B2) 122 are an integral current collector 100B. The insulator 13 partitions the space between the wound electrode body 10B and the exterior body 20B by contact with the exterior body 20B. Accordingly, in the secondary battery 1B, similar to the secondary battery 1A, the occurrence of a liquid junction is suppressed.

[0107] As described with reference to FIGS. 12 to 14, in the secondary battery 1B, the thickness of the unit (A) 11 and the thickness of the unit (B) 12 are the same. The thickness L2 (see FIG. 5) of the first contact portion R111 of the current collector 100A and the thickness L3 (see FIG. 5) of the second contact portion R121 of the current collector 100A are different. The first contact portion R111 and the second contact portion R121 are each formed of one metal layer. Accordingly, in the secondary battery 1B, similar to the secondary battery 1A, the battery performance is less likely to deteriorate.

[0108] As described with reference to FIGS. 12 to 14, in the secondary battery 1B, the electrode laminate 10b has two units (A) 11, two units (B) 12, and three insulators 13. The unit (A) 11 and the unit (B) 11B are alternately arranged along the Y-axis direction. Accordingly, the secondary battery 1B has four single battery layers. Each of the four single battery layers is connected in series. As a result, the secondary battery 1B can have a higher output voltage than the secondary battery 1A in which each of the two single battery layers is connected in series.

[0109] As described with reference to FIGS. 12 to 14, the method for manufacturing a secondary battery according to the third embodiment includes a first sheet preparation step, a second sheet production step, a third sheet production step, a fourth sheet production step, and an electrode laminate production step. Thereby, the method for manufacturing a secondary battery according to the third embodiment can manufacture the secondary battery 1B in which the occurrence of a liquid junction is suppressed.

[0110] As described with reference to FIGS. 12 to 14, the method for manufacturing a secondary battery according to the third embodiment further includes a wound electrode body production step. Thereby, the method for manufacturing a secondary battery according to the third embodiment can manufacture the secondary battery 1B in which the occurrence of a liquid junction is suppressed.

[0111] As described with reference to FIGS. 12 to 14, the method for manufacturing a secondary battery according to the third embodiment further includes a current collector precursor preparation step and a current collector production step. The thickness of the unit (A) 11 and the thickness of the unit (B) 12 are the same. The thickness L2 (see FIG. 5) of the first contact portion R111 of the current collector 100A and the thickness L3 (see FIG. 5) of the second contact portion R121 of the current collector 100A are different. Thereby, the method for manufacturing a secondary battery according to the third embodiment can manufacture the secondary battery 1B without breaking the current collectors 100A, 100B, 112, 122 and the separator 101, and without causing plastic deformation to the current collectors 100A, 100B, 112, 122 and the separator 101, in the same manner as the method for manufacturing a secondary battery according to the third embodiment.

[0112] As described with reference to FIGS. 12 to 14, in the secondary battery 1B, the electrode laminate 10b has two units (A) 11, two units (B) 12, and three insulators 13. The unit (A) 11 and the unit (B) 11B are alternately arranged along the Y-axis direction. As a result, the manufacturing method of the secondary battery according to the third embodiment can manufacture the secondary battery 1B having four single cell layers. Each of the four single cell layers is connected in series. As a result, the manufacturing method of the secondary battery according to the third embodiment can manufacture the secondary battery 1B having a higher output voltage than the secondary battery 1A in which each of the two single cell layers is connected in series.

[0113] (4) Fourth Embodiment (4.1) Secondary Battery The secondary battery 1C according to the fourth embodiment is mainly the same as the secondary battery 1A according to the first embodiment, except that the configuration of the current collector is different.

[0114] The secondary battery 1C includes a wound electrode body 10C, an electrolytic solution (not shown), a cylindrical exterior body 20B, a shaft 30, a current collecting tab 40A, and a current collecting tab 40B.

[0115] The wound electrode body 10C has the same configuration as the wound electrode body 10A, except that a current collector 100C is used instead of the current collector 100A.

[0116] As shown in FIG. 15, the current collector 100C is a clad material. The current collector 100C includes a portion 100C1 made of a first metal and a portion 100C2 made of a second metal. The thickness L3 (the length L3 in the Z-axis direction) of the portion 100C2 is thicker than the thickness L2 (the length L2 in the Z-axis direction) of the portion 100C1. The type of the first metal and the type of the second metal are different. Examples of the first metal and the second metal are the same as those exemplified as the above-mentioned metals.

[0117] (4.2) Manufacturing Method of Secondary Battery The manufacturing method of the secondary battery according to the fourth embodiment is the same as the manufacturing method of the secondary battery according to the first embodiment, except that the current collector precursor preparation step and the current collector manufacturing step are different.

[0118] The manufacturing method of the secondary battery according to the fourth embodiment includes a first sheet preparation step, a second sheet production step, a third sheet production step, a fourth sheet production step, an electrode laminate production step, and a wound electrode body production step. The manufacturing method of the secondary battery according to the fourth embodiment is the same as the manufacturing method of the secondary battery according to the first embodiment, except that the method of preparing the first sheet 51 in the first sheet preparation step is different.

[0119] In the fourth embodiment, the method of preparing the first sheet 51 includes a current collector production step and an active material layer formation step. The active material layer formation step is the same as the active material layer formation step of the first embodiment.

[0120] In the current collector production step of the fourth embodiment, a current collector 100C composed of two metal layers is produced. The method of producing the current collector 100C may be any method of producing a known clad material.

[0121] (4.3) Operational effects As described with reference to FIG. 15, the secondary battery 1C has the same configuration as the wound electrode body 10A, except that the current collector 100C is used instead of the current collector 100A. Thereby, in the secondary battery 1C, the occurrence of liquid junction is suppressed, as in the secondary battery 1A.

[0122] As described with reference to FIG. 15, in the secondary battery 1C, the thickness of the unit (A) 11 is the same as the thickness of the unit (B) 12. The thickness L2 of the first contact portion R111 of the current collector 100A is different from the thickness L3 of the second contact portion R121 of the current collector 100A. The first contact portion R111 and the second contact portion R121 are composed of two metal layers. Thereby, in the secondary battery 1C, the battery performance is less likely to deteriorate, as in the secondary battery 1A.

[0123] As described with reference to FIG. 15, the manufacturing method of the secondary battery according to the fourth embodiment includes a first sheet preparation step, a second sheet production step, a third sheet production step, a fourth sheet production step, and an electrode laminate production step. As a result, the manufacturing method of the secondary battery according to the fourth embodiment can manufacture the secondary battery 1C in which the occurrence of liquid leakage is suppressed.

[0124] As described with reference to FIG. 15, the manufacturing method of the secondary battery according to the fourth embodiment further includes a wound electrode body manufacturing step. As a result, the manufacturing method of the secondary battery according to the fourth embodiment can manufacture the secondary battery 1C in which the occurrence of liquid leakage is suppressed.

[0125] As described with reference to FIG. 15, the manufacturing method of the secondary battery according to the fourth embodiment further includes a current collector manufacturing step. The thickness of the unit (A) 11 is the same as the thickness of the unit (B) 12. The thickness L2 (see FIG. 15) of the first contact portion R111 of the current collector 100A is different from the thickness L3 (see FIG. 15) of the second contact portion R121 of the current collector 100A. As a result, the manufacturing method of the secondary battery according to the fourth embodiment can manufacture the secondary battery 1C without breaking the current collectors 100C, 112, 122 and the separator 101 and without causing plastic deformation to the current collectors 100C, 112, 122 and the separator 101, in the same manner as the manufacturing method of the secondary battery according to the first embodiment.

[0126] (5) Fifth Embodiment (5.1) Secondary Battery The secondary battery 1D according to the fifth embodiment is the same as the secondary battery 1A according to the first embodiment, except that the configuration of the current collector is different mainly.

[0127] The secondary battery 1D includes a wound electrode body 10D, an electrolytic solution (not shown), a cylindrical exterior body 20B, a shaft 30, a current collecting tab 40A, and a current collecting tab 40B.

[0128] The wound electrode body 10D has the same configuration as the wound electrode body 10A, except that the current collector 100D is used instead of the current collector 100A.

[0129] As shown in Fig. 16, the current collector 100D has a metal foil 100D1 with a constant thickness and metal layers 100D2 formed on a part of both main surfaces of the metal foil 100D1. The metal layer 100D2 is in contact with the positive electrode active material layer 103 and not in contact with the negative electrode active material layer 102. In the Y-axis direction, a gap same as the gap between the unit (A) 12A and the unit (B) 12B is formed between the metal layer 100D2 and the negative electrode active material layer 102. That is, the sealing property of the interface between the metal layer 100D2 and the insulator 13 is ensured. Thereby, the occurrence of ion short circuit is suppressed. The thickness L3 (the thickness L3 in the Z-axis direction) of the second contact part R121 of the metal layer 100D is thicker than the thickness L2 (the thickness L2 in the Z-axis direction) of the first contact part R111 of the metal layer 100D. The type of material of the metal foil 100D1 is different from the type of material of the metal layer 100D2. Examples of the material of the metal foil 100D1 and the material of the metal layer 100D2 are the same as those exemplified as the above-mentioned metals.

[0130] (5.2) Method for manufacturing a secondary battery The method for manufacturing a secondary battery according to the fifth embodiment is the same as the method for manufacturing a secondary battery according to the first embodiment except that the current collector manufacturing process is different.

[0131] The method for manufacturing a secondary battery according to the fifth embodiment includes a first sheet preparation process, a second sheet manufacturing process, a third sheet manufacturing process, a fourth sheet manufacturing process, an electrode laminate manufacturing process, and a wound electrode body manufacturing process. The method for manufacturing a secondary battery according to the fifth embodiment is the same as the method for manufacturing a secondary battery according to the first embodiment except that the method for preparing the first sheet 51 in the first sheet preparation process is different.

[0132] In the fifth embodiment, the method for preparing the first sheet 51 includes a current collector precursor preparation process, a current collector manufacturing process, and an active material layer formation process. The current collector precursor preparation process is the same as the current collector precursor preparation process according to the first embodiment. The active material layer formation process is the same as the active material layer formation process according to the first embodiment.

[0133] In the current collector manufacturing process of the fifth embodiment, at least one of electrolytic plating and electroless plating is performed on the current collector precursor to manufacture the current collector 100D. The electrolytic plating and electroless plating may be any known methods.

[0134] (5.3) Operational Effects As described with reference to FIG. 16, the secondary battery 1D has the same configuration as the wound electrode body 10A, except that the current collector 100D is used instead of the current collector 100A. Thus, in the secondary battery 1D, the occurrence of liquid leakage is suppressed, similar to the secondary battery 1A.

[0135] As described with reference to FIG. 16, in the secondary battery 1C, the thickness of the unit (A) 11 is the same as the thickness of the unit (B) 12. The thickness L2 of the first contact portion R111 of the current collector 100A and the thickness L3 of the second contact portion R121 of the current collector 100A are different. The first contact portion R111 and the second contact portion R121 are composed of two metal layers. Thus, in the secondary battery 1D, the battery performance is less likely to deteriorate, similar to the secondary battery 1A.

[0136] As described with reference to FIG. 16, the manufacturing method of the secondary battery of the fifth embodiment includes a first sheet preparation step, a second sheet manufacturing step, a third sheet manufacturing step, a fourth sheet manufacturing step, and an electrode laminate manufacturing step. Thus, the manufacturing method of the secondary battery of the fifth embodiment can manufacture the secondary battery 1D in which the occurrence of liquid leakage is suppressed.

[0137] As described with reference to FIG. 16, the manufacturing method of the secondary battery of the fifth embodiment further includes a wound electrode body manufacturing step. Thus, the manufacturing method of the secondary battery of the fifth embodiment can manufacture the secondary battery 1D in which the occurrence of liquid leakage is suppressed.

[0138] As described with reference to FIG. 16, the method for manufacturing a secondary battery according to the fifth embodiment further includes a current collector manufacturing step. The thickness of the unit (A) 11 is the same as the thickness of the unit (B) 12. The thickness L2 (see FIG. 16) of the first contact portion R111 of the current collector 100A is different from the thickness L3 (see FIG. 16) of the second contact portion R121 of the current collector 100A. Thus, similar to the method for manufacturing a secondary battery according to the first embodiment, the method for manufacturing a secondary battery according to the fifth embodiment can manufacture the secondary battery 1D without breaking the current collectors 100D, 112, 122 and the separator 101 and without causing plastic deformation to the current collectors 100D, 112, 122 and the separator 101.

[0139] (6) Modification In the first to fifth embodiments, the thickness L2 (see FIG. 5) of the first contact portion R111 of the current collector 100A is thinner than the thickness L3 (see FIG. 5) of the second contact portion R121 of the current collector 100A. However, the present disclosure is not limited thereto. The thickness L2 may be thicker than the thickness L3, or the thickness L2 and the thickness L3 may be the same.

[0140] In the first to fifth embodiments, the thickness of the unit (A) 11 is the same as the thickness of the unit (B) 12. However, the present disclosure is not limited thereto. The thickness of the unit (A) 11 and the thickness of the unit (B) 12 may be different.

[0141] In the first, second, fourth, and fifth embodiments, the current collector (A1) 111 and the current collector (B1) 121 are an integral current collector 100A, and the current collector (A2) 112 and the current collector (B2) 122 are not an integral current collector. However, the present disclosure is not limited thereto. The current collector (A1) 111 and the current collector (B1) 121 may not be an integral current collector, and the current collector (A2) 112 and the current collector (B2) 122 may be an integral current collector.

[0142] The manufacturing method of the secondary battery according to the third to fifth embodiments is a method according to the manufacturing method of the secondary battery according to the first embodiment, but the present disclosure is not limited thereto. The manufacturing method of the secondary battery according to the third to fifth embodiments may be a method according to the manufacturing method of the secondary battery according to the second embodiment.

Claims

1. A wound electrode body, an electrolytic solution, an exterior body housing the wound electrode body and the electrolytic solution, and comprising the wound electrode body is formed by winding a rectangular electrode laminate extending in a first direction and a second direction orthogonal to the first direction about the second direction as an axis, the electrode laminate comprises at least one unit (A), at least one unit (B) electrically connected in series with the unit (A) and spaced from the unit (A) in the second direction, and at least one insulator filled in a gap between the adjacent unit (A) and unit (B), and having the unit (A) includes a first laminate formed by laminating a separator, a negative electrode active material layer, a current collector (A1), the negative electrode active material layer, the separator, a positive electrode active material layer, a current collector (A2), and the positive electrode active material layer in this order along a third direction orthogonal to the first direction and the second direction, the unit (B) includes a second laminate formed by laminating the separator, the positive electrode active material layer, a current collector (B1), the positive electrode active material layer, the separator, the negative electrode active material layer, a current collector (B2), and the negative electrode active material layer in this order along the third direction, the current collector (A1) and the current collector (B1) are an integral current collector, or the current collector (A2) and the current collector (B2) are an integral current collector, the insulator partitions a space between the wound electrode body and the exterior body by contact with the exterior body. A secondary battery.

2. the thickness of the unit (A) is the same as the thickness of the unit (B), the thickness of a first contact portion of the current collector with the negative electrode active material layer is different from the thickness of a second contact portion of the current collector with the positive electrode active material layer, At least one of the first contact portion and the second contact portion is of a first configuration or a second configuration, The first configuration consists of one metal layer, The secondary battery according to claim 1, wherein the second configuration consists of at least two metal layers.

3. The at least one unit (A) is a plurality of the units (A), The at least one unit (B) is a plurality of the units (B), The at least one insulator is a plurality of insulators, The secondary battery according to claim 1 or claim 2, wherein the unit (A) and the unit (B) are alternately arranged along the second direction.

4. A method for manufacturing the secondary battery according to claim 1, comprising: Preparing a first sheet having the current collector, the positive electrode active material layer laminated on a part of both main surfaces of the current collector, and the negative electrode active material layer spaced apart from the positive electrode active material layer in the second direction and laminated on a part of both main surfaces of the current collector; Forming the insulator in a gap between the adjacent positive electrode active material layer and negative electrode active material layer on both main surfaces of the first sheet to produce a second sheet; Laminating the separator on each of the positive electrode active material layer and the negative electrode active material layer on both main surfaces of the second sheet, and forming the insulator in a gap between the adjacent separators to produce a third sheet; Separating the exposed portion of the current collector located between the adjacent positive electrode active material layer and negative electrode active material layer of the first sheet from the first sheet, and forming the insulator in the gap between the separated current collectors and in the gap between the adjacent positive electrode active material layer and negative electrode active material layer to produce a fourth sheet; Laminating the fourth sheet on the third sheet to produce the electrode laminate; A method for manufacturing a secondary battery, comprising the above steps.

5. A method for manufacturing the secondary battery according to claim 1, comprising: Prepare a first sheet having the current collector, the positive electrode active material layer laminated on a part of both main surfaces of the current collector, the negative electrode active material layer spaced apart from the positive electrode active material layer in the second direction and laminated on a part of both main surfaces of the current collector. Form the insulator in a gap between the adjacent positive electrode active material layer and negative electrode active material layer on both main surfaces of the first sheet to produce a second sheet. Laminating the separator on each of the positive electrode active material layer and the negative electrode active material layer on one main surface of the second sheet, and forming the insulator in a gap between adjacent separators to produce a third sheet. Cut both end portions of the third sheet in the second direction along the third direction to separate the third sheet into a third sheet central portion piece including the insulator and a pair of third sheet end portions pieces not including the insulator. Form the insulator in a gap between the current collectors of the pair of third sheet end portions pieces and in a gap between the adjacent positive electrode active material layer and negative electrode active material layer to produce a fourth sheet. Laminating the fourth sheet on the third sheet central portion piece to produce the electrode laminate. A method for manufacturing a secondary battery, including the above steps.

6. The method for manufacturing a secondary battery according to claim 4 or claim 5, further including winding the electrode laminate around the second direction as an axis to produce the wound electrode body.

7. The thickness of the unit (A) is the same as the thickness of the unit (B). The thickness of the first contact portion of the current collector with the negative electrode active material layer is different from the thickness of the second contact portion of the current collector with the positive electrode active material layer. Prepare a current collector precursor. The method for manufacturing a secondary battery according to claim 4 or claim 5, further including performing at least one of a stretching treatment, an etching treatment, an electrolytic plating treatment, and an electroless plating treatment on the first contact portion or the second contact portion of the current collector precursor to produce the current collector.

8. The thickness of the unit (A) is the same as the thickness of the unit (B), The thickness of the first contact portion of the current collector with the negative electrode active material layer is different from the thickness of the second contact portion of the current collector with the positive electrode active material layer, The method for manufacturing a secondary battery according to claim 4 or claim 5, further comprising manufacturing the current collector composed of at least two metal layers.

9. The at least one unit (A) is a plurality of the units (A), The at least one unit (B) is a plurality of the units (B), The at least one insulator is a plurality of insulators, The method for manufacturing a secondary battery according to claim 4 or claim 5, wherein the unit (A) and the unit (B) are alternately arranged along the second direction.

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