Secondary batteries

Abstract

A secondary battery according to the present invention is provided with: an electrode assembly which is obtained by stacking at least one electrode constituent layer that comprises a positive electrode, a negative electrode and a separator; and an outer package which covers the electrode assembly. With respect to this secondary battery, a collector which extends from the positive electrode and / or the negative electrode of the electrode assembly protrudes as an electrode lead from the outer package; the entirety of one main surface of a protrusion part of the collector, the protrusion part protruding from the outer package, is covered with a resin member; and at least a part of the collector is held by the resin member within the outer package.

Description

[Technical Field]

[0001] The present disclosure relates to a secondary battery, and more particularly to a secondary battery having an electrode assembly including electrode constituent layers including a positive electrode, a negative electrode, and a separator. [Background technology]

[0002] Secondary batteries are so-called storage batteries that can be repeatedly charged and discharged, and are used in a variety of applications, including mobile devices such as mobile phones, smartphones, and laptops. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-526802 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present invention have realized that conventional secondary batteries have problems that need to be overcome, and have found the need to take measures to address these problems. Specifically, the inventors have found the following problems:

[0005] For example, Patent Document 1 discloses a secondary battery in which electrode leads protrude outward from the battery case.

[0006] 19, for example, a conventional secondary battery 100 is configured such that an electrode lead 111 electrically connected to an electrode assembly 110 protrudes outward (to the right) from a battery case 120 (for example, a battery case that may be composed of a first case 120a (upper case) and a second case 120b (lower case)). The electrode lead 111 is generally provided with an insulating member (for example, an insulating member that may be composed of a first insulating member 112a (upper insulating member) and a second insulating member 112b (lower insulating member)), and the electrode lead 111 is sandwiched between these insulating members from above and below to fix the electrode lead 111 and ensure sealing.

[0007] In a conventional secondary battery 100 having such a configuration, stress was concentrated at the part indicated by the arrow in Figure 19, particularly at the base of the protruding electrode lead, during and / or during use, and there was a risk that the electrode lead 111 would break.

[0008] The present disclosure has been made in view of the above-mentioned problems. That is, a main object of the present disclosure is to provide a secondary battery having reinforced electrode leads. [Means for solving the problem]

[0009] In order to achieve the above object, in one embodiment of the present disclosure, The battery includes an electrode assembly formed by laminating at least one electrode-constituting layer including a positive electrode, a negative electrode, and a separator, and an exterior body that covers the electrode assembly, a current collector extending from the positive electrode and / or the negative electrode of the electrode assembly protrudes from the exterior body as an electrode lead, an entirety of one main surface of the protruding portion of the current collector protruding from the exterior body is covered with a resin member; The secondary battery is provided in which at least a portion of the current collector is sandwiched between the resin members inside the exterior body. [Effects of the Invention]

[0010] The present disclosure provides a secondary battery with reinforced electrode leads. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view that schematically shows the configuration of an electrode assembly. [Figure 2] FIG. 2 is a schematic diagram illustrating the concept of the secondary battery of the present disclosure. [Figure 3] FIG. 3 is a schematic diagram showing a secondary battery according to an embodiment of the present disclosure (first embodiment). [Figure 4] FIG. 4 is a schematic view illustrating the production of a secondary battery according to the first embodiment of the present disclosure. [Figure 5] FIG. 5 is a schematic diagram showing a part of the internal structure of the secondary battery according to the first embodiment of the present disclosure. [Figure 6A] FIG. 6A is a schematic diagram illustrating the internal structure (particularly the resin member) of the secondary battery according to the first embodiment of the present disclosure. [Figure 6B] FIG. 6B is a schematic diagram illustrating the internal structure (particularly the resin member) of the secondary battery according to the first embodiment of the present disclosure. [Figure 7] FIG. 7 is a schematic diagram illustrating the internal structure (particularly the electrode assembly) of the secondary battery according to the first embodiment of the present disclosure. [Figure 8] FIG. 8 is a schematic cross-sectional view showing a cross section in the width direction of the secondary battery according to the first embodiment of the present disclosure. [Figure 9] FIG. 9 is a schematic cross-sectional view showing a longitudinal cross section of the secondary battery according to the first embodiment of the present disclosure. [Figure 10] FIG. 10 is a schematic diagram showing a secondary battery according to another embodiment of the present disclosure (second embodiment). [Figure 11] FIG. 11 is a schematic cross-sectional view showing a longitudinal cross section of a secondary battery according to a second embodiment of the present disclosure. [Figure 12] FIG. 12 is a schematic diagram showing a secondary battery according to another embodiment of the present disclosure (third embodiment). [Figure 13] FIG. 13 is a schematic cross-sectional view showing a longitudinal cross section of a secondary battery according to a third embodiment of the present disclosure. [Figure 14A] FIG. 14A is a schematic cross-sectional view showing a typical usage form of the secondary battery according to the first embodiment of the present disclosure. [Figure 14B] FIG. 14B is a schematic cross-sectional view that schematically shows a mode of use of the secondary battery according to the first embodiment of the present disclosure. [Figure 15A] FIG. 15A is a schematic cross-sectional view showing a typical usage form of a secondary battery according to a second embodiment of the present disclosure. [Figure 15B] FIG. 15B is a schematic cross-sectional view showing a typical usage form of the secondary battery according to the second embodiment of the present disclosure. [Figure 16A] FIG. 16A is a schematic cross-sectional view showing a typical usage form of a secondary battery according to a third embodiment of the present disclosure. [Figure 16B] FIG. 16B is a schematic cross-sectional view showing a typical usage form of the secondary battery according to the third embodiment of the present disclosure. [Figure 17] FIG. 17 is a schematic diagram showing a secondary battery according to another embodiment of the present disclosure (fourth embodiment). [Figure 18] FIG. 18 is a schematic view showing a secondary battery according to still another embodiment of the present disclosure (fifth embodiment). [Figure 19] FIG. 19 is a schematic cross-sectional view showing a conventional secondary battery. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described in more detail below with reference to a secondary battery according to an embodiment of the present disclosure. While the description will be made with reference to drawings as needed, the various elements in the drawings are merely shown schematically and illustratively to facilitate understanding of the present disclosure, and the appearance and / or dimensional ratios may differ from those of the actual product. Hereinafter, the above-described secondary battery will be referred to as the "secondary battery of the present disclosure" or simply as the "secondary battery."

[0013] The "cross-sectional view" directly or indirectly described in this specification is basically based on a virtual cross section of a secondary battery cut along the stacking direction or overlapping direction of the electrode assembly or electrode constituent layers that constitute the secondary battery (see Figure 1). Similarly, the "thickness" direction directly or indirectly described in this specification is basically based on the stacking direction of the electrode materials that constitute the secondary battery. For example, in the case of a "secondary battery having a plate-like thickness," the "thickness" direction corresponds to the plate thickness direction of such a secondary battery. The "planar view" or "planar view shape" used in this specification is based on a sketch of an object viewed from above or below along the thickness direction (i.e., the above-mentioned stacking direction).

[0014] Furthermore, the terms "upper-lower direction" and "left-right direction" used directly or indirectly in this specification correspond to the upper-lower direction and left-right direction in the drawings, respectively. Unless otherwise specified, the same reference numerals or symbols indicate the same members or parts or the same meanings. In a preferred embodiment, the stacking direction of the electrode assembly can correspond to the upper-lower direction, and the vertically downward direction (i.e., the direction in which gravity acts) can be considered to correspond to the "downward direction," and the opposite direction to that can be considered to correspond to the "upward direction."

[0015] [Basic structure of secondary batteries] The term "secondary battery" as used herein refers to a battery that can be repeatedly charged and discharged. Therefore, the secondary battery of the present disclosure is not limited to the name, and may also include, for example, an electricity storage device.

[0016] The secondary battery of the present disclosure includes an electrode assembly formed by laminating at least one electrode component layer, for example, including a positive electrode, a negative electrode, and a separator. For example, FIG. 1 schematically illustrates an electrode assembly 10. As shown in the figure, a positive electrode 1 and a negative electrode 2 may be stacked with a separator 3 interposed therebetween to form an electrode component layer 5. The electrode assembly may be formed by laminating at least one such electrode component layer 5. In FIG. 1, the electrode component layer 5 has a planar laminated structure in which the electrode component layer 5 is laminated in a planar manner. In a secondary battery, such an electrode assembly may be covered with an outer casing together with an electrolyte (e.g., a non-aqueous electrolyte). Note that the structure of the electrode assembly is not necessarily limited to a planar laminated structure. For example, the electrode assembly may have a wound laminated structure. Alternatively, the electrode assembly may have a so-called stack-and-folded structure in which a positive electrode, a separator, and a negative electrode are laminated on a long film and then folded.

[0017] The positive electrode may be composed of at least a positive electrode material layer and a positive electrode current collector. For example, the positive electrode may have a positive electrode material layer provided on at least one side of the positive electrode current collector. The positive electrode material layer contains a positive electrode active material as an electrode active material. For example, each of the multiple positive electrodes in the electrode assembly may have a positive electrode material layer provided on both sides of the positive electrode current collector, or may have a positive electrode material layer provided on only one side of the positive electrode current collector. The positive electrode current collector may have, for example, a foil form. In other words, the positive electrode current collector may be composed of a metal foil.

[0018] The negative electrode may be composed of at least a negative electrode material layer and a negative electrode current collector. For example, the negative electrode may have a negative electrode material layer provided on at least one side of the negative electrode current collector. The negative electrode material layer contains a negative electrode active material as an electrode active material. For example, each of the multiple negative electrodes in the electrode assembly may have a negative electrode material layer provided on both sides of the negative electrode current collector, or may have a negative electrode material layer provided on only one side of the negative electrode current collector. The negative electrode current collector may have, for example, a foil form. In other words, the negative electrode current collector may be composed of a metal foil.

[0019] The electrode active materials that can be contained in the positive electrode material layer and the negative electrode material layer, i.e., the positive electrode active material and the negative electrode active material, are substances that can directly participate in the transfer of electrons in a secondary battery, and are the main substances of the positive electrode and the negative electrode that are responsible for charging and discharging, i.e., the battery reaction.

[0020] More specifically, ions can be introduced into the electrolyte due to the "positive electrode active material that can be contained in the positive electrode material layer" and the "negative electrode active material that can be contained in the negative electrode material layer." These ions move between the positive electrode and the negative electrode, transferring electrons and enabling charging and discharging.

[0021] The positive electrode material layer and the negative electrode material layer may be layers capable of absorbing and releasing lithium ions, in particular. In other words, the secondary battery according to an embodiment of the present disclosure may be a non-aqueous electrolyte secondary battery in which lithium ions can move between the positive electrode and the negative electrode via the non-aqueous electrolyte to charge and discharge the battery.

[0022] When lithium ions are involved in charging and discharging, the secondary battery according to an embodiment of the present disclosure may correspond to a so-called “lithium ion battery.” In a lithium ion battery, the positive electrode and the negative electrode have layers capable of absorbing and releasing lithium ions.

[0023] The positive electrode active material of the positive electrode layer may be composed of, for example, granules, and the positive electrode layer may contain a binder to ensure better contact between the particles and to maintain the shape. The positive electrode layer may also contain a conductive additive to facilitate smoother transfer of electrons that promote the battery reaction.

[0024] The negative electrode active material of the negative electrode material layer may be composed of, for example, granules, and the negative electrode material layer may contain a binder to ensure better contact between the particles and to maintain the shape. The negative electrode material layer may also contain a conductive additive to facilitate smoother transfer of electrons that promote the battery reaction.

[0025] Because they contain a plurality of components, the positive electrode material layer and the negative electrode material layer can also be referred to as a "positive electrode composite layer" and a "negative electrode composite layer", respectively.

[0026] The positive electrode active material may be, for example, a material that contributes to the absorption and desorption of lithium ions. From this perspective, the positive electrode active material may be, for example, a lithium-containing composite oxide. More specifically, the positive electrode active material may be a lithium transition metal composite oxide containing lithium and at least one transition metal selected from the group consisting of cobalt, nickel, manganese, and iron.

[0027] In other words, the positive electrode layer of the secondary battery according to an embodiment of the present disclosure may contain such a lithium transition metal composite oxide as a positive electrode active material, for example, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, or a material in which part of the transition metal in any of these materials is replaced with another metal.

[0028] Such positive electrode active materials may be contained as a single species, or may be contained in combination of two or more species.

[0029] The binder that can be contained in the positive electrode layer is not particularly limited, but examples thereof include polymer compounds, etc. Specific examples include at least one selected from the group consisting of styrene-butadiene rubber, polyacrylic acid, polyimide resin, polyamide-imide resin, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, and polytetrafluoroethylene.

[0030] The conductive additive that can be contained in the positive electrode layer is not particularly limited, but may include at least one selected from the group consisting of carbon black such as thermal black, furnace black, channel black, ketjen black, and acetylene black; carbon fibers such as graphite, carbon nanotubes, and vapor-grown carbon fibers; metal powders such as copper, nickel, aluminum, and silver; and polyphenylene derivatives.

[0031] The thickness of the positive electrode layer is not particularly limited, but may be 1 μm or more and 300 μm or less, for example, 5 μm or more and 200 μm or less. The thickness of the positive electrode layer is the thickness inside the secondary battery, and may be the average value of measurements taken at any 10 points.

[0032] The negative electrode active material may be a material that contributes to the absorption and desorption of lithium ions, such as various carbon materials, oxides, and / or lithium alloys, metallic lithium, etc.

[0033] Examples of various carbon materials for the negative electrode active material include at least one selected from the group consisting of graphite (specifically, natural graphite and / or artificial graphite), hard carbon, soft carbon, and / or diamond-like carbon, etc. Graphite, in particular, has high electronic conductivity and, for example, excellent adhesion to the negative electrode current collector.

[0034] The oxide of the negative electrode active material may be at least one selected from the group consisting of silicon oxide, tin oxide, indium oxide, zinc oxide, and lithium oxide.

[0035] Such oxides may have an amorphous structure, since this makes them less susceptible to degradation due to inhomogeneities such as grain boundaries or defects.

[0036] The lithium alloy of the negative electrode active material may be any alloy of a metal that can form an alloy with lithium, and may be, for example, a binary, ternary, or higher alloy of lithium with a metal such as Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, or La.

[0037] Such alloys may have an amorphous structure, since this makes them less susceptible to degradation due to inhomogeneities such as grain boundaries or defects.

[0038] The binder that can be contained in the negative electrode material layer is not particularly limited, but examples thereof include polymer compounds, etc. Specific examples include at least one selected from the group consisting of styrene-butadiene rubber, polyacrylic acid, polyimide resin, polyamide-imide resin, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, and polytetrafluoroethylene.

[0039] The conductive additive that can be contained in the negative electrode material layer is not particularly limited, but may include at least one selected from the group consisting of carbon black such as thermal black, furnace black, channel black, ketjen black, and acetylene black; carbon fibers such as graphite, carbon nanotubes, and vapor-grown carbon fibers; metal powders such as copper, nickel, aluminum, and silver; and polyphenylene derivatives.

[0040] The thickness of the negative electrode layer is not particularly limited, but may be 1 μm or more and 300 μm or less, for example, 5 μm or more and 200 μm or less. The thickness of the negative electrode layer is the thickness inside the secondary battery, and the average value of measurements taken at any 10 points may be used.

[0041] The positive electrode current collector and the negative electrode current collector that can be used for the positive electrode and the negative electrode are components that can collect and supply electrons generated in the electrode active material due to the battery reaction. Such electrode current collectors may be sheet-shaped metal components. Also, such electrode current collectors may be porous or perforated. For example, the current collectors may be plates, metal foils, punched metals, meshes, expanded metals, etc.

[0042] The positive electrode current collector that can be used for the positive electrode may be made of a metal foil containing at least one selected from the group consisting of aluminum, stainless steel (SUS), nickel, etc. The positive electrode current collector may be, for example, an aluminum foil.

[0043] The negative electrode current collector that can be used for the negative electrode may be made of a metal foil containing at least one selected from the group consisting of copper, stainless steel (SUS), nickel, etc. The negative electrode current collector may be, for example, a copper foil.

[0044] In the present disclosure, "stainless steel" (SUS) refers to, for example, stainless steel as defined in "JIS G 0203 Iron and Steel Terminology," and may be an alloy steel containing chromium or chromium and nickel.

[0045] The thickness of each of the positive electrode current collector and the negative electrode current collector is not particularly limited, but may be 1 μm or more and 150 μm or less, for example, 1 μm or more and 100 μm or less. The thickness of each of the positive electrode current collector and the negative electrode current collector is the thickness inside the secondary battery, and may be the average value of measurements taken at any 10 points.

[0046] The separator that can be used for the positive electrode and the negative electrode is a member that can be provided from the viewpoint of preventing a short circuit due to contact between the positive electrode and the negative electrode, retaining an electrolyte, etc. In other words, the separator can be said to be a member that prevents electronic contact between the positive electrode and the negative electrode while allowing ions to pass through.

[0047] For example, the separator may be a porous or microporous insulating member, and may have a membrane form due to its small thickness. By way of example only, a microporous membrane made of polyolefin may be used as the separator.

[0048] The microporous membrane that can be used as the separator may contain, for example, only polyethylene (PE) or only polypropylene (PP) as the polyolefin. Furthermore, the separator may be a laminate that can be composed of a "microporous membrane made of PE" and a "microporous membrane made of PP." The surface of the separator may be covered with an inorganic particle coating layer and / or an adhesive layer. The surface of the separator may have adhesive properties.

[0049] The thickness of the separator is not particularly limited, but may be 1 μm or more and 100 μm or less, for example, 2 μm or more and 30 μm or less. The thickness of the separator is the thickness inside the secondary battery (particularly the thickness between the positive electrode and the negative electrode), and the average value of measurements taken at any 10 points may be used.

[0050] In the present disclosure, the separator should not be limited to a particular name, and may be a solid electrolyte, a gel electrolyte, and / or insulating inorganic particles that can have a similar function.

[0051] In a secondary battery according to an embodiment of the present disclosure, for example, an electrode assembly including at least one stacked electrode component layer including a positive electrode, a negative electrode, and a separator may be covered with an outer casing together with an electrolyte. The electrolyte can assist the migration of metal ions released from the electrodes (positive electrode and / or negative electrode). The electrolyte may be, for example, a "non-aqueous" electrolyte containing a non-aqueous or organic electrolyte and / or solvent, or an "aqueous" electrolyte containing water.

[0052] For example, when the positive electrode and the negative electrode have layers capable of absorbing and releasing lithium ions, the electrolyte may be a lithium-ion-containing electrolyte or a "non-aqueous" electrolyte (hereinafter referred to as a "nonaqueous electrolyte") that includes a non-aqueous or organic electrolyte and / or a solvent. That is, the electrolyte may be a non-aqueous electrolyte. Metal ions released from the electrodes (positive electrode and / or negative electrode) are present in the electrolyte, and therefore, the electrolyte can assist the migration of metal ions in the battery reaction.

[0053] A secondary battery according to an embodiment of the present disclosure may be a non-aqueous electrolyte secondary battery that uses a non-aqueous electrolyte containing a non-aqueous solvent and a solute as the electrolyte. The electrolyte may be in a liquid or gel form (note that in this specification, a liquid non-aqueous electrolyte is also referred to as a "nonaqueous electrolyte solution").

[0054] The non-aqueous electrolyte may be an electrolyte containing a non-aqueous solvent and a solute. A specific solvent for the non-aqueous electrolyte may contain at least a carbonate. The carbonate may be a cyclic carbonate and / or a chain carbonate.

[0055] Although not particularly limited, examples of cyclic carbonates include at least one selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC) and vinylene carbonate (VC).

[0056] The chain carbonates may include at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and dipropyl carbonate (DPC).

[0057] For example, in one preferred embodiment of the present disclosure, the non-aqueous electrolyte may be a combination of cyclic carbonates and chain carbonates, such as a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC), a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC), etc. Specific examples of the solute of the non-aqueous electrolyte include Li salts such as LiPF6 and / or LiBF4.

[0058] In this disclosure, the "exterior body" of a secondary battery generally refers to a member capable of covering an electrode assembly in which at least one electrode component layer including a positive electrode, a negative electrode, and a separator is laminated. The exterior body may be made of an electrically conductive or electrically conductive exterior body. Alternatively, the exterior body may be made of a laminate film or the like.

[0059] In the present disclosure, "electrode lead" means a conductive member that can be electrically connected to the positive electrode and / or negative electrode of an electrode assembly, and can protrude or extend from the electrode assembly. Such electrode leads may extend from the "positive electrode current collector" and / or "negative electrode current collector" described above, and may be integrally formed from the same material as such current collectors.

[0060] In the present disclosure, the above configuration may be appropriately changed or modified as needed.

[0061] [Features of the Secondary Battery Disclosed Herein]

[0062] The inventors attempted to solve the above problems by taking a new approach rather than simply extending the conventional technology, and as a result, they have invented a secondary battery that achieves the above-mentioned main object.

[0063] In conventional secondary batteries, it has been found that stress concentrates, for example, at the portion indicated by the arrow in Fig. 19, particularly at the base portion of the protruding electrode lead 111, during and / or during use, and that the protruding portion of the electrode lead 111 is bent up or down, for example, along dashed line L, causing the electrode lead 111 to break. In other words, it has been found that the electrode lead 111 breaks when the edges of the two upper and lower insulating members (112a, 112b) are aligned with each other along dashed line L shown in Fig. 19. It has been found that the electrode lead 111 breaks easily, particularly when the electrode lead 111 is made of a very thin member such as metal foil.

[0064] Therefore, the inventors of the present invention have considered reinforcing the electrode leads by covering the protruding portions of the electrode leads with a resin member (see FIG. 2).

[0065] As a result of extensive research, we have found that the electrode lead can be reinforced by covering the protruding portion of the electrode lead with a resin member, and that during use, as shown in Figures 14A and 14B, the electrode lead (28) reinforced with the resin member (30a) can be placed on the circuit (50) of the substrate (S) (Figure 14A), and the electrode lead (28) can be electrically connected to the circuit (50) using solder (60) or the like (see Figure 14B).In this case, the base portion of the electrode lead (28) (the portion on the battery body side) remains reinforced with the resin member (30a), and it has been found that the electrode lead (28) is sufficiently reinforced (see Figure 14B).

[0066] The secondary battery of the present disclosure basically comprises an electrode assembly formed by laminating at least one electrode component layer including a positive electrode, a negative electrode, and a separator, and an exterior body that covers the electrode assembly.

[0067] For example, as shown in Fig. 2, in a secondary battery according to an embodiment of the present disclosure, a current collector that may extend from the positive electrode and / or negative electrode of an electrode assembly (not shown) may protrude as an electrode lead (28) from an exterior body (40) (more specifically, an exterior body that may be composed of a first exterior sheet 40a and a second exterior sheet 40b, which will be described in detail below). For convenience of explanation, only one electrode lead (28) is shown in Fig. 2, but in a secondary battery according to the present disclosure, two electrode leads (a positive electrode lead and a negative electrode lead) may protrude (see Fig. 17).

[0068] In a secondary battery according to an embodiment of the present disclosure, for example, one main surface of the protruding portion (P) of the current collector that can protrude from the exterior body (40) may be entirely covered with the resin member (30).

[0069] In this disclosure, "electrode lead" (28) generally refers to a conductive member that can be electrically connected to a positive electrode or a negative electrode that can be included in an electrode assembly.

[0070] In this disclosure, the "protrusion" (P) generally refers to the portion of the "electrode lead" (28) that protrudes from the exterior body in a "plan view" or "top view."

[0071] The electrode lead 28 has one main surface at the protruding portion P entirely covered with, and preferably supported by, the resin member 30, thereby reinforcing the electrode lead 28, particularly the protruding portion P. This configuration significantly reduces damage or breakage of the electrode lead 28, particularly the protruding portion P, due to bending (see FIG. 19).

[0072] In the secondary battery of the present disclosure, such a resin member (30) may extend beyond the protruding portion (P) of the electrode lead (28).

[0073] In addition, in a secondary battery according to an embodiment of the present disclosure, at least a portion of the current collector may be sandwiched between a resin member (30) inside or within the exterior body (40) (see FIG. 9). With this configuration, a portion of the electrode lead (28), more specifically, the base portion of the protrusion (P), can be supported by the resin member (30) within the battery body.

[0074] The secondary battery of the present disclosure can be used in various fields, particularly in the field of electrical and electronic devices. In the secondary battery of the present disclosure, at least one main surface of the protruding portion (P) of the electrode lead (28) is entirely covered with a resin member (30) for reinforcement (see FIG. 2). With this configuration, as shown in FIG. 14, for example, by placing the electrode lead (28) on a circuit (50) provided on a desired substrate (S), an electrical contact can be formed between the electrode lead (28) and the circuit (50) (see FIG. 14(A)).

[0075] In the embodiment shown in Figure 14, a resin film (30a) is disposed on the electrode lead (28) as the resin member (30), and by applying "solder" (60) from above, it is possible to fix the electrical contact that may be formed between the electrode lead (28) and the circuit (50). At this time, a portion of the resin film (30a) (for example, the portion indicated by the dashed line in Figure 14(B)) may be melted and removed by heat. This configuration can provide an improved electrical connection between the electrode lead (28) and the circuit (50).

[0076] The resin member may be composed of two or more layers, for example, as shown in FIGS. 3 and 4, and may include, for example, two resin films (30a, 30b) (see FIG. 4).

[0077] (First embodiment) 3 shows a secondary battery 101 according to the first embodiment of the present disclosure. For ease of explanation, the resin member includes two resin films, specifically, a first resin film 30a and a second resin film 30b. This configuration allows the electrode lead 28 to be reinforced more simply and reliably.

[0078] The secondary battery 101 according to the first embodiment includes a first exterior sheet 40a and a second exterior sheet 40b as an exterior body. In the secondary battery of the present disclosure, the first exterior sheet 40a and the second exterior sheet 40b may be formed by folding and arranging a single exterior sheet as shown in Fig. 3. Alternatively, the exterior body may be bag-shaped or pouch-shaped.

[0079] The structure of the secondary battery 101 according to the first embodiment, particularly the internal structure of the secondary battery 101, will be described with reference to Figures 4 to 9. Note that the secondary battery of the present disclosure should not be interpreted as being limited to the form shown in the drawings.

[0080] First, a method for manufacturing the secondary battery 101 according to the first embodiment will be briefly described with reference to FIG.

[0081] The secondary battery 101 according to the first embodiment includes an electrode assembly 20. The electrode assembly 20 will be described in detail below with reference to, for example, FIG. For ease of explanation, the electrode assembly 20 is illustrated as being formed by laminating a positive electrode layer 21 (more specifically, a positive electrode layer including a first positive electrode material layer 21a, a second positive electrode material layer 21b, and a positive electrode current collector 26), a negative electrode layer 22 (more specifically, two negative electrode layers (a "first negative electrode layer" including a first negative electrode material layer 22a and a first negative electrode current collector 27a, and a "second negative electrode layer" including a second negative electrode material layer 22b and a second negative electrode current collector 27b), and a separator 23 (more specifically, a first separator 23a and a second separator 23b). The electrode assembly 20 may be configured in various ways as long as it functions as a battery. For example, the positive electrode layer 21 may be configured as a negative electrode layer, and the negative electrode layer 22 may be configured as a positive electrode layer. The number of layers may also be varied as appropriate.

[0082] A positive electrode lead (28) may protrude from a positive electrode current collector (26) that may be included in the electrode assembly 20 (hereinafter, sometimes referred to as an "electrode lead" or simply a "lead" without distinguishing between positive and negative). The positive electrode lead (28) may be formed from the same material as the positive electrode current collector 26. Alternatively, the positive electrode lead (28) may be formed as a separate member from a different material, and such a separate member may be electrically connected to the positive electrode current collector 26. There are no particular limitations on the shape of the positive electrode lead (28), and it may be, for example, plate-like, or preferably strip-like.

[0083] 4 and 5, a resin member may be disposed around the electrode assembly 20, particularly around the peripheral edge of the electrode assembly 20. More specifically, a first resin film 30a and a second resin film 30b may be disposed around the peripheral edge of the electrode assembly 20.

[0084] In the present disclosure, the "peripheral edge of the electrode assembly" generally refers to the part of the electrode assembly excluding the main surfaces. For example, if the electrode assembly has a plate-like shape with two main surfaces, it refers to the surface excluding these two main surfaces.

[0085] The first resin film 30a and the second resin film 30b may have a first opening 31a and a second opening 31b, respectively, through which the main body portion of the electrode assembly 20 can be positioned (see FIG. 5).

[0086] In the present disclosure, the main body portion of the electrode assembly generally refers to the laminated structure portion of the electrode assembly excluding the electrode leads and the like.

[0087] 5 shows a state in which the main body of the electrode assembly 20 is positioned in the first opening 31a of the first resin film 30a and the second opening 31b of the second resin film 30b. At this time, at least a portion of the positive electrode lead 28 that can extend from the positive electrode current collector 26 is sandwiched between the first resin film 30a and the second resin film 30b, and the remaining portion can be supported by the first resin film 30a as a protruding portion (P).

[0088] The positional relationship between the positive electrode current collector 26 and the first resin film 30a is shown in FIG. 6A. The relationship between the first resin film 30a and the second resin film 30b is shown in FIG. 6B. The first resin film 30a and the second resin film 30b may be integrated to form the resin member 30. In this case, the first opening 31a of the first resin film 30a and the second opening 31b of the second resin film 30b may be joined together to form a single opening 31. For ease of explanation, the positive electrode current collector 26 is omitted from FIG. 6B.

[0089] As will be described in detail below, the first resin film 30a and / or the second resin film 30b may have heat-sealing properties, and the first resin film 30a and the second resin film 30b can be bonded to each other by such heat-sealing (see Figure 6B).

[0090] 7 shows a schematic diagram of the configuration of the electrode assembly 20. The electrode assembly 20 generally has a positive electrode layer, a negative electrode layer, and a separator positioned therebetween. In other words, the electrode assembly 20 has at least one electrode layer.

[0091] More specifically, the electrode assembly 20 may have a positive electrode current collector 26, from which a positive electrode lead 28 extends. The positive electrode lead 28 may be made of the same material as the positive electrode current collector 26 or a different material. From the perspective of producing a thin secondary battery, it is preferable that the positive electrode current collector 26 and the positive electrode lead 28 are both made of metal foil. The first positive electrode material layer 21a and the second positive electrode material layer 21b may be arranged to sandwich the positive electrode current collector 26. Furthermore, a first separator 23a may be arranged so as to be interposed between the first positive electrode material layer 21a and the first negative electrode material layer 22a. A second separator 23b may be arranged so as to be interposed between the second positive electrode material layer 21b and the second negative electrode material layer 22b. The first negative electrode current collector 27a may be disposed so as to directly face the first negative electrode material layer 22a, and the second negative electrode current collector 27b may be disposed so as to directly face the second negative electrode material layer 22b.

[0092] The positive electrode current collector 26, the first positive electrode material layer 21a, and the second positive electrode material layer 21b may be collectively referred to as the "positive electrode layer" (21). Only one of the first positive electrode material layer 21a and the second positive electrode material layer 21b may be disposed.

[0093] The first negative electrode material layer 22a and the first negative electrode current collector 27a may be collectively referred to as the "first negative electrode layer." The second negative electrode material layer 22b and the second negative electrode current collector 27b may be collectively referred to as the "second negative electrode layer." In the present disclosure, the "first negative electrode layer" and the "second negative electrode layer" may also be collectively referred to as the "negative electrode layer" (22).

[0094] Only one of the "first negative electrode layer" and the "second negative electrode layer" may be disposed.

[0095] The configuration of the electrode assembly 20 should not be construed as being limited to the above.

[0096] For example, a widthwise cross section (VIII-VIII) of the secondary battery 101 shown in Fig. 3 is shown typically in Fig. 8, and a longitudinal (or vertical) cross section (IX-IX) is shown typically in Fig. 9. Figs. 3, 8, and 9 are schematic views of the secondary battery 101 of the first embodiment, and the appearance and / or dimensional ratios may differ from the actual product.

[0097] For example, by arranging the first exterior sheet 40a and the second exterior sheet 40b so as to abut against the electrode assembly 20 and / or the resin member 30 (specifically, the first resin film 30a and the second resin film 30b) (see FIG. 4) and pressing them while heating, it is possible to produce the secondary battery 101 of the first embodiment as shown in FIG. 3. In this case, steps may be formed on the edges of the surfaces of the first exterior sheet 40a and the second exterior sheet 40b (see FIG. 3), but such steps are not an essential configuration of the present invention and may or may not be present.

[0098] The "exterior body," "resin member," and "electrode lead" will be described in detail below.

[0099] (exterior body) The exterior body is, for example, a part or member that can be arranged opposite the two main surfaces of the electrode assembly, and generally has a plate-like, preferably sheet-like, shape. When the exterior body has a sheet-like shape, it may be made of one sheet or two sheets.

[0100] For example, as shown in Fig. 4, the exterior body may be composed of two exterior sheets, for example, a first exterior sheet 40a and a second exterior sheet 40b. For convenience of explanation, the lower sheet will be referred to as the "first exterior sheet" and the upper sheet will be referred to as the "second exterior sheet." There are no particular limitations on the shapes of the first exterior sheet and the second exterior sheet when viewed from above, and they may be rectangular as shown in the figure, or any other geometric shape other than rectangular.

[0101] The first and second exterior sheets may each independently be made of a metal plate, a clad material, or a laminate film. The first and second exterior sheets may be made of the same type of material or different types of materials. If the same type of material is used, the first and second exterior sheets may be continuous. Such an exterior body can be formed by folding the same material. The exterior body may also be in the form of a bag or pouch.

[0102] The "metal plate" can be any plate- or strip-shaped material made of aluminum, copper, stainless steel (SUS), nickel, or the like, without any particular limitations.

[0103] In the metal plate, "stainless steel" (SUS) refers to, for example, stainless steel as defined in "JIS G 0203 Iron and Steel Terminology," and may be an alloy steel containing chromium or chromium and nickel.

[0104] In this disclosure, the term "plate-like" refers to a structure having two parallel or nearly parallel main surfaces. In this disclosure, the term "strip-like" refers to a structure having two parallel or nearly parallel main surfaces, a longitudinal direction, and a width direction perpendicular to the longitudinal direction.

[0105] The thickness of the metal plate is, for example, not less than 0.01 mm and not more than 0.250 mm.

[0106] In this disclosure, the term "clad material" refers to a member made by simultaneously rolling and bonding multiple metal materials.

[0107] The clad material may be made of, for example, at least two metal materials selected from the group consisting of aluminum, copper, stainless steel (SUS), and nickel.

[0108] The overall thickness of the clad material is, for example, 0.01 mm or more and 0.250 mm or less.

[0109] The term "laminate film" generally refers to a laminated structure. Examples of laminate films include a laminate film consisting of a metal sheet (a metal sheet that may be made of the above-mentioned metal plate or clad material, etc.), a fusion layer (a fusion layer that may be made of a resin member, particularly a resin sheet, as described in detail below), and a protective layer (a protective layer that may be made of a polymer material, etc.), and a laminate film in which the above-mentioned metal plate or clad material is covered with a resin member, particularly a resin sheet, as described in detail below. When the above-mentioned metal plate or clad material is used as a resin member, particularly a laminate film in which a resin sheet, as described in detail below, is used, the presence of the resin member, as described in detail below, may be omitted.

[0110] The total thickness of the laminate film is, for example, 0.06 mm or more and 0.30 mm or less.

[0111] The exterior body is preferably made of a metal plate or a clad material. When the exterior body is made of a metal plate or a clad material, the exterior body may be electrically connected to the positive electrode or negative electrode of the electrode assembly and may function as a positive electrode terminal or a negative electrode terminal.

[0112] 3, the first exterior sheet 40a is electrically connected to the first negative electrode layer (specifically, the first negative electrode current collector 27a) of the electrode assembly 20, and the second exterior sheet 40b is electrically connected to the second negative electrode layer (specifically, the second negative electrode current collector 27b) of the electrode assembly 20 (see FIG. 8). This allows both the first exterior sheet 40a and the second exterior sheet 40b to function as negative electrode terminals.

[0113] When the exterior body is made of a laminate film, the positive electrode lead 28 and the negative electrode lead 29 may each be made to protrude from the exterior body, as shown in FIG. 17, for example.

[0114] (Resin parts) In this disclosure, the term "resin member" broadly refers to a member that can be made of a resin material or an elastomer material, and in a narrow sense refers to a member that can be made of a resin material or an elastomer material that has "insulating properties." It is preferable that the resin member have not only "insulating properties" but also "thermal fusion properties" (or thermal adhesive properties).

[0115] It is more preferable that the resin member contains a resin having "insulating properties" and "thermal adhesive properties."

[0116] In the present disclosure, "insulating" broadly means electrical insulating property, and narrowly means insulating property that can prevent electrical short circuit between the electrode assembly, particularly the positive electrode and the negative electrode.

[0117] In the present disclosure, "thermally adhesive" generally means the property of exhibiting adhesiveness when heated.

[0118] The resin member having both "insulating properties" and "thermal adhesive properties" improves the insulating properties and sealing properties for the electrode assembly, and the bonding properties for the exterior body.

[0119] The resin member can be a thermoplastic resin, preferably a heat-sealable resin. Examples of the thermoplastic resin include polyolefin resins such as polyethylene and / or polypropylene, preferably polypropylene and its copolymers. Examples of the resin member can include a single-layer film of a thermoplastic resin or a multilayer film containing a thermoplastic resin. An example of a multilayer film is a multilayer heat-sealable film in which both sides of a high-melting-point resin layer serving as an intermediate layer are sandwiched between low-melting-point resin layers (thermoplastic resin layers). Examples of the elastomer material include a polyester-based thermoplastic elastomer.

[0120] From another perspective, the resin member may contain an adhesive component that exhibits insulating properties. Examples of such adhesives include acrylic adhesives such as acrylate copolymers, rubber adhesives such as natural rubber, silicone adhesives such as silicone rubber, urethane adhesives such as urethane resins, α-olefin adhesives, ether adhesives, ethylene-vinyl acetate resin adhesives, epoxy resin adhesives, vinyl chloride resin adhesives, chloroprene rubber adhesives, cyanoacrylate adhesives, aqueous polymer-isocyanate adhesives, styrene-butadiene rubber adhesives, nitrile rubber adhesives, nitrocellulose adhesives, reactive hot melt adhesives, phenolic resin adhesives, modified silicone adhesives, polyamide resin adhesives, polyimide adhesives, polyurethane resin adhesives, polyolefin resin adhesives, polyvinyl acetate resin adhesives, polystyrene resin solvent-based adhesives, polyvinyl alcohol adhesives, polyvinylpyrrolidone resin adhesives, polyvinyl butyral resin adhesives, polybenzimidazole adhesives, polymethacrylate resin adhesives, melamine resin adhesives, urea resin adhesives, and / or resorcinol adhesives.

[0121] The resin member may have the form of a film, that is, the resin member may have the form of a membrane, i.e., a thin plate.

[0122] There is no particular limitation on the thickness of the resin member. For example, as shown in FIG. 9, it is preferable that the total thickness (T1) of the current collector and the two resin films is smaller than the total thickness (T0) of the secondary battery (T1). <T0)。

[0123] The resin member may be two resin films that extend inside the exterior body and are bonded to each other (see FIGS. 2 and 4 to 6B). Such a configuration can further improve the airtightness of the electrode assembly.

[0124] As the resin member, at least a portion of each of the two resin films may be bonded to the exterior body (see FIG. 3). With this configuration, the sealing performance of the secondary battery can be further improved.

[0125] The resin members may be two resin films each having an opening, with the electrode assembly positioned inside this opening (see FIGS. 4 to 6B). There are no particular restrictions on the position where the opening is formed in the resin film. Furthermore, such an opening may or may not be present. The presence of an opening allows for the secondary battery to be made smaller, particularly thinner.

[0126] (electrode lead) The secondary battery of the present disclosure has a positive electrode lead that can be electrically connected to a positive electrode that can be included in an electrode assembly and / or a negative electrode lead that can be electrically connected to a negative electrode that can be included in an electrode assembly.

[0127] In this disclosure, the term "positive electrode lead" refers to a conductor that can be electrically connected to a positive electrode that can be included in an electrode assembly. In this disclosure, the term "negative electrode lead" refers to a conductor that can be electrically connected to a negative electrode that can be included in an electrode assembly. The material constituting such a conductor is not particularly limited and may be selected from the group consisting of, for example, aluminum, copper, stainless steel (SUS), nickel, etc. The positive electrode lead may be an extension of the positive electrode current collector or a separate member made from the above-mentioned materials. The negative electrode lead may be an extension of the negative electrode current collector or a separate member made from the above-mentioned materials. Either one or both of the positive electrode lead and / or negative electrode lead may be present. There are no particular limitations on the shape of the positive electrode lead and / or negative electrode lead. From the viewpoint of forming a thin battery, the positive electrode lead and / or negative electrode lead are preferably in the form of a strip or film.

[0128] There is no particular limitation on the thickness of the electrode leads such as the positive electrode lead and / or the negative electrode lead, and it is, for example, from 0.005 mm to 0.15 mm, preferably from 0.01 mm to 0.10 mm.

[0129] There are no particular limitations on the longitudinal dimension of the electrode leads such as the positive electrode lead and / or the negative electrode lead, and it is, for example, 5 mm or more and 50 mm or less, and preferably 10 mm or more and 30 mm or less.

[0130] There are no particular limitations on the width of the electrode leads such as the positive electrode lead and / or the negative electrode lead, and it is, for example, from 0.1 mm to 15 mm, preferably from 1 mm to 10 mm.

[0131] Each component in the first embodiment may be modified as needed.

[0132] (Second embodiment) A secondary battery 102 according to a second embodiment of the present disclosure is shown in a schematic perspective view of FIG. 10 and a schematic cross-sectional view in the longitudinal direction (XI-XI) (see FIG. 11).

[0133] In the second embodiment, the entirety of one main surface of the protrusion (or electrode lead) of the current collector may be covered with one of the two resin films (specifically, the first resin film 30a), and at least a portion of the other main surface of the protrusion may be covered with the other of the two resin films (specifically, the second resin film 30b1).

[0134] The second embodiment may be configured similarly to the first embodiment except for the second resin film 30b1 (see FIGS. 3 and 10).

[0135] Specifically, the second resin film 30b1 of the second embodiment is characterized in that its longitudinal dimension is different from that of the second resin film 30b of the first embodiment. More specifically, the second resin film 30b1 of the second embodiment may extend from the exterior body toward the tip of the electrode lead 28 along the electrode lead 28.

[0136] For example, as shown in FIG. 11, the longitudinal dimension (L a ) of the second resin film 30b1 in the longitudinal direction (L b ) ratio (L b / La ) may be greater than or equal to 0 and less than 1, for example, greater than or equal to 0 and less than 1 / 2.

[0137] With this configuration, the electrode lead 28 (protrusion P) is sandwiched between the first resin film 30a and the second resin film 30b1, and the electrode lead 28 can be further reinforced.

[0138] (Third embodiment) A secondary battery 103 according to a third embodiment of the present disclosure is shown in a schematic perspective view of FIG. 12 and a schematic cross-sectional view in the longitudinal direction (XIII-XIII) (see FIG. 13).

[0139] In the third embodiment, both surfaces of the protruding portion of the current collector (or the electrode lead) may be completely covered with two resin films (specifically, the first resin film 30a and the second resin film 30b2).

[0140] The third embodiment may be configured similarly to the first embodiment except for the second resin film 30b2 (see FIGS. 3 and 12).

[0141] Specifically, the second resin film 30b2 of the third embodiment is characterized in that the longitudinal dimension thereof is different from that of the second resin film 30b of the first embodiment. More specifically, the longitudinal dimension of the second resin film 30b2 of the third embodiment is different from the longitudinal dimension (L a ) (see FIG. 13).

[0142] With this configuration, the electrode lead 28 (protrusion P) is completely covered and sandwiched between the first resin film 30a and the second resin film 30b2, and the electrode lead 28 can be further reinforced.

[0143] (Use of the secondary battery of the present disclosure) 14A and 14B schematically show how the secondary battery 101 (see FIGS. 3 to 9) according to the first embodiment of the present disclosure is used.

[0144] FIG. 14A shows a state in which an electrode lead 28 is placed on a circuit 50 provided on a substrate S, such as a printed circuit board. The surface of the electrode lead 28 that is not in contact with the circuit 50 is completely covered with a first resin film 30a (see FIGS. 3 and 14A). With this configuration, the electrode lead 28 is reinforced by the first resin film 30a when forming contact with the circuit 50, thereby preventing damage or breakage of the electrode lead 28. FIG. 14B shows a state in which an electrical contact that can be formed between the electrode lead 28 and the circuit 50 is fixed using solder 60. During bonding using solder, part of the first resin film 30a may be dissolved and removed. This state allows for better electrical contact to be formed between the electrode lead 28 and the circuit 50.

[0145] 15A and 15B schematically show how the secondary battery 102 (see FIGS. 10 and 11) according to the second embodiment of the present disclosure is used.

[0146] FIG. 15A shows a state in which an electrode lead 28 is placed on a circuit 50 provided on a substrate S. The surface of the electrode lead 28 that is not in contact with the circuit 50 is completely covered with a first resin film 30a. The surface of the electrode lead 28 that is in contact with the circuit 50 is also covered with a second resin film 30b1 (see FIGS. 10 and 15A). With this configuration, the electrode lead 28 is reinforced by the first resin film 30a and the second resin film 30b1 when forming contact with the circuit 50, further preventing damage or breakage of the electrode lead 28. FIG. 15B shows a state in which an electrical contact that may be formed between the electrode lead 28 and the circuit 50 is fixed using solder 60, as in the first embodiment. Even in this state, the electrode lead 28 is protected by being sandwiched between two resin films (30a, 30b1), thereby preventing damage or breakage of the electrode lead 28.

[0147] 16A and 16B schematically show how the secondary battery 103 (see FIGS. 12 and 13) according to the third embodiment of the present disclosure is used.

[0148] FIG. 16A shows a state in which a second resin film 30b2 covering an electrode lead 28 is placed on a circuit 50 provided on a substrate S. The other surface of the electrode lead 28 is completely covered by the first resin film 30a. With this configuration, the electrode lead 28 is completely covered and reinforced by the first resin film 30a and the second resin film 30b2, preventing damage or breakage of the electrode lead 28 from both sides. The second resin film 30b2 also enhances adhesion to the circuit 50. FIG. 16B shows a state in which an electrical path is formed between the electrode lead 28 and the circuit 50 using solder 60. In this state, a portion of the first resin film 30a is removed by heat, exposing the electrode lead 28. The exposed electrode lead 28 can then be electrically connected to the circuit 50. Furthermore, electricity can be passed between the electrode lead 28 and the circuit 50 from the side or end surface via the solder 60. Even in such a state, the electrode lead 28 is protected by being sandwiched between the two resin films (30a, 30b2), and therefore damage or breakage of the electrode lead 28 can be suppressed.

[0149] (Fourth embodiment) In the first to third embodiments, for convenience of explanation, only one electrode lead is shown (see FIGS. 3 to 13), but two electrode leads (a positive electrode lead and a negative electrode lead) may be provided. For example, FIG. 17 schematically shows a secondary battery 104 of a fourth embodiment. The secondary battery 104 basically has the same configuration as the secondary battery 101 of the first embodiment, but includes a positive electrode lead 28 and a negative electrode lead 29. The positive electrode lead 28 can correspond to the electrode lead 28 of the first embodiment. The negative electrode lead 29 is a member that can extend from a negative electrode, particularly a negative electrode current collector, that can be included in an electrode assembly, similar to the electrode lead 28 of the first embodiment.

[0150] (Fifth embodiment) For example, Fig. 18 schematically shows a secondary battery 105 of the fifth embodiment. The secondary battery 105 basically has the same configuration as the secondary battery 102 of the second embodiment (see Fig. 10), but includes a positive electrode lead 28 and a negative electrode lead 29'. The positive electrode lead 28 can correspond to the positive electrode lead 28 of the fourth embodiment (see Fig. 17). The negative electrode lead 29' can also correspond to the negative electrode lead 29 of the fourth embodiment (see Fig. 17).

[0151] (Sixth embodiment) Similar to the fourth and fifth embodiments, the secondary battery 103 of the third embodiment (see FIG. 12) may also be provided with two electrode leads (a positive electrode lead and a negative electrode lead) (sixth embodiment (not shown)).

[0152] The components in the first to sixth embodiments may be used in appropriate combinations as needed.

[0153] The secondary batteries according to the first to sixth embodiments of the present disclosure can significantly reinforce the electrode leads. Furthermore, the handling properties are improved and the connection resistance is reduced during use. Furthermore, insulating materials such as sealants, which have conventionally been required, are no longer necessary (see FIG. 19), further simplifying the configuration of the secondary battery.

[0154] The present disclosure will be further explained in detail below with reference to examples and comparative examples. [Example]

[0155] Example 1 Copper plates (T: 0.04 mm x W: 25 mm x L: 50 mm) were used as the exterior sheets (40a, 40b).

[0156] An electrode assembly similar to the configuration shown in FIG. 7 was prepared (W: 18 mm×L: 40 mm). Second negative electrode current collector 27b: Copper foil (thickness: 12 μm) Second negative electrode layer 22b: graphite (thickness: 48 μm) Second separator 23b: Polypropylene / Polyethylene (Thickness: 30 μm) Second positive electrode layer 21b: lithium cobalt oxide (thickness: 50 μm) Positive electrode current collector 26: Aluminum foil (thickness: 30 μm) First positive electrode layer 21a: lithium cobalt oxide (thickness: 50 μm) First separator 23a: Polypropylene / Polyethylene (Thickness: 30 μm) First negative electrode layer 22a: graphite (thickness: 48 μm) First negative electrode current collector 27a: Copper foil (thickness: 12 μm)

[0157] The dimensions of the positive electrode lead 28 were T: 0.03 mm x W: 5 mm x L: 23 mm.

[0158] A resin film having the shape shown in FIG. 4 was prepared as a resin member used in the examples and comparative examples. First resin film 30a: polyolefin resin (T: 0.1 mm × W: 25 mm × L: 50 mm) Second resin film 30b: Polyolefin resin (T: 0.1 mm × W: 25 mm × L: 50 mm

[0159] The dimensions of the fabricated secondary battery shown in FIG. 9 were as follows: L a :15mm T0: 0.390mm T1: 0.230mm

[0160] (Comparative Example 1) The dimension L of the first resin film 30a of the secondary battery shown in FIG. a A secondary battery of Comparative Example 1 was fabricated in the same manner as in Example 1, except that the length of the lead wire was set to 0 mm (no protrusion).

[0161] (evaluation) The secondary batteries produced in Example 1 and Comparative Example 1 were evaluated by the following cycle test.

[0162] (Cycle test) A cycle test was carried out, with the following steps (1) and (2) being one cycle. (1) Bend the electrode lead 90 degrees (2) Return the bent electrode lead to its original position. The number of cycles required for the electrode lead to break was determined, and the results are shown in the table below. The number of cycles shown in the table below is the average value of three cycle tests.

[0163] [Table 1]

[0164] The results shown in Table 1 demonstrate that the electrode leads of the secondary battery of Example 1 are significantly reinforced (5 times or more the number of cycles).

[0165] The present disclosure may take the following forms. <1> The battery includes an electrode assembly formed by laminating at least one electrode-constituting layer including a positive electrode, a negative electrode, and a separator, and an exterior body that covers the electrode assembly, a current collector extending from the positive electrode and / or the negative electrode of the electrode assembly protrudes from the exterior body as an electrode lead, an entirety of one main surface of the protruding portion of the current collector protruding from the exterior body is covered with a resin member; At least a portion of the current collector is sandwiched between the resin members inside the exterior body. <2> The resin member comprises two resin films. <1> The secondary battery according to claim 1. <3> one main surface of the protrusion of the current collector is entirely covered with one of the two resin films, and at least a portion of the other main surface of the protrusion is covered with the other of the two resin films; <2> The secondary battery according to claim 1. <4> Both surfaces of the protrusion of the current collector are completely covered with the two resin films. <2> or <3> The secondary battery according to claim 1. <5> The total thickness of the current collector and the two resin films is smaller than the entire thickness of the secondary battery. <2> ~ <4> 10. The secondary battery according to claim 9, <6> The resin member comprises a resin having insulating properties and thermal adhesive properties. <1> ~ <5> 10. The secondary battery according to claim 9, <7> The resin member comprises a polyolefin resin. <1> ~ <6> 10. The secondary battery according to claim 9, <8> The two resin films extend inside the exterior body and are bonded to each other. <2> ~ <7> 10. The secondary battery according to claim 9, <9> At least a portion of each of the two resin films is bonded to the exterior body. <2> ~ <8> 10. The secondary battery according to claim 9, <10> The two resin films each have an opening, and the electrode assembly is positioned inside the opening. <2> ~ <9> 10. The secondary battery according to claim 9, <11> The exterior body is made of a metal plate, a clad material, or a laminate film. <1> ~ <10> 10. The secondary battery according to claim 9, <12> the exterior body is made of a metal plate or a clad material, and the exterior body is electrically connected to the positive electrode or the negative electrode of the electrode assembly; <1> ~ <11> 10. The secondary battery according to claim 9, [Industrial Applicability]

[0166] The secondary battery of the present disclosure can be used in various fields where electricity storage is conceivable. By way of example only, the secondary battery of the present disclosure can be used in the electrical, information, and communications fields where electrical and electronic devices can be used (for example, electrical and electronic devices or mobile devices including mobile phones, smartphones, laptop computers, digital cameras, activity monitors, arm computers, electronic paper, wearable devices, and small electronic devices such as RFID tags, card-type electronic money, and smart watches), household and small industrial applications (for example, power tools, golf carts, and household, nursing care, and industrial robots), large industrial applications (for example, forklifts, elevators, and harbor cranes), transportation systems (for example, hybrid cars, electric cars, buses, trains, electrically assisted bicycles, and electric motorcycles), power system applications (for example, various power generation systems, road conditioners, smart grids, and general household installation-type power storage systems), medical applications (medical devices such as earphones and hearing aids), pharmaceutical applications (dose management systems), as well as the IoT field and space and deep-sea applications (for example, space probes, submersible research vessels, and the like). [Explanation of symbols]

[0167] 1 positive electrode 2 negative electrode 3 Separator 5 Electrode composition layer 10,20,110 electrode assembly 21 Positive electrode layer 21a First cathode material layer 21b Second cathode material layer 22 negative electrode layer 22a First negative electrode material layer 22b Second negative electrode material layer 23 Separator 23a First separator 23b Second separator 26 Positive electrode current collector 27 Negative electrode current collector 27a First negative electrode current collector 27b Second negative electrode current collector 28 Electrode lead (positive lead) 29 Electrode lead (negative electrode lead) 30 Resin parts 30a First resin film 30b Second resin film 31 Opening 31a 1st opening 31b 2nd opening 40 Exterior body 40a First exterior sheet 40b Second exterior sheet 50 circuits 60 solder 100,101,102,103,104,105 Secondary battery 111 Electrode lead 112 Insulating material 112a First (upper) insulating member 112b Second (lower) insulating member 120 cases 120a First (upper) case 120b Second (lower) case P Current collector (electrode lead) protruding from the outer casing S board

Claims

1. The battery includes an electrode assembly formed by laminating at least one electrode-constituting layer including a positive electrode, a negative electrode, and a separator, and an exterior body that covers the electrode assembly, a current collector extending from the positive electrode and / or the negative electrode of the electrode assembly protrudes from the exterior body as an electrode lead, an entirety of one main surface of the protruding portion of the current collector protruding from the exterior body is covered with a resin member; At least a portion of the current collector is sandwiched between the resin members inside the exterior body, the resin member comprises two resin films, The two resin films each have an opening, and the electrode assembly is positioned inside the opening.

2. 2. The secondary battery according to claim 1, wherein one main surface of the protrusion of the current collector is entirely covered with one of the two resin films, and at least a portion of the other main surface of the protrusion is covered with the other of the two resin films.

3. The secondary battery according to claim 1 , wherein both surfaces of the protrusion of the current collector are completely covered with the two resin films.

4. The secondary battery according to claim 1 , wherein a total thickness of the current collector and the two resin films is smaller than an overall thickness of the secondary battery.

5. 2. The secondary battery according to claim 1, wherein the resin member comprises a resin having insulating properties and heat-sealing properties.

6. 2. The secondary battery according to claim 1, wherein the resin member comprises a polyolefin resin.

7. The secondary battery according to claim 1 , wherein the two resin films extend inside the exterior body and are bonded to each other.

8. The secondary battery according to claim 1 , wherein at least a portion of each of the two resin films is bonded to the exterior body.

9. 2. The secondary battery according to claim 1, wherein the exterior body is made of a metal plate, a clad material, or a laminate film.

10. The secondary battery according to claim 1 , wherein the exterior body is made of a metal plate or a clad material, and the exterior body is electrically connected to the positive electrode or the negative electrode of the electrode assembly.

Images