JP2024003631A - secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel battery structure from the viewpoint of the electric connection and fixation of an electrode tab and an electrode terminal member.

SOLUTION: There is provided a secondary battery 400 including an electrode assembly 10 and an external body 300 for storing the electrode assembly 10. An electrode tab 6 of the electrode assembly 10 includes a conductive member 20 combined with the electrode tab 6. An electrode terminal member 30 and a conductive terminal member 20 provided in the external body 300 are electrically connected to each other due to the elasticity of at least one of the electrode terminal member 30 and the conductive terminal member 20.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to secondary batteries. In particular, the present invention relates to a secondary battery equipped with an electrode assembly consisting of electrode constituent layers including a positive electrode, a negative electrode, and a separator.

Secondary batteries are so-called storage batteries, so they can be repeatedly charged and discharged, and are used for various purposes. For example, secondary batteries are used in mobile devices such as mobile phones, smartphones, and notebook computers.

Japanese Patent Application Publication No. 2008-66170 JP2017-107688A JP2009-289593A JP2010-27521A Japanese Patent Application Publication No. 2000-260478 JP2009-26490A JP 2020-53333 Publication

A secondary battery needs to be provided with an electrode tab that collects electricity from each electrode component layer of the electrode assembly. On the other hand, in order to use a secondary battery, it is necessary to provide an electrode terminal member for electrical connection with the outside.

In order to use a secondary battery, the electrode tab and the electrode terminal member need to be electrically connected to each other. Further, the electrode tab and the electrode terminal member need to be suitably combined with each other so that the electrical connection is not broken.

The inventors of the present application have diligently investigated whether there is still room for developing a new battery structure with respect to a structure that satisfies both the electrical connection and combination of electrode tabs and electrode terminal members. As a result, it was found that there is still room for development of a structure that satisfies both the electrical connection and fixation of the electrode tab and the electrode terminal member.

The present invention has been made in view of the above problems. That is, the main object of the present invention is to provide a new battery structure from the viewpoint of electrical connection and suitable combination of electrode tabs and electrode terminal members.

The inventor of the present application attempted to solve the above problem by tackling the problem in a new direction rather than by extending the conventional technology. As a result, a secondary battery was invented that achieved the above main objective.

The secondary battery according to the present invention includes:
It comprises an electrode assembly and an exterior body housing the electrode assembly,
the electrode tab of the electrode assembly includes a conductive member associated with the electrode tab;
An electrode terminal member provided on the exterior body and the conductive member are electrically connected to each other due to elasticity of at least one of the electrode terminal member and the conductive member.

In the secondary battery according to the present invention, the electrode tab includes a conductive member combined with the electrode tab, and the electrode terminal member and the conductive member provided on the exterior body are at least one of the electrode terminal member and the conductive member. They are electrically connected to each other due to the elasticity of one of them, and a new battery structure is provided from the viewpoint of electrical connection and suitable combination between the electrode tab and the electrode terminal member. In such a new battery structure, welding is not required for electrical connection between the electrode terminal member and the conductive member, so the welding process can be omitted and a secondary battery can be manufactured more easily.

1A and 1B show schematic cross-sectional views of electrode assemblies (FIG. 1A: unwound flat layered battery, FIG. 1B: wound battery). FIG. 2 shows a schematic partial cross-sectional view of a secondary battery according to an embodiment of the present invention. FIG. 3 shows a schematic perspective view of a conductive member according to an embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing how a conductive member and an electrode tab are pressure-bonded according to an embodiment of the present invention. FIG. 5 shows a schematic perspective view of a conductive member according to an embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing how a conductive member and an electrode tab are pressure-bonded according to an embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing welding of a conductive member and an electrode tab according to an embodiment of the present invention. FIG. 8 shows a schematic partial cross-sectional view of a secondary battery according to an embodiment of the present invention. FIG. 9 shows a schematic cross-sectional view illustrating how the electrode terminal member according to an embodiment of the present invention is integrated with a resin member. FIG. 10 is a schematic cross-sectional view showing how an electrode terminal member according to an embodiment of the present invention is fixed with a rivet. FIG. 11 is a schematic perspective view illustrating a method for manufacturing a secondary battery according to an embodiment of the present invention. FIG. 12 is a schematic cross-sectional view illustrating a method for manufacturing a secondary battery according to an embodiment of the present invention. FIG. 13 is a schematic cross-sectional view illustrating a method for manufacturing a secondary battery according to an embodiment of the present invention. FIG. 14 is a perspective view of a secondary battery according to an embodiment of the present invention. FIG. 15 is a schematic partial cross-sectional view of a conventional secondary battery.

Below, a secondary battery according to one embodiment of the present invention will be described in more detail. Although explanations will be made with reference to drawings as necessary, various elements in the drawings are merely shown schematically and illustratively for understanding the present invention, and the appearance and dimensional ratio may differ from the actual thing. .

The direction of "thickness" described directly or indirectly in this specification is based on the lamination direction of the electrode materials that constitute the secondary battery. For example, in the case of a "secondary battery having a plate-like thickness" such as a flat battery, the direction of "thickness" corresponds to the thickness direction of such a secondary battery.

A "cross-sectional view" described directly or indirectly in this specification is based on a hypothetical cross section of the secondary battery cut along the stacking direction of the electrode assembly or electrode constituent layers that constitute the secondary battery. ing. The direction of "thickness" described directly or indirectly in this specification is based on the stacking direction of the electrode materials constituting the secondary battery, the direction along the winding axis of the wound laminated structure, and the like. In one example, the battery is cut along a plane formed by the thickness direction based on the stacking direction of the electrode layers constituting the secondary battery and the longitudinal direction in which the electrode layers extend in the direction in which the electrode terminal member is located. Based on cross section. To put it simply, it is based on the cross-sectional form of a secondary battery shown in FIG. 2 and the like.

The various numerical ranges mentioned herein are intended to include the lower and upper numerical limits themselves, unless expressly stated otherwise. It should be noted that the term "about" means that it may include variations or differences of several percentages, for example ±10%.

[Basic configuration of secondary battery according to the present invention]
The present invention provides a secondary battery. In this specification, the term "secondary battery" refers to a battery that can be repeatedly charged and discharged. The term "secondary battery" is not overly limited by its name, and may include, for example, electrochemical devices such as "electricity storage devices."

A secondary battery according to the present invention includes an electrode assembly having an electrode structural unit including a positive electrode, a negative electrode, and a separator. An electrode assembly 10 is illustrated in FIGS. 1A and 1B. As shown in the figure, a positive electrode 1 and a negative electrode 2 are stacked with a separator 3 in between to form an electrode structural unit 10. An electrode assembly is formed by stacking at least one such electrode structural unit (see FIG. 1A), or an electrode assembly is formed by winding the electrode structural units (see FIG. 1B). . In a secondary battery, such an electrode assembly is enclosed in an outer case together with an electrolyte (for example, a non-aqueous electrolyte).

The positive electrode includes at least a positive electrode material layer and a positive electrode current collector (for example, a positive electrode current collector in a layered form). In the positive electrode, a positive electrode material layer is provided on at least one side of a positive electrode current collector, and the positive electrode material layer contains a positive electrode active material as an electrode active material. For example, each of the plurality of positive electrodes in the electrode assembly may be provided with a positive electrode material layer on both sides of the positive electrode current collector, or may be provided with a positive electrode material layer only on one side of the positive electrode current collector. . From the viewpoint of further increasing the capacity of the secondary battery, the positive electrode may be provided with positive electrode material layers on both sides of the positive electrode current collector.

The negative electrode includes at least a negative electrode material layer and a negative electrode current collector (for example, a negative electrode current collector in a layered form). In the negative electrode, a negative electrode material layer is provided on at least one side of a negative electrode current collector, and the negative electrode material layer contains a negative electrode active material as an electrode active material. For example, each of the plurality of negative electrodes in the electrode assembly may be provided with a negative electrode material layer on both sides of the negative electrode current collector, or may be provided with a negative electrode material layer only on one side of the negative electrode current collector. . From the viewpoint of further increasing the capacity of the secondary battery, the negative electrode may be provided with negative electrode material layers on both sides of the negative electrode current collector.

The electrode active materials contained in the positive and negative electrodes, that is, the positive and negative electrode active materials, are substances that are directly involved in the transfer of electrons in secondary batteries, and are the main materials of the positive and negative electrodes that are responsible for charging and discharging, that is, battery reactions. be. More specifically, ions are brought into the electrolyte due to "the positive electrode active material contained in the positive electrode material layer" and "the negative electrode active material contained in the negative electrode material layer", and these ions are brought into contact between the positive electrode and the negative electrode. The battery moves and exchanges electrons to perform charging and discharging. The positive electrode material layer and the negative electrode material layer may be layers capable of intercalating and deintercalating lithium ions. In other words, the battery may be a non-aqueous electrolyte secondary battery in which lithium ions move between the positive electrode and the negative electrode via the non-aqueous electrolyte to charge and discharge the battery. When lithium ions are involved in charging and discharging, the secondary battery according to the present invention corresponds to a so-called lithium ion battery, and the positive electrode and the negative electrode have a layer that can insert and release lithium ions.

When the positive electrode active material of the positive electrode material layer is composed of, for example, granules, a binder may be included in the positive electrode material layer for more sufficient contact between the particles and shape retention. Furthermore, a conductive additive may be included in the positive electrode material layer in order to facilitate the transmission of electrons that promote battery reactions. Similarly, when the negative electrode active material of the negative electrode material layer is composed of, for example, granules, a binder may be included for better contact between particles and shape retention, and to facilitate the transfer of electrons that promote battery reactions. A conductive additive may be included in the negative electrode material layer for smooth conduction. As described above, since a plurality of components are contained, the positive electrode material layer and the negative electrode material layer can also be referred to as a "positive electrode composite material layer" and a "negative electrode composite material layer," respectively.

The positive electrode active material may be a material that contributes to intercalation and desorption of lithium ions. From this point of view, 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. That is, in the positive electrode material layer of the secondary battery according to this embodiment, such a lithium transition metal composite oxide may be included as a positive electrode active material. For example, the positive electrode active material is lithium cobalt oxide, lithium nickel oxide, lithium manganate, lithium iron phosphate, or a material in which a part of the transition metal thereof is replaced with another metal. Although such positive electrode active materials may be contained as a single species, they may be contained in a combination of two or more types.

The binder that can be contained in the positive electrode material layer is not particularly limited, but includes polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, and polytetrafluoroethylene. At least one selected from the group consisting of: The conductive additive that can be included in the positive electrode material layer is not particularly limited, but includes carbon blacks such as thermal black, furnace black, channel black, Ketjen black and acetylene black, graphite, carbon nanotubes, and vapor phase growth. Examples include at least one selected from carbon fibers such as carbon fibers, metal powders such as copper, nickel, aluminum and silver, and polyphenylene derivatives.

Although the thickness dimension of the positive electrode material layer is not particularly limited, it 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 material layer is the thickness inside the secondary battery, and the average value of measurements at ten arbitrary locations is used.

The negative electrode active material may be a material that contributes to intercalation and desorption of lithium ions. From this point of view, the negative electrode active material may be, for example, various carbon materials, oxides, lithium alloys, or the like.

Various carbon materials for the negative electrode active material include graphite (eg, natural graphite and/or artificial graphite), hard carbon, soft carbon, and/or diamond-like carbon. Examples of the oxide of the negative electrode active material include at least one selected from the group consisting of silicon oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, and the like. The lithium alloy of the negative electrode active material may be any metal that can be alloyed with lithium, such as Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, It is a binary, ternary or higher alloy of metal such as La and lithium.

The binder included in the negative electrode material layer is not particularly limited, but at least one selected from the group consisting of styrene-butadiene rubber, polyacrylic acid, polyvinylidene fluoride, polyimide resin, and polyamideimide resin. can be mentioned. The conductive additives that can be included in the negative electrode material layer include, but are not particularly limited to, carbon blacks such as thermal black, furnace black, channel black, Ketjen black and acetylene black, graphite, carbon nanotubes, and vapor phase growth. Examples include at least one selected from carbon fibers such as carbon fibers, metal powders such as copper, nickel, aluminum and silver, and polyphenylene derivatives. Note that the negative electrode material layer may contain a component resulting from a thickener component (for example, carboxymethylcellulose) used during battery manufacture.

Although the thickness dimension of the negative electrode material layer is not particularly limited, it 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 material layer is the thickness inside the secondary battery, and the average value of measurements at ten arbitrary locations is used.

A positive electrode current collector and a negative electrode current collector used in a positive electrode and a negative electrode are members that help collect and supply electrons generated in an active material due to a battery reaction. Such a current collector may be a sheet-like metal member and may have a porous or perforated form. For example, the current collector is metal foil, punched metal, mesh, expanded metal, or the like. The positive electrode current collector used in the positive electrode may be made of a metal foil containing at least one member selected from the group consisting of aluminum, stainless steel, nickel, etc., and is, for example, an aluminum foil. On the other hand, the negative electrode current collector used in the negative electrode may be made of a metal foil containing at least one selected from the group consisting of copper, stainless steel, nickel, etc., and is, for example, a copper foil.

The separator is a member provided from the viewpoint of preventing short circuits due to contact between positive and negative electrodes and retaining electrolyte. In other words, the separator can be said to be a member that allows ions to pass through while preventing electronic contact between the positive electrode and the negative electrode. For example, a separator is a porous or microporous insulating member that has a membrane shape due to its small thickness. By way of example only, a microporous membrane made of polyolefin may be used as the separator. In this regard, the microporous membrane used as the separator may contain, for example, only polyethylene (PE) or polypropylene (PP) as the polyolefin. Furthermore, the separator may be a laminate 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.

The thickness of the separator is not particularly limited, but may be 1 μm or more and 100 μm or less, for example, 5 μm or more and 20 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 the measured values at ten arbitrary locations is used.

In the secondary battery according to the present invention, an electrode assembly including a positive electrode, a negative electrode, and a separator is enclosed in an exterior body together with an electrolyte. The electrolyte assists in the movement of metal ions released from the electrodes (positive and negative electrodes). The electrolyte may be a "non-aqueous" electrolyte such as an organic electrolyte and an organic solvent, or it may be an "aqueous" electrolyte containing water. In one exemplary embodiment, the secondary battery according to the present invention is a non-aqueous electrolyte secondary battery in which an electrolyte containing a "non-aqueous" solvent and a solute is used as the electrolyte.

A specific nonaqueous electrolyte solvent may contain at least carbonate. Such carbonates may be cyclic carbonates and/or linear carbonates. Although not particularly limited, examples of the 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). be able to. Examples of chain carbonates include at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), and dipropyl carbonate (DPC). In one exemplary embodiment of the invention, a combination of cyclic carbonates and linear carbonates is used as the non-aqueous electrolyte, such as a mixture of ethylene carbonate and diethyl carbonate. As a specific solute of the non-aqueous electrolyte, for example, Li salt such as LiPF ₆ and/or LiBF ₄ may be used.

As the electrode tab, any electrode tab used in the field of secondary batteries can be used. The electrode tabs may be constructed of any material through which electron transfer can be achieved, and are typically constructed of conductive materials such as silver, gold, copper, iron, tin, platinum, aluminum, nickel, and/or stainless steel. Ru. The shape of the electrode tab is not particularly limited, and may be linear or plate-shaped, for example. The positive and negative electrode tabs (hereinafter also collectively referred to as "positive and negative electrode tabs") may protrude from either side of the electrode assembly. The positive and negative electrode tabs may each protrude from different surfaces of the electrode assembly, or may each protrude from the same surface. From the viewpoint of making the secondary battery compact, the electrode tabs of the positive and negative electrodes may protrude from the same surface. That is, the positive electrode tab and the negative electrode tab may extend so as to protrude from the same end surface (ie, the same side surface) of the electrode assembly.

The exterior body is usually a hard case and may consist of two members, such as a main body and a lid. For example, when the exterior body is composed of a main body part and a lid part, the main body part and the lid part are used to store the electrode assembly, electrolyte, electrode tab, and part or all of the electrode terminal member if desired. , sealed. The method of sealing the exterior body is not particularly limited, and for example,
They may be combined with each other by laser welding to form an exterior body, or may be combined with each other by caulking to form an exterior body. The exterior body may be provided with an injection port for injecting the electrolyte into the exterior body. After injecting the electrolyte, the injection port may be sealed with a resin stopper.

Any material that can be used to construct a hard case type exterior body in the field of secondary batteries can be used as the material for the main body and the lid of the exterior body. Such materials may be conductive materials in which electron transfer can be achieved, or insulating materials in which electron transfer cannot be achieved. The material of the exterior body may be a conductive material from the viewpoint of electrode extraction.

Conductive materials include, for example, conductive materials such as silver, gold, copper, iron, tin, platinum, aluminum, nickel and/or stainless steel. Insulating materials include, for example, insulating polymeric materials such as polyester (eg, polyethylene terephthalate), polyimide, polyamide, polyamideimide, and/or polyolefin (eg, polyethylene and/or polypropylene).

From the above-mentioned viewpoints of conductivity and rigidity, both the main body and the lid may be made of stainless steel. As defined in "JIS G 0203 Steel Terminology," stainless steel is an alloy steel containing chromium or chromium and nickel, and generally has a chromium content of about 10.5% or more of the total. Refers to steel. Such stainless steels include martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, austenitic-ferritic stainless steel, and/or precipitation hardening stainless steel.

The dimensions of the main body and lid of the exterior body are determined mainly depending on the dimensions of the electrode assembly. For example, the exterior body may have dimensions that prevent the electrode assembly from moving within the exterior body when the electrode assembly is housed therein. By preventing the electrode assembly from moving, damage to the electrode assembly due to impact or the like can be prevented and safety of the secondary battery can be improved.

The exterior body may be a flexible case such as a pouch made of a laminate film. The laminate film has a structure in which at least a metal layer (for example, aluminum, etc.) and an adhesive layer (for example, polypropylene and/or polyethylene, etc.) are laminated, and a protective layer (for example, nylon and/or polyamide, etc.) is laminated. ) may be stacked.

The thickness dimension (namely, wall thickness dimension) of the exterior body is not particularly limited, but may be 10 μm or more and 200 μm or less, for example, 50 μm or more and 100 μm or less. The average value of the measured values at ten arbitrary locations is used as the thickness dimension of the exterior body.

[Characteristics of the secondary battery according to the present invention]
The secondary battery according to the present invention is a battery comprising an electrode assembly and an exterior body housing the electrode assembly, and the electrode tab of the electrode assembly and the electrode terminal member provided on the exterior body are electrically connected to each other. It is characterized by the form in which it is connected to.

Specifically, the secondary battery according to the present invention includes a conductive member combined with an electrode tab, and the electrode terminal member and the conductive member provided on the exterior body are connected to the electrode terminal member and the conductive member. They are electrically connected to each other due to the elasticity of at least one of them. That is, since the electrode terminal member and the conductive member are electrically connected to each other due to their elasticity, it is possible to extract electricity from the electrode assembly to the outside.

In this specification, "elasticity" refers to the property of deforming an object by applying an external force and then returning to its original state when the force is removed. In other words, it means the property that when a force is applied to an object to cause it to deform, a force is generated that causes the object to return to its state before the force was applied. In this specification, the "force" is referred to as "elastic force."

FIG. 2 shows a secondary battery 400 according to an embodiment of the present invention. The secondary battery 400 includes an electrode assembly 10 housed inside an exterior body 300. An electrode tab 6 is provided on each of the electrode constituent layers 5 that constitute the electrode assembly 10 . The electrode tab 6 is combined with a conductive member 20. Specifically, the respective electrode tabs 6 provided on each electrode layer are collected and combined with the conductive member 20.

The exterior body 300 is provided with an electrode terminal member 30 for electrical connection with the outside. The electrode terminal member 30 is provided so as to cross between the outside of the exterior body 300 and the inside of the exterior body 300 with the resin member 50 interposed therebetween. Inside the exterior body 300, the electrode terminal member 30 and the conductive member 20 are electrically connected to each other.

In the embodiment shown in FIG. 2, the electrode terminal member 30 is positioned so as to fit into the shape formed by folding back the end portion of the conductive member 20. In such a positional relationship between the electrode terminal member 30 and the conductive member 20, the conductive member 20 and/or the electrode terminal member 30 are receiving an external force from each other, and the conductive member 20 and/or the electrode terminal member 30 A force that resists the external force, that is, an elastic force can act on the object. Due to such elastic force, the conductive member 20 and the electrode terminal member 30 are pressed against each other and come into contact with each other, so that they can be electrically connected. In other words, the electrode terminal member 30 and the conductive member 20 are electrically connected to each other due to the elasticity of at least one of them.

Since the secondary battery according to one embodiment has the above characteristics, it has a structure different from that of conventional secondary batteries. In conventional secondary batteries, the electrode tab and the electrode terminal member are welded together to ensure electrical connection. Conventional secondary battery manufacturing processes require welding, and there is room for improvement in terms of processing costs and secondary battery manufacturing efficiency. In the present invention, since the electrode terminal member and the conductive member are electrically connected to each other due to the elasticity of at least one of the electrode terminal member and the conductive member, electrical connection by welding is not required. Therefore, the manufacturing efficiency of the secondary battery can be improved in that costs related to welding machines, welding materials, and processing can be reduced, and the welding process can be omitted.

Further, in the conventional electrical connection by welding or the like, the electrode tab and the electrode external terminal are firmly fixed so that the electrical connection between the electrode tab and the electrode external terminal is not broken. Therefore, electrical connections made by welding or the like have difficulty absorbing vibrations or shocks from the outside, and the connected portions are likely to be damaged. For example, there is a risk that the welded portion may break due to accumulation of load on the welded portion due to external vibrations or shocks, or stress concentration on the welded portion.

In the present invention, the electrode terminal member and the conductive member are electrically connected to each other due to the elasticity of at least one of the electrode terminal member and the conductive member. can be absorbed effectively. That is, even if an external force is applied to the electrically connected portion due to elasticity due to external vibrations, shocks, etc., the electrical connection can be maintained because the elastic force against the external force acts on the connected portion. Therefore, in the present invention, the electrical connection between the electrode terminal member and the conductive member can be easily maintained even in an environment where vibrations or shocks may be applied.

Note that the conductive member and the electrode terminal member are provided on each of the positive electrode side and the negative electrode side, unless otherwise specified. That is, a positive electrode conductive member and a positive terminal member are provided on the positive electrode side. A negative electrode conductive member and a negative electrode terminal member are provided on the negative electrode side. In this specification, when simply referred to as a conductive member, it means at least one of a positive conductive member and a negative conductive member. Similarly, when simply referring to an electrode terminal member, it means at least one of a positive electrode terminal member and a negative electrode terminal member. The effects of the present invention can also be exerted on each of the positive electrode side and the negative electrode side, unless otherwise specified.

The present invention can further adopt the following aspects.

In one embodiment, the electrode terminal member and the conductive member may be electrically connected to each other due to the elasticity of the conductive member. In other words, the electrode terminal member and the conductive member may be electrically connected to each other by an elastic force that resists an external force applied to the conductive member.

In one embodiment, the conductive member may exhibit elasticity due to its shape. In other words, elastic force resulting from displacement of a three-dimensional shape formed by the conductive member may be utilized. For example, it may utilize elastic force caused by displacement of at least a portion of a three-dimensional shape formed by curving and/or bending a conductive member. In the embodiment shown in FIG. 2, the electrode terminal member 30 inside the exterior body 300 is positioned so as to fit into the shape formed by folding back the outermost end 21 of the conductive member 20. In other words, it can be said that the electrode terminal member 30 is fitted in such a way that the folded shape of the conductive member 20 is pushed out.

While the spread conductive member 20 is receiving an external force, a force that resists the external force, that is, an elastic force may act on the conductive member 20 . Due to such elastic force, the conductive member 20 can act to press against the electrode terminal member 30. That is, since the conductive member 20 exhibits elasticity due to the shape of the conductive member 20, the elastic force of the conductive member 20 is used to electrically connect the conductive member 20 and the electrode terminal member 30 to each other. can be connected to. By adopting such an aspect, the electrical connection between the conductive member 20 and the electrode terminal member 30 can easily become stronger.

As described above, examples of the mode in which the conductive member exhibits elasticity due to the shape of the conductive member include the folded shape of the conductive member. The folded shape may be formed by, for example, curving or bending the conductive member. The folded shape may be formed by curving and/or bending the conductive member multiple times.

As shown in FIG. 2, "curving" in the present disclosure refers to bending in a curved (or arcuate) manner (i.e., bending in a substantially curved manner) in a cross-sectional view, and having a rounded outline. However, it also includes bending. In the present disclosure, "bending" refers to bending at an obtuse or acute angle (that is, bending approximately linearly) in a cross-sectional view, and may have an angular outline (for example, a roughly V-shaped outline).

In one embodiment, the conductive member may include a folded conductive curved portion, and the conductive curved portion may be in contact with the electrode terminal member. As shown in FIG. 2, the conductive member 20 is folded back, and the folded portion has a curved shape. In other words, the folded portion of the folded conductive member 20 becomes the conductive curved portion 22 . Since the shape of the conductive curved portion 22 is continuously displaced, external force applied to the conductive member 20 is easily transmitted to the entire curved portion. In other words, when an external force is applied, the entire curved portion is easily deformed. For example, when an external force is applied, the folded shape tends to open widely, so that the electrode terminal member 30 easily fits into the shape formed by folding back the extreme end 21 of the conductive member 20. Further, the external force applied to the conductive member 20 tends to act on the entire curved portion. Since the external force is more easily dispersed over the entire curved portion, damage to the conductive member 20 due to local fatigue can be more easily suppressed.

In one embodiment, as shown in FIGS. 2 and 3, the conductive member 20 is folded back so that the same main surfaces thereof face each other. In such a folded portion of the conductive member, the outermost end 21 may be curved away from the main surface facing the folded portion of the conductive member. By adopting such an aspect, the insertion opening formed by folding back the most end portion 21 of the conductive member can be made wider. Therefore, the electrode terminal member 30 can be easily fitted into the shape formed by folding back the outermost end 21 of the conductive member, and the electrical connection between the conductive member 20 and the electrode terminal member 30 can be facilitated.

In one embodiment, as shown in FIGS. 2 and 3, the conductive member 20 is folded back so that the same main surfaces thereof face each other. Between the endmost part 21 of the conductive member and the conductive curved part 22, there may be a part that curves convexly toward the main surface facing the folded part of the conductive member. By adopting such an aspect, the convexly curved portion can function as a retainer for the electrode terminal member 30 that fits into the shape formed by the conductive member. Therefore, the electrical connection between the conductive member and the electrode terminal member becomes more difficult to break.

In one embodiment, the electrode tab and the conductive member may be combined with each other such that the electrode tab passes through an opening provided in the conductive member. The opening provided in the electrically conductive member may be provided by subjecting a portion of the electrically conductive member to shearing. For example, a part of the conductive member may be removed. That is, a portion of the conductive member may be hollowed out to provide a through hole.

When providing an opening in the conductive member by removing a part of the conductive member, the opening may be provided at a location where the conductive member and the electrode terminal member are electrically connected to each other, for example. In the embodiment shown in FIGS. 2 and 3, the conductive curved portion 22 of the conductive member is provided with a first opening 25 formed by removing a portion of the conductive member 20. In the embodiment shown in FIGS. In other words, the first opening 25 is provided at the location where the conductive member 20 and the electrode terminal member 30 are electrically connected, and the electrode tab 6 is inserted through the first opening 25. .

By passing through the first opening 25 of the conductive member 20, the electrode tab 6 is easily interposed between the conductive member 20 and the electrode terminal member 30, and the electrode tab, the conductive member, and the electrode terminal member It becomes easier to integrate them with each other. In other words, since the electrode tab 6 can be held between the conductive member 20 and the electrode terminal member 30, the electrode tab 6 can be more easily fixed. As described above, in the present invention, the electrode tab 6 and the conductive member 20 can be combined with each other without using welding to establish a suitable electrical connection.

In another embodiment, a slit may be provided in the conductive member and the slit may be expanded to form an opening. That is, an opening may be provided in the conductive member by pressing and deforming the conductive member with a cut, and expanding the cut. Since the opening formed by this method is formed by being forced wide, the opening can be closed again by applying an external force.

A plurality of slits may be provided in the conductive member. A tunnel-shaped opening may be formed in the conductive member by providing a slit. Specifically, by pressing between the plurality of slits provided in the conductive member, the conductive member between the plurality of slits may be deformed so as to protrude, thereby forming an opening. In the case of this method, openings corresponding to the number of slits provided are formed.

For example, when two slits are used to form an opening, two openings 26 may be formed from each slit, as shown in FIG. Since the respective openings 26 are positioned so as to be lined up on the same plane, for example, as shown in FIG. It can be inserted. In having such a pair of openings 26, it can be said that the conductive member shown in FIG. 3 is provided with a tunnel portion 27 having two second openings.

In one embodiment, the electrode tab and the electrically conductive member may be assembled together by pressure bonding. “Pressure bonding” means pressing and joining together. Specifically, "pressure bonding" refers to a mode in which they are in close contact with each other under pressure and/or shear force, rather than simply in contact with each other.

The pressure bonding between the electrode tab and the conductive member may be achieved by inserting the electrode tab into a second opening provided in the conductive member and closing the second opening together with the electrode tab. As described above, since the second opening is formed by being pushed apart, the opening can be closed again by applying an external force. By closing the second opening with the electrode tab inserted through the second opening, the electrode tab can be held between the open ends of the second opening and pressure-bonded to the conductive member.

As shown in FIG. 3, when a tunnel portion 27 is formed by providing a second opening in the conductive member, pressing the tunnel portion 27 crushes the second opening 26 together with the electrode tab 6. Good too. According to this aspect, the electrode tab 6 and the conductive member 20 are pressure-bonded and can be easily fixed firmly. As described above, in the present invention, the electrode tab 6 and the conductive member 20 can be combined with each other without using welding to establish a suitable electrical connection.

In one embodiment, the conductive member may be provided with a divided tunnel portion. In other words, a plurality of tunnel portions may be provided in the conductive member. For example, as shown in FIG. 5, two tunnel portions 27 may be provided in the conductive member 20. When providing a plurality of tunnel portions in the conductive member, as shown in FIG. 5, a plurality of tunnel portions having the same shape may be provided, or a plurality of tunnel portions having different shapes may be provided.

When the conductive member is provided with divided tunnel portions, each tunnel portion can be relatively small. Specifically, in the conductive member 20 in the embodiment of FIG. 5, the tunnel portion 27 is provided by being divided into two, whereas the size of each tunnel portion is different from that in the embodiment of FIG. The tunnel portion 27 is smaller than the tunnel portion 27.

When the conductive member is provided with divided tunnel portions, the size of each tunnel portion may be relatively small, and in particular, the width of each tunnel portion may be relatively short. “Width of the tunnel portion” means the length of the tunnel portion in the arrangement direction of the two second openings that the tunnel portion has. Comparing FIG. 3 with FIG. 5, the width of each tunnel section 27 in the embodiment of FIG. 5 is shorter than the width of the tunnel section of FIG. 3. As the width of the tunnel portion becomes shorter, it becomes easier to press and crush the tunnel portion. In other words, since the width of the tunnel portion is shortened, the stress for crushing the tunnel portion tends to be relatively small. Therefore, by separately providing the tunnel portion 27 in the conductive member 20, it becomes easier to pressure-join the electrode tab 6 to the conductive member 20 with a smaller pressing force. Further, since the electrode tab 6 and the conductive member 20 are pressure-bonded by the plurality of tunnel portions (second openings), the bonding reliability can be further improved.

The opening may be crushed along with the electrode tab by, for example, pressing the tunnel portion 27 with a punch 600 or the like to plastically deform it, as shown in FIGS. 4 and 6. In this method, the electrode tab 6 inserted through the tunnel portion 27 is pressure-bonded by the plastically deformed tunnel portion 27.

In order to strengthen the bond between the electrode tab and the conductive member, the conductive member and the electrode tab in the tunnel portion may be joined by welding while the conductive member is inserted through the tunnel portion. The conductive member and the electrode tab may be welded by, for example, resistance welding, ultrasonic welding, laser welding, or the like. When welding is performed with the electrode tab inserted into the tunnel portion, the conductive member and the electrode tab may be welded together by resistance welding in order to further strengthen the bond between the electrode tab and the conductive member. In resistance welding, as shown in FIG. 7, the electrode tab 6 and the conductive member 20 are held between one resistance welding rod 610 and the other resistance welding rod 620, and the electrode tab 6 and the conductive member 20 are held together. It can fit more closely. Since the welding is performed in a more intimate state, the reliability of the bond between the electrode tab 6 and the conductive member 20 is improved, and the welding between the electrode tab 6 and the conductive member 20 can be made stronger.

The first opening and the second opening may be provided on the conductive member by machining, for example. As for machining, openings may be provided by cutting, perforating, punching, etc. the conductive member by shearing.

In one embodiment, the electrode terminal member may exhibit elasticity due to the terminal shape located inside the sheath. In other words, the elastic force generated when the three-dimensional shape of the electrode terminal member is displaced may be used. For example, it may utilize elastic force generated when at least a portion of a three-dimensional shape formed by curving and/or bending the electrode terminal member is displaced. In the embodiment shown in FIG. 2, the shape formed by folding back the extreme end 31 of the electrode terminal member 30 is positioned so as to fit into the space formed by folding back the conductive member 20. In other words, the folded shape of the electrode terminal member 30 can be compressed and deformed by the conductive member 20. An elastic force may act on the folded shape of the deformed electrode terminal member 30 to return it to its original shape.

Due to the elastic force, the electrode terminal member 30 can act to press against the conductive member 20. In other words, since the electrode terminal member 30 exhibits elasticity due to the shape of the electrode terminal member 30, the elastic force of the electrode terminal member 30 is used to electrically connect the conductive member 20 and the electrode terminal member 30 to each other. can be connected to. By adopting such an aspect, the electrical connection between the conductive member 20 and the electrode terminal member 30 can easily become stronger.

In one embodiment, the electrode terminal member may include a folded terminal curved portion, and the terminal curved portion may be in contact with the conductive member. As shown in FIG. 2, the electrode terminal member 30 is folded back, and the folded portion has a curved shape. In other words, the folded portion of the electrode terminal member 30 becomes the terminal curved portion 32 . The curved shape makes it easier for the electrode terminal member 30 and the conductive member 20 to come into contact when the electrode terminal member 30 is fitted into the shape formed by the conductive member 20 . In other words, since the terminal curved portion 32 of the electrode terminal member 30 has a rounded shape, the portion in contact with the conductive member 20 is less likely to be biased. Therefore, the electrical connection between the electrode terminal member 30 and the conductive member 20 can be easily maintained. Further, the external force applied to the electrode terminal member 30 tends to act on the entire curved portion. Since the external force is more easily dispersed over the entire curved portion, damage to the electrode terminal member 30 due to local fatigue can be more easily suppressed.

In one embodiment, the conductive member includes a folded conductive curved section, the electrode terminal member includes a folded terminal curved section, and the terminal curved section is positioned inside the conductive curved section to provide an electrode. The terminal member and the conductive member may be connected to each other. "Inside the conductive curved part" means the space 24 side surrounded by the main surface, the curved part, and the extreme end of the folded conductive member, as shown in FIGS. 2 and 3. A terminal curved portion 32 is positioned in the space 24 .

Focusing on the conductive member 20 in the embodiment shown in FIG. 2, the electrode terminal member 30 is positioned so as to fit into the shape formed by folding back the outermost end 21 of the conductive member 20. In other words, it can be said that the electrode terminal member 30 is fitted in such a way that the folded shape of the conductive member 20 is pushed out. An elastic force may act on the folded shape of the conductive member 20 that has been stretched out to return it to its original shape.

On the other hand, focusing on the electrode terminal member 30, the shape formed by folding back the extreme end 31 of the electrode terminal member 30 is positioned so as to fit into the space 24 formed by folding back the conductive member 20. . In other words, it can be said that the folded shape of the conductive member 20 compresses the electrode terminal member 30. An elastic force may act on the folded shape of the compressed electrode terminal member 30 to return it to its original shape.

In the above aspect, the elastic force from the conductive member can act on the electrode terminal member, and the elastic force from the electrode terminal member can act on the conductive member. That is, elastic forces from both can act on the electrode terminal member and the conductive member. In other words, the electrode terminal member and the conductive member provided in the exterior body are electrically connected to each other due to the elasticity of both the electrode terminal member and the conductive member. By adopting such an aspect, the electrical connection between the electrode terminal member and the conductive member can be made stronger. In addition, in that the elastic force from both the electrode terminal member and the conductive member acts, it can be said that the conductive curved portion and the terminal curved portion compensate for the stress for electrical connection with each other with their respective elastic forces. . In this regard, the conductive curved portion and the terminal curved portion may engage each other in a complementary manner.

The conductive curved portion 22 and the terminal curved portion 32 that engage each other in a complementary manner may have a configuration as shown in FIG. 2 . Specifically, in the illustrated cross-sectional view, the inner contour of the conductive curved portion 22 and the outer contour of the terminal curved portion 32 may be in contact with each other. That is, the inner contour of the conductive curved portion 22 and the outer contour of the terminal curved portion 32 may have a mutually complementary relationship. By adopting such an aspect, the electrical connection between the conductive member 20 and the electrode terminal member 30 can be more suitably and easily strengthened.

In one embodiment, the connection between the conductive member and the electrode terminal member may be a non-welded connection that does not include a weld. In other words, the conductive member and the electrode terminal member may be electrically connected and fixed to each other without forming a welded portion. This aspect is achieved by the electrode terminal member and the conductive member provided in the above-mentioned exterior body being electrically connected to each other due to the elasticity of at least one of the electrode terminal member and the conductive member. . In this respect, the manufacturing efficiency of the secondary battery can be improved in that the costs related to welding machines, welding materials, and processing can be reduced, and the welding process can be omitted. Further, in this embodiment, since the connection is a non-welded connection that does not include a welded portion, a reversible connection form can be achieved. That is, after the connection between the conductive member and the electrode terminal member is established, the connection between the conductive member and the electrode terminal member can be released.

In one embodiment, the connection between the conductive member and the electrode tab is a non-welded connection that does not include a weld. In other words, the conductive member and the electrode tab may be electrically connected and fixed to each other without forming a welded portion. This aspect is achieved by providing an electrode tab between the conductive member and the electrode terminal member, as shown in FIG. As described above, the electrode terminal member and the conductive member are electrically connected to each other due to the elasticity of at least one of the electrode terminal member and the conductive member. An elastic force can be applied to such electrically connected portions. Since the elastic force can press the electrode tab against the conductive member, the electrode tab can be pressed and bonded to the conductive member. A non-welded connection between the conductive member and the electrode tab that does not include a weld is, for example, by providing a tunnel portion having a second opening in the conductive member, inserting the electrode tab therein, and opening the tunnel portion. This can also be done by crimping the electrode tab together. By making a non-welded connection that does not include a welded part, a part 700' required for welding in a conventional secondary battery 400' as shown in FIG. 15 can be omitted, and the space can be reduced by that amount. Therefore, the volume of the secondary battery can be reduced and the battery capacity can be easily increased.

Each member included in a secondary battery according to an embodiment of the present invention will be explained below.

<Conductive member>
The positive electrode conductive member may be made of any material that can achieve electron transfer. For example, the positive conductive member may be made of a conductive material, specifically conductive materials such as silver, gold, copper, iron, tin, platinum, aluminum, nickel, and/or stainless steel. configured.

In a preferred embodiment, the positive electrode conductive member and the positive electrode tab may be made of the same metal material. For example, when the positive electrode tab is made of aluminum, the positive electrode conductive member may also be made of aluminum. By adopting such a configuration, the connection stability between the positive electrode conductive member and the positive electrode tab can be easily increased.

The negative electrode conductive member may be made of any material that can achieve electron movement. For example, the negative electrode conductive member may be made of a conductive material, specifically, silver, gold, copper, iron, tin, platinum, aluminum, nickel, and/or stainless steel. be done.

In a preferred embodiment, the negative electrode conductive member and the negative electrode tab may be made of the same metal material. For example, when the negative electrode tab is made of copper, the negative electrode conductive member may also be made of copper. By adopting such a configuration, the connection stability between the negative electrode conductive member and the negative electrode tab can be easily increased. Note that also when nickel or stainless steel is used as the negative electrode tab and the negative electrode conductive member, the connection stability between the negative electrode conductive member and the negative electrode tab tends to be high.

The conductive member can be obtained by subjecting a conductive material to mechanical processing. The mechanical processing may be, for example, a combination of shearing, bending, punching, drilling, and the like. From the viewpoint of efficiently producing a conductive member, the conductive member may be produced by press working. Pressing may be, for example, progressive processing, transfer processing, or single-shot processing. When progressive processing is selected as press processing, a plurality of mechanical processes can be performed continuously, making it easier to manufacture the conductive member at low cost. When subjecting the electrically conductive material to mechanical processing, the electrically conductive material may be in the form of a plate or sheet (for example a blank).

<Electrode terminal member>
The positive electrode terminal member may be made of any material that can achieve electron transfer. For example, the positive terminal member is constructed from a conductive material such as silver, gold, copper, iron, tin, platinum, aluminum, nickel and/or stainless steel.

In a preferred embodiment, the positive terminal member may be made of the same metal material as the positive tab and/or the positive conductive member. For example, when the positive electrode tab and the positive conductive member are made of aluminum, the positive terminal member may also be made of aluminum. By adopting such a configuration, the connection stability between the conductive member and the current collecting electrode terminal member is likely to be increased.

For example, the positive terminal member may be corroded by the external environment. In particular, the positive electrode terminal member exposed to the outside of the exterior body is easily exposed to the external environment and is relatively easily corroded. For example, when a positive electrode terminal member is oxidized, it becomes difficult to make an electrical connection at the oxidized portion, and a connection failure may occur.

From the viewpoint of suppressing corrosion of the positive electrode terminal member, the positive electrode terminal member may be made of a clad material. The cladding material may be made of a combination of two or more metals selected from the group consisting of silver, gold, copper, iron, tin, platinum, aluminum, nickel, and stainless steel, for example. Note that the cladding material used for the positive electrode terminal member may be selected depending on, for example, the conductive material used for the positive electrode tab and/or the positive electrode conductive member. In a preferred embodiment, when aluminum is used as the positive electrode conductive member, an aluminum-nickel cladding material may be used for the positive electrode terminal member.

When using a cladding material as the positive electrode terminal member, it is preferable that the portion where the positive electrode terminal member and the positive electrode tab are electrically connected be made of the same type of metal. In other words, the portion where the positive electrode terminal member and the positive electrode tab are electrically connected is preferably not connected by different metals. FIG. 8 shows an embodiment in which a cladding material is used as the positive electrode terminal member. As shown in FIG. 8, the positive electrode terminal member is made of two different metals and is a clad material. The surfaces where the positive electrode terminal member and the positive electrode tab come into contact with each other are electrically connected to each other so that they are made of the same type of metal.

The positive electrode terminal member outside the exterior body may have a bent shape, as shown in FIG. 8 . In other words, the end portion of the positive electrode terminal member may be folded back by 180 degrees, and the main surfaces of the positive electrode terminal member made of the same metal may be in contact with each other. The main surface of the cladding material exposed to the outside of the exterior body is preferably a main surface made of a metal with a low ionization tendency among the metals used in the cladding material. By adopting such an aspect, the cladding material can be electrically connected to metals of the same type, and the metal layer exposed to the outside can be made into a main surface made of a metal with a low ionization tendency. This makes it easier to suppress corrosion of the positive electrode terminal member.

The negative electrode terminal member may be made of any material that can achieve electron transfer. For example, the negative terminal member is constructed from a conductive material such as silver, gold, copper, iron, tin, platinum, aluminum, nickel and/or stainless steel.

In a preferred embodiment, the negative terminal member may be made of the same metal material as the negative tab and/or the negative conductive member. For example, when the negative electrode tab and the negative electrode conductive member are made of copper, the negative electrode terminal member may also be made of copper. By adopting such a configuration, the connection stability between the negative electrode conductive member and the negative electrode terminal member is likely to be increased. Note that when nickel or stainless steel is used for the negative electrode tab, the negative electrode conductive member, and the negative electrode terminal member, the connection stability between the negative electrode conductive member and the negative electrode terminal member tends to be high.

<Resin member>
In one embodiment, the electrode terminal member may be fixed to the exterior body using a resin member. For example, the electrode terminal member may be fixed to the exterior body using a single resin member, or may be fixed to the exterior body by combining a plurality of resin members.

(A mode using a single resin member)
A "single resin member" in the present invention means that the resin member is composed of only one resin component. Or, it means that it is not constructed by combining multiple resin parts. In the example shown in FIG. 2, the resin member 50 is composed of one resin component and does not have a structure or a boundary portion that can be separated into a plurality of resin components.

As for the method of fixing the electrode terminal member to the exterior body using a single resin member, for example, the electrode terminal member may be inserted into the exterior body and then the resin may be incorporated and fixed therein. The resin may be incorporated, for example, by injecting a molten resin and then curing the resin into a desired shape. Specifically, the electrode terminal member may be fixed to the exterior body using a resin member by outsert molding.

Outsert molding is a method in which metal parts and the like are set in a mold, and then resin is injection molded to produce a molded product. A molded product produced by outsert molding is, for example, formed by molding a member such as resin around a member such as metal, and covering part or all of the member such as metal with the member such as resin. It's fine. That is, the outsert molded product may have a structure in which a member such as metal and a member such as resin are integrated.

Outsert molding can be performed, for example, by the following method. As shown in FIG. 9A, an exterior member 310 having an opening 320 on its side surface is set in a resin molding die (not shown), and the electrode terminal member 30 is inserted into the opening 320 of the exterior member. In order to prevent short circuits, the electrode terminal member and the exterior case are positioned so that they do not come into contact with each other. In the positioned state, resin injection molding is performed to fix the exterior member and the electrode terminal member with the resin (FIG. 9(b)). An unnecessary portion of the electrode terminal member 30 may be cut (FIG. 9(c)). After fixing the electrode terminal member, the electrode terminal member is bent toward the resin (FIGS. 9(d) and 9(e). Through the above, a molded product in which the exterior member, the electrode terminal member, and the resin are integrated is obtained. .

In the method of fixing the electrode terminal member to the exterior body using a single resin member, the number of parts used for fixing the electrode terminal member to the exterior body tends to be relatively small. Furthermore, when fewer parts are used, the number of assembly steps tends to be reduced. Therefore, the above method can facilitate cost reduction and improve manufacturing efficiency. Furthermore, since the electrode assembly is not fixed by welding, spatter and the like do not occur, reducing the risk of foreign matter getting into the electrode assembly, and making it easier to prevent problems from occurring in the secondary battery. Malfunctions of welding machines (for example, abnormal discharge of resistance welding machines) can also be avoided.

From the viewpoint of improving workability, in outsert molding, an electrode terminal member on the positive electrode side and an electrode terminal member on the negative electrode side may be connected in advance with a metal plate or the like. It becomes easier to adjust the insertion positions of the electrode terminal member on the positive electrode side and the electrode terminal member on the negative electrode side, and it becomes easier to realize more accurate positioning. Note that it is preferable to cut and remove the metal plate or the like used for connection after fixing the exterior member and the electrode terminal member with resin.

(Mode using multiple resin members)
The method of fixing the electrode terminal member to the exterior body using a plurality of resin members may be, for example, a method of fixing the electrode terminal member to the exterior body by crimping the plurality of resin members together. For example, a method may be used in which a rivet part is provided and the rivet part is crimped to clamp and press the exterior body between a plurality of gaskets and fix the exterior body.

The rivet portion is not particularly limited, but may be inserted into, for example, a through hole provided in the exterior body. The rivet portion may be electrically conductive. The gasket may include an outer gasket provided on the outside of the outer case and an inner gasket provided on the inside of the outer case for preventing electrolyte leakage while ensuring electrical insulation between the rivet part and the outer case.

In the embodiment shown in FIG. 10, an electrode terminal member 30 and an inner gasket 51 are provided on the inside of the exterior body, and an outer gasket 52 is provided on the outside of the exterior body. The rivet portion 60 is inserted through openings provided in each of the inner gasket 51, the exterior member 310, and the outer gasket 52. The rivet portion 60 is plastically deformed by crimping and is crimped to sandwich the inner gasket 51 and the outer gasket 52. The electrode terminal member 30 is crimped to the exterior body together with the inner gasket 51 by the rivet portion 60, and electricity can be extracted to the outside from the electrode terminal 70 provided on the outside of the exterior body via the rivet portion 60. There is.

The rivet portion may be made of any material that can achieve electron transfer. For example, the rivet portion is constructed from a conductive material such as silver, gold, copper, iron, tin, platinum, aluminum, nickel and/or stainless steel.

The resin member may be made of an insulating material. For example, the resin member may be made of epoxy resin, polyphenylene sulfide, liquid crystal polymer, aromatic polyester (e.g. polyethylene naphthalate), aromatic polyether ketone, polyester (e.g. polyethylene terephthalate), polyimide, polyamide, polyamideimide, and/or polyolefin. (e.g., polyethylene and/or polypropylene). Note that the resin member may be referred to as a gasket because it is provided to suppress movement of fluid between the inside of the exterior body and the outside of the exterior body. From the viewpoint of further improving the sealing performance of the gasket, the resin material may be epoxy resin, polyphenylene sulfide, or the like.

The resin member may contain filler. As the filler, for example, an inorganic filler and/or an organic filler may be used. The inorganic filler may include at least one selected from the group consisting of metal powder, carbon material, silicon oxide, metal oxide, metal hydroxide, metal nitride, and metal sulfate. For example, ceramic particles, alumina particles, carbon black, graphite, or silica particles may be used as the inorganic filler. The organic filler may include ABS resin, polyamide resin, etherimide resin, polyphenylene sulfide resin, cellulose, and/or phenol resin.

The shape of the inorganic filler and/or organic filler is not particularly limited, and may be granular, spherical, acicular, plate-like, fibrous, and/or amorphous. Note that from the viewpoint of further improving the sealing performance of the gasket, silica particles or the like may be used as the filler.

From the viewpoint of improving the adhesion between the resin member and the exterior member and/or the electrode terminal member, the exterior member and/or the electrode terminal member may be surface treated (or surface modified). Such surface treatment may be, for example, mechanical treatment, priming, chemical treatment, cleaning or electrochemical treatment.

As the mechanical treatment, foreign matter on the surface may be removed using abrasive paper or sandblasting, and fine irregularities may be provided on the surface. Thereby, the contact area between the resin member and the exterior member and/or the electrode terminal member increases, and the adhesion can be further improved. As the primer treatment, the surface may be treated by applying a primer containing one or more selected from the group consisting of polyacrylic resin, urethane resin, epoxy resin, polyamide resin, and silane coupling agent.

[Method for manufacturing a secondary battery of the present invention]
The secondary battery of the present invention can be obtained by enclosing an electrode assembly in which electrode constituent layers including a positive electrode, a negative electrode, and a separator are laminated in an exterior body. Specifically, when enclosing the electrode assembly in the exterior body, a conductive member provided in the electrode assembly and an electrode terminal member provided in the exterior body are connected to at least one of the electrode terminal member and the conductive member. The secondary battery of the present invention can be obtained by electrically connecting them to each other due to the elasticity of one of them.

The electrode assembly may be fabricated using conventional techniques. In providing the conductive member to the electrode assembly, first, the electrode tabs drawn out from each electrode layer of the electrode assembly may be bundled into one assembly. The bundled electrode tabs may be formed into a shape that is easy to attach to a conductive member. For example, the bundled electrode tabs may be compressed to make them thinner. Alternatively, the periphery of the bundled electrode tabs may be cut off to form a rectangular electrode tab.

When attaching the conductive member to the electrode tab, the electrode tab may be provided between the conductive member and the electrode terminal member. By positioning the electrode tab between the conductive member and the electrode terminal member, the electrode tab can be easily fixed. In a preferred embodiment, the fixation may be achieved due to the elasticity of at least one of the electrode terminal member and the conductive member. Further, as shown in FIG. 11(a), when the electrode tab 6 is passed through the first opening 25 provided in the conductive member 20, the electrode tab 6 is positioned between the conductive member 20 and the electrode terminal member. It becomes easier. Further, the electrode tab 6 may be inserted into the second opening 26 of the tunnel portion 27 formed by expanding a slit provided in the conductive member 20. As shown in FIG. 11(b), after insertion, the tunnel portion 27 may be pressed together with the electrode tab 6, and the electrode tab 6 may be crimped onto the conductive member 20. After attaching the conductive member to the electrode tab 6, the electrode tab 6 may be bent so that the conductive member 20 follows the end surface of the electrode assembly 10, as shown in FIG. By bending and positioning the electrode tabs 6 in this manner, it becomes easier to design the secondary battery to save space.

When attaching the electrode terminal member to the exterior body, the electrode terminal member may be fixed to the exterior body with a resin member. For example, the electrode terminal member may be fixed to the exterior body using a single resin member, or may be fixed to the exterior body by combining a plurality of resin members. For example, molten resin may be injected and then cured into a desired shape. Specifically, the electrode terminal member may be fixed to the exterior body using a resin member by outsert molding.

The conductive member provided on the electrode tab and the electrode terminal member provided inside the exterior body may be electrically connected to each other by the method described below.

First, as shown in FIG. 13(a), the conductive member 20 provided on the electrode tab 6 and the electrode terminal member 30 provided inside the exterior body 300 are aligned. Next, as shown in FIG. 13(b), the conductive member 20 is moved toward the electrode terminal member 30, and the conductive member 20 and the electrode terminal member 30 are brought into contact with each other. Specifically, the most end portion 21 of the conductive member 20 and the terminal curved portion of the electrode terminal member 30 are brought into contact with each other.

In one embodiment, when the conductive member 20 is continuously moved toward the electrode terminal member 30 after the contact, as shown in FIG. It is pushed apart from the electrode assembly 10 side by the terminal member 30 . The electrode terminal member 30 is housed in the space 24 formed by the main surface of the conductive member, the conductive curved portion, and the edge portion of the conductive member while the outermost end 21 of the conductive member 20 is being pushed out. Ru. In this state, when an external force is applied to the conductive member 20 by the electrode terminal member 30, a force that resists the external force, that is, an elastic force is generated in the conductive member 20. Due to the elastic force, the conductive member 20 applies an external force to press the electrode terminal member 30.

In one embodiment, as the conductive member 20 continues to move toward the electrode terminal member 30 after contact, the main surface of the conductive member, the conductive curved portion, and the extreme end of the conductive member The electrode terminal member 30 is housed in the space 24 formed. The housed electrode terminal member 30 is subjected to an external force by the conductive member 20 forming the space 24, and is compressed, for example. In such a state, when an external force is applied to the electrode terminal member 30 by the conductive member 20, a force that resists the external force, that is, an elastic force is generated in the electrode terminal member 30. Due to the elastic force, the electrode terminal member 30 applies an external force to press the conductive member 20.

When the electrode terminal member 30 continues to move toward the conductive member 20, the electrode terminal member 30 finally reaches the main surface of the conductive member 20 and the conductive curved portion, as shown in FIG. 13(d). It is positioned in a space 29 surrounded by the end portions. Specifically, the electrode terminal member 30 and the main surface, the curved portion, and the extreme end of the conductive member 20 may come into contact with each other. Here, since the conductive member 20 can be spread apart by the electrode terminal member 30, an elastic force can act toward the electrode terminal member 30. On the other hand, since the electrode terminal member 30 can be compressed by the conductive member 20, an elastic force can act toward the conductive member 20. Therefore, since the conductive member 20 and the electrode terminal member 30 can receive elastic force from at least one of them, the conductive member 20 and the electrode terminal member 30 can come into contact with each other and be electrically connected. In other words, the electrode terminal member 30 and the conductive member 20 provided in the exterior body are electrically connected to each other due to the elasticity of at least one of the electrode terminal member 30 and the conductive member 20.

After the electrode terminal member and the conductive member are electrically connected to each other, the exterior body is sealed by laser irradiation or the like, and an electrolytic solution is injected into the exterior body from an injection port provided in the exterior body. Through the above steps, a secondary battery as illustrated in FIG. 14 is obtained. Note that the electrolyte injection port is plugged with a resin plug 80 or the like.

Although the embodiments of the present invention have been described above, these are merely typical examples. Therefore, those skilled in the art will readily understand that the present invention is not limited thereto and that various embodiments are possible.

The secondary battery according to the present invention can be used in various fields where power storage is expected. Although this is just an example, the secondary battery of the present invention can be used in the electrical, information, and communication fields where electrical and electronic devices are used (e.g., mobile phones, smartphones, notebook computers, digital cameras, activity meters, arm computers, etc.). , electronic paper, wearable devices, RFID tags, card-type electronic money, small electronic devices such as smart watches, and mobile device fields), household and small industrial applications (e.g., power tools, golf carts, household/nursing care/industrial robots), large industrial applications (e.g., forklifts, elevators, harbor cranes), transportation systems (e.g., hybrid vehicles, electric vehicles, buses, trains, electric assist) Bicycles, electric motorcycles, etc.), power system applications (e.g., various power generation, road conditioners, smart grids, home-installed power storage systems, etc.), medical applications (medical equipment such as earphones and hearing aids), and pharmaceutical applications. (fields such as medication management systems), as well as IoT fields, space/deep sea applications (e.g.

1 Positive electrode 2 Negative electrode 3 Separator 5 Electrode constituent layer 6 Electrode tab 10, 10' Electrode assembly 20 Conductive member 21 End portion 22 Conductive curved portion 24 Space surrounded by the main surface, curved portion, and end of the conductive member 25 First opening 26 Second opening 27 Tunnel portion 30 Electrode terminal member 31 End portion 32 Terminal curved portion 50 Resin member 51 Inner gasket 52 Outer gasket 60 Rivet portion 70 Electrode terminal 80 Resin plug 300 Exterior body 310 Exterior member 320 Opening 400, 400' Secondary battery 600 Punch 610 One resistance welding rod 620 Other resistance welding rod 700' Part to be welded

Claims (13)

It comprises an electrode assembly and an exterior body housing the electrode assembly,
an electrode tab of the electrode assembly includes a conductive member associated with the electrode tab;
A secondary battery, wherein an electrode terminal member provided on the exterior body and the conductive member are electrically connected to each other due to elasticity of at least one of the electrode terminal member and the conductive member. The secondary battery according to claim 1, wherein the conductive member exhibits the elasticity due to the shape of the conductive member. The secondary battery according to claim 1, wherein the conductive member includes a folded conductive curved portion, and the conductive curved portion is in contact with the electrode terminal member. The secondary battery according to claim 1, wherein the electrode tab and the conductive member are combined with each other so that the electrode tab passes through an opening provided in the conductive member. The secondary battery according to claim 4, wherein the electrode tab and the conductive member are combined with each other by pressure bonding. The secondary battery according to claim 1, wherein the electrode terminal member exhibits the elasticity due to a terminal shape located inside the exterior body. The secondary battery according to claim 1, wherein the electrode terminal member includes a folded terminal curved portion, and the terminal curved portion is in contact with the conductive member. The secondary battery according to claim 1, wherein the electrode terminal member is fixed to the exterior body with a resin member. The secondary battery according to claim 1, wherein the connection between the conductive member and the electrode terminal member is a non-welded connection that does not include a welded portion. The secondary battery according to claim 1, wherein the combination of the electrode tab and the conductive member is a non-welded combination that does not include a welded part. The conductive member includes a folded conductive curved portion, and the electrode terminal member includes a folded terminal curved portion,
The secondary battery according to claim 1, wherein the terminal curved portion is positioned inside the conductive curved portion and the electrode terminal member and the conductive member are connected to each other. The secondary battery according to claim 11, wherein the conductive curved portion and the terminal curved portion engage each other in a complementary manner in a cross-sectional view. The secondary battery according to any one of claims 1 to 12, wherein the electrodes of the electrode assembly include a positive electrode and a negative electrode capable of intercalating and deintercalating lithium ions.

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