JP2020173890A - Assembled battery and manufacturing method thereof - Google Patents

Abstract

To provide an assembled battery capable of suitably suppressing variations in battery reaction.SOLUTION: An assembled battery according to an embodiment of the present invention includes a unit secondary battery laminate in which a plurality of unit secondary batteries are stacked, and a tightening member that tightens the unit secondary battery laminate, and in a plan view, the tightening member extends from one side of the unit secondary battery in which an external terminal is arranged to the other side facing the one side.SELECTED DRAWING: Figure 1

Description

The present invention relates to an assembled battery and a method for manufacturing the assembled battery.

The assembled battery 400'has been used as a drive power source for electric motorcycles, electric bicycles, electric vehicles, and the like. The assembled battery 400'includes a unit secondary battery laminate 200' obtained by stacking a plurality of unit secondary batteries 100'that can be repeatedly charged and discharged along one direction (see Patent Document 1). .. The unit secondary battery 100'consists of at least a positive electrode, a negative electrode, and a separator between them. The positive electrode includes a positive electrode material layer and a positive electrode current collector, and the negative electrode includes a negative electrode material layer and a negative electrode current collector. Further, from the viewpoint of alleviating vibration and impact of the unit secondary battery 100'on the laminated body 200', a fixing tape 300'surrounding the laminated body 200' may be provided. The fixing tape 300'extends both side portions 100C'and 100D' in which the external terminals 20'of the unit secondary battery 100', which is a component of the laminated body 200', are not arranged in a plan view. They are arranged (see FIGS. 10 and 11).

WO2014 / 00250

Here, the inventors of the present application have found that the following problems can occur in the conventional assembled battery 400'(see FIGS. 10 and 11).

Specifically, the reaction of the unit secondary battery 100', which is a component of the assembled battery 400', is relative to the region 100X'proximal to the installation portion of the external terminal 20' in a plan view. On the other hand, it tends to occur relatively easily in the region 100Y'distal to the installation portion of the external terminal 20'. Therefore, due to this, the reaction of the unit secondary battery 100'may vary as a whole. When the reaction of the unit secondary battery 100'varies, the reaction of the unit secondary battery laminate 200' obtained by laminating a plurality of the unit secondary batteries 100' also varies as a whole due to this. Can occur. From the above, there is a possibility that the assembled battery 400'provided with the unit secondary battery laminate 200'in which the reaction may vary may not be able to suitably exhibit the battery characteristics.

The present invention has been made in view of such circumstances. That is, a main object of the present invention is to provide an assembled battery capable of suitably suppressing variations in battery reaction and a method for producing the same.

In order to achieve the above object, in one embodiment of the present invention,
An assembled battery including a unit secondary battery laminate in which a plurality of unit secondary batteries are stacked.
The assembled battery further includes a tightening member for tightening the unit secondary battery laminate, and the tightening member is viewed from one side of the unit secondary battery in which an external terminal is arranged. An assembled battery is provided that extends to one side and the other.

In order to achieve the above object, in one embodiment of the present invention,
It is a manufacturing method of assembled batteries.
Including a step of laminating a plurality of unit secondary batteries to form a unit secondary battery laminate and a step of tightening the unit secondary battery laminate using a tightening member.
Provided is a manufacturing method in which the tightening member extends from one side portion of the unit secondary battery in which an external terminal is arranged to the other side portion facing the one side portion in a plan view. ..

According to one embodiment of the present invention, it is possible to suitably suppress variations in battery reaction in an assembled battery.

FIG. 1 is a schematic view of an assembled battery according to an embodiment of the present invention. FIG. 2 shows a unit secondary battery having an aspect ratio larger than 1.0 (the length dimension of the side portion where the external terminal is arranged / the length dimension of the side portion extending in a direction substantially perpendicular to the side portion). It is a perspective view which shows typically the assembled battery provided with. FIG. 3 is a perspective view schematically showing an assembled battery including a unit secondary battery having an aspect ratio of 1.0. FIG. 4 is a perspective view schematically showing an assembled battery including a unit secondary battery having an aspect ratio smaller than 1.0. FIG. 5 is a schematic view of a unit secondary battery laminate fastened by a band member of one aspect. FIG. 6 is a schematic view of a unit secondary battery laminate tightened by a band member of another aspect. FIG. 7 is a schematic view of a unit secondary battery laminate tightened by a sandwiching member. FIG. 8 is a graph showing the relationship between the tightening force of the tightening member and the maintenance rate of the battery reaction with respect to the unit secondary battery laminate (each unit secondary battery). FIG. 9 is a cross-sectional view schematically showing the basic configuration of the electrode constituent layer. FIG. 10 is a perspective view schematically showing a conventional assembled battery. FIG. 11 is a plan view schematically showing a unit secondary battery which is a component of a conventional assembled battery.

Hereinafter, the assembled battery according to the embodiment of the present invention will be described with reference to the drawings.

[Basic configuration of assembled battery]
The assembled battery 400 according to the embodiment of the present invention includes at least a unit secondary battery laminate 200 in which a plurality of unit secondary batteries 100 are laminated in one direction (see FIG. 1).

The term "assembled battery" as used herein refers to a battery including a plurality of unit batteries in a broad sense, and refers to a battery including a combination of a plurality of unit secondary batteries in a narrow sense. The term "unit secondary battery" as used herein refers to a single secondary battery included in the assembled battery or a component of the assembled battery, which can be repeatedly charged and discharged. .. The "unit secondary battery" is not overly bound by its name, and may include, for example, a "storage device". The term "planar view" as used herein refers to a state in which an object is viewed from above or below along the direction in which unit secondary batteries are stacked. Further, the "cross-sectional view" or "side view" referred to in the present specification is a state when viewed from a direction substantially perpendicular to the direction in which the unit secondary batteries are stacked.

[Basic configuration of unit secondary battery]
Hereinafter, the basic configuration of the unit secondary battery 100 will be specifically described before the characteristic portion of the assembled battery 400 according to the embodiment of the present invention is described.

As described above, the "unit secondary battery 100" refers to a battery that can be repeatedly charged and discharged. Therefore, the unit secondary battery 100 is not overly bound by its name, and for example, a "storage device" and the like can be included in the subject of the present invention. The unit secondary battery has a structure in which an electrode assembly and an electrolyte are housed and sealed inside an exterior body. The electrode assembly may have a planar laminated structure in which a plurality of electrode constituent layers including a positive electrode, a negative electrode, and a separator are laminated, or a wound structure in which the electrode constituent layers are wound. Further, the exterior body may take the form of a conductive hard case (or flexible case). When the form of the exterior body is a flexible case, each of the plurality of positive electrodes is connected to the external terminal for the positive electrode via the current collecting lead for the positive electrode. The external terminal for the positive electrode is fixed to the exterior body by the seal portion, and the seal portion prevents the electrolyte from leaking. Similarly, each of the plurality of negative electrodes is connected to the external terminal for the negative electrode via the current collecting lead for the negative electrode. The external terminal for the negative electrode is fixed to the exterior body by the seal portion, and the seal portion prevents the electrolyte from leaking. The current collector lead for the positive electrode connected to each of the plurality of positive electrodes may have the function of an external terminal for the positive electrode, and the current collector for the negative electrode connected to each of the plurality of negative electrodes may be provided. The lead may have the function of an external terminal for a negative electrode. When the form of the exterior body is a conductive hard case, each of the plurality of positive electrodes is connected to the external terminal for the positive electrode via the current collecting lead for the positive electrode. The external terminal for the positive electrode is fixed to the exterior body by the seal portion, and the seal portion prevents the electrolyte from leaking.

The positive electrode 10A is composed of at least a positive electrode current collector 11A and a positive electrode material layer 12A (see FIG. 9), and the positive electrode material layer 12A is provided on at least one surface of the positive electrode current collector 11A. A drawer tab on the positive electrode side is positioned at a portion of the positive electrode current collector 11A where the positive electrode material layer 12A is not provided, that is, at the end of the positive electrode current collector 11A. The positive electrode material layer 12A contains a positive electrode active material as an electrode active material. The negative electrode 10B is composed of at least a negative electrode current collector 11B and a negative electrode material layer 12B (see FIG. 9), and a negative electrode material layer 12B is provided on at least one surface of the negative electrode current collector 11B. The negative electrode side drawer tab is positioned at a portion of the negative electrode current collector 11B where the negative electrode material layer 12B is not provided, that is, at the end of the negative electrode current collector 11B. The negative electrode material layer 12B contains a negative electrode active material as an electrode active material.

The positive electrode active material contained in the positive electrode material layer 12A and the negative electrode active material contained in the negative electrode material layer 12B are substances directly involved in the transfer of electrons in the unit secondary battery, and are charge / discharge, that is, positive and negative electrodes responsible for the battery reaction. It is the main substance. More specifically, ions are brought to the electrolyte due to the "positive electrode active material contained in the positive electrode material layer 12A" and the "negative electrode active material contained in the negative electrode material layer 12B", and such ions are brought to the electrolyte with the positive electrode 10A and the negative electrode. It moves to and from 10B, and electrons are transferred to charge and discharge. The positive electrode material layer 12A and the negative electrode material layer 12B are particularly preferably layers capable of occluding and releasing lithium ions. That is, a unit secondary battery in which lithium ions move between the positive electrode 10A and the negative electrode 10B via an electrolyte to charge and discharge the battery is preferable. When lithium ions are involved in charging and discharging, the unit secondary battery corresponds to a so-called "lithium ion battery".

The positive electrode active material of the positive electrode material layer 12A is made of, for example, granules, and a binder (also referred to as “binding material”) is contained in the positive electrode material layer 12A for sufficient contact between particles and shape retention. Is preferable. Further, a conductive auxiliary agent may be contained in the positive electrode material layer 12A in order to facilitate the transfer of electrons that promote the battery reaction. Similarly, when the negative electrode active material of the negative electrode material layer 12B is composed of particles, for example, it is preferable that the negative electrode active material contains a binder for sufficient contact between particles and shape retention, and facilitates the transfer of electrons that promote the battery reaction. The conductive auxiliary agent may be contained in the negative electrode material layer 12B. As described above, the positive electrode material layer 12A and the negative electrode material layer 12B can also be referred to as a "positive electrode mixture layer" and a "negative electrode mixture layer", respectively, because of the form in which a plurality of components are contained.

The positive electrode active material is preferably a substance that contributes to the storage and release of lithium ions. From this point of view, the positive electrode active material is preferably, for example, a lithium-containing composite oxide. More specifically, the positive electrode active material is preferably 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 12A of the unit secondary battery, such a lithium transition metal composite oxide is preferably contained as the positive electrode active material. For example, the positive electrode active material may be lithium cobalt oxide, lithium nickel oxide, lithium manganate, lithium iron phosphate, or a part of the transition metal thereof replaced with another metal. Although such a positive electrode active material may be contained as a single species, two or more species may be contained in combination. In a more preferred embodiment, the positive electrode active material contained in the positive electrode material layer 12A is lithium cobalt oxide.

The binder that can be contained in the positive electrode material layer 12A is not particularly limited, but is not particularly limited, but is a polyvinylidene fluoride, a bilinidene fluoride-hexafluoropropylene copolymer, and a bilinidene fluoride-tetrafluoroethylene copolymer. And at least one selected from the group consisting of polytetrafluoroethylene and the like. The conductive auxiliary agent that can be contained in the positive electrode material layer 12A is not particularly limited, but is carbon black such as thermal black, furnace black, channel black, ketjen black and acetylene black, graphite, carbon nanotubes and vapor phase. At least one selected from carbon fibers such as grown carbon fibers, metal powders such as copper, nickel, aluminum and silver, and polyphenylene derivatives can be mentioned. In a more preferred embodiment, the binder of the positive electrode material layer 12A is polyvinylidene fluoride, and in another more preferred embodiment, the conductive auxiliary agent of the positive electrode material layer 12A is carbon black. In a more preferred embodiment, the binder and conductive aid of the positive electrode material layer 12A are a combination of polyvinylidene fluoride and carbon black.

The negative electrode active material is preferably a substance that contributes to the storage and release of lithium ions. From this point of view, the negative electrode active material is preferably, for example, various carbon materials, oxides, lithium alloys, and the like.

Examples of various carbon materials for the negative electrode active material include graphite (natural graphite, artificial graphite), soft carbon, hard carbon, and diamond-like carbon. In particular, graphite is preferable because it has high electron conductivity and excellent adhesiveness to the negative electrode current collector 11B. 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, for example, Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, It may be a binary, ternary or higher alloy of a metal such as La and lithium. Such oxides are preferably amorphous as their structural form. This is because deterioration due to non-uniformity such as grain boundaries or defects is less likely to occur. In a more preferred embodiment, the negative electrode active material of the negative electrode material layer 12B is artificial graphite.

The binder that can be contained in the negative electrode material layer 12B is not particularly limited, but is at least one selected from the group consisting of styrene-butadiene rubber, polyacrylic acid, polyvinylidene fluoride, polyimide-based resin, and polyamide-imide-based resin. Seeds can be mentioned. In a more preferred embodiment, the binder contained in the negative electrode material layer 12B is styrene-butadiene rubber. The conductive auxiliary agent that can be contained in the negative electrode material layer 12B is not particularly limited, but is carbon black such as thermal black, furnace black, channel black, ketjen black and acetylene black, graphite, carbon nanotubes and vapor phase. At least one selected from carbon fibers such as grown carbon fibers, metal powders such as copper, nickel, aluminum and silver, and polyphenylene derivatives can be mentioned. The negative electrode material layer 12B may contain a component derived from a thickener component (for example, carboxylmethyl cellulose) used at the time of manufacturing the battery.

In a more preferred embodiment, the negative electrode active material and the binder in the negative electrode material layer 12B are a combination of artificial graphite and styrene-butadiene rubber.

The positive electrode current collector 11A and the negative electrode current collector 11B used for the positive electrode 10A and the negative electrode 10B are members that contribute to collecting and supplying electrons generated by the active material due to the battery reaction. Such a current collector may be a sheet-shaped metal member and may have a perforated or perforated form. For example, the current collector may be a metal foil, a punching metal, a net, an expanded metal, or the like. The positive electrode current collector 11A used for the positive electrode 10A is preferably made of a metal foil containing at least one selected from the group consisting of aluminum, stainless steel, nickel and the like, and may be, for example, an aluminum foil. On the other hand, the negative electrode current collector 11B used for the negative electrode 10B is preferably made of a metal foil containing at least one selected from the group consisting of copper, stainless steel, nickel and the like, and may be, for example, a copper foil.

The separator 50 is a member provided from the viewpoint of preventing a short circuit due to contact between the positive and negative electrodes and retaining the electrolyte. In other words, the separator 50 can be said to be a member that allows ions to pass through while preventing electronic contact between the positive electrode 10A and the negative electrode 10B. Preferably, the separator 50 is a porous or microporous insulating member and has a film morphology due to its small thickness. Although only an example, a microporous polyolefin membrane may be used as the separator. In this regard, the microporous membrane used as the separator 50 may contain, for example, only polyethylene (PE) or polypropylene (PP) as the polyolefin. Furthermore, the separator 50 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 coat layer and / or an adhesive layer or the like. The surface of the separator may have adhesiveness.

From the viewpoint of further improving the handling of the electrode, it is preferable that the separator 50 and the electrode (positive electrode 10A / negative electrode 10B) are adhered to each other. For adhesion between the separator 50 and the electrode, an adhesive separator is used as the separator 50, an adhesive binder is applied on the electrode material layer (positive electrode material layer 12A / negative electrode material layer 12B), and / or thermocompression bonding is performed. Can be done by Examples of the adhesive that provides adhesiveness to the separator 50 or the electrode material layer include polyvinylidene fluoride, an acrylic adhesive, and the like.

The electrolyte assists the movement of metal ions released from the electrodes (positive electrode 10A, negative electrode 10B). The electrolyte may be an electrolyte containing a "non-aqueous" solvent such as an organic electrolyte and an organic solvent and a solute, or an "aqueous" electrolyte containing water. The unit secondary battery is preferably a non-aqueous electrolyte secondary battery in which a “non-aqueous” electrolyte is used as the electrolyte. The electrolyte may have a form such as liquid or gel (note that the "liquid" non-aqueous electrolyte is also referred to as "non-aqueous electrolyte solution" in the present specification).

As a specific solvent for the non-aqueous electrolyte, one containing at least carbonate is preferable. Such carbonates may be cyclic carbonates and / or chain carbonates. Although not particularly limited, 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 the chain carbonates include at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and dipropyl carbonate (DPC). In a preferred embodiment, a combination of cyclic carbonates and chain carbonates is used as the non-aqueous electrolyte, for example a mixture of ethylene carbonate and diethyl carbonate. Further, as a specific solute of the non-aqueous electrolyte, for example, Li salts such as LiPF ₆ and LiBF ₄ are used. Further, as a specific solute of the non-aqueous electrolyte, for example, Li salts such as LiPF ₆ and LiBF ₄ are used.

As the positive electrode current collector lead and the negative electrode current collector lead, any current collector lead used in the field of secondary batteries can be used. Such a current collecting lead may be composed of a material in which electron transfer can be achieved, and is composed of a conductive material such as aluminum, nickel, iron, copper, or stainless steel. The positive electrode current collecting lead is preferably made of aluminum, and the negative electrode current collecting lead is preferably made of nickel. The form of the positive electrode current collecting lead and the negative electrode current collecting lead is not particularly limited, and may be, for example, a wire or a plate.

As the external terminal, any external terminal used in the field of secondary batteries can be used. Such external terminals may be made of a material in which electron transfer can be achieved, and are usually made of a conductive material such as aluminum, nickel, iron, copper, stainless steel. The external terminal 5 may be electrically and directly connected to the substrate, or may be electrically and indirectly connected to the substrate via another device. Not limited to this, the positive electrode current collector lead connected to each of the plurality of positive electrodes may have the function of the positive electrode external terminal, and the negative electrode current collector connected to each of the plurality of negative electrodes. The lead may have the function of an external terminal for a negative electrode.

The exterior body may have the form of a conductive hard case (or flexible case) as described above.

The conductive hard case consists of a main body and a lid. The main body is composed of a bottom portion and a side surface portion constituting the bottom surface of the exterior body. The body and lid are sealed after accommodating the electrode assembly, electrolyte, current collector leads and external terminals. The sealing method is not particularly limited, and examples thereof include a laser irradiation method. As the material for forming the main body and the lid, any material that can form a hard case type exterior body can be used in the field of the secondary battery. Such a material may be any material from which electron transfer can be achieved, including conductive materials such as aluminum, nickel, iron, copper and stainless steel. The dimensions of the main body and the lid are mainly determined according to the dimensions of the electrode assembly. For example, when the electrode assembly is housed, the dimensions are such that the movement (misalignment) of the electrode assembly inside the exterior body is prevented. It is preferable to have. By preventing the electrode assembly from moving, the electrode assembly is prevented from being destroyed, and the safety of the unit secondary battery is improved.

The flexible case is composed of a soft sheet. The soft sheet may have sufficient softness to achieve bending of the seal portion, and is preferably a plastic sheet. The plastic sheet is a sheet having a property of maintaining deformation due to an external force when it is removed after applying an external force. For example, a so-called laminated film can be used. A flexible pouch made of a laminated film can be manufactured, for example, by laminating two laminated films and heat-sealing the peripheral portion thereof. As the laminated film, a film in which a metal foil and a polymer film are laminated is generally used, and specifically, a three-layer structure composed of an outer layer polymer film / metal foil / inner layer polymer film is exemplified. The outer layer polymer film is for preventing damage to the metal foil due to permeation of moisture and the like and contact, and polymers such as polyamide and polyester can be preferably used. The metal foil is for preventing the permeation of moisture and gas, and foils such as copper, aluminum, and stainless steel can be preferably used. The inner layer polymer film is for protecting the metal foil from the electrolyte stored inside and for melt-sealing at the time of heat sealing, and polyolefin or acid-modified polyolefin can be preferably used.

[Characteristic part of the assembled battery of the present invention]
After explaining the basic configuration of the unit secondary battery 100 above, the feature portions of the present invention will be specifically described below.

Hereinafter, terms used in the present specification will be defined prior to the specific description of the characteristic portions of the present invention. As described above, the term "assembled battery" as used herein refers to a battery including a plurality of unit batteries in a broad sense, and a battery including a combination of a plurality of unit secondary batteries in a narrow sense. As described above, the "unit secondary battery" referred to in the present specification is a single secondary battery included in the assembled battery or a component of the assembled battery, and can be repeatedly charged and discharged. Refers to a battery. The "unit secondary battery laminate" as used herein refers to a structure in which a plurality of unit secondary batteries are laminated in one direction (stacking direction). The "tightening member" as used herein refers to a member that tightens the unit secondary battery laminate while applying a predetermined force, and instead, a pressing member, a shrinking member, or the like, which is applied to the unit secondary battery laminate. Or, it refers to a member that functions as a sandwiching member.

The term "external terminal" as used herein refers to a battery that is arranged so as to project outward from each of a plurality of unit secondary batteries in a plan view and that can be electrically connected to an external medium. The "side portion of the unit secondary battery" as used herein refers to the outer edge portion of the unit secondary battery in a broad sense, and refers to the outer edge portion of the exterior body which is a component of the unit secondary battery in a narrow sense. The "protruding direction of the external terminal" as used herein refers to a direction in which the external terminal extends so as to protrude from the unit secondary battery in a plan view. In the present specification, "the tightening member extends in a direction substantially parallel to the protruding direction of the external terminal in a plan view" means that the tightening member extends in a plan view of the external terminal. It refers to a state in which it extends in substantially the same direction as the projecting direction. The "one main surface of the unit secondary battery laminate" as used herein refers to a surface extending in a direction substantially perpendicular to the stacking direction of the unit secondary battery in a broad sense, and a unit in a narrow sense. The unit of the outermost layer, which is a component of the secondary battery laminate, corresponds to the main surface of the secondary battery.

The "ring-shaped band member" as used herein refers to a band-shaped member that continuously forms an arc shape. The "elastic member" referred to in the present specification has extensibility when installed in the unit secondary battery laminate, and has contractility with respect to the unit secondary battery laminate after the installation in the unit secondary battery laminate is completed. Refers to a member. The "outer surface of the unit secondary battery laminate" as used herein refers to an exposed surface of the unit secondary battery laminate (a surface along the stacking direction of the unit secondary battery and a direction substantially perpendicular to the surface). (Two facing surfaces extending to). In the broad sense, the "rectangular shape" as used herein refers to a shape that is square and rectangular in a plan view, and in a narrow sense, one side and the other that is continuous with the other side in a plan view. It refers to a shape in which the angle of a corner portion (corner portion) formed by a side is 90 degrees. The "aspect ratio" as used herein refers to the ratio of the long side to the short side in a rectangle in a broad sense, and in a narrow sense, the external terminal of the unit secondary battery is arranged on one side in a plan view. , Refers to the ratio to the side extending in a direction substantially perpendicular to one side.

The inventor of the present application has diligently studied countermeasures for providing the assembled battery 400 capable of suitably suppressing variations in battery reaction. Specifically, variations in battery reaction are likely to occur relatively in the region 100X'proximal to the installation portion of the external terminal 20'in a plan view, while the installation portion of the external terminal 20' In view of the fact that the region 100Y'on the distal side tends to be relatively unlikely to occur (see FIG. 11), improvement measures for improving such a tendency were enthusiastically studied. As a result, the present invention has been devised.

The present invention (assembled battery 400) devised to improve such a tendency further provides a tightening member 300 for tightening the unit secondary battery laminate 200, which is a component thereof, and the tightening member 300 is flattened. Visually, the technical idea of arranging the unit secondary battery 100 in which the external terminal 20 is arranged so as to extend from one side portion 100A to the other side portion 100B facing the one side portion 100A. Have.

According to such a technical idea, in the present invention, first, the tightening member 300 for tightening the unit secondary battery laminate 200 is one side of the unit secondary battery 100 in which the external terminal 20 is arranged in a plan view. It needs to be provided so as to extend from the portion 100A to the other side portion 100B. Further, according to such a technical idea, in the present invention, secondly, the tightening member 300 "at least" in order to preferably exert the function of tightening the unit secondary battery laminate 200. It needs to be provided to both the one facing outer surface of the 200 and the other outer surface facing the one outer surface. More specifically, the tightening member 300 is the outermost layer located on one outer surface side of the unit secondary battery laminate 200 in order to preferably exert the function of tightening the unit secondary battery laminate 200. It is necessary to be provided to the unit secondary battery 100 of the above and the unit secondary battery 100 of the outermost layer located on the outer surface side of the other.

Summarizing the above two points, in the present invention, in the plan view, the tightening member 300 is a side portion 100A on which the external terminal 20 of the unit secondary battery 100 of the outermost layer of "one side" is arranged. It needs to be provided so as to extend from the to the other side 100B. Further, in the present invention, in the plan view, the tightening member 300 is from one side portion 100A to the other side portion 100B in which the external terminal 20 of the unit secondary battery 100 of the "other" outermost layer is arranged. It needs to be offered to be extended.

When the tightening member 300 adopts such an arrangement form, the first feature of the present invention is that the tightening force of the tightening member 300 is the unit secondary battery 100 of the outermost layer of "one side" in a plan view. The external terminal 20 is provided in a region extending from one side portion 100A to the other side portion 100B. Further, when the tightening member 300 adopts such an arrangement form, in the present invention, as a second feature, the tightening force of the tightening member 300 is the unit secondary of the outermost layer of the "other" in a plan view. The battery 100 is provided in a region extending from one side portion 100A where the external terminal 20 is arranged to the other side portion 100B.

Further, when the tightening member 300 adopts such an arrangement form, in the present invention, as a third feature, it is provided to the unit secondary battery 100 side of the outermost layer of "one side" in a cross-sectional view or a side view. The direction in which the tightening force of the tightening member 300 acts and the direction in which the tightening force of the tightening member 300 provided on the unit secondary battery 100 side of the "other" outermost layer acts are opposite to each other. It becomes. That is, the fact that the directions of action of the tightening forces are opposite to each other means that one main surface 200α of the unit secondary battery laminate 200 (the installation side of the unit secondary battery 100 in the outermost layer of “one”) and one side. It means that the other main surface 200β facing the main surface 200α (the installation side of the unit secondary battery 100 of the outermost layer of the “other”) is sandwiched by the tightening member 300 (see FIG. 1). More specifically, the fact that the directions of action of the tightening forces are opposite to each other is due to the fact that the tightening member 300 is a member that provides the tightening force, so that one main surface 200α and the other It means that the main surface 200β of the above is pressed by the tightening member 300. From the above, since the directions of action of the tightening forces are opposite to each other, the tightening force of the tightening member 300 is from the unit secondary battery 100 of the outermost layer of "one" in a side view or a cross-sectional view. It can be provided to all the unit secondary batteries 100 up to the unit secondary battery 100 of the outermost layer of the "other".

In view of the first feature and the second feature described above, the tightening force of the tightening member 300 is such that the external terminal 20 of the unit secondary battery 100 of the "outermost layer" is arranged. It can be provided in a region extending from one side 100A to the other 100B. Therefore, in a plan view, the tightening member 300 is uniform over the entire region from one side portion 100A to the other side portion 100B where the external terminal 20 of the unit secondary battery 100 of the "outermost layer" is arranged. It becomes possible to provide a tightening force. That is, the tightening force of the tightening member 300 is applied to any part in the region from one side portion 100A to the other side portion 100B where the external terminal 20 of the unit secondary battery 100 of the "outermost layer" is arranged. Can be uniformly provided.

Further, in view of the above-mentioned third feature, as described above, the tightening force of the tightening member 300 is "one" from the unit secondary battery 100 of the outermost layer "the other" in cross-sectional view or side view. It can be provided to all the unit secondary batteries 100 up to the unit secondary battery 100 of the outermost layer of the above. Therefore, due to this, the technical effect in the "outermost layer" unit secondary battery 100 played according to the above first and second features is all other than the outermost layer unit secondary battery 100. It can also be played in the unit secondary battery 100 of.

From the above, when the above three features are combined, the tightening force of the tightening member 300 is the outside of each of all the unit secondary batteries 100 (corresponding to the unit secondary battery laminate 200) in a plan view. It may be provided in a region extending from one side 100A where the terminal 20 is arranged to the other 100B. Therefore, in a plan view, the entire region from one side portion 100A to the other side portion 100B where the external terminals 20 of all the unit secondary batteries 100 (corresponding to the unit secondary battery laminate 200) are arranged. , It becomes possible to provide a uniform tightening force of the tightening member 300. That is, in a plan view, any part in the region from one side portion 100A to the other side portion 100B where the external terminal 20 of each unit secondary battery 100 (corresponding to the unit secondary battery laminate 200) is arranged. In addition, the tightening force of the tightening member 300 can be uniformly applied.

As a result, in a plan view, the electrode assembly (for example, each positive electrode and each negative electrode) in each unit secondary battery 100 is tightened to any part in the region from one side to the other. It is possible to transmit a uniform tightening force of the member 300. From the viewpoint of improving the ease with which the tightening force can be more preferably transmitted to the inside of each unit secondary battery 100, the material of the exterior body (hard case type) of each unit secondary battery 100 is aluminum, nickel, or the like. Examples thereof include iron, copper and stainless steel, and among these, aluminum is particularly preferable. Therefore, in a plan view, it is possible to make the battery reaction (chemical reaction) inside each unit secondary battery 100 located in the region substantially uniform. As a result, the battery reaction of each unit secondary battery 100 can be made substantially uniform as a whole, that is, the variation in the battery reaction can be seen in plan view from all the unit secondary batteries 100 (unit secondary battery laminate 200). It is possible to preferably suppress that each external terminal 20 (corresponding to) can occur in the region from one side portion 100A to the other side portion 100B where the external terminals 20 are arranged. Therefore, as a whole, the technical effect of suppressing the generation of variations in the battery reaction within the region of the unit secondary battery laminate 200 in a plan view can be achieved.

Since the assembled battery 400 of the present invention includes the unit secondary battery laminate 200 that exerts such an effect, the battery reaction (chemical reaction) during charging and discharging of the assembled battery 400 is caused by the technical effect. The speed and the like can be made substantially constant as a whole. Further, since the assembled battery 400 includes the unit secondary battery laminate 200 that exerts such an effect, due to the technical effect, the assembled battery 400 (for example, under low temperature conditions (for example, 0 degrees or less)). The charging reaction proceeds locally during charging, whereby the local generation of the region where lithium can be deposited can be suitably suppressed. By suppressing the local generation of the lithium precipitation region, damage to the separator in each unit secondary battery 100 due to lithium precipitation can be suitably suppressed. From the above, the assembled battery 400 of the present invention can preferably exhibit the battery characteristics.

(Manufacturing method of assembled battery of the present invention)
It should be noted that the method for manufacturing the assembled battery of the present invention having the above characteristics will be mentioned.

1. 1. Step of Forming Unit Secondary Battery Laminated Body 200 First, a plurality of unit secondary battery 100s are laminated along one direction (that is, the stacking direction), thereby forming the unit secondary battery laminate 200 (see FIG. 1). ..

2. Step of providing the tightening member After forming the unit secondary battery laminate 200, the unit secondary battery laminate 200 is tightened using the tightening member 300. Specifically, at this time, in a plan view, the tightening member 300 is attached to the other side portion facing the one side portion 100A from the one side portion 100A of the unit secondary battery 100 in which the external terminal 20 is arranged. Arrange so as to extend to 100B. Specifically, the tightening member 300 is attached to one main surface 200α of the unit secondary battery laminate 200 (the installation side of the unit secondary battery 100 in the outermost layer of “one”) and one main surface 200α. It is arranged so as to sandwich the other main surface 200β (the installation side of the unit secondary battery 100 of the outermost layer of the “other”) facing the other (see FIG. 1).

3. 3. Completion of the assembled battery With the above, the assembled battery of the present invention can be obtained.

The detailed operation and effect will be simplified because they are described in the above-described constituent parts of the assembled battery of the present invention, but according to the manufacturing method of the present invention, the external terminals of each unit secondary battery 100 in plan view. It is possible to provide a uniform tightening force of the tightening member 300 over the entire region from one side portion 100A to the other side portion 100B where 20 is arranged. Thereby, in plan view and in plan view, any part in the region from one side portion to the other side portion of the electrode assembly (for example, each positive electrode and each negative electrode) in each unit secondary battery 100. Also, a uniform tightening force of the tightening member 300 can be transmitted. Therefore, in a plan view, it is possible to make the battery reaction (chemical reaction) inside each unit secondary battery 100 located in the region substantially uniform. Thereby, each battery reaction of all the unit secondary batteries 100 (corresponding to the unit secondary battery laminate 200) can be made substantially uniform.

The assembled battery of the present invention preferably adopts the following aspects.

In one aspect, it is preferable that the tightening member 300 extends in a direction substantially parallel to the protruding direction of the external terminal 20 of the unit secondary battery 100 in a plan view (see FIG. 1).

As described above, from the viewpoint of suppressing the occurrence of variation in the battery reaction of all the unit secondary batteries 100, in the present invention, the tightening member 300, which is a component thereof, has the external terminal 20 in a plan view. The unit secondary battery 100 is arranged so as to extend from one side portion 100A to the other side portion 100B. In this embodiment, from the viewpoint of more preferably applying the tightening force of the tightening member 300, the extending direction (that is, the arrangement location) of the tightening member 300 in a plan view is set to the external terminal 20 of the unit secondary battery 100. It is limited to a direction substantially parallel to the protruding direction.

Regarding this, when the extending direction of the tightening member 300 is limited to a direction substantially parallel to the protruding direction of the external terminal 20 of the unit secondary battery 100, the unit in which the external terminal 20 is arranged in a plan view. One side portion 100A of the secondary battery 100 and the other side portion 100B on the opposite side of the one side portion 100A may be in a completely opposite relationship. Due to such a completely opposed relationship, one side portion 100A and the other side portion 100B of the unit secondary battery 100 in which the external terminal 20 is arranged are tightened as compared with the case where they are partially opposed to each other in a plan view. Since the attachment member 300 does not extend diagonally in a plan view, it is possible to suppress the dispersion of the tightening force of the tightening member 300. That is, due to the completely opposed relationship, the tightening force of the tightening member 300 can be more preferably applied. From the above, if the extending direction of the tightening member 300 is limited to a direction substantially parallel to the protruding direction of the external terminal 20 of the unit secondary battery 100 in a plan view, the tightening member 300 is tightened. It becomes possible to apply the force more favorably. In the above points, it can be said that this aspect is preferable.

In one aspect, in a plan view, the external terminal 20A on the positive electrode side and the external terminal 20B on the negative electrode side are arranged on one side 100A of the unit secondary battery 100 so as to be separated from each other, and the tightening member 300. However, in a plan view, it is preferable that the external terminal 20A on the positive electrode side and the external terminal 20B on the negative electrode side are arranged (see FIG. 1).

As described above, the variation in the battery reaction of each unit secondary battery 100'is likely to occur relatively in the region 100X'proximal to the installation portion of the external terminal 20' in a plan view, while the variation is likely to occur. In the region 100Y'distal to the installation portion of the external terminal 20', it tends to be relatively difficult to occur (see FIG. 11). Regarding this, more specifically, in a plan view, the reaction of each positive electrode of the unit secondary battery 100'is relatively relative to the installation portion of the external terminal 20A'on the positive electrode side in the region 100X'on the proximal side. On the other hand, the reaction of each positive electrode of the unit secondary battery 100'is relatively likely to occur in the region 100Y'distal to the installation portion of the external terminal 20A'on the positive electrode side. Similarly, in a plan view, the reaction of each negative electrode of the unit secondary battery 100'is relatively likely to occur in the region 100X'proximal to the installation portion of the external terminal 20B'on the negative electrode side, while the reaction of each negative electrode is relatively likely to occur. In the region 100Y'distal to the installation portion of the external terminal 20B'on the negative electrode side, the reaction of each negative electrode of the unit secondary battery 100'is relatively likely to occur. From the above, it is preferably required to suppress the variation in the reaction of each positive electrode and each negative electrode of the unit secondary battery.

In order to suppress variations in the reaction of each positive electrode of the unit secondary battery 100, the external terminal 20A on the positive electrode side of the unit secondary battery 100 is arranged so that the tightening force of the tightening member 300 is in plan view. It is necessary to be provided substantially uniformly to any portion in the region from one side portion 100A to the other side portion 100B. Similarly, in order to suppress variations in the reaction of each negative electrode of the unit secondary battery 100, the tightening force of the tightening member 300 is the external terminal 20B on the negative electrode side of the unit secondary battery 100 in a plan view. It is necessary to be provided substantially uniformly to any portion in the region from one side portion 100A to the other side portion 100B on which the is arranged.

In view of the above points, the tightening member 300 is preferably arranged between the external terminal 20A on the positive electrode side and the external terminal 20B on the negative electrode side in a plan view (see FIG. 1). According to such an arrangement form, the tightening force of the tightening member 300 is measured in a plan view because the tightening member 300 is arranged between the external terminal 20A and the external terminal 20B in a plan view. , "A region from one side 100A where the external terminal 20A on the positive electrode side of the unit secondary battery 100 is arranged to the other side 100B" and "the external terminal 20B on the negative electrode side of the unit secondary battery 100 are arranged". It is possible to suitably provide both regions of "a region extending from one side portion 100A to the other side portion 100B". In the above points, it can be said that this aspect is preferable.

In one aspect, the unit secondary battery 100 may have a rectangular shape in a plan view (see FIG. 1 and the like).

As described above, the main feature of the present invention is that the tightening force of the tightening member 300 is applied over the entire region from one side portion 100A to the other side portion 100B of each unit secondary battery 100. .. In the present invention, the plan-view shape of the unit secondary battery 100 is not particularly limited as long as such a feature is realized. However, in consideration of the actual form (rectangular parallelepiped) of the drive power source for electric bikes, electric bicycles, electric vehicles, etc. and the ease of installation in the drive power source, the unit secondary battery 100, which is a component of the assembled battery 400, is , It is preferable to have a rectangular shape in a plan view. The unit secondary battery 100 is not limited to this, and may have a circular shape, an elliptical shape, or the like in a plan view.

In one aspect, the unit secondary battery 100 has an aspect ratio of one side portion 100A in which the external terminal 20 is arranged with respect to the side portion 100C extending in a direction substantially perpendicular to the one side portion 100A. It is preferably 0 or more (see FIGS. 2 and 3).

As described above, the main feature of the present invention is that the tightening force of the tightening member 300 is applied over the entire region from one side portion 100A to the other side portion 100B of each unit secondary battery 100. .. According to these characteristics, in the assembled battery 400 of the present invention, it is possible to ensure substantially constantness such as the speed and number of battery reactions (chemical reactions) during charging and discharging of the assembled battery 400, and to ensure that the lithium assembly battery 400 is charged. The technical effect of suppressing the local generation of the region where precipitation can occur can be achieved.

With respect to this, in order to more preferably exert such a technical effect, the tightening force may be more actively performed between one side portion 100A and the other side portion 100B of the unit secondary battery 100 in a plan view. It is preferable that the length dimension of the battery reaction (chemical reaction) region is relatively small. This is based on the viewpoint that "when the assembled battery 400 is charged, the battery reaction in the region is performed more quickly, and the local occurrence location of the lithium precipitation region is reduced as much as possible".

More preferably, the aspect shown in FIG. 2 can be mentioned as an aspect for realizing such a viewpoint. In the embodiment shown in FIG. 2, the unit secondary battery 100 has an aspect ratio of one side portion 100A in which the external terminal 20 is arranged with respect to the side portion 100C extending in a direction substantially perpendicular to the one side portion 100A. (A ₁ / a ₂ ) is larger than 1.0. That is, in the embodiment shown in FIG. 2, when the unit secondary battery 100 has a rectangular shape in a plan view, the length of one side portion 100A in which the external terminal 20 is arranged is different from that of the one side portion 100A. It is relatively larger than the length of the side portion 100C extending in a substantially vertical direction. In other words, when the unit secondary battery 100 has a rectangular shape in a plan view, the length of the side portion 100C extending in a direction substantially perpendicular to one side portion 100A on which the external terminal 20 is arranged is long. , It is relatively smaller than the length of one side portion 100A on which the external terminal 20 is arranged. Therefore, due to this, according to the embodiment shown in FIG. 2, "when the assembled battery 400 is charged, the battery reaction in the region can be performed more quickly, and the location where the lithium precipitation region is locally generated can be formed. It is possible to more preferably carry out "reduce as much as possible".

Without being limited to this, the embodiment shown in FIG. 3 is preferable. In the embodiment shown in FIG. 3, the unit secondary battery 100 has an aspect ratio of one side portion 100A in which the external terminal 20 is arranged with respect to the side portion 100C extending in a direction substantially perpendicular to the one side portion 100A. (A ₁ / a ₂ ) is 1.0. That is, in the embodiment shown in FIG. 3, when the unit secondary battery 100 has a rectangular shape in a plan view, the length of one side portion 100A in which the external terminal 20 is arranged and the length of one side portion 100A are approximately the same. The length of the side portion 100C extending in the vertical direction is substantially the same. Therefore, due to this, according to the embodiment shown in FIG. 3, "when the assembled battery 400 is charged, the battery reaction in the region can be performed more quickly, and the location where the lithium precipitation region is locally generated can be formed. It is possible to preferably carry out "reduce as much as possible".

When the assembled battery 400 including the unit secondary battery laminate 200 of the present invention is used as a drive power source for an electric bike, an electric bicycle, an electric vehicle, or the like, each unit secondary battery is shown in FIGS. 2 and 3. The external terminals 20 of 100 are arranged so as to be oriented upward. That is, each unit secondary battery 100 is arranged so that the side portion 100C of the unit secondary battery 100 corresponds to the height of the unit secondary battery 100. This means that the height of the assembled battery 400 corresponds to the length of the side portion 100C of the unit secondary battery 100. Therefore, if the length dimension of the side portion 100C of the unit secondary battery 100 is relatively large, the height dimension of the assembled battery 400 can be increased accordingly. If the height dimension of the assembled battery 400 is large, there is a possibility that the installation space for an electric motorcycle, an electric bicycle, an electric vehicle, or the like cannot be suitably secured accordingly. From this point of view, it is preferable to adopt the embodiment shown in FIGS. 2 and 3 in which the length dimension of the side portion 100C of the unit secondary battery 100 does not become relatively large.

As a confirmation addition, as described above, the present invention applies the tightening force of the tightening member 300 over the entire region from one side 100A to the other side 100B of each unit secondary battery 100. The main feature is that. Technical effects based on these main features (ensuring substantially constantness such as the speed and number of battery reactions (chemical reactions) during charging and discharging of the assembled battery 400, and the region where lithium can be deposited during charging of the assembled battery 400 From the viewpoint of more preferably performing local generation suppression), the embodiments shown in FIGS. 2 and 3 are preferable. However, if the tightening force of the tightening member 300 is applied over the entire region from one side 100A of each unit secondary battery 100 to the other side 100B, the embodiments shown in FIGS. 2 and 3. The embodiment shown in FIG. 4 may be adopted without being limited to. In the embodiment shown in FIG. 4, the unit secondary battery 100 has an aspect ratio of one side portion 100A in which the external terminal 20 is arranged with respect to the side portion 100C extending in a direction substantially perpendicular to the one side portion 100A. (A ₁ / a ₂ ) is smaller than 1.0. That is, when the unit secondary battery 100 has a rectangular shape in a plan view, the length of one side portion 100A on which the external terminal 20 is arranged extends in a direction substantially perpendicular to the one side portion 100A. It may be relatively smaller than the length of the side portion 100C. In other words, when the unit secondary battery 100 has a rectangular shape in a plan view, the length of the side portion 100C extending in a direction substantially perpendicular to one side portion 100A on which the external terminal 20 is arranged is long. , The length of the one side portion 100A on which the external terminal 20 is arranged may be relatively larger than the length.

From the above, the aspect ratio (a ₁ / a ₂ ) is preferably 1.0 or more. However, without being limited to this, in view of the fact that the assembled battery 400 of the present invention is used as a driving power source for an electric motorcycle, an electric bicycle, an electric vehicle, etc., the aspect ratio (a ₁ / a ₂ ) is 0. It may be 5 or more and 2.0 or less, for example, 0.8 or more and 1.7 or less.

The present invention may take the following aspects.

In one aspect, the tightening member 300 may be a ring-shaped band member 301 (FIGS. 5: 301A, FIG. 6: 301B), and the band member 301 may be an elastic member (see FIGS. 5 and 6). ..

As described above, the main feature of the present invention is that the tightening force of the tightening member 300 is applied over the entire region from one side portion 100A to the other side portion 100B of each unit secondary battery 100. .. In the present invention, the configuration of the tightening member 300 is not particularly limited as long as such a feature is realized.

Therefore, as an example, as shown in FIG. 5, a ring-shaped band member 301A (that is, a ring-shaped band member) may be used. When the ring-shaped band member 301A is used, the outer surface 200γ of the unit secondary battery laminate 200 is surrounded by the band member 301A due to the band member 301A taking the ring form. When the band member 301A surrounds the outer surface 200γ of the unit secondary battery laminate 200, the stacking is caused to the local portion of the unit secondary battery laminate 200 surrounded by the band member 301A. Pushing pressure can occur that acts on the inner region of the body. The generation of such a pressing force means that a tightening force of the band member 301A can be substantially generated with respect to the local portion of the unit secondary battery laminate 200. As a result, even when the ring-shaped band member 301A is used as the tightening member 300, the tightening force of the band member 301A is such that the external terminal 20 of each unit secondary battery 100 is arranged in a plan view. It can be provided in a region extending from one side 100A to the other 100B. Therefore, in a plan view, it is possible to provide a uniform tightening force of the band member 301A over the entire region from one side portion 100A where the external terminal 20 of each unit secondary battery 100 is arranged to the other side portion 100B. It will be possible.

Since the operation and effect are the same as those shown in FIG. 5, no duplicate description will be made, but the configuration of the tightening member 300 is not limited to the aspect shown in FIG. 5, and the ring-shaped band member 301B ( (Corresponding to a cable tie type) may be used (see FIG. 6).

Further, in the embodiment shown in FIGS. 5 and 6, both sides of the conventional embodiment shown in FIGS. 10 and 11 (the fixed tape 300'is not arranged with the external terminal 20'of the unit secondary battery 100'in a plan view. The following effects can be achieved as compared with (a mode in which 100C'and 100D' are arranged so as to extend). Specifically, when the assembled battery 400 of the present invention is used as a drive power source for an electric bike, an electric bicycle, an electric vehicle, etc., the external terminal 20 of each unit secondary battery 100 is arranged so as to be oriented upward. Often done. In such an arrangement, when gravity acts on the tightening member 300, a force that causes the tightening member 300 to move in the direction of gravity (substantially downward direction) tends to act due to this. On the other hand, when the external terminal 20 of the unit secondary battery 100 is arranged so as to be oriented upward, the one side portion 100A on which the external terminal 20 is arranged is the unit secondary battery 100, that is, the unit secondary. It substantially bears the upper surface of the battery laminate 200. In this case, a part of the band member 301 is positioned on the upper surface of the unit secondary battery laminate 200. Therefore, due to the fact that a part of the band member 301 is positioned on the upper surface of the unit secondary battery laminate 200, the upper surface of the unit secondary battery laminate 200 is in the direction of gravity (substantially downward direction) of the band member 301. Can be suitable as a stopper wall for movement to. On the other hand, in the conventional embodiments shown in FIGS. 10 and 11, there is no stopper wall for moving the fixing tape 300'in the gravity direction (substantially downward direction). From the above, the embodiment shown in FIGS. 5 and 6 preferably suppresses the displacement of the band member 301 (that is, the tightening member) along the direction of gravity as compared with the conventional embodiments shown in FIGS. 10 and 11. It is possible to do.

Further, when the assembled battery 400 of the present invention is used as a drive power source for an electric motorcycle, an electric bicycle, an electric vehicle, or the like, the assembled battery 400 may be tilted depending on the usage environment. The inclination of the assembled battery 400 means that the external terminal 20 of the unit secondary battery 100 is not necessarily oriented vertically upward. In this case, in the embodiments shown in FIGS. 5 and 6, the following effects can be achieved as compared with the conventional embodiments shown in FIGS. 10 and 11. Specifically, in the conventional embodiments shown in FIGS. 10 and 11, if the external terminal 20'of the unit secondary battery 100'is not oriented upward, the external terminal 20'is installed in the external terminal 20'. On the other hand, there may be a gap between the fixing tape 300'which can be located on the proximal region 100X'and the unit secondary battery laminate 200'. On the other hand, in the embodiment shown in FIGS. 5 and 6, even if the external terminal 20 of the unit secondary battery 100 is not oriented upward, it is proximal to the installation portion of the external terminal 20 due to this. It is possible to suitably suppress the formation of a gap between the band member 301 (that is, the tightening member) that can be located on the side region 100X and the unit secondary battery laminate 200.

From the above, in the embodiment shown in FIGS. 5 and 6, suitable suppression of displacement of the band member 301 (that is, the tightening member) along the direction of gravity and / or the band member 301 (that is, the tightening member) It is possible to suppress the gap between the unit and the unit secondary battery laminate 200. Therefore, due to this, in a plan view, from one side portion 100A to the other side portion 100B where the external terminal 20 of each unit secondary battery 100 (corresponding to the unit secondary battery laminate 200) is arranged. It is possible to "continuously and stably" apply the tightening force of the tightening member 300 uniformly to any portion in the region.

In one aspect, the tightening member 300 may be a sandwiching member 302 (see FIG. 7).

Similarly, if the feature of providing the tightening force of the tightening member 300 over the entire region from one side 100A to the other side 100B of each unit secondary battery 100 is realized, the tightening member The configuration of 300 is not limited to the embodiments shown in FIGS. 5 and 6.

As an example, as shown in FIG. 7, a sandwiching member 302 (a band-shaped sandwiching member in a plan view) may be used. In this embodiment, the sandwiching member 302 may have a function of sandwiching one main surface 200α and the other main surface 200β of the unit secondary battery laminate 200 from each other in a side view or a cross-sectional view. Therefore, when the sandwiching member 302 is used, the unit secondary battery laminate 200 is sandwiched by the sandwiching member 302. More specifically, one main surface 200α of the unit secondary battery laminate 200 and the other main surface 200β facing the one main surface 200α are sandwiched by the sandwiching member 302.

The sandwiching by the sandwiching member 302 may generate a sandwiching force with respect to the local portion of the unit secondary battery laminate 200 sandwiched by the sandwiching member 302. More specifically, one of the sandwiching members 302A facing each other presses one main surface 200α of the unit secondary battery laminate 200 in one direction (corresponding to the direction of the right arrow in FIG. 7). Apply pressure. On the other hand, the other sandwiching member 302B exerts a pressing force pressing the other main surface 200β in the direction opposite to one direction (corresponding to the direction of the left arrow in FIG. 7). That is, the directions in which the pressing force acts are opposite to each other. By adopting such a relationship, the sandwiching member 302 can suitably generate a pressing force in the inner region of the laminated body 200 with respect to the local portion of the unit secondary battery laminated body 200.

From the above, even when the sandwiching member 302 is used as the tightening member 300, the pressing force that can be generated by the sandwiching member 302 acts on each unit secondary battery 100 in a plan view. Specifically, the pressing force may be applied to a region extending from one side portion 100A where the external terminal 20 of each unit secondary battery 100 is arranged to the other side portion 100B. That is, in a plan view, the pressing force by the sandwiching member 302 can be uniformly applied over the entire region from one side portion 100A where the external terminal 20 of each unit secondary battery 100 is arranged to the other side portion 100B. It will be possible.

In one aspect, the tightening force of the tightening member with respect to the unit secondary battery laminate 200 may be 50 N or more and 100 N or less (see FIGS. 1 and 8).

The assembled battery 400 including the unit secondary battery laminate 200 of the present invention is used as a drive power source for an electric motorcycle, an electric bicycle, an electric vehicle, or the like. That is, it can be said that the assembled battery 400 of the present invention is a power source having a relatively large battery capacity. Therefore, the tightening force of the tightening member 300, which is a component of the assembled battery 400 of the present invention, with respect to the unit secondary battery laminate 200 is required to be relatively large. Specifically, as shown in FIG. 8, when the tightening force of the tightening member with respect to the unit secondary battery laminate 200 (that is, each unit secondary battery 100) is 50 N or more and 400 N or less, the tightening force is applied. Therefore, it is clear from the results of numerical analysis that the battery reaction of each unit secondary battery 100 can be stably maintained (that is, the maintenance rate of the battery reaction is about 70 to 80%) (that is, the maintenance rate of the battery reaction is about 70 to 80%). See Table 1 below).

[Table 1]

The basic data of the unit secondary battery laminate 200 (or the unit secondary battery 100) used in the numerical analysis is as follows.
-Length of the side part on the external terminal installation side: 60 mm
-The length of the side extending approximately perpendicular to the side where the external terminal is installed: 100 mm
・ Length along the stacking direction of the unit secondary battery: 10 mm
・ Unit Secondary battery exterior material: Aluminum laminate

The assembled battery according to the embodiment of the present invention can be used in various fields where storage is expected. It is just an example, but it is used for home / small industrial applications (for example, power tools, golf carts, household / nursing / industrial robots), and large industrial applications (for example, forklifts, elevators, and bay port cranes). , Transportation system field (for example, hybrid vehicle, electric vehicle, bus, train, electric assist bicycle, electric motorcycle, etc.), power system application (for example, various power generation, road conditioner, smart grid, general household installation type power storage system, etc. Fields), as well as space and deep sea applications (eg, fields such as space probes and submersible research vessels).

400-set battery 400'set battery (conventional)
300 Tightening member 300'Fixing tape (conventional aspect)
301 Ring-shaped band member 301A Ring-shaped band member 301B Approximately ring-shaped band member (corresponding to a binding band type)
302 Inserting member 302A One sandwiching member 302B The other sandwiching member 200 Unit secondary battery laminate 200'Unit secondary battery laminate (conventional)
One main surface of 200α unit secondary battery laminate 200 200β The other main surface of unit secondary battery laminate 200 200γ External surface of unit secondary battery laminate 200 100 unit secondary battery 100'unit secondary battery (conventional) )
100A Side part where the external terminal of the unit secondary battery is arranged 100B Side part facing the side where the external terminal of the unit secondary battery is arranged 100C Side part where the external terminal of the unit secondary battery is not arranged 100C', 100D' unit secondary battery side where the external terminal is not arranged (conventional)
Area proximal to the 100X external terminal installation area 100X'Proximal area to the external terminal installation area (conventional)
Area distal to the 100Y external terminal installation area 100Y'Distal area to the external terminal installation area (conventional)
One main surface of the 100α unit secondary battery laminate 100β The other main surface of the unit secondary battery laminate 100γ External surface of the unit secondary battery laminate 20 External terminal 20'External terminal (conventional)
20A External terminal on the positive electrode side 20A'External terminal on the positive electrode side (conventional)
20B External terminal on the negative electrode side 20B'External terminal on the negative electrode side (conventional)
a ₁ Length of one side 100A where the external terminal 20 is arranged a ₂ Length of side 100C extending in a direction substantially perpendicular to one side 100A

Claims (14)

An assembled battery including a unit secondary battery laminate in which a plurality of unit secondary batteries are stacked.
The assembled battery further includes a tightening member for tightening the unit secondary battery laminate, and the tightening member is viewed from one side of the unit secondary battery in which an external terminal is arranged. An assembled battery that extends to the other side facing one side. The assembled battery according to claim 1, wherein the tightening member extends in a direction substantially parallel to the protruding direction of the external terminal in a plan view. The assembled battery according to claim 1 or 2, wherein one main surface of the unit secondary battery laminate and the other main surface facing the one main surface are sandwiched by the tightening member. The set according to any one of claims 1 to 3, wherein one main surface of the unit secondary battery laminate and the other main surface facing the one main surface are pressed by the tightening member. battery. In a plan view, the external terminal on the positive electrode side and the external terminal on the negative electrode side are arranged on the one side of the unit secondary battery so as to be separated from each other, and the tightening member is provided. The assembled battery according to any one of claims 1 to 4, which is arranged between the external terminal on the positive electrode side and the external terminal on the negative electrode side in a plan view. The assembled battery according to any one of claims 1 to 5, wherein the tightening member is a ring-shaped band member. The assembled battery according to claim 6, wherein the tightening member is an elastic member. The assembled battery according to claim 6 or 7, wherein the tightening member surrounds an outer surface of the unit secondary battery laminate. Any of claims 1 to 5, wherein the tightening member is a sandwiching member that sandwiches the one main surface of the unit secondary battery laminate and the other main surface facing the one main surface. The assembled battery described in Crab. The assembled battery according to any one of claims 1 to 9, wherein the tightening force of the tightening member with respect to the unit secondary battery laminate is 50 N or more and 400 N or less. The assembled battery according to any one of claims 1 to 10, wherein the unit secondary battery has a rectangular shape in a plan view. The unit secondary battery has an aspect ratio of 1.0 or more with respect to the side portion of the one side portion on which the external terminal is arranged, which extends in a direction substantially perpendicular to the one side portion. The assembled battery according to any one of claims 1 to 11. The assembled battery according to any one of claims 1 to 12, wherein each of the positive electrode and the negative electrode of the plurality of unit secondary batteries has a layer capable of occluding and releasing lithium ions. It is a manufacturing method of assembled batteries.
Including a step of laminating a plurality of unit secondary batteries to form a unit secondary battery laminate and a step of tightening the unit secondary battery laminate using a tightening member.
A manufacturing method in which the tightening member extends from one side of the unit secondary battery in which an external terminal is arranged to the other side facing the one side in a plan view.

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