JP5082264B2 - Film-clad electrical device and method for manufacturing the same - Google Patents

Description

  The present invention relates to an electrical device typified by a chemical battery and a capacitor, and particularly relates to a film-clad electrical device in which an electrode laminate is sealed with a packaging material made of a film and a method for producing the same.

  An electric device such as a stacked chemical battery or a capacitor is composed of a metal can, a film, and the like, together with an electrolyte, an electrode stack obtained by alternately stacking a plurality of sheet-like positive electrode bodies and a plurality of negative electrode bodies via separators. It has a configuration that is hermetically sealed (hereinafter simply referred to as “sealing”) with an exterior material. A positive electrode body and a negative electrode body (hereinafter simply referred to as an electrode body when the positive electrode and the negative electrode are not distinguished from each other) have a configuration in which an electrode material is applied to both surfaces of a metal foil. An extending portion, which is a portion where no electrode material is applied, extends from one end portion of the metal foil. The extending portions are collected on the lead portions for external lead-out for each of the positive electrode body and the negative electrode body, and are ultrasonically welded to the lead portions.

  The ultrasonic welding of the extending portion to the lead portion is performed by applying ultrasonic vibration while pressing the lead portion and the plurality of extending portions placed on the anvil with each other by a horn. At this time, the lead portion is placed on the anvil, and the horn is directly pressed onto the uppermost extension portion. The extending part is a part of the metal foil constituting the electrode body, and the thickness thereof is generally as thin as about 10 to 20 μm.

  Therefore, the portion of the extension portion against which the horn is pressed is rubbed by ultrasonic vibration of the horn during ultrasonic welding, and the extension portion may be broken at the edge portion of the horn. Further, when the horn is raised after ultrasonic welding, the region where the horn of the extension portion is pressed is lifted together with the horn, and this may cause the extension portion to be broken. Since the extension portion constitutes a current path between the electrode laminate and the lead portion, if the extension portion is broken, the current flow is hindered. Furthermore, when the electric device is used in an automobile, the extension portion breaks due to vibration while the automobile is running, and in some cases, the extension portion may be broken. Such breakage of the extension portion often occurs in the extension portion where the horn is directly pressed during ultrasonic welding, among the plurality of extension portions stacked on each other.

  Therefore, in order to prevent tearing of the extending portion (metal foil) during ultrasonic welding, Patent Document 1 discloses that a metal foil horn is pressed when ultrasonically welding a plurality of laminated metal foils. It is described that a protective metal plate is provided on the surface to be protected. Patent Document 1 also describes that a protective metal plate having a thickness of 50 μm or more and 200 μm or less is preferable. Thereby, since the horn cannot be directly pressed against the metal foil to be joined, the metal foil is prevented from being broken during ultrasonic welding.

Patent Document 2 does not relate to a technique for joining the lead portion and the extension portion of the battery, but an extremely thin second metal plate such as a metal foil is provided on the first metal plate such as a copper plate. When ultrasonic welding is performed, the second metal plate is folded back into two layers, a horn is pressed against the portion where the second metal plate is stacked, and the first metal plate and the second metal plate are pressed. It is described that the plate is ultrasonically welded. In this way, by folding the second metal plate, the folded portion acts in the same manner as the protective metal plate in Patent Document 1.
JP-A-10-244380 JP-A-9-206963

  As described above, the techniques described in Patent Documents 1 and 2 are effective in preventing breakage of the extension part when ultrasonically welding the lead part and the extension part in the electrical device manufacturing process. It is. However, when these techniques are used when manufacturing a film-clad electrical device in which the electrode laminate to which the lead portion is bonded is sealed with an exterior film, a new problem arises.

  It is considered that the protective metal plate used in Patent Document 1 is actually produced by cutting a large metal plate. Moreover, also in the folding structure used in Patent Document 2, it is considered that the tip of the portion of the metal plate folded back for protection is formed by cutting. Therefore, the edge on the electrode laminate side of the portion of the protective metal plate is sharply formed by cutting. There may be a case where a burr is generated at the edge by cutting.

  On the other hand, a laminate film in which a heat-sealing resin layer and a metal layer are laminated is generally used as an exterior film for sealing an electrode laminate. The electrode laminate is sealed with the laminate film by heat-sealing the laminate film on the outer periphery of the electrode laminate. When the laminate film is heat-sealed, the heat-sealing resin layer of the laminate film is softened not only at the portion to be heat-sealed but also around it.

  Therefore, when the edge of the protective metal plate portion on the electrode laminate side contacts the heat fusion resin layer while the heat fusion resin layer is still softened, the heat fusion resin layer is formed by this edge. It will be hurt. The thickness of the heat-sealing resin layer is reduced at the portion damaged by the edge, and the electrolyte solution is likely to permeate as compared with other portions. Since the exterior film has a metal layer outside the heat-sealing resin layer, the penetration of the electrolytic solution into the heat-sealing resin layer causes an insulation failure. Also, since the protective metal plate portion is ultrasonically welded to the electrode plate extension, the edge of the protective metal plate portion penetrates through the heat-sealing resin layer and reaches the metal layer. Then, an electrode laminated body and an exterior film will short-circuit.

  Note that a single-layer film having only a heat-sealing resin layer can also be used as the exterior film. However, in this case, although insulation failure does not occur, there is a high risk that the electrolyte contained in the battery leaks from scratches caused by the edges of the protective metal plate.

  Therefore, the present invention seals the electrode laminate to which the lead portion is bonded with an exterior film while preventing damage to the extension portion when the extension portion extending from the electrode laminate is ultrasonically welded to the lead portion. An object of the present invention is to provide a film-clad electrical device and a method for producing the same, which can prevent damage to the exterior film.

In order to achieve the above object, the film-covered electrical device of the present invention is electrically connected to an electrical device element extending in a state where a plurality of extending portions made of metal foil are overlapped with each other, and the plurality of extending portions. And an exterior film sealing the electrical device element. The exterior film encloses and surrounds the electric device element from both sides in the thickness direction and is heat-sealed around the outer film, thereby sealing the electric device element by protruding the leads. The film-covered electric device of the present invention further includes at least one sheet portion positioned on the front surface of the extension portion of the uppermost position. Seat, the end surface thereof is had toward the opposite side of the electrical device element side, the bent portion is directed memorial electrical device element side, bent at a plurality of extending portions on, among the plurality of the extending portion top Welded with the extension of the position .

  As described above, by arranging the sheet portion on the outermost surface of the plurality of extending portions, the ultrasonic welding tool is directly pressed against the extending portion made of the metal foil when the plurality of extending portions are joined to each other. This prevents the extension portion from being damaged by the tool. In addition, since the sheet portion is bent so that the end surface faces the side opposite to the electric device element side, when the outer film is heat-sealed to seal the electric device element, the softened outer film The inner surface is prevented from being damaged by the edge of the sheet portion on the electric device element side.

The method for producing a film-clad electrical device of one aspect of the present invention includes a step of preparing an electrical device element extending in a state where a plurality of extending portions made of metal foil are stacked on each other, and a plurality of extending portions on the surface of the extending portion of the uppermost of and have opposite direction end face and the electrical device element side, at least the bent portion countercurrent memorial electrical device element side, bent at a plurality of extending portions on A step of placing one sheet part, a step of welding the uppermost extension part and the sheet part among a plurality of extension parts by pressing a welding tool from above the sheet part, and the extension part and the sheet after the welding and simultaneously or welding of the parts, and the step of electrically connecting the leads for external lead to the extending portion, after welding of the extension portion and the seat portion, the step of sealing the electrical device element in casing films And having. In another aspect of the present invention, a method for producing a film-clad electrical device includes a step of preparing an electrical device element extending in a state in which a plurality of extending portions made of metal foil are stacked on each other, and an extending portion The first folding step of folding the first portion back to the electric device element side at the first position in the middle in the longitudinal direction, and the extension portion folded back to the electric device element side, A second folding step of folding back to the side away from the electrical device element at the position, and after the second folding step, cutting the extended portion including the folded portion at a position farther from the electrical device element than the first position, Forming the sheet portion on the plurality of extending portions, and welding the uppermost extension portion and the sheet portion among the plurality of extending portions by pressing a welding tool from above the sheet portion; and , Extension and sea A step of electrically connecting an external lead to the extension part simultaneously with or after welding with the part, and a step of sealing the electrical device element with an exterior film after welding the extension part and the sheet part And having. The exterior film surrounds and surrounds the electrical device element from both sides in the thickness direction, and heat seals the exterior film around the electrical device element, thereby projecting the leads and sealing the electrical device element.

  The film-clad electrical device of the present invention is manufactured through the above steps.

  In the film-clad electrical device of the present invention, in particular, the step of placing the sheet portion includes a first folding step of folding the extension portion back to the electric device element side at a first position in the longitudinal direction, and to the electric device element side. A second folding step of folding back the extended portion to the side away from the electrical device element at a second position closer to the electrical device element than the first position; and after the second folding step, from the first position And a step of cutting the extended portion including the folded portion at a position away from the electric device element. According to this manufacturing method, a sheet part is formed from a part of extension part. Further, depending on the cutting position, the sheet portion can be formed as a portion continuous with the extending portion.

  According to the present invention, by providing the sheet portion as described above, it is possible to prevent damage to the extending portion by the ultrasonic welding tool during ultrasonic welding between the lead and the extending portion, and Damage to the heat-sealing resin layer of the exterior film at the time of heat-sealing can be prevented. As a result, it is possible to prevent the current flow between the electric device element and the lead from being hindered, and to prevent insulation failure due to damage to the heat-sealing resin layer.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view of a film-clad battery that is an electrical device according to an embodiment of the present invention.

  The film-clad battery 1 shown in FIG. 1 includes an electrode laminate 2 that is an electrical device element having a structure in which a plurality of positive plates and a plurality of negative plates are laminated via a separator impregnated with an electrolytic solution, Two exterior films 4 and 5 for sealing the laminate 2 together with the electrolyte, and the positive electrode plate and the negative electrode plate of the electrode laminate 2 are electrically connected to the exterior films 4 and 5 with their tips extending from the exterior films 4 and 5, respectively. The negative electrode lead 3a and the positive electrode lead 3b are connected.

  Since the exterior films 4 and 5 surround and surround the electrode laminate 2 from both sides in the thickness direction (lamination direction of the positive electrode plate and the negative electrode plate), the exterior films 4 and 5 have a planar dimension larger than the planar dimension of the electrode laminate 2. Yes, the electrode laminate 2 is sealed by heat-sealing the opposing surfaces that overlap each other around the electrode laminate 2. In FIG. 1, the heat-sealed regions of the exterior films 4 and 5 are indicated by hatching as the heat-sealed portion 6. One exterior film 4 has a cup portion 4 a in the central region in order to form a space surrounding the electrode laminate 2. The heat fusion part 6 is formed over the entire circumference of the cup part 4a. The cup portion 4a can be processed by deep drawing. In this embodiment, the cup portion 4a is formed only on one of the exterior films 4, but the cup portions may be formed on both the exterior films 4 and 5, and the exterior film may be formed without forming the cup portions. The electrode laminate 2 may be surrounded by utilizing the flexibility of 4,5.

  As the exterior films 4 and 5, a laminate film can be used. The laminate film constituting the exterior films 4 and 5 may be of any type as long as it has flexibility and can seal the electrode laminate 2 by heat fusion so that the electrolyte does not leak. Absent. As a typical laminate film that can be applied to the present invention, a laminate in which a heat-sealing resin layer made of a heat-fusible resin, a metal layer made of a metal thin film and the like and a protective layer are laminated in this order can be mentioned. Outer films 4 and 5 only need to have at least a heat-sealing resin layer and a metal layer, and a protective layer is provided as necessary. When sealing the electrode laminate 2, the electrode laminate 2 is surrounded by facing the heat-sealing resin layer.

  The metal layer is for giving the exterior films 4 and 5 gas barrier properties. As the metal thin film constituting the metal layer, for example, a foil made of Al, Ti, Ti alloy, Fe, stainless steel, Mg alloy or the like having a thickness of 10 to 100 μm can be used. As the resin constituting the heat-sealing resin layer, for example, polypropylene, polyethylene, these acid-modified products, polyester such as polyphenylene sulfide, polyethylene terephthalate (PET), polyamide, ethylene-vinyl acetate copolymer, and the like can be used. . The thickness of the heat-fusible resin layer is preferably 10 μm to 200 μm, more preferably 30 μm to 100 μm. As the protective layer, polyamide such as nylon, polyester such as PET or polyethylene naphthalate (PEN), and polypropylene can be used.

  Next, the electrode laminate 2 will be described in detail with reference to FIG.

  As shown in FIG. 2, the electrode laminate 2 has a structure in which a plurality of negative plates 11 and a plurality of positive plates 12 are alternately laminated so that the negative plates 11 are located on the uppermost surface and the lowermost surface. .

  The negative electrode plate 11 is a substantially rectangular member in which a negative electrode active material is applied to both surfaces of a metal foil constituting the negative electrode. The negative electrode active material is applied in a rectangular shape to a region excluding one end of the metal foil, whereby the negative electrode plate 11 includes a rectangular negative electrode material application portion 11a applied with the negative electrode active material, and a negative electrode material application. It is divided into an extended portion 11b that extends as it is from one side of the portion 11a and is not coated with anything. The positive electrode plate 12 is also a substantially rectangular member in which a positive electrode active material is applied to both surfaces of a metal foil constituting the positive electrode. The positive electrode active material is applied in a rectangular shape to a region excluding one end of the metal foil, whereby the positive electrode plate 12 has a rectangular positive electrode material application portion 12a to which the positive electrode active material is applied, and a positive electrode material application. It is divided into an extended portion 12b that extends as it is from one side of the portion 12a and is not coated with anything. Since the extending portions 11b and 12b are part of the metal foil, they have conductivity.

  The negative electrode plate 11 and the positive electrode plate 12 are laminated with the extending portions 11b and 12b facing away from each other and the extending portions 11b and 12b extending. The extending portion 11b of the negative electrode plate 11 is collected on the upper surface of the negative electrode lead 3a (see FIG. 1), partially overlaps the negative electrode lead 3a, and is collectively welded by ultrasonic welding. Thus, the negative electrode lead 3a is electrically connected to each negative electrode plate 11. The extending portion 12b of the positive electrode plate 12 is collected on the upper surface of the positive electrode lead 3b (see FIG. 1), partially overlapped with the positive electrode lead 3b, and collectively welded by ultrasonic welding. Thereby, the positive electrode lead 3 a is electrically connected to each positive electrode plate 12. The detailed structure of the joint between the extension and the lead in these positive and negative electrodes will be described later.

  Materials such as the negative electrode plate 11, the positive electrode plate 12, and the electrolytic solution are appropriately selected according to the use of the electrode laminate 2, that is, the type of the film-clad battery 1. The kind of the film-clad battery 1 is not particularly limited, and various chemical batteries such as a lithium ion secondary battery, a nickel hydride battery, a nickel cadmium battery, a lithium metal primary battery or a secondary battery, and a lithium polymer battery can be used. . For example, when the electrode laminate 2 is for a lithium ion secondary battery, the positive electrode plate 12 is made of a positive electrode active material such as lithium-manganese composite oxide or lithium cobaltate, and both surfaces of an aluminum foil having a thickness of 3 to 50 μm. As the negative electrode plate 11, a material obtained by applying a carbon material capable of doping and dedoping lithium to both sides of a copper foil having a thickness of 3 to 50 μm can be used. In this case, an electrolytic solution containing a lithium salt can be used as the electrolytic solution. Further, when an aluminum foil is used for the positive electrode metal foil, an aluminum plate can be used for the positive electrode lead 3b. When a copper foil is used for the negative electrode metal foil, a nickel plate or a copper plate is used for the negative electrode lead 3a. be able to. When the negative electrode lead 3a is formed of a copper plate, the surface thereof may be nickel-plated. Since these materials such as metal foil, active material, and electrolytic solution are used for general lithium ion secondary batteries, detailed description thereof is omitted.

  The separator 13 is disposed between the positive electrode plate 11 and the negative electrode plate 12, and the area thereof is larger than the area of the positive electrode material application part 11a and the area of the negative electrode material application part 12a. As the separator 13, a member that can be impregnated with an electrolytic solution, such as a microporous film (microporous film), a nonwoven fabric, or a woven fabric made of a thermoplastic resin such as polyolefin can be used.

  Here, the structure of the joint portion between the extension portion and the lead described above will be described. The connecting portion between the extension portion and the lead is the same as the structure of the positive electrode and the negative electrode except that the material of each member is different. Therefore, the negative electrode side will be described below as a representative of the positive electrode and the negative electrode.

  FIG. 3 shows a plan view of a joint portion between the electrode laminate 2 and the negative electrode lead 3a. FIG. 4 is a cross-sectional view along the direction in which the extending portion 11b of the negative electrode plate 11 extends during ultrasonic welding of the electrode laminate 2 and the negative electrode lead 3a. In FIG. 3, the position of the exterior film which seals the electrode laminated body 2 is shown with the dashed-dotted line, and the heat-fusion part of the exterior film is shown with the oblique line.

  On the negative electrode side, a plurality of extending portions 11b extend toward the negative electrode lead 3a, and the tips thereof are located on the negative electrode lead 3a. On the negative electrode lead 3a, a plurality of extending portions 11b are overlapped in the thickness direction. At a position where the plurality of extending portions 11b are overlapped, a protective sheet 6 is further disposed on the uppermost extending portion 11b which is the outermost surface.

  The protective sheet 6 faces the electrode laminate 2 side, specifically, the side opposite to the portion where the negative electrode plate 11 and the positive electrode plate 12 are overlapped (hereinafter also referred to as electrode laminate portion), and the bent portion 6a. Is folded in two so as to face the electrode stack. Moreover, as shown in FIG. 3, when the electrode laminated body 2 is sealed with an exterior film, the protective sheet 6 is located in the area | region enclosed by the heat sealing | fusion part of the exterior film. That is, the protective sheet 6 is also sealed with the exterior film together with the electrode laminate 2. As the protective sheet 6, the same metal foil as the metal foil used for the negative electrode plate 11 is preferably used, but other members can be used as long as they can be ultrasonically welded to the extending portion 11 b.

  Ultrasonic welding of the extending part 11b and the negative electrode lead 3a can be performed as follows. First, a negative electrode plate 11 and a positive electrode plate 12 are laminated via a separator 13, and an electrode laminate 2 having extending portions 11 b and 12 b extending from the negative electrode plate 11 and the positive electrode plate 12 is prepared. At this stage, the extending portions 11b and 12b are overlapped with each other on the positive electrode side and the negative electrode side, but are not joined. Next, the negative electrode lead 3a is placed on the anvil 9b, and a plurality of extending portions 11b are placed thereon. Further, the protective sheet 6 is placed thereon with the bent portion 6a facing the electrode laminated portion. In this state, a horn 9a, which is a tool for ultrasonic welding, is pressed from above the protective sheet 6 to apply ultrasonic vibration. As a result, the negative electrode lead 3a, the plurality of extending portions 11b, and the protective sheet 6 are welded together. That is, the protective sheet 6 is disposed at a position facing the negative electrode lead 3a across the plurality of extending portions 11b at the joint portion between the plurality of extending portions 11b and the negative electrode lead 3a, and the negative electrode lead 3a and the plurality of negative electrode leads 3a. It is welded with the extension part 11b.

  In the present embodiment, the horn 9a has a plurality of convex portions that are spaced apart from each other along the width direction of the extending portion 11b, and these convex portions are pressed against the protective sheet 6. . Therefore, in this embodiment, a welding mark 7 is formed at a position where the convex portion of the horn 9a is pressed at the joint portion between the extending portion 11b and the negative electrode lead 3a as shown in FIG. The welding marks 7 are formed at intervals from each other along the width direction of the extending portion 11b corresponding to the convex portion of the horn 9a. In addition, since the electrode laminate 2 is simply formed by laminating the negative electrode plate 11, the positive electrode plate 12, and the separator 13, the laminated state is fixed with a fixture such as a clip or a tape so that mutual positional deviation does not occur. It is preferable to use and hold.

  While the ultrasonic vibration is applied by the horn 9a, the protective sheet 6 may be broken by the ultrasonically vibrating horn 9a. Further, when the horn 9a is lifted after ultrasonic welding, the area of the protective sheet 6 where the horn 9a is pressed is lifted together with the horn 9a, and the protective sheet 6 may be broken. However, the protective sheet 6 is not a part that constitutes a current path between the electrode laminate 2 and the negative electrode lead 3a, and even if a tear occurs, it has an influence on the electrical characteristics of the film-covered battery 1. It is not a thing.

  As described above, the connection between the lead on the negative electrode side and the extension portion has been described. As with the negative electrode side, the extension on the uppermost position of the plurality of extension portions 12b placed on the positive electrode lead 3b is also described on the positive electrode side. The protective sheet 6 is placed on the protruding portion 12b, and ultrasonic welding is performed in this state. The effect of this protective sheet 6 is the same as that on the negative electrode side.

  The electrode laminate 2 to which the negative electrode lead 3a and the positive electrode lead 3b are connected as described above is then sealed with the exterior films 4 and 5 together with the electrolytic solution.

  The electrode stack 2 can be sealed as follows.

  First, the electrode laminate 2 to which the negative electrode lead 3a and the positive electrode lead 3b are connected is sandwiched between the two outer films 4 and 5 so that the negative electrode lead 3a and the positive electrode lead 3b extend from the outer films 4 and 5. The three sides around the exterior films 4 and 5 are heat-sealed. At this time, when the fixture that holds the laminated state of the electrode laminate 2 is a clip, the clip is removed before heat-sealing the exterior films 4 and 5. If the fixture is a tape, the tape may be left attached. Thereafter, an electrolytic solution is injected from the remaining one side that is not heat-sealed, and impregnated in the electrode laminate 2. The assembly in which the electrode laminate 2 is impregnated with the electrolytic solution is placed in a vacuum chamber, and the remaining one side of the exterior films 4 and 5 is heat-sealed in a reduced pressure atmosphere. Thereby, the electrode laminate 2 is sealed.

  After the remaining one side of the exterior films 4 and 5 is heat-sealed, when the inside of the vacuum chamber is returned to atmospheric pressure, the exterior films 4 and 5 are brought into close contact with the electrode laminate 2 due to atmospheric pressure. The film-clad battery 1 in which the position of the electrode laminate 2 within 5 is fixed is produced.

  Here, an example in which the electrode laminate 2 is sealed in a reduced-pressure atmosphere has been described, but this step may be performed in an atmospheric pressure. Moreover, although the example using the two exterior films 4 and 5 as an exterior material was shown, you may fold one exterior film in half and pinch | interpose the electrode laminated body 2. FIG.

  During the heat sealing of the exterior films 4 and 5, the heat sealing resin layer of the exterior films 4 and 5 is softened not only at the part to be heat-sealed but also at the periphery, for example, the part facing the protective sheet 6. The sharp parts of the other members are in a state of being easily damaged by contact. The protective sheet 6 is located on the extended portions 11b and 12b, and in particular, the edge on the electrode laminated portion side is easily in contact with the heat-sealing resin layer. However, the edge of the protective sheet 6 on the electrode laminated portion side is a bent portion 6a, and there is no sharp portion formed by cutting.

  Therefore, even if the heat-sealing resin layer comes into contact with the protective sheet 6 during the heat-sealing of the exterior films 4 and 5, it is possible to prevent the heat-sealing resin layer from being damaged. As a result, it is possible to prevent problems caused by the electrolyte solution soaking into the heat sealing resin layer and problems caused by the edge of the protective sheet 6 penetrating the heat sealing resin layer.

  As described above, the protective sheet 6 is preferably made of a metal foil. Most preferably, the protective sheet 6 on the negative electrode side is made of the same metal foil as the metal foil constituting the negative electrode plate 11, and the protective sheet 6 on the positive electrode side is made of the same metal foil as the metal foil constituting the positive electrode plate 12. Is to configure. In this case, the production of the protective sheet 6 and the arrangement on the extending portions 11b and 12b can be easily performed. This will be described below with reference to FIG. Although FIG. 5 illustrates the negative electrode side, the positive electrode side is the same as the following description replaced with the positive electrode, and therefore the description of the positive electrode side is omitted.

  FIG. 5 shows a cross-sectional view at a stage after the negative electrode plate 11 and the positive electrode plate 12 are laminated via the separator 13 and before the extended portion 11b is cut to a predetermined length. As shown in FIG. 5, the plurality of extending portions 11 b each extending from the electrode stack portion and made of a metal foil each have a length longer than a predetermined size, and are placed on the support base 21. The extension portion 11b at the uppermost position among the plurality of extension portions 11b is folded back to the electrode laminate portion side at the intermediate position in the longitudinal direction, and is then positioned on the electrode laminate portion side from the first turn-up position F1 (first position). 2 is folded back to the side away from the electrode stacking portion to form a zigzag shape. As a result, the extension portion 11b at the uppermost position is tripled between the first folding position F1 and the second folding position F2.

  The plurality of extending portions 11b overlapping in this state are cut by a cutter (not shown) and trimmed to a predetermined length. At this time, the plurality of extending portions 11b are cut at the cutting position A between the first folding position F1 and the second folding position F2, including the folded portion. At this position, the uppermost extension 11b is tripled, so the uppermost extension 11b is divided into a portion extending from the electrode stack and another three small pieces. Of the three divided pieces, the small piece located closer to the electrode laminate portion than the cutting position A is a metal foil that is folded in half with a folded portion on the electrode laminate portion side. The portion of the metal foil becomes the protective sheet 6 shown in FIG.

  Thus, by forming the protective sheet 6 using the bending of the extension portion 11b at the uppermost position, it is not necessary to prepare the protective sheet 6 separately, and the separately prepared protective sheet 6 is divided into a plurality of extension portions 11b. There is no need to handle on the overlapping parts. As a result, it is possible to simplify the joining process between the extending portion 11b and the negative electrode lead 3a, and thus the manufacturing process of the film-clad battery 1.

  Further, when the protective sheet 6 is formed as described above, burrs may occur on the cut surface of the protective sheet 6 at the cutting position A. Even in this case, the burr 6b on the cut surface of the protective sheet 6 can be obtained by cutting toward the support base 21 from above the plurality of extending portions 11b stacked on the support base 21 as shown in FIG. , Formed on the lower edge. Since the negative electrode lead 3a exists on the side where the burr 6b extends when the outer film is heat-sealed, the burr 6b may contact the heat-fusing resin layer of the outer film and damage the heat-fusing resin layer. Absent.

  On the other hand, in FIG. 5, when the plurality of overlapping extending portions 11b are cut to a predetermined length, the plurality of extending portions are cut at the cutting position B, which is a position farther from the electrode stacking portion than the first folding position F1. The protruding portion 11b may be cut including the folded portion. In this case, since the protective sheet is formed continuously with the extending portion 11b, the protective sheet is formed during handling of the electrode laminate 2 after the extending portion 11b is cut and joined to the negative electrode lead 3a. It can be prevented from falling off.

  In the embodiment described above, an example in which one protective sheet 6 is used has been described. However, it is possible to more reliably prevent the extension portion from being broken during ultrasonic welding between the extension portion of the electrode plate and the lead for external lead-out. In order to do so, a plurality of protective sheets 6 can be used. An example is shown in FIGS. 7 and 8, the negative electrode side will be described. However, the positive electrode side is the same as the following description replaced with the positive electrode, and therefore the description of the positive electrode side is omitted.

  The example shown in FIG. 7 is an example in which two protective sheets 6 are nested. Further, the example shown in FIG. 8 is an example in which two folded protective sheets 6 are simply overlapped. Also in these examples, the protective sheet 6 may be a separate member from the extending portion 11b, or may be formed from a part of the extending portion 11b by using the return of the extending portion 11b. .

  When the protective sheet 6 is a separate member from the extending portion 11b, the configuration shown in FIG. 7 is such that two protective sheets 6 that have been cut in advance to a predetermined size are stacked, and two protective sheets are in that state. It can be formed by folding the sheets together. Further, the configuration shown in FIG. 8 can be formed by stacking two protective sheets 6 folded in advance one by one. In any example, the protective sheet 6 is disposed with the bent portion facing the electrode laminated portion side and is ultrasonically welded together with the other extending portion 11b.

  On the other hand, when the protective sheet 6 is formed from a part of the extension part 11b, the configuration shown in FIG. 7 is not only the uppermost extension part 11b in FIG. 5, but also the extension part 11b directly below the zigzag shape. It can be formed by folding back and cutting an unnecessary tip portion. When cutting the extending portion 11b, the structure shown in FIG. 7 can be obtained by cutting at the cutting position A shown in FIG. If it cut | disconnects at the cutting position B, the protection sheet 6 continuous with the extension part 11b will be formed. Further, the configuration shown in FIG. 8 is formed by further repeating the folding of the uppermost extension portion 11b between the folding position F1 and the folding position F2 in FIG. 5 and cutting unnecessary tip portions. be able to. Also in this example, when the extension portion 1b is cut, the configuration shown in FIG. 8 can be obtained by cutting at the cutting position A shown in FIG. If it cut | disconnects at the cutting position B, the protection sheet 6 continuous with the extension part 11b will be formed.

  7 and 8 show an example having two protective sheets 6, three or more sheets may be used. Moreover, when forming the protection sheet 6 using the folding | returning of the extension part 11b, depending on the number of the extension parts 11b, ie, the number of the electrode plates in an electrode laminated body, all the extension parts 11b are folded up collectively. A plurality of protective sheets may be formed.

  The present invention has been described above with some typical examples. However, the present invention is not limited to these examples, and can be appropriately changed within the scope of the technical idea of the present invention.

  For example, in the above-described example, the extension portion and the sheet portion are joined to the lead by ultrasonic welding, but joining by resistance welding or laser welding is also included in the present invention. Even with these resistance welding and laser welding, a welding mark is formed by a tool at the welding point, and the metal foil may be broken along the boundary of the welding mark or radially extending from the boundary of the welding mark. . According to the present invention, even if such a metal foil breaks, this breakage occurs in the sheet portion, and therefore does not affect the electrical characteristics of the film-covered electrical device. Note that, among these various joining methods, ultrasonic welding is likely to cause the metal foil to break, and the effects of the present invention can be exhibited most.

  The electrical connection between the lead and the electric device element can be performed by dividing the lead, the extension portion, and the sheet portion into a plurality of steps instead of joining them together. For example, first, a plurality of extending portions are bonded to each other for each of the positive electrode and the negative electrode. Next, the positive electrode and negative electrode extension portions integrated by bonding are electrically connected to the positive electrode and negative electrode leads, respectively. In this case, at the time of joining the extension parts, a protective sheet part is further placed on the extension part at the uppermost position, and each extension part and the sheet part are joined together. The joining method such as the ultrasonic welding described above is used for joining the extension part and the sheet part. The electrical connection between the extension part and the lead is not limited to a joining method such as ultrasonic welding, but is also an arbitrary method generally used to electrically connect a plurality of electrical components, such as a method using mechanical crimping such as caulking. This method can be used.

  The lead may be composed of a plurality of members such as an inner lead and an outer lead. In this case, the inner lead is electrically connected to the extending portion of the electric device element, and then the inner lead and the outer lead are electrically connected, or vice versa. An electrical connection with the device element can be made. After the electrical device element is sealed with the exterior film, only the outer leads protrude from the exterior film.

  The connection between the extension part and the inner lead may be performed simultaneously with the joining between the sheet part and the extension part, or may be made after the joining between the extension part and the sheet part. For the electrical connection between the extension part and the inner lead and the electrical connection between the inner lead and the outer lead, the same method as the electrical connection method between the lead and the extension part described above can be used.

  In a strict sense, it can be considered that only a member protruding from the exterior film is a lead, in other words, a terminal for external connection. When thinking in this way, said structure can also be considered that the lead | read | reed and the extension part are electrically connected via the intermediate member.

  Moreover, in the example mentioned above, although the laminate film was shown as an exterior film, you may seal an electric device element using the exterior film which has only a heat sealing | fusion resin layer. According to the present invention, since the exterior film is hardly damaged when the exterior film is heat-sealed, even when a single-layer film having only the heat-sealing resin layer is used as the exterior film, It can seal well.

  Furthermore, in the above-described example, the chemical battery is taken as an example. However, the present invention is an electrode laminate that stores electric energy inside, such as a capacitor element exemplified by a capacitor such as an electric double layer capacitor or an electrolytic capacitor. Can be applied to an electrical device sealed with an exterior material.

It is a disassembled perspective view of the film-clad battery which is an electric device by one Embodiment of this invention. It is a disassembled perspective view of the electrode laminated body shown in FIG. It is a top view of the junction part of the electrode laminated body shown in FIG. 1, and a negative electrode lead. It is sectional drawing along the direction where the extension part of a negative electrode plate is extended at the time of the ultrasonic welding of an electrode laminated body and a negative electrode lead. It is sectional drawing before a cutting | disconnection of the extension part of a negative electrode plate. It is an expanded sectional view of the protection sheet formed by cut | disconnecting in the cutting position A of FIG. It is sectional drawing of the junction part of an electrode laminated body and a negative electrode lead which shows the other example of the protective sheet used for this invention. It is sectional drawing of the junction part of an electrode laminated body and a negative electrode lead which shows the further another example of the sheet | seat for protection used for this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film exterior battery 2 Electrode laminated body 3a Negative electrode lead 3b Positive electrode lead 4,5 Exterior film 11 Negative electrode plate 11b, 12b Extension part 12 Positive electrode plate 13 Separator 6 Protective sheet

Claims (10)

An electrical device element extending in a state where a plurality of extending portions made of metal foil are overlapped with each other;
A lead electrically connected to the plurality of extending portions;
An exterior film that encloses the electric device element from both sides in the thickness direction and is heat-sealed around the electric device element to seal the electric device element by projecting the leads; and
At least one sheet portion disposed on the surface of the uppermost extension portion among the plurality of extension portions;
Have
The seat portion has an end face that is had toward the opposite side of the electrical device element side, the bent portion is directed memorial said electrical device element side, bent at a plurality of extending portions on the plurality of extension It is welded to the uppermost extension part of the extension part ,
Film exterior electrical device.   The film-covered electrical device according to claim 1, wherein the plurality of sheet portions are arranged to overlap each other.   The film-covered electrical device according to claim 2, wherein the plurality of sheet portions are stacked in a nested manner. The film-covered electrical device according to any one of claims 1 to 3, wherein the sheet portion is made of the same member as the extension portion to which the sheet portion is welded . The film-covered electrical device according to claim 4, wherein the sheet portion is a portion further extending from at least one of the extending portions to which the sheet portion is welded . The welding of the at least the extension portion the seat portion being made by ultrasonic welding, the film covered electric device according to any one of claims 1 to 5.   The said exterior film is a laminate film in which at least a metal layer and a heat sealing resin layer are laminated, and surrounds the electrical device element with the heat sealing resin layer as an inner surface. The film-covered electrical device according to claim 1. Preparing an electrical device element extending in a state where a plurality of extending portions made of metal foil are stacked on each other;
On the surface of the extending portion of the uppermost one of the plurality of extension portions, the opposite end faces and said electrical device element side have countercurrent, the bent portion is directed memorial said electrical device element side, said plurality of Placing at least one sheet part folded on the extension part;
Welding the uppermost extension portion and the sheet portion of the plurality of extension portions by pressing a welding tool from above the sheet portion; and
After welding simultaneously or welding between the sheet portion and the extending portion, and the step of electrically connecting the leads for external lead to the extending portion,
After welding the extension part and the sheet part, the electric device element is surrounded and surrounded by an outer film from both sides in the thickness direction, and the outer film is heat-sealed around the electric device element. Sealing the electrical device element;
The manufacturing method of the film-clad electrical device which has this. Preparing an electrical device element extending in a state where a plurality of extending portions made of metal foil are stacked on each other;
A first folding step of folding the extending portion back to the electrical device element side at a first position in the middle in the longitudinal direction;
A second folding step of folding the extension portion folded back to the electrical device element side at a second position closer to the electrical device element than the first position toward the side away from the electrical device element;
After the second folding step, the extending portion is cut including the folded portion at a position farther from the electrical device element than the first position, and a sheet portion is formed on the plurality of extending portions. Process,
Welding the uppermost extension portion and the sheet portion of the plurality of extension portions by pressing a welding tool from above the sheet portion; and
Electrically connecting a lead for external drawing to the extension part simultaneously with or after welding of the extension part and the sheet part;
After welding the extension part and the sheet part, the electric device element is surrounded and surrounded by an outer film from both sides in the thickness direction, and the outer film is heat-sealed around the electric device element. Sealing the electrical device element;
Off Irumu manufacturing method of the exterior electrical devices that have a. Wherein the step of welding comprises welding by ultrasonic welding, a manufacturing method for a film-covered electrical device according to claim 8 or 9.

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