JP2003249423A - Storage element and manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storage element for reducing a width of a marginal part of a winding electrode sheet extruded from a separator and to provide its manufacturing method. <P>SOLUTION: The storage element 1 includes an electrode body 10, in which a positive electrode sheet 12 and a negative electrode sheet 14 are wound in a flat shape sandwiching a separator. Each end of the electrode body 10 in an axial direction is formed with the positive electrode sheet 12 or the negative electrode sheet 14, and these are separated in the thickness direction with a boundary of an inner winding circumferential part of the electrode body 10, while a sheet connection part 42 of a collector bar is inserted therein. Each separated electrode sheet 12 or 14 is collected from both the outer circumferential part and the inner circumferential part of the electrode body 10 to the central part. The collected part is welded to two connection faces 45a included in the sheet connection part 42. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a storage element and a method for manufacturing the same. In addition, in the present specification, the “electric storage element” is a concept including both a battery (lithium ion battery, nickel hydrogen battery, etc.) and a capacitor (electric double layer capacitor, etc.).

[0002]

2. Description of the Related Art There is known an electricity storage device including an electrode body in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween. In many of such power storage elements, the positive electrode sheet and the negative electrode sheet protruding from both sides of the separator form one end and the other end in the axial direction of the electrode body. The main method of connecting the electrode body and the terminal in the electricity storage device including such an electrode body is as follows: (1). An electrode sheet in which a large number of current collecting tabs are welded at the side end (the portion protruding from the separator) is used. A method of winding to make an electrode body, collecting the current collecting tabs and connecting to the terminals, (2). From the outer peripheral side of the electrode body to the inner peripheral side (from the radial outer side There is a method in which the electrode sheets are gathered together by compression (to the center side) and the terminals are connected to the gathered portions. In general,
The method (2) above has higher productivity than the method (1) above, and is also advantageous in terms of downsizing of the electricity storage device.

FIG. 13 is a schematic diagram showing an example of a structure in which a collector terminal 140 is connected to the positive electrode side of a flatly wound electrode body (flat type electrode body) 10 by applying the method (2) above. FIG. In FIG. 13, reference numeral 12 is a positive electrode sheet,
Reference numeral 14 indicates a negative electrode sheet, and reference numeral 16 indicates a separator. In addition, an active material layer (not shown) is formed on each of the positive electrode sheet 12 and the negative electrode sheet 14 in the portion laminated with the separator 16. The positive electrode sheets 12 forming the axial end portion of the electrode body 10 are gathered from both sides in the thickness direction of the electrode body 10 (left and right direction in FIG. 13) at a substantially central portion thereof. A collector terminal 140 is connected to the positive electrode sheets 12 collected in this manner by welding or the like. In addition, the code | symbol C in FIG. 13 has shown the center part of the thickness direction of the flat type electrode body 10.

[0004]

However, in such a current collecting structure, if an attempt is made to connect the current collecting terminal 140 also to the positive electrode sheet 12 in the portion located on the outer peripheral side (left and right ends in FIG. 13) of the electrode body 10, Separator 16 of the positive electrode sheet 12
The portion protruding from the positive electrode sheet 12 (collecting terminal 140
The portion for connecting to the above, where the active material layer is not formed; hereinafter also referred to as "collector terminal connecting portion". ) Becomes wider. Since the portion where the active material layer is not formed (collector terminal connecting portion) does not contribute to the electrode reaction, its width can be reduced from the viewpoint of improving the capacity per volume (mounting efficiency) of the electricity storage element. preferable.

Japanese Patent Laid-Open No. 2000-223109 discloses that
A technique is disclosed in which a current collector (collector terminal) is formed by repeatedly bending a metal plate into a corrugated plate shape, and a large number of electrode sheets are sandwiched between the corrugated plate-shaped gaps and pressed from both sides for welding. ing. However, in this technique, the operation of sandwiching the electrode sheet in each corrugated plate-shaped gap is complicated, and it is difficult to reliably weld the current collector and the electrode sheet. As described above, the technique described in the above publication has room for further improvement in productivity (particularly, workability in arranging the current collecting terminal and in connecting the current collecting terminal and the electrode sheet). .

An object of the present invention is to provide an electricity storage device capable of reducing a width of a portion of an electrode sheet which is protruded from a separator and wound, and a manufacturing method thereof.

[0007]

Means for Solving the Problems, Actions and Effects The present inventor has described above by gathering the electrode sheets protruding from the separator from both the outer peripheral side and the inner peripheral side of the spirally wound electrode body between them. We found that we could solve the problem.

The electricity storage device provided by the present invention comprises an electrode body in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween, and a collector terminal connected to the axial end portion of the electrode body. Prepare A sheet connecting portion having a plurality of connecting surfaces is formed on the collector terminal. The sheet connecting portion is inserted from the axial end portion of the electrode body to the winding inner peripheral portion of the electrode body. The positive or negative electrode sheet that constitutes the axial end portion of the electrode body has a plurality of locations in the circumferential direction of the electrode body from both the outer circumference side and the inner circumference side between them (the outer circumference and the inner circumference of the electrode body Between). Each of the gathered portions (electrode sheets) is connected to each of the plurality of connection surfaces. Here, the outer circumference and the inner circumference of the electrode body refer to the outer circumference and the inner circumference of a portion of the electrode body that is wound with the separator. In the electricity storage device having such a configuration, as compared with the configuration in which the electrode sheets are gathered together in one direction from the outer peripheral side to the inner peripheral side of the electrode body (see FIG. 13), the portion of the electrode sheet that is extended from the separator and is wound (collected) The width of the electric terminal connection portion) can be reduced. Therefore, the mounting efficiency of the storage element can be improved.

The present invention is preferably applied to a power storage element having an electrode body wound in a flat shape. It is preferable that the seat connecting portion provided in this power storage element has two connecting surfaces. It is preferable that the two connection surfaces face outward in the thickness direction of the flat electrode body (that is, the short side direction in the cross section of the electrode body). In the electricity storage device having such a configuration, the axial end portion of the electrode body is moved from the inner circumference side to the outer circumference side by the connection surface of the sheet connection portion inserted in the winding inner circumference portion (center portion in the thickness direction) of the flat electrode body. It is spread to the side. As a result, the electrode sheets are gathered from the inner peripheral side to the outer peripheral side of the electrode body on the connection surface of the sheet connecting portion. Further, by compressing the electrode body from both sides in the thickness direction, the electrode sheet is formed on the connection surface of the sheet connection portion,
The electrode bodies are gathered from the outer peripheral side to the inner peripheral side. Thus, the current collecting structure (connection structure between the electrode body and the current collecting terminal) of the present invention in which the electrode sheets are gathered from both the outer peripheral side and the inner peripheral side of the electrode body can be easily realized. it can.

An example of a preferable current collecting terminal provided in such a power storage element is one in which the sheet connecting portion has a flat plate shape facing the thickness direction of the electrode body. The electrode sheet has a flat plate (sheet connection part) front surface and back surface (two connection surfaces)
It is preferable that they are gathered together and connected. Such a collector terminal can be easily manufactured from, for example, a single metal plate because the sheet connecting portion has a simple shape.

As another preferred current collecting terminal, the sheet connecting portion has a bent plate shape, and a bent portion forms a portion biased to one side in the thickness direction of the electrode body and a portion biased to the other side. The thing is illustrated. It is preferable that the electrode sheets are gathered and connected to the surfaces (two connection surfaces) on the projecting side of the portion biased to one side and the portion biased to the other side, respectively. The collector terminal having such a shape can be easily manufactured, for example, by bending a single metal plate.

Still another preferable current collecting terminal is one in which the sheet connecting portion is plate-shaped, and both end faces in the width direction of the plate face the thickness direction of the electrode body. It is preferable that the electrode sheets are gathered and connected to their side end faces (two connection faces). Such a collector terminal can be easily manufactured from, for example, a single metal plate because the sheet connecting portion has a simple shape.

When the electricity storage device of the present invention is provided with a flat electrode body, the preferable distance between the two connecting surfaces of the sheet connecting portion of the collector terminal connected to the flat electrode body is preferably that of the flat electrode body. It is almost half the thickness. The "distance between two connection surfaces" means the distance between both connection surfaces in the thickness direction of the electrode body. More specifically, it refers to the average distance between the portions of the two connection surfaces to which the electrode sheets are connected. Here, "substantially half" means, for example, as shown in FIG. 5, when the thickness of the flat electrode body is H, the distance h1 between both connecting surfaces is h1.
Is larger than 0.25H and smaller than 0.75H. More preferably, this interval is in the range of 0.4H to 0.6H. In addition, the distance between the two connecting surfaces is set so that the distance h2 between the central positions of the thicknesses of the electrode sheets gathered on these connecting surfaces can be approximately 0.5H (for example, in the range of 0.4H to 0.6H). Is preferably set. According to the current collecting terminal having such a shape, the current collecting structure of the present invention in which the electrode sheets are gathered between the outer circumference and the inner circumference of the electrode body can be easily realized. In particular, the central position between both connection surfaces and the central position in the thickness direction of the electrode body are substantially coincident (for example, the deviation between the two is 0.4H to
In the range of 0.6H), the effect of reducing the width of the collector terminal connecting portion is great, which is preferable.

The portion of the electrode sheet forming the axial end portion of the electrode body, which is not connected to the connection surface, may or may not be gathered together. There is no particular limitation on how to collect the items when they are collected. For example, they may be gathered from both the outer peripheral side and the inner peripheral side of the electrode body, may be gathered from the outer peripheral side to the inner peripheral side, or may be gathered from the inner peripheral side to the outer peripheral side. Good. The gathered positions may be between the outer circumference and the inner circumference of the electrode body, or may be further inside (the winding inner circumference portion) than the inner circumference of the electrode body. It is preferable that the electrode bodies are gathered more inward than the outer periphery.

In a preferred one of the electric storage devices of the present invention, a space opened at the end face of the electrode body (end face with respect to the winding axis direction) on the back side of the portion where the gathered electrode sheets are connected to the connection face. Are formed. The electricity storage device having such a configuration has connectivity (workability and / or connection reliability) when connecting the electrode sheets gathered on each connection surface.
Is good. For example, ultrasonic welding can be performed by inserting an anvil from the end surface of the electrode body into this space (the back surface of the portion to which the electrode sheet is connected).

In another preferred storage element of the present invention, between the plurality of connecting surfaces of the sheet connecting portion,
A space is formed on the end face of the electrode body (the end face with respect to the winding axis direction). The current collector terminal including the sheet connecting portion having such a shape is more suitable for an electrode sheet than a current collector terminal having a shape having no space between the connection surfaces (for example, a current collector terminal having a solid space between the connection surfaces). Has good connectivity. For example, ultrasonic welding can be performed by inserting an anvil from the end surface of the electrode body into this space (between the connection surfaces).

One of the storage elements of the present invention is an electrode body,
A power storage element container containing the current collection terminal and the electrolytic solution, and an external terminal having one end electrically connected to the current collection terminal and the other end exposed (preferably protruding) to the outside of the power storage element container. It can be configured to further include. Here, it is preferable that the current collector terminal and the external terminal are connected directly or via another rigid metal member (that is, not via a lead made of a metal foil or a metal wire).
In this case, the conductive path between the electrode body and the external terminal is likely to have a relatively large cross-sectional area. Thereby, the internal resistance of the storage element can be suppressed low. Moreover, the dimensions between the electrode body and the external terminals are easily determined, and the assembly is easy.

Further, according to the present invention, there is provided a method of manufacturing a power storage device having a flat electrode body. This method comprises a step of preparing a current collector terminal in which a sheet connecting portion having two connecting surfaces is formed, and a step of producing a tubular electrode body in which a positive electrode sheet and a negative electrode sheet are wound via a separator. , The step of inserting the sheet connecting portion from the axial end of the tubular electrode body to the winding inner peripheral portion, the step of crushing the tubular electrode body to form a flat shape, and the axial end of the electrode body The process includes a step of gathering positive or negative electrode sheets forming a part on the two connecting surfaces of the sheet connecting portion, and a step of connecting the gathered electrode sheets to the connecting surface. Here, the step of crushing the tubular electrode body and the step of gathering the electrode sheets on the connection surface may be performed at the same time. According to such a manufacturing method, since the sheet connecting portion is inserted into the winding inner peripheral portion (hollow portion) of the tubular electrode body and the electrode body is crushed into a flat shape, the operation of inserting the sheet connecting portion is easy. is there.

The step of connecting the electrode sheet to the connecting surface can be carried out by various welding methods such as ultrasonic welding, resistance welding and laser welding. Of these, it is particularly preferable to use the ultrasonic welding method.

As a preferred mode of performing the ultrasonic welding method, an anvil is inserted on the back side of the connection surface, and the connection surface and the electrode sheet gathered on the connection surface are inserted between the anvil and the horn. An example is shown in which they are sandwiched. In this mode, for example, the current collecting terminal is arranged so that a space opening to the end face of the electrode body is formed on the back side of each connection surface, and the anvil is inserted into this space from the axial end portion of the electrode body. It can be carried out. In another preferred embodiment, an anvil is inserted between the two connecting surfaces, and one of the connecting surfaces and the electrode sheet gathered on the connecting surface are sandwiched between the anvil and the horn and welded. Aspects are illustrated. In this aspect, for example, the current collector terminal is arranged so that a space opening at the end face of the electrode body is formed between the two connection surfaces, and the anvil is inserted into this space from the axial end portion of the electrode body. It can be carried out.

The power storage element of the present invention or the manufacturing method of the present invention can be applied to various power storage elements having a wound electrode. For example, it can be applied to both batteries and capacitors, and the type of electrolyte may be either aqueous or non-aqueous, and its composition is not limited. Examples of the types of power storage elements to which the present invention is preferably applied include electric double layer capacitors and lithium ion batteries.

Further, as an electric storage element to which the present invention is particularly effective, various electric storage elements (preferably electric double layer capacitors) provided with an electrode body having a relatively large gap (winding thickness) between the inner circumference and the outer circumference. Or a lithium ion battery). For example, in the case of an electrode body having a winding thickness T (see FIG. 5) of 1 cm or more (typically 1 to 5 cm) or a flat type electrode body, the thickness H (see FIG. 5) in the cross section is 2 cm. It is preferably applied to an electricity storage device provided with an electrode body having the above size (typically 2 to 10 cm). In addition, a great effect can be obtained by applying the present invention to various electric storage devices including an electrode body in which the number of windings of the electrode sheet is relatively large. For example, the number of windings is 15
Or more (typically 15 to 120), more preferably 20
It is preferably applied to an electricity storage device provided with the electrode body as described above (typically 20 to 100).

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is also characterized by being embodied in the following modes.

(Mode 1) The electrode sheets forming the axial end portions of the electrode body are gathered together in the central portion of the outer circumference and the inner circumference of the electrode body (that is, the central portion of the winding thickness of the electrode body). . Here, as shown in FIG. 5, the “central portion” has the winding thickness of the electrode body 10 as T, and the electrode sheets gathered together in the winding thickness direction (here, the positive electrode sheet 1).
2) is approximately 0.5T (for example, 0.4T to 0.
6T range). According to this configuration,
The effect of reducing the width of the collector terminal connecting portion (the effect of improving the mounting efficiency of the electricity storage element) is great.

(Mode 2) The connection surface of the collector terminal and the connection portion of the electrode sheet are provided at substantially equal intervals in the circumferential direction of the electrode body. With such a configuration, current can be collected relatively uniformly from the entire electrode body. This can reduce the internal resistance of the storage element. The preferred number of connection points is 2 in the case of a flat electrode body.
And 2 to 6 in the case of a cylindrical electrode body. Also,
It is preferable that the number of connection points is an even number, and that the connection points are provided at mutually opposing positions. In this case, the operation of collecting the electrode sheets on the connection surface and / or the operation of connecting the collected electrode sheets to the connection surface is easy.

(Mode 3) An electric storage device in which an electrode body is wound in a flat shape, a sheet connecting portion has two connecting surfaces, and the two connecting surfaces face outward in the thickness direction of the flat electrode body. In the element, these connection surfaces are arranged at the respective central portions in the long side direction (typically, the direction orthogonal to the thickness direction of the electrode body) in the cross section of the flat electrode body. In such a configuration, after connecting the electrode sheet to one of the connection surfaces (for example, welding, preferably ultrasonic welding), if the electrode body is half-turned around its winding axis, one of the electrode sheets is turned before the half-turn. The other connecting surface is arranged at substantially the same position as where the connecting surface was. Therefore, workability in sequentially connecting the electrode sheets to the one connection surface and the other connection surface is good.

(Mode 4) An electric storage device in which an electrode body is wound in a flat shape, a sheet connecting portion has two connecting surfaces, and the two connecting surfaces face outward in the thickness direction of the flat electrode body. In the element, these connection surfaces are arranged so that their positions are displaced from each other (that is, the connection surfaces do not face each other) with respect to the long side direction in the cross section of the flat electrode body. Such a configuration is suitable for a manufacturing method in which electrode sheets are simultaneously connected (ultrasonic welding) to one connection surface and the other connection surface.

(Mode 5) The electrode body is wound in a flat shape, and the current collecting terminal has a lead-out portion extending along the end face of the electrode body in the direction of the long side in the cross section of the flat electrode body. And a sheet connecting portion formed following one end of the portion. The sheet connecting portion has a support portion that enters into the interior of the electrode body from the end surface thereof, and two blade portions that extend inside the electrode body from both ends in the width direction of the support body and extend substantially perpendicularly to the thickness direction of the electrode body. According to the power storage element having such a configuration, the space for disposing the current collecting terminal can be reduced. It is preferable that a space that opens toward the end surface of the electrode body is formed between both blade portions. In this case, connection (typically welding) between the collector terminal and the electrode sheet is easy.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) This embodiment is an example in which the present invention is applied to an electric double layer capacitor. As shown in FIGS.
An electric double layer capacitor (for example, a power capacitor used in a vehicle or the like) 1 is a storage element container 2 made of a conductive metal such as aluminum and having a rectangular parallelepiped shape, and a flat shape wound in the container 2. Electrode body 10
And two current collecting bars (current collecting terminals) 40 respectively connected to the positive electrode sheet 12 and the negative electrode sheet 14 which constitute both axial end portions (left and right end portions in FIG. 1) of the electrode body 10, and these current collecting bars. Two insulating members 5 arranged to engage the bar 40
0 and the container 2 connected to each collector bar 40
And two external terminals 60 protruding outside. The container 2 contains an electrolytic solution (not shown), and the electrode body 10 is impregnated with the electrolytic solution.

The storage element container 2 includes a box-shaped case 20 having an opening at the upper end, and a lid 30 attached to the opening and sealing the case 20. The cover 30 is formed with two terminal mounting holes 32 through which the two current collecting bars 40 respectively pass. As shown in FIGS. 1 and 2, between the current collecting bar 40 and the inner surface of the lid body 30 (the lower surface of FIG. 1), between the current collecting bar 40 and the inner periphery of the terminal mounting hole 32, and the current collecting. Between the bar 40 and the side wall of the case 20,
The direct contact is blocked by the insulating member 50. This maintains the insulation between the collector bar 40 and the container 2. The insulating member 50 is manufactured by injection molding of PPS (polyphenylene sulfide resin).

The collector bar 40 has a lead-out portion 41 extending from one end in the long side direction of the electrode body 10 to a substantially central portion (winding shaft portion) along the end face, and one end of the lead-out portion 41 (lower end in FIG. 1). )
A sheet connecting portion 42 formed subsequently to the above, and an external terminal connecting portion 44 formed following the other end (upper end in FIG. 1) of the lead-out portion 41. The entire shape of the current collecting bar 40 is formed by bending and pressing an aluminum plate having a thickness of 1.2 mm. The collector bar 40 may be formed by forging or the like.

The sheet connecting portion 42 provided at the lower end of the current collecting bar 40 has a bent plate-shaped supporting portion 43 which enters the inside (the winding inner peripheral portion) of the electrode body 10 from the end face thereof. The support part 43 is a first flat plate part 43 a extending in the axial direction of the electrode body 10.
And a second flat plate portion 43b extending in the long side direction, and has an L-shape as a whole. Two wing portions 45 are formed following both ends of the second flat plate portion 43b in the width direction.
These wing portions 45 are formed in the winding inner peripheral portion of the electrode body 10 substantially perpendicular to the thickness direction of the electrode body 10.
Extends toward the end face of the. As shown in FIG. 3, the wings 4
The cross-sectional shape (cross-section along the thickness direction of the electrode body 10) of the sheet connecting portion 42 in the portion where 5 is formed is a U-shape. These wing portions 45 are respectively biased to one side and the other side in the thickness direction of the electrode body 10. A space K that opens to the end surface of the electrode body 10 is formed between the two wings 45. The space K is partitioned by the first flat plate portion 43a (see FIG. 1), the second flat plate portion 43b, and the two blade portions 45.

The sheet connecting portion 42 of the collector bar 40
In addition to the shapes shown in FIGS. 1 to 3, the support portion 43 does not have the second flat plate portion 43b, and the first flat plate portion 43 has the shape shown in FIG.
The wings 45 may extend from both ends of a in the width direction. The wing portion 45 is provided in the winding inner peripheral portion of the electrode body 10 substantially perpendicular to the thickness direction of the electrode body 10.
Can be formed so as to extend downward in the long side direction.

As shown in FIGS. 3 and 5, the positive electrode sheet 12 and the negative electrode sheet 14 are divided into two on both sides in the thickness direction with the winding inner peripheral portion of the electrode body 10 as a boundary. Each of the divided portions is gathered (bundled) from both the outer peripheral side and the inner peripheral side of the electrode body 10 to their central portion (the central portion of the winding thickness of the electrode body 10). The gathered portions are welded (connected) on the surface (connection surface) 45a of the blade portion 45 which faces the electrode body 10 in the thickness direction. As shown in FIG. 5, the distance h1 between the two connection surfaces 45a is approximately half the thickness H of the electrode body 10. In addition, as shown in FIG. 1, all the connection surfaces 45 a are arranged at respective central portions in the long side direction of the electrode body 10.
Therefore, the connection points between the connection surface 45a and the positive electrode sheet 12 and the connection points between the connection surface 45a and the negative electrode sheet 14 are provided at positions that face each other at substantially equal intervals in the circumferential direction of the electrode body 10. There is.

The external terminal connecting portion 44 provided on the upper end of the collector bar 40 extends from the end portion of the electrode body 10 to the upper portion of the electrode body 10 along the inner surface of the lid body 30 as shown in FIG. There is. The external terminal connecting portion 44 has a current collecting cylindrical portion 46 that extends toward the opposite side of the electrode body 10 (the upper side in FIG. 1; the outer side of the container 2) and has a thread on the inner peripheral surface.
The current collecting cylindrical portion 46 can be formed, for example, by subjecting a metal plate (here, an aluminum plate) forming the current collecting bar 40 to a drawing process.

As shown in FIG. 1, an external terminal 60 is connected to the current collecting cylindrical portion 46. The external terminal 60 is made of a conductive metal such as aluminum. External terminal 6
The head portion 0 (portion protruding to the outside of the container 2) 62 has a cylindrical outer shape, and a tap 62a that opens to the upper end of the external terminal 60 is formed therein. Further, from the lower end of the head portion 62, a leg portion 64 having a thread on the outer peripheral surface extends. The external terminals 60 and the current collecting bar 40 are connected (connected) by screwing the leg portions 64 to the inner circumference of the current collecting cylindrical portion 46. In addition, the lower surface of the head 62 and the lid 3
An annular insulating packing 24 for insulating the both and airtightly sealing them is arranged between 0 and 0. The insulating packing 24 can be made of the same material as the insulating member 50, for example.

The structure of the electrode body 10, the manufacturing method thereof, and the connecting method of the electrode body 10 and the current collecting bar 40 will be described below. FIG. 6 shows a state before winding the positive electrode sheet 12 constituting the electrode body 10. The thickness of the positive electrode current collector 12 is 20 μ
A long aluminum foil of m was used. The paste containing the positive electrode active material was applied to both surfaces of the positive electrode current collector 12a to form the positive electrode active material layers 12b on both surfaces of the positive electrode current collector 12a. In this way, the positive electrode sheet 12 was produced. Here, on one long side of the positive electrode sheet 12, an active material uncoated portion 12c in which the positive electrode active material layer 12b is not formed on any surface is provided.

Since the structure of the negative electrode sheet 14 is the same as that of the positive electrode sheet 12, the negative electrode sheet 14 will be described with reference to FIG. The reference numerals in parentheses in FIG. 6 correspond to the negative electrode sheet 14. A negative electrode current collector 14a made of a long aluminum foil having a thickness of 20 μm was prepared, and a paste containing a negative electrode active material was applied to both surfaces thereof. In this way, the negative electrode sheet 14 having the negative electrode active material layers 14b formed on both surfaces was produced. On one long side of the negative electrode sheet 14, an active material uncoated portion 14c in which the negative electrode active material layer 14b is not formed on any surface is provided.

As a material for the positive electrode sheet and the negative electrode sheet, in addition to the aluminum used in this embodiment, a conductive metal such as nickel or copper can be used. Of these, it is particularly preferable to use aluminum or an aluminum alloy. Further, in this example, the positive electrode sheet and the negative electrode sheet made of the same material were used,
These may be formed of different materials.
Further, as the positive electrode or negative electrode active material used for manufacturing the electrode body 10, one or more active materials (typically carbon materials such as activated carbon) used in conventional electric double layer capacitors are used. It can be used without particular limitation.
In preparing a paste containing such an active material, conventionally known binders, solvents, conductive agents and the like can be appropriately used. For example, methyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride or the like can be used as a binder, water or N-methylpyrrolidone or the like can be used as a solvent, and carbon black or graphite can be used as a conductive material. The paste can be applied to the current collector by using a comma coater, a die coater or the like.

A porous polypropylene resin sheet was used as the separator. The planar shape of this separator is
In the positive electrode sheet 12 shown in FIG. 6, the positive electrode active material layer 12b
It has almost the same shape as the region in which is formed. Both the electrode sheets 12 and 14 and the two separators 16 are stacked in this order on the separator 16, the positive electrode sheet 12, the separator 16 and the negative electrode sheet 14, as shown in FIG. 7. At this time, the active material uncoated portion 12c of the positive electrode sheet 12 and the active material uncoated portion 14c of the negative electrode sheet 14 protrude from one long side and the other long side of the separator 16, respectively. To place.

The stacked electrode sheets 12 and 14 and the separator 16 are wound in the long side direction using a winding machine or the like. Typically, the electrode sheets 12 and 14 and the separator 16 are wound around a winding core provided in the winding machine.
After that, when the winding core is removed, as shown in FIG. 8, a tubular electrode body 10 ′ having a space L formed in the portion where the winding core was present (the winding inner peripheral portion) is obtained. The number of windings of the electrode body 10 included in the electricity storage device of this example was 16.

Here, collector bars 40 are arranged at both axial ends of the cylindrical electrode body 10 '. At this time, as shown in FIG. 8, the sheet connecting portion 42 may be inserted into the space L from both end surfaces of the tubular electrode body 10 ′ substantially along the winding axis of the tubular electrode body 10 ′. . In this state, the cylindrical electrode body 10 '
Are compressed in the radial direction (left and right direction in FIG. 8). As a result, the cylindrical electrode body 10 'is formed into a flat shape to form the electrode body 10. At this time, as shown in FIG. 9, the positive electrode sheet 12 (active material uncoated portion 12) forming the axial end portion of the electrode body 10 is formed.
The inner peripheral side of c) is pressed onto both connecting surfaces 45a located outside the seat connecting portion 42. As a result, the positive electrode sheets 10 are gathered from the inner peripheral side to the outer peripheral side of the electrode body 10. Further, as shown in FIG. 9, the axial end portion of the electrode body 10 is compressed more than the axial center portion of the electrode body 10 (the portion where the separator is disposed). As a result, the positive electrode sheet 1 moves from the outer peripheral side to the inner peripheral side of the electrode body 10.
2 are collected together. In this way, the positive electrode sheets 12 are gathered together on the connection surface 45a from both the outer peripheral side and the inner peripheral side of the electrode body 10. In addition, here, the positive electrode sheet 1
2 shows the side protruding (the positive electrode side end portion), the negative electrode sheet 14 is gathered on the connection surface 45a in the same manner on the side where the negative electrode sheet 14 protrudes (the negative electrode side end portion). In the electricity storage device of this example, the thickness H of the electrode body 10 formed into a flat shape (the thickness of the portion wound with the separator 16; see FIG. 5) is about 2 cm, and the electrode body 10 is
The thickness of the portion where the positive electrode sheets 12 were gathered together at the axial end portion (the thickness of the portion welded to the connection surface 45a) was about 320 μm per portion.

The positive electrode sheets 12 gathered on the connection surface 45a are ultrasonically welded to the connection surface 45a. At this time, as shown in FIG.
The anvil 72 is inserted into the space K between the a and the one wing portion 45
It is placed in contact with the inner side surface 45b (located on the upper side in FIG. 10). In addition, the connecting surface 45a of the one wing portion 45
The horn 74 is arranged so as to sandwich the positive electrode sheet 12 collected on the positive electrode sheet 12. In this state, the positive electrode sheet 12 is welded and fixed to the one wing portion 45 (connection surface 45a).

Next, when the electrode body 10 is rotated half a turn around its winding axis, one of the blades 45 is rotated before the half rotation.
The other wing portion 45 (connection surface 45a) is arranged at substantially the same position as the position where (connection surface 45a) was located. Therefore,
In the long side direction of the electrode body 10 (vertical direction in FIG. 2), the positions of the anvil 72 and the horn 74 are not moved, and the positive electrode sheets 12 bundled in two are bundled in one wing portion 45 and the other. Can be successively welded to the wings 45 of the. Although the case where the positive electrode side end portion of the electrode body 10 is welded (connected) to the current collecting bar 40 has been described here, the negative electrode side end portion of the electrode body 10 can also be welded by the same operation.

When the positive electrode sheet 12 is welded to the one connecting surface 45a of the current collecting bar 40 and the remaining positive electrode sheet 12 is welded to the other connecting surface 45a, as shown in FIG. On the surface 45a side, the contact plate 76 can be arranged from the outside of the welded portion to perform welding. This can improve the welding reliability (eg, welding strength) of the previously welded portion. This method is particularly effective when the distance h1 (see FIG. 5) between the two connecting surfaces is relatively close. In addition, as described above, the two connecting surfaces 4 of the collector bar 40
In addition to the method of sequentially welding the positive electrode sheet 12 to the 5a, by adjusting the thickness of the anvil 72 and using the two horns 74, the positive electrode sheet 12 is connected to the two connecting surfaces 45a.
May be welded at the same time. According to this method, productivity can be improved.

In the connection structure of this embodiment, as shown in FIG. 3, the electrode sheet 1 constituting the axial end portion of the electrode body 10 is formed.
The electrodes 2 and 14 are divided into two and gathered from the central portion (the winding inner peripheral portion) in the thickness direction of the electrode body 10. Also,
The gathered positions are the central portions of the outer circumference and the inner circumference of the electrode body 10. Thereby, as compared with the configuration (see FIG. 13) in which the entire electrode sheets 12 and 14 forming the axial end portion of the electrode body 10 are gathered together at one location in the thickness direction of the electrode body 10 (see FIG. 13). Of these, the width of the collector terminal connecting portion can be reduced. Therefore, the mounting efficiency of the storage element can be improved. Moreover, since the electrode sheets 12 and 14 thus divided and gathered together are welded to the connection surface 45a, respectively, the electrode sheets 12 and 1 to be welded at one place.
The thickness of No. 4 can be made small (about half that in the case of gathering together at one place in the thickness direction as shown in FIG. 13). This improves welding reliability. The effect is that the number of windings of the electrode body is relatively large (for example, the number of windings is 40 or more).
Especially well demonstrated if.

The electric double layer capacitor 1 can be manufactured, for example, in the following manner from the electrode body 10 to which the collector bar 40 is connected in this way. As shown in FIG. 11, the electrode body 10 to which the collector bar 40 is connected is attached to the case 2
It is accommodated sideways inside the 0 opening. As shown in FIG. 12, from the opening of the case 20, the collector bar 4
The insulating member 50 is arranged by engaging with the external terminal connecting portion 44 of No. 0. Next, the lid 30 is attached to the opening of the case 20. At this time, the current collecting cylindrical portion 46 and the portion of the insulating member 50 that covers the outer periphery thereof are inserted into the terminal mounting holes 32. Then, the opening portion of the case 20 and the peripheral portion of the lid body 30 are joined by laser welding or the like to form the energy storage device intermediate body 3 in which the case 20 is sealed (sealed) by the lid body 30.

As shown in FIG. 12, the electricity storage element structure 3 is formed with a communication passage P for communicating the inside and outside of the electricity collection cylindrical portion 46 inserted into the terminal mounting hole 32. An electrolytic solution is injected into the storage element structure 3 from the communication path P. Here, propylene carbonate (containing tetraethylammonium tetrafluoroborate 0.5 mol / liter) was used as the electrolytic solution. Then, as shown in FIG.
Insulating packing 24 is arranged around 2. Next, the leg portion 64 of the external terminal 60 is screwed to the current collecting cylindrical portion 46.
At this time, the insulating member 50 contacts the inner wall of the case 20 to prevent the external terminal connecting portion 44 from rotating (co-rotating) as the external terminal 60 rotates in the screwing direction. In this way, the external terminal 60 was connected to the collector bar 40, and the communication passage P (see FIG. 12) formed in the collector cylindrical portion 46 was closed.

An electrolytic solution inlet (through hole; not shown) is formed in the lid 30 or part of the case 20 separately from the terminal mounting hole 32, and the intermediate portion of the storage element is formed from the electrolytic solution inlet. The electrolytic solution may be injected into the body 3. In this case, the electrolytic solution inlet may be closed by a sealing member different from the external terminal 60 in any subsequent process. As described above, the electric double layer capacitor 1 is manufactured by sequentially assembling the electrode body 10, the insulating member 50, the lid body 30, the insulating packing 24, and the external terminal 60 to which the collector bar 40 is connected from above the case 20. can do.

(Second Embodiment) This embodiment is another example in which the present invention is applied to an electric double layer capacitor. Hereinafter, members having the same functions as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 14, in the collector bar 40 constituting the capacitor of this embodiment, the end face of the flat electrode body 10 (here, the end face at the negative electrode side end portion is shown) in order from the bottom. From the sheet connecting portion 42 to the inner circumferential portion of the winding, the flat sheet-shaped lead-out portion 14 extending in the long side direction from the sheet connecting portion 42 along the end face of the electrode body 10, and the upper end of the lead-out portion 14. The external terminal connection portion 44 is formed by bending at a substantially right angle. Since the collector bar 40 having such a shape has a relatively simple shape, it can be easily manufactured by, for example, bending (typically pressing) a single metal plate.

As shown in FIG. 15, the front surface (connecting surface) 42a and the back surface (connecting surface) 42b of the sheet connecting portion 42 face outward in the thickness direction of the electrode body 10. These negative electrode sheets 14 are gathered from the outer peripheral side to the inner peripheral side of the electrode body 10 on the connection surfaces 42a and 42b. In addition, the negative electrode sheet 14 is gathered (pushed out) from the inner peripheral side to the outer peripheral side by the thickness (plate thickness) of the sheet connecting portion 42.
There is. In this way, the negative electrode sheet 14 is gathered between them from both the outer peripheral side and the inner peripheral side, and the connecting surfaces 42a, 4
2b is connected (for example, by ultrasonic welding). A collector bar 40 is similarly connected to the positive electrode side end portion (not shown) of the electrode body 10.

As shown in FIG. 14, the external terminal connecting portion 44
A through hole 47 is provided in the. The lower end of the external terminal 60 is connected to the through hole 47 by penetrating the lid body 30.
At this time, by disposing the insulating packing 24 between the external terminal 60 and the lid 30, both are insulated and airtightly sealed. In this way, the electrode body 10, the current collecting bar 40, the external terminal 60, and the lid body 30 are integrated. A capacitor is obtained by housing this together with an electrolytic solution in a case 20 (see FIG. 1) and sealing it.

In the structure of this embodiment, the negative electrode sheet 14 constituting the axial end portion of the electrode body 10 is divided and gathered on both sides in the thickness direction with the winding inner peripheral portion as a boundary. Each of the divided parts is gathered together to form the connecting surfaces 42a, 4a.
Welded to 2b. Therefore, the welding reliability can be improved as compared with a configuration in which the negative electrode sheets 14 are gathered in one place from the entire thickness direction. Further, since the good connectivity can be obtained even if the number of windings is increased, the degree of freedom in designing the electrode body can be increased. Since the negative electrode sheet 14 is gathered from both the outer peripheral side and the inner peripheral side of the electrode body 10 between them, the width of the collector terminal connecting portion can be made smaller than that of the configuration in which the negative electrode sheets 14 are gathered in one place. Can be made smaller. Therefore, the mounting efficiency of the capacitor can be improved.
It is preferable that the thickness of the sheet connecting portion 41 (that is, the distance h1 between the connecting surface 42a and the connecting surface 42b; see FIG. 15) is approximately half the thickness of the electrode body 10. Further, it is preferable that the negative electrode sheet 14 is gathered at the central portion of the outer circumference and the inner circumference of the electrode body 10. In such a case, the effect of reducing the width of the collector terminal connecting portion is particularly great.

This embodiment is preferably applied to a capacitor having a relatively thin electrode body. Although not particularly limited, the thickness of the sheet connecting portion is, for example, about 0.5 to 5 mm.
The preferred thickness is in the range of about 1 to 3 mm, and the more preferred thickness is in the range of about 1.5 to 2.5 mm.

(Third Embodiment) This embodiment relates to a capacitor constructed by using a collector bar having a sheet connecting portion having a shape different from that of the second embodiment.

As shown in FIGS. 16 and 17, a bent plate-shaped sheet connecting portion 42 is inserted in the winding inner peripheral portion of the electrode body 10. The lower portion of the sheet connecting portion 42 constitutes a plate-shaped first unevenly distributed portion 421 which is biased to one side (the left side in FIG. 17) of the thickness of the electrode body 10 and is substantially perpendicular to the thickness direction thereof. Further, the upper part of the sheet connecting portion 42 has the electrode body 1
The second unevenly distributed portion 422 is formed in a flat plate shape that is biased to the other side (the right side in FIG. 17) of the thickness of 0 and is substantially perpendicular to the thickness direction. The shape of the other part of the current collecting bar 40 is almost the same as that of the second embodiment. Like the current collecting bar 40 used in the second embodiment, the current collecting bar 40 having such a shape can be easily manufactured by bending (typically pressing) a single metal plate. it can. Therefore, the cost can be reduced as compared with, for example, a case where the current collecting bar is manufactured by carving metal.

As shown in FIG. 17, the negative electrode sheets 14 are gathered together on the surface (connection surface) 42a of the first unevenly distributed portion 421, which is closer to the negative electrode sheet 14 (projecting side). In addition, the negative electrode sheet 14 is gathered together on the surface (connection surface) 42b of the second unevenly distributed portion 422, which is closer to the negative electrode sheet 14 (projecting side). Since the unevenly distributed portions 421 and 422 are arranged so as to be displaced from each other with respect to the long side direction (vertical direction in FIG. 17) in the cross section of the electrode body 10, the connection surface 42 is formed.
The positions of a and 42b are also displaced in the long side direction (up and down). In addition, since the sheet connecting portion 42 is bent, a space that is opened to the end surface of the electrode body 10 is formed between the sheet connecting portion 42 and the inner periphery of the negative electrode sheet 14 on the back side of the connecting surfaces 42a and 42b. K is formed.

According to this structure, two sets of anvils 72 are provided.
And the horn 74, these two connecting surfaces 42
The negative electrode sheets 14 gathered on the a and 42b can be welded at one time. For example, as shown in FIG. 17, two anvils 72 are respectively inserted from the end faces of the electrode bodies into the space K formed on the back side of the connection faces 42a and 42b.
Between the anvil 74 and the horn 74, the negative electrode sheet 14 gathered on the first unevenly distributed portion 421 and the connection surface 42a thereof, the second unevenly distributed portion 422 and the connection surface 4 thereof.
The negative electrode sheets 14 gathered on the 2b may be sandwiched and ultrasonically welded at one time. The collector bar 40 can be similarly connected to the positive electrode side end portion (not shown) of the electrode body 10.

In this embodiment, since the connecting surfaces 42a and 42b are displaced in the direction of the longer side in the cross section of the electrode body (up and down), the two sets of the anvil 72 and the horn 74 do not buffer each other during welding. Can be placed. As a result, the negative electrode sheets 14 gathered on the respective connecting surfaces can be welded to the two connecting surfaces 42a and 42b at once. Also, these connection surfaces 42a, 42b
Alternatively, the negative electrode sheets 14 may be welded separately (sequentially).
For example, the negative electrode sheet 14 may be connected to the connecting surface 42b after the negative electrode sheet 14 is connected to the connecting surface 42a. The distance h1 (see FIG. 17) between the connecting surface 42a and the connecting surface 42b is preferably about half the thickness of the electrode body 10.

(Fourth Embodiment) This embodiment relates to a capacitor formed by connecting an electrode sheet to a side end surface of a plate-shaped sheet connecting portion.

As shown in FIGS. 18 and 19, a flat sheet connecting portion 42 is formed at the lower end of the collector bar 40. The seat connecting portion 42 has both end surfaces (connecting surfaces).
Inserted from the positive electrode side end surface (the left end in FIG. 18) and the negative electrode side end surface (the right end in FIG. 18) of the electrode body 10 into the winding inner circumferential portion so that the electrodes 42a and 42b face outward in the thickness direction of the electrode body 10. ing. As shown in FIG. 18, the lead-out portion 41 provided continuously above the sheet connecting portion 42 extends in the long side direction along the end face of the electrode body 10.

As shown in FIG. 19, a recess 48a is formed in the upper part of the seat connecting portion 42 on the back side of the connecting surface 42a (on the connecting surface 42b side). In addition, the seat connecting portion 42
On the lower side of the connection surface 42b side (connection surface 42a side)
A recess 48b is formed in the. As described above, since the sheet connecting portion 42 is partially cut away to form the recesses 48a and 48b, the space K opening to the end surface of the electrode body 10 is formed on the back side of the connecting surfaces 42a and 42b. Has been formed. Since the collector bar 40 having such a shape has a relatively simple shape, it can be easily manufactured by bending (typically pressing) a single metal plate.

According to this structure, as in the third embodiment, the two sets of anvil 72 and horn 74 are used to collect the electrode sheets 12, 14 gathered on the two connecting surfaces 42a, 42b at once. Can be welded. The width of the sheet connecting portion 42 (that is, the distance h1 between the connecting surface 42a and the connecting surface 42b; see FIG. 19) is determined by the electrode body 10
Is preferably about half the thickness of

(Fifth Embodiment) This embodiment relates to a capacitor formed by using a collector bar having a shape different from that of the fourth embodiment.

As shown in FIGS. 20 and 21, the current collector bar 40 is formed with a sheet connecting portion 42 and a lead-out portion continuing to the upper end thereof. The overall shape of the current collecting bar 40 is a linear shape extending along a plane substantially perpendicular to the winding axis of the electrode body 10. Inside the electrode body 10, a sheet connecting portion 42 having a shape similar to that of the fourth embodiment is inserted.
Further, as shown in FIG. 20, the positive electrode sheet 12 and the negative electrode sheet 14 forming the both ends of the electrode body 10 are
The part that constitutes the upper part of is cut. This avoids buffering with the lead-out part 41 which extends straightly upward following the seat connecting part 42.

Since the current collecting bar 40 of this embodiment has a linear shape and a simple shape, it can be easily manufactured from a single metal plate by punching, pressing or the like. it can. Further, since the collector bar 40 can be housed inside the axial length of the electrode body 10, the container 2
The space efficiency inside (see FIG. 1) can be improved.

Although the electric double layer capacitor and the method of manufacturing the same have been described in the above embodiments, the present invention is applicable to other types of batteries such as a lithium ion secondary battery, a nickel hydrogen battery, a nickel cadmium battery (primary battery or secondary battery). Batteries), capacitors other than electric double layer capacitors, and other storage elements. The materials of the positive and negative electrode active materials, the current collector sheet, the separator, the current collector bar, the external terminals and the storage element container, the composition of the electrolytic solution, and the like are appropriately selected depending on the type of the storage element. It should be noted that the idea of the present invention is not limited to a power storage element having a spirally wound electrode body, and can be applied to a power storage element having a laminated type electrode body or the like.

Further, as a technical matter to be understood from the description of the present specification, a sheet connecting portion having two connecting surfaces from the axial end portion of the flatly wound electrode body is provided on the winding inner peripheral portion. An example of the storage element is an electrode sheet that is inserted and has electrode sheets gathered from two sides in the circumferential direction of the electrode body and gathered from the outer peripheral side or the inner peripheral side to each of the two connection surfaces.
That is, the method of gathering the electrode sheets in the portion connected to the connection surface may be from at least one of the outer peripheral side and the inner peripheral side, and is not limited to both the outer peripheral side and the inner peripheral side. Also,
The gathered portions may be between the outer circumference and the inner circumference of the electrode body, and may not be between the outer circumference and the inner circumference. According to the power storage device having such a configuration, the electrode sheets that form the axial end portions of the electrode body are bisected in the thickness direction from the winding inner peripheral portion of the electrode body and gathered together, so that the electrode sheet is provided at one location. The welding reliability with the seat connection portion can be improved as compared with a configuration in which the sheets are gathered together. Further, even if the number of windings is increased, good connectivity can be obtained, so that the degree of freedom in design can be increased.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. Further, the technical elements described in the present specification or the drawings are
The technical usefulness is exhibited alone or in various combinations, and is not limited to the combinations described in the claims at the time of filing. In addition, the technique illustrated in the present specification or the drawings achieves a plurality of purposes at the same time, and achieving the one purpose among them has technical utility.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an electric double layer capacitor according to a first embodiment.

FIG. 2 is a sectional view taken along line II-II of FIG.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a cross-sectional view showing an example of a current collecting bar in which the shape of the seat connecting portion is different.

5 is a partially enlarged view of FIG.

FIG. 6 is a plan view showing a positive electrode sheet forming an electrode body.

FIG. 7 is a plan view showing an electrode body before winding.

FIG. 8 is a side view showing an electrode body wound in a tubular shape.

FIG. 9 is a side view showing a step of collecting electrode sheets on a connection surface.

FIG. 10 is a cross-sectional view showing a step of welding an electrode sheet to a connection surface.

FIG. 11 is a cross-sectional view showing a state in which an electrode body connected to a collector bar is housed in a case in the manufacturing process of the electric double layer capacitor according to the first example.

FIG. 12 is a cross-sectional view showing a state in which a case is sealed to form a storage element intermediate in the manufacturing process of the electric double layer capacitor according to the first example.

FIG. 13 is a cross-sectional view schematically showing an example of a conventional power storage element current collecting structure.

FIG. 14 is an exploded perspective view showing a connection structure of a collector bar, an electrode body, and an external terminal in the electric double layer capacitor according to the second embodiment.

FIG. 15 shows the electrode body connected to the collector bar as XV in FIG.
It is a sectional view taken along the line XV.

FIG. 16 is an exploded perspective view showing a connection structure of a collector bar, an electrode body, and an external terminal in the electric double layer capacitor according to the third embodiment.

FIG. 17 shows the electrode body connected to the collector bar as XV in FIG.
FIG. 7 is a sectional view taken along line II-XVII.

FIG. 18 is a side view showing an electrode body and a current collecting bar of an electric double layer capacitor according to a fourth embodiment.

FIG. 19 is a view on arrow XIX in FIG. 18.

FIG. 20 is a side view showing an electrode body and a current collecting bar of the electric double layer capacitor according to the fifth embodiment.

21 is a view taken in the direction of arrow XXI-XXI in FIG. 20.

[Explanation of symbols] 1: Electric double layer capacitor (electric storage element) 10: Electrode body 12: Positive electrode sheet 14: Negative electrode sheet 16: Separator 2: Storage element container 40: collector bar (collector terminal) 42: Seat connection part 42a, 42b: connection surface 44: External terminal connection part 45: Wing 45a: connection surface 48a, 48b: concave portions 60: External terminal 72: Anvil 74: Horn K: Space open to the end face of the electrode body H: Thickness of electrode body h1: Distance between connecting surfaces

Continued front page    (72) Inventor Tomohiro Matsuura             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. (72) Inventor Hiroshi Inukai             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F term (reference) 5H022 AA04 AA09 AA18 BB01 BB03                       BB11 BB17 CC13 CC19 CC22                       EE01

Claims (12)

[Claims] 1. An electrode body, in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween, and a collector terminal connected to an axial end portion of the electrode body. A sheet connecting portion having a plurality of connecting surfaces is formed, and the sheet connecting portion is inserted from the axial end portion of the electrode body to the winding inner peripheral portion of the electrode body to form the axial end portion. The positive or negative electrode sheet is gathered between the outer peripheral side and the inner peripheral side at a plurality of locations in the circumferential direction of the electrode body, and each of the gathered locations is a plurality of connecting surfaces. An electric storage element, which is connected to each of the. 2. The electrode body is wound in a flat shape,
The electricity storage device according to claim 1, wherein the sheet connecting portion has two connecting surfaces, and the two connecting surfaces face outward in a thickness direction of the flat electrode body. 3. The electricity storage device according to claim 2, wherein the sheet connecting portion has a flat plate shape, and the two connecting surfaces are formed on a front surface and a back surface of the flat plate. 4. The sheet connecting portion has a bent plate shape, and by the bending, a portion biased to one side in the thickness direction of the electrode body and a portion biased to the other side are formed. The power storage element according to claim 2, wherein the two connection surfaces are formed on the surfaces of the protruding portions of the portion biased to one side and the portion biased to the other side, respectively. 5. The electricity storage device according to claim 2, wherein the sheet connecting portion is plate-shaped, and the two connecting surfaces are formed at both end surfaces in the width direction of the plate. 6. The electricity storage device according to claim 2, wherein the distance between the two connection surfaces is approximately half the thickness of the electrode body. 7. The space according to claim 1, wherein a space opened to an end face of the electrode body is formed on the back surface side of the portion where the gathered electrode sheets are connected to the connection surface. The electricity storage device described. 8. The electricity storage device according to claim 1, wherein a space that opens to an end surface of the electrode body is formed between the plurality of connection surfaces. 9. A method of manufacturing a power storage device having a flat electrode body, comprising a step of preparing a current collecting terminal having a sheet connecting portion having two connecting surfaces, and a positive electrode sheet and a negative electrode sheet. A step of producing a tubular electrode body wound via a separator, a step of inserting a sheet connecting portion from an axial end of the tubular electrode body to a winding inner peripheral portion, and the tubular electrode body Squeezing into a flat shape, and a step of gathering either positive or negative electrode sheets that form the axial end portion of the electrode body on the two connecting surfaces of the sheet connecting portion, and the gathering And a step of connecting an electrode sheet to a connection surface. 10. The method according to claim 9, wherein the step of connecting the electrode sheet to the connection surface is performed by ultrasonic welding. 11. In the ultrasonic welding method, an anvil is inserted on the back side of the connection surface, and the connection surface and an electrode sheet gathered on the connection surface are sandwiched between the anvil and the horn. The method of manufacturing a storage element according to claim 10, which is performed. 12. In the ultrasonic welding method, an anvil is inserted between the two connecting surfaces, and any connecting surface between the anvil and the horn and an electrode sheet gathered on the connecting surface. 11. The method for manufacturing an electricity storage device according to claim 10, wherein the method is performed with sandwiching between and.