JP4061938B2 - Storage element and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power storage device and a method for manufacturing the same.
In this specification, the “storage element” is a concept including both a battery (such as a lithium ion battery and a nickel metal hydride battery) and a capacitor (such as an electric double layer capacitor).
[0002]
[Prior art]
2. Description of the Related Art An electric storage element including an electrode body in which a positive electrode sheet and a negative electrode sheet are wound via a separator is known. In many of such power storage elements, the positive electrode sheet and the negative electrode sheet that protrude from both sides of the separator constitute one end and the other end in the axial direction of the electrode body. In a power storage device having such an electrode body, the main method for connecting the electrode body and the terminal is as follows: (1). An electrode sheet in which a large number of current collecting tabs are welded to the side end (the part protruding from the separator). (2). The axial end of the electrode body is moved from the outer periphery side to the inner periphery side (from the radially outer side). There is a method of gathering electrode sheets by compressing them (to the center side) and connecting terminals to the gathered parts. In general, the method (2). Has higher productivity than the method (1). The method (2). Is also advantageous in terms of downsizing the electric storage element.
[0003]
FIG. 13 is a cross-sectional view schematically showing an example of a structure in which a current collecting terminal 140 is connected to the positive electrode side of a flatly wound electrode body (flat electrode body) 10 by applying the method (2). FIG. In FIG. 13, reference numeral 12 denotes a positive electrode sheet, reference numeral 14 denotes a negative electrode sheet, and reference numeral 16 denotes a separator. Note that an active material layer (not shown) is formed on each of the positive electrode sheet 12 and the negative electrode sheet 14 which are laminated with the separator 16. The positive electrode sheet 12 constituting the axial end portion of the electrode body 10 is gathered from one side in the thickness direction of the electrode body 10 (left and right direction in FIG. 13) to one place in the substantially central portion. A current collecting terminal 140 is connected to the positive electrode sheet 12 gathered in this way 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. FIG.
[0004]
[Problems to be solved by the invention]
However, in such a current collecting structure, if the current collecting terminal 140 is also connected to the positive electrode sheet 12 located on the outer peripheral side (left and right ends in FIG. 13) of the electrode body 10, the current collector terminal 140 protrudes from the separator 16 in the positive electrode sheet 12. The width of the portion (the portion for connecting the positive electrode sheet 12 to the current collecting terminal 140 and not having the active material layer; hereinafter, also referred to as “current collecting terminal connecting portion”) is increased. Since the portion where the active material layer is not formed (current collector terminal connection portion) does not contribute to the electrode reaction, the width can be reduced from the viewpoint of improving the capacity per unit capacity (mounting efficiency). preferable.
[0005]
Japanese Patent Laid-Open No. 2000-223109 uses a current collector (current collector terminal) in which a metal plate is repeatedly bent into a corrugated plate shape, and sandwiches a large number of electrode sheets into each corrugated plate gap. A technique for pressing and welding from both sides is disclosed. However, with this technique, the operation of sandwiching the electrode sheet into each corrugated gap is complicated, and it is difficult to reliably weld the current collector to the electrode sheet. As described above, the technology described in the above publication has room for further improvement in terms of productivity (particularly, workability when arranging the current collecting terminals and connecting the current collecting terminals and the electrode sheet). .
[0006]
The objective of this invention is providing the electrical storage element which can reduce the width | variety of the part which protrudes from a separator among electrode sheets, and is wound, and its manufacturing method.
[0007]
[Means, actions and effects for solving problems]
The present inventor has found that the above problem can be solved by collecting the electrode sheet protruding from the separator from both the outer peripheral side and the inner peripheral side of the wound electrode body.
[0008]
  The electricity storage device provided by the present invention includes a flat electrode body in which a positive electrode sheet and a negative electrode sheet are wound in a flat shape with a separator interposed therebetween, and a current collecting terminal connected to an axial end of the electrode body With. Multiple current collector terminalstwoA plate-like sheet connection portion having a flat connection surface is formed. The sheet connecting portion is from the axial end of the electrode body to the winding inner periphery of the electrode body.onlyHas been inserted.The two connection surfaces of the sheet connecting portion are directed to the outer side in the thickness direction of the electrode body at positions deviated to one side in the thickness direction of the electrode body and positions deviated to the other side.One of the positive and negative electrode sheets constituting the axial end of the electrode body is in the circumferential direction of the electrode body.twoIn placeOver the entire layer from the outer circumference to the inner circumferenceThey are gathered from both the outer peripheral side and the inner peripheral side between them (between the outer periphery and the inner periphery of the electrode body). Each of the gathered points (electrode sheets)twoFor each of the connection surfacesweldingHas been. The electrode sheet gathered from the inner peripheral side toward the outer peripheral side is the aforementionedConnection surfaceInweldingA space that opens to the end face of the electrode body is formed on the back side of the portion that is formed. In addition, the outer periphery and inner periphery of an electrode body here mean the outer periphery and inner periphery in the part wound with the separator among electrode bodies.
  In the electricity storage device having such a configuration, compared to a configuration in which the electrode sheet is gathered 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 wound out of the separator (collection) The width of the electric terminal connecting portion) can be reduced. Therefore, the mounting efficiency of the storage element can be improved. Moreover, the electrical storage element having a space opened on the end face of the electrode body has good connectivity (workability and / or connection reliability) when connecting the electrode sheets gathered to each connection face. . For example, ultrasonic welding can be performed by inserting an anvil from the end face of the electrode body into this space (the back side of the portion to which the electrode sheet is connected).
[0009]
  In the present invention, the sheet connecting portion provided in the power storage element has two connection surfaces.TheEach of these two connecting surfaces faces the outside in the thickness direction of the flat electrode body (refers to the short side direction in the cross section of the electrode body).The
  In the electricity storage device having such a configuration, the axial end portion of the electrode body is arranged from the inner peripheral side to the outer periphery by the connection surface of the sheet connecting portion inserted into the wound inner peripheral portion (central portion in the thickness direction) of the flat electrode body. It is spread to the side. As a result, the electrode sheet is 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 gathered from the outer peripheral side of the electrode body to the inner peripheral side on the connection surface of the sheet connecting portion. Thus, it is possible to easily realize the current collecting structure (connecting 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. it can.
[0010]
  As a preferred current collecting terminal provided in such a power storage element, a sheet connecting portion is provided.In a U shapeWhat is formed with the board | plate material bent is illustrated. Such a current collecting terminal can be easily manufactured from, for example, a single metal plate because the shape of the sheet connecting portion is simple.
[0011]
  As other preferable current collecting terminals, the sheet connecting portion is bent in a plate shape, and the bent portion is biased to one side in the thickness direction of the electrode body and the other portion is biased to the other side.Are displaced from each other along the long side direction at the axial end of the electrode body.What is formed is exemplified. It is preferable that the electrode sheet is gathered and connected to the surfaces (two connecting surfaces) on the protruding side of the portion biased to one side and the portion biased to the other side. Such a current collecting terminal can be easily manufactured by, for example, bending a single metal plate.
[0012]
  Still another preferred current collecting terminal is a sheet connection partBut widthOne whose both end faces in the direction face the thickness direction of the electrode body. The electrode sheets are preferably gathered and connected to their side end surfaces (two connecting surfaces). Such a current collecting terminal can be easily manufactured from, for example, a single metal plate because the shape of the sheet connecting portion is simple.
[0013]
When the electricity storage device of the present invention includes a flat electrode body, the preferable distance between the two connection surfaces of the sheet connection portion of the current collector terminal connected to the flat electrode body is approximately the thickness of the flat electrode body. It is half. The “interval between two connection surfaces” refers to 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 sheet is 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 connection surfaces 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 connection surfaces so that the distance h2 between the central positions of the thicknesses of the electrode sheets gathered on these connection 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 periphery and the inner periphery of the electrode body can be easily realized. In particular, when the center position between both connection surfaces and the center position in the thickness direction of the electrode body substantially coincide (for example, the deviation between the two is in the range of 0.4H to 0.6H), the current collector This is preferable because the effect of reducing the width of the terminal connection portion is great.
[0014]
The portion of the electrode sheet that constitutes the axial end of the electrode body that is not connected to the connection surface may or may not be gathered. There is no particular limitation on how to gather when they are gathered. For example, it 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 position may be between the outer periphery and inner periphery of the electrode body, or may be further inside (winding inner periphery) than the inner periphery of the electrode body. It is preferable that they are gathered inside the outer periphery of the electrode body.
[0015]
In a preferable one of the electricity storage devices of the present invention, a space that opens to the end surface of the electrode body (end surface with respect to the winding axis direction) is formed on the back side of the portion where the gathered electrode sheets are connected to the connection surface. ing.
The electricity storage device having such a configuration has good connectivity (workability and / or connection reliability) when connecting the electrode sheets collected on each connection surface. For example, ultrasonic welding can be performed by inserting an anvil from the end face of the electrode body into this space (the back side of the portion to which the electrode sheet is connected).
[0016]
In another preferable one of the electricity storage elements of the present invention, a space that opens to the end surface of the electrode body (the end surface with respect to the winding axis direction) is formed between the plurality of connection surfaces of the sheet connection portion.
The current collector terminal provided with the sheet connecting portion having such a shape has an electrode sheet as compared with a current collector terminal having a shape in which there is no space between connection surfaces (for example, a current collector terminal having a solid shape between the connection surfaces). Good connectivity. For example, ultrasonic welding can be performed by inserting an anvil into the space (between connecting surfaces) from the end face of the electrode body.
[0017]
One of the power storage elements of the present invention includes a power storage element container containing an electrode body, a current collecting terminal and an electrolyte, one end electrically connected to the current collecting terminal and the other end outside the power storage element container. An external terminal exposed (preferably protruding) can be further provided. Here, the current collecting terminal and the external terminal are preferably connected directly or via another rigid metal member (that is, without via a lead made of a metal foil, a metal wire or the like). In this case, the conduction 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 electricity storage element can be suppressed low. Further, the dimensions between the electrode body and the external terminal are easily determined, and the assembly is easy.
[0018]
  Moreover, according to this invention, the method of manufacturing an electrical storage element provided with a flat electrode body is provided. This methodA plate-like shape with a space between one flat connecting surface and the other flat connecting surfaceA step of preparing a current collector terminal on which a sheet connecting portion is formed, a step of producing a cylindrical electrode body in which a positive electrode sheet and a negative electrode sheet are wound via a separator, and an axial end of the cylindrical electrode body Inserting the sheet connection part from the part into the winding inner periphery, and crushing the cylindrical electrode body to form a flat shapeFrom both the outer peripheral side and the inner peripheral side at a plurality of locations in the circumferential direction of the electrode bodyIt includes a step of gathering either positive or negative electrode sheets constituting the axial end of the electrode body on two connection surfaces of the sheet connecting portion, and a step of connecting the gathered electrode sheets to the connection surface Do.
According to this manufacturing method, after inserting the sheet connecting portion into the winding inner peripheral portion (hollow portion) of the cylindrical electrode body, the electrode body is crushed into a flat shape, so that the operation of inserting the sheet connecting portion is easy. is there.
[0019]
The step of connecting the electrode sheet to the connection surface can be performed by various welding methods such as ultrasonic welding, resistance welding, and laser welding. Among these, it is particularly preferable to use an ultrasonic welding method.
[0020]
As a preferable mode for performing this 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 sandwiched between the anvil and the horn. Embodiments are illustrated. In such an embodiment, for example, a current collecting terminal is arranged so that a space opened on the end face of the electrode body is formed on the back side of each connection surface, and an anvil is inserted into this space from the axial end of the electrode body. Can be implemented. As another preferred embodiment, an anvil is inserted between two connection surfaces, and welding is performed by sandwiching one of the connection surfaces between the anvil and the horn and the electrode sheet gathered on the connection surface. Embodiments are illustrated. In such an embodiment, for example, a current collecting terminal is arranged so that a space opening in the end face of the electrode body is formed between the two connection surfaces, and an anvil is inserted into this space from the axial end of the electrode body. Can be implemented.
[0021]
The power storage device of the present invention or the production method of the present invention can be applied to various power storage devices including a wound electrode. For example, the present invention can be applied to both batteries and capacitors, and the type of electrolytic solution may be either aqueous or non-aqueous, and the composition thereof is not limited. Examples of the power storage element to which the present invention is preferably applied include an electric double layer capacitor and a lithium ion battery.
[0022]
In addition, as a power storage element in which the application of the present invention is particularly effective, various power storage elements (preferably an electric double layer capacitor or a lithium ion) provided with an electrode body having a relatively large distance (winding thickness) between the inner periphery and the outer periphery. 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 electrode body, the thickness H (see FIG. 5) in the cross section thereof is 2 cm. It is preferably applied to a power storage device including the electrode body as described above (typically 2 to 10 cm). Moreover, a big effect is acquired by applying to the various electrical storage element provided with the electrode body with many winding times of an electrode sheet. For example, it is preferably applied to a power storage element including an electrode body having a winding number of 15 or more (typically 15 to 120), more preferably 20 or more (typically 20 to 100).
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is also characterized by being implemented in the following forms.
[0024]
(Form 1)
An electrode sheet that forms the axial end of the electrode body is gathered together at the central portion of the outer periphery and inner periphery of the electrode body (that is, the central portion of the wound thickness of the electrode body).
Here, as shown in FIG. 5, the “central portion” means that the wound thickness of the electrode body 10 is T, and the collected electrode sheet (here, the positive electrode sheet 12 is shown) in the wound thickness direction. The distance t from the center position of the thickness of the electrode body 10 to the outer periphery of the electrode body 10 is approximately 0.5T (for example, in the range of 0.4T to 0.6T).
According to such a configuration, the effect of reducing the width of the current collecting terminal connection part (an effect of improving the mounting efficiency of the storage element) is great.
[0025]
(Form 2)
The connection surface of the current collector terminal and the connection portion of the electrode sheet are provided at substantially equal intervals in the circumferential direction of the electrode body.
According to such a configuration, current can be collected relatively uniformly from the entire electrode body. Thereby, the internal resistance of the electricity storage element can be lowered. In addition, the preferable number of this connection location is 2 in the case of a flat electrode body, and is 2-6 in the case of a cylindrical electrode body.
Moreover, it is preferable that the number of connection locations is an even number, and the connection locations are provided at locations facing each other. In this case, the operation of gathering the electrode sheets on the connection surface and / or the operation of connecting the gathered electrode sheets to the connection surface is easy.
[0026]
(Form 3)
In the electric storage element in which the electrode body is wound in a flat shape, the sheet connection portion has two connection surfaces, and the two connection surfaces face the outside in the thickness direction of the flat electrode body, the connection surfaces thereof Are arranged at each central portion 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 the electrode sheet is connected to one connection surface (for example, welding, preferably ultrasonic welding) and then the electrode body is rotated halfway around its winding axis, The other connection surface is arranged at substantially the same position as the connection surface. Therefore, workability at the time of sequentially connecting the electrode sheets to one connection surface and the other connection surface is good.
[0027]
(Form 4)
In the electric storage element in which the electrode body is wound in a flat shape, the sheet connection portion has two connection surfaces, and the two connection surfaces face the outside in the thickness direction of the flat electrode body, the connection surfaces thereof Are arranged so that their positions are shifted from each other (that is, the connection surfaces are not opposed to 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 an electrode sheet is simultaneously connected (ultrasonic welding) to one connection surface and the other connection surface.
[0028]
(Form 5)
The electrode body is wound in a flat shape, and the current collector terminal is formed following a lead portion extending along the end face of the electrode body in the long side direction in the cross section of the flat electrode body and one end of the lead portion. And a sheet connecting portion. The sheet connecting portion includes a support portion that enters the inside from the end face of the electrode body, and two wing portions that extend substantially perpendicular to the thickness direction of the electrode body from both ends in the width direction of the support portion inside the electrode body.
According to the electricity storage device having such a configuration, the arrangement space of the current collecting terminals can be reduced. It is preferable that a space that opens toward the end face of the electrode body is formed between the two wing portions. In this case, the current collector terminal and the electrode sheet can be easily connected (typically welding).
[0029]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
(First Example)
The present embodiment is an example in which the present invention is applied to an electric double layer capacitor.
As shown in FIGS. 1 to 3, an electric double layer capacitor (for example, a power capacitor used in a vehicle or the like) 1 includes a storage element container 2 made of a conductive metal such as aluminum and having a rectangular parallelepiped shape, and the container 2. Two electrode bodies 10 wound in a flat shape and connected to the positive electrode sheet 12 and the negative electrode sheet 14 constituting both axial ends of the electrode body 10 (left and right end portions in FIG. 1). A current collecting bar (current collecting terminal) 40, two insulating members 50 arranged to be engaged with these current collecting bars 40, and connected to each current collecting bar 40 and projecting outside the container 2. Two external terminals 60 are provided. The container 2 contains an electrolytic solution (not shown) and is impregnated in the electrode body 10.
[0030]
The storage element container 2 includes a box-shaped case 20 having an opening at the upper end, and a lid 30 that is attached to the opening and seals the case 20. The lid body 30 is formed with two terminal attachment holes 32 through which the two current collecting bars 40 respectively penetrate. As shown in FIGS. 1 and 2, between the current collector bar 40 and the inner surface of the lid 30 (lower surface in FIG. 1), between the current collector bar 40 and the inner periphery of the terminal mounting hole 32, and the current collector. The direct contact between the bar 40 and the side wall of the case 20 is blocked by the insulating member 50. As a result, the insulation between the current collecting bar 40 and the container 2 is maintained. The insulating member 50 is made by injection molding of PPS (polyphenylene sulfide resin).
[0031]
The current collector bar 40 continues from the one end in the long side direction along the end surface of the electrode body 10 to a substantially central portion (winding shaft portion), and one end of the lead portion 41 (lower end in FIG. 1). The sheet connection part 42 formed in this way and the external terminal connection part 44 formed subsequent to the other end (upper end in FIG. 1) of the drawer part 41 are configured. The overall shape of the current collecting bar 40 is formed by bending and pressing an aluminum plate having a thickness of 1.2 mm. The current collecting bar 40 may be formed by forging or the like.
[0032]
The sheet connecting portion 42 provided at the lower end of the current collecting bar 40 has a bent plate-like support portion 43 that enters the inside (winding inner peripheral portion) from the end face of the electrode body 10. The support portion 43 includes a first flat plate portion 43a 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 extend toward the end face of the electrode body 10 in the winding inner peripheral portion of the electrode body 10 substantially perpendicularly to the thickness direction of the electrode body 10. As shown in FIG. 3, the cross section of the sheet connecting portion 42 (the cross section along the thickness direction of the electrode body 10) in the portion where the wing portion 45 is formed is a U-shape. These wing portions 45 are biased to one side and the other side in the thickness direction of the electrode body 10, respectively. A space K that opens to the end face of the electrode body 10 is formed between the two wing portions 45. The space K is partitioned by a first flat plate portion 43a (see FIG. 1), a second flat plate portion 43b, and two wing portions 45.
[0033]
In addition to the shape shown in FIGS. 1 to 3, the sheet connecting portion 42 of the current collector bar 40 has a second flat plate portion 43 b as shown in FIG. 4, and the first flat plate portion 43 a. The shape which the wing | blade part 45 extended from the both ends of the width direction of this may be sufficient. The wing portion 45 can be formed so as to extend downward in the long side direction of the electrode body 10 substantially perpendicularly to the thickness direction of the electrode body 10 in the winding inner peripheral portion of the electrode body 10.
[0034]
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 the central portion thereof (central portion of the winding thickness of the electrode body 10). The gathered portion is welded (connected) onto a surface (connection surface) 45 a of the wing portion 45 facing the thickness direction outside of the electrode body 10. As shown in FIG. 5, the distance h 1 between the two connection surfaces 45 a is approximately half the thickness H of the electrode body 10.
As shown in FIG. 1, each connection surface 45 a is disposed at each central portion in the long side direction of the electrode body 10. Therefore, the connection portion between the connection surface 45a and the positive electrode sheet 12 and the connection portion between the connection surface 45a and the negative electrode sheet 14 are provided at positions facing each other at substantially equal intervals in the circumferential direction of the electrode body 10, respectively. Yes.
[0035]
As shown in FIG. 1, the external terminal connection portion 44 provided at the upper end of the current 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. The external terminal connecting portion 44 has a current collecting cylindrical portion 46 that extends toward the opposite side of the electrode body 10 (upper side in FIG. 1; outside the container 2) and has a thread on the inner peripheral surface. The current collecting cylindrical portion 46 can be formed, for example, by drawing a metal plate (here, an aluminum plate) constituting the current collecting bar 40.
[0036]
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. A head 62 (portion protruding outside the container 2) 62 of the external terminal 60 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 62, a leg portion 64 having a thread on the outer peripheral surface extends. The leg portion 64 is screwed to the inner periphery of the current collecting cylindrical portion 46, whereby the external terminal 60 and the current collecting bar 40 are connected (connected). An annular insulating packing 24 is disposed between the lower surface of the head 62 and the lid 30 to insulate and seal the two. The insulating packing 24 can be made of the same material as the insulating member 50, for example.
[0037]
Hereinafter, the configuration and manufacturing method of the electrode body 10 and the connection method between the electrode body 10 and the current collector bar 40 will be described.
A state before winding of the positive electrode sheet 12 constituting the electrode body 10 is shown in FIG. As the positive electrode current collector 12, a long aluminum foil having a thickness of 20 μm was used. A paste containing a positive electrode active material was applied to both surfaces of the positive electrode current collector 12a to form a positive electrode active material layer 12b on both surfaces of the positive electrode current collector 12a. In this way, a 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.
[0038]
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 also be described with reference to FIG. In FIG. 6, reference signs in parentheses 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. This produced the negative electrode sheet 14 in which the negative electrode active material layer 14b was formed in both surfaces. One long side of the negative electrode sheet 14 is provided with an active material uncoated portion 14c in which the negative electrode active material layer 14b is not formed on any surface.
[0039]
In addition, as a material which comprises a positive electrode sheet and a negative electrode sheet, electroconductive metals, such as nickel and copper other than the aluminum used in the present Example, can be used. Of these, it is particularly preferable to use aluminum or an aluminum alloy. Moreover, although the positive electrode sheet and negative electrode sheet which consist of the same material were used in the present Example, these may be formed from a mutually different material. Moreover, as an active material for positive electrodes or negative electrodes 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 the binder, water or N-methylpyrrolidone or the like can be used as the solvent, and carbon black or graphite can be used as the conductive material. Application of these pastes to the current collector can be performed using a comma coater, a die coater or the like.
[0040]
A porous polypropylene resin sheet was used as the separator. The planar shape of this separator is substantially the same shape as the region where the positive electrode active material layer 12b is formed in the positive electrode sheet 12 shown in FIG.
Both electrode sheets 12 and 14 and the two separators 16 are stacked in the order of the separator 16, the positive electrode sheet 12, the separator 16, and the negative electrode sheet 14, as shown in FIG. At this time, the electrode sheets 12, 14 so that 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. Place.
[0041]
The superimposed electrode sheets 12 and 14 and 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 the core provided in the winding machine. Thereafter, when the winding core is removed, as shown in FIG. 8, a cylindrical electrode body 10 ′ in which a space L is formed in a portion where the winding core is present (winding inner peripheral portion) is obtained. The number of windings of the electrode body 10 provided in the power storage device of this example is 16.
[0042]
Here, current collecting bars 40 are disposed 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 faces of the cylindrical electrode body 10 ′ substantially along the winding axis of the cylindrical electrode body 10 ′. . In this state, the cylindrical electrode body 10 'is compressed in the radial direction (left-right direction in FIG. 8). As a result, the cylindrical electrode body 10 ′ is formed into a flat shape to form an electrode body 10. At this time, as shown in FIG. 9, both connection surfaces in which the inner peripheral side of the positive electrode sheet 12 (active material uncoated portion 12 c) constituting the axial end portion of the electrode body 10 is located outside the sheet connection portion 42. Pressed onto 45a. Thereby, the positive electrode sheet 10 is collected from the inner peripheral side of the electrode body 10 to the outer peripheral side. Moreover, as shown in FIG. 9, the axial direction edge part of the electrode body 10 is compressed more compared with the axial center part (part in which the separator is disposed) of the electrode body 10. Thereby, the positive electrode sheet 12 is collected from the outer peripheral side of the electrode body 10 to the inner peripheral side. In this way, the positive electrode sheet 12 is gathered together on the connection surface 45a from both the outer peripheral side and the inner peripheral side of the electrode body 10. Here, the side where the positive electrode sheet 12 protrudes (the positive electrode side end) is shown, but the side where the negative electrode sheet 14 protrudes (negative electrode side end) is similarly formed on the connecting surface 45a. Gathered together.
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 axial direction of the electrode body 10 The thickness of the portion where the positive electrode sheet 12 was gathered at the end (the thickness of the portion welded to the connection surface 45a) was about 320 μm per location.
[0043]
The positive electrode sheet 12 collected on the connection surface 45a is ultrasonically welded to the connection surface 45a. At this time, as shown in FIG. 10, the anvil 72 is inserted into the space K between the connection surfaces 45a from the end surface of the electrode body 10, and the inner surface 45b of one wing 45 (located on the upper side in FIG. 10) is inserted. Place them in contact. Further, a horn 74 is arranged with the connecting surface 45a of the one wing portion 45 and the positive electrode sheet 12 gathered on the connecting surface 45a interposed therebetween. In this state, the positive electrode sheet 12 is fixed by welding to one wing portion 45 (connection surface 45a).
[0044]
Next, when the electrode body 10 is rotated halfway around its winding axis, the other wing part 45 (connection surface) is located at substantially the same position as the one wing part 45 (connection surface 45a) before the half rotation. 45a) is arranged. Therefore, with respect to the long side direction (vertical direction in FIG. 2) of the electrode body 10, the positive electrode sheet 12 which is bundled in two is moved without moving the positions of the anvil 72 and the horn 74. And it can weld to the other wing | blade part 45 one after another. In addition, although the case where the positive electrode side edge part of the electrode body 10 was welded (connected) to the current collection bar 40 was demonstrated here, the negative electrode side edge part of the electrode body 10 can also be welded by the same operation.
[0045]
When welding the remaining positive electrode sheet 12 to the other connection surface 45a after welding the positive electrode sheet 12 to one connection surface 45a of the current collecting bar 40, as shown in FIG. 10, the connection surface 45a side previously welded In addition, it is possible to perform welding by arranging the contact plate 76 from the outside of the welding portion. Thereby, the welding reliability (for example, welding strength) of the location welded previously can be improved. This method is particularly effective when the distance h1 (see FIG. 5) between the two connection surfaces is relatively close.
In addition to the method of sequentially welding the positive electrode sheet 12 to the two connection surfaces 45a of the current collector bar 40 as described above, the thickness of the anvil 72 is adjusted and the two horns 74 are used to provide two connection surfaces. The positive electrode sheet 12 may be welded to 45a at the same time. According to this method, productivity can be improved.
[0046]
In the connection structure of the present embodiment, as shown in FIG. 3, the electrode sheets 12 and 14 constituting the axial end portion of the electrode body 10 are from the central portion (winding inner peripheral portion) in the thickness direction of the electrode body 10. Divided into two and collected. Further, the gathered position is the central portion of the outer periphery and inner periphery of the electrode body 10. Thereby, compared with the structure (refer FIG. 13) which gathers the whole electrode sheets 12 and 14 which comprise the axial direction edge part of the electrode body 10 in one place of the thickness direction of the electrode body 10 (refer FIG. 13). Of these, the width of the current collector terminal connection can be reduced. Therefore, the mounting efficiency of the storage element can be improved. Moreover, since the electrode sheets 12 and 14 divided and gathered in this way are welded to the connection surface 45a, the thickness of the electrode sheets 12 and 14 welded to one place is reduced (as shown in FIG. 13). About half of that when gathered in one place in the thickness direction). This improves the welding reliability. This effect is particularly well exhibited when the number of turns of the electrode body is relatively large (for example, the number of turns is 40 or more).
[0047]
Thus, the electric double layer capacitor 1 can be manufactured from the electrode body 10 to which the current collector bar 40 is connected, for example, as follows.
As shown in FIG. 11, the electrode body 10 to which the current collector bar 40 is connected is accommodated sideways from the opening of the case 20 into the inside thereof. As shown in FIG. 12, the insulating member 50 is disposed from the opening of the case 20 so as to engage with the external terminal connecting portion 44 of the current collecting bar 40. Next, the lid 30 is attached to the opening of the case 20. At this time, the current collecting cylindrical portion 46 and a portion of the insulating member 50 covering the outer periphery thereof are inserted into the terminal mounting hole 32. And the electrical storage element intermediate body 3 with which case 20 was sealed (canned) by the lid body 30 is formed by joining the opening part of the case 20 and the peripheral part of the lid body 30 by laser welding or the like.
[0048]
As shown in FIG. 12, a communication path P that connects the inside and the outside of the electricity storage element structure 3 is formed by a current collecting cylindrical portion 46 inserted into the terminal mounting hole 32. The electrolytic solution is injected into the electric storage element structure 3 from the communication path P. Here, propylene carbonate (containing 0.5 mol / liter of tetraethylammonium tetrafluoroborate) was used as the electrolytic solution.
After that, as shown in FIG. 1, the insulating packing 24 is disposed around the terminal mounting hole 32 from the top of the lid 30. Next, the leg portion 64 of the external terminal 60 is screwed to the current collecting cylindrical portion 46. At this time, when the insulating member 50 abuts against the inner wall of the case 20, the external terminal connection portion 44 is prevented 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 current collecting bar 40, and the communication path P (see FIG. 12) formed in the current collecting cylindrical portion 46 was closed.
[0049]
In addition, an electrolyte injection port (through hole; not shown) is formed in the lid 30 or a part of the case 20 separately from the terminal mounting hole 32, and the inside of the electricity storage device intermediate 3 is formed from the electrolyte injection port. An electrolyte may be injected into the liquid crystal. In this case, the electrolyte injection port may be closed by a sealing member or the like different from the external terminal 60 in any of the subsequent steps.
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 current collector bar 40 is connected from above the case 20. can do.
[0050]
(Second embodiment)
The present 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 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0051]
As shown in FIG. 14, the current collecting bar 40 constituting the capacitor of this example is wound from the end face of the flat electrode body 10 in this order from the bottom (here, the end face at the end portion on the negative electrode side is shown). The flat sheet connecting portion 42 inserted into the inner peripheral portion, the flat plate extending portion 14 extending from the sheet connecting portion 42 along the end face of the electrode body 10 in the long side direction, and the upper end of the extracting portion 14 are substantially perpendicular to each other. An external terminal connection portion 44 formed by bending is formed. Since the shape of the current collecting bar 40 having such a shape is relatively simple, the current collecting bar 40 can be easily manufactured, for example, by bending (typically pressing) a single metal plate.
[0052]
As shown in FIG. 15, the front surface (connection surface) 42 a and the back surface (connection surface) 42 b of the sheet connection 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. Further, the negative electrode sheet 14 is gathered (pushed out) from the inner peripheral side to the outer peripheral side depending on the thickness (plate thickness) of the sheet connecting portion 42. In this way, the negative electrode sheet 14 is gathered between both the outer peripheral side and the inner peripheral side, and connected (for example, by ultrasonic welding) on the connection surfaces 42a and 42b. In addition, the current collection bar 40 is similarly connected to the positive electrode side end part (not shown) of the electrode body 10.
[0053]
As shown in FIG. 14, the external terminal connecting portion 44 is provided with a through hole 47. The lower end of the external terminal 60 is connected to the through hole 47 through the lid 30. At this time, by disposing the insulating packing 24 between the external terminal 60 and the lid 30, both are insulated and hermetically 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 accommodating this in the case 20 (see FIG. 1) together with the electrolyte and sealing it.
[0054]
In the configuration of this example, the negative electrode sheet 14 constituting the axial end portion of the electrode body 10 was divided and collected on both sides in the thickness direction with the winding inner peripheral portion of the electrode body 10 as a boundary. Each of the portions are gathered and welded to the connection surfaces 42a and 42b. Therefore, welding reliability can be improved compared with the structure etc. which gather the negative electrode sheet 14 in the one place from the whole thickness direction. Further, even when the number of windings is increased, good connectivity can be obtained, so that the degree of freedom in designing the electrode body can be increased. Since the negative electrode sheet 14 is gathered between them from both the outer peripheral side and the inner peripheral side of the electrode body 10, the width of the current collector terminal connection portion is made wider than the configuration in which the negative electrode sheet 14 is gathered in one place. Can be small. Therefore, the mounting efficiency of the capacitor can be improved. The thickness of the sheet connecting portion 41 (that is, the interval h1 between the connecting surface 42a and the connecting surface 42b; see FIG. 15) is preferably approximately half the thickness of the electrode body 10. Moreover, it is preferable that the negative electrode sheet 14 is gathered in the center part of the outer periphery and inner periphery of the electrode body 10. In such a case, the effect of reducing the width of the current collector terminal connection portion is particularly great.
[0055]
The present embodiment is preferably applied to a capacitor having a relatively thin electrode body. Although not particularly limited, the thickness of the sheet connecting portion can be, for example, in the range of about 0.5 to 5 mm, the preferable thickness is in the range of about 1 to 3 mm, and the more preferable thickness is in the range of about 1.5 to 5 mm. The range is 2.5 mm.
[0056]
(Third embodiment)
The present embodiment relates to a capacitor configured by using a current collecting bar having a sheet connecting portion having a shape different from that of the second embodiment.
[0057]
As shown in FIGS. 16 and 17, the bent sheet-like sheet connecting portion 42 is inserted into the winding inner peripheral portion of the electrode body 10. The lower part of the sheet connection part 42 is biased toward one side (left side in FIG. 17) of the thickness of the electrode body 10 and constitutes a flat plate-shaped first unevenly distributed part 421 substantially perpendicular to the thickness direction. Further, the upper portion of the sheet connecting portion 42 is biased toward the other side of the thickness of the electrode body 10 (the right side in FIG. 17), and constitutes a flat plate-like second unevenly distributed portion 422 substantially perpendicular to the thickness direction. The shape of the other part of the current collecting bar 40 is substantially the same as 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 in the same manner as the current collecting bar 40 used in the second embodiment. it can. Therefore, for example, the cost can be reduced as compared with the case where the current collecting bar is manufactured by cutting metal.
[0058]
As shown in FIG. 17, the negative electrode sheet 14 is gathered together on the surface (connection surface) 42 a closer to the negative electrode sheet 14 (protrusion side) in the first unevenly distributed portion 421. Further, the negative electrode sheet 14 is gathered together on the surface (connection surface) 42 b closer to the negative electrode sheet 14 (projecting side) in the second unevenly distributed portion 422. 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 positions of the connection surfaces 42a and 42b are also in the long side direction. (Displaced vertically). In addition, since the sheet connection portion 42 is bent, a space opened on the end surface of the electrode body 10 is formed between the sheet connection portion 42 and the inner periphery of the negative electrode sheet 14 on the back side of the connection surfaces 42a and 42b. K is formed.
[0059]
According to such a configuration, the negative electrode sheet 14 gathered on the two connection surfaces 42a and 42b can be welded at a time using the two sets of the anvil 72 and the horn 74. For example, as shown in FIG. 17, two anvils 72 are respectively inserted from the end surfaces of the electrode bodies into the spaces K formed on the back surfaces of the connection surfaces 42a and 42b. Between the anvil 74 and the horn 74, the negative electrode sheet 14 collected on the first unevenly distributed portion 421 and its connecting surface 42a, and the negative electrode collected on the second unevenly distributed portion 422 and its connecting surface 42b. What is necessary is just to ultrasonically weld the sheet | seat 14 at once across each. The current collector bar 40 can be similarly connected to the positive electrode side end portion (not shown) of the electrode body 10.
[0060]
In this embodiment, since the connection surfaces 42a and 42b are displaced in the long side direction (up and down) in the cross section of the electrode body, the two sets of anvils 72 and horns 74 can be arranged without buffering each other during welding. . As a result, the negative electrode sheets 14 gathered on the respective connection surfaces can be welded to the two connection surfaces 42a and 42b at a time. Moreover, you may weld the negative electrode sheet 14 to these connection surfaces 42a and 42b separately (sequentially). For example, the negative electrode sheet 14 may be connected to the connection surface 42b after the negative electrode sheet 14 is connected to the connection surface 42a. In addition, it is preferable that the space | interval h1 (refer FIG. 17) of the connection surface 42a and the connection surface 42b is a half of the thickness of the electrode body 10. FIG.
[0061]
(Fourth embodiment)
This embodiment relates to a capacitor formed by connecting an electrode sheet to a side end surface of a plate-like sheet connecting portion.
[0062]
As shown in FIGS. 18 and 19, a flat sheet connecting portion 42 is formed at the lower end of the current collecting bar 40. The sheet connection portion 42 has both end faces (connection faces) 42a and 42b facing outward in the thickness direction of the electrode body 10, and the positive end face (left end in FIG. 18) and the negative end face (FIG. 18). Is inserted into the inner circumference of the winding. As shown in FIG. 18, the lead-out portion 41 that is provided above the sheet connection portion 42 extends along the long side direction along the end surface of the electrode body 10.
[0063]
As shown in FIG. 19, a concave portion 48a is formed on the back side of the connection surface 42a (on the connection surface 42b side) at the upper portion of the sheet connection portion 42. In addition, a recess 48b is formed in the lower portion of the sheet connecting portion 42 on the back side (the connecting surface 42a side) of the connecting surface 42b. As described above, a part of the sheet connecting portion 42 is notched to form the recesses 48a and 48b, so that a space K that opens to the end surface of the electrode body 10 is formed on the back side of the connecting surfaces 42a and 42b. Is formed. Since the current collecting bar 40 having such a shape is relatively simple, the current collecting bar 40 can be easily manufactured by bending (typically pressing) a single metal plate.
[0064]
According to such a configuration, as in the third embodiment, the electrode sheets 12 and 14 gathered together on the two connection surfaces 42a and 42b are welded at a time using the two sets of the anvil 72 and the horn 74. Can do. In addition, it is preferable that the width | variety (namely, space | interval h1 of the connection surface 42a and the connection surface 42b; refer FIG. 19) of the sheet | seat connection part 42 is substantially half of the thickness of the electrode body 10. FIG.
[0065]
(Fifth embodiment)
The present embodiment relates to a capacitor configured using a current collecting bar having a shape different from that of the fourth embodiment.
[0066]
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 following the upper end thereof. The entire 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 substantially similar to that of the fourth embodiment is inserted. Moreover, as shown in FIG. 20, the part which comprises the upper part of the electrode body 10 is cut off in the positive electrode sheet 12 and the negative electrode sheet 14 which comprise the both ends of the electrode body 10. FIG. This avoids buffering with the drawer portion 41 extending substantially straight upward after the seat connecting portion 42.
[0067]
Since the current collector bar 40 of this embodiment is linear in shape and simple in shape, it can be easily manufactured from a single metal plate by punching, pressing, or the like. Moreover, since the current collection bar 40 can be accommodated inside the axial direction length of the electrode body 10, the space efficiency inside the container 2 (refer FIG. 1) can be improved.
[0068]
Although the electric double layer capacitor and the manufacturing method thereof have been described in the above embodiments, the present invention may be applied to other types of batteries such as lithium ion secondary batteries, nickel hydrogen batteries, nickel cadmium batteries (primary batteries or secondary batteries). ), Capacitors other than electric double layer capacitors, and other power storage elements. The materials of the positive and negative electrode active materials, current collector sheets, separators, current collector bars, external terminals, power storage element containers, and the like, the composition of the electrolyte, and the like are appropriately selected according to the type of power storage element.
Note that the idea of the present invention is not limited to a power storage element including a wound electrode body, and can also be applied to a power storage element including a stacked electrode body.
[0069]
Further, as a technical matter grasped from the description of the present specification, a sheet connecting portion having two connecting surfaces is inserted into the winding inner peripheral portion from the axial end portion of the electrode body wound in a flat shape. And an electricity storage element in which electrode sheets gathered from the outer peripheral side or the inner peripheral side at two locations in the circumferential direction of the electrode body are connected 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 from the outer peripheral side and the inner peripheral side. Moreover, the gathered location may be between the outer periphery and the inner periphery of the electrode body, and may not be between the outer periphery and the inner periphery. According to the electricity storage device having such a configuration, the electrode sheet constituting the axial end portion of the electrode body is divided into two in the thickness direction from the winding inner peripheral portion of the electrode body, and each electrode sheet is gathered. Compared with the structure etc. gathered together, welding reliability with a sheet | seat connection part can be improved. Further, even when the number of windings is increased, good connectivity can be obtained, so that the degree of freedom in design can be increased.
[0070]
Specific examples of the present invention have been described in detail above, 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.
In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an electric double layer capacitor according to a first embodiment.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a cross-sectional view taken along line III-III in FIG.
FIG. 4 is a cross-sectional view showing an example of a current collecting bar having a different shape of a sheet connecting portion.
5 is a partially enlarged view of FIG. 3;
FIG. 6 is a plan view showing a positive electrode sheet constituting 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 cylindrical shape.
FIG. 9 is a side view showing a process of collecting the electrode sheets on the connection surface.
FIG. 10 is a cross-sectional view showing a process of welding an electrode sheet to a connection surface.
FIG. 11 is a cross-sectional view showing a state where an electrode body to which a current collector bar is connected is housed in a case in the manufacturing process of the electric double layer capacitor according to the first embodiment.
FIG. 12 is a cross-sectional view showing a state where a case is sealed to constitute an energy storage element intermediate body in the manufacturing process of the electric double layer capacitor according to the first embodiment.
FIG. 13 is a cross-sectional view schematically showing an example of a current collecting structure of a conventional power storage element.
FIG. 14 is an exploded perspective view showing a connection structure of current collector bars, electrode bodies and external terminals in an electric double layer capacitor according to a second embodiment.
15 is a cross-sectional view of the electrode body connected to the current collector bar taken along line XV-XV in FIG.
FIG. 16 is an exploded perspective view showing a connection structure of current collector bars, electrode bodies, and external terminals in an electric double layer capacitor according to a third embodiment.
17 is a cross-sectional view of the electrode body connected to the current collector bar taken along line XVII-XVII in FIG.
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 taken in the direction of the arrow XIX in FIG.
FIG. 20 is a side view showing an electrode body and a current collecting bar of an electric double layer capacitor according to a fifth embodiment.
21 is a view in the direction of arrows XXI-XXI in FIG.
[Explanation of symbols]
1: Electric double layer capacitor (storage element)
10: Electrode body
12: Positive electrode sheet
14: Negative electrode sheet
16: Separator
2: Storage element container
40: current collector bar (current collector terminal)
42: Seat connection part
42a, 42b: connection surface
44: External terminal connection
45: Wings
45a: Connection surface
48a, 48b: recess
60: External terminal
72: Anvil
74: Horn
K: space opened in the end face of the electrode body
H: Thickness of electrode body
h1: Connection surface spacing

Claims (4)

A flat electrode body in which a positive electrode sheet and a negative electrode sheet are wound in a flat shape via a separator, and a current collector terminal connected to an axial end of the electrode body,
The current collector terminal is formed with a plate-like sheet connection portion having two flat connection surfaces,
The sheet connecting portion is inserted only from the end of the electrode body in the axial direction into the winding inner peripheral portion of the electrode body, and the two connection surfaces of the sheet connecting portion are respectively on one side in the thickness direction of the electrode body. It faces the thickness direction outside of the electrode body at a biased position and a biased position on the other side,
Positive or negative electrode sheet constituting the axial end portion is an outer peripheral brought together from both the outer peripheral side and inner peripheral side over the entire layer to the inner circumference of the circumferential direction of the two points of the electrode body And each of the gathered points is welded to each of the two connecting surfaces,
An electrical storage element characterized in that a space that opens to an end surface of the electrode body is formed on the back side of a portion where the electrode sheets gathered from the inner peripheral side toward the outer peripheral side are welded to the connection surface . The sheet connecting portion is formed of a plate material bent in a U-shape, and a space that opens to an end surface of the electrode body is formed between the two connecting surfaces. Item 1. The electricity storage device according to Item 1. The sheet connecting portion is a bent plate shape, and a portion biased to one side in the thickness direction of the electrode body and a portion biased to the other side due to the bending are in a long side direction at an axial end portion of the electrode body. It is formed by shifting the positions from each other along the, according to claim 1, wherein the two connection surfaces at the surfaces of the respective projecting side portions biased on one part and the other side biased to the side is formed Power storage element. The electrical storage element according to any one of claims 1 to 3 , wherein a distance between the two connection surfaces is approximately half of a thickness of the electrode body.

Images