JP2002056886A - Battery or capacitor and method for manufacturing the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a battery / capacitor that is a current collector by bundling the respective edges at both ends of a wound body, there is little protrusion on the inner peripheral side of the current collector, and the current collector material is effective. The present invention provides a battery or a capacitor that can be used for a battery and a method for manufacturing the same. SOLUTION: The battery or capacitor of the present invention has a positive electrode widened portion 11 whose width increases from one end to the other end in the longitudinal direction.
1a having positive electrode current collector 1a and positive electrode current collector 1
And a positive electrode sheet 11 composed of a positive electrode active material layer 112 formed on the first electrode 11 and one end to the other end in the longitudinal direction.
A negative electrode current collector 121 having a negative electrode widened portion 121a that is widened on the opposite side to the positive electrode widened portion 111a and a negative electrode sheet 12 composed of a negative electrode active material layer 122 formed on the negative electrode current collector 121 are wound. It is characterized in that the positive electrode widened portion 111a and the negative electrode widened portion 121a are pressed against each other at both ends of the wound body to form current collectors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery or a capacitor and a method of manufacturing the same, and more particularly, to a battery or a capacitor obtained by pressing both ends of a wound body formed by winding a positive electrode sheet and a negative electrode sheet. And a method for producing the same.

[0002]

2. Description of the Related Art A wound type battery or capacitor (hereinafter referred to as "battery / capacitor") is formed by winding a long positive electrode sheet and a negative electrode sheet and a separator disposed between the two electrode sheets. Is also known.)). Japanese Patent Application Laid-Open No. 10-55936 discloses that the active material is not applied to one edge in the longitudinal direction of both electrode sheets, these electrode sheets are wound together with a separator, and the edge on the positive electrode side is formed. There is disclosed an electric double-layer capacitor in which a wound body in which an edge on the negative electrode side is located at both ends is formed, and the edges are bundled at both ends of the wound body to serve as a current collecting terminal.

[0003]

As shown in FIG. 5, the positive electrode sheet 9 used in the prior art is used.
1. Each of the negative electrode sheet 92 and the separator 93 has a constant width in any portion in the longitudinal direction.
This positive electrode side electrode sheet 91 is formed by forming a positive electrode active material layer 912 in a portion of the positive electrode current collector 911 excluding the peripheral portion 911a. Further, the negative electrode sheet 92 is formed by forming the negative electrode active material layer 922 in a portion of the negative electrode current collector 921 except for the peripheral portion 921a. The width of the separator 93 sandwiched between the two electrode sheets is substantially equal to the width of a portion of the two electrode sheets where the positive electrode active material 912 and the negative electrode active material 922 are applied. The edge 9 of the positive electrode sheet 91 is also provided.
1a and the edge portion 92a of the negative electrode sheet 92 are arranged on opposite sides of the width direction of both electrode sheets.

The positive electrode sheet 91, the negative electrode sheet 92 and the separator 93 are wound as shown in FIG. 6 to form a wound body 9. Both ends (upper and lower ends in FIG. 6) of the wound body 9 are formed. When each is pressed, as shown in FIG. 7, the current collectors on the inner peripheral side protrude from the end faces of the current collectors 9a and 9b formed by the press contact as compared with the outer peripheral side. 6 and 7, the active material is not shown. The protrusion is not suitable as a mounting portion for the current collecting terminal 8 and hinders miniaturization of the battery / capacitor.
Japanese Patent Publication No. 936 describes that it is preferable to cut and align the end faces. For example, it is presumed that the cutting is performed at a position indicated by a dotted line C shown in FIG. However, when the protruding portion is cut in this way, the number of manufacturing steps of the battery / capacitor increases, and chips generated at the time of cutting may be mixed into the wound body or the like, thereby lowering the reliability of the battery / capacitor. . Further, there is also a problem that the material cost is increased because the current collector material in the portion constituting the protrusion is wasted.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery / capacitor having a current collector formed by bundling the respective edges at both ends of a wound body. It is an object of the present invention to provide a battery / capacitor and a method for manufacturing the same, which can be used for a battery.

[0006]

According to another aspect of the present invention, there is provided a battery or a capacitor according to claim 1, wherein the width of the positive electrode is increased from one end to the other end in one longitudinal direction. A positive electrode current sheet having a positive electrode and a positive electrode sheet made of a positive electrode active material layer formed on the positive electrode current collector except for the positive electrode widened portion, and one edge in the longitudinal direction from one end in the longitudinal direction. A negative electrode current collector having a negative electrode widened portion that extends toward the other end and a negative electrode sheet made of a negative electrode active material layer formed on the negative electrode current collector except for the negative electrode widened portion, A battery or a capacitor that is wound with one end being a center side, and the positive electrode widened portion and the negative electrode widened portion are pressed against each other at both ends of the wound body to form a current collecting portion, wherein the width of the positive electrode widened portion and the negative electrode The width of the widening part is Serial to the positive electrode side electrode sheet and the width direction of the negative electrode side electrode sheet, characterized in that it extends to the opposite side to each other.

A battery or a capacitor according to claim 2 is
2. The battery or capacitor according to claim 1, wherein the width of the positive electrode widened portion and the width of the negative electrode widened portion are such that the end surfaces of the positive electrode widened portion and the negative electrode widened portion at the both ends of the wound body during the pressure contact are formed. It is characterized by being spread out so as to be aligned.

According to a third aspect of the present invention, there is provided a method of manufacturing a battery or a capacitor according to the first or second aspect, wherein the positive electrode sheet, the negative electrode sheet, and a separator are wound. At both ends, the positive electrode widened portion and the negative electrode widened portion are respectively pressed into contact with each other to form a current collector.

The current collectors constituting the positive electrode sheet and the negative electrode sheet include aluminum foil,
Metal foils such as nickel foil and copper foil are preferably used. The thickness of the current collector is usually about 5 to 100 μm, and the length and average width can be appropriately set according to the shape and performance of the battery / capacitor. The widths of the positive electrode widening portion and the negative electrode widening portion gradually or gradually increase from one end in the longitudinal direction to the other end. Here, "one end in the longitudinal direction" is a winding start side when manufacturing a wound body,
The “other end in the longitudinal direction” is the end of winding, and after winding, this one end constitutes the central portion of the wound body and the other end constitutes the outer peripheral portion. The width of the widened portion at one end in the longitudinal direction is, for example, about the height of the current collector formed by pressure welding (the length of the current collector with respect to the width direction of the current collector), or 1.0 to 1.0 of this height. It can be about 1.5 times. The width of the widened portion may be linear or curved, but when the widened portion is pressed into contact after winding the electrode sheet, the end faces of the widened portion are aligned in at least a partial range as shown in FIG. Such a spreading condition is preferable. Further, in order to reduce the number of metal foils at the ends when cutting out the current collector for each electrode from the metal foil of the raw material, it is preferable that the width of the widened portion is linearly widened from one end to the other end.

The active material layer is usually composed of an active material, a binder and, if necessary, a conductive material and the like, and is formed by applying a paste containing the above components and a solvent on the current collector. A method such as drying is used. The types of the active material, the binder, and the solvent to be contained in the paste may be appropriately selected depending on the type of the battery / capacitor and whether the electrode is positive or negative. For example, when this active material layer is applied to an electrode of a lithium ion secondary battery, LiC is used as a positive electrode active material.
It is possible to employ oO ₂ powder or the like, a carbon material (pitch coke) powder or the like as a negative electrode active material, polyvinylidene fluoride or the like as a binder, and N-methylpyrrolidone or the like as a solvent. When this active material layer is applied to an electrode of an electric double layer capacitor, for example, activated carbon or the like as a positive or negative electrode active material, methylcellulose, polytetrafluoroethylene, polyvinylidene fluoride, or the like as a binder, Water, N-methylpyrrolidone, or the like can be used as the solvent. The active material layer may be formed on all of the current collector except for the widened portion, or may be formed on a part of this portion. Further, it may be formed only on one surface of the current collector, or may be formed on both front and back surfaces.

The separator is interposed between the positive electrode and the negative electrode in the wound body to prevent a short circuit of the electrode and to hold the electrolyte, and is appropriately selected from conventionally known porous thin films and the like. Can be used. Further, a porous resin layer or the like may be formed on one or both surfaces of the positive electrode sheet and / or the negative electrode sheet to form an electrode-integrated separator. Generally, it is preferable that the width and length of the separator be substantially equal to the width and length of the positive electrode active material and the negative electrode active material.

The positive electrode sheet, the negative electrode sheet, and the separator are laminated so that the positive electrode widened portion and the negative electrode widened portion protrude from both sides in the width direction of the separator, respectively, from one end in the longitudinal direction to the other end. By winding up, a wound body is obtained. Both ends (corresponding to both ends in the width direction of both electrode sheets) of the wound body have a shape in which the inner peripheral side is depressed as compared with the outer peripheral side due to the shapes of the positive electrode widened portion and the negative electrode widened portion. As described above, since the inner peripheral side of the wound body is dented before the pressure contact, in the current collecting portion formed by the pressure contact, it is possible to suppress the protrusion of the central portion as compared with the conventional case, and under preferable conditions, the positive electrode widening portion and The end faces of the negative electrode widening portion can be aligned. This current collector is electrically connected to an external terminal of the battery / capacitor. For example, a current collecting terminal such as a metal rod can be welded to the current collecting portion and connected to an external terminal via the current collecting terminal.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically by way of examples. 2 to 4, the active material layer is omitted. As shown in FIG. 1, the positive electrode sheet 11
Is a positive electrode current collector 111 made of aluminum foil having a thickness of 15 μm × length 5.13 m, and a positive electrode active material layer 112 formed in a rectangular portion having a width of 86 mm in the positive electrode current collector 111.
Consists of The thickness of the positive electrode sheet 11 at the portion where the active material layer is formed is 87 μm. Further, the negative electrode sheet 12 has a negative electrode current collector 121 made of a copper foil having a thickness of 10 μm × length 5.13 m, and a width 8 of the negative electrode current collector 121.
And a negative electrode active material layer 122 formed in a 6 mm rectangular portion. The thickness of the negative electrode sheet 12 at the portion where the active material layer is formed is 58 μm. Each of the positive electrode current collector 111 and the negative electrode current collector 121 has a positive-electrode widening portion 111a and a negative-electrode widening portion 121a that linearly expand in width from one end to the other end in the longitudinal direction at one edge in the longitudinal direction. Positive electrode widening section 111a and negative electrode widening section 121a
Are 11 mm at one end in the longitudinal direction and 14 mm at the other end, and no active material layer is formed in this portion. The separator 13 has a rectangular shape with a width of 86 mm and a length of 5.13 m, and is made of polyethylene having a thickness of 25 μm.

The positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 are separated from the position where the positive electrode active material layer 112 and the negative electrode active material layer 122 are formed and the separator 1.
3 and the positive electrode widened portion 111a protrudes from one of the width directions of the separator 13 (upper end in FIG. 1), and the negative electrode widened portion 121a protrudes from the other in the width direction of the separator 13 (lower end in FIG. 1). Were laminated as follows. That is, the width of the positive electrode widened portion 111a and the width of the negative electrode widened portion 121a
Are spread on opposite sides of the width direction of the electrode sheet. This laminated product was wound (35 turns) in an oval cross section from one end (the left end in FIG. 1) in the longitudinal direction to the other end. FIG. 2 is a cross-sectional view of the obtained wound body 1 taken along the long axis of the oval shape, and FIG. 2 is a cross-sectional view of the obtained wound body 1 taken along the short axis (that is, a cross-sectional view taken along line III-III of FIG. 2). As shown in FIG. Due to the shapes of the positive electrode widened portion 111a and the negative electrode widened portion 121a, the widened portions at both ends (upper and lower ends in FIG. 2) of the wound body 1 gradually decrease from the outer peripheral side to the inner peripheral side of the wound body 1. I have.

When the positive-electrode widened portion 111a located at the upper end of the wound body 1 and the negative-electrode widened portion 121a located at the lower end are pressed against each other from the left and right directions in FIG. 3, the inner peripheral side is lowered before the pressure contact. As a result, as shown in FIG. 4, the positive electrode current collector 1a and the negative electrode current collector 1
b, the positive electrode widened portion 111a and the negative electrode widened portion 12a
The end faces of 1a are aligned. Therefore, there is no need to cut the current collector in order to align the end faces of the positive electrode current collector 1a and the negative electrode current collector 1b. Thus, the size of the battery can be reduced without increasing the number of cutting steps, and mixing of chips can be avoided. Then, the positive current collecting terminal 2 made of aluminum is added to the positive current collecting portion 1a and the negative current collecting portion 1b.
a and the negative electrode current collecting terminal 2b made of copper are welded, respectively, and housed together with the electrolytic solution in an outer container (neither is shown) to constitute a battery.

[0016]

According to the battery / capacitor of the present invention and the method of manufacturing the same, a current collector having a widened portion that widens from the winding start side to the winding end side is used as the electrode sheet in the wound type battery / capacitor. Thus, when the electrode sheet is wound and the widened portion is pressed, the end faces of the current collector formed by the pressure contact can be made uniform or at least the protrusion can be suppressed. Therefore, the size of the battery can be reduced without cutting the current collector, and the entry of chips can be avoided. According to the present invention, even when the end faces of the current collecting unit are not completely aligned after the pressure welding, the degree of protrusion is reduced as compared with the related art, which is advantageous for downsizing the battery. Further, even when the current collector is cut and the end faces are aligned, the cut portion is smaller than in the conventional case, so that waste of the current collector material can be suppressed.

[Brief description of the drawings]

FIG. 1 is a plan view showing shapes and arrangements of an electrode sheet and a separator before winding in a battery of an example.

FIG. 2 is a schematic cross-sectional view showing a cross section along a long axis of a wound body before both ends are pressed against each other in a battery of an example.

FIG. 3 is a schematic cross-sectional view showing a cross section along a short axis of a wound body before both ends are pressed against each other in the battery of the embodiment, and is a cross-sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a schematic cross-sectional view showing a cross section along a short axis of a wound body after both ends are pressed against each other in the battery of the embodiment.

FIG. 5 is a plan view showing shapes and arrangements of an electrode sheet and a separator before winding in a conventional battery / capacitor.

FIG. 6 is a schematic cross-sectional view showing a wound body before both ends of the conventional battery / capacitor are pressed against each other.

FIG. 7 is a schematic cross-sectional view showing a wound body after both ends are pressed against each other in a conventional battery / capacitor.

[Explanation of symbols]

1; wound body, 1a; positive electrode current collector (current collector), 1b; negative electrode current collector (current collector), 11; positive electrode sheet, 111;
Positive electrode current collector, 111a; positive electrode widened portion, 112; positive electrode active material layer, 12; negative electrode sheet, 121; negative electrode current collector,
121a; negative electrode widening portion, 122; negative electrode active material layer, 13;
Separator, 2a; Positive current collecting terminal, 2b; Negative current collecting terminal.

Claims (3)

[Claims] 1. A positive electrode current collector having a positive electrode widened portion extending from one end to the other end in the longitudinal direction at one edge in the longitudinal direction, and formed on the positive electrode current collector except for the positive electrode widened portion. Except for the negative electrode current collector and the negative electrode widened portion having a positive electrode side electrode sheet made of the formed positive electrode active material layer, and a negative electrode widened portion having a width extending from one end to the other end in the longitudinal direction at one edge in the longitudinal direction. And a negative electrode sheet made of a negative electrode active material layer formed on the negative electrode current collector, and wound around one end in the longitudinal direction as the center side, and at both ends of the wound body, the positive electrode widened portion and the negative electrode A battery or capacitor in which the widened portions are pressed into contact with each other as a current collecting portion, wherein the width of the positive electrode widened portion and the width of the negative electrode widened portion are in the width direction of the positive electrode sheet and the negative electrode sheet. , Extend to opposite sides Battery or capacitor, characterized in that it Tsu. 2. The width of the widened portion of the positive electrode and the widened portion of the negative electrode are increased such that the end faces of the widened portion of the positive electrode and the widened portion of the negative electrode are aligned at both ends of the wound body during the pressing. The battery or capacitor according to claim 1, wherein 3. The method for producing a battery or a capacitor according to claim 1, wherein the positive electrode sheet, the negative electrode sheet, and a separator are wound,
A method for manufacturing a battery or a capacitor, characterized in that the positive electrode widened portion and the negative electrode widened portion are pressed against each other at both ends of the wound body to form a current collector.