JP7272861B2 - Wound energy storage device and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a wound electricity storage device and a manufacturing method thereof.

Conventionally, as a winding-type electricity storage device, for example, a capacitor element is formed by winding a winding body formed by winding an anode foil and a cathode foil made of aluminum foil with a separator made of electrolytic paper interposed therebetween with an element fixing tape. An electrolytic capacitor is known in which the capacitor element is impregnated with a driving electrolytic solution or solid electrolyte and then housed in a case, or the capacitor element is housed in a case and then impregnated with an electrolyte (see Patent Document 1). ).

FIG. 8 is an explanatory diagram showing components of a conventional capacitor element 101. As shown in FIG. As shown in FIG. 8 , capacitor element 101 has anode foil 102 , cathode foil 103 , separators 104 a and 104 b , anode terminal 105 , cathode terminal 106 and element fixing tape 107 .

Capacitor element 101 shown in FIG. 8 has anode foil 102, separator 104a, cathode foil 103, and separator 104b stacked in this order and wound so that anode foil 102 faces inside. After forming a cylindrical body (wound body) by further winding it with the

JP 2016-12622 A

By the way, the anode foil and the cathode foil of an electrolytic capacitor are obtained by cutting a strip-shaped electrode foil to a predetermined length. . As a result, the anode foil and the cathode foil are electrically connected to each other, which may cause a short-circuit failure.

FIG. 9 is a plan view showing how anode foil 102, separator 104a, cathode foil 103, and separator 104b are wound in capacitor element 101. As shown in FIG. FIG. 10 is a cross-sectional view of the vicinity of the end portion of anode foil 102 .

As shown in FIGS. 9 and 10, the thickness of the anode foil 102 causes a step on the separator 104a at the terminal end of the anode foil 102. As shown in FIGS. Here, when the cut burr A is generated at the end portion of the anode foil 102, and the cut burr A is relatively sharp and is oriented substantially perpendicularly to the foil surface of the anode foil 102, the element fixing tape Due to the pressure applied to the surface of the wound body when winding 107 , there is a risk that the tip of the cut burr A will break through the separator 104 a and come into contact with the cathode foil 103 . In addition, when the electrolytic capacitor is charged, the anode foil 102 and the cathode foil 103 expand, which may cause the tip of the cut barrier A to pierce the separator 104a and come into contact with the cathode foil 103 .

Therefore, it is conceivable to remove cut burrs before the anode foil 102 and the cathode foil 103 are wound. However, not only is a cut burr removing process additionally required, but there is also a possibility that new burrs may be generated by performing the process of removing the cut burrs in the first place.

The present invention has been made in view of the above problems, and can prevent the occurrence of a short-circuit state due to contact between the anode foil and the cathode foil caused by cut burrs in at least one of the anode foil and the cathode foil. It is an object of the present invention to provide a wound electricity storage device and a method for manufacturing the same.

In order to achieve the above object, the present invention has the configuration described below.

(1) A wound energy storage device comprising an energy storage element and a case in which the energy storage element is housed,
The electric storage element includes a winding body obtained by winding a first electrode foil that is one of an anode and a cathode and a second electrode foil that is the other with a separator interposed therebetween, and a winding body wound around the circumference of the winding body. and has an element-stopping tape that maintains the wound state of the wound body,
A roll-type electricity storage device, wherein a leading end of the element-fixing tape is attached so as to be positioned between the first electrode foil and the second electrode foil.

(2) In (1), the starting end of the element-fixing tape is the radially outer terminal portion of the first electrode foil or the second electrode foil, which is arranged radially inward in the wound body. 2. The winding-type electric storage device according to claim 1, wherein the winding-type electric storage device is attached so as to overlap with the .

(3) a cutting step of cutting the electrode foil material to form a first electrode foil that will be one of the anode and the cathode and a second electrode foil that will be the other;
a winding step of overlapping the first electrode foil and the second electrode foil with a separator interposed therebetween and winding them from the starting end to the terminal end to form a wound body;
an element-fixing step of winding an element-fixing tape having an adhesive surface on one side and a non-adhesive surface on the other side around the outer peripheral surface of the wound body. A method for manufacturing a storage battery device,
A method for manufacturing a wound electrical storage device, wherein in the element-fixing step, the starting end of the element-fixing tape is attached so as to be positioned between the first electrode foil and the second electrode foil. .

(4) In (3), in the winding step, the warping of the end portion of the first electrode foil generated in the cutting step in the radially inner side of the wound body is the winding step. It is arranged so as to face the outside of the round body,
A method for manufacturing a wound electric storage device, wherein in the element-fixing step, the starting end of the element-fixing tape is adhered so as to overlap the radially outer end of the first electrode foil.

According to the present invention having the configurations of (1) to (4), the warp (so-called cut burr) portion at the terminal end of the first electrode foil (for example, the anode foil) is covered with the starting end of the element fixing tape. Since the starting end of the element-fixing tape is stuck between the first electrode foil and the second electrode foil, the end of the anode foil breaks through the separator to reach the second electrode foil (e.g., the cathode). It is possible to prevent the occurrence of a short-circuit state due to contact between the anode foil and the cathode foil caused by cut burrs.

According to the present invention, it is possible to prevent occurrence of a short-circuit state due to contact between the anode foil and the cathode foil caused by cut burrs in at least one of the anode foil and the cathode foil.

1 is a front view showing the appearance of an electrolytic capacitor 1 according to one embodiment of the present invention; FIG. 1 is an exploded view showing constituent parts of an electrolytic capacitor 1 according to an embodiment of the present invention; FIG. FIG. 2 is an explanatory diagram showing constituent parts of a capacitor element 10 according to one embodiment of the present invention; FIG. 2 is a flowchart showing manufacturing steps of the electrolytic capacitor 1 in one embodiment of the present invention; FIG. 4 is an explanatory diagram showing a method of assembling the capacitor element 10 according to one embodiment of the present invention; 2 is a cross-sectional view showing the configuration of capacitor element 10 in the vicinity of an end portion of anode foil 2. FIG. 1 is a plan view showing a winding mode of a capacitor element 10 according to an embodiment of the invention; FIG. FIG. 4 is an explanatory diagram showing constituent parts of a conventional capacitor element 101; FIG. 3 is a plan view showing a winding state of a conventional capacitor element 101; FIG. 4 is a cross-sectional view showing the vicinity of the end portion of anode foil 102 in conventional capacitor element 101;

EMBODIMENT OF THE INVENTION Hereinafter, embodiment at the time of applying this invention to an electrolytic capacitor as a winding type electrical storage device is described in detail, referring drawings.

[Structure of electrolytic capacitor]
FIG. 1 is a front view showing the appearance of an electrolytic capacitor 1 according to one embodiment of the present invention, and FIG. 2 is an exploded view showing constituent parts of the electrolytic capacitor 1 according to one embodiment of the present invention.
As shown in FIG. 2 , the electrolytic capacitor 1 of this embodiment includes a capacitor element 10 , a case 21 and a sealing body 22 .

Capacitor element 10 (see FIG. 2) is an element that stores and releases electric charge by electrostatic capacitance, and is housed inside case 21 .
The case 21 is a bottomed cylindrical body made of an aluminum material, and is open at one end in the axial direction and closed at the other end.

The sealing member 22 is an insulating, substantially cylindrical member that seals the opening of the case 21 housing the capacitor element 10, and is made of, for example, rubber or synthetic resin.

[Configuration of Capacitor Element]
Next, capacitor element 10 will be described.
FIG. 3 is an explanatory diagram showing components of the capacitor element 10. As shown in FIG.
As shown in FIG. 3 , capacitor element 10 has anode foil 2 , cathode foil 3 , multiple separators 4 , anode terminal 5 , cathode terminal 6 , and element fixing tape 7 .

The anode foil 2 is a long belt-like electrode foil made of a valve metal such as aluminum, and as will be described later, an oxide film that serves as a dielectric is essentially formed on the surface. The cathode foil 3 is a long belt-like electrode foil made of a valve metal such as aluminum, like the anode foil 2 . The anode foil 2 and the cathode foil 3 are rectangular, and for the convenience of the following description, the width extending in the longitudinal direction of the rectangle will be referred to as the lateral width, and the width extending in the direction perpendicular to the longitudinal direction will be referred to as the longitudinal width. do. Anode foil 2 and cathode foil 3 have the same vertical width, but cathode foil 3 is set longer than anode foil 2 in width. The anode foil 2 has a thickness of 0.05 to 0.11 mm, and the cathode foil 3 has a thickness of about 0.02 to 0.05 mm.

The surface of the anode foil 2 is roughened by etching (etching pits are formed) and an anodized film is formed by anodization (chemical conversion). Similarly to the anode foil 2, the cathode foil 3 is also made of aluminum or the like, and its surface is roughened (etching pits are formed) and a natural oxide film or an anodized film is formed. Incidentally, the surface of the cathode foil 3 may be formed with Ti, TiN, TiC, or the like.

The separator 4 is a rectangular band-shaped electrolytic paper or non-woven fabric, and both surfaces of which hold a driving electrolyte and/or a solid electrolyte. According to this embodiment, two separators 4 are used. These two separators 4 are called separators 4a and 4b, respectively. The separators 4a and 4b have the same vertical width, and the horizontal width of the separator 4b is set longer than that of the separator 4a. The vertical width of the separators 4a and 4b is slightly longer than the vertical width of the anode foil 2 and the cathode foil 3, and the horizontal width of the separators 4a and 4b is set longer than the horizontal width of the cathode foil 3.

Anode terminal 5 is a conductive metal member electrically connected to anode foil 2 . The cathode terminal 6 is a conductive metal member electrically connected to the cathode foil 3 .

The element-fixing tape 7 is based on a long film of polypropylene, polyphenylene sulfide, or the like. It has an adhesive surface. The vertical width of the element fixing tape 7 is preferably 70% or more of the vertical width of the electrode foil and equal to or less than the vertical width of the separator 4, and more preferably equal to or more than the electrode foil and equal to or less than the separator 4.

The wound body 8 is obtained by stacking four sheets each composed of an anode foil 2, a cathode foil 3, and two separators 4a and 4b in the order of the anode foil 2, the separator 4a, the cathode foil 3, and the separator 4b. It is constructed by winding from the starting end to the terminal end of the sheet. At this time, the anode foil 2 is on the inner side in the radial direction and the separator 4a is on the outer side in the radial direction. Further, the anode terminal 5 is arranged at a prescribed portion of the anode foil 2, the cathode terminal 6 is arranged at a prescribed portion of the cathode foil 3, and the anode terminal 5 and the cathode terminal 6 are also wound together with the four sheets. Thus, the wound body 8 is formed into a cylindrical body by winding four sheets, and the anode terminal 5 and the cathode terminal 6 are configured to protrude from one end surface of the cylindrical body.

A capacitor element 10 is formed by attaching an element fixing tape 7 to the wound body 8 so as to encircle the side surface of the cylindrical body. The width of the element fixing tape 7 is set to be longer than the outer periphery of the wound body 8 and the length of the vertical width is set to be approximately equal to the vertical width of the anode foil 2 . Therefore, the element fixing tape 7 can be wound around the wound body 8 one or more times. As a result, the four sheets are kept in a cylindrical shape without being separated from each other.

[Manufacturing method of capacitor element]
Next, a method for manufacturing the electrolytic capacitor 1 will be described with reference to FIG. First, the surfaces of the anode foil 2 and the cathode foil 3 are roughened by etching. Further, the roughened surface of anode foil 2 is subjected to chemical conversion treatment to form an anodized film, and cathode foil 3 is subjected to water-resistant treatment and/or heat treatment to form a natural oxide film (step S1).

Subsequently, the anode foil 2 and the cathode foil 3, on which the anodized film and the natural oxide film are formed, are cut to a specified width according to the size of the case 21 using a cutter blade (step S2). In this embodiment, the specified portion in the width direction is cut in the length direction. For this reason, the anode foil 2 and the cathode foil 3 are formed in a rectangular shape whose width is longer than its height.

Subsequently, the anode terminal 5 and the cathode terminal 6 are connected to the cut anode foil 2 and cathode foil 3, respectively. Then, the anode foil 2 and the cathode foil 3 are overlapped and wound with the separators 4a and 4b interposed therebetween to form a cylindrical wound body 8 (step S3). At this time, since a cutter blade is used for cutting the anode foil 2 and the cathode foil 3 , a warp called a cut burr is formed at the cut portion, ie, the end portion of the anode foil 2 and the cathode foil 3 . In the present embodiment, when the separators 4a and 4b, the anode foil 2, and the cathode foil 3 are superimposed and wound, the warpage of the end portions of the anode foil 2 and the cathode foil 3 is directed outward in the wound body 8. Thus, the surfaces of the anode foil 2 on which the separators 4a are to be superimposed are defined in advance.

Next, the element fixing tape 7 is attached to the wound body 8 to stop the wound body 8, thereby forming the capacitor element 10 (step S4). Specifically, as shown in FIG. 5A, the starting end of the element fixing tape 7 is directly adhered to the terminal end of the anode foil 2 so as to overlap. In this embodiment, the vertical width of the element fixing tape 7 is the same as the vertical width of the anode foil 2 . Then, a press (not shown) is applied to the adhering portion, and the wound body 8 is rotated without moving the press, so that the element fixing tape 7 is wound together with the cathode foil 3 and the separators 4a and 4b. Finally, the end portion of the element fixing tape 7 is adhered to the surface of the element fixing tape 7 . Thereby, the capacitor element 10 is assembled as shown in FIG. 5(b).

Next, after impregnating capacitor element 10 formed in step S4 with an electrolytic solution, capacitor element 10 is inserted into case 21 and the opening of case 21 is sealed with sealing member 22 (step S5). At this time, the lead wires of the anode terminal 5 and the cathode terminal 6 extending from the capacitor element 10 are protruded outside from the case 21 through the through holes formed in the sealing member 22 . After that, the side surface of the opening of case 21 is drawn, and the inside of case 21 is completely airtightly sealed with sealing member 22, whereby electrolytic capacitor 1 is assembled as shown in FIG.

FIG. 6 is a cross-sectional view showing the configuration near the end portion of anode foil 2 in capacitor element 10 . FIG. 7 is a plan view showing a winding mode of the capacitor element 10. FIG. In the capacitor element 10 , the starting end of the element-fixing tape 7 is adhered to the end of the anode foil 2 so that the end of the element-fixing tape 7 overlaps the end of the anode foil 2 and the end of the cathode foil 3 . and the separator 4b intervene. As a result, the thickness is increased by the thickness of the element-fixing tape 7, so even if the cut burr A occurs at the terminal end of the anode foil 2, the tip of the cut-burr A penetrates both the element-fixing tape 7 and the separator 4b and reaches the cathode foil 3. becomes difficult to reach. In particular, according to this embodiment, since the material of the device fixing tape 7 is PPS, polyimide, polystyrene, or the like, the cut burr A does not penetrate through the device fixing tape 7 .

According to the present embodiment configured as described above, since the starting end of the element fixing tape 7 is stuck between the anode foil 2 and the cathode foil 3, the terminal end of the anode foil 2 is stuck. Even if a cut burr is generated, it becomes difficult for the tip of the cut burr to reach the cathode foil 3 . This prevents the anode foil 2 and the cathode foil 3 from coming into direct contact with each other due to cut burrs generated at the end portion of the anode foil 2, thereby preventing the occurrence of a short circuit. Further, according to the present embodiment, since the material of the element-fixing tape 7 is PPS, polyimide, polystyrene, or the like, cut burrs do not penetrate the element-fixing tape 7. It is possible to reliably prevent the occurrence of a short-circuit state due to cut burrs.

As mentioned above, although embodiment of this invention was described, embodiment of this invention is not restricted to embodiment mentioned above. For example, in the above-described embodiment, when the anode foil 2 reaches the terminal end by winding the four sheets, the starting end of the element fixing tape 7 is adhered to the terminal end. The starting end of the element fixing tape 7 may be attached to the terminal end of the anode foil 2 in advance before winding the .

Further, in the above-described embodiment, in the outer peripheral portion of the capacitor element 10, the terminal portion of the anode foil 2 is arranged radially inward and the terminal portion of the cathode foil 3 is arranged radially outward. The starting end of the element fixing tape 7 is adhered to the terminal end. However, in the case of a capacitor element in which the end portion of the anode foil 2 is arranged radially outward and the end portion of the cathode foil 3 is arranged radially inward in the outer peripheral portion of the capacitor element, the end portion of the cathode foil 3 The starting end of the element fixing tape 7 may be adhered.

In the above-described embodiment, the starting end of the element fixing tape 7 is attached to the terminal end of the anode foil 2 (or cathode foil 3). It may be attached to the separator 4 a interposed between the terminal end of the anode foil 2 and the terminal end of the cathode foil 3 .

Furthermore, the element-stopping tape 7 may be formed by arranging a plurality of element-stopping tapes in the longitudinal direction (axial direction) and adhering them.

Further, in the above-described embodiment, the case where the present invention is applied to an electrolytic capacitor has been described, but it is not limited to this, and the present invention can be applied to an anode through a separator such as an electric double layer capacitor, a primary battery, a secondary battery, etc. The present invention can be applied to all roll-type electric storage devices having an electric storage element in which a wound body formed by winding a foil and a cathode foil is wound with an element-fixing tape.

1 Electrolytic capacitor 2 Anode foil 3 Cathode foil 4, 4a, 4b Separator 5 Anode terminal 6 Cathode terminal 7 Element fixing tape 8 Winding body 10 Capacitor element 21 Case 22 Sealing body

Claims (2)

A wound-type electricity storage device comprising an electricity storage element and a case in which the electricity storage element is housed,
The electric storage element includes a winding body obtained by winding a first electrode foil that is one of an anode and a cathode and a second electrode foil that is the other with a separator interposed therebetween, and a winding body wound around the circumference of the winding body. and has an element-stopping tape that maintains the wound state of the wound body,
A starting end portion of the element fixing tape is positioned between the first electrode foil and the second electrode foil, and is arranged radially inward of the wound body between the first electrode foil and the second electrode foil. 1. A wound electricity storage device, characterized in that the electrode foil is adhered so as to overlap with a radially outer end portion of an electrode foil including the outer end portion . a cutting step of cutting an electrode foil material to form a first electrode foil that is one of an anode and a cathode and a second electrode foil that is the other;
a winding step of overlapping the first electrode foil and the second electrode foil with a separator interposed therebetween and winding them from the starting end to the terminal end to form a wound body;
an element-fixing step of winding an element-fixing tape having an adhesive surface on one side and a non-adhesive surface on the other side around the outer peripheral surface of the wound body. A method for manufacturing a storage battery device,
In the winding step, the first electrode foil is positioned radially inward of the wound body, and the warp of the end portion of the first electrode foil generated in the cutting step faces the outside of the wound body. placed and
In the element-fixing step, the starting end of the element-fixing tape is positioned between the first electrode foil and the second electrode foil, and the radially outer end of the first electrode foil includes the outer end. 1. A method for manufacturing a wound electricity storage device, characterized by stacking and pasting together.

Images