JPH1186877A - Winding method for spiral electrode body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a winding method of a spiral electrode body which is simple and is superior in workability and is satisfactory in winding precision. SOLUTION: A sheet-like positive electrode 1 and a sheet-like negative electrode 2 are superposed via a separator 3, and are wound by a winder 20, and a spiral electrode body is formed. In this case, the sheet-like positive electrode 1 and the negative electrode 2 are wound in advance in a hoop shape by a single cell quantity, and are set in the winder 20. While delivering a set hoop- shaped sheet electrode, it is wound around this by interposing the separator 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for winding a spiral electrode body for use in an electrochemical device such as a cylindrical battery or an electric double layer capacitor having a spiral electrode structure.

[0002]

2. Description of the Related Art FIG. 7 is a schematic view of a winding machine showing a conventional method of winding a spiral electrode body.

[0003] The spiral electrode body is composed of a sheet-like positive electrode 1 and a negative electrode 2 each formed by applying an active material to a current collector made of a metal foil and overlapping them with a microporous membrane separator 3 interposed therebetween. As shown in FIG. 7, in the conventional method, each of the sheet-like electrodes 1 and 2 is flat on the tray 22 for the positive electrode and the tray 23 for the negative electrode, as shown in FIG. And winding has been performed by a mandrel 21 attached to the center of the apparatus. This example shows a mode in which winding is performed while cutting the positive electrode 1 and the negative electrode 2 into a length of one cell, and the tips of the positive electrode 1 and the negative electrode 2 are formed on the mandrel 21 together with the separator 3. After the mandrel 21 is inserted into the split groove, the mandrel 21 is rotated, so that the positive electrode 1 and the negative electrode 2 are spirally wound with the separator 3 as a core.

In FIG. 1, G placed on the trays 22 and 23 via the positive electrode 1 and the negative electrode 2 and G2 attached to the leading end of the unrolled separator 3 correspond to the sheet electrodes 1 and 2 and the separator 3 respectively. It is a weight for giving a suitable winding tension. A positive electrode lead plate 4 is welded to the front end of the positive electrode 1 and a negative electrode lead plate 5 is welded to the rear end of the negative electrode 3.

FIG. 5 is an external view of the manufactured electrode body 11. The electrode body 11 has a cylindrical shape having a spiral structure, and a positive electrode lead plate 4 is attached to a core and a negative electrode lead plate 5 is attached to a side edge. This figure is a configuration example in which one electrode body 11 is provided with one positive electrode lead plate 4 and one negative electrode lead plate 5, but the number of these lead plates 4 and 5 affects the internal resistance of the cell. Some cells that require extremely low resistance or large-sized cells have a configuration in which a plurality of lead plates are attached to a single spiral electrode body in order to increase current collection efficiency.

[0006]

Normally, an electrochemical element (for example, a battery or an electric double layer capacitor) using a spiral electrode body has a positive electrode 1 and a negative electrode 2 formed by winding a band-like sheet electrode. Is characterized in that the opposing area is increased to reduce the internal resistance as much as possible.

Meanwhile, in cells of the same size, the sheet electrode tends to be thinner and longer in a limited volume in order to reduce the internal resistance. Particularly, in a large cell, etc., a sufficient electrode area is required. For example, 10
m long sheet electrodes may be required.

However, the conventional winding method in which the sheet electrode is supplied to the winding machine 20 in a flat state requires the long trays 22 and 23 corresponding to the sheet length. It became expensive. In addition, the longer the sheet electrode becomes, the more difficult it is to set the electrode, and the more easily the electrode is likely to be displaced or wrinkled during winding. There was a problem in terms.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for winding a spiral electrode body which solves the problems of the conventional method described above, is simple, has excellent workability, and has good winding accuracy.

[0010]

That is, according to the first aspect of the present invention, a sheet-shaped positive electrode (1) and a sheet-shaped negative electrode (2) are overlapped with a separator (3) interposed therebetween and wound. In the method for winding a spirally wound electrode body wound by a winding machine (20), the positive electrode (1) and the negative electrode (2) are wound in a hoop shape by one cell in advance in the winding machine (20). And the wound hoop-shaped positive electrode (1) and negative electrode (2) are wound together with the separator (3) while being fed out.

According to the present invention, the hoop-shaped positive electrode (1) and negative electrode (2) are set in the winding machine (20) in a state of being stored in a cassette (25), respectively. It is characterized by the following.

Further, according to the present invention, a sheet-like positive electrode (1) having a plurality of positive electrode lead plates (4) is provided.
And a sheet-shaped negative electrode (2) provided with a plurality of negative electrode lead plates (5), with a separator (3) interposed therebetween, and wound by a winding machine (20). , The positive electrode (1) and the negative electrode (2) are cut and divided in advance so as to have at least one or more positive electrode lead plates (4) and negative electrode lead plates (5), respectively. ), And the supplied positive electrode (1) and negative electrode (2) are grouped one by one and wound together with the separator (3).

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a process for manufacturing a spiral electrode body according to the present invention will be described. To simplify the description, the same reference numerals are used in the following description for portions common to the related art.

First, a predetermined amount of an active material (for example, activated carbon is used in the case of an electric double layer capacitor), a conductive material such as acetylene black, and PVDF (polyvinylidene fluoride) as a binder are mixed in predetermined amounts, and NMP (N -Methylpyrrolidone) solvent is added, mixed and kneaded to form a slurry.

Next, for example, the slurry mixture is coated on both surfaces of an aluminum foil serving as a positive electrode current collector and a negative electrode current collector by a doctor blade method or the like, and dried and rolled (rolled). Each is cut into a predetermined width to form a band-shaped sheet electrode, that is, a positive electrode 1 and a negative electrode 2.

In the first embodiment of the present invention, after the sheet electrode is formed, the positive electrode 1 and the negative electrode 2 are cut to the length of one cell in the next step, and each is wound into a hoop shape.

Next, these hoop-shaped positive electrode 1 and negative electrode 2
Are stored in the cassette 25 (they may be used in a hoop state without being stored in the cassette 25) and dried under reduced pressure.
For example, as shown in FIG. 2, the storage cassette 25 includes a main body and a lid, and is a cylindrical body having a support shaft 27 inside the main body. The core is inserted into the support shaft 27, and the end of the electrode is slightly pulled out from the outlet 26 and covered.

Further, the uncoated portion of the mixture (in the example of FIG. 1,
The welding of the lead plate to the sheet end) may be performed when the hoop is formed or when the cassette is housed, or may be performed when the hoop-shaped electrode is fed in a winding step described later.

FIG. 1 is a schematic view of a winding machine showing a first embodiment of the present invention.

In the figure, 1 is a sheet-like positive electrode, and 2 is a negative electrode. Each is set at a predetermined position of the winding machine 20 in a state of being wound up in a hoop shape. When the hoop-shaped electrodes 1 and 2 are stored in the cassette 25, the cassette 25 and the hoop-shaped electrodes 1 and 2 are set at predetermined positions of the winding machine 20.
Reference numeral 3 denotes a separator wound in a hoop shape, and a weight G2 for winding tension is attached to the tip of the separator. At the time of winding, the positive electrode 1 and the negative electrode 2 are fed out onto the tray 22 and the tray 23, respectively, and supplied to the mandrel 21, and after inserting the end of each sheet into the split groove together with the separator 3, the mandrel 21 is rotated. Thereby, the positive electrode 1 and the negative electrode 2 are spirally wound around the separator 3 through the separator 3 to form a spiral electrode body 11 as shown in FIG. G1 and G1 installed on the positive electrode tray 22 and the negative electrode tray 23 are the positive electrode 1
And a tension roll for obtaining a winding tension of the negative electrode 2.

As described above, in the first embodiment, the configuration is such that the coated and rolled sheet-shaped electrode for one cell is previously formed into a hoop and is supplied to the winding machine 20 so that the tray 2
2, 23 can be shortened and the winding machine itself can be made compact, so that workability is improved. Also, by making the sheet electrodes hoop-shaped, strength can be given in the width direction of each sheet electrode as compared with the conventional method of setting the electrodes in a flat state, so that positioning of the electrodes in the width direction becomes easier. , Winding accuracy can be improved.

The hoop-shaped positive electrode 1 and negative electrode 2
Are stored in the respective cassettes 25, the handling properties are further improved, and the setting to the winding machine 20 can be easily performed.

Next, another embodiment of the manufacturing process of the spiral electrode body will be described.

As in the first embodiment, first, activated carbon as an active material, a conductive material such as acetylene black, and PVDF (polyvinylidene fluoride) as a binder are mixed in predetermined amounts, respectively, and then mixed with NMP (N-methylpyrrolidone). A solvent is added, mixed and kneaded to form a slurry.

Next, uncoated portions A are formed at predetermined intervals on both surfaces of an aluminum foil serving as a positive electrode current collector and a negative electrode current collector by a doctor blade method, as shown in FIG. Then, after intermittent application, drying and rolling (roll rolling), each is cut into a predetermined width to form a band-like sheet electrode (positive electrode 1 and negative electrode 2).

In the second embodiment of the present invention, in the next step, the above-mentioned sheet electrodes 1 and 2 are not coated with the mixture A as shown in FIG.
And divide it into a plurality of electrodes. Next, a lead plate (positive electrode lead plate 4 and negative electrode lead plate 5) is welded to the unpainted portion A of each electrode, that is, the end of each electrode, and dried under reduced pressure.

Next, as shown in FIG.
To the tray 22 for the positive electrode of the winding machine 20 and the negative electrode 2 to the tray 23 for the negative electrode in turn. These are grouped one by one, and are wrapped around the mandrel 21 as the core via the separator 3. .

When the spiral electrode body is formed, the plurality of lead plates are finally connected to the positive lead plate 4 and the negative lead plate 5 respectively.
Terminal (+ pole) and outer can (-pole) which are bundled separately
, The divided electrodes are again conducted through the respective lead plates 4 and 5, and function as a single electrode.

As described above, in the second embodiment, the intermittently coated and rolled sheet electrode for one cell is welded in advance to weld a plurality of lead plates, and the sheet electrode is cut and divided in advance at the uncoated portion. After the lead plate is welded to the electrode, the divided electrodes are sequentially supplied to the winding machine 20 so that the winding machine 2
0 can be shortened (that is, the length of the trays 22 and 23 is only required to be the length of the divided unit electrodes), and the winding device is made compact and workability is improved.

Further, by dividing the electrode into a plurality of parts and shortening the length per unit electrode, it is possible to prevent an increase in the winding deviation which tends to occur in the conventional method of continuous winding in a flat state, and furthermore, Since displacement can be corrected when the next electrode is supplied, accurate winding can be performed.

FIG. 6 is a sectional view showing the internal structure of a cylindrical non-aqueous secondary battery as an electrochemical element using a spiral electrode body to which the present invention is applied. In the figure, 1 is a positive electrode formed by applying a positive electrode mixture to a positive electrode current collector 6, 2 is a negative electrode obtained by applying a negative electrode mixture to a negative electrode current collector 7, 3 is the positive electrode 1 and the negative electrode 2.
These are stacked and wound by the above-described method, and are housed in a cylindrical metal case 8 as a spiral electrode body 11.

A positive electrode cap 10 is attached to the head of the metal case 8 via a sealing gasket 9.
The positive electrode cap 10 is connected to the positive electrode 1 via the positive electrode lead plate 4.
The bottom of the metal case 8 is electrically connected to the negative electrode 2 via the negative electrode lead plate 5.

[0033]

As described above, according to the first aspect of the present invention, a sheet-like electrode cut to the length of one cell is formed into a hoop before being supplied to a winding machine. In this case, the width of the winding machine can be shortened, and the apparatus itself is made compact, so that the winding operation is simplified. Further, by setting the sheet electrode in the hoop shape in the winding machine in this manner, the strength in the sheet width direction is generated on the electrode and the positioning in the width direction is facilitated, so that the winding accuracy is improved.

According to the present invention described in claim 2,
Since the hoop-shaped sheet electrode is housed in the cassette, the handleability is further improved, and the setting to the winding machine becomes easy.

Further, according to the present invention, the sheet electrode for one cell is divided in advance so as to have at least one or more lead plates and supplied to the winding machine. In addition, the width of the winding machine can be shortened, and the winding device itself is made compact, so that the winding operation is simplified. In addition, since the electrode is divided into a plurality in this manner, the length per unit electrode is shortened, so that the winding deviation gradually decreases as in the conventional method in which the sheet electrode for one cell is continuously wound in a flat state. It will not expand. In addition, since the winding deviation can be corrected each time the next divided electrode is supplied, accurate winding can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic view of a winding machine showing a method for winding a spiral electrode body according to the present invention.

FIG. 2 is a schematic external view showing a mode in which hoop-shaped electrodes are housed in a cassette.

FIG. 3 is a view showing a manner of dividing a sheet-like electrode, and attaching a lead plate to the divided electrode.

FIG. 4 is a schematic view of a winding machine showing another winding method of the spiral electrode body according to the present invention, which is different from FIG.

FIG. 5 is an external view of a spiral electrode body.

FIG. 6 is a sectional view showing the internal structure of a cylindrical non-aqueous secondary battery to which the present invention is applied.

FIG. 7 is a schematic view of a winding machine showing a conventional winding method of a spiral electrode body.

[Explanation of symbols]

 Reference Signs List 1 positive electrode 2 negative electrode 3 separator 4 positive electrode lead plate 5 negative electrode lead plate 20 winding machine

Claims (3)

[Claims] 1. A spirally wound electrode body in which a sheet-like positive electrode (1) and a sheet-like negative electrode (2) are overlapped with a separator (3) interposed therebetween and wound by a winding machine (20). In the method, the positive electrode (1) and the negative electrode (2) are set in the winding machine (20) in a state of being wound in a hoop shape by one cell in advance,
A method for winding a spiral electrode body, comprising winding a hoop-shaped positive electrode (1) and negative electrode (2) set together and winding the same together with the separator (3). 2. The winding machine (20) according to claim 1, wherein the hoop-shaped positive electrode (1) and negative electrode (2) are set in the winding machine (20) in a state of being housed in a cassette (25), respectively. A method for winding a spiral electrode body. 3. A sheet-like positive electrode (1) having a plurality of positive electrode lead plates (4) and a sheet-like negative electrode (2) having a plurality of negative electrode lead plates (5) with a separator (3) interposed. In the method of winding a spiral electrode body, wherein the positive electrode (1) and the negative electrode (2) are each at least one or more positive electrode lead plates (4) and negative electrodes, The lead (5) is cut and divided in advance so as to have a lead plate (5), and is sequentially supplied to the winding machine (20). The supplied positive electrode (1) and negative electrode (2)
Are wound one by one together with the separator (3).