JPH1031998A - Method for taking up metal film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a method for supplying a metal film without risk of interruption by preventing severance of film to be taken up. SOLUTION: A film-form original metal of a copper foil 21 is to be threaded through a coating device to apply a negative electrode active material to the metal of copper foil 21 to be made a negative electrode of a Li battery or the like, and for threading the copper foil 21 through the running system 111 consisting of an unroller 112, takeup roll (not illustrated), and a plurality of guide rolls 113 for guidance of the running operation, the tail of the first polyester film base 121 having a smaller thickness is connected in butting to the head of the second polyester film base 131 having a larger thickness, wherein first the front and rear surfaces of the butted part are adhered by a polyester adhesive tape 127 in the direction across the width of film, and then the front surface of the butted part is adhered in a plurality of positions (three in the illustration) by a polyester adhesive tape 128 stretching in the longitudinal direction of the copper foil 21, followed by the start of taking up the metal film.

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 metal film, and more particularly to a method for winding an original metal foil film in a secondary battery electrode manufacturing process.

[0002]

2. Description of the Related Art A battery is roughly classified into a primary battery and a secondary battery. When the primary battery is discharged once, the life of the battery is terminated. However, the secondary battery is discharged many times by being charged again after being discharged. Can be repeated. The secondary battery includes a lead battery, a nickel cadmium battery, a nickel metal hydride battery, a lithium ion battery, and the like. Among these, lithium ion batteries have a high capacity density per volume, and the voltage is about three times higher than that of nickel cadmium batteries.
Since lithium in the battery exists in an ionic state and has extremely high safety, it is used in many fields as a power source for portable electronic devices and the like. is there.

FIG. 4 is a partially cutaway perspective view of a lithium ion battery, showing the internal structure of the cell 1. Inside the cell 1, a film-shaped positive electrode 10 and a negative electrode 20 having a predetermined width are wound in close contact with separators 30, 30 sandwiched therebetween.

FIG. 5 shows a cross section of the positive electrode 10. The positive electrode 10 is, for example, one in which lithium composite oxides 12 and 12 are applied to both surfaces of an aluminum foil 11 having a thickness of several tens of μm.
FIG. 6 shows a cross section of the negative electrode 20. The negative electrode 20 is formed, for example, on both surfaces of a current collector 21 made of a copper foil, hard carbon as the negative electrode active material, oxalic acid as an additive, and N as a binder.
Negative paints 22 and 22 dispersed and kneaded with MP (N-methyl-2-pyrrolidine) and PVDF are applied.

The process of applying the negative electrode paints 22, 22 to the copper foil 21 to manufacture a negative electrode is performed in the coater 110 of the electrode manufacturing apparatus 100 shown in FIG. Electrode manufacturing apparatus 100 shown in FIG.
The raw metal foil is unwound in the coater 110, and the steps of applying the electrode material to the raw metal foil, drying (recovering the solvent), and cooling are sequentially performed and then rewinded.
Also in the press 120, the metal foil raw material coated with the electrode material is unwound, pressed, and wound again. Next, the metal foil raw material coated with the electrode material is cut into a skid by the slitter 130 so as to form a film having an electrode width as a product.

[0006] In the coater 110, a film-shaped metal foil roll wound in a wide roll shape is sent out from an unwinding roll (not shown), and is wound up through a coating process, a drying process, and a cooling process. It is wound by a roll (not shown) to obtain a wound metal foil (not shown).

The winding speed is generally 15 to 100.
m / min and tension is approximately 30 kg / 600 mm
The width is controlled. The wound metal foil on which the electrode material has been applied is then transferred to a cutting step, where the cell 1 serving as a battery is formed.
It is cut to a predetermined width dimension (FIG. 4).

The running system 111 of the coater 110 includes FIG.
The unwinding roll 112 for running the copper foil 21 and the plurality of guide rolls 11 for guiding the running as shown in FIG.
A traveling system 111 including 3, 113,...

Conventionally, as a method of passing the copper foil 21 through the running system 111 of the coater 110, first, a thin polyester film base 121 is passed through the running system 111 to form a winding lead, and the unwinding of the film-shaped metal foil raw material is performed. Roll 1
In 12, the method of connecting the polyester film base 121 and the copper foil 21 was used.

That is, in the conventional method, FIGS.
As shown in FIG. 10 (side view) and FIG. 10 (side view), the polyester film base 121 and the copper foil 21 are overlapped at both ends thereof as a method of connecting the polyester film base 121 and the copper foil 21. Adhesion was performed in the width direction with a tape 125, and then several places (three places in the figure) were connected in the longitudinal direction with polyester adhesive tapes 126, 126, 126.

The purpose of this is to prevent the copper foil 21 from being cut. According to this method, the wrinkles of the polyester film base 121 can be removed well, but the copper foil 21
When passing through, the copper foil 21 at the take-up lead portion cannot be used for the product and causes loss, but if the take-up lead is passed through the polyester film base 121 first, the copper foil 21 is removed except for the connection portion. Almost all can be used for the product, and the work of passing the winding lead through the traveling system 111 is much easier with the thin polyester film base 121.

[0012]

However, first, the thin polyester film base 121 is moved to the running system 11.
According to the method of connecting the polyester film base 121 and the copper foil 21 in the unwinding roll 112 through the first roll 1, the wrinkles of the polyester film base 121 can be removed well, but the copper foil 21 passes through the coating process of the coater 110 and When running to the drying step, the copper foil 21 was easily wrinkled, and the copper foil 21 was often cut in the pinch roll after the drying step. Copper foil of film metal foil 2
In many cases, two thicknesses of 10 μm and 15 μm were used, and among them, a thickness of 10 μm was often cut in the drying step.

[0013] An object of the present invention is to provide a method of supplying a continuous film of a metal film such as a copper foil, which is prevented from being cut in a pinch roll after a drying step.

[0014]

The above object of the present invention is attained by the following constitution. As described above, the present invention provides a metal film to be wound such as a copper foil at a joint between a plastic film base such as polyester having a relatively small thickness and a metal film to be wound such as a copper foil. It is often cut from the wrinkles that occur, and the wrinkle removal method is focused on removing wrinkles that occur at the connection seam between the plastic film base such as thin polyester and the film to be wound such as copper foil. As a result of the examination, a method of inserting a second relatively thick plastic film base such as polyester between a relatively thin plastic film base such as polyester and a film to be wound such as copper foil As a result, the above problem could be solved.

That is, the present invention has the following configuration. In order to wind a metal film to be wound around a winding roll, a first relatively thin plastic film is formed as a winding lead portion, and the first relatively thin plastic film is formed. The front end of the second relatively thick plastic film is spliced and connected to the rear end of the second thick plastic film, and the roll is wound around the rear end of the second relatively thick plastic film. The front end of the metal film to be wound is joined and connected, and the joint connection portion of these two types of plastic films is used as the unwinding portion of the metal film to be wound. This is a method of winding a metal film to start winding.

In the above-mentioned method for winding a metal film of the present invention, the thickness of the first relatively thin plastic film is approximately 20 μm, and the thickness of the second relatively thick plastic film is The length can be approximately 75 μm.

Also, the width of the joint portion between the rear end of the first relatively thin plastic film and the front end of the second relatively thick plastic film is 30 cm or more. The object of the present invention can be sufficiently achieved.

In the method for winding a metal film of the present invention, the metal film is a film-shaped metal foil raw material used for, for example, the production of a battery electrode.

In accordance with the present invention, a first relatively thin polyester film base such as polyester provides a lead for winding and a second relatively thick polyester film base provides copper. Since tension is uniformly applied in the width direction to the metal film to be wound, such as a foil, even if wrinkles or partial elongation occurs in the first plastic film base such as polyester having a relatively small thickness, the second tension is applied. The relatively thick plastic film base absorbs wrinkles and stretches and applies even tension in the width direction of the copper foil, so that the metal film to be wound, such as copper foil, is torn or cut. It acts to prevent it.

[0020]

Embodiments of the present invention will be described below. Example 1 An example of the present invention is shown in FIGS. 1 and 2 (a plan view of a joint portion of a film) and FIG. 3 (a side view of a joint portion of a film).
That is, in order to prevent the film-shaped metal raw material of the copper foil 21 from being torn or cut, the width is 640 mm and the thickness is 20 μm.
A first relatively thin polyester film base 121 as a lead for winding, and then a width 64
A second relatively thick polyester film base 131 having a thickness of 0 mm was connected, followed by a raw metal foil foil of a copper foil 21 having a width of 640 mm and a thickness of 15 μm or 10 μm.

As shown in FIG. 1, according to the present embodiment, a method of supplying a raw material of a film-like metal foil in an electrode manufacturing process of a secondary battery such as a lithium battery, that is, This is a method of passing a film-shaped metal foil of copper foil 21 through a coater 110 for applying a negative electrode active material to the raw material. The unwinding roll 112, a take-up roll (not shown), and a plurality of guides for traveling. The traveling system 111 including the guide rolls 113, 113,.
First, a relatively thin polyester film base 121 is passed through a traveling system to form a winding lead, and the unwinding roll 112 of the film-shaped metal foil raw material is passed through first.
In the polyester film base 121 and the copper foil 21
Instead of the conventional method of connecting the above, a second relatively thick polyester film base 131 is inserted between the thin polyester film base 121 and the copper foil 21.

The rear end of the first relatively thin polyester film base 121 and the next front end of the second relatively thick polyester film base 131 are butt-connected. The front and back surfaces of the butted portion are adhered in the width direction of the film with a polyester adhesive tape 127, and then the surface of the butted portion is stretched in the longitudinal direction of the copper foil 21 with polyester adhesive tapes 128 and 12 respectively.
At 8 and so on, several places (three places in the figure) were adhered.

The length of the second relatively thick polyester film base 131 was set to 300 mm or more, and then, the film-shaped metal foil of the copper foil 21 was overlapped and connected.

After the front end of the film-shaped metal foil raw material of the copper foil 21 is overlaid on the rear end of the second relatively thick polyester film base 131, first, the front and back surfaces of the overlapped portion are connected. Polyester adhesive tapes 136, 136,... Are adhered in the width direction of the film with a polyester adhesive tape 135, and then the surface of the overlapped portion extends in the longitudinal direction of the copper foil 21.
・ A few places (three places in the figure) adhered.

Table 1 shows the test results of the second embodiment in which the thickness of the film base 131 made of a relatively thick polyester and the thickness of the film-shaped metal foil of the copper foil 21 were respectively changed.

[0026]

[Table 1]

As is apparent from Table 1, the first relatively thin polyester film base 121 is used as a lead for winding, and then the second relatively thick polyester film base 121 is used as a lead. 131, followed by a film-shaped metal substrate of a copper foil 21 having a thickness of 15 μm or 10 μm, and a second relatively thick polyester film base 131 having a thickness of 75 μm If the thickness of the film-shaped metal raw material of the copper foil 21 is 15 μm or 10 μm, no wrinkles are generated, but the second relatively thick polyester film base 131 is formed. When the thickness is 50 μm, the thickness of the film-shaped metal raw material of the copper foil 21 is small.
It is recognized that wrinkles occur in the copper foil 21 when the thickness is 0 μm, and when the thickness of the second thick polyester film base 131 is set to 30 μm, the thickness of the film-shaped metal raw material of the copper foil 21 becomes 15 μm or 10 μm. In each case, the occurrence of wrinkles was always observed, so it was judged that the optimal thickness of the second thick polyester film base 131 was 75 μm.

According to the present embodiment, a method for supplying a film metal foil raw material in an electrode manufacturing process of a secondary battery such as a lithium battery, that is, a method for supplying a negative electrode active material to a film metal raw material of a copper foil 21 serving as a negative electrode. Is a method of passing a film-shaped metal foil raw material of the copper foil 21 through a coater 110 for applying an unwinding roll 112, a winding roll (not shown), and a plurality of guide rolls 113, 11 for guiding traveling.
In order to pass the copper foil 21 through the traveling system 111 composed of 3,..., First, a relatively thin polyester film base 121 is passed through the traveling system to form a winding lead. The first relatively thick polyester film base 131 is inserted between the thin polyester film base 121 and the copper foil 21 in the unwinding roll 112 of the first roll, so that the first relatively thin polyester film base 131 is inserted. When the film-shaped metal foil of the copper foil 21 is directly connected to the polyester film base 121, the copper foil 21
However, there was a problem that wrinkles and partial elongation occurred, and the film-shaped metal foil of the copper foil 21 was torn or cut.
Relatively thick polyester film base 1
Since the tension is uniformly applied in the width direction of the film to the film-like metal foil raw material of the copper foil 21 by 31, even if wrinkles or partial elongation occurs in the first relatively thin polyester film base 121. Since the second relatively thick polyester film base 131 absorbs wrinkles and elongation and applies a uniform tension in the width direction of the copper foil 21, the film-shaped metal foil of the copper foil 21 is torn. This prevents the film foil of the copper foil 21 from tearing or cutting, thereby exhibiting an excellent effect of preventing a decrease in efficiency in manufacturing the secondary battery electrode due to the tearing or cutting.

The loss length of the raw material foil of the film-shaped metal foil was 50 m / time before the practice of the present invention, but was reduced to 0 m / time by the practice of the present invention. The recovery time of the raw web was 60 minutes / time, but was reduced to 0 minutes / time by implementing the present invention.

[Brief description of the drawings]

FIG. 1 shows a first thin polyester film base according to an embodiment of the present invention, as a lead for winding, then a second thick polyester film base is connected, followed by a copper foil film metal foil. It is a perspective view near the unwinding part of the electrode manufacturing apparatus which connected the raw material.

FIG. 2 is a plan view showing a main part of a method of connecting a first thin polyester film base, a second thick polyester film base, and a copper foil film-shaped metal foil according to an embodiment of the present invention. It is.

FIG. 3 is a side view showing a main part of a method for connecting a first thin polyester film base, a second thick polyester film base and a copper foil film-shaped metal foil according to an embodiment of the present invention. It is.

FIG. 4 is a partially cutaway perspective view showing the internal structure of a cell of a lithium ion battery.

FIG. 5 is a drawing showing a cross section of a positive electrode of a lithium ion battery, in which the lithium composite oxide is applied to both surfaces of an aluminum foil.

FIG. 6 is a drawing showing a cross section of a negative electrode of a lithium ion battery. The negative electrode is obtained by applying a negative electrode paint in which a negative electrode active material, an additive, and a binder are dispersed and kneaded on both surfaces of a copper foil current collector.

FIG. 7 is an overall view of an electrode manufacturing apparatus for manufacturing a negative electrode by applying a negative electrode paint to a copper foil.

FIG. 8 is a perspective view showing a connection portion between a polyester film base and a copper foil in a conventional copper foil traveling system.

FIG. 9 is a plan view showing a main part of a conventional method for connecting a polyester film base and a copper foil.

FIG. 10 is a side view showing a main part of a conventional method for connecting a polyester film base and a copper foil.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cell of lithium ion battery 10 ... Positive electrode 11 ... Aluminum foil 12 ...
Lithium composite oxide, 20 ... negative electrode,
21: copper foil current collector, 22: negative electrode paint,
31 ... separator, 100 ... electrode manufacturing equipment, 110 ... coater, 11
DESCRIPTION OF SYMBOLS 1 ... Running system, 112 ... Unwinding roll, 113 ... Guide roll which guides running, 12
DESCRIPTION OF SYMBOLS 1 ... Thin polyester film base, 125 ... Width-adhesive polyester adhesive tape, 126 ... Longitudinal adhesive polyester adhesive tape, 127 ... Width-directional adhesive polyester adhesive tape, 128 ... Longitudinal adhesive polyester adhesive tape, 131 ... Thick polyester film base

Claims (4)

[Claims] A first relatively thin plastic film is formed as a winding lead for winding a metal film to be wound around a winding roll, and the first relatively thin plastic film is formed. The front end of the second relatively thick plastic film is spliced and connected to the rear end of the thick plastic film, and the rear end of the second relatively thick plastic film is connected to the rear end of the second relatively thick plastic film. The front ends of the metal film to be wound wound in a roll are joined and connected, and the joint portion of these two types of plastic films is wound as the unwinding portion of the metal film to be wound. A method for winding a metal film, comprising starting winding of a target metal film. 2. The thickness of the first relatively thin plastic film is approximately 20 μm, and the thickness of the second relatively thick plastic film is approximately 75 μm.
The method for winding a metal film according to claim 1, wherein: 3. The width of a seam between the rear end of the first relatively thin plastic film and the front end of the second relatively thick plastic film is 3 mm.
3. The method for winding a metal film according to claim 1, wherein the length is not less than 0 cm. 4. The method for winding a metal film according to claim 1, wherein the metal film is a film-shaped metal foil raw material used for manufacturing a battery electrode.