JP7235234B2 - Punching device for metal foil and method for punching metal foil - Google Patents

Description

The present invention relates to a punching device for metal foils such as copper foil, aluminum foil and stainless steel foil, and a method for punching metal foils.

As current collectors for power generation elements that use non-aqueous electrolytes such as lithium ion batteries and lithium ion capacitors, copper foils (or copper alloy foils) generally having a thickness of about several μm to 100 μm are used. foil), aluminum foil (or aluminum alloy foil, hereinafter simply referred to as aluminum foil), and thin and elongated metal foils such as stainless steel foil are used.

For example, a negative electrode plate is produced by applying a negative electrode active material to the surface of a copper foil, and a positive electrode plate is produced by applying a positive electrode active material to the surface of an aluminum foil. A non-aqueous secondary battery such as a lithium ion battery is manufactured by injecting a non-aqueous electrolytic solution into the non-aqueous electrolytic solution after it is wrapped or wound and housed in a package.

By punching a large number of holes having a diameter of several tens of micrometers to several millimeters in these metal foils, the adhesiveness between the negative electrode active material and the positive electrode active material and the metal foil is improved, making it difficult for peeling and detachment to occur. As a result, it is possible to provide a long-life lithium-ion battery or the like that is excellent in high-rate discharge characteristics.

Patent Document 1 discloses a technique of chemically perforating a large number of holes in these copper foils and aluminum foils by etching. Using this technique, it is possible to provide a metal foil having approximately circular holes with a diameter of about 0.1 mm to 3 mm.

Also, a metal foil such as a copper foil or an aluminum foil is placed on the upper surface of an annular mold having a large number of punched holes, and both surfaces thereof are sandwiched between a pair of elastic bodies. Patent Document 2 discloses a technique of mechanically punching holes by pressurizing the elastic portion from the outside with a pair of flat rolls and pressing the metal foil against the upper surface of the mold. Using this technique, it is possible to provide metal foils with holes as small as 3 mm in diameter.

In addition, an elastic belt is placed on a flat roll, a metal foil such as copper foil or aluminum foil is placed thereon, and pressure is applied from above the metal foil using an embossing roll having a large number of protrusions. , Patent Document 3 discloses a technique for mechanically drilling a hole using this convex portion. Using this technique, it is possible to provide a metal foil having pores with diameters on the order of several tens of μm to 500 μm.

In addition, by pressing the aluminum alloy foil sandwiched between an embossing roll having a large number of convex portions and a roll having concave portions, a large number of embossing rolls having a diameter of about 200 μm (0.2 mm) were mechanically formed. Patent Document 4 also discloses a technique for providing a thin plate having holes. By using a metal foil with holes having a diameter of about 200 μm, the energy of noise such as engine noise can be effectively converted into heat. , simply referred to as soundproof structural materials.).

In addition, the applicant of the present application has proposed a technique of forming holes by sandwiching a laminate of metal foil and paper between a perforating roll and a plurality of pressure rolls and applying pressure to the laminate. It is disclosed in Patent Document 5. Using this technique, it is possible to provide a metal foil having a large number of holes with diameters on the order of several tens of μm to 100 μm.

JP-A-11-67217 JP-A-2001-9793 JP-A-2002-216775 Japanese Patent Application Laid-Open No. 2006-116671 JP 2015-57301 A

However, the technique described in Patent Document 1, which chemically perforates a large number of holes in a metal foil by etching as described above, has the problem of high manufacturing costs and the environmental protection problem of cumbersome disposal of waste liquid.

The technique described in Patent Literature 2 requires a large-scale ring-shaped mold, which raises the problem of increased facility costs. In addition, it is expected that it will be difficult to completely collect the piercing debris that has been pierced, and that it will be technically difficult to pierce holes having a diameter of about several hundred μm in terms of mold strength.

Using the technique described in Patent Document 3, it is possible to provide a metal foil having a large number of holes with a diameter of about several tens of μm to 500 μm. However, there is a problem that it is difficult to completely collect the drilling debris generated by drilling. That is, if part of the punching dust adheres to the metal foil after punching, the punching dust part breaks through the separator, causing a short circuit in a non-aqueous secondary battery such as a lithium ion battery. .

The technique described in Patent Literature 4 is a technique of simply forming a hole by crimping, and burrs remain in the hole portion as they are at the time of punching. Therefore, as with the technique described in Patent Document 3, there is a problem that the burrs break through the separator and cause a short circuit in a non-aqueous secondary battery such as a lithium ion battery.

In the technique described in Patent Document 5, the drilled hole is limited to a polygonal shape such as a rhombus. As a result, the holes themselves have edges (corners), which causes problems such as easy tearing and poor tensile strength. In addition, when a thin metal foil having a thickness of several μm to 100 μm is introduced (rolled) into a punching device, manufacturing defects such as wrinkling and twisting have been observed.

The present invention provides a punching device and a metal foil punching method that can make manufacturing equipment compact and inexpensive, reduce defects during manufacturing, and can also manufacture substantially circular holes in addition to polygonal shapes such as substantially rhombic holes. intended to provide.

An object of the present invention is to solve the problems described above.
The invention described in claim 1 is
A metal foil punching device for forming a large number of holes in a metal foil by sandwiching a laminate of a metal foil and paper between a punching roll and a plurality of pressure rolls, applying pressure, and punching the metal foil. hand,
The surface of the perforating roll has a large number of protrusions,
The plurality of pressure rolls are present so as to surround the perforation roll,
At least one pair of the pressure rolls has a large diameter portion and a small diameter portion,
The large-diameter portion of one pressure roll is formed to correspond to the small-diameter portion of the other pressure roll,
The small diameter portion of one pressure roll is formed to correspond to the large diameter portion of the other pressure roll,
The metal foil is
contacting the paper and the convex portion of the perforating roll;
A large number of holes are formed by receiving pressure from the plurality of pressure rolls via the paper and the upper surface of the convex portion, and
Said paper
contacting the pressure roll and the metal foil,
It is characterized in that the punching debris generated by the punching is fixed.

By using the first aspect of the invention, it is possible to use a compact and inexpensive manufacturing facility, and to obtain a metal foil with almost no visible burrs during piercing. In addition, since the paper can be used to fix the drilling debris (copper foil, etc.) generated during drilling to the surface of the paper, it is preferable from the viewpoint of resource conservation and work environment.
The invention according to claim 2 is the invention according to claim 1,
The convex portion is
It has the shape of a truncated quadrangular pyramid, and its top surface is characterized by a substantially rhombic shape.
By using the second aspect of the invention, it is possible to manufacture a metal foil that has substantially rhomboidal fine holes and has almost no visible burrs during perforation.
The invention according to claim 3 is the invention according to claim 1,
The convex portion is
It has a substantially cylindrical shape, and its upper surface is characterized by a substantially circular shape.
By using the invention according to claim 3, it is possible to manufacture a metal foil which has substantially circular minute holes and which has almost no visible burrs at the time of punching.
The invention according to claim 4 is the invention according to claim 1,
The large diameter portion is wider than the small diameter portion,
The large-diameter portion of the one pressure roll and the large-diameter portion of the other pressure roll have overlapping portions.
By using the invention according to claim 4, it is possible to prevent the occurrence of insufficiently perforated portions of the metal foil (so-called uneven perforation).
The invention according to claim 5 is the invention according to claim 1,
A small-diameter portion of the pressure roll on the entrance side of the metal foil is coated with an elastic material.
By using the invention according to claim 5, when the metal foil is introduced into the punching device (when it is rolled up), it is possible to prevent manufacturing defects such as wrinkles and twisting that make rolling in difficult. can.

The invention according to claim 6,
A method for perforating a metal foil, wherein a laminate obtained by laminating a metal foil and paper is sandwiched between a perforation roll and a plurality of pressure rolls, pressed, and perforated to form a large number of holes in the metal foil. hand,
The surface of the perforating roll has a large number of protrusions,
The plurality of pressure rolls are present so as to surround the perforation roll,
At least one pair of the pressure rolls has a large diameter portion and a small diameter portion,
The large-diameter portion of one pressure roll is formed to correspond to the small-diameter portion of the other pressure roll,
The small diameter portion of one pressure roll is formed to correspond to the large diameter portion of the other pressure roll,
The metal foil is
contacting the paper and the convex portion of the perforating roll;
A large number of holes are formed by receiving pressure from the plurality of pressure rolls via the paper and the upper surface of the convex portion, and
Said paper
contacting the pressure roll and the metal foil,
The method of punching a metal foil is characterized in that the punching debris generated by the punching is fixed.

According to the sixth aspect of the present invention, it is possible to use compact and inexpensive manufacturing equipment, and to provide a metal foil manufacturing method in which almost no burrs are observed during perforation. In addition, since the paper can be used to completely collect the drilling scraps (copper foil, etc.) generated during drilling in a state of being fixed on the surface, the production of metal foil is preferable from the viewpoint of resource conservation and work environment. The method.

By using the present invention, the manufacturing equipment can be made compact and inexpensive, and it is possible to manufacture holes having substantially circular shapes in addition to polygonal shapes such as substantially rhombic shapes. In addition, it is possible to provide a metal foil punching device and a metal foil punching method in which defects are less likely to occur during manufacturing. In particular, by forming a substantially circular hole, it is possible to produce a perforated metal foil that is hard to tear and has a high tensile strength because the hole itself can have a curved shape without edges (corners).

In addition, paper is used in the production of the metal foil, and the punching waste generated can be completely collected, which is excellent in terms of resource conservation and working environment conservation.

1 is a schematic diagram of a metal foil punching device according to a first embodiment; FIG. Three types of pressure rolls used in the first embodiment. 4 is a schematic diagram of a pair of pressure rolls having a large diameter portion and a small diameter portion used in the first embodiment; FIG. FIG. 4 is a schematic diagram of a winding process after perforation of the metal foil according to the first embodiment; FIG. 2 is a schematic view of a main part of a metal foil punching device according to a second embodiment; 1 is a perforating roll according to Example 1. FIG. FIG. 10 is a development pattern diagram of the top surface of the projections on the surface of the perforating roll according to Example 1; FIG. 2 is an enlarged view of a copper foil after punching according to Example 1 and a paper on which punching debris (copper foil) is adhered. FIG. 5 is a schematic diagram of the surface of a perforating roll according to Example 2; FIG. 10 is an enlarged view of the copper foil after punching and the paper to which punching dust (copper foil) adheres according to Example 2;

<First Embodiment>
1 to 4, a first embodiment of a metal foil punching device 1 and a metal foil punching method according to the present invention will be described in detail below. This metal foil punching device 1 sandwiches a laminate obtained by laminating metal foil and paper between a punching roll and a plurality of pressure rolls, presses the laminate, and punches the laminate to form a large number of holes in the metal foil. (Fig. 1).
1. Schematic Structure of Metal Foil Punching Apparatus FIG. 1 is a schematic diagram of a metal foil punching apparatus 1 according to the present invention. This metal foil punching device 1 punches a metal foil 31 having a thickness of about several μm (eg, 6 μm) to 100 μm such as a copper foil, an aluminum foil, a stainless steel foil, etc., and punches a metal foil having a large number of holes. 1 is a schematic diagram of an apparatus; FIG.

This metal foil punching device 1 has a large number of projections on the surface as will be described in detail in Examples 1 and 2 below, and has a substantially cylindrical punching roll 3 and a roll 3 surrounding it. The metal foil 31 is pressed and punched using a total of five pressure rolls 5a to 5e having a smaller diameter than the perforation roll 3, and the perforated metal foil 35 having a large number of holes is formed. (Fig. 1). Incidentally, the metal foil punching device 1 disclosed in Patent Document 5 uses a total of six pressure rolls as shown in FIG.

In this metal foil punching device 1, only the punching roll 3 is driven to rotate by a driving force (not shown), for example, a motor. Each of the auxiliary rolls 7a-g rotates by being driven by the pressurization. Therefore, only the perforating roll 3 requires a driving force, and the other pressure rolls 5a to 5e and the auxiliary rolls 7a to 7g are driven by the perforating device. Equipment can be manufactured compactly and inexpensively.

A long metal foil 31 such as a copper foil, an aluminum foil, and a stainless steel foil wound around the metal foil roll 13 is guided through a roller 21b so as to come into contact with the surface portion of the perforating roll 3 (see FIG. 1). ).

On the other hand, the long paper 35 wound around the paper roll 17 is guided through the roller 21a so as to come into contact with the surface portion of the pressure roll 5a. This paper 35 is, for example, a long sheet-shaped sheet made of paper (papermaking) as a base material. it is covered. In Example 1 and Example 2, which will be described later, the surface was further treated with silicone to make it slippery.

As the paper 35, it is also possible to use a paper-like (thin plate-like, sheet-like) resin product. In the present application, the term "paper 35" is used so as to clearly distinguish it from the sheet-like (thin plate-like or foil-like) metal foil 31. FIG.

When the paper 35 surface-treated in this way is used, the cellulose fibers that serve as the base material are less likely to scatter during the perforation, and the perforation waste 39 generated by the perforation is fixed to the surface-treated surface and held as it is. Since it can be wound up in a state in which it is held still, the punching waste 39 can be collected almost completely. In addition, since the punching dust 39 does not fly up as dust, it does not contaminate the working environment. In addition, the use of the paper 35, which is made of paper as a base material, is characterized by being inexpensive and eco-friendly since recycled products can be used.

As shown in FIG. 1, a perforating apparatus 1 according to the present invention has a substantially cylindrical perforating roll 3 with a large diameter, for example, a diameter of about 86 mm, in the central portion. There were five small diameter pressure rolls 5a-e. Thus, by using a total of five pressure rolls and using pressure rolls each having a smaller diameter than the diameter of the perforating roll 3 (for example, a pressure roll having a radius of curvature of half or less), The metal foil 31 can be repeatedly pressed and released a total of five times in a state of high linear pressure. Therefore, it is possible to manufacture the punched metal foil 33 having a large number of holes with less burrs and uneven punching.

Here, the metal foil 31 is wound into the apparatus at the portion contacting the perforating roll 3, and the paper 35 is wound at the portion contacting the pressure rolls 5a to 5e (FIG. 1). That is, the laminate obtained by laminating the metal foil 31 and the surface-treated surface of the paper 35 so as to face each other is first wound between the perforating roll 3 and the pressure roll 5a and pressed. (Fig. 1).

The metal foil 31 is in contact with the paper 35 and the perforating roll 3, receives pressure from a total of five pressure rolls 5a to 5e via the paper 35, and is perforated to form a large number of holes. On the other hand, the paper 35 abuts against the pressure rolls 5a to 5e and the metal foil 31, and is fixed by adhering punching dust 39 generated by punching.

The back side portion (non-contact portion) of the metal foil 31 in contact with the surface of the perforating roll 3 is held by the surface-treated paper 35, and is held without positional deviation. While being pressurized by the pressure rolls 5b to 5e, the perforation roll 3 is substantially circled so as to surround it. Therefore, by using the present invention, the metal foil 31 can be almost completely perforated, and a good quality post-punched metal foil 33 having holes with less burrs can be obtained.

The perforated metal foil 33 that has passed through the last pressure roll 5e of the lower portion passes through the roller 21c and is rolled by the rolling roll 11 so that the surface of the perforated portion becomes smooth. is turned (Fig. 1). On the other hand, on the surface of the paper 35 facing the metal foil 31, the punching dust 39 is fixed, and in this state, the paper 35 is wound around the paper roll 19 with punching dust through the rollers 21d and 21f (Fig. 1). .
2. Pressure rolls 5a to e
(1) Schematic Structure of Pressure Rollers 5a-e A total of five pressure rolls 5a-e shown in FIG. 1 will be described in detail (FIGS. 2 and 3). These pressure rolls 5a to 5e have a length of about 650 mm and a diameter of about 15 mm at the central thick portion (portion that may come into contact with the paper 35), and thin portions at both ends (fixed to a jig or the like). The part to be covered) has a length of about 100 mm and a thickness of about 8 mm. The thin portions at both ends of the pressure rolls 5a to e are a well-known technique used for fixing to jigs, so the description is omitted, and the central thick portion will be described in detail (FIGS. 2(b) and 3).

In the first embodiment, three types of rollers having different shapes are used as the five pressure rollers 5a to 5e (FIGS. 2(a) and 2(b)). The pressure roll 5a and the pressure roll 5c, and the pressure roll 5d and the pressure roll 5e have the same shape (FIGS. 2(a) and 2(b)). The pressure roll 5d and the pressure roll 5e are so-called round bar-shaped rolls, and although they have a larger diameter, they are bar-shaped rolls having substantially the same shape as the one already disclosed by the applicant of the present application. Therefore, detailed description is omitted (Patent Document 5).
(2) Large-diameter portion 61 and small-diameter portion 62
The pressure roll 5a and the pressure roll 5c (because these two rolls have the same shape, they may be called the pressure rolls 5a and 5c) and the pressure roll 5b have a large diameter portion 61 and a small diameter portion, respectively. It has a portion 62 (FIG. 2(b)). Each large diameter portion 61 had a diameter of 15 mm and a width of 80 mm, and each small diameter portion 62 had a diameter of 14 mm and a width of 50 mm. That is, the large-diameter portions 61 of the pressure rolls 5a and 5c and the pressure roll 5b are wider than the small-diameter portions 62 (FIGS. 2(b) and 3). The small-diameter portion 62 is formed by cutting the rod-shaped large-diameter portion 61 having an elongated cylindrical shape.
A small diameter portion 62 of the pressure roll 5b (paper 35 and A portion where the metal foil 31 is not pressurized.) correspond to each other (FIGS. 2(b) and 3(a)). In addition, in the portions corresponding to the small diameter portions 62 of the pressure rolls 5a and 5c (the portions where the paper 35 and the metal foil 31 are not pressed), the large diameter portions 61 of the pressure roll 5b (the metal foil along with the perforating roll 3) are provided. 31 and the portion that presses the paper 35) were formed to correspond to each other (FIGS. 2(b) and 3(a)).
Further, the wide large-diameter portion 61 of the pressure rolls 5a and 5c and the wide large-diameter portion 61 of the pressure roll 5b overlap each other (FIG. 3A). By providing the overlapping portion in this way, it is possible to prevent occurrence of insufficiently perforated portions of the metal foil 31 (so-called irregular perforation).
In addition, by using the pressure roll having the large-diameter portion 61 and the small-diameter portion 62, the pressure force can be concentrated on the large-diameter portion 61 for perforation. It is also possible to manufacture a metal foil having substantially circular holes.
That is, the large-diameter portion 61 of one pressure roll 5a, c is formed to correspond to the small-diameter portion 62 of the other pressure roll 5b, and the small-diameter portion 62 of the one pressure roll 5a, c is formed to correspond to the small-diameter portion 62 of the other pressure roll 5b. , corresponding to the large diameter portion 62 of the pressure roll 5b. In addition, the large diameter portions 61 of these pressure rolls 5a-c are wider than the small diameter portions 62, and the large diameter portions 61 of the pressure rolls 5a and 5c and the large diameter portion 61 of the other pressure roll 5b The large-diameter portion 61 of 1 has an overlapping portion.
Note that in the first embodiment shown in FIG. 1, the pressure roll 5a having the large-diameter portions 61 near both ends is used at the inlet for the metal foil 31 and paper 35, but the portions near both ends have a small diameter. Needless to say, the pressure roll 5b that serves as the portion 62 can be used.
Also, although the perforation accuracy is somewhat inferior, instead of the pressure roll c, round-bar-shaped pressure rolls d and e (the pressure roll d and the pressure roll e have the same shape, so they can be used instead of the pressure roll c). It was decided to collectively call pressure rolls d and e.) can also be used. In this case, the pressure rolls having the large diameter portion 61 and the small diameter portion 62 are a pair (two rolls) of the pressure roll 5a and the pressure roll 5b.
In addition, it goes without saying that round bar-shaped pressure rolls d and e can be used at the position of the pressure roll b in FIG. In this case, the pair of pressure rolls having the large-diameter portion 61 and the small-diameter portion 62 have the shapes of the pressure roll 5a and the pressure roll 5b, which is installed to replace the position of the pressure roll 5c in FIG. It becomes a pair.
(3) Coating of the small-diameter portion 61 with an elastic material Conventionally, when a thin metal foil of about several μm (for example, 6 μm) is introduced (rolled up) into a punching device, it is wrinkled or twisted, making it difficult to roll up. There was a manufacturing defect such as
Among at least a pair of pressure rolls having a large diameter portion 61 and a small diameter portion 62, a part of the small diameter portion 62 of the pressure roll (pressure roll 5a in FIG. 1) on the inlet side of the metal foil, for example, It was found that defects during manufacturing can be prevented by coating some of the end portions (the left two portions are shown in FIG. 3(b)) with an elastic body (for example, a resin such as rubber). .
That is, by coating the resin coating 63 on about two portions at both ends of the small-diameter portion 62 of the pressure roll 5a that first comes into contact with the paper 35, defects during manufacturing can be prevented (FIG. 3(b)). As a means for the resin coating 63, specifically, a method of applying a resin (e.g., rubber) to the small diameter portion 62 of the pressure roll 5a and then polishing it to a diameter approximately equal to that of the large diameter portion 61 is used. . Since the technique of the resin coating 63 is a well-known technique, detailed description thereof will be omitted.
3. Auxiliary Rolls Auxiliary rolls 7a to 7g are installed outside the pressure rolls 5a to 5e (positions far from the axis of the perforating roll 3 (FIG. 1)). The auxiliary rolls 7a to 7g are connected to a jig (not shown) via a bracelet-shaped flat cylindrical bearing (hereinafter simply referred to as a bearing) generally used for rotating shafts and the like. is fixed to And it has a function of smoothing the rotation of the pressure rolls 5a to 5e described above and enabling adjustment of the pressure applied to the perforating roll 3, and these are already known technologies. .

As described above, the auxiliary rolls 7a-g are rotated together with the pressure rolls 5a-e by being driven by the perforating roll 3. As shown in FIG. Incidentally, the structure of the auxiliary rolls 7a to 7g is a technique already disclosed in the above-mentioned Patent Document 5, so a detailed description thereof will be omitted.
4. Step of Winding Metal Foil after Perforation The process of winding the metal foil after perforation will be described (FIGS. 1 and 4). After passing the roller 21c, the punched metal foil 33 is adjusted to a tension within a certain range by the up-down swing roller, and is passed through the vacuum chamber 43, which is sucked by the vacuum pump 45, and the pair of adhesive rollers 47a. , to remove a considerable amount of remaining drilling debris 39 .

Then, the burrs on the surface of the perforated portion are rolled by the rolling rolls 11 so as to be smooth, and minute perforating scraps 39 generated during rolling are more completely removed by the pair of adhesive rollers 47b on the second stage, resulting in winding misalignment. In order to prevent this, the perforated metal foil roll 15 is wound up after passing through a commercially available meandering control device 42 .

Therefore, it is possible to completely remove the piercing dust 39 generated during the piercing process, which causes a short circuit in lithium ion batteries and the like. It should be noted that the same manufacturing equipment can be used when an aluminum foil, a stainless steel foil, or the like is used as the metal foil 31 instead of the copper foil.
<Second embodiment>
FIG. 5 is a schematic view of a main part of the metal foil punching device 1 according to the second embodiment. The metal foil 31 and the paper 35 are pressed in order by the pressure roll 9b, the pressure roll 5a1, the pressure roll 9a, the pressure rolls 5b1 and c1.
The main difference from the first embodiment is that although a total of five pressure rolls are used, two of them (a pair) have large diameters (pressure rolls 9a and 9b). 3 is that small diameter rolls (pressure rolls 5a1 to c1) are used.
Then, for example, the pressure roll 9a of FIG. 5 has a large diameter portion 61 and a small diameter portion 62 like the pressure roll 5a of FIG. Further, the pressure roll 9b shown in FIG. 5 has a large diameter portion 61 and a small diameter portion 62 like the pressure roll 5b shown in FIG.
The large-diameter portion 61 of one pressure roll 9a is formed so as to correspond to the small-diameter portion 62 of the other pressure roll 9b, and the small-diameter portion 62 of the pressure roll 9a is formed so as to correspond to the small-diameter portion 62 of the other pressure roll 9b. It was formed so as to correspond to the large diameter portion 62 . In addition, the large-diameter portion 61 of these pressure rolls 9a, b is wider than the small-diameter portion 62, and the large-diameter portion 61 of one pressure roll 9a and the large-diameter portion 61 of the other pressure roll 9b are separated from each other. The diameter portion 61 has overlapping portions.
In addition, some of the small-diameter portions 62 of the pressure roll (pressure roll 9b, indicated by an arrow in FIG. 5) on the entrance side of the metal foil 31 and the paper 35 are covered with an elastic body (for example, a resin such as rubber). Coated. The small-diameter pressure rolls 5a1 to c1 in FIG. 5 are round bar-shaped without the large-diameter portion 61 and the small-diameter portion 62, similarly to the pressure rolls 5d and 5e in FIG. Since the other parts have the same structure as the first embodiment, detailed description thereof will be omitted.

The pair of pressure rolls 9a and 9b has a larger diameter than that of the first embodiment, and as a result, the pressure can be increased, so the auxiliary rolls are omitted. Needless to say, there is no problem even if auxiliary rolls are additionally installed outside the pressure rolls 9a and 9b (positions far from the axis of the perforating roll 3 (FIG. 5)).

The production of a metal foil having fine, substantially rhomboidal holes will be described (FIGS. 6 to 9). In order to manufacture the metal foil, a cylindrical perforating roll 3 having a diameter of 86 mm and a length of 220 mm was used (Fig. 6(a)). The surface of the perforating roll 3 has a large number of minute protrusions 25, the upper surface 25a of which is substantially rhombic (FIG. 6(b)). Enlarged photographs in Example 1 and Example 2 below were all taken with a commercially available digiscope (approximately 45 times).

FIG. 7 shows a pattern diagram of the upper surface 25a of the minute protrusions 25 formed on the surface of the perforating roll 3 used in Example 1. As shown in FIG. The pitch of the upper surface 25a is rhombic with a of about 0.27 mm and b of about 0.15 mm (FIG. 7(c)), c of about 0.26 mm in the longitudinal direction, and about 0 of d in the width direction. 0.15 mm and a height of about 0.1 mm (for example, 0.12 mm). That is, on the surface of the perforating roll 3, minute projections 25 having a shape of a truncated quadrangular pyramid and having a substantially diamond-shaped upper surface 25a are provided at regular intervals.

The perforating roll 3 has one or more cutting blades 27 (for example, , a grindstone for special processing, etc.), the grooves 23 and the projections 25 were formed at the same time. Since the upper surface 25a of the projection 25 is formed on the surface of a cylinder, strictly speaking, it is a curved surface. The same applies to the name "substantially circular" in Example 2.).
The punching roll 3 after cutting was coated with diamond-like carbon (DLC coating, 3500 to 5000 HMV) for the purpose of increasing hardness and lowering the coefficient of friction (mainly preventing adhesion of the metal foil 31). The method for manufacturing the perforating roll 3 has already been described in Patent Document 5 mentioned above, so a detailed description thereof will be omitted.

The perforating roll 3 having the upper surface 25a of the projections 25 of the first embodiment was installed in the apparatus of the above-described first embodiment, and a perforation experiment was performed using a rolled copper foil having a thickness of 10 μm and a width of 200 mm. The figure shows the result of perforating a copper foil using a paper 35 with a thickness of about 150 μm, one surface of which is surface-treated with a polyethylene thin film and silicone (for example, product number: KP-110 manufactured by Lintec). 8.

As shown in FIG. 8, substantially diamond-shaped holes 32 are formed in the copper foil after punching (FIG. 8(a)), and punching debris 39 (copper foil) generated by punching is present in the paper 35. It can be seen that it is fixed (FIG. 8(b)). In addition, compared to FIG. 5 of Patent Document 5 described above, it can be seen that the substantially diamond-shaped holes 32 are formed with extremely high precision and almost no burrs during drilling.

Needless to say, the shape of the holes 32 can be changed by making the upper surface 25a of the perforating roll 3 substantially rhombus a square, a rectangle, or other polygons.

Manufacture of a metal foil having minute, substantially circular holes will be described (FIGS. 9 and 10). In order to manufacture the metal foil with the holes having substantially circular shapes, the entire metal foil has a columnar shape as in Example 1, and has a large number of minute columnar projections 25 on its surface. , and a perforating roll 3 having a substantially circular upper surface 25a (FIGS. 9A and 9B).

FIG. 9A shows a development pattern diagram of the upper surface 25a of the convex portion 25 formed on the surface of the perforating roll 3 used in Example 2. As shown in FIG. In FIG. 9( a ), the upper surface 25 a having a minute, substantially circular shape has its center point at the vertex of an equilateral triangle, and has a diameter of 0.5 mm, a pitch of 0.8 mm, and a pitch of 0.8 mm. It is as small as about 0.1 mm (0.12 mm, for example) in height. On the surface of the perforating roll 3, projections 25 having a substantially cylindrical minute shape and having a substantially circular upper surface 25a are arranged at regular intervals. That is, in Example 2, the purpose was to form the holes 32 having a diameter of 0.5 mm and a pitch of 0.8 mm and having a substantially circular shape.

As the perforating roll 3 of Example 2, a SUS440C column (cylinder) whose surface was ground in advance was used. Then, after chemically forming a large number of small cylindrical projections 25 and grooves 23 on the surface by etching, diamond-like carbon coating (DLC coating, 3500 to 5000 HMV) was applied (FIG. 9). (b)).

The punching roll 3 with the upper surface 25a of the convex portion 25 being substantially circular was installed in the apparatus of the first embodiment described above, and the same rolled copper foil and paper 35 as in Example 1 were used to punch holes. The results are shown in FIG. show.

As shown in FIG. 10, substantially circular holes 32 are formed in the copper foil after punching (FIG. 10(a)) in which almost no burrs are observed at the time of punching. It can be seen that substantially circular punching debris 39 (copper foil) is fixed (FIG. 10(b)).

Needless to say, the shape of the hole 32 can be changed by forming the upper surface 25a of the projection 25 on the surface of the substantially circular perforating roll 3 into an elliptical shape.

The metal foil produced by the present invention can be used as a current collector such as a positive electrode plate or a negative electrode plate for non-aqueous secondary batteries such as lithium ion batteries.

1 metal foil punching device 3 punching rolls 5a, b, c, d, e pressure rolls (Fig. 1)
5a1, b1, c1 Pressure roll (Fig. 5)
7a, b, c, d, e, f, g auxiliary roll 8 valley 9a, b pressure roll 10a, b auxiliary roll 11 pressure roll 13 metal foil roll 15 perforated metal foil roll 17 paper roll 19 paper roll with perforation waste 21a , b, c, d, e Roller 23 Groove 25 Protrusion 25a Upper surface (substantially diamond-shaped, substantially circular)
25b side (substantially trapezoidal)
25c edge part 27 cutting blade 31 metal foil 32 hole 33 metal foil after punching 34 uncoated part 35 paper 37 paper with punching dust 39 punching dust 41 up-down swing roller 42 meandering control device 43 vacuum chamber 45 vacuum pump 47a, b adhesive Rollers 49a, b Adhesive belt 51 Fixing plate 52 Vertical frame 53 Horizontal frame 54a-f Rotary shaft 61 Large diameter portion 62 Small diameter portion
63 resin coat

Claims (6)

A metal foil punching device for forming a large number of holes in a metal foil by sandwiching a laminate of a metal foil and paper between a punching roll and a plurality of pressure rolls, applying pressure, and punching the metal foil. hand,
The surface of the perforating roll has a large number of protrusions,
The plurality of pressure rolls are present so as to surround the perforation roll,
At least one pair of the pressure rolls has a large diameter portion and a small diameter portion,
The large-diameter portion of one pressure roll is formed to correspond to the small-diameter portion of the other pressure roll,
The small diameter portion of one pressure roll is formed to correspond to the large diameter portion of the other pressure roll,
The metal foil is
contacting the paper and the convex portion of the perforating roll;
A large number of holes are formed by receiving pressure from the plurality of pressure rolls via the paper and the upper surface of the convex portion, and
Said paper
contacting the pressure roll and the metal foil,
A punching device for metal foil, wherein the punching waste generated by the punching is fixed. The convex portion is
2. The metal foil punching apparatus according to claim 1, wherein the punch has a shape of a truncated quadrangular pyramid, the upper surface of which is a rhombus. The convex portion is
2. The metal foil punching apparatus according to claim 1, wherein the punch has a cylindrical shape and the upper surface thereof is substantially circular. The large diameter portion is wider than the small diameter portion,
2. The metal foil punching apparatus according to claim 1, wherein the large-diameter portion of the one pressure roll and the large-diameter portion of the other pressure roll have overlapping portions. 2. The metal foil punching device according to claim 1, wherein the small diameter portion of the pressure roll on the inlet side of the metal foil is coated with an elastic material. A method for perforating a metal foil, wherein a laminate obtained by laminating a metal foil and paper is sandwiched between a perforation roll and a plurality of pressure rolls, pressed, and perforated to form a large number of holes in the metal foil. hand,
The surface of the perforating roll has a large number of protrusions,
The plurality of pressure rolls are present so as to surround the perforation roll,
At least one pair of the pressure rolls has a large diameter portion and a small diameter portion,
The large-diameter portion of one pressure roll is formed to correspond to the small-diameter portion of the other pressure roll,
The small diameter portion of one pressure roll is formed to correspond to the large diameter portion of the other pressure roll,
The metal foil is
contacting the paper and the convex portion of the perforating roll;
A large number of holes are formed by receiving pressure from the plurality of pressure rolls via the paper and the upper surface of the convex portion, and
Said paper
contacting the pressure roll and the metal foil,
A method of punching a metal foil, wherein the punching debris generated by the punching is fixed.

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