JPH08236120A - Manufacture of porous electrolytic metal foil and secondary battery electrode using this electrolytic metal foil - Google Patents

Abstract

PURPOSE: To provide a method of continuously manufacturing a porous electrolytic metal foil and a secondary battery electrode using this porous electrolytic metal foil in a current collecting board. CONSTITUTION: A porous electrolytic metal foil is manufactured in such a way that at least 14nm thick oxide film is formed on the surface of a drum cathode exposed by peeling off a metal foil layer electrolytically deposited on the surface of the drum cathode by using the drum cathode and an anode, then electrolytically depositing the metal foil on the oxide film. An electrode is manufactured by using the porous electrolytic metal foil 1 having through holes 2 in the thickness direction as a current collecting board and filling an electrode mix agent 3 such as an active material mix agent in the current collecting board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a porous electrolytic metal foil and an electrode for a secondary battery using the electrolytic metal foil as a current collecting substrate. More specifically, a mixture for electrodes is provided on the current collecting substrate. The present invention relates to a secondary battery electrode that is firmly supported and is likely to uniformly undergo an electron transfer reaction during charge / discharge cycles, and a method for producing a current collecting substrate used therefor by electrolytic plating.

[0002]

2. Description of the Related Art In recent years, with the popularization of portable electronic equipment such as video cameras and notebook computers, there has been an increasing demand for small-sized, high-capacity secondary batteries as their power sources. Most of the secondary batteries currently used are nickel-cadmium batteries using alkaline electrolyte,
This battery has a battery voltage of about 1.2V. Therefore, nickel-hydrogen batteries have been attracting attention as batteries of higher output, and development of lithium batteries is in progress.

Nickel-hydrogen batteries operate with hydrogen as the negative electrode active material. Then, a negative electrode is formed by supporting a hydrogen storage alloy capable of reversibly storing and releasing hydrogen on a current collecting substrate, and a positive electrode active material such as nickel hydroxide is also supported on the current collecting substrate to form a positive electrode. Is configured. For example, in the production of a negative electrode for a nickel-hydrogen battery, a predetermined amount of a hydrogen storage alloy powder, a conductive material powder such as Ni, and a binding material powder such as polyvinylidene fluoride is mixed to form a mixed powder, and, for example, carboxymethylcellulose. Slurry which is a mixture for the negative electrode is prepared by adding the aqueous solution of the above, and the slurry is used as a punching Ni sheet having a desired aperture ratio or a Ni foam sheet having a desired porosity or Ni.
Filling a current collecting substrate such as a sintered body of powder, drying, rolling,
The heat treatment is sequentially performed so that the above-mentioned mixture is carried in the state of being closely adhered to the surface of the current collecting substrate and the internal voids.

Further, in the case of producing a positive electrode, a predetermined amount of a powder of nickel hydroxide, which is a positive electrode active material, and a conductive material such as Ni powder are mixed into a mixed powder, and a predetermined amount of an aqueous solution of carboxymethyl cellulose is added thereto. After the mixture is added and the whole is stirred to prepare a slurry mixture for the positive electrode, the mixture for the positive electrode is filled in a current collecting substrate such as a Ni foam sheet,
Drying and rolling are sequentially performed to support the positive electrode mixture on the current collecting substrate.

On the other hand, lithium batteries are roughly classified into metal lithium batteries and lithium ion batteries. In the case of a metallic lithium battery, the negative electrode is composed of metallic lithium, the positive electrode is composed of a positive electrode active material such as LiCoO ₂ supported on a current collecting substrate, and in the case of a lithium ion battery, the positive electrode is the same as above. Although it has a constitution, the negative electrode can absorb and release lithium ions, for example, carbon (C).
The one in which the current collecting substrate is carried is used.

In the former of these types of lithium batteries, dendride-like lithium recrystallizes on the surface of metallic lithium as a negative electrode during charging and grows as the charge-discharge cycle progresses. In addition to the problem that the cycle life of the battery is shortened, in the worst case, the grown lithium recrystal may break through the separator interposed between the positive electrode and the negative electrode to cause a short circuit accident.

For these reasons, with respect to the lithium battery, research and development of a lithium ion battery in which a negative electrode supporting C is incorporated in a current collecting substrate is currently underway. This negative electrode does not have the same problems during charge / discharge cycles as in the case of the metallic lithium negative electrode. By the way, in the case of manufacturing a positive electrode of a lithium battery, first, for example, L, which is a positive electrode active material, is used.
A predetermined amount of iCoO ₂ powder, a conductive material such as C powder, and a binder such as polyvinylidene fluoride powder is mixed to form a mixed powder, and the mixed powder is mixed with a non-conductive material such as N-methylpyrrolidone. A paste-like kneaded material, which is a mixture for the positive electrode, is prepared by adding a predetermined amount of a water solvent and thoroughly kneading. Then, this kneaded product is applied to the surface of a current collector substrate made of a metal foil or alloy foil such as Ni, Cu, Ti-Al foil formed by a rolling method, and then dried to form the positive electrode on the current collector substrate. The mixture is firmly adhered and integrated to be supported.

On the other hand, in the production of a negative electrode of a lithium ion battery, carbon fiber itself in the form of fiber, woven fabric or felt may be used as C, but in general, the powder of C and the above-mentioned binder are used. A predetermined amount of the powder of the adhering material and the non-aqueous solvent is mixed to prepare a paste-like mixture for the negative electrode, and the mixture is applied to the current collector substrate made of the metal foil as described above, dried and then pressure-bonded. Is carried.

[0009]

By the way, an important problem for each of the above-mentioned positive electrode and negative electrode is that the above-mentioned mixture for positive electrode or negative electrode (hereinafter referred to as electrode mixture) is incorporated in a battery or during a charge / discharge cycle. That is, the mixture) does not come off from the current collecting substrate. This is because when these mixture materials are peeled off from the current collecting substrate, polarization starts to increase in the course of charge / discharge cycles, which causes deterioration of cycle life characteristics.

When a Ni foam sheet is used as a current collector substrate such as a hydrogen / nickel battery, the electrode mixture is filled up to the inside of the sheet, so that peeling does not easily occur. However, the pore size of such a foam sheet is about 100 μm, and the pore size is too large for the entire sheet. Therefore, it is preferable in that the filling amount of the electrode mixture can be increased, and is also useful for preventing the electrode mixture from peeling off, but on the other hand, the mechanical strength of the sheet becomes small, so it is easy to tear. Further, there is a problem that the filling of the electrode mixture becomes non-uniform and the electron transfer reaction during the charge / discharge cycle tends to become non-uniform.

Further, when a punching metal sheet in which openings having a predetermined diameter are regularly formed in a zigzag pattern is used as a current collector substrate, the openings are also too large for the entire sheet. In addition, there is a problem in that the production thereof causes an increase in cost because punching has to be performed on the non-perforated sheet. Further, although expanded metal may be used for the current collector substrate, this expanded metal must be specially processed on the non-perforated sheet as in the case of the punching metal sheet. It has the problem of cost increase compared to punching metal sheets.

On the other hand, in the case of a positive electrode or a negative electrode of a lithium battery, a metal foil formed by a rolling method is usually used as a current collecting substrate, and a paste such as an electrode mixture is simply applied on its smooth surface. Since they are simply pressure-bonded to carry them, peeling is likely to occur. Therefore, at least the surface of the metal foil is appropriately roughened, and the roughened surface exerts an anchoring effect on the electrode mixture carried by the roughened surface, and the electrode mixture and the collector substrate surface Measures are taken to increase the adhesion strength with. Further, a treatment for making the metal foil porous is also performed.

In that case, as a roughening method, for example, a mechanical method such as press working or sandblasting, or, for example, for a copper foil, ammonia water, hydrogen peroxide water (3%) and water are used. 50m nitric acid for an etchant whose volume ratio is 1: 4: 5 and for nickel foil
1. Etching using an etchant such as 50 ml of glacial acetic acid, or as is applied to a copper foil for printed circuit boards, coarse crystals are deposited on the surface of a metal foil by electrodeposition. It is known that the surface is made flat.

However, in the case of any of the above-mentioned methods, since it is a treatment newly applied to a metal foil which has already been foil-formed, the number of steps is increased, and as a result,
There arises a problem that the manufacturing cost of the obtained current collecting substrate is increased, which in turn causes an increase in electrode cost. The present invention solves the above problems in the metal foil that has been conventionally used as a collector substrate for a secondary battery,
At the same time as foil making, a metal foil having a porous structure is manufactured by electrolytic plating, and by using the electrolytic metal foil as a current collector, not only the manufacturing cost can be reduced, but also the electrodes are incorporated. Another object of the present invention is to provide an electrode having improved battery cycle life characteristics.

[0015]

In order to achieve the above object, in the present invention, an anode body and a moving cathode body are immersed in an electrolytic solution containing metal ions, and the moving card body is moved to move the anode body. A metal foil layer is continuously formed by electrodepositing a metal on the surface of the moving cathode body by conducting an electrolytic reaction between the body and the moving cathode body while moving the moving cathode body. A method for continuously producing an electrolytic metal foil by continuously peeling the metal foil layer from, wherein the exposed surface of the moving cathode body exposed after peeling the metal foil layer is electrolytically oxidized there. Forming an oxide film with a thickness of at least 14 nm on the
There is provided a method for producing a porous electrolytic metal foil, which comprises forming the metal foil layer on the oxide film.

Further, the electrolytic metal foil manufactured by the above-mentioned method, which is a porous electrolytic metal foil having communication holes in the thickness direction is used as a current collector substrate, and the electrode mixture is carried on the current collector substrate. An electrode for a secondary battery is provided. First, FIG. 1 is a schematic sectional view schematically showing an example of a sectional structure of an electrode of the present invention. In the figure, a current collecting substrate 1 made of a porous electro-deposited metal foil having a thickness of 10 to 100 μm, which is manufactured by a method described later, has a communication hole 2 penetrating from its surface 1a to another surface 1b in a three-dimensional mesh shape. It has a structure. The surfaces 1a and 1b of the porous electro-deposited metal foil 1 are roughened, and the electrode mixture 3 is carried therein in a state of slightly digging into the inside from the opening 2a of the communication hole 2. .

The diameter of the opening 2a of the communication hole 2 varies depending on the thickness of the porous electrolytic metal foil 1, but is 0.1 to 10 μm.
It is preferable to be within the range of m, and such a communication hole has a unit area (1 mm ² ) on the surface of the electrolytic metal foil 1.
It is preferable that 1 to 500 pieces are distributed per one. In addition,
The communication holes 2 are formed randomly, and not all the communication holes are present as through holes, and some of them may be closed on the way.

When the diameter of the communication holes 2 is smaller than 0.1 μm, the electrode mixture 3 cannot be smoothly filled into the communication holes 2 even if the electrode mixture is applied and pressure-bonded thereto. Therefore, the anchor effect is reduced, and the adhesion strength between the electrode mixture 3 and the current collecting substrate 1 is reduced. Also, the communication hole 2
When the diameter is larger than 10 μm, the mechanical strength of the current collector substrate 1 is lowered, and for example, in foil formation to be described later, there is an inconvenience such as breakage when peeled from the surface of the moving cathode body.

The distribution density of these communication holes 2 is 1 /
If it is smaller than mm ^2, the surface of the current collector substrate 1a, 1b is roughened to have a surface roughness described later, and thus the electrode mixture 3
Although it is carried on the surfaces 1a and 1b, the adhesion strength is weak and the film easily peels off. When the distribution density is greater than 500 pieces / mm ² , the adhesion strength between the electrode mixture 3 and the current collecting substrate 1 is improved, but the current collecting substrate 1
However, as a whole, it has an excessively porous structure, and as described above, its mechanical strength is lowered, which is inconvenient.

The roughness of the surfaces 1a and 1b also varies depending on the thickness of the porous electrolytic metal foil, but JIS B06
The roughness (Rz) defined by 01 is preferably 2 to 40 μm. When it is less than 2 μm, good adhesion strength with the electrode mixture is not exhibited, and as described above,
Generally, a current collector substrate having a thickness of about 10 to 100 μm is used, so that the surface roughness of the current collector substrate needs to be limited to 40 μm.

The diameter of the opening of the communicating hole, the distribution density of the communicating hole, and the surface roughness of the current collecting substrate are the thickness of the current collecting substrate to be used and the particle size of each component powder constituting the electrode mixture. The diameter of the communication hole is 0.1 to 10 μm for a current collecting substrate having a thickness of 10 to 100 μm.
Distribution density is 300-400 / mm ² , surface roughness is 10
30 μm is particularly preferable.

In the electrode of the present invention, the electrode mixture 3 carried on the surfaces 1a and 1b of the above-mentioned current collecting substrate 1 is appropriately selected in relation to the constituent battery. For example, in the case of the positive electrode of a nickel-hydrogen battery, the above-mentioned positive electrode mixture containing nickel hydroxide powder as an active material is carried on the surface of the above-mentioned current collector substrate, and in the case of the negative electrode, hydrogen is used. The negative electrode mixture containing the storage alloy powder as the main component is carried.

In the case of the positive electrode of a lithium battery, the active material powder such as lithium vanadium pentoxide, lithium manganese oxide, lithium manganese oxide, and lithium cobalt oxide is the main component on the surface of the above-mentioned current collector substrate. In the case of the negative electrode, the main component is a powder made of C such as pyrolytic carbon, coke, graphite, glassy carbon, resin fired body, activated carbon, carbon fiber flakes and powder. The negative electrode material mixture is carried.

The current collecting substrate used for the electrode of the present invention is continuously manufactured as a porous electrolytic metal foil by operating the following apparatus. FIG. 2 is a schematic view showing an example of an apparatus used when manufacturing the current collecting substrate (electrolytic metal foil) of the present invention. Further, FIG. 3 is a schematic diagram showing another example of the apparatus.
In FIG. 2, an electrolytic bath 4 contains an electrolytic solution 5 containing metal ions, which is a raw material of an electrolytic metal foil for manufacturing,
An anode body 6 is installed in the electrolyte solution 5, and a drum cathode body 7 is arranged so as to face the anode body 6 with a part of the drum cathode body 7 immersed in the electrolyte solution 5.

While rotating the drum cathode body 7 in the direction of the arrow p to move the surface thereof sequentially into the electrolytic solution 5, the electrolysis is performed from the distributor 9 to the gap 8 between the anode body 6 and the drum cathode body 7. While continuing to supply the liquid 5, an electric current is applied between the anode body 6 and the drum cathode body 7 to proceed the electrolytic reaction. Further, in the case of the apparatus example of FIG. 3, a belt cathode body 7 ′ is used instead of the drum cathode body 7 of FIG.
By circulatingly moving in the direction, the surface thereof is sequentially moved in the electrolytic solution 5.

In the present invention, the drum cathode body 7 and the belt cathode body 7'described above are called moving cathode bodies because the surface on which the electrolytic metal foil is formed is moving. The metal ions are electrodeposited on the surface of the drum cathode body 7 or the belt cathode body 7 ', and there is a metal foil layer whose thickness is gradually increased in the moving direction of the surface of the drum cathode body 7 or the belt cathode body 7'. It is formed continuously. And
This thin metal layer is continuously peeled off from the surface of the drum cathode body 7 or the belt cathode body 7'when it comes out of the electrolytic solution, and the thin metal layer is formed on the winding roll 11 via the rolls 10a and 10b. It is wound up as 1.

In the method of the present invention, the exposed surface 7a exposed on the drum cathode body 7 or the belt cathode body 7'by peeling the metal foil layer from the surface of the drum cathode body 7 or the belt cathode body 7 '. , 7'a is equipped with an oxide film forming device A, which will be described later.
By operating the exposed surface 7a, 7'a until the exposed surface 7a, 7'a is immersed in the electrolyte solution 5 again,
7'a is electrolytically oxidized and at least 14 nm thick
Oxide film is formed.

When the above-mentioned metal foil layer is formed on the surface of the drum cathode body 7 or the belt cathode body 7'with the oxide film formed thereon, the metal foil layer has a porous structure having communicating holes. . Then, when the metal foil layer is peeled from the moving cathode body such as the drum cathode body 7 or the belt cathode body 7'to form an electrolytic metal foil, the electrolytic metal foil has a surface (S surface) on the moving cathode body side and its opposite side. The surface on the side (M surface) is rough, and the surface on the opposite side has a higher surface roughness than the surface on the moving cathode body side.

At this time, the thickness of the oxide film formed is 14
When the thickness is less than 10 nm, the metal foil layer formed thereon is unlikely to have an appropriate porous structure having the above-mentioned communicating holes and its distribution density and surface roughness, and therefore, the above-mentioned electrode mixture is preferable. As a result, the performance of the current collecting substrate that is carried with adhesion strength is deteriorated. However, if the thickness of this oxide film is too thick, the metal foil layer formed on it will have an excessively porous structure, its mechanical strength will decrease, and it will break when peeled from the moving cathode body. Since inconvenience frequently occurs, the upper limit of the thickness is 100n.
It is preferably m.

The apparatus A for forming an oxide film having such a function on the exposed surface of the moving cathode body is a holding means for holding the electrolytically treated liquid for electrolytic oxidation so as to contact the exposed surface of the moving cathode body. A counter electrode disposed in the holding means opposite the exposed surface of the moving cathode body;
And a supply means for supplying the electrolytic treatment liquid to the holding means.

The anode body 6 is usually made of lead, and the moving cathode bodies 7, 7'at least have a surface of stainless steel, Ti, Cr, Al or Cr-Al.
It is made of alloy. In this device A, while the operation of the moving cathode body is not stopped, electricity is applied between the anode body and the moving cathode body to continue the electroplating to form the metal foil layer on the surface thereof, By continuously supplying the electrolytic treatment liquid to the holding means and bringing the electrolytic treatment liquid into contact with the exposed surface of the moving cathode body, an electric current is applied between the moving cathode body and the counter electrode body to expose the exposed surface. Anodize.

At this time, between the operating potential of the anode body, the operating potential of the moving cathode body and the operating potential of the counter electrode body, the operating potential is reduced in this order. This is because when the operating potential does not satisfy the above relationship, the exposed surface of the moving cathode body is not electrolytically oxidized and an oxide film is not formed there. Further, the formation of the oxide film by the device A may be performed continuously or intermittently.

When the metal foil layer formed by electrodeposition is peeled from the surface of the moving cathode body, a part of the oxide film is also removed to the metal foil layer side at the same time. Since the metal foil layer formed on this oxide film does not have the proper porous structure as described above, the oxide film is continuously formed to complement this thinning state. It needs to be done intermittently or intermittently.

As a method of operating the device A, a constant current method and a constant voltage method can be applied. When the constant voltage method is applied among these methods, the amount of the oxide film removed from the surface of the moving cathode body can be automatically and immediately supplemented, and the thickness of the oxide film can be increased more than necessary. This is preferable because it can suppress the situation that the spores grow.

A specific example of the above-mentioned device A will be described with reference to the drawings.
Reveal First, FIG.₁The drum cathode body 7
FIG. 3 is a partially cutaway perspective view showing a state of being attached to the exposed surface 7a of
is there. This device A has a shaft 12 for mounting the device at the center.
And has a surface facing the drum cathode body 7 during electrolytic oxidation treatment.
Conductive roll 13, which functions as a counter electrode,
Electrolytically treated liquid holding means arranged so as to surround the electrically conductive roll
14 and this electrolytic treatment liquid holding means for electrolytic oxidation
Treatment for supplying the electrolytic treatment liquid 15a used as
The liquid supply means 15 is composed of a pipe. Soshi
The electrolytic treatment liquid holding means 14 is a drum cover indicated by phantom lines.
While in contact with the exposed surface 7a of the sword body 7,
To rotatably support the shaft 12 by means not shown.
Device A ₁As shown in Fig. 2, the entire
It is attached to the exposed surface 7a of the card body 7.

As the conductive roll 13, a roll made entirely of a material having corrosion resistance such as titanium, nickel, chromium, copper, and stainless, or the surface of these materials, for example, silver, silver alloy, gold, gold alloy It is also possible to use a material such as palladium, palladium alloy, etc., which is coated with a material that has electrical conductivity and at the same time has corrosion resistance to the electrolytic treatment liquid 15a used for forming the oxide film. In addition, the surface of the roll made of non-conductive plastic material such as polypropylene or polyvinyl chloride is covered with a foil or wire or mesh made of a material having conductivity and corrosion resistance, or the roll surface has conductivity and corrosion resistance. It is possible to use a material obtained by plating, spraying, or coating a material having. In short, at least the surface of the roll having conductivity and corrosion resistance is used as a counter electrode for electrolytic oxidation of the drum cathode surface.

The electrolytic treatment liquid holding means 14 surrounding the conductive roll (counter electrode) 13 has liquid permeability and appropriate elasticity. The electrolytic treatment liquid holding means 14 is formed by coating the periphery of the conductive roll 13 with a material having corrosion resistance to the electrolytic treatment liquid used, for example, polyurethane, polyvinyl formal or polyester felt, non-woven fabric, split yarn or the like. To be done.

Above the electrolytic treatment liquid holding means 14,
A plurality of openings 15b in the axial direction of the electrolytic treatment liquid holding means 14
Is disposed as an electrolytic treatment liquid supply means, and a predetermined electrolytic treatment liquid 15a is supplied to the pipe 15 by a pump 15c. The electrolytic treatment liquid 15a to be supplied is not particularly limited, but one that does not harm the production of the metal foil layer even when mixed with the electrolytic solution used for the production of the metal foil layer is used. , The same as the electrolyte currently used to deposit metal on the surface of the drum cathode body in the production of the metal foil layer, or the same as the electrolyte but different in the component ratio Can be used.

As the electrolytic solution, for example, an aqueous solution of copper sulfate is used when manufacturing an electrolytic copper foil, and an aqueous solution of nickel sulfate or an aqueous solution of nickel sulfamate is used when manufacturing an electrolytic nickel foil. Four
AlCl ₃ -Li described in JP-A-8-4460
AlH ₄ -tetrahydrofuran bath and NaF · 2Al (C
And the like may be used ₂ H ₅ O) ₃ · 4 toluene bath.

As the electrolytic treatment liquid 15a, it is also possible to use a liquid which does not contain metal ions to be electrodeposited on the drum cathode body 7. Examples of such electrolytic treatment liquid include acidic aqueous solutions such as sulfuric acid aqueous solution, phosphoric acid aqueous solution, hydrochloric acid aqueous solution, sodium sulfate, potassium sulfate,
A neutral aqueous solution in which sodium chloride, potassium chloride, etc. are dissolved can be used. Above all, it is preferable to use a sulfuric acid aqueous solution when manufacturing an electrolytic copper foil using a copper sulfate electrolytic solution.

The means for supplying the electrolytic treatment liquid 15a is not limited to the above-mentioned pipe type, and for example,
The conductive roll 13 is a hollow body, a large number of openings are formed in the peripheral surface thereof, and the electrolytic treatment liquid 15 is provided in the hollow portion of the conductive roll 13.
By supplying a, the electrolytic treatment liquid 15a may be supplied from the inside to the electrolytic treatment liquid holding means 14 through the opening of the peripheral surface thereof.

When the apparatus A ₁ is used, the oxide film on the exposed surface 7a of the drum cathode body 7 is formed as follows. First, the electrolytic treatment solution holding means 14 of the apparatus A ₁ is brought into contact with the exposed surface 7a of the drum cathode body 7 rotating as indicated by the arrow p while giving elasticity. Therefore, the electrolytic treatment liquid holding means 14 automatically rotates in the direction of arrow r in the figure. While maintaining this state, a predetermined electrolytic treatment liquid 15a is supplied to the pipe (electrolytic treatment liquid supply means) 15.

The electrolytically treated liquid 15a is dropped from the opening 15b to the electrolytically treated liquid holding means 14 so that the electrolytically treated liquid holding means 14 is filled.
It is impregnated up to the inside and is retained there. As a result, the conductive roll (counter electrode for electrolytic oxidation) 13 and the exposed surface 7a of the drum cathode body 7 are brought into conduction via the electrolytic treatment liquid 15a. Next, the terminals 13a, 13a attached to the conductive roll 13 are connected to the negative side of the power source (not shown), and the exposed surface 7a of the drum cathode body 7 is connected to the positive side of the power source, and the conductive roll 13 and the drum cathode are connected. An electrolytic current is passed between the exposed surfaces 7a of the body to anodize the exposed surfaces 7a. At this time, the conductive roll (counter electrode) 13 is energized in a state in which the potential is lower than the potential when the metal foil layer is formed on the surface of the drum cathode body in the electrolytic cell, and at the same time, the electrolytic cell is formed. The electric potential of the anode body located inside is higher than that of the drum cathode body. When the potential of the drum cathode body is higher than that of the anode body, metal is not deposited on the surface of the drum cathode body, or electricity is applied so that the potential of the conductive roll becomes higher than the potential of the drum cathode body. This is because the conductive roll 13 becomes a positive pole and the exposed surface 7a of the drum cathode body 7 becomes a negative pole, so that the exposed surface 7a of the drum cathode body 7 is not electrolytically oxidized.

At this time, an oxide film having a desired thickness is formed on the exposed surface 7a by appropriately selecting the rotation speed of the drum cathode body 7 and the operating potential of the conductive roll (counter electrode body). . In this device A ₁ , the width of the electrolytic treatment liquid holding means 14 is made narrower than the width of the drum cathode body 7, and both side portions 7b, 7b of the exposed surface 7a of the drum cathode body 7 are not electrolytically oxidized. Is preferred.

The metal foil layer directly formed on the both side portions 7b, 7b has a mechanical strength higher than that of the metal foil layer having a porous structure formed on the oxide film formed by the apparatus A ₁ . Therefore, when the metal foil layer is peeled off from the drum cathode body, the peeling start point is the portion of the metal foil layer formed on the both side portions 7b, 7b, so that the metal foil layer is broken during the peeling process. This is because the situation can be prevented.

FIG. 5 is a partially cutaway perspective view showing another apparatus A ₂ mounted on the exposed surface 7a of the drum cathode body 7. In the case of this device A ₂ , the electrolytic treatment liquid holding means 16
Is a box-shaped container, one surface of which is open, and the opening 16a is arranged in liquid-tight contact with or in close proximity to the exposed surface 7a of the drum cathode body 7. Therefore, the portions where both side portions 16b, 16b of the container 16 are in sliding contact with or in close proximity to the exposed surface 7a of the drum cathode body 7 are curved surfaces that match the curvature of the exposed surface 7a of the drum cathode body 7.

The width of the container 16 is narrower than that of the drum cathode body 7 for the same reason as the case of the electrolytic solution holding means 15 of the apparatus A _1.
Both side portions 7b and 7b of the exposed surface 7a of the above are not electrolytically oxidized. The container 16 is preferably made of a material having corrosion resistance to the electrolytic treatment liquid used, such as polyvinyl chloride or polypropylene.

Further, when the container 16 is placed in sliding contact with the exposed surface 7a of the drum cathode body 7, the abrasion resistance is improved. Materials with lubricity and elasticity, such as polyethylene,
The container 16 is preferably made of polyester, polyurethane, silicone rubber or the like. A counter electrode 17 for electrolytic oxidation, which is made of, for example, titanium or stainless steel, is arranged in the container 16.
The exposed surface 7a of the drum cathode body 7 exposed to the inside of the container 16 through the opening 16a.

An electrolytic treatment liquid supply pipe 18a is attached to the side wall of the container 16, and an electrolytic treatment liquid discharge pipe 18b is attached to the upper wall of the container 16 so that the electrolytic treatment liquid supply means 18 can be provided between them. It is configured. The electrolytic treatment liquid used for forming the oxide film is supplied into the container 16 from the supply pipe 18a to fill the inside of the container 16, covers the exposed surface 7a of the drum cathode body 7, and flows out of the system through the discharge pipe 18b. .

By passing an electric current between the counter electrode body 17 and the drum cathode body 7 while flowing the electrolytic treatment liquid into the vessel 16, the exposed surface 7a of the drum cathode body exposed from the opening 16a of the container 16 is electrolyzed. Can be oxidized.
At this time, if the container 16 is mounted so that a slight clearance is formed between the opening 16a of the container 16 and the exposed surface 7a of the drum cathode body 7, a part of the supplied electrolytic treatment liquid is removed from the clearance. The exposed surface 7a of the drum cathode body 7 flows out, and in the process, an exposed surface 7a of the drum cathode body exposed in the opening 16a is formed with a liquid film of the electrolytic treatment liquid having a uniform thickness. This is preferable since the conditions for forming the oxide film are stabilized.

By the way, as the electrolytic treatment solution to be supplied into the container 16, the electrolytic solution used for producing the metal foil layer is usually pumped up and used as it is. 6 and FIG. 7, which is a cross-sectional view taken along the line VII-VII of FIG. 6, show a state in which another device A ₃ is mounted on the exposed surface of the drum cathode body. In this device A ₃ , the electrolytic treatment solution holding means is a trough-shaped container 19. This gutter-shaped container 19
Both ends 19a, 19a in the longitudinal direction are opened at the top.
Are sealed. An electrolytic treatment liquid supply pipe 20 is attached to one end 19a to serve as an electrolytic treatment liquid supply means. One side 19b of the trough-shaped container 19 is connected to the other side 19c.
Its height is lower than.

The width of this trough-shaped container 19 is equal to that of the device A ₁
For the same reason as in the case of the electrolytic solution holding means 15, the width of the drum cathode body 7 is narrower than that of the drum cathode body 7, and both side portions 7b and 7b of the exposed surface 7a of the drum cathode body 7 are prevented from being electrolytically oxidized. There is. The trough-shaped container 19 has its longitudinal direction aligned with the width direction of the drum cathode body 7, and one side 19b thereof is the exposed surface 7a of the drum cathode body 7.
They are mounted in close proximity so that a slight clearance is formed between them.

On the other side 19d of the trough-shaped container 19, a counter electrode 17 is provided.
And a metal powder removing filter 21 is interposed between the counter electrode body 17 and the exposed surface 7a of the drum cathode body. As a result, the inside of the trough-shaped container 19 is
Is divided into a space 19d in which is arranged and a space 19e located on the exposed surface 7a side of the drum cathode body. In the metal powder removing filter 20 described above, the metal contained in the electrolytic treatment liquid used is electrolytically deposited on the surface of the counter electrode 17 during the electrolytic treatment to cause abnormal deposition as metal powder, and the metal powder is subjected to the electrolytic treatment liquid. It is interposed in order to prevent separation from the counter electrode body due to the flow force of 1) and deposition on the exposed surface 7a of the drum cathode body 7.

The electrolytic treatment liquid supplied from the supply pipe 20 to the trough-shaped container 19 fills the trough-shaped container 19 and then the one side 19
It overflows from b and flows down along the exposed surface 7a of the drum cathode body rotating in the direction of arrow p. Therefore, in this process, the liquid film of the electrolytically treated liquid having a uniform thickness is continuously formed on the exposed surface 7a of the drum cathode body.

As the electrolytic treatment solution, the electrolytic solution used for producing the metal foil layer may be used as it is, but the gutter-shaped container 1
Electrolysis solution supply pipes connected to the spaces 19d and 19e formed inside 9 are separately provided, and the electrolysis solution used for manufacturing the metal foil layer is supplied from each supply pipe to the space 19d, for example. Further, an electrolytic solution having a different composition or an electrolytic solution containing no metal ion may be supplied to the space 19e.

The cross-sectional shape of the trough-shaped container 19 is shown in FIG.
It is not limited to a triangle as shown in FIG.
For example, it may be a polygon such as a quadrangle or a hexagon, or a semicircle. The point is that the electrolytic treatment liquid with which the container 19 is filled overflows from one side 19b thereof and a liquid film can be formed on the exposed surface 7a of the drum cathode body.

8 and FIG. 9, which is a sectional view taken along line IX-IX in FIG. 8, shows a state in which a further device A ₄ is mounted on the exposed surface of the drum cathode body. This device A
_{In 4} , the electrolytic treatment liquid holding means 22 is an elongated closed container having a convex lens cross section. That is, in this closed container 22, the mounting portion 22b of the counter electrode body 17 for electrolytic oxidation is liquid-tightly attached to the back of the curved curved plate 22a, and both end portions 22c and 22c in the longitudinal direction are sealed. An electrolytic treatment solution supply pipe 23 is attached to the central position, and the electrolytic solution jetting means 2 is provided at the tip of the curved plate 22a.
2e are formed, and the whole of them constitutes an electrolytic solution supplying means to the exposed surface 7a of the drum cathode body 7. The ejection means 22e may be, for example,
Examples thereof include a plurality of holes formed along the longitudinal direction of the curved plate 22a and slits formed in the longitudinal direction of the curved plate 22a with a predetermined width.

The length of the closed container 22 is the same as that of the device A.
_{For the} same reason as in the case of the electrolytic solution holding means 15 of _{No. 1} , the width is smaller than the width of the drum cathode body 7, and both side portions 7b, 7b of the exposed surface 7a of the drum cathode body 7 are prevented from being electrolytically oxidized. . The counter electrode body 17 is arranged in the mounting portion 22b, and the entire container has its longitudinal direction aligned with the width direction of the drum cathode body 7, and its curved plate 2
The jetting means 22d formed on 2a is arranged so as to face the exposed surface 7a of the drum cathode body 7 at a predetermined interval.

The electrolytically treated liquid, which is fed into the container 22 from the supply pipe 23 by pumping up or the like, is filled in the container 22 and then jetted from the jetting means 22d to rotate the drum cathode body 7 in the direction of arrow p. It hits the exposed surface 7a,
By flowing down along the exposed surface 7a, a liquid film having a uniform thickness is formed there. As the electrolytic treatment solution, the electrolytic solution used for producing the metal thin film may be used as it is, but if necessary, other electrolytic solution, for example, dilute sulfuric acid aqueous solution may be used.

While maintaining this state, the drum cathode body 7 is used as an anode and the counter electrode body 17 is used as a cathode, and a predetermined voltage is applied between both electrodes to expose the exposed surface 7 of the drum cathode body.
a is electrolytically oxidized. Since the drum cathode body 7 is rotating in the direction of arrow p in the figure, an oxide film is formed on its exposed surface 7a continuously or intermittently. In addition,
In this device A ₄ , the surface facing the exposed surface 7a of the drum cathode body is formed into a curved surface, but the shape is not limited to this, and the electrolytic treatment liquid filled inside may expose the exposed surface of the drum cathode body. Any shape is acceptable as long as it can be ejected toward 7a. Further, inside the container 22, a means for uniformly dispersing the electrolytic treatment liquid, for example, a uniform small hole is bored in a pipe, and the electrolytic treatment liquid is supplied to the pipe and ejected from the small hole. Any means may be provided. Furthermore, the position where the supply pipe 23 is attached does not have to be the central position of the apparatus A ₄ , and may be any position as long as the electrolytic treatment liquid can be uniformly ejected from the ejection means 22d.

Further, a metal powder removing filter similar to that in the case of the device A ₃ is provided between the counter electrode 17 and the jetting means 22d, and the metal powder electrodeposited on the counter electrode is exposed on the exposed surface 7a of the drum cathode body 7. You may not let it flow into. This apparatus A ₄ reduces the usage amount of the electrolytic solution by making the jet outlet of the jetting means 22d as small as possible when the electrolytic solution for producing the metal foil layer having a relatively high metal concentration is used as the electrolytic treatment solution. Further, it is possible to reduce the scattering amount of the electrolytic solution, and to suppress the precipitation of the metal salt in the electrolytic processing solution used as much as possible.

For example, when an electrolytic copper foil using a copper sulfate electrolytic solution is manufactured, a copper sulfate solution having a relatively high copper concentration is used as the electrolytic solution. The electrolytic solution is used as an electrolytic treatment solution for forming an oxide film. When used, crystals of copper sulfate will form when the temperature becomes low, which will adhere to the equipment and electrolytic copper foil,
This may impede the smooth operation of the device. Therefore, in the apparatus A ₄ shown in FIGS. 7 and 8, the inconveniences described above can be easily eliminated only by changing the shape of the ejection means 22d and the distance to the exposed surface 7a of the drum cathode body.

[0063]

【Example】

Examples 1 and 2, Comparative Examples 1 and 2 1) Production of Current Collector Substrate In the apparatus shown in FIG. 2, the drum cathode body 7 was made of titanium, and the apparatus A ₄ shown in FIGS. I put it on.

An electrolytic solution 5 having a copper ion concentration of 100 g / liter, a sulfuric acid concentration of 100 g / liter and a bath temperature of 60 ° C. is supplied to the electrolytic cell 4, and the drum cathode body 7 and the anode body 6 are rotated while rotating the drum cathode body 7. Current density of 60A
/ Dm ² to energize to continuously form a copper foil layer on the surface of the drum cathode body 7 and peel it off to form an electrolytic copper foil 1
Was continuously produced.

While continuing the production of the electrolytic copper foil 1 described above,
The above-mentioned electrolytic solution is supplied from the supply pipe 23 of the apparatus A ₄ to the closed container 2
2 and is sprayed from the jetting means 22d onto the exposed surface 7a of the drum cathode body 7 rotating in the p direction, while maintaining a constant voltage of 50V between the drum cathode body 7 and the counter electrode body (made of titanium) 17. Hold on to voltage. A 70 nm-thick titanium oxide film was continuously formed on the exposed surface 7a of the drum cathode body 7.

Copper was electrodeposited on this titanium oxide film to form a copper foil layer, and the copper foil layer was continuously peeled off from the drum cathode body 7 to obtain an electrolytic copper foil 1. Then,
The obtained electrolytic copper foil 1 was roughened at a current density of 30 A / dm ² using an electrolytic solution having a copper ion concentration of 20 g / liter, a sulfuric acid concentration of 40 g / liter and a bath temperature of 30 ° C.

The electrolytic copper foil after the surface roughening treatment had an average thickness of 50 μm, and the surface roughness (Rz) of the surface separated from the drum cathode body (hereinafter referred to as S surface) was 5 μm and the surface on the opposite side. The surface roughness (Rz) (hereinafter referred to as M-plane) is 11μ.
It was m. Further, in this electrolytic foil, communication holes communicating with each other in the thickness direction were recognized, the diameter thereof was 0.1 to 3 μm, and the distribution density thereof was 100 to 200 pieces / mm ² .

2) Manufacture of electrodes Ketjen Black EC (carbon black manufactured by Akzo)
KU, specific surface area 950m ²/ G, average particle size 0.03 μm) 1
10 parts by weight of polyvinylidene fluoride powder 10 parts by weight
Parts were mixed, and N-methylpyrrolidone was added to the obtained mixed powder.
Pace of active material mixture (electrode mixture) by adding 2 parts by weight
Was prepared.

This paste was applied to both sides of the above-mentioned electrolytic copper foil, dried, and press-molded at a pressure of 2000 kg / cm ² to manufacture Example electrode 1 having a thickness of 100 μm, a width of 10 mm and a length of 20 mm. The amount of the active material mixture supported on this electrode was 20 mg. At the time of forming the oxide film, a constant voltage of 10 V is applied between the counter electrode body 17 and the drum cathode body 7,
Example Electrode 2 was produced in the same manner as Example Electrode 1 except that the electrolytic copper foil was produced while forming the titanium oxide film having a thickness of 14 nm on the exposed surface 7a of the drum cathode body 7.

The electrolytic copper foil used in the electrode 2 of this example had an average thickness of 50 μm, Rz of S plane was 2 μm, and Rz of M plane was Rz.
The diameter of the communication holes was 0.1 to 3 μm, and the distribution density was 20 to 40 holes / mm ² . For comparison, a rolled copper foil having a thickness of 50 μm was prepared, and 20 mg of the active material mixture was carried on both surfaces of the rolled copper foil in the same manner as described above, and Comparative Example Electrode 1
And

Further, both sides of the rolled copper foil were roughened with # 800 emery paper to have a surface roughness of about Rz 2 to 5 μm, and 20 mg of the active material mixture was carried thereon in the same manner as in the example to form a comparative electrode 2. did. 3) Silk life of electrode An electrolytic solution prepared by dissolving 1M of lithium perhydrochloride in 1 kg of propylene carbonate was prepared, and each of the above-mentioned electrodes was arranged as a negative electrode, and a metallic lithium foil was arranged as a counter electrode and a reference electrode. As a result, four types of 3-electrode cells were assembled.

Next, a constant current of 1.2 mA was applied to the 3-electrode cell to charge it to 0 V with respect to the reference electrode potential, the energization was stopped for 20 minutes, and a constant current of 1.2 mA was applied again. A charging / discharging cycle test was conducted in which a voltage was applied to the reference electrode to discharge it to 1.5 V. The 20th discharge capacity and the 1st discharge capacity of each 3-electrode cell in the above-mentioned charge / discharge cycle test were compared, and the ratio (%) of the former to the latter was calculated. The results are shown in Table 1.

[0073]

[Table 1] As is clear from the results of the display, the electrode of the example is less likely to cause a decrease in discharge capacity during the charge / discharge cycle, and has excellent cycle life characteristics.

This is because the current collector (electrolytic copper foil) has a porous structure of the above-mentioned specifications, so that the adhesion strength with the active material mixture carried on the current collector is high, and the charge / discharge cycle test process is performed. Therefore, the peeling of the active material mixture is effectively suppressed. Further, since the through holes of the three-dimensional network structure penetrate through the current collecting substrate in the thickness direction, lithium ions may pass through the through holes between the active material mixture carried on the surface. It is considered that this is because a uniform electron transfer reaction is progressing.

Example 3 The apparatus A ₃ shown in FIGS. 6 and 7 was mounted on the exposed surface of the titanium drum cathode body, and a constant voltage of 25 V was applied between the counter electrode body 17 and the drum cathode body 7. Then, an electrolytic copper foil is manufactured while forming a titanium oxide film having a thickness of 35 nm on the exposed surface 7a of the drum cathode body 7, and the electrolytic copper foil is subjected to a surface roughening treatment under the same conditions as in the case of the example electrode 1. went.

The obtained electrolytic copper foil had an average thickness of 25 μm,
Rz is 2 μm for S surface and Rz is 9 μm for M surface, the diameter of communication hole is 0.1 to 3 μm, and its distribution density is 150 to 250 pieces / mm.
It had a porous structure of ² . The electrolytic copper foils were brought into contact with each other at the S-sides and were stacked together to form a current collecting substrate having an average thickness of 50 μm with the M-side being the surface. Example electrode 3 was manufactured by supporting the material mixture.

The same charge / discharge cycle test as in the case of Example electrode 1 was conducted on this electrode. The discharge capacity of the 20th discharge with respect to the discharge capacity of the first discharge showed a value of 98% or more, and the electrode had excellent cycle life characteristics. Example 4 The apparatus A ₁ shown in FIG. 4 was mounted on the exposed surface of the titanium drum cathode body, and a constant voltage of 50 V was applied between the conductive roll 13 and the drum cathode body 7 to form a drum cathode body. An electrolytic copper foil was manufactured while forming a titanium oxide film having a thickness of 70 nm on the exposed surface 7 a of No. 7.

The obtained electrolytic copper foil had an average thickness of 20 μm,
Rz is 2 μm for S surface and Rz is 6 μm for M surface, the diameter of communication hole is 0.1 to 3 μm, and its distribution density is 350 to 450 pieces / mm.
It had a porous structure of ² . The active material mixture used in Example electrode 1 was supported on the M surface and the S surface of this electrolytic copper foil so that the ratio of the supported amount was 9: 1. Then, the S-sides were brought into contact with each other, two sheets were stacked, dried, and press-molded at a pressure of 2000 kg / cm ² to manufacture Example electrode 4.

The same charge / discharge cycle test as in the case of Example electrode 1 was conducted on this electrode. The discharge capacity of the 20th discharge with respect to the discharge capacity of the first discharge exhibited a value of 99% or more, and was excellent in cycle life characteristics. Example 5 Commercially available lithium carbonate (Li ₂ CO ₃ ) and basic cobalt carbonate (2CoCO ₃ .3Co (OH) ₂ ) were weighed so that the molar ratio of Li / CO was 1: 1 and the zirconia ball mill was used. After wet mixing using ethanol,
LiCoO _{2 is formed by} heat treatment at a temperature of 900 ° C. for 2 hours.
Was synthesized.

This was pulverized with the above ball mill to obtain a powder having an average particle size of 16 μm, and 100 parts by weight of this powder was mixed with 6 parts by weight of graphite powder having an average particle size of 0.1 μm. Furthermore, 3.5 parts by weight of polyvinylidene fluoride powder is added to N
-Methylpyrrolidone was dissolved in 30 parts by weight and added to the mixed powder of the LiCoO ₂ powder and the graphite powder described above to prepare a paste of the active material mixture (electrode mixture).

Using this paste, the electrodeposited copper foil shown in Example electrode 1 was used as a current collector substrate, and in the same manner as in Example electrode 1, the amount of active material mixture carried was 20 mg. Was manufactured. This electrode was subjected to the same charge / discharge cycle test as in the case of the example electrode. The discharge capacity of the 20th discharge with respect to the discharge capacity of the first discharge showed a value of 98% or more, and the electrode had excellent cycle life characteristics.

Example 6 In Example 1, the electrolytic solution was changed to a nickel sulfate concentration of 300.
g / liter, boric acid concentration 40 g / liter, bath temperature 60
Electrolyte solution for electrolytic nickel foil production at ℃
Using device A_Four50 on the exposed surface of the drum cathode body
70 nm thick titanium oxide film by the constant voltage method of V application
Current density 30A / dm while forming film ²With electrolytic nickel
Le foil was manufactured.

The obtained electrolytic nickel foil had an average thickness of 25 μm, Sz surface Rz of 2 μm, M surface Rz of 7 μm, a communication hole diameter of 0.1 to 4 μm, and a distribution density of 300 to
The number was 400 / mm ² , and the porosity was 5%, which was a porous structure. On the other hand, the composition is MmNi _3.55 Mn _0.4 Al _0.3 C
o _0.75 (Mm: misch metal), grain size 30-
Prepare 50 μm of hydrogen storage alloy powder, and use this alloy powder 1
A paste was prepared by mixing 5 parts by weight of a 60% dispersion of polytetrafluoroethylene powder and 30 parts by weight of a 1.2% carboxymethylcellulose aqueous solution with respect to 00 parts by weight.

This paste was applied to both sides of the above-mentioned two nickel foils, respectively, and the S-sides were brought into contact with each other to obtain 2
A negative electrode for a nickel-hydrogen battery having a thickness of 0.8 mm, a width of 70 mm, and a length of 100 mm was manufactured by stacking the sheets, drying, and press-molding at a pressure of 2000 kg / cm ² . On the other hand, thickness 0.8 mm,
The width is 70 mm and the length is 100 mm, and nickel hydroxide is used as the positive electrode active material, and its discharge capacity is about 0.
A publicly known positive electrode set to 7 times the value is prepared, and a 0.2 mm thick separator made of nylon is interposed between each of the four positive electrodes and the five negative electrodes, and the rating is made by using 6NKOH electrolyte. A nickel-hydrogen battery with a capacity of 10 Ah was assembled.

The battery was subjected to a charge-discharge cycle test in which 120% overcharge was carried out at 0.5 C and discharge up to a discharge end voltage of 1.0 V was carried out at 1.0 C as one cycle, and the discharge capacity at 500 cycles was lowered. The rate was measured. For comparison,
A negative electrode was manufactured by using a punching nickel sheet foil having an aperture ratio of 10% and a nickel foam having a porosity of 50% as a current collecting substrate, carrying a mixture under the same conditions as described above, and producing a negative electrode for each of Comparative Example electrode 3, As a comparative electrode 4, a nickel-hydrogen battery similar to that of the example was assembled. For these,
Simultaneously with the examples, the reduction rate of the discharge capacity after 500 cycles was measured. The above results are shown in Table 2.

The tensile strength and elongation of these current collecting substrates were measured according to the method specified in JIS C6511, and the results are also shown in Table 2. Further, the manufacturing cost of the comparative example electrode calculated when the manufacturing cost of the example electrode 6 is set to 1 is also shown in Table 2 as a relative value.

[0087]

[Table 2] As is clear from the results shown, when the electrode of the present invention is incorporated into a battery, the battery has a small discharge capacity reduction rate and excellent siruku life characteristics. Further, it has excellent mechanical characteristics as a current collector substrate, and even when it is wound and housed in a battery, an accident such as breakage does not occur. Since the current collecting substrate is manufactured by the electrolytic plating method, it can be mass-produced, the manufacturing cost thereof is reduced, and as a result, it contributes to the provision of inexpensive electrodes.

[0088]

As is apparent from the above description, claim 1
The electrode according to claim 2, wherein an oxide film having a thickness of 14 nm or more is formed on the exposed surface of the moving cathode body by the method of claim 2, and an electrolytic metal foil having a porous structure continuously produced on the oxide film is used as a current collector substrate. Therefore, the adhesion strength between the electrode mixture carried on the electrode and the current collecting substrate is increased, and the accident of peeling of the electrode mixture during the charge / discharge cycle is suppressed, and in the case of the electrode of the lithium battery, The electron transfer reaction during the operation of the battery smoothly proceeds through the communication hole of the current collecting substrate, so that the cycle life characteristic of the battery is improved.

Further, since the current collecting substrate can be continuously and mass-produced, the manufacturing cost thereof can be reduced and the electrode can be manufactured at a cost much lower than the conventional one.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an electrode of the present invention.

FIG. 2 is a schematic view showing an apparatus for producing an electrolytic metal foil.

FIG. 3 is a schematic view showing another manufacturing apparatus.

FIG. 4 is a partially cutaway perspective view showing a state in which an apparatus A ₁ used for forming an oxide film is mounted on an exposed surface of a drum cathode body.

FIG. 5 is a partially cutaway perspective view showing a state in which an apparatus A ₂ used for forming an oxide film is mounted on an exposed surface of a drum cathode body.

FIG. 6 is a partially cutaway perspective view showing a state in which an apparatus A ₃ used for forming an oxide film is mounted on an exposed surface of a drum cathode body.

7 is a cross-sectional view taken along the line VII-VII of FIG.

FIG. 8 is a partially cutaway perspective view showing a state in which an apparatus A ₄ used for forming an oxide film is mounted on an exposed surface of a drum cathode body.

FIG. 9 is a sectional view taken along line IX-IX in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Current collecting substrate (electrolytic metal foil) 1a, 1b Surface of current collector 1 2 Communication hole 2a Opening of communication hole 2 Active material mixture (mixture for electrodes) 4 Electrolyzer 5 Electrolyte 6 Anode body 7 Drum Cathode body (moving cathode body) 7'Belt cathode body (moving cathode body) 7a Drum cathode body 7 exposed surface 7'a Belt cathode body 7'exposed surface 7b Drum cathode body 7 both sides 8 Gap 9 Distributor 10a, 10b Roller 11 Electrolytic metal foil 12 Shaft 13 Conductive roll (counter electrode) 14 Electrolytic treatment liquid holding means 15 Electrolytic treatment liquid supply means 15a Electrolytic treatment liquid for forming oxide film 15b Opening 16 Container (electrolytic treatment liquid holding means) 16a Container 16 opening 16b side part of container 16 counter electrode 18 electrolytic treatment liquid supply means 18a electrolytic treatment liquid supply pipe 18b electrolytic treatment Liquid discharge pipe 19 Gutter-shaped container (electrolytically treated liquid holding means) 19a End part of gutter-shaped container 19b One side of gutter-shaped container 19 C Other side of gutter-shaped container 19 19d, 19e Space inside gutter-shaped container 19 20 Supply Pipe (Electrolytic Treatment Liquid Supply Means) 21 Metallic Powder Removal Filter 22 Sealed Container (Electrolytic Treatment Solution Holding Means) 22a Curved Plate 22b Counter Electrode Attachment Part 22c End of Sealed Container 22 22d Electrolytic Treatment Solution Ejection Means 23 Supply Pipe (electrolytic treatment liquid supply means)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koichi Ashizawa 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Tsukasa Akutsu 601-1 Ojizawa, Imaichi, Tochigi Prefecture Furukawa Circuit Foil Co., Ltd. Imaichi Plant

Claims (3)

[Claims] 1. An electrolysis solution is prepared by immersing an anode body and a moving cathode body in an electrolytic solution containing a metal ion, and conducting an electrolysis reaction by moving electricity between the anode body and the moving cathode body while moving the moving card body. A metal foil layer is continuously formed by electrodepositing a metal on the surface of the moving cathode body, and while moving the moving cathode body, the metal foil layer is continuously peeled off to continuously form an electrolytic metal foil. The method for producing, wherein the exposed surface of the moving cathode body exposed after peeling off the metal foil layer is electrolytically oxidized to form an oxide film having a thickness of at least 14 nm on the exposed surface. A method for producing a porous electrolytic metal foil, comprising forming the metal foil layer. 2. The method for producing a porous electrolytic metal foil according to claim 1, wherein the porous electrolytic metal foil is a current collecting substrate of an electrode for a secondary battery. 3. An electrode for a secondary battery, wherein a porous electrolytic metal foil having communication holes in the thickness direction is used as a current collecting substrate, and the current collecting substrate carries an electrode mixture.