JP2003109582A - Laminated strip material, laminated strip material for battery using the same, and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated strip material on which, a carbon containing film layer can be closely stuck within a practical range of industrial technology, and to provide a laminated strip material for a battery using the same and manufacturing method of the same. SOLUTION: For a laminated strips having a dry film layer on the surface of a foil, the dry film layer is a laminated strip material made of carbon and metal, and preferably, the dry film layer is a laminated strip material made of copper, iron, titanium, aluminum, gold, silver, nickel, or an alloy or a resin film thereof. A film layer containing carbon powder is formed on the dry film layer of the laminated strip material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated strip material suitable for an electrode material for a battery used as a cathode of a lithium ion secondary battery, a laminated strip material for a battery using the laminated strip material, and their production. Regarding the method.

[0002]

2. Description of the Related Art As a negative electrode material for a lithium ion secondary battery or the like, a copper foil having a coating layer containing carbon powder is used. However, since carbon has a low affinity with the metal surface, it may be exfoliated during handling or use, and the electrode performance may not be exhibited. Therefore, roughen the surface roughness of the copper foil,
Attempts have been made to improve the bonding force by the anchor effect, to heat in a special atmosphere to remove the rolling oil on the surface, and the like. Further, in JP-A-11-310864, along with forming an oxide film of copper on the surface of the copper foil, by appropriately adjusting the crystal orientation of the copper foil, the adhesion between the coating layer containing carbon powder and the copper foil Attempts to improve sex.

[0003]

However, in the above-described method of roughening the surface roughness, the bending strength decreases as the degree of roughening increases, and sufficient bonding strength is obtained only by removing the rolling oil on the surface. There is a problem such as not getting
The method of forming an oxide film increases electrical resistance, which may lead to a decrease in battery life and heat generation. An object of the present invention is to provide a laminated strip material to which a coating layer containing carbon can be adhered, a laminated strip material for a battery using the same, and a method for producing the laminated strip material, within the technically practically practical range. Is.

[0004]

The inventor of the present invention diligently studied a method for solving the above-mentioned drawbacks of the prior art. First,
The method of forming an oxide film increases electrical resistance and may lead to a decrease in battery life and heat generation. Therefore, this method was determined to be inappropriate as a battery material. Next, in a laminated material having a structure of a conventional foil material and a coating layer containing carbon,
As a result of examining various methods for improving the adhesion of the coating layer containing carbon on the foil material, the peeling of the coating layer containing carbon is caused by the weak affinity between the base foil material and carbon. Therefore, by forming a layer that improves the affinity between the foil material and the coating layer containing carbon,
The inventors have found that peeling of the coating layer from the foil material can be suppressed, and have reached the present invention.

That is, the present invention is a laminated strip having a dry film forming layer on the surface of a foil material, wherein the dry film forming layer is made of carbon and metal. Preferably, the foil material is copper, iron,
It is a laminated strip material which is titanium, aluminum, gold, silver, tin, nickel or their alloys or resin films. Further, the present invention is a laminated strip material for a battery, wherein a coating layer containing carbon powder is formed on the dry film-forming layer of the above-mentioned laminated strip material.

The present invention is also the above-mentioned method for producing a laminated strip material, wherein a dry film-forming layer made of carbon and metal is formed on at least one surface side of the foil material, preferably on both surfaces. It is a method for manufacturing a laminated strip material which is formed by deposition by a film forming method.
Preferably, the dry film-forming layer made of carbon and metal on one surface side is a method for manufacturing a laminated strip in which a metal layer is deposited and then a carbon layer is deposited. More preferably, the metal layer is copper, chromium, titanium, gold, silver, tin, aluminum,
Alternatively, it is a method for producing a laminated strip material which is an alloy thereof or a compound thereof. Still more preferably, the dry film forming method is a method for manufacturing a laminated strip material which is either or both of a physical vapor deposition method and a chemical vapor deposition method. The present invention also provides a method for producing a laminated strip material for a battery, which uses the laminated foil obtained by the method for producing a laminated strip material described above and forms a coating layer containing carbon powder on a dry film-forming layer of the laminated foil. Is.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An important feature of the present invention is to improve the adhesion between a foil material and a carbon-containing coating layer by forming a dry film-forming layer containing carbon on the surface of the foil material. is there.
The present invention will be described in detail below. In the present invention, the foil material,
A layer having a high affinity with the foil material is formed by a dry film forming method.
As the foil material used in the present invention, a foil material having a thickness and a length may be appropriately used depending on the application. For example, when the foil material is used as an electrode material of a secondary battery, it is processed by winding or the like to increase the electric capacity. Since it is enclosed in a case, a relatively long length is required, and a thinner thickness is advantageous because it reduces the size of the battery as a whole, so the length in the longitudinal direction is approximately 500 mm.
As described above, any strip material having a thickness of 50 μm or less may be used. in this case,
The material of the base foil material is inexpensive iron, an iron alloy that can impart various properties, copper or aluminum or aluminum alloy with excellent electrical conductivity, stainless steel with excellent chemical resistance,
Titanium, titanium alloys, gold, gold alloys, silver, silver alloys, tin, etc. are preferable, but as described later, by dry-forming these conductive metal layers on the surface, resin films and other A metal foil or the like can be used and may be selected depending on the application.

In the formation of the layer on the surface of the foil material by the dry film formation method, an arbitrary metal can be adhered and formed with a uniform thickness. In the case of the present invention, an element having a strong affinity with the foil material is previously formed into a film. Alternatively, carbon may be formed into a film, or an element having a strong affinity and carbon may be formed into a film at the same time, such as a so-called gradient structure, and the ratio thereof may be changed. When the metal is adhered and formed, the bonding force with the foil material can be increased. Examples of this element include chromium, copper, titanium, gold, tin, aluminum, nickel, germanium, or alloys thereof or compounds thereof, but it may be selected according to the material and application of the foil material. However, it is not particularly limited and may be, for example, a semimetal such as silicon. In the present invention, the aforementioned semimetal is also defined as a metal. The thickness of the dry film-forming layer is not particularly limited, but if the thickness is excessively thick, it is not economical and the dry film-forming layer may have a thickness that can achieve the purpose of improving the affinity with the foil material. For example, 10μ
The thickness may be less than m.

As the dry film forming method for forming the above-mentioned metals or alloys or compounds thereof, either physical vapor deposition method or chemical vapor deposition method may be used, and these may be combined. For this purpose, the sputtering method is the most preferable among the physical vapor deposition methods. This is because the chemical vapor deposition method raises the temperature of the material to be vapor-deposited, so that copper or a resin film that softens at a relatively low temperature cannot be used as a foil material. Further, since carbon has a high melting point and sublimes in a vacuum, it is difficult to control film formation by an EB melting type vacuum vapor deposition method or an ion plating method. Further, although a film called DLC (diamond like carbon) is formed by a physical vapor deposition method or a chemical vapor deposition method, such a film formation method may be used.

Using the above-mentioned laminated strip material having a dry film-forming layer formed on the foil material, a coating layer containing carbon is formed on the dry film-forming layer to obtain a laminated strip material for a battery. The coating layer containing carbon powder is a product obtained by adding fluorine-based resin such as PVDF as a binder to artificial or natural carbon powder, kneading these with an organic solvent, coating them on the surface of the foil material with a bar coater, and heating and drying. is there. Then, a dry film-forming layer containing carbon is formed between the film layer and the foil material to obtain a battery laminated strip material. The battery material of the present invention is suitable for use as a negative electrode material of a lithium-ion secondary battery, but it can also be used as a material in which carbon is adhered to a metal surface, such as a methanol reforming type fuel cell electrode material. Available.

[0011]

EXAMPLES The present invention will be described below based on examples.
As the foil material, JIS SUS304 having a thickness of 12 μm, an oxygen-free cylinder having a thickness of 10 μm, and tough pitch copper were prepared. The length is about 700 mm. No. 1, which is a foil strip material with a dry film-forming layer formed with carbon and chromium by sputtering to a thickness of 1 μm
No. 2, a metal layer of Cu was formed by a sputtering method, and then a dry film-forming layer having a thickness of 2 μm was formed by sputtering carbon and chromium, and a metal layer of Cu was formed by the sputtering method. No. 3 was obtained by forming a dry film formation layer of carbon to a thickness of 1 μm by the CVD method, and a laminated strip material having a dry film formation layer on the surface of the foil material was obtained.

On the dry film-forming layer of the laminated strip of the present invention,
It was decided to form a coating layer containing carbon. In either case, natural graphite (size 10 ~
40 μm) was mixed with a commercial PVDF resin in a weight ratio of 9: 1 and kneaded with alcohol as a solvent. Then, this was applied with a bar coater in an amount of 0.02 g / 1.69 cm ² (weight after drying) and dried at 110 ° C. for 5 minutes to obtain a laminated strip material for a battery. On the other hand, as a comparative example, the above-mentioned carbon-containing coating layer was formed on the surface of an oxygen-free copper foil material having a thickness of 10 μm to obtain a battery laminated strip material. As a result of winding this and visually confirming the presence or absence of peeling, peeling did not occur in the battery laminate of the present invention.

[0013]

The dry film-forming layer formed on the surface of the foil material can enhance the affinity with the foil material and improve the adhesion between the foil material and the coating layer containing carbon, and particularly the battery electrode material. Is effective in improving the performance of.

Continued front page    F-term (reference) 5H017 AA03 BB00 BB01 BB08 BB16                       CC01 DD00 EE01 EE04 EE05                       EE07                 5H018 AA07 AS07 BB07 CC06 DD08                       EE02 EE08 EE17                 5H050 AA07 AA08 BA17 CB07 DA04                       DA07 DA08 DA12 EA02 EA04                       EA08 FA02 FA18 GA24

Claims (8)

[Claims] 1. A laminated strip material having a dry film-forming layer on the surface of a foil material, wherein the dry film-forming layer comprises carbon and metal. 2. The laminated strip material according to claim 1, wherein the foil material is copper, iron, titanium, aluminum, gold, silver, tin, nickel, an alloy thereof, or a resin film. 3. A laminated strip material for a battery, wherein a coating layer containing carbon powder is formed on the dry film forming layer of the laminated strip material according to claim 1. 4. The method for manufacturing a laminated strip material according to claim 1, wherein a dry film forming layer made of carbon and metal is attached to at least one surface side surface of the foil material by a dry film forming method. A method for producing a laminated strip, which comprises forming the laminated strip. 5. The laminated strip according to claim 4, wherein the dry film-forming layer made of carbon and metal on one surface side is formed by depositing the metal layer and then depositing the carbon layer. Manufacturing method. 6. The metal layer comprises copper, chromium, titanium, gold, silver,
5. It is tin, aluminum, nickel, their alloys, or their compounds, It is characterized by the above-mentioned.
Alternatively, the method for producing a laminated strip according to item 5. 7. The dry film forming method is one or both of a physical vapor deposition method and a chemical vapor deposition method.
7. The method for producing a laminated strip according to any one of 6 to 6. 8. Using the laminated strip obtained by the method for producing a laminated strip according to claim 4, a coating layer containing carbon powder is formed on the dry film forming layer of the laminated foil. A method for producing a laminated strip material for a battery, which comprises forming the laminated strip material.