JP7193915B2 - Surface-treated copper foil and current collector, electrode and battery using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a surface-treated copper foil and current collectors, electrodes and batteries using the same.

Rolled copper foils and electrolytic copper foils are used as current collectors for positive electrodes or electrodes of batteries, particularly secondary batteries. Any copper foil is required to have high adhesion between the positive or negative electrode active material and the copper foil as a current collector. In order to improve adhesion, there is an example in which surface treatment is performed to form unevenness on the surface of a copper foil. For example, as disclosed in Patent Document 1, the copper foil surface is polished with emery paper to form irregularities, thereby aiming to improve adhesion.

Japanese Patent No. 3733067

However, as described in Patent Document 1, sufficient adhesion between the current collector copper foil and the active material is not obtained even if the unevenness is formed by simply polishing the copper foil with abrasive paper such as emery paper. The problem was that I didn't get it.

Further, when a copper foil is provided with a roughening treatment layer by roughening plating to form unevenness, there is a problem that many roughening particles fall off from the roughening particle layer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface-treated copper foil for a battery, in which roughened particles are less likely to come off and which can obtain good adhesion to an active material.

The present inventors have extensively studied the reason why sufficient adhesion was not obtained in the conventional technology, and found that the roughened particles formed on the copper foil surface by roughening treatment using a copper sulfate plating bath are enlarged. We found a problem of non-uniformity due to the accumulation of coarsened particles. That is, there has been a problem that sufficient adhesion between the current collector copper foil and the active material cannot be obtained because the roughening particles fall off as copper powder from the piled-up portions of the roughening particles. Therefore, the present inventors have found that by controlling the ten-point average roughness Rz of the surface treatment layer obtained by forming the primary particle layer and the secondary particle layer on the surface side of the copper foil, adhesion with the active material It was found that the properties were improved. The present invention has been completed based on the above findings.

That is, the present invention provides a copper foil and a surface-treated copper foil for batteries having a surface treatment layer on at least one surface side of the copper foil, wherein the surface treatment layer is a primary particle layer and a secondary particle layer. in this order from the surface side of the copper foil, and the surface treatment layer surface of the surface-treated copper foil for batteries is measured in accordance with JIS B0601 1994 using a laser microscope with a wavelength of 405 nm. The surface-treated copper foil for batteries has a thickness Rz of 1.8 μm or more.

Further, in one embodiment of the present invention, the surface treatment layer surface of the surface-treated copper foil for batteries is measured according to JIS B0601 1994 using a laser microscope with a wavelength of 405 nm, and the arithmetic mean roughness Ra is 0. 0.26 μm or more.

Also, in one embodiment of the present invention, the primary particle layer contains one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn.

In one embodiment of the present invention, the secondary particle layer contains one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn. .

In one embodiment of the present invention, the surface treatment layer contains 100 μg in total of one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn. /dm ² or more.

In one embodiment of the present invention, the surface treatment layer contains 10000 μg in total of one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn. /dm ² or less.

Further, in one embodiment of the present invention, the surface treatment layer contains Ni, and the Ni adhesion amount is 100 μg/dm ² or more.

Further, in one embodiment of the present invention, the surface treatment layer contains Ni, and the Ni adhesion amount is 4500 μg/dm ² or less.

Further, in one embodiment of the present invention, the surface treatment layer contains Co, and the Co adhesion amount is 100 μg/dm ² or more.

Further, in one embodiment of the present invention, the surface treatment layer contains Co, and the Co adhesion amount is 6000 μg/dm ² or less.

Moreover, in one embodiment of the present invention, the primary particle layer is made of Cu.

Moreover, in one embodiment of the present invention, the secondary particle layer is made of Cu, Co, and Ni.

In one embodiment of the present invention, the copper foil is composed of In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg. 5 ppm by mass or more and 0.3 mass % or less in total of one or more selected from the group consisting of

In one embodiment of the present invention, the copper foil is composed of In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg. 5 ppm by mass or more and 300 ppm by mass or less in total of one or more selected from the group consisting of

In one embodiment of the present invention, the copper foil is composed of In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg. 301 ppm by mass or more and 0.3% by mass or less in total of one or more selected from the group consisting of

Further, in one embodiment of the present invention, the surface treatment layer further comprises a heat-resistant layer, an antirust layer, a chromate treatment layer, a silane coupling treatment layer, a plating layer, and a resin layer on the secondary particle layer. has one or more layers selected from

In one embodiment of the present invention, the surface-treated copper foil for batteries of the present invention is for secondary batteries.

Moreover, in one embodiment of the present invention, the surface-treated copper foil for a battery of the present invention is for a secondary battery current collector.

Further, the present invention is a current collector having the aforementioned surface-treated copper foil for batteries.

Further, the present invention is an electrode having the aforementioned surface-treated copper foil for batteries.

Further, the present invention is a battery having the aforementioned surface-treated copper foil for battery, current collector, or electrode.

According to the present invention, it is possible to obtain a surface-treated copper foil for a battery that has less falling off of roughening particles and has good adhesion to an active material. In addition, according to some embodiments of the present invention, it is possible to obtain a surface-treated copper foil for batteries having a surface treatment with even better heat resistance.

FIG. 2 is a conceptual diagram showing the state of roughening particles when a conventional roughening treatment is performed on the surface of a copper foil. FIG. 2 is a conceptual diagram showing the state of the surface treatment layer of the surface treated copper foil for batteries having the surface treatment layer of the present invention.

<Surface-treated copper foil for batteries>
The surface-treated copper foil for batteries (including copper alloy foil) of the present invention is used, for example, as a current collector for a battery or a secondary battery, and an active material thin film is formed thereon to form an electrode. can be used as an electrode (either positive electrode or negative electrode) or a secondary battery can be manufactured. The method for forming the active material thin film on the current collector is not particularly limited, but for example, a CVD method, a sputtering method, a vapor deposition method, a spraying method, a liquid containing an active material is applied on the current collector, and the A method of drying after that, a plating method, or the like can be mentioned. Among these thin film forming methods, the CVD method, the sputtering method, and the vapor deposition method are particularly preferably used. Alternatively, an intermediate layer may be formed on the current collector, and the active material thin film may be formed on this intermediate layer. The surface-treated copper foil for batteries of the present invention can be used for known electrodes, known current collectors, and known batteries. Examples of known batteries include lithium ion secondary batteries, all-solid secondary batteries, air batteries (lithium-air batteries, zinc-air batteries, etc.), sodium ion batteries, magnesium ion batteries, polyvalent ion batteries, and sulfur-based batteries for positive electrodes. Secondary batteries using substances, secondary batteries using organic substances exhibiting oxidation-reduction activity in the positive electrode, nickel-cadmium batteries, manganese batteries (dry batteries), alkaline batteries (dry batteries), lithium batteries (dry batteries), and the like. Examples of known electrodes and known current collectors include the electrodes and current collectors used in the above-described known batteries.

<Copper foil>
The form of the copper foil that can be used in the present invention is not particularly limited, and known copper foils can be used. Typically, the copper foil used in the present invention may be copper foil formed by dry plating or wet plating, electrolytic copper foil or rolled copper foil. Generally, electrolytic copper foil is produced by electrolytically depositing copper from a copper sulfate plating bath onto a titanium or stainless steel drum. Further, the rolled copper foil is manufactured by repeating plastic working and heat treatment using rolling rolls. Rolled copper foil is often used for applications that require flexibility. When using the above-mentioned copper foil, for example, a rolled copper foil, it is also possible to use a copper foil that has been subjected to an annealing treatment (annealing treatment) after the production of the copper foil, such as after rolling. A rolled copper foil that has been annealed is preferable because it improves bending resistance and the like.
Copper foil materials include tough pitch copper (JIS H3100 alloy number C1100), oxygen-free copper (JIS H3100 alloy number C1020 or JIS H3510 alloy number C1011), phosphorous deoxidized copper (JIS H3100 alloy number C1201, C1220 or C1221), and electrolytic copper. In addition to high-purity copper such as, for example, Sn-containing copper, Ag-containing copper, In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, A copper alloy such as a copper alloy added with one or more selected from the group consisting of Ni, Si, Zr, B and/or Mg, etc., or a Corson copper alloy added with Ni, Si, etc. can also be used. Copper foils and copper alloy foils having known compositions can also be used. In this specification, when the term "copper foil" is used alone, it also includes copper alloy foil. In addition, as a copper foil material, In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg are added to the above-mentioned high-purity copper. 5 mass ppm or more, preferably 10 mass ppm or more, preferably 15 mass ppm or more, preferably 20 mass ppm or more, preferably 25 mass ppm or more, preferably 30 mass ppm or more in total of one or more selected from the group consisting of , preferably 35 mass ppm or more, preferably 40 mass ppm or more, preferably 45 mass ppm or more, preferably 50 mass ppm or more, preferably 301 mass ppm or more, preferably 310 mass ppm or more, preferably 350 mass ppm or more, It is also possible to use a copper alloy with addition of preferably 380 mass ppm or more, preferably 400 mass ppm or more, preferably 500 mass ppm or more. In addition, as a copper foil material, In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg are added to the above-mentioned high-purity copper. 50% by mass or less, preferably 40% by mass or less, preferably 30% by mass or less, preferably 20% by mass or less, preferably 10% by mass or less, preferably 5% by mass or less in total of one or more selected from the group consisting of , preferably 1% by mass or less, preferably 0.8% by mass or less, preferably 0.6% by mass or less, preferably 0.5% by mass or less, preferably 0.3% by mass or less, preferably 0.28% by mass % or less, preferably 0.25 mass % or less, preferably 0.23 mass % or less, preferably 0.20 mass % or less, preferably 0.17 mass % or less, preferably 0.15 mass % or less, preferably It is also possible to use a copper alloy added with 300 mass ppm or less. Selected from the group consisting of In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg added to the above high-purity copper When the total concentration of one or more elements is high (for example, 301 ppm by mass or more), the strength of the copper foil is increased, which is effective. In addition, the sum of one or more elements selected from the group consisting of In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg When the concentration of is low (for example, 300 mass ppm or less), it is effective because it is excellent in flexibility.

<Surface treatment layer>
The surface treatment layer has a primary particle layer and a secondary particle layer in this order from the copper foil side. Since the surface treatment layer has a primary particle layer and a secondary particle layer in this order from the copper foil side, powder dropping caused by falling off of roughening particles is reduced. In addition, the surface treatment layer has a primary particle layer and a secondary particle layer in this order from the copper foil side, so that the adhesion between the copper foil and the active material is improved. It is presumed that this is because the provision of the primary particle layer and the secondary particle layer makes the roughened particles less likely to break. Moreover, the surface treatment layer has a primary particle layer and a secondary particle layer in this order from the copper foil side, thereby improving the heat resistance of the copper foil. The primary particle layer and the secondary particle layer can be formed by electroplating layers. The secondary particles are characterized by one or more particles grown on the primary particles. Alternatively, the secondary particle layer is a normal plating layer grown on the primary particles. The secondary particles may have a dendritic shape. That is, when the term "secondary particle layer" is used in this specification, the normal plating layer such as covering plating is also included. In addition, the secondary particle layer may be a layer having one or more layers formed by roughening particles, or a layer having one or more normal plating layers. It may be a layer having one or more plating layers. The surface treatment layer may have one or more layers other than the primary particle layer and the secondary particle layer. In addition, normal plating means plating performed under conditions of a current density equal to or lower than the critical current density.
In addition, the primary particle layer is roughened particles formed directly on the copper foil and roughened particles stacked on the roughened particles, and is formed directly on the copper foil. The layer contains roughening particles having the same composition as the roughening particles or having the same elements as the elements contained in the roughening particles formed directly on the copper foil. The secondary particle layer is roughened particles formed on the roughened particles contained in the primary particle layer, and has a different composition from the roughened particles forming the primary particle layer, or the primary particles The layer contains roughening particles containing an element not contained in the roughening particles forming the layer.
In addition, when the presence or absence of the elements constituting the primary particles and/or secondary particles and/or the concentration or adhesion amount of the elements cannot be measured, the primary particles and secondary particles are scanned, for example. When observed with a type electron micrograph, the particles that appear to overlap and exist on the copper foil side (below) and the particles that do not overlap are primary particles, and the particles that appear to overlap and are other particles. Particles existing above can be determined to be secondary particles. In addition, when a base plating layer (normal plating layer) such as copper is provided on the copper foil, the above-mentioned "roughened particles directly formed on the copper foil" are the base plating layer It also includes roughening particles formed directly on the .

The surface-treated copper foil for batteries of the present invention has a ten-point average roughness Rz of 1.8 μm or more when the surface of the surface-treated layer is measured using a laser microscope at a wavelength of 405 nm according to JIS B0601 1994. If Rz is less than 1.8 μm, as shown in the conceptual diagram of FIG. Since it is easily broken or comes off from the root, the adhesion to the active material is not good. On the other hand, when Rz is 1.8 μm or more, as shown in the conceptual diagram of FIG. 2, sharp rises are eliminated and rounded particles grow, so that branches are less likely to break and fall off from the roots. As a result, the adhesion with the active material is improved. From this viewpoint, the ten-point average roughness Rz is more preferably 1.9 μm or more, more preferably 2.0 μm or more, still more preferably 2.1 μm or more, still more preferably 2.2 μm or more, still more preferably 2.3 μm or more, and even more preferably 2.35 μm or more. The upper limit of the ten-point average roughness Rz is not particularly limited, but is typically 10 μm or less, preferably 8 μm or less, more preferably 5 μm or less, still more preferably 3.30 μm or less, still more preferably 3.20 μm. 3.10 μm or less, more preferably 3.05 μm or less, still more preferably 3 μm or less, still more preferably 2.95 μm or less, even more preferably 2.90 μm or less, still more preferably 2.85 μm or less, still more preferably 2.85 μm or less is 2.80 μm or less. It is presumed that when the Rz is small to some extent, such as 3 μm or less, the roughened particles are less likely to come off and the adhesion to the active material is better. In the case where the surface treatment layer is present on both surfaces of the copper foil, the effect of the present invention can be obtained if one ten-point average roughness Rz is within the above range. Both the ten-point average roughness Rz may be set within the above range.
In addition, the above-mentioned "surface treatment layer surface" refers to a plurality of surfaces such as a primary particle layer, a secondary particle layer, a heat-resistant layer, an antirust tank, a chromate treatment layer, a silane coupling treatment layer, and a plating layer. means the surface of the outermost layer of the plurality of layers.

Further, from the same viewpoint as described above, the surface-treated copper foil for batteries of the present invention has an arithmetic mean roughness Ra when the surface treatment layer surface is measured using a laser microscope with a wavelength of 405 nm in accordance with JIS B0601 1994. It is preferably 0.26 μm or more. The arithmetic mean roughness Ra is more preferably 0.28 μm or more, more preferably 0.30 μm or more, more preferably 0.32 μm or more, more preferably 0.34 μm or more, more preferably 0.36 μm or more, more preferably is greater than or equal to 0.38 μm, even more preferably greater than or equal to 0.40 μm. The upper limit of the arithmetic mean roughness Ra does not need to be particularly limited, but typically for example 5.0 μm or less, preferably 4.5 μm or less, more preferably 4.0 μm or less, more preferably 3.5 μm or less, and further Preferably 3.0 μm or less, more preferably 2.5 μm or less, still more preferably 2.0 μm or less, still more preferably 1.5 μm or less, still more preferably 1.0 μm or less, still more preferably 0.5 μm or less, still more preferably 0.5 μm or less It is 0.45 μm or less, more preferably 0.44 μm or less, still more preferably 0.41 μm or less, still more preferably 0.40 μm or less. In the case where the surface treatment layer is present on both surfaces of the copper foil, the effect of the present invention can be obtained as long as one arithmetic mean roughness Ra is within the above range. Both arithmetic mean roughnesses Ra may be set within the above range.

It is preferable that the average particle diameter of the primary particle layer is 0.1 to 0.6 μm. Also, the average particle diameter of the secondary particle layer is preferably 0.01 to 0.45 μm. Here, the particle size means the diameter of the smallest circle surrounding the grains when the roughened grains are photographed from directly above the copper foil with a scanning electron microscope and observed. Moreover, the average particle size means the arithmetic average value of the particle sizes of a plurality of roughening particles. Specifically, the average particle diameter of the primary particle layer is the arithmetic mean of the particle diameters of roughened particles of the primary particle layer existing in a region of 4 μm wide×3 μm long in the photograph taken with the scanning electron microscope. means value. In addition, the average particle size of the secondary particle layer is the arithmetic mean value of the particle sizes of the roughened particles of the secondary particle layer present in a region of 4 μm wide × 3 μm long in the photograph taken with the scanning electron microscope. means
In addition, when forming the primary particle layer, the average particle size of the primary particle layer is determined by reducing the concentration of elements that adhere to the copper foil by plating in the plating solution used and / or by increasing the current density. and/or by lengthening the surface treatment time (energization time during plating) and/or increasing the number of times of plating. In addition, when forming the primary particle layer, the average particle size of the primary particle layer is adjusted by increasing the concentration of elements that adhere to the copper foil by plating in the plating solution used and / or by decreasing the current density. and/or by shortening the surface treatment time (energization time during plating) and/or by reducing the number of times of plating.
In addition, the average particle diameter of the secondary particle layer is determined by reducing the concentration of elements that adhere to the copper foil by plating in the plating solution used when forming the secondary particle layer, and / or by reducing the current density can be increased by increasing , and/or increasing the surface treatment time (energization time during plating), and/or increasing the number of times of plating. In addition, when forming the secondary particle layer, the average particle diameter of the secondary particle layer is determined by increasing the concentration of the element that adheres to the copper foil by plating in the plating solution used, and / or the current density can be reduced by lowering , and/or shortening the surface treatment time (energization time during plating), and/or reducing the number of times of plating.

In the surface-treated copper foil for batteries of the present invention, the primary particle layer in the surface treatment layer is one selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn. Or it can have two or more elements. The primary particle layer in the surface treatment layer preferably contains one or more elements selected from the group consisting of Cu, W, Ti, As, Cr and P. The primary particle layer in the surface treatment layer preferably contains one or more elements selected from the group consisting of Cu, W, As and P. This is because it becomes easier to prevent powder falling off. Also, the secondary particle layer may contain one or more elements selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn. can. and one or more elements selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn contained in the primary particle layer and the secondary particle layer The total adhesion amount can be, for example, 100 μg/dm ² or more. The upper limit of the total adhesion amount is also not particularly limited, but it can be, for example, 10000 μg/dm ² or less. Further, one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn contained in the primary particle layer and the secondary particle layer can be, for example, 100 μg/dm ² or more. The upper limit of the total adhesion amount is also not particularly limited, but it can be, for example, 10000 μg/dm ² or less.

From the viewpoint of improving the battery capacity, the electrode active material is being studied from a simple carbon-based active material to a silicon-based active material or a composite active material in which multiple kinds of materials are mixed. When using such a silicon-based active material, a polyimide-based binder may be used, and heating at 300° C. or higher is required for bonding. Therefore, if the adhesion to the active material is good, the object of the present invention can be achieved. Copper foil is more preferred. One or two or more elements are selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn to form a secondary particle layer according to the adhesion amount. By doing so, the above heat resistance can be improved.

The surface-treated layer of the surface-treated copper foil for batteries of the present invention may contain no Ni or may contain Ni. When the surface treatment layer contains Ni, the amount of Ni attached to the surface treatment layer is preferably 100 μg/dm ² or more. If the Ni adhesion amount is less than 100 μg/dm ² , a problem may arise in that the heat resistance is remarkably deteriorated. When the surface treatment layer contains Ni, the amount of Ni attached to the surface treatment layer is preferably 4500 μg/dm ² or less. If it exceeds 4500 μg/dm ² , the thickness of the Ni film increases, which may increase the electrical resistance value and deteriorate the electrical properties of the current collector copper foil. The Ni adhesion amount is more preferably 200 μg/dm ² or more, still more preferably 300 μg/dm ² or more, and even more preferably 400 μg/dm ² or more. In addition, the Ni adhesion amount is more preferably 4400 μg/dm ² or less, still more preferably 4300 μg/dm ² or less, even more preferably 4200 μg/dm ² or less, still more preferably 4100 μg/dm ² or less, and even more preferably 4100 μg/dm 2 or less. It is preferably 4000 μg/dm ² or less, still more preferably 3950 μg/dm ² or less. When the surface-treated layer contains Ni, the chemical resistance of the surface-treated copper foil may be improved as compared with the case where the surface-treated copper foil does not contain Ni.

The surface-treated layer of the surface-treated copper foil for batteries of the present invention may contain no Co, or may contain Co. When the surface treatment layer contains Co, the amount of Co attached to the surface treatment layer is preferably 100 μg/dm ² or more. If the Co adhesion amount is less than 100 μg/dm ² , a problem may arise that the heat resistance is remarkably deteriorated. Moreover, when the surface treatment layer contains Co, the amount of Co attached to the surface treatment layer is preferably 6000 μg/dm ² or less. If it exceeds 6000 μg/dm ² , the thickness of the Co film becomes thicker, and magnetism develops, which may lead to the problem of poor electrical properties as a copper foil for batteries, particularly as a copper foil for current collectors. The amount of Co attached is more preferably 200 μg/dm ² or more, more preferably 300 μg/dm ² or more, more preferably 400 μg/dm ² or more, more preferably 500 μg/dm ² or more, more preferably 600 μg/dm ² or more. Above, more preferably 700 μg/dm ² or more, more preferably 800 μg/dm ² or more, more preferably 900 μg/dm ² or more, more preferably 1000 μg/dm ² or more. Further, the Co adhesion amount is more preferably 5500 μg/dm ² or less, more preferably 5000 μg/dm ² or less, more preferably 4500 μg/dm ² or less, more preferably 4300 μg/dm ² or less, more preferably 4200 μg/dm 2 or less. dm ² or less, more preferably 4100 μg/dm ² or less, more preferably 4000 μg/dm ² or less, more preferably 3950 μg/dm ² or less. In addition, when the surface treatment layer contains Co, there may be an effect that the weather resistance of the surface-treated copper foil is improved as compared with the case where Co is not contained.

In addition, in the present invention, the adhesion amount of elements such as Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, Sn, and P in the surface treatment layer is specified. It defines the total amount of adhered elements present in the surface treatment layer including the secondary particle layer. In addition, when these surface treatment layers are present on both surfaces of the copper foil, it is a rule for the surface treatment layer on one surface, and the elements contained in the surface treatment layers formed on both surfaces (for example, Ni, etc.).

In the surface-treated layer of the surface-treated copper foil for batteries of the present invention, the attachment amount of elements such as Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, Sn, and P is within the above range. For example, the type and adhesion amount thereof can be changed as necessary, but from the viewpoint of further improving the adhesion to the active material thin film, the primary particle layer is preferably made of Cu. Here, "the primary particle layer consists of Cu" is a concept including "the primary particle layer contains only Cu" and "the primary particle layer contains only Cu and unavoidable impurities". Moreover, from the viewpoint of improving the heat resistance of the surface-treated copper foil, the secondary particle layer is preferably made of Cu, Co and Ni. Here, "the secondary particle layer consists of Cu, Co and Ni" means "the secondary particle layer contains only Cu, Co and Ni", and "the secondary particle layer contains Cu, Co and Ni and unavoidable impurities”.

The amount of the element contained in the surface treatment layer is determined by increasing the concentration of the element in the surface treatment solution used for forming the surface treatment layer, and/or when the surface treatment is plating. It can be increased by increasing the current density and/or increasing the surface treatment time (energization time during plating). In addition, the amount of the element contained in the surface treatment layer is reduced by lowering the concentration of the element in the surface treatment solution used for forming the surface treatment layer, and/or when the surface treatment is plating. , by lowering the current density and/or by shortening the surface treatment time (the current application time during plating).

<Conditions for Forming Primary Particle Layer and Secondary Particle Layer>
The surface-treated layer of the surface-treated copper foil for batteries of the present invention forms a primary particle layer and a secondary particle layer in order from the surface side of the copper foil. The primary particle layer and the secondary particle layer may be formed directly from the surface side of the copper foil, by forming the base plating layer on the surface side of the copper foil, and then forming the primary particle layer and the secondary particle layer in that order. may The base plating layer described above may be a Cu plating layer. The conditions for forming the primary particle layer and the secondary particle layer are shown below, but these are merely preferred examples. As long as the measured ten-point average roughness Rz is 1.8 μm or more, plating conditions other than those shown below are not barred.
In addition, the ten-point average roughness Rz when the surface treatment layer surface is measured using a laser microscope with a wavelength of 405 nm in accordance with JIS B0601 1994 is the primary particle layer and / or forms a secondary particle layer. At that time, in the plating solution to be used, the concentration of elements that adhere to the copper foil due to plating should be reduced, and/or the current density should be increased, and/or the surface treatment time (energization during plating time) and/or the number of times of plating can be increased. In addition, the ten-point average roughness Rz when the surface treatment layer surface is measured using a laser microscope with a wavelength of 405 nm in accordance with JIS B0601 1994 is the primary particle layer and / or the secondary particle layer. At that time, the concentration of elements that adhere to the copper foil by plating in the surface treatment solution to be used is increased, and / or the current density is lowered, and / or the surface treatment time (when plating It can be reduced by shortening the energization time).
In addition, the arithmetic mean roughness Ra when the surface treatment layer surface is measured using a laser microscope with a wavelength of 405 nm in accordance with JIS B0601 1994 is the primary particle layer and / or when forming the secondary particle layer. In the plating solution used, the concentration of elements that adhere to the copper foil due to plating should be reduced, and/or the current density should be increased, and/or the surface treatment time (energization time during plating ) can be lengthened. In addition, the arithmetic mean roughness Ra when the surface treatment layer surface is measured using a laser microscope with a wavelength of 405 nm in accordance with JIS B0601 1994 is the primary particle layer and / or when forming the secondary particle layer. In the plating solution used, the concentration of elements that adhere to the copper foil due to plating should be increased, and/or the current density should be decreased, and/or the surface treatment time (energization time during plating ) and/or the number of times of plating can be reduced.

-Primary particle layer When the treatment is performed with the primary particle plating solution (B) after treatment with the primary particle plating solution (A), the primary particle layer can be formed under the following conditions.
(Treatment with primary particle plating solution (A))
<Electrolyte composition>
Copper: 5-15g/L
Sulfuric acid: 70-80g/L
<Manufacturing conditions>
Current density: 40-60A/dm ²
Electrolyte temperature: 25-35°C
Electrolysis time: 0.5 to 1.6 seconds (treatment with primary particle plating solution (B))
<Electrolyte composition>
Copper: 20-50g/L
Sulfuric acid: 60-100g/L
<Manufacturing conditions>
Current density: 4-10A/dm ²
Electrolyte temperature: 35-55°C
Electrolysis time: 1.4 to 2.5 seconds

When the primary particle layer is formed only by the treatment with the primary particle plating solution (I), it is carried out under the conditions described in the following treatment 1 with the primary particle plating solution (I) or treatment 2 with the primary particle plating solution (I). It is possible.
(Treatment 1 with primary particle plating solution (I))
<Electrolyte Composition>
Copper: 10-45g/L
Cobalt: 5-30g/L
Nickel: 5-30g/L
pH: 2.8-3.2
<Manufacturing conditions>
Current density: 30-45A/dm ²
Electrolyte temperature: 30-40°C
Electrolysis time: 0.3 to 0.8 seconds

(Treatment 2 with primary particle plating solution (I))
<Electrolyte Composition>
Copper: 5-15g/L
Nickel: 3-30g/L
pH: 2.6-3.0
<Manufacturing conditions>
Current density: 50-70A/dm ²
Electrolyte temperature: 30-40°C
Electrolysis time: 0.3 to 0.9 seconds

-Secondary particle layer When forming a secondary particle layer, it is possible to carry out treatment with the following secondary particle plating solution (I) or secondary particle plating solution (II).
(Treatment with secondary particle plating solution (I))
<Electrolyte Composition>
Copper: 10-15g/L
Cobalt: 5-15g/L
Nickel: 5-15g/L
pH: 2.8-3.2
<Manufacturing conditions>
Current density: 20-40A/dm ²
Electrolyte temperature: 33-37°C
Electrolysis time: 0.5 to 1.0 seconds

(Treatment with secondary particle plating solution (II))
<Electrolyte Composition>
Copper: 5-12g/L
Nickel: 2-11g/L
pH: 2.8
<Manufacturing conditions>
Current density: 55-65A/dm ²
Electrolyte temperature: 35-40°C
Electrolysis time: 0.3 to 0.9 seconds

<Overlay plating>
Cover plating can be performed on the secondary particle layer. The effect of improving heat resistance can be expected by forming cover plating. Layers formed by overlay plating include, for example, Zn--Cr alloy layer, Ni--Mo alloy layer, Zn layer, Co--Mo alloy layer, Co--Ni alloy layer, Ni--W alloy layer, Ni--Zn alloy layer, Ni -P alloy layer, Ni-Fe alloy layer, Ni-Al alloy layer, Co-Zn alloy layer, Co-P alloy layer, Zn-Co alloy layer, Ni layer, Co layer, Cr layer, Al layer, Sn layer, Zn, Cr, Ni, Fe, Ta, Cu, Al, P, W, Mn, Sn, As, Ti, Mo and Co etc. such as Sn-Ni layer, Ni-Sn layer or Zn-Ni alloy layer A metal layer made of one element selected from the group consisting of, or from the group consisting of Zn, Cr, Ni, Fe, Ta, Cu, Al, P, W, Mn, Sn, As, Ti, Mo and Co An alloy layer containing two or more selected elements or an alloy layer composed of two or more elements selected from the group of elements described above may be used.
Cover plating can be carried out by performing treatment with the following covering plating solution or the like, or by combining these. Metal layers and/or alloy layers that cannot be provided by wet plating can be provided by dry plating methods such as sputtering, physical vapor deposition (PVD), and chemical vapor deposition (CVD).

・Treatment with cover plating solution (1) Zn-Cr
Liquid composition: Potassium dichromate 1-1 g /L, Zn 0.1-5 g/L
Liquid temperature: 40-60°C
pH: 0.5-10
Current density: 0.01-2.6 A/dm ²
Energization time: 0.05 to 30 seconds

・Treatment with cover plating solution (2) Ni-Mo
Liquid composition: nickel sulfate 270-280 g/L, nickel chloride 35-45 g/L, nickel acetate 10-20 g/L, sodium molybdate 1-60 g/L, trisodium citrate 10-50 g/L, sodium dodecyl sulfate 50 ~90ppm
Liquid temperature: 20-65°C
pH: 4-12
Current density: 0.5-5 A/dm ²
Energization time: 0.1 to 5 seconds

・Treatment with cover plating solution (3) Zn
Liquid composition: Zn1-15g/L
Liquid temperature: 25-50°C
pH: 2-6
Current density: 0.5-5 A/dm ²
Energization time: 0.01 to 0.3 seconds

・Treatment with cover plating solution (4) Co-Mo
Liquid composition: Co 1-20 g/L, sodium molybdate 1-60 g/L, sodium citrate 10-110 g/L
Liquid temperature: 25-50°C
pH: 5-7
Current density: 1-4 A/dm ²
Energization time: 0.1 to 5 seconds

・Treatment with covering plating solution (5) Co-Ni
Liquid composition: Co 1 to 20 g/L, Ni 1 to 20 g /L
Liquid temperature: 30-80°C
pH: 1.5-3.5
Current density: 1-20A/dm ²
Energization time: 0.1 to 4 seconds

・Treatment with covering plating solution (6) Zn-Ni
Liquid composition: Zn 1-30 g/L, Ni 1-30 g /L
Liquid temperature: 40-50°C
pH: 2-5
Current density: 0.5-5 A/dm ²
Energization time: 0.01 to 0.3 seconds

・Treatment with covering plating solution (7) Ni-W
Liquid composition: Ni1-30g/L, W1-300mg/L
Liquid temperature: 30-50°C
pH: 2-5
Current density: 0.1-5 A/dm ²
Energization time: 0.01 to 0.3 seconds

・Treatment with covering plating solution (8) Ni-P
Liquid composition: Ni1-30g/L, P1-10g/L
Liquid temperature: 30-50°C
pH: 2-5
Current density: 0.1-5 A/dm ²
Energization time: 0.01 to 0.3 seconds

<Other surface treatments>
In addition, the surface treatment layer of the surface-treated copper foil for batteries of the present invention comprises a heat-resistant layer, an antirust layer, a chromate treatment layer, a silane coupling treatment layer, and a plating layer on the secondary particle layer or the cover plating layer described above. , and resin layers. The heat-resistant layer, rust-proof layer, chromate-treated layer, silane-coupling-treated layer, plating layer, and resin layer described above may each form a plurality of layers (for example, two or more layers, three or more layers, etc.).

Known heat-resistant layers and rust-preventive layers can be used as the heat-resistant layer and the rust-preventive layer. For example, the heat-resistant and/or anticorrosive layer may be from the group nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements, iron, tantalum. It may be a layer containing one or more elements selected from nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements , iron, and tantalum. Also, the heat-resistant layer and/or the antirust layer may contain oxides, nitrides, and silicides containing the aforementioned elements. Also, the heat-resistant layer and/or the antirust layer may be a layer containing a nickel-zinc alloy. Also, the heat resistant layer and/or the antirust layer may be a nickel-zinc alloy layer. The nickel-zinc alloy layer may contain 50 wt % to 99 wt % of nickel and 50 wt % to 1 wt % of zinc, excluding inevitable impurities. The nickel-zinc alloy layer may have a total deposition amount of zinc and nickel of 5 to 1000 mg/m ² , preferably 10 to 500 mg/m ² , preferably 20 to 100 mg/m ² . Further, the ratio of the nickel deposition amount to the zinc deposition amount of the layer containing the nickel-zinc alloy or the nickel-zinc alloy layer (=the deposition amount of nickel/the deposition amount of zinc) is 1.5 to 10. is preferred. Further, the nickel-adhesion amount of the layer containing the nickel-zinc alloy or the nickel-zinc alloy layer is preferably 0.5 mg/m ² to 500 mg/m ² , more preferably 1 mg/m ² to 50 mg/m ² . It is more preferable to have When the heat-resistant layer and/or the anti-corrosion layer is a layer containing a nickel-zinc alloy, the interface between the copper foil and the resin substrate is corroded by the desmear liquid when the inner walls of through holes, via holes, etc. come into contact with the desmear liquid. This improves the adhesion between the copper foil and the resin substrate.

For example, the heat-resistant layer and/or the antirust layer may comprise a nickel or nickel alloy layer with a coating amount of 1 mg/m ² to 100 mg/m ² , preferably 5 mg/m ² to 50 mg/m ² and a nickel or nickel alloy layer with a coating amount of 1 mg/m ² . up to 80 mg/m ² , preferably 5 mg/m ² to 40 mg/m ² , and a tin layer, and the nickel alloy layer is a nickel-molybdenum alloy, a nickel-zinc alloy, a nickel-molybdenum alloy. - Cobalt alloy or nickel-tin alloy may be used.

As used herein, the chromate-treated layer refers to a layer treated with a solution containing chromic anhydride, chromic acid, dichromic acid, chromate, or dichromate. The chromate treatment layer contains elements such as Co, Fe, Ni, Mo, Zn, Ta, Cu, Al, P, W, Sn, As and Ti (any form of metal, alloy, oxide, nitride, sulfide, etc.). may be included). Specific examples of the chromate-treated layer include a chromate-treated layer treated with an aqueous solution of chromic acid anhydride or potassium dichromate, and a chromate-treated layer treated with a treatment liquid containing chromic anhydride or potassium dichromate and zinc. .

The silane coupling treatment layer may be formed using a known silane coupling agent such as epoxy silane, amino silane, methacryloxy silane, mercapto silane, vinyl silane, imidazole silane, triazine silane. may be formed using a silane coupling agent such as Two or more kinds of such silane coupling agents may be mixed and used. Among them, it is preferably formed using an amino-based silane coupling agent or an epoxy-based silane coupling agent.

Further, on the surface of the copper foil, the surface treatment layer, the heat resistant layer, the rust prevention layer, the silane coupling treatment layer or the chromate treatment layer, for example, International Publication No. WO2006/028207, Patent No. 4828427, International Publication No. WO2006/134868, Patent No. 5046927, International Publication No. WO2007/105635, Patent No. 5180815, and the surface treatment described in JP-A-2013-19056 can be performed. can.

Hereinafter, description will be made based on examples and comparative examples. Note that this embodiment is merely an example, and is not limited to this example.
<Primary particle layer and secondary particle layer>
First, an ingot having the composition described in the column of "Composition of copper foil base material" in Table 1 was melted, and this ingot was hot-rolled from 900°C to obtain a plate with a thickness of 10 mm. Thereafter, cold rolling and annealing were repeated, and finally cold rolling to a copper foil with a thickness of 12 μm was obtained to obtain a rolled copper foil. As the electrolytic copper foil of Example 7, a 9 μm-thick HLP foil manufactured by JX Metals Co., Ltd. was prepared.
In Table 1, TPC in the "composition of copper foil base material" column means tough pitch copper (JIS H3100 alloy number C1100), and OFC means oxygen-free copper (JIS H3100 alloy number C1020). That is, for example, "190 ppm Ag-TPC" in Example 2 means that 190 ppm by mass of Ag was added to tough pitch copper. Also, for example, "1200 ppm Sn-OFC" in Example 4 means that 1200 ppm by mass of Sn was added to oxygen-free copper.
Subsequently, the surface of the rolled copper foil or the surface of the matte surface (deposition surface, M surface) of the electrolytic copper foil is subjected to electrolytic degreasing, washing with water, and pickling. A primary particle layer and/or a secondary particle layer were formed under the conditions shown in Table 1. In the examples and comparative examples in which "Primary particle layer plating current condition A" and "Primary particle layer plating current condition B" are described in Table 1, plating was performed under the conditions described in A, followed by the conditions described in B. It means that plating was further performed under the conditions specified. Plating solution conditions for forming the primary particle layer and the secondary particle layer are shown in the columns of "Primary particle layer plating solution A", "Primary particle layer plating solution B" and "Secondary particle layer plating solution" in Table 1 and below. . For example, when (1) is described in the column "Primary Particle Layer Plating Solution A", the primary It means that the particle layer A was formed.
(Plating solution conditions at the stage of primary particle layer A formation)
・Plating solution (1)
Liquid composition: 11 g/L of copper, 50 g/L of sulfuric acid
Liquid temperature: 25°C
pH: 1.0-2.0
・Plating solution (2)
Liquid composition: copper 11 g/L, tungsten 3 mg/L, sulfuric acid 50 g/L
Liquid temperature: 25°C
pH: 1.0-2.0
・Plating solution (3)
Liquid composition: copper 11 g/L, arsenic 100 mg/L, sulfuric acid 50 g/L
Liquid temperature: 25°C
pH: 1.0-2.0
・Plating solution (4)
Liquid composition: 11 g/L copper, 6 mg/L titanium, 50 g/L sulfuric acid
Liquid temperature: 25°C
pH: 1.0-2.0
・Plating solution (5)
Liquid composition: 11 g/L copper, 3 mg/L chromium, 50 g/L sulfuric acid
Liquid temperature: 25°C
pH: 1.0-2.0
(Plating solution conditions at the stage of primary particle layer B formation)
・Plating solution (1)
Liquid composition: 22 g/L of copper, 100 g/L of sulfuric acid
Liquid temperature: 50°C
pH: 1.0-2.0
(Plating conditions at secondary particle layer formation stage)
・Plating solution (1)
Liquid composition: 15 g/L copper, 8 g/L nickel, 8 g/L cobalt
Liquid temperature: 36°C
pH: 2.7
・Plating solution (2)
Liquid composition: Copper 15g/L, Nickel 8g/L, Phosphorus 1g/L
Liquid temperature: 36°C
pH: 2-3
・Plating solution (3)
Liquid composition: copper 15 g/L, nickel 8 g/L, cobalt 8 g/L, molybdenum 8 g/L
Liquid temperature: 36°C
pH: 2-3
・Plating solution (4)
Liquid composition: Copper 15g/L, Nickel 8g/L, Tungsten 3g/L
Liquid temperature: 36°C
pH: 2-3
・Plating solution (5)
Liquid composition: 15 g/L copper, 8 g/L molybdenum, 8 g/L cobalt
Liquid temperature: 36°C
pH: 2-3
<Overlay plating>
Subsequently, cover plating shown in Table 1 is formed on the primary particle layer in the case where only the primary particle layer is formed, and on the secondary particle layer in the case where the primary particle layer and the secondary particle layer are formed. did. Each specific condition is described below.
(1) Ni layer Plating solution composition: Ni 10g/L
pH: 2.5
Temperature: 50°C
Current density Dk: 12 A/dm ²
Plating time: 0.5 seconds Number of times of plating: 2 times (2) Ni—Co alloy layer Plating bath composition: Ni 10 g/L, Co 5 g/L
pH: 2.5
Temperature: 50°C
Current density Dk: 10 A/dm ²
Plating time: 0.5 seconds Number of times of plating: 2 times (3) Ni—Zn alloy layer Plating bath composition: Ni 10 g/L, Zn 5 g/L
pH: 3.5
Temperature: 40°C
Current density Dk: 2A/dm ²
Plating time: 1 second Plating times: 2 times <Electrolytic chromate treatment>
In Examples 1 to 7 and Comparative Examples 2 and 3, the following electrolytic chromate treatment was performed after forming the cover plating.
Liquid composition: potassium dichromate 3 g/L, Zn 0.5 g/L
Liquid temperature: 40-60°C
pH: 4.0
Current density Dk: 2.0 A/dm ²
Plating time: 0.6 seconds Number of times of plating: 2 times <Silane coupling treatment>
In Examples 1 to 7 and Comparative Examples 2 and 3, after performing electrolytic chromate treatment, the following silane coupling treatment was further performed.
Silane coupling agent: N-2-(aminoethyl)-3-aminopropyltrimethoxysilane Silane coupling agent concentration: 1.0vol%
Processing temperature: 25°C
Processing time: 3 seconds

In Comparative Example 4, as shown in Table 1, instead of forming the primary particle layer and the secondary particle layer under the above-described predetermined conditions, the surface was temper-rolled with a rolling roll having a roughened surface, and the surface was rolled in an air atmosphere. It was thermally oxidized and then heat-reduced in a nitrogen atmosphere containing 1% CO.
In Comparative Example 5, as shown in Table 1, instead of forming the primary particle layer and the secondary particle layer under the predetermined conditions, the first Cu plating, the second Cu plating and the third Cu plating were sequentially performed under the following conditions. gave.
(First Cu plating conditions)
Plating bath composition: Cu 150 g/L to 250 g/L, sulfuric acid 100 g/L
pH: 1.0
Temperature: 40°C
Current density Dk: 5 A/dm ²
Plating time: 7 seconds Number of times of plating: 1 time (second Cu plating condition)
Plating bath composition: Cu 50 g/L to 150 g/L, sulfuric acid 130 g/L
pH: 1.0
Temperature: 25°C
Current density Dk: 40 A/dm ²
Plating time: 7 seconds Number of times of plating: 1 time (3rd Cu plating condition)
Plating bath composition: Cu 150 g/L to 250 g/L, sulfuric acid 100 g/L
pH: 1.0
Temperature: 40°C
Current density Dk: 5 A/dm ²
Plating time: 7 seconds Plating times: 1 time (measurement of ten-point average roughness Rz)
The surface roughness Rz of the copper foil after the surface treatment in each experimental example was measured with a laser microscope OLS4000 manufactured by Olympus Corporation. Rz complies with JIS B0601 1994. Using a 50x objective lens, under the conditions of an evaluation length of 258 μm and a cutoff value of 0 in observing the surface of the copper foil, for rolled copper foil, measurement in the direction perpendicular to the rolling direction (TD), or electrolytic copper The foil was measured in the direction (TD) perpendicular to the advancing direction of the electrodeposited copper foil in the electrodeposited copper foil manufacturing apparatus, and 10 measurements were performed at different measurement positions, and the average value of the 10 measurements was obtained. The ambient temperature for measuring the surface roughness Rz with the laser microscope was 23 to 25.degree. The copper foil having the surface treatment layers on both sides had the same ten-point average roughness Rz on both sides.
(Measurement of arithmetic mean roughness Ra)
The surface roughness Ra of the copper foil after the surface treatment in each experimental example was measured with a laser microscope OLS4000 manufactured by Olympus. Ra complies with JIS B0601 1994. Using a 50x objective lens, under the conditions of an evaluation length of 258 μm and a cutoff value of 0 in observing the surface of the copper foil, for rolled copper foil, measurement in the direction perpendicular to the rolling direction (TD), or electrolytic copper The foil was measured in the direction (TD) perpendicular to the advancing direction of the electrodeposited copper foil in the electrodeposited copper foil manufacturing apparatus, and 10 measurements were performed at different measurement positions, and the average value of the 10 measurements was obtained. The ambient temperature for measuring the surface roughness Ra by the laser microscope was 23 to 25.degree. Regarding the copper foil having the surface treatment layers on both sides, both sides had the same arithmetic mean roughness Ra.
(Measurement of adhesion amount of Co, Ni and other elements)
The adhesion amount of Co, Ni and other elements was measured by ICP emission spectrometry after dissolving the surface treatment layer of the copper foil sample with a nitric acid aqueous solution having a concentration of 20% by mass. In the examples and comparative examples in which surface treatment layers were provided on both sides of the copper foil, one side was masked with an acid-resistant tape, etc., and the surface treatment layer on one side was dissolved to measure the amount of Co, Ni and other elements attached. did. After that, the above-mentioned masking is removed and the deposition amount of Co, Ni and other elements is measured on the other side, or another sample is used to measure the deposition of Co, Ni and other elements on the other side. amount was measured. Note that the values shown in Table 1 are the values for one side. As for the copper foil having the surface treatment layers on both sides, the amounts of Co, Ni and other elements adhered were the same on both sides. In addition, when Co, Ni and other elements do not dissolve in an aqueous nitric acid solution having a concentration of 20% by mass, after dissolving using a liquid capable of dissolving Co, Ni and other elements, the above-mentioned ICP issued analysis Measurement may be performed by As the liquid capable of dissolving Co, Ni and other elements, a known liquid, a known acidic liquid, or a known alkaline liquid may be used.
(Evaluation of particle shedding)
(1) Tape test A transparent mending tape is pasted on the surface-treated surface of the surface-treated copper foil, and when this tape is peeled off in a 180° direction, the falling particles adhering to the adhesive surface of the tape will Powder falling was evaluated from the appearance of discoloration. When the tape was not discolored, it was evaluated as "⊚"; when it turned gray, it was evaluated as "○";
(2) Conveyance Roll Confirmation In the production process of a secondary battery, a roll-to-roll conveyance line is used when coating an electrode active material on a copper foil for a current collector. Therefore, it is a problem that the roughening particles of the current collector copper foil surface treatment fall off from the rolls of the transfer line. Using the slit line device used to adjust the product width of copper foil for current collectors, the transport rolls are often cleaned once every several thousand meters of copper foil transport, but this roll contamination can reduce yield. evaluated. A state in which the roll was hardly soiled was rated as "⊚", a state in which sticking was slightly observed was rated as "∘", and a state in which the roll was markedly soiled was rated as "x".
(Evaluation of adhesion with active material)
Adhesion to the active material was evaluated by the following procedure.
(1) Artificial graphite with an average diameter of 9 μm and polyvinylidene fluoride are mixed at a weight ratio of 1:9 and dispersed in a solvent N-methyl-2-pyrrolidone.
(2) Apply the above active material to the surface of the copper foil.
(3) The copper foil coated with the active material is heated in a dryer at 90°C for 30 minutes. At this time, since the silane coupling agent does not have an OH group bonded to the copper surface, it hardly reacts with the copper surface due to the dehydration reaction with the unreacted silane coupling agent.
(4) After drying, cut into 20 mm squares and apply a load of 1.5 tons/mm ² ×20 seconds.
(5) The sample is cut in a grid pattern with a cutter, a commercially available adhesive tape (Sellotape (registered trademark)) is pasted, and a roller weighing 2 kg is placed and reciprocated once to press the adhesive tape.
(6) The adhesive tape is peeled off, and the active material remaining on the copper foil captures the image of the surface into a PC, and by binarization, the metallic luster part of the copper surface and the black part where the active material remains are distinguished, and the active material was calculated. The residual rate was the average value of three samples. The determination of the active material adhesion is as follows: residual rate of less than 50% "x", 50% to less than 70% "△", 70% to less than 80% "○", 80% to less than 90% "◎" , and 90% or more were evaluated as "◎◎".
(Heat resistance evaluation)
After cutting the surface-treated copper foil into a size of 20 cm × 20 cm, the copper foil cut sample was placed in an oven heated to 300 ° C. After 15 seconds, the copper foil sample was removed from the oven and the surface treatment was oxidized. The degree of discoloration was evaluated. "○" indicates that no oxidative discoloration occurred at all, "△" indicates that less than 30% of the 20 cm × 20 cm size has darkened oxidative discoloration, and "X" indicates that 30% or more of the 20 cm × 20 cm size has darkened oxidative discoloration. and

(Evaluation results)
All of Examples 1 to 14 had good particle dropout evaluation, good adhesion to the active material, and good heat resistance.
Since the secondary particle layer was not provided in Comparative Example 1, the ten-point average roughness Rz and the arithmetic average roughness Ra were out of the predetermined ranges, and thus the evaluation of particle drop-out and the adhesion were both unsatisfactory. Moreover, since no secondary particle layer was formed and no cover plating was provided, the heat resistance was also poor.
In Comparative Example 2, since the primary particle layer was not provided, the ten-point average roughness Rz was out of the predetermined range, and thus the evaluation of particle drop-out and the adhesion were both unsatisfactory.
In Comparative Example 3, a primary particle layer and a secondary particle layer were provided, but the ten-point average roughness Rz and the arithmetic average roughness Ra were out of the predetermined ranges, so the evaluation of adhesion remained at "Fair".
In Comparative Example 4, the ten-point average roughness Rz was within a predetermined range, but the adhesion was insufficient because the primary particle layer and the secondary particle layer could not be sequentially formed only by rolling. In addition, the heat resistance performance was poor because no covering plating layer was provided.
In Comparative Example 5, the ten-point average roughness Rz was within the predetermined range, but since the primary particle layer and the secondary particle layer could not be sequentially formed under such plating conditions, the results of the particle shedding test were not favorable and adhesion was poor. was inadequate.

Claims (21)

copper foil, and
Having a surface treatment layer on at least one surface side of the copper foil,
The surface treatment layer has a primary particle layer and a secondary particle layer,
The primary particle layer contains roughening particles,
The secondary particle layer contains roughened particles or a normal plating layer,
The surface of the surface treatment layer has a ten-point average roughness Rz of 1.8 μm or more when measured using a laser microscope with a wavelength of 405 nm in accordance with JIS B0601 1994.
Surface-treated copper foil for batteries. 2. The surface-treated copper foil for a battery according to claim 1, wherein the surface of said surface treatment layer has an arithmetic mean roughness Ra of 0.26 μm or more when measured using a laser microscope at a wavelength of 405 nm in accordance with JIS B0601 1994. . 3. The battery surface according to claim 1, wherein the primary particle layer contains one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn. Treated copper foil. 4. The secondary particle layer according to any one of claims 1 to 3, wherein the secondary particle layer contains one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn. The surface-treated copper foil for batteries according to . Claims 1 to 4, wherein the surface treatment layer contains one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn in a total amount of 100 µg/dm ² or more. The surface-treated copper foil for batteries according to any one of . Claims 1 to 5, wherein the surface treatment layer contains one or more selected from the group consisting of Cu, W, Ti, As, V, Mo, Ni, Co, Cr, Zn, P and Sn in a total amount of 10000 µg/dm ² or less. The surface-treated copper foil for batteries according to any one of . The surface-treated copper foil for a battery according to any one of claims 1 to 6, wherein the surface-treated layer contains Ni, and the amount of Ni adhered is 100 µg/dm ² or more. The surface-treated copper foil for batteries according to any one of claims 1 to 7, wherein the surface-treated layer contains Ni, and the amount of Ni adhered is 4500 µg/dm ² or less. The surface-treated copper foil for a battery according to any one of claims 1 to 8, wherein the surface-treated layer contains Co, and the amount of Co attached is 100 µg/dm ² or more. The surface-treated copper foil for a battery according to any one of claims 1 to 9, wherein the surface-treated layer contains Co, and the amount of Co attached is 6000 µg/dm ² or less. The surface-treated copper foil for batteries according to any one of claims 1 to 10, wherein the primary particle layer is made of Cu. The surface-treated copper foil for batteries according to any one of claims 1 to 11, wherein the secondary particle layer is composed of Cu, Co and Ni. The copper foil is selected from the group consisting of In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg. The surface-treated copper foil for batteries according to any one of claims 1 to 12, which contains 5 mass ppm or more and 0.3 mass% or less. The copper foil is selected from the group consisting of In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg. The surface-treated copper foil for batteries according to any one of claims 1 to 12, containing 5 mass ppm or more and 300 mass ppm or less. The copper foil is selected from the group consisting of In, Au, Pd, Ag, Cr, Fe, P, Ti, Sn, Zn, Mn, Mo, Co, Ni, Si, Zr, B and Mg. The surface-treated copper foil for batteries according to any one of claims 1 to 12, which contains 301 mass ppm or more and 0.3 mass% or less. The surface treatment layer further includes one or more layers selected from the group consisting of a heat-resistant layer, an antirust layer, a chromate treatment layer, a silane coupling treatment layer, a plating layer, and a resin layer on the secondary particle layer. The surface-treated copper foil for batteries according to any one of claims 1 to 15. The surface-treated copper foil for batteries according to any one of claims 1 to 16, which is for secondary batteries. The surface-treated copper foil for batteries according to any one of claims 1 to 17, which is used as a current collector for secondary batteries. A current collector comprising the surface-treated copper foil for batteries according to any one of claims 1 to 18. An electrode comprising the surface-treated copper foil for batteries according to any one of claims 1 to 18. A battery comprising the surface-treated copper foil for batteries according to any one of claims 1 to 18, the current collector according to claim 19, or the electrode according to claim 20.

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