Laminate, method for producing same, and laminate-including conductor, current collector, battery, and vehicle

Abstract

This laminate comprises a resin layer that includes a conductive filler, and a metal layer that is provided on at least one surface of the resin layer, wherein the thickness of the metal layer is 0.01-2 μm and the average length RSm of roughness curve elements of the surface of the metal layer is 5-50 μm.

Description

Laminate and method for manufacturing the same, as well as conductors, current collectors, batteries, and vehicles containing the laminate.

[0001] The present invention relates to a laminate and a method for manufacturing the same, as well as a conductor, current collector, battery, and vehicle including the laminate.

[0002] While current collectors in batteries, such as lithium-ion batteries, primarily use metal current collectors, resin current collectors have recently been proposed from the standpoint of weight reduction and safety. Examples of resin current collectors include those containing resin and conductive fillers. Patent Document 1 discloses a resin current collector containing polypropylene resin and carbon nanotubes.

[0003] International Publication No. 2024 / 122311

[0004] The problem that this invention aims to solve is to provide a laminate that is useful as a resin current collector and has lower electrical resistance.

[0005] <1> A laminate comprising a resin layer containing a conductive filler and a metal layer provided on at least one surface of the resin layer, wherein the thickness of the metal layer is 0.01 μm or more and 2 μm or less, and the average length RSm of the surface roughness curve elements of the metal layer is 5 μm or more and 50 μm or less. <2> The laminate according to <1>, wherein the ten-point average roughness RzJIS of the surface of the metal layer is 0.001 μm or more and 0.5 μm or less. <3> The laminate according to <1> or <2>, wherein the arithmetic mean height Ra of the surface roughness curve of the metal layer is 0.0001 μm or more and 0.05 μm or less. <4> The volume resistivity of the laminate is 1.0 × 10 －８ Ω・cm or more 1.0×10 ０A laminate according to any one of <1> to <3>, wherein the density is Ω·cm or less. <5> A laminate according to any one of <1> to <4>, wherein the metal layer contains at least one metal selected from the group consisting of copper, aluminum, nickel, stainless steel and composites thereof. <6> A laminate according to any one of <1> to <5>, wherein the thickness of the resin layer is 1 μm or more and 100 μm or less. <7> A laminate according to any one of <1> to <6>, wherein the resin layer contains a thermoplastic resin. <8> A laminate according to <7>, wherein the thermoplastic resin contains at least one selected from the group consisting of polyolefin resins and polyphenylene ether resins. <9> A laminate according to any one of <1> to <8>, wherein the conductive filler contains at least one selected from the group consisting of carbon nanotubes, carbon fibers, carbon black and graphite. <10> A laminate according to any one of <1> to <9>, wherein the conductive filler contains at least one selected from the group consisting of carbon nanotubes and carbon fibers. <11> The laminate according to any one of <1> to <10>, wherein the content of the conductive filler in 100% by mass of the resin layer is 0.1% by mass or more and 50% by mass or less. <12> The laminate according to any one of <1> to <11>, wherein the ratio of the thickness of the resin layer to the thickness of the metal layer (thickness of the metal layer / thickness of the resin layer) is 0.0001 or more and 0.2 or less. <13> A method for manufacturing a laminate, comprising the step of providing a metal layer on at least one surface of a resin layer containing a conductive filler by at least one method selected from the group consisting of vapor deposition, sputtering, plating and lamination, wherein the thickness of the metal layer is 0.01 μm or more and 2 μm or less, and the average length RSm of the surface roughness curve elements of the metal layer is 5 μm or more and 50 μm or less. <14> A conductor comprising the laminate according to any one of <1> to <12>. A current collector comprising the laminate described in any one of <15>, <1>, to <12>. A battery comprising the laminate described in any one of <16>, <1>, to <12>. A vehicle equipped with the battery described in <17>, <16>.

[0006] The laminate of the present invention is useful as a resin current collector and has lower electrical resistance. It has a volume resistivity equivalent to that of metal, and since it uses less metal, it is superior in terms of weight reduction and safety, and can be suitably used in conductors, current collectors, batteries, vehicles, and the like.

[0007] The present invention will be described in detail below. However, the content of the present invention is not limited to the embodiments described below.

[0008] <Explanation of Terms> In this specification, when "X to Y" (where X and Y are any numbers) is used, unless otherwise specified, it includes the meaning of "greater than or equal to X and less than or equal to Y," as well as "preferably greater than X" and "preferably less than Y."

[0009] [Laminate] The laminate of the present invention comprises a resin layer containing a conductive filler and a metal layer provided on at least one surface of the resin layer.

[0010] <Resin Layer> The resin layer contains a conductive filler from the viewpoint of conductivity. Preferably, the resin layer is a layer made of a resin composition (A) containing a thermoplastic resin and a conductive filler.

[0011] (Conductive filler) The conductive filler is preferably at least one selected from the group consisting of carbon nanotubes, carbon fibers, carbon black, and graphite, more preferably at least one selected from the group consisting of carbon nanotubes and carbon fibers, and even more preferably carbon nanotubes.

[0012] The carbon nanotubes can be single-walled or multi-walled. Furthermore, the method for manufacturing the carbon nanotubes is not particularly limited; any method such as thermal decomposition (e.g., thermal CVD, plasma CVD), arc discharge, or laser evaporation may be used. In this embodiment, for example, carbon nanotubes described in Japanese Patent Application Publication No. 2018-127397 can be used.

[0013] On the other hand, specific examples of carbon black include Ketjenblack; acetylene black; furnace black; channel black; carbon black produced as a by-product when hydrocarbons such as naphtha are partially oxidized in the presence of hydrogen and oxygen to produce synthesis gas containing hydrogen and carbon monoxide, or carbon black obtained by oxidizing or reducing these by-products; acetylene black and Ketjenblack are preferred. These carbon blacks may be used individually or in combination of two or more types.

[0014] The carbon black is preferably in particulate form with an aspect ratio of 1 to 5. The aspect ratio, when the carbon black is in particulate form, refers to the value obtained by dividing the length of the major axis of the spherical components constituting the carbon black structure by the length of the minor axis of the spherical components. On the other hand, when the carbon black is in fibrous form, it refers to the value obtained by dividing the fiber length by the fiber diameter.

[0015] The average primary particle size of the carbon black is preferably 10 nm or more, and more preferably 20 nm or more. On the other hand, the upper limit is preferably 60 nm or less, and more preferably 50 nm or less. Furthermore, the average primary particle size of the carbon black is preferably 10 nm or more and 60 nm or less, and more preferably 20 nm or more and 50 nm or less. By setting the average primary particle size of the carbon black to 10 nm or more, the dispersibility in the resin composition (A) can be improved, and the formation of aggregates due to undispersed carbon black can be made less likely. On the other hand, by setting the average primary particle size of the carbon black to 60 nm or less, the volume resistivity, which is an indicator of conductivity when dispersed in the resin composition (A), can be reduced, and good conductivity can be obtained.

[0016] The DBP oil absorption rate of carbon black is preferably 50 ml / 100 g or more at the lower limit, and more preferably 100 ml / 100 g or more. On the other hand, the upper limit is preferably 750 ml / 100 g or less, and more preferably 400 ml / 100 g or less. Furthermore, the DBP oil absorption rate of carbon black is preferably 50 ml / 100 g or more and 750 ml / 100 g or less, and more preferably 100 ml / 100 g or more and 400 ml / 100 g or less. When the DBP oil absorption rate is 50 ml / 100 g or more, a large structure is formed, and good conductivity can be obtained. On the other hand, when the DBP oil absorption rate is 750 ml / 100 g or less, the dispersibility in the resin composition (A) is improved, and it is possible to make it difficult for aggregates to form due to undispersed carbon black. DBP absorption capacity refers to the degree of structure in which particles are aggregated by chemical or physical bonding, determined by the amount of Dibutyl phosphate (DBP) used to fill the voids between carbon black particles. It is the amount of DBP (ml) that can be contained per 100g of carbon black.

[0017] As carbon black, commercially available products such as "BLACK PEARLS," "VULCAN," and "STERLING" (manufactured by Cabot), "Ketjenblack EC" (manufactured by Lion Specialty Chemicals), "Denka Black" (manufactured by Denki Kagaku Kogyo), "Toka Black" (manufactured by Tokai Carbon), "Asahi Carbon Black" (manufactured by Asahi Carbon), and "Mitsubishi Carbon Black" (manufactured by Mitsubishi Chemical Corporation) can be used.

[0018] The content of conductive filler in 100% by mass of the resin layer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, from the viewpoint of the mechanical strength and conductivity of the laminate.

[0019] (Thermoplastic resin) The resin layer preferably contains a thermoplastic resin. From the viewpoint of ensuring the mechanical strength of the laminate, the thermoplastic resin preferably contains at least one selected from the group consisting of polyolefin resins and polyphenylene ether resins.

[0020] Examples of polyolefin resins include homopolymers of α-olefins having approximately 2 to 8 carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, and 1-hexene; copolymers of these α-olefins with other α-olefins having approximately 2 to 12 carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene, or vinyl compounds such as vinyl acetate, acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, styrene, and vinyl chloride; and graft polymers obtained by grafting the vinyl compounds onto the aforementioned α-olefin homopolymers or copolymers. Among these, from the viewpoint of stabilizing the interface between the resin layer and the metal layer to be formed, polypropylene resins or polyethylene resins are preferred, and polypropylene resins are more preferred. These polyolefin resins may be used individually or in combination of two or more types.

[0021] The polypropylene resin may be a propylene homopolymer (a homopolymer of propylene), or a copolymer of propylene and an olefin having 2 to 20 carbon atoms. One or more types of olefins may be copolymerized with propylene. Specific examples of propylene copolymers include propylene-ethylene copolymer, propylene-1-butene copolymer, and propylene-ethylene-1-butene copolymer. Among these, propylene homopolymer is preferred from the viewpoint of film-forming properties of the resin layer.

[0022] The polyethylene-based resin may be a polyethylene homopolymer (a homopolymer of ethylene), or may be copolymerized with a comonomer component such as an α-olefin or a vinyl monomer. Specific examples of the ethylene copolymer include ethylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, and the like.

[0023] The isotactic pentad fraction indicating the stereoregularity of the polypropylene-based resin is preferably 80 to 99%, more preferably 83 to 98%, and still more preferably 85 to 97%. If the isotactic pentad fraction is too low, the mechanical strength as a film may decrease. On the other hand, the upper limit of the isotactic pentad fraction is defined by the upper limit value industrially obtainable at present, but this may not be the case in the future when a resin with higher regularity is developed at the industrial level. The isotactic pentad fraction means a three-dimensional structure in which five methyl groups as side chains are all located in the same direction with respect to the main chain formed by carbon-carbon bonds composed of any five consecutive propylene units, or the ratio thereof. 13 It is determined from the pentad units in the polypropylene molecular chain measured by the signals in the methyl group region of the C-NMR spectrum. The assignment of the signals in the methyl group region conforms to A. Zambelli et al. (Macromol. 8, 687 (1975)). [[ID=X]] [[ID=Y]]

[0024] Also, the Mw / Mn, which is a parameter indicating the molecular weight distribution of the polypropylene-based resin, is preferably 1.5 or more, more preferably 2.0 or more. On the other hand, regarding the upper limit, it is preferably 10.0 or less, more preferably 8.0 or less, and still more preferably 6.0 or less. Further, the Mw / Mn is preferably 1.5 or more and 10.0 or less, more preferably 2.0 or more and 8.0 or less, and still more preferably 2.0 or more and 6.0 or less. The smaller the Mw / Mn, the narrower the molecular weight distribution, but by setting the Mw / Mn to 1.5 or more, sufficient extrusion moldability can be obtained, and industrial mass production is possible. On the other hand, by setting the Mw / Mn to 10.0 or less, the mechanical strength as a film can be ensured. Mw represents the weight average molecular weight, Mn represents the number average molecular weight, and Mw / Mn is obtained by the GPC (gel permeation chromatography) method.

[0025] The melt flow rate (MFR) of the polypropylene-based resin is preferably 1.0 to 30 g / 10 min, more preferably 5.0 to 20 g / 10 min. When the melt flow rate (MFR) is within the above range, even when the viscosity increases due to filling with a conductive filler, the resin composition (A) has sufficient melt viscosity during the molding process and can ensure the mechanical strength as a film. The melt flow rate (MFR) is a value measured under the conditions of a temperature of 230°C and a load of 2.16 kg in accordance with JIS K7210:2014.

[0026] As the polypropylene-based resin, for example, commercially available products such as the trade names "Novatec PP", "Wintec" (manufactured by Japan Polypropylene Corporation), "Notio", "Tafmer XR" (manufactured by Mitsui Chemicals, Inc.), "Zelas", "Thermolan" (manufactured by Mitsubishi Chemical Corporation), "Sumitomo Noblen", "Tafsellen" (manufactured by Sumitomo Chemical Company, Limited), "Prime PP", "Prime TPO" (manufactured by Prime Polymer Co., Ltd.), "Adflex", "Adsy l", "HMS-PP (PF814)" (manufactured by Sun Allomer Co., Ltd.), and "Versify", "Inspire" (manufactured by Dow Chemical Company) can be used.

[0027] From the viewpoint of the mechanical strength of the laminate, the content of thermoplastic resin in 100% by mass of the resin layer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and even more preferably 99% by mass or less. Furthermore, from the viewpoint of the mechanical strength of the laminate, the content of thermoplastic resin in 100% by mass of the resin layer is preferably 50% by mass or more and 99.9% by mass or less, more preferably 60% by mass or more and 99.5% by mass or less, and even more preferably 70% by mass or more and 99% by mass or less.

[0028] (Additives) The resin composition (A) may contain additives as needed, within a range that does not impair the effects of the present invention. Examples of additives include inorganic particles such as silica, talc, kaolin, and calcium carbonate; pigments such as titanium dioxide; flame retardants; weather stabilizers; heat stabilizers; antistatic agents; melt viscosity modifiers; crosslinking agents; lubricants; nucleating agents; plasticizers; anti-aging agents; antioxidants; light stabilizers; ultraviolet absorbers; neutralizing agents; anti-fogging agents; anti-blocking agents; slip agents; and colorants. When additives are used, their content is usually 30% by mass or less in the resin composition (A), preferably 0.0001 to 20% by mass, more preferably 0.001 to 15% by mass, and even more preferably 0.01 to 10% by mass.

[0029] (Thickness of the resin layer) The thickness of the resin layer is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 60 μm or less, from the viewpoint of weight reduction, thinning, and conductivity. Furthermore, the thickness of the resin layer is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 75 μm or less, and even more preferably 10 μm or more and 60 μm or less, from the viewpoint of weight reduction, thinning, and conductivity. The thickness of the resin layer is measured by the method described in the examples.

[0030] <Metal Layer> The laminate of the present invention includes a metal layer provided on at least one surface of the resin layer. This makes it possible to achieve low volume resistivity and surface resistivity equivalent to that of metal, while being a resin current collector that is lighter than metal current collectors.

[0031] From the viewpoint of conductivity and formability, the metal layer preferably contains at least one metal selected from the group consisting of copper, aluminum, nickel, stainless steel, and composites thereof, and more preferably contains at least one metal selected from the group consisting of copper and aluminum.

[0032] (Thickness of the metal layer) The thickness of the metal layer is 0.01 μm or more and 2 μm or less from the viewpoint of weight reduction, thinning, and conductivity. A metal layer thickness of 0.01 μm or more and 2 μm or less allows for the formation of a metal layer free from defects such as pinholes. From a similar viewpoint, the thickness of the metal layer is preferably 0.05 μm or more, more preferably 0.15 μm or more, and preferably 1.5 μm or less, and more preferably 1.2 μm or less. Also from a similar viewpoint, the thickness of the metal layer is preferably 0.05 μm or more and 1.5 μm or less, and more preferably 0.15 μm or more and 1.2 μm or less. The thickness of the metal layer is measured by the method described in the examples.

[0033] (Average length RSm of roughness curve elements) The average length RSm of the roughness curve elements on the surface of the metal layer is 5 μm or more and 50 μm or less, from the viewpoint of adhesion to the electrode and conductivity. By having an average length RSm of 5 μm or more and 50 μm or less on the surface roughness curve elements of the metal layer, appropriate irregularities can be provided to adhere to the electrode and improve conductivity. From a similar viewpoint, the average length RSm of the roughness curve elements on the surface of the metal layer is preferably 6 μm or more, more preferably 8 μm or more, and preferably 40 μm or less, more preferably 30 μm or less. From a similar viewpoint, the average length RSm of the roughness curve elements on the surface of the metal layer is preferably 6 μm or more and 40 μm or less, more preferably 8 μm or more and 30 μm or less. The average length RSm of the roughness curve elements on the surface of the metal layer can be measured in accordance with ISO 4287:1997. Specifically, it is measured by the method described in the examples.

[0034] (Ten-point average roughness RzJIS) The ten-point average roughness RzJIS of the surface of the metal layer is preferably 0.001 μm or more, more preferably 0.005 μm or more, even more preferably 0.01 μm or more, and preferably 0.5 μm or less, more preferably 0.3 μm or less, and even more preferably 0.1 μm or less, from the viewpoint of adhesion to the electrode and conductivity. Furthermore, the ten-point average roughness RzJIS of the surface of the metal layer is preferably 0.001 μm or more and 0.5 μm or less, more preferably 0.005 μm or more and 0.3 μm or less, and even more preferably 0.01 μm or more and 0.1 μm or less, as appropriate irregularities can provide adhesion to the electrode and improve conductivity. The ten-point average roughness RzJIS of the surface of the metal layer can be measured in accordance with JIS B 0601:2013. Specifically, it is measured by the method described in the examples.

[0035] (Arithmetic Mean Height Ra) The arithmetic mean height Ra of the surface roughness curve of the metal layer is preferably 0.0001 μm or more, more preferably 0.0005 μm or more, even more preferably 0.001 μm or more, and preferably 0.05 μm or less, more preferably 0.04 μm or less, and even more preferably 0.03 μm or less, from the viewpoint of adhesion to the electrode and conductivity. Furthermore, the arithmetic mean height Ra of the surface roughness curve of the metal layer is preferably 0.0001 μm or more and 0.05 μm or less, more preferably 0.0005 μm or more and 0.04 μm or less, and even more preferably 0.001 μm or more and 0.03 μm or less, since appropriate irregularities can provide adhesion to the electrode and improve conductivity. The arithmetic mean height Ra of the surface roughness curve of the metal layer can be measured in accordance with ISO 4287:1997. Specifically, it is measured by the method described in the examples.

[0036] (Volume resistivity) The volume resistivity of the metal layer is preferably 1.0 × 10 from the viewpoint of conductivity. －８ Ω·cm or more, more preferably 1.0 × 10 －７ Ω·cm or more, more preferably 1.0 × 10⁻⁶ －６ It is Ω·cm or greater, and preferably 1.0 × 10 ０ Ω·cm or less, more preferably 1.0 × 10 －２Less than Ω·cm, more preferably 1.0×10 －４ Less than Ω·cm. Also, from the perspective of conductivity, the volume resistivity of the metal layer is preferably 1.0×10 －８ Ω·cm or more and 1.0×10 ０ Less than Ω·cm, more preferably 1.0×10 －７ Ω·cm or more and 1.0×10 －２ Less than Ω·cm, more preferably 1.0×10 －６ Ω·cm or more and 1.0×10 －４ Less than Ω·cm. The volume resistivity of the metal layer can be measured in accordance with ASTM D991-89 (2020). Specifically, it is measured by the method described in the examples.

[0037] <Physical properties of the laminate> (Volume resistivity of the laminate) From the perspective of conductivity, the volume resistivity of the laminate of this embodiment is preferably 1.0× －８ Ω·cm or more, more preferably 1.0× －７ Ω·cm or more, even more preferably 1.0× －６ Ω·cm or more, and preferably 1.0× ０ Less than Ω·cm, more preferably 1.0× －２ Less than Ω·cm, even more preferably 5.0× －４ Less than Ω·cm, even more preferably 1.0× －４ Less than Ω·cm. Also, from the perspective of conductivity, the volume resistivity of the laminate of this embodiment is preferably 1.0× －８ Ω·cm or more and 1.0× ０ Less than Ω·cm, more preferably 1.0× －７ [[ID=​​​​​​​​​​​​(Surface resistivity of the laminate) The surface resistivity of the laminate in this embodiment is preferably 1.0 × 10 from the viewpoint of conductivity. －６ Ω / □ or greater, more preferably 1.0 × 10 －５ Ω / □ or greater, more preferably 1.0 × 10 －４ It is Ω / □ or greater, and preferably 1.0 × 10 ３ Ω / □ or less, more preferably 1.0 × 10 ２ Ω / □ or less, more preferably 1.0 × 10 １ It is less than or equal to Ω / □. Furthermore, the surface resistivity of the laminate in this embodiment is preferably 1.0 × 10 from the viewpoint of conductivity. －６ Ω / □ or more 1.0×10 ３ Ω / □ or less, more preferably 1.0 × 10 －５ Ω / □ or more 1.0×10 ２ Ω / □ or less, more preferably 1.0 × 10 －４ Ω / □ or more 1.0×10 １ The ratio is less than or equal to Ω / □. The surface resistivity of the laminate can be measured in accordance with ASTM D991-89 (2020). Specifically, it is measured by the method described in the examples.

[0039] <Thickness of the laminate> The thickness of the laminate in this embodiment is preferably 1 μm or more, more preferably 10 μm or more, even more preferably 20 μm or more, and preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 70 μm or less, from the viewpoint of weight reduction, thinning, and conductivity.

[0040] <Thickness of metal layer / Thickness of resin layer> In the laminate of this embodiment, the ratio of the thickness of the resin layer to the thickness of the metal layer (thickness of metal layer / thickness of resin layer) is preferably 0.0001 or more, more preferably 0.001 or more, even more preferably 0.005 or more, and preferably 0.2 or less, more preferably 0.15 or less, and even more preferably 0.1 or less, from the viewpoint of weight reduction, thinning, and conductivity.

[0041] <Layer structure of the laminate> The laminate of the present invention may have a metal layer on at least one surface of the resin layer. That is, the metal layer may be provided on one side of the resin layer, or the metal layer may be provided on both sides of the resin layer.

[0042] [Method for Manufacturing the Laminate] The laminate of this embodiment can be manufactured by a method comprising the step of providing a metal layer on at least one surface of a resin layer containing a conductive filler by at least one method selected from the group consisting of vapor deposition, sputtering, plating, and lamination. In this case, the thickness of the metal layer is 0.01 μm or more and 2 μm or less, and the average length RSm of the surface roughness curve elements of the metal layer is 5 μm or more and 50 μm or less. The preferred range for the thickness of the metal layer is the same as above, and the preferred range for the average length RSm of the surface roughness curve elements of the metal layer is also the same as above.

[0043] By using vapor deposition or sputtering methods and controlling the layering time and voltage, the thickness of the metal layer can be made thinner. Conversely, by using plating methods and controlling the layering time, the thickness of the metal layer can be made thicker.

[0044] By shortening the lamination time, the average length RSm of the surface roughness curve elements of the metal layer, the ten-point average roughness RzJIS of the metal layer's surface, and the arithmetic mean height Ra of the surface roughness curve of the metal layer can be made smaller. Conversely, by lengthening the lamination time, the average length RSm of the surface roughness curve elements of the metal layer, the ten-point average roughness RzJIS of the metal layer's surface, and the arithmetic mean height Ra of the surface roughness curve of the metal layer can be made larger.

[0045] Conventional known methods can be applied as vapor deposition, sputtering, plating, and lamination methods. For example, vapor deposition methods include physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD). Examples of physical vapor deposition methods include vacuum deposition and ion plating, while examples of chemical vapor deposition methods include plasma CVD using plasma and catalytic chemical vapor deposition (Cat-CVD) which uses a heated catalyst to catalytically decompose the material gas. Sputtering methods include two-electrode sputtering and magnetron sputtering. Plating methods include dry plating and wet plating. Wet plating is the most commonly used method and is broadly classified into displacement plating, electroplating, and electroless plating. Lamination methods include methods of lamination via an adhesive layer and methods of lamination via an adhesive layer. Among the vapor deposition method, sputtering method, plating method, and lamination method, vapor deposition, sputtering method, and plating method are preferred because they can efficiently produce laminates with low electrical resistance, vapor deposition and sputtering methods are more preferred, and vapor deposition is even more preferred.

[0046] [Applications of the Laminate] The laminate of this embodiment is useful as a resin current collector and has lower electrical resistance. It has a volume resistivity equivalent to that of metal, and since it uses less metal, it is superior in terms of weight reduction and safety, making it suitable for use as a conductor, current collector, battery, etc. Examples of battery applications include notebook computers, pen-input computers, mobile computers, e-book players, mobile phones, portable fax machines, portable copiers, portable printers, portable audio players, small video cameras, headphone stereos, video movies, LCD TVs, handheld vacuum cleaners, portable CDs, MiniDiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, mopeds, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, strobes, cameras, household backup power supplies, business backup power supplies, load leveling power supplies, and natural energy storage power supplies. It is particularly preferable to use it mounted in vehicles such as automobiles, motorcycles, mopeds, and bicycles.

[0047] The present invention will be described in more detail below with reference to examples, but the present invention is not to be construed as being limited thereto.

[0048] (Thickness of the metal layer) The thickness of the metal layer was measured using a microscope from the cross-section of the laminate or single layer obtained in the examples and comparative examples.

[0049] (Thickness of the resin layer) The thickness of the resin layer was measured using a microscope from the cross-section of the laminate or single layer obtained in the examples and comparative examples.

[0050] (Arithmetic mean height Ra of the surface roughness curve of the metal layer) The arithmetic mean height Ra of the surface roughness curve of the metal layer of the laminate or single-layer bodies obtained in the examples and comparative examples was measured using a surface roughness measuring instrument (model name "SURFTEST SJ-210", manufactured by Mitutoyo Corporation) in accordance with ISO 4287:1997. However, in Comparative Example 1, the arithmetic mean height Ra of the surface roughness curve of the resin layer was measured.

[0051] (Ten-point average surface roughness RzJIS of the metal layer) The ten-point average surface roughness RzJIS of the metal layer of the laminates or single layers obtained in the examples and comparative examples was measured using a surface roughness measuring instrument (model name "SURFTEST SJ-210", manufactured by Mitutoyo Corporation) in accordance with JIS B 0601:2013. However, in Comparative Example 1, the ten-point average surface roughness RzJIS of the resin layer was measured.

[0052] (Average length RSm of surface roughness curve elements of the metal layer) The average length RSm of the surface roughness curve elements of the metal layer of the laminate or single-layer metal layers obtained in the Examples and Comparative Examples was measured using a surface roughness measuring instrument (model name "SURFTEST SJ-210", manufactured by Mitutoyo Corporation) in accordance with ISO 4287:1997. However, in Comparative Example 1, the average length RSm of the roughness curve elements of the resin layer was measured.

[0053] (Volume resistivity of laminates or single layers) The volume resistivity of the laminates or single layers obtained in the examples and comparative examples was measured using a resistivity meter (model name "Lorestar-AP", manufactured by Mitsubishi Chemical Corporation) in accordance with ASTM D991-89 (2020).

[0054] (Surface resistivity of laminates or single layers) The surface resistivity of the laminates or single layers obtained in the examples and comparative examples was measured using a resistivity meter (model name "Lorestar-AP", manufactured by Mitsubishi Chemical Corporation) in accordance with ASTM D991-89 (2020).

[0055] Example 1 A laminate was obtained by sputtering a 0.2 μm thick layer of copper onto the surface of a 50 μm thick resin layer containing 96% by mass of polypropylene resin and 4% by mass of carbon nanotubes. Specifically, the resin layer and copper target were placed in a sputtering deposition apparatus (model name "ES-350", manufactured by Eiko Engineering Co., Ltd.), and the deposition chamber was set to 2 × 10 －６ The system was evacuated to Pa, argon gas was introduced at 6.8 sccm, and the pressure was adjusted to 0.7 Pa. Then, 100 W of power was applied using a DC power supply, and copper was laminated to a thickness of 0.2 μm to obtain a laminate. "Sccm" is an abbreviation for Standard Cubic Centimeters per Minute, and represents cc / min (ml / min) at 0°C and atmospheric pressure.

[0056] Example 2 A laminate was obtained by sputtering a 0.2 μm thick layer of aluminum onto the surface of a 50 μm thick resin layer containing 96% by mass of polypropylene resin and 4% by mass of carbon nanotubes. Specifically, the resin layer and aluminum target were placed in a sputtering deposition apparatus (model name "ES-350", manufactured by Eiko Engineering Co., Ltd.), and the deposition chamber was set to 2 × 10 －６ The system was evacuated to Pa, argon gas was introduced at 6.8 sccm, and the pressure was adjusted to 0.7 Pa. Then, 100 W of power was applied using a DC power supply, and aluminum was laminated to a thickness of 0.2 μm to obtain a laminate.

[0057] Example 3 A laminate was obtained by depositing copper to a thickness of 1 μm on the surface of a 50 μm thick resin layer containing 96% by mass of polypropylene resin and 4% by mass of carbon nanotubes using a plating method (electroless plating). Specifically, using an electroless copper plating bath, copper was deposited on the surface of the resin layer at a processing temperature of 65°C for a processing time of 20 minutes, and the copper was deposited to a thickness of 1 μm to obtain a laminate.

[0058] Example 4 A laminate was obtained by depositing a 0.1 μm thick layer of aluminum onto the surface of a 50 μm thick resin layer containing 96% by mass of polypropylene resin and 4% by mass of carbon nanotubes using a vapor deposition method. Specifically, the resin layer and aluminum particles as the deposition raw material were placed in an electron beam deposition apparatus (model name "SEC-08T", manufactured by Showa Vacuum Co., Ltd.) and 3 × 10 －３ After exhausting to Pa, an electron beam was irradiated onto aluminum particles to deposit the evaporated aluminum, and the aluminum was stacked to a thickness of 0.1 μm to obtain a laminate.

[0059] Comparative Example 1: A resin monolayer with a thickness of 50 μm was used, containing 96% by mass of polypropylene resin and 4% by mass of carbon nanotubes.

[0060] Comparative Example 2: An electrolytic copper foil with a thickness of 12 μm was used.

[0061] Comparative Example 3: A rolled aluminum foil with a thickness of 15 μm was used.

[0062]

[0063] As can be seen from Table 1, the volume resistivity of the laminates obtained in Examples 1 to 4 was equivalent to that of the metals in Comparative Examples 2 to 3, and significantly lower than that of the resin single layer obtained in Comparative Example 1. Furthermore, the surface resistivity of the laminates obtained in Examples 1 to 4 was significantly lower than that of the resin single layer obtained in Comparative Example 1. The laminates obtained in Examples 1 to 4 have volume resistivity equivalent to that of metals, and are superior in terms of weight reduction and safety due to the small amount of metal used, making them suitable for use as current collectors in batteries.

Claims

1. A laminate comprising a resin layer containing a conductive filler and a metal layer provided on at least one surface of the resin layer, wherein the thickness of the metal layer is 0.01 μm or more and 2 μm or less, and the average length RSm of the surface roughness curve elements of the metal layer is 5 μm or more and 50 μm or less.

2. The laminate according to claim 1, wherein the ten-point average roughness RzJIS of the surface of the metal layer is 0.001 μm or more and 0.5 μm or less.

3. The laminate according to claim 1, wherein the arithmetic mean height Ra of the surface roughness curve of the metal layer is 0.0001 μm or more and 0.05 μm or less.

4. The volume resistivity of the laminate is 1.0 × 10⁻⁶. －８ Ω・cm or more 1.0×10 ０ The laminate according to claim 1, wherein the density is Ω·cm or less.

5. The laminate according to claim 1, wherein the metal layer comprises at least one metal selected from the group consisting of copper, aluminum, nickel, stainless steel, and composites thereof.

6. The laminate according to claim 1, wherein the thickness of the resin layer is 1 μm or more and 100 μm or less.

7. The laminate according to claim 1, wherein the resin layer comprises a thermoplastic resin.

8. The laminate according to claim 7, wherein the thermoplastic resin comprises at least one selected from the group consisting of polyolefin resins and polyphenylene ether resins.

9. The laminate according to claim 1, wherein the conductive filler comprises at least one selected from the group consisting of carbon nanotubes, carbon fibers, carbon black, and graphite.

10. The laminate according to claim 1, wherein the conductive filler comprises at least one selected from the group consisting of carbon nanotubes and carbon fibers.

11. The laminate according to claim 1, wherein the content of the conductive filler in 100% by mass of the resin layer is 0.1% by mass or more and 50% by mass or less.

12. The laminate according to claim 1, wherein the ratio of the thickness of the resin layer to the thickness of the metal layer (thickness of the metal layer / thickness of the resin layer) is 0.0001 or more and 0.2 or less.

13. A method for manufacturing a laminate, comprising the step of providing a metal layer on at least one surface of a resin layer containing a conductive filler by at least one method selected from the group consisting of vapor deposition, sputtering, plating, and lamination, wherein the thickness of the metal layer is 0.01 μm or more and 2 μm or less, and the average length RSm of the surface roughness curve elements of the metal layer is 5 μm or more and 50 μm or less.

14. A conductor comprising a laminate according to any one of claims 1 to 12.

15. A current collector comprising a laminate according to any one of claims 1 to 12.

16. A battery comprising a laminate according to any one of claims 1 to 12.

17. A vehicle equipped with the battery described in claim 16.

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