Current collectors and batteries

Abstract

A current collector according to one embodiment of the present disclosure has a structure in which a first metal layer containing a first metal, a conductor layer containing a conductive carbon material, a second metal layer containing a second metal, and a third metal layer containing a third metal that is different from the first metal and the second metal are sequentially stacked in this order; and the third metal is nickel or copper.

Description

[Technical Field]

[0001] The present disclosure relates to a current collector and a battery using the same. [Background technology]

[0002] In recent years, research and development of secondary batteries containing solid electrolytes, such as all-solid-state batteries, has been actively conducted for applications such as portable devices, hybrid vehicles, electric vehicles, and home storage batteries. Such batteries are required to have even higher energy densities. Among these batteries, there are batteries that use a current collector based on a metal foil made of aluminum. Examples of batteries using current collectors include lithium secondary batteries that use a positive electrode plate in which a positive electrode layer containing a lithium compound is formed on such a metal foil.

[0003] Patent Document 1 discloses a current collector in which a metal layer and a non-metallic conductive layer are formed on an aluminum foil in order to improve corrosion resistance.

[0004] Patent Document 2 discloses a current collector that uses multiple conductive layers to improve capacitor characteristics.

[0005] Patent Document 3 discloses a structure in which a plurality of metal layers are laminated in order to improve adhesion to the positive electrode mixture.

[0006] Patent Document 4 discloses a current collector provided with a lithium barrier layer to improve safety. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-262866 [Patent Document 2] International Publication No. 2012 / 115050 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-4363 [Patent Document 4] Japanese Patent Application Publication No. 2017-10782 Summary of the Invention [Problem to be solved by the invention]

[0008] In the prior art, there is a demand for a battery that has a high energy density while suppressing a deterioration in battery characteristics. The present disclosure provides a current collector and a battery that can achieve both an improvement in battery energy density and suppression of a deterioration in battery characteristics. [Means for solving the problem]

[0009] A current collector according to one embodiment of the present disclosure has a structure in which a first metal layer containing a first metal, a conductor layer containing a conductive carbon material, a second metal layer containing a second metal, and a third metal layer containing a third metal different from the first metal and the second metal are stacked in this order, and the third metal is nickel or copper.

[0010] A battery according to one embodiment of the present disclosure includes the current collector, and at least one power generating element having a positive electrode layer, a negative electrode layer disposed opposite the positive electrode layer, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer, wherein the at least one power generating element includes a first power generating element stacked adjacent to the current collector, and the first metal layer of the current collector faces the positive electrode layer of the first power generating element without the solid electrolyte layer of the first power generating element and the conductor layer of the current collector interposed therebetween. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to improve the energy density of a battery while suppressing the deterioration of battery characteristics. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a current collector according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a schematic configuration of a battery according to the second embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing a schematic configuration of another battery according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] (Findings that led to one aspect of the present disclosure) Batteries containing solid electrolytes, such as all-solid-state batteries, generally comprise a power generating element having a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. While a battery can function as a battery by including at least one power generating element, stacking multiple power generating elements so that they are electrically connected in series can increase the battery's voltage. However, stacking multiple power generating elements, compared to a battery with a single power generating element, increases the contact resistance between the positive electrode layer and the negative electrode layer due to the current collectors, such as metal foils, provided on each of the power generating elements. This can lead to a decrease in battery performance due to the increased contact resistance between the positive electrode layer and the negative electrode layer. While increasing the confining pressure during charging and discharging can improve contact resistance, the tooling required to increase the confining pressure typically becomes larger, resulting in a decrease in the overall battery energy density. Furthermore, stacking two current collectors, one for the positive electrode layer and one for the negative electrode layer, between the power generating elements increases the battery's thickness and reduces its energy density.

[0014] Furthermore, by sharing either the current collector provided in the positive electrode layer or the current collector provided in the negative electrode layer between adjacent power generating elements, i.e., by disposing a single current collector between adjacent power generating elements, contact resistance can be eliminated and energy density can be improved. However, the current collector material can deteriorate due to lithium alloying and embrittlement at the operating potential of either the positive electrode layer or the negative electrode layer, and / or leaching into either the positive electrode layer or the negative electrode layer, resulting in a deterioration of battery performance. For example, aluminum is prone to deterioration when used as a current collector for the negative electrode layer, and nickel and copper are prone to deterioration when used as a current collector for the positive electrode layer. Furthermore, metals or alloys that are difficult to form lithium alloys or leach at the operating potentials of both the positive electrode layer and the negative electrode layer tend to have high electrical resistance, and using such metals or alloys as current collectors also reduces battery performance.

[0015] The present disclosure is based on this knowledge and suppresses the deterioration of battery characteristics by suppressing an increase in resistance between power generating elements and deterioration of the current collector, while achieving both an improvement in the energy density of the battery and suppression of the deterioration of battery characteristics by using a current collector that can be made thinner.

[0016] An outline of one aspect of the present disclosure is as follows.

[0017] A current collector according to one embodiment of the present disclosure has a structure in which a first metal layer containing a first metal, a conductor layer containing a conductive carbon material, a second metal layer containing a second metal, and a third metal layer containing a third metal different from the first metal and the second metal are stacked in this order, and the third metal is nickel or copper.

[0018] As a result, even when using the current collector according to this embodiment to electrically connect power generating elements in series by bonding a positive electrode layer to the first metal layer and bonding a negative electrode layer to the third metal layer, the current collector is less likely to deteriorate. Specifically, because the first metal layer contains a first metal different from the third metal, which is nickel or copper, it is less likely to deteriorate, such as by lithium alloying, even when bonded to a positive electrode layer. Furthermore, because the third metal layer contains the third metal, which is nickel or copper, it is less likely to deteriorate, such as by lithium alloying, even when bonded to a negative electrode layer. Furthermore, because the second metal layer and the third metal layer contain different metals, they are stacked, and by appropriately selecting the second metal and the third metal, both compatibility with the negative electrode layer and mechanical strength can be achieved. Furthermore, by positioning a conductive layer between the first metal layer and the second metal layer, the bonding strength between the first metal layer and the second metal layer is improved, making it less likely that battery performance will deteriorate. Furthermore, because the power generating elements can be electrically connected without placing two current collectors between them, the energy density of the battery can be increased. Therefore, the current collector according to this embodiment can improve the energy density of the battery while suppressing the deterioration of the battery characteristics.

[0019] Also, for example, the first metal may be aluminum or iron.

[0020] This makes it more difficult for the first metal layer to form an alloy with lithium and for lithium to be eluted into the positive electrode layer when the first metal layer is joined to the positive electrode layer, thereby suppressing deterioration of the battery characteristics.

[0021] Also, for example, the second metal may be titanium or chromium.

[0022] This makes it easier to form a second metal layer with high hardness, and prevents the negative electrode layer bonded to the third metal layer from coming into contact with the first metal layer due to pressure or the like during battery manufacturing.

[0023] Furthermore, for example, the second metal layer may be harder than the third metal layer.

[0024] This prevents the negative electrode layer bonded to the third metal layer from coming into contact with the first metal layer due to pressure or the like during battery manufacturing. Also, because the third metal layer 104 bonded to the negative electrode layer is softer, the contact resistance between the negative electrode layer and the third metal layer 104 is less likely to be high.

[0025] Furthermore, for example, the sum of the thickness of the second metal layer and the thickness of the third metal layer may be smaller than the thickness of the first metal layer.

[0026] This makes it possible to improve the energy density of a battery using the current collector.

[0027] Furthermore, for example, the thickness of the third metal layer may be greater than the thickness of the second metal layer.

[0028] This makes the third metal layer containing copper or nickel thicker, which makes it difficult for the electrical resistance of the current collector to increase, and can suppress deterioration in the battery characteristics of a battery using the current collector.

[0029] Furthermore, for example, the thickness of the first metal layer may be not less than 3 μm and not more than 50 μm.

[0030] This makes it possible to improve both the mechanical strength of the current collector and the energy density of a battery using the current collector.

[0031] Furthermore, for example, the thickness of the second metal layer may be 0.1 μm or more and 0.5 μm or less.

[0032] This makes it difficult for the second metal layer to peel off, and also prevents the negative electrode layer bonded to the third metal layer from coming into contact with the first metal layer due to pressure or the like during battery manufacturing.

[0033] Furthermore, for example, the thickness of the third metal layer may be not less than 0.5 μm and not more than 1.5 μm.

[0034] This makes it difficult for the third metal layer to peel off, and also prevents the negative electrode layer bonded to the third metal layer from coming into contact with the first metal layer due to pressure or the like during battery manufacturing.

[0035] Furthermore, for example, the thickness of the conductive layer may be 0.1 μm or more and 2.0 μm or less.

[0036] This makes it possible to improve both the bonding strength between the first metal layer and the second metal layer and the energy density of a battery using the current collector.

[0037] Furthermore, a battery according to one embodiment of the present disclosure includes the current collector, and at least one power generating element having a positive electrode layer, a negative electrode layer disposed opposite the positive electrode layer, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer, wherein the at least one power generating element includes a first power generating element stacked adjacent to the current collector, and the first metal layer of the current collector faces the positive electrode layer of the first power generating element without the solid electrolyte layer of the first power generating element and the conductor layer of the current collector interposed therebetween.

[0038] This allows for the realization of a battery in which the first metal layer of the current collector and the positive electrode layer of the first power generating element are electrically connected. Furthermore, the first metal layer is laminated with the positive electrode layer without any intervening layers, but because it contains a first metal different from the third metal, which is nickel or copper, it is less likely to deteriorate. This prevents the deterioration of battery characteristics of a battery using the current collector. Furthermore, the third metal layer on the opposite side of the current collector from the first metal layer contains the third metal, which is nickel or copper, and therefore is less likely to deteriorate even when joined to the negative electrode layer. Therefore, the battery according to this embodiment is less likely to deteriorate in battery characteristics even when joined to the negative electrode layer of a power generating element other than the first power generating element without another current collector sandwiched therebetween and electrically connected in series with the other power generating element. This allows for the reduction in the number of current collectors used and the increase in energy density.

[0039] Furthermore, for example, the at least one power generating element may further include a second power generating element stacked adjacent to the first power generating element with the current collector interposed therebetween, and the third metal layer of the current collector may face the negative electrode layer of the second power generating element without the solid electrolyte layer of the second power generating element and the second metal layer of the current collector interposed therebetween.

[0040] This electrically connects the third metal layer of the current collector to the negative electrode layer of the second power generating element, enabling a high-voltage battery in which the first power generating element and the second power generating element are electrically connected in series using a single current collector. This increases the energy density of the battery. Furthermore, although the third metal layer is laminated with the negative electrode layer without any other layers in between, it is less susceptible to degradation because it contains the third metal, which is nickel or copper. This prevents the battery's performance from deteriorating.

[0041] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0042] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step sequences shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not described in independent claims are described as optional components.

[0043] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0044] In this specification and drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional Cartesian coordinate system, with the z-axis coinciding with the stacking direction of the current collector and each layer of the battery.

[0045] In this specification, the "stacking direction" corresponds to the direction normal to the principal surface of each layer of the current collector and the battery. In addition, in this specification, the term "plan view" refers to the view from a direction perpendicular to the principal surface of the battery or the current collector, unless otherwise specified, such as when used alone.

[0046] Furthermore, in this specification, the terms "upper" and "lower" do not refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in a stacked configuration. Furthermore, the terms "upper" and "lower" are used not only when two components are arranged with a gap between them and another component is present between them, but also when two components are arranged closely together and are in contact with each other. In the following description, the negative side of the z axis is referred to as "lower" or "lower side," and the positive side of the z axis is referred to as "upper" or "upper side."

[0047] In this specification, percentages indicating the proportions of materials are by weight unless otherwise specified.

[0048] (Embodiment 1) In the first embodiment, a current collector having a laminated structure will be described.

[0049] [Collector composition] FIG. 1 is a cross-sectional view showing a schematic configuration of a current collector 100 according to this embodiment.

[0050] As shown in FIG. 1 , the current collector 100 has a structure in which a first metal layer 101, a conductor layer 102, a second metal layer 103, and a third metal layer 104 are stacked in this order from above along the z-axis direction. The current collector 100 is a laminated current collector in which multiple layers are stacked. As will be described in detail later, the current collector 100 is, for example, a current collector for stacking a positive electrode layer directly on the first metal layer 101. More specifically, when the current collector 100 is used in a battery, for example, the first metal layer 101 is bonded to the positive electrode layer, and the third metal layer 104 is bonded to the negative electrode layer. The current collector 100 is used, for example, to connect stacked power generating elements in series.

[0051] The current collector 100 is, for example, in the form of a sheet with the thickness direction being in the z-axis direction. The shape of the current collector 100 in plan view is, for example, rectangular, but is not particularly limited to this. In this specification, in cross-sectional views such as FIG. 1, the thickness of each layer is exaggerated to make the layer structure of the current collector 100 etc. easier to understand. Therefore, the thickness ratio of each layer in each drawing may not match the actual thickness.

[0052] Next, each layer of the current collector 100 will be described in detail.

[0053] [1.First metal layer] The first metal layer 101 is a metal current collecting layer bonded to the positive electrode layer. The first metal layer 101 is, for example, a metal foil. The first metal layer 101 includes a first metal. The first metal layer 101 includes, for example, the first metal as a main component. In this specification, "a layer includes something as a main component," such as "the first metal layer 101 includes the first metal as a main component," means that the "something" accounts for the largest proportion of the materials contained in the constituent elements of the "layer." Furthermore, in this specification, when "a layer includes something as a main component," the proportion of the "something" among the materials contained in the constituent elements of the "layer" may be 50% or more, 70% or more, 90% or more, or 95% or more.

[0054] The first metal layer 101 is made of, for example, a first metal or an alloy containing the first metal. The alloy containing the first metal may contain elements other than the metal element, such as carbon. The content of elements other than the metal element in the alloy containing the first metal is, for example, 5% or less.

[0055] The first metal layer 101 may contain materials other than the first metal and the alloy containing the first metal. The proportion of materials other than the first metal and the alloy containing the first metal in the first metal layer 101 is, for example, 5% or less.

[0056] Moreover, the first metal layer 101 does not include, for example, the second metal and the third metal described below.

[0057] The first metal is, for example, aluminum or iron. This makes it more difficult for the first metal layer 101 to form an alloy with lithium and dissolve into the positive electrode layer when the first metal layer 101 is bonded to the positive electrode layer, thereby suppressing a deterioration in battery characteristics. When the first metal is iron, an example of an alloy containing the first metal is stainless steel.

[0058] The thickness of the first metal layer 101 is, for example, 3 μm or more, and may be 5 μm or more. When the first metal layer 101 is 3 μm or more, the mechanical strength is increased, defects such as breakage are less likely to occur during the manufacturing process, and the current collection function is likely to be improved. Furthermore, the thickness of the first metal layer 101 is, for example, 50 μm or less, and may be 20 μm or less. When the thickness of the first metal layer 101 is 50 μm or less, the energy density of a battery using the current collector 100 can be increased.

[0059] [2. Conductive layer] The conductor layer 102 is disposed opposite the first metal layer 101. The conductor layer 102 is located between the first metal layer 101 and the second metal layer 103. The conductor layer 102 is in contact with, for example, both the first metal layer 101 and the second metal layer 103. Due to the wettability of the surface of the first metal layer 101, the absence of the conductor layer 102 would tend to result in poor contact between the first metal layer 101 and the second metal layer 103, resulting in reduced bonding strength. However, the presence of the conductor layer 102 improves the bonding strength between the first metal layer 101 and the second metal layer 103. As a result, the electrical resistance of the current collector 100 can be reduced, thereby improving battery characteristics.

[0060] The conductor layer 102 includes a conductive carbon material. The conductor layer 102 includes, for example, a conductive carbon material as a main component. The conductive carbon material is not particularly limited as long as it is a carbon material that is conductive. Examples of conductive carbon materials include carbon blacks such as acetylene black, Ketjen Black (registered trademark), thermal black, and furnace black; carbon fibers such as carbon nanotubes and carbon nanofibers; activated carbon; graphite; and graphene. The conductor layer 102 may include only one type of conductive carbon material, or may include two or more types of materials. The conductor layer 102 may also be a non-metallic conductor layer that does not include a metal material.

[0061] The thickness of the conductive layer 102 is, for example, 0.1 μm or more and 2.0 μm or less. When the thickness of the conductive layer 102 is 0.1 μm or more, the bonding strength between the first metal layer 101 and the second metal layer 103 can be improved, and the electrical resistance can be effectively reduced. Furthermore, when the thickness of the conductive layer 102 is 2.0 μm or less, the energy density of a battery using the current collector 100 can be increased.

[0062] The conductive layer 102 may further contain a resin. Examples of the resin include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polymethyl ester of acrylic acid, polyethyl ester of acrylic acid, polyhexyl ester of acrylic acid, polymethacrylic acid, polymethyl ester of methacrylic acid, polyethyl ester of methacrylic acid, polyhexyl ester of methacrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene-butadiene rubber, and carboxymethyl cellulose. The resin may be a copolymer of two or more materials selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene. The resin may be a curable resin that is cured by heat or light, such as an epoxy resin or a silicone resin. The conductive layer 102 may contain only one of these resins, or may contain two or more of these resins. When the conductive layer 102 contains a conductive carbon material and a resin, the proportion of the conductive carbon material in the conductive layer 102 is, for example, 50% or more and 95% or less.

[0063] The method for forming the conductive layer 102 is not particularly limited, and examples thereof include a method of applying a paste containing a conductive carbon material and a resin onto the first metal layer 101. The method for applying the paste is not particularly limited, and general application methods can be used. The applied paste may be dried as needed. If the resin is a curable resin, a curing process is performed after application. Alternatively, the conductive layer 102 may be formed by forming a film of the conductive carbon material on the first metal layer 101 by a spin coating method or the like using a dispersion liquid in which the conductive carbon material is dispersed. Alternatively, the conductive layer 102 may be formed by carbonizing a resin material such as polyimide formed on the first metal layer 101.

[0064] [3.Second metal layer] The second metal layer 103 is a thin metal film formed by, for example, vapor deposition. The second metal layer 103 is disposed opposite the first metal layer 101 with the conductive layer 102 sandwiched therebetween. The second metal layer 103 is located between the conductive layer 102 and the third metal layer 104. The second metal layer 103 is in contact with both the conductive layer 102 and the third metal layer 104, for example.

[0065] The second metal layer 103 includes a second metal. For example, the second metal layer 103 includes the second metal as a main component.

[0066] Moreover, the second metal layer 103 does not include, for example, the first metal and the third metal described below.

[0067] The second metal is, for example, a metal different from the first metal. Specifically, the second metal is, for example, chromium or titanium. This makes it easier to form the second metal layer 103 with high hardness.

[0068] The second metal layer 103 is made of, for example, the second metal, but may also be made of an alloy containing the second metal. The second metal layer 103 may also contain a material other than the second metal and the alloy containing the second metal. The proportion of the material other than the second metal and the alloy containing the second metal in the second metal layer 103 is, for example, 5% or less.

[0069] The thickness of the second metal layer 103 is, for example, 0.1 μm or more and 0.5 μm or less. When the thickness of the second metal layer 103 is 0.1 μm or more, even when pressure is applied when forming the battery, the negative electrode layer and the first metal layer 101 are less likely to come into contact with each other, and deterioration of the first metal layer 101 can be suppressed. Furthermore, when the thickness of the second metal layer 103 is 0.5 μm or less, the second metal layer 103 is less likely to peel off. Furthermore, the second metal layer 103 is suppressed from being formed in a scale-like shape, and the second metal layer 103 can be easily formed with a uniform thickness.

[0070] The second metal layer 103 is formed by depositing it on the conductor layer 102 by, for example, a vapor deposition method such as vacuum deposition. At this time, the presence of the conductor layer 102 makes it possible to obtain a good film in the formation of the second metal layer 103. Specifically, when a metal film is formed on the surface of the first metal layer 101, the metal tends to be unevenly distributed due to the influence of wettability, but the presence of the conductor layer 102 between the second metal layer 103 and the first metal layer 101 makes it possible to form the second metal layer 103 on the conductor layer 102 with a predetermined uniform thickness.

[0071] Furthermore, for example, when comparing the hardness of the first metal layer 101 and the second metal layer 103, the second metal layer 103 is harder than the first metal layer 101. For example, the Young's modulus of the second metal layer 103 is higher than the Young's modulus of the first metal layer 101.

[0072] [4.Third metal layer] The third metal layer 104 is a metal thin film formed by, for example, vapor deposition, etc. The third metal layer 104 is disposed opposite the conductor layer 102 with the second metal layer 103 interposed therebetween. The third metal layer 104 is in contact with the second metal layer 103, for example.

[0073] The third metal layer 104 includes a third metal. The third metal layer 104 includes, for example, the third metal as a main component.

[0074] Moreover, the third metal layer 104 does not include, for example, the first metal and the second metal.

[0075] The third metal is a metal different from the first metal and the second metal. Specifically, the third metal is, for example, nickel or copper. This makes it difficult for the third metal layer 104 to form an alloy with lithium and for lithium to dissolve into the negative electrode layer when the third metal layer 104 is bonded to the negative electrode layer, thereby preventing a decrease in battery performance. Furthermore, nickel and copper have low electrical resistance among metals, and reducing the electrical resistance of the current collector 100 can improve battery performance.

[0076] The third metal layer 104 is made of, for example, the third metal, but may also be made of an alloy containing the third metal. The third metal layer 104 may also contain a material other than the third metal and the alloy containing the third metal. The proportion of the material other than the third metal and the alloy containing the third metal in the third metal layer 104 is, for example, 5% or less.

[0077] Thus, the current collector 100 has a configuration in which the second metal layer 103 and the third metal layer 104, which are made of different metals, are stacked. By appropriately selecting the second metal and the third metal, it is possible to realize a current collector 100 that has both compatibility with the bonding suitability to the negative electrode layer and mechanical strength. Furthermore, when forming the metal layer by vapor deposition or the like, by forming the second metal layer 103 and the third metal layer 104, it is possible to form a metal layer with a uniform thickness, compared to forming a metal layer with a total thickness of the second metal layer 103 and the third metal layer 104 as a single metal layer.

[0078] The thickness of the third metal layer 104 is, for example, 0.5 μm or more and 1.5 μm or less. When the thickness of the third metal layer 104 is 0.5 μm or more, the negative electrode layer and the first metal layer 101 are less likely to come into contact with each other, and deterioration of the first metal layer 101 can be suppressed. Furthermore, when the thickness of the third metal layer 104 is 1.5 μm or less, the third metal layer 104 is less likely to peel off. Furthermore, the third metal layer 104 is prevented from being formed in a scale-like shape, and the third metal layer 104 can be easily formed with a uniform thickness. As a result, defects in the bonding between the third metal layer 104 and the negative electrode layer are less likely to occur.

[0079] Furthermore, the thickness of the third metal layer 104 is greater than the thickness of the second metal layer 103, for example. As a result, the third metal layer 104 containing copper or nickel becomes thicker, so that the electrical resistance of the current collector 100 is less likely to increase, and deterioration of the battery characteristics can be suppressed.

[0080] Furthermore, the sum of the thickness of second metal layer 103 and the thickness of third metal layer 104 may be smaller than the thickness of first metal layer 101. This makes it possible to increase the energy density of a battery using current collector 100. From the viewpoint of further increasing the energy density of the battery, the sum of the thickness of conductor layer 102, the thickness of second metal layer 103 and the thickness of third metal layer 104 may be smaller than the thickness of first metal layer 101.

[0081] The third metal layer 104 is formed by depositing a film on the second metal layer 103 by, for example, a vapor deposition method such as vacuum deposition. In this case, if the second metal layer 103 is a thin metal film formed by vapor deposition or the like, the wettability of the surface of the second metal layer 103 is stable, and therefore, the phenomenon of uneven distribution of metal is unlikely to occur during the vapor deposition of the third metal layer 104.

[0082] Furthermore, for example, when comparing the hardness of the second metal layer 103 and the third metal layer 104, the second metal layer 103 is harder than the third metal layer 104. For example, the Young's modulus of the second metal layer 103 is higher than that of the third metal layer 104. Because the second metal layer 103 is harder, the second metal layer 103 is less likely to break when the layers of the battery are compressed during battery formation, and the anode layer is less likely to come into contact with the first metal layer 101. This prevents deterioration of battery characteristics due to deterioration of the first metal layer 101, and further allows for increased compression pressure during battery formation, thereby improving the energy density of the battery. Furthermore, because the third metal layer 104, which is bonded to the anode layer, is softer, the contact resistance between the anode layer and the third metal layer 104 is less likely to be high. Furthermore, soft metals tend to have low electrical resistance, which can reduce the electrical resistance of the current collector 100 itself.

[0083] Although the current collector 100 has been described as being used to connect stacked power generating elements in series, when used to connect stacked power generating elements in parallel, the current collector may have a structure in which a conductor layer 102, a second metal layer 103, and a third metal layer 104 are stacked on each of the main surfaces on both sides of a first metal layer 101.

[0084] [Manufacturing method of current collector] Next, a method for manufacturing the current collector 100 will be described. The current collector 100 is manufactured, for example, as follows. Note that the method for manufacturing the current collector 100 is not limited to the following example.

[0085] First, a metal foil made of a first metal or an alloy containing the first metal is prepared as the first metal layer 101. For example, an aluminum foil or a stainless steel foil is prepared as the metal foil. Then, a paste containing a conductive carbon material and a resin is applied to one side of the prepared metal foil as the material for the conductive layer 102, thereby forming the conductive layer 102 on the first metal layer 101.

[0086] Next, a second metal layer 103 is formed by depositing a second metal by vacuum deposition on the surface of the conductive layer 102 formed on the first metal layer 101, opposite the first metal layer 101. Because conductive carbon materials have good wettability with metals, by depositing the second metal layer 103 on the conductive layer 102, the second metal can be deposited with a uniform thickness.

[0087] Next, a third metal layer 104 is formed by vacuum deposition on the surface opposite the conductive layer 102 of the second metal layer 103 formed on the conductive layer 102. Because the surface of the second metal layer 103, which is a vapor-deposited film, has stable wettability, the third metal is less likely to be unevenly distributed when vapor-deposited. Furthermore, when forming a metal layer on the conductive layer 102 to a predetermined thickness so that the anode layer is less likely to come into contact with the first metal layer 101 during battery formation, forming two layers, the second metal layer 103 and the third metal layer 104, results in a structure that is less susceptible to peeling, even at the same thickness, compared to forming a single layer.

[0088] The current collector 100 is obtained through the above steps. By manufacturing the current collector 100 in this manner, it is possible to manufacture the current collector 100 in a manner that prevents deterioration even when used as a single current collector to connect power generating elements in series, without causing uneven distribution of the metal that constitutes the metal layer. This further prevents deterioration of battery characteristics.

[0089] (Embodiment 2) Next, a description will be given of embodiment 2. Specifically, in embodiment 2, a battery using the current collector 100 according to embodiment 1 will be described. The battery according to this embodiment is a battery including one or more power generating elements.

[0090] [Battery configuration] First, a battery including one power generating element will be described. Fig. 2 is a cross-sectional view showing a schematic configuration of a battery 300 according to this embodiment.

[0091] 2, the battery 300 includes a current collector 100, a power generating element 200 having a positive electrode layer 201, a solid electrolyte layer 202, and a negative electrode layer 203, and a current collector 110. The battery 300 is, for example, an all-solid-state battery. The battery 300 has a structure in which the current collector 100, the positive electrode layer 201, the solid electrolyte layer 202, the negative electrode layer 203, and the current collector 110 are stacked in this order from the bottom along the z-axis direction. The current collector 100, the positive electrode layer 201, the solid electrolyte layer 202, the negative electrode layer 203, and the current collector 110 have, for example, the same shape and the same outline in a plan view.

[0092] The area of ​​the main surface of the battery 300 is, for example, 1 cm for a battery for a portable electronic device such as a smartphone or a digital camera. 2 More than 100cm 2 The area of ​​the main surface of the battery 300 is 100 cm or less for a battery used as a power source for large mobile devices such as electric vehicles. 2 More than 1000cm 2 It may be the following:

[0093] The shape of the battery 300 is, for example, a flat rectangular parallelepiped with the length in the stacking direction being the shortest. The shape of the battery 300 is not particularly limited and may be other shapes such as a cube, a cylinder, a truncated square pyramid, a truncated cone, or a polygonal column. The shape of the battery 300 in a plan view is, for example, a rectangle. The shape of the battery 300 in a plan view may be other quadrilaterals such as a square, a parallelogram, or a rhombus, other polygons such as a hexagon or an octagon, a circle, or an ellipse.

[0094] The power generating element 200 is an example of a first power generating element that is located on the current collector 100 and stacked adjacent to the current collector 100. The power generating element 200 is located between the current collector 100 and the current collector 110. The battery 300 is required to include at least one power generating element 200, and may include multiple power generating elements 200. A battery including multiple power generating elements 200 will be described later.

[0095] The positive electrode layer 201 is disposed opposite the negative electrode layer 203. The positive electrode layer 201 is located between the current collector 100 and the solid electrolyte layer 202. The positive electrode layer 201 faces the first metal layer 101 of the current collector 100 without the solid electrolyte layer 202 or the conductor layer 102 interposed therebetween. The positive electrode layer 201 is in contact with, for example, both the first metal layer 101 and the solid electrolyte layer 202. The positive electrode layer 201 is bonded to the first metal layer 101 of the current collector 100. The positive electrode layer 201 may be bonded to the first metal layer 101 via a conductive connection layer containing a conductive carbon material or the like.

[0096] The positive electrode layer 201 includes at least a positive electrode active material, and may be a positive electrode mixture layer including the positive electrode active material and other materials such as a solid electrolyte.

[0097] The positive electrode active material contained in the positive electrode layer 201 is, for example, a material that absorbs and releases metal ions. The positive electrode active material may be, for example, a material that absorbs and releases lithium ions. Examples of the positive electrode active material contained in the positive electrode layer 201 include lithium-containing transition metal oxides, transition metal fluorides, polyanions, fluorinated polyanion materials, transition metal sulfides, transition metal oxyfluorides, transition metal oxysulfides, and transition metal oxynitrides. In particular, when a lithium-containing transition metal oxide is used as the positive electrode active material, the manufacturing cost can be reduced and the average discharge voltage can be increased. The solid electrolyte used in the positive electrode layer 201 will be described later.

[0098] The thickness of the positive electrode layer 201 may be 10 μm or more and 500 μm or less. When the thickness of the positive electrode layer 201 is 10 μm or more, it is easy to ensure a sufficient energy density of the battery. When the thickness of the positive electrode layer 201 is 500 μm or less, it is easy to operate at high output.

[0099] The negative electrode layer 203 is disposed opposite the positive electrode layer 201. The negative electrode layer 203 is located between the current collector 110 and the solid electrolyte layer 202. The negative electrode layer 203 is in contact with, for example, both the current collector 110 and the solid electrolyte layer 202. The negative electrode layer 203 is bonded to, for example, the current collector 110. The negative electrode layer 203 may be bonded to the current collector 110 via a conductive connection layer containing a conductive carbon material or the like.

[0100] The negative electrode layer 203 includes at least a negative electrode active material, and may be a negative electrode mixture layer including the negative electrode active material and other materials such as a solid electrolyte.

[0101] The negative electrode active material contained in the negative electrode layer 203 is, for example, a material that absorbs and releases metal ions. The negative electrode active material may be, for example, a material that absorbs and releases lithium ions. Examples of the negative electrode active material contained in the negative electrode layer 203 include lithium metal, metals or alloys that exhibit an alloying reaction with lithium, carbon materials, transition metal oxides, and transition metal sulfides. Examples of the carbon material include graphite, or non-graphite carbon materials such as hard carbon and coke. Examples of the transition metal oxide include CuO and NiO. Examples of the transition metal sulfide include copper sulfide represented by CuS. Examples of the metal or alloy that exhibits an alloying reaction with lithium include alloys of lithium with silicon compounds, tin compounds, or aluminum compounds. Using a carbon material can reduce manufacturing costs and increase the average discharge voltage. The solid electrolyte used in the negative electrode layer 203 will be described later.

[0102] The thickness of the negative electrode layer 203 may be 10 μm or more and 500 μm or less. When the thickness of the negative electrode layer 203 is 10 μm or more, it is easy to ensure a sufficient energy density of the battery. When the thickness of the negative electrode layer 203 is 500 μm or less, it is easy to operate at high output.

[0103] At least one of the positive electrode layer 201 and the negative electrode layer 203 may contain a conductive additive to enhance electronic conductivity. Examples of conductive additives that can be used include natural or artificial graphite, carbon black such as acetylene black or ketjen black, conductive fibers such as carbon fiber or metal fiber, metal powders such as carbon fluoride or aluminum, conductive whiskers such as zinc oxide or potassium titanate, conductive metal oxides such as titanium oxide, and conductive polymer compounds such as polyaniline, polypyrrole, or polythiophene. Using a carbon material conductive additive can reduce costs.

[0104] The solid electrolyte layer 202 is located between the positive electrode layer 201 and the negative electrode layer 203. The solid electrolyte layer 202 is in contact with both the positive electrode layer 201 and the negative electrode layer 203.

[0105] The solid electrolyte layer 202 includes at least a solid electrolyte. The solid electrolyte used in the solid electrolyte layer 202 will be described later.

[0106] The thickness of the solid electrolyte layer 202 may be 1 μm or more and 200 μm or less. When the thickness of the solid electrolyte layer 202 is 1 μm or more, it is possible to prevent a short circuit between the positive electrode layer 201 and the negative electrode layer 203. When the thickness of the solid electrolyte layer 202 is 200 μm or less, it is easy to operate at high output.

[0107] The solid electrolyte contained in the positive electrode layer 201, the negative electrode layer 203, and the solid electrolyte layer 202 may be, for example, a sulfide solid electrolyte, an oxide solid electrolyte, a halide solid electrolyte, a polymer solid electrolyte, or a complex hydride solid electrolyte. The solid electrolyte has, for example, lithium ion conductivity.

[0108] Examples of sulfide solid electrolytes include Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, and Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 In addition to these, LiX (X is F, Cl, Br, or I), Li2O, MO p , Li q MO r (wherein M is any of P, Si, Ge, B, Al, Ga, In, Fe, and Zn, and p, q, and r are natural numbers), etc. may be added.

[0109] Examples of oxide solid electrolytes include NASICON-type solid electrolytes, such as LiTi2(PO4)3 and its elemental substitution products, (LaLi)TiO3-based perovskite-type solid electrolytes, and Li 14 ZnGeO 16 , Li4SiO4, LiGeO4 and their element-substituted LISICON-type solid electrolytes, Li7La3Zr2O 12 Garnet-type solid electrolytes, such as those typified by element substitution products thereof, Li3N and its H-substituted products, Li3PO4 and its N-substituted products, and glasses or glass ceramics based on Li-BO compounds such as LiBO2 and Li3BO3 to which Li2SO4, Li2CO3, etc. have been added, can be used.

[0110] The halide solid electrolyte may be, for example, a compound having the composition formula Li α M β X γwhere α, β, and γ are greater than 0, M includes at least one metal element and metalloid element other than Li, and X is one or more elements selected from the group consisting of Cl, Br, I, and F. Here, metalloid elements are B, Si, Ge, As, Sb, and Te. Metal elements include all elements in Groups 1 to 12 of the periodic table except for hydrogen, as well as all elements in Groups 13 to 16 except for the above metalloid elements and C, N, P, O, S, and Se. In other words, these elements are a group of elements that can become cations when forming inorganic compounds with halogen compounds. Examples of halide solid electrolytes that can be used include Li3YX6, Li2MgX4, Li2FeX4, Li(Al, Ga, In)X4, and Li3(Al, Ga, In)X6 (X is F, Cl, Br, or I).

[0111] As the complex hydride solid electrolyte, for example, LiBH4-LiI or LiBH4-P2S5 can be used.

[0112] As the polymer solid electrolyte, for example, a compound of a polymer compound and a lithium salt can be used. The polymer compound may have an ethylene oxide structure. When the polymer compound has an ethylene oxide structure, it can contain a large amount of lithium salt, thereby further increasing ionic conductivity. Examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), and LiC(SO2CF3)3. As the lithium salt, one type of lithium salt selected from these can be used alone. Alternatively, as the lithium salt, a mixture of two or more types of lithium salts selected from these can be used.

[0113] At least one of the positive electrode layer 201, the solid electrolyte layer 202, and the negative electrode layer 203 may contain a binder to improve adhesion between particles. The binder is used to improve the binding of the materials constituting the electrodes. Examples of binders include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polymethyl ester of acrylic acid, polyethyl ester of acrylic acid, polyhexyl ester of acrylic acid, polymethacrylic acid, polymethyl ester of methacrylic acid, polyethyl ester of methacrylic acid, polyhexyl ester of methacrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene-butadiene rubber, and carboxymethyl cellulose. The binder may be a copolymer of two or more materials selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene. Alternatively, a mixture of two or more materials selected from these may be used as the binder.

[0114] The current collector 100 is stacked adjacent to the power generating element 200 on the side of the positive electrode layer 201 of the power generating element 200. Specifically, the first metal layer 101 of the current collector 100 faces the positive electrode layer 201 of the power generating element 200 without the solid electrolyte layer 202 of the power generating element 200 or the conductor layer 102 of the current collector 100 interposed therebetween. The first metal layer 101 is in contact with, for example, the positive electrode layer 201. The first metal layer 101 faces the negative electrode layer 203 of the power generating element 200 via the positive electrode layer 201 and the solid electrolyte layer 202, but is not in contact with the negative electrode layer 203. As described above, the first metal layer 101 contains the first metal that is different from the third metal, which is nickel or copper. Therefore, even when joined to the positive electrode layer 201, deterioration or the like is unlikely to occur. This can suppress deterioration of the battery characteristics of a battery 300 using the current collector 100.

[0115] Furthermore, because the first metal layer 101 of the current collector 100 is bonded to the positive electrode layer 201, the third metal layer 104 of the current collector 100 is exposed at the bottom of the battery 300 and can be bonded to other power-generating elements. Furthermore, because the third metal layer 104 contains a third metal, such as nickel or copper, it is less likely to deteriorate even when bonded to the negative electrode layer. Therefore, even when the battery 300 is bonded to the negative electrode layer without another current collector interposed therebetween and electrically connected in series with other power-generating elements, the battery characteristics are less likely to deteriorate. Therefore, when the battery 300 is electrically connected in series with other power-generating elements, the number of current collectors used can be reduced, thereby increasing the energy density.

[0116] The current collector 110 is stacked adjacent to the power generating element 200 on the negative electrode layer 203 side of the power generating element 200. Specifically, the current collector 110 faces the negative electrode layer 203 of the power generating element 200 without the solid electrolyte layer 202 of the power generating element 200 being interposed therebetween. The current collector 110 is in contact with the negative electrode layer 203, for example. In this embodiment, the current collector 110 is a negative electrode current collector that exchanges electrons with the negative electrode layer 203.

[0117] A known material for a negative electrode current collector can be used as the material for the current collector 110. The current collector 110 is, for example, a metal foil made of copper, nickel, or iron, or an alloy containing at least one of copper, nickel, and iron. Unlike the current collector 100, the current collector 110 does not have a laminated structure and is made of a single metal foil.

[0118] The thickness of the current collector 110 is, for example, not less than 3 μm and not more than 50 μm.

[0119] The battery 300 may include the current collector 100 instead of the current collector 110. That is, the power generating element 200 may be located between two current collectors 100. In this case, the power generating element 200 and the current collectors 100 are stacked so that the third metal layer 104 of the current collector 100 is joined to the negative electrode layer 203.

[0120] The battery 300 may be housed in an exterior body to protect the power generating element 200, etc. The exterior body may be a resin-laminated metal foil having a resin film on one or both sides of a metal foil. A specific example of the exterior body is a resin-laminated metal foil having a resin film laminated on one side of a metal foil to impart mechanical strength, and a resin film having heat-sealability laminated on the opposite side.

[0121] The metal foil in the resin-laminated metal foil may be, for example, a foil made of aluminum or an aluminum alloy. The resin film for maintaining mechanical strength may be, for example, a film made of polyester or nylon. The resin film having heat-sealability may be, for example, a film made of polyolefin, specifically, for example, a film made of polyethylene or polypropylene.

[0122] The laminate film constituting the exterior body may be embossed on one or both sides.

[0123] Next, a battery including a plurality of power generating elements will be described. Fig. 3 is a cross-sectional view showing a schematic configuration of a battery 400 according to this embodiment. In the following description of battery 400, differences from battery 300 will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0124] As shown in FIG. 3 , the battery 400 includes a plurality of current collectors 100, a plurality of power generating elements 200, and a current collector 110. The battery 400 has a configuration in which the current collectors 100 and the power generating elements 200 are further stacked on top of the battery 300. In the following description, the plurality of power generating elements 200 included in the battery 400 may be referred to as power generating element 200a, power generating element 200b, and power generating element 200c, arranged in order from the top. The plurality of current collectors 100 included in the battery 400 may be referred to as current collector 100a, current collector 100b, and current collector 100c, arranged in order from the top. The power generating element 200a is an example of a first power generating element, and the power generating element 200b is an example of a second power generating element that is stacked adjacent to the first power generating element with the current collector 100a interposed therebetween.

[0125] Current collectors 100 are disposed between adjacent power generating elements 200. In the battery 400, of the multiple current collectors 100, current collector 100a and current collector 100b are each located between adjacent power generating elements 200. Specifically, current collector 100a is located between adjacent power generating elements 200a and 200b, and current collector 100b is located between adjacent power generating elements 200b and 200c. Furthermore, current collector 100c is located below the lowermost power generating element 200c of the multiple power generating elements 200.

[0126] The current collectors located at the top and bottom of battery 400 may be current collector 100 having a laminated structure, or current collectors made of metal foil or the like without a laminated structure may be used. For example, current collector 100 may be disposed instead of current collector 110 located at the top, and a current collector made of metal foil such as aluminum foil may be disposed instead of current collector 100c located at the bottom.

[0127] The multiple power generating elements 200 are stacked in the same stacking order from the top. Therefore, the multiple power generating elements 200 are connected to each other by the current collectors 100, and are thus electrically connected in series. This makes it possible to increase the voltage of the battery 400. Furthermore, because a common current collector 100 is disposed between adjacent power generating elements 200, the number of current collectors used in the battery 400 can be reduced. As a result, the energy density can be improved by reducing the number of current collectors that do not contribute to power generation, and deterioration of battery characteristics can be suppressed by eliminating the need to connect current collectors to each other.

[0128] In the battery 400, the number of the power generating elements 200 is three, but is not particularly limited and may be two, four, or more. The more the number of the power generating elements 200 increases, the higher the voltage of the battery can be. Any number can be set taking into consideration the ease of handling during battery manufacturing, the loading space of the device using the battery, and the control voltage of the device using the battery. For example, two to 500 power generating elements 200 may be electrically connected in series.

[0129] The positional relationships between the current collector 100a and the power generating element 200a, the current collector 100b and the power generating element 200b, and the current collector 100c and the power generating element 200c are the same as the positional relationship between the current collector 100 and the power generating element 200 in the battery 300 described above.

[0130] The third metal layer 104 of the current collector 100a faces the negative electrode layer 203 of the power generating element 200b without the solid electrolyte layer 202 of the power generating element 200b or the second metal layer 103 of the current collector 100a interposed therebetween. The third metal layer 104 of the current collector 100a is in contact with, for example, the negative electrode layer 203 of the power generating element 200b. The negative electrode layer 203 of the power generating element 200b is bonded to, for example, the third metal layer 104 of the current collector 100a. The negative electrode layer 203 of the power generating element 200b may be bonded to the third metal layer 104 of the current collector 100a via a conductive connection layer containing a conductive carbon material or the like.

[0131] As described above, the third metal layer 104 contains the third metal, which is nickel or copper, and therefore is less susceptible to deterioration even when joined to the negative electrode layer 203. This can prevent deterioration in the battery characteristics of the battery 400 using the current collector 100. The same can be said about the current collector 100b and the power generating element 200c.

[0132] As described above, in the battery 400, the adjacent power generating elements 200a and 200b are stacked with the current collector 100a interposed therebetween. The positive electrode layer 201 of the power generating element 200a and the first metal layer 101 of the current collector 100a are arranged adjacent to each other, and the negative electrode layer 203 of the power generating element 200b and the third metal layer 104 of the current collector 100a are arranged adjacent to each other. This electrically connects the power generating element 200a and the power generating element 200b in series. Because the power generating element 200a and the power generating element 200b are stacked with one current collector 100a interposed therebetween, the number of current collectors used can be reduced, resulting in a battery with high energy density. The first metal layer 101 of the current collector 100a is stacked with the positive electrode layer 201 of the power generating element 200a without any other layer interposed therebetween. However, because it contains the first metal, which is different from the third metal, which is nickel or copper, it is less likely to deteriorate. Furthermore, the third metal layer 104 of the current collector 100a is laminated with the negative electrode layer 203 of the power generating element 200b without any other layer in between, but since it contains the third metal, which is nickel or copper, it is less likely to deteriorate, etc. Therefore, it is possible to suppress deterioration in the battery characteristics of the battery 400 using the current collector 100a.

[0133] [Battery manufacturing method] Next, a description will be given of a method for manufacturing the battery 300 and the battery 400. The battery 300 and the battery 400 are manufactured, for example, as follows. Note that the method for manufacturing the battery 300 and the battery 400 is not limited to the following example.

[0134] First, the positive electrode layer 201 is formed on the current collector 100. Specifically, a slurry is prepared by mixing a positive electrode active material, a solvent, and, if necessary, at least one of a solid electrolyte, a binder, and a conductive additive. The prepared slurry is then die-coated onto the surface of the first metal layer 101 of the current collector 100 opposite the conductive layer 102. The coating method is not particularly limited, and a general coating method can be used. The slurry is then dried to obtain the positive electrode layer 201 with a predetermined thickness and shape. Furthermore, the positive electrode layer 201 may be pressed after drying, if necessary.

[0135] Next, the solid electrolyte layer 202 is formed on the positive electrode layer 201 formed above. Specifically, a slurry is prepared by mixing a solid electrolyte, a solvent, and, if necessary, a binder. The prepared slurry is then die-coated onto the surface of the positive electrode layer 201 formed above opposite the current collector 100 side. The coating method in this case is not limited, and a general coating method can be used. The slurry is then dried to obtain the solid electrolyte layer 202 with a predetermined thickness. Furthermore, the solid electrolyte layer 202 may be pressed after drying, if necessary.

[0136] Next, the negative electrode layer 203 is formed on the solid electrolyte layer 202 formed above. Specifically, a slurry is prepared by mixing a negative electrode active material, a solvent, and, if necessary, at least one of a solid electrolyte, a binder, and a conductive additive. The prepared slurry is then die-coated onto the surface of the solid electrolyte layer 202 formed above opposite to the positive electrode layer 201. The coating method in this case is not limited, and a general coating method can be used. The slurry is then dried to obtain the negative electrode layer 203 with a predetermined thickness. If necessary, the negative electrode layer 203 may be pressurized after drying.

[0137] Through the above steps, a laminated plate is obtained in which the power generating element 200 is laminated on the current collector 100. The obtained laminated plate may be cut to a predetermined size as needed. The cutting method is not particularly limited, and a general cutting method such as shearing using a blade may be used.

[0138] The number of laminated plates to be produced corresponds to the number of power generating elements 200 to be connected. The number of laminated plates to be produced is not particularly limited, but for example, one for the battery 300 and three for the battery 400.

[0139] Next, to manufacture the battery 400, the required number of prepared laminates are stacked so that the power generating elements 200 are electrically connected in series. That is, multiple laminates are stacked so that the third metal layer 104 of one current collector 100 of adjacent laminates faces the negative electrode layer 203 of the other power generating element 200. Then, a current collector 110 is placed on the uppermost negative electrode layer 203 to obtain the battery 400. At this time, the obtained battery 400 may be pressurized as needed. Furthermore, electrical terminals may be connected to the top and bottom of the battery 400 as needed, and the obtained battery 400 may be housed in an exterior body. The shapes of the terminals and the exterior body are not particularly limited. The battery 300 can be manufactured by the above method without stacking laminates, but by placing a current collector 110 on the negative electrode layer 203 of one laminate body.

[0140] (Other embodiments) While the battery according to the present disclosure has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications conceivable by those skilled in the art to the embodiments and other forms constructed by combining some of the components of the embodiments are also included in the scope of the present disclosure.

[0141] For example, in the above embodiment, current collector 100 is configured with first metal layer 101, conductive layer 102, second metal layer 103, and third metal layer 104, but this is not limiting. Current collector 100 may include layers other than first metal layer 101, conductive layer 102, second metal layer 103, and third metal layer 104. For example, another metal layer or conductive layer may be present between any two adjacent layers of first metal layer 101, conductive layer 102, second metal layer 103, and third metal layer 104.

[0142] Furthermore, for example, in the above embodiment, in the battery 300, the first metal layer 101 of the current collector 100 faces the positive electrode layer 201 of the power generating element 200 without the solid electrolyte layer 202 of the power generating element 200 and the conductor layer 102 of the current collector 100 interposed therebetween. However, this is not limited to this. The third metal layer 104 of the current collector 100 may face the negative electrode layer 203 of the power generating element 200 without the solid electrolyte layer 202 of the power generating element 200 and the second metal layer 103 of the current collector 100 interposed therebetween. For example, the current collector 100 and the power generating element 200 may be laminated such that the third metal layer 104 is in contact with the negative electrode layer 203. Even in this case, since the third metal layer 104 containing nickel or copper is joined to the negative electrode layer 203, deterioration of the current collector 100 is suppressed. Furthermore, in the battery 300, even if the first metal layer 101 of the current collector 100 is joined to the positive electrode layer of another power generating element without sandwiching another current collector therebetween, the battery characteristics are unlikely to deteriorate.

[0143] Furthermore, for example, in the above embodiment, all of the power generating elements 200 in the battery 400 are electrically connected in series, but this is not limited to this. For example, the batteries 400 may be stacked in the reverse order, and the series-connected power generating elements 200 may be further connected in parallel.

[0144] Furthermore, the above-described embodiments and modifications can be subject to various changes, substitutions, additions, omissions, etc. within the scope of the claims or their equivalents. [Industrial Applicability]

[0145] The current collector and battery according to the present disclosure can be used in various batteries, such as all-solid-state lithium secondary batteries. [Explanation of symbols]

[0146] 100, 100a, 100b, 100c, 110 current collector 101 1st metal layer 102 Conductive layer 103 Second metal layer 104 Third metal layer 200, 200a, 200b, 200c Power generation elements 201 Positive Electrode Layer 202 Solid Electrolyte Layer 203 Negative Electrode Layer 300 and 400 batteries

Claims

1. a first metal layer comprising a first metal; a conductive layer containing a conductive carbon material; a second metal layer comprising a second metal; a third metal layer including a third metal different from the first metal and the second metal; have a structure in which the above are laminated in this order, the third metal is nickel or copper; the second metal layer is harder than the third metal layer; Current collector.

2. the first metal is aluminum or iron; The current collector according to claim 1 .

3. A first metal layer comprising a first metal; a conductive layer containing a conductive carbon material; a second metal layer comprising a second metal; a third metal layer including a third metal different from the first metal and the second metal; have a structure in which the above are laminated in this order, the third metal is nickel or copper; the second metal is titanium or chromium; Current collector.

4. the sum of the thickness of the second metal layer and the thickness of the third metal layer is smaller than the thickness of the first metal layer; The current collector according to claim 1 .

5. The thickness of the third metal layer is greater than the thickness of the second metal layer. The current collector according to claim 1 .

6. The thickness of the first metal layer is 3 μm or more and 50 μm or less. The current collector according to claim 1 .

7. The thickness of the second metal layer is 0.1 μm or more and 0.5 μm or less. The current collector according to claim 1 .

8. the thickness of the third metal layer is 0.5 μm or more and 1.5 μm or less; The current collector according to claim 1 .

9. The thickness of the conductive layer is 0.1 μm or more and 2.0 μm or less. The current collector according to claim 1 .

10. The current collector according to any one of claims 1 to 9; at least one power generating element including a positive electrode layer, a negative electrode layer disposed opposite the positive electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer; the at least one power generating element includes a first power generating element stacked adjacent to the current collector, the first metal layer of the current collector faces the positive electrode layer of the first power generating element without the solid electrolyte layer of the first power generating element and the conductor layer of the current collector interposed therebetween; battery.

11. the at least one power generating element further includes a second power generating element stacked adjacent to the first power generating element with the current collector interposed therebetween, the third metal layer of the current collector faces the negative electrode layer of the second power generating element without the solid electrolyte layer of the second power generating element and the second metal layer of the current collector interposed therebetween; The battery of claim 10.

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