JP6528814B2 - Clad material and electrode for battery current collector - Google Patents

Description

  The present invention relates to a clad material for a battery current collector and an electrode using the clad material for a battery current collector.

  Conventionally, a clad material for a battery current collector is known which is a clad material in which a layer composed of an Al-based alloy and a layer composed of a Cu-based alloy are joined (see, for example, Patent Document 1).

  In Patent Document 1, a lithium battery of a bipolar type provided with a clad material for a battery current collector (bipolar electrode) made of a clad material obtained by rolling an aluminum foil having a thickness of 20 μm and a copper foil having a thickness of 10 μm. An ion secondary battery is disclosed. The ratio of the thickness of the aluminum foil to the total thickness of the aluminum foil and the copper foil is about 67% (= (20 / (20 + 10)) × 100).

  However, in the clad material for a battery current collector described in Patent Document 1, since the ratio of the thickness of the aluminum foil is as large as about 67%, when the aluminum foil and the copper foil are joined by rolling, the aluminum foil is copper. The aluminum foil side is extended more than the copper foil side due to plastic deformation being easier than the foil. As a result, there is a disadvantage that the aluminum foil side of the battery current collector clad is largely warped to be convex. In addition, when the battery current collector clad material is heat treated and annealed, and then cooled to room temperature, the thermal expansion coefficient of the aluminum foil is greater than the thermal expansion coefficient of the copper foil, so the heat treatment is performed. At the time of subsequent cooling, the thermal contraction of the thick aluminum foil has a great influence. For this reason, there is also a disadvantage that the aluminum foil side of the battery current collector clad is largely warped to be concave.

  Conventionally, in order to solve the above-mentioned disadvantages, in Patent Document 2 below, a bipolar lithium ion secondary battery including a current collector made of a stainless steel foil having a surface roughened and having a thickness of 50 μm or less Has been proposed. Since the proposed current collector made of the conventional stainless steel foil is not a clad material, it is possible to suppress the occurrence of large warpage during rolling or cooling after heat treatment.

JP-A-8-7926 JP, 2010-33768, A

  However, in the current collector made of stainless steel foil described in Patent Document 2 described above, it is possible to suppress the occurrence of large warpage, but since stainless steel is a hard metal material, a slurry containing an active material is used. After applying and drying on the roughened surface of the current collector, it was solidified to adhere the active material to the roughened surface of the current collector by going through the process of applying pressure by roll pressing. Also, the active material does not bite into the surface of the current collector sufficiently. For this reason, it is thought that it is difficult to increase the contact area between the current collector and the active material, because the active material can not be sufficiently adhered to the current collector. As a result, it is considered that the contact resistance between the current collector and the active material is increased. Therefore, conventionally, there is a problem that it is difficult to suppress the occurrence of a large warpage and to suppress the increase in the contact resistance with the active material.

  Therefore, the present invention has been made to solve the problems as described above, and one object of the present invention is to suppress the occurrence of large warpage and increase the contact resistance with the active material. It is an object of the present invention to provide a clad material for a battery current collector that can suppress the problem and an electrode using the clad material for the battery current collector.

  The inventors of the present application have intensively studied to solve the above problems, and as a result, adjust the ratio of the thickness of the first layer composed of an Al-based alloy and the thickness of the second layer composed of a Cu-based alloy, It has been found that the above problem can be solved by providing a core material layer having a high Young's modulus.

That is, the clad material for a battery current collector according to the first aspect of the present invention is disposed on one surface and is disposed on the first surface composed of an Al-based alloy and the other surface and composed of a Cu-based alloy The second layer and the core layer disposed between the first layer and the second layer and having a Young's modulus of 150 GPa or more are made of a clad material joined by rolling, and the first layer and the second layer The ratio of the thickness of the first layer to the total thickness is 50% or less, and the thickness of the core layer is one third of the thickness of the clad material. Note that “Al-based alloy” is a broad concept that includes not only Al alloys but also pure Al containing 99 mass% or more of Al. In addition, “Cu-based alloy” is a broad concept including not only Cu alloys but also pure Cu containing 99 mass% or more of Cu. Further, because the clad material includes the first layer, the case where the thickness ratio of the first layer is 0% (when the first layer does not exist) is not included.

In the clad material for a battery current collector according to the first aspect of the present invention, as described above, the core material layer having a Young's modulus of 150 GPa or more is disposed between the first layer and the second layer of the clad material. . Thereby, even if the thickness ratio of the first layer made of an Al-based alloy which is easily plastically deformed is 50% or less and is relatively large, the Young's modulus is high, and the core layer contributes to the improvement of the rigidity of the clad material Thus, the influence of warpage caused by the Al-based alloy can be reduced during rolling. As a result, it is possible to suppress large warpage so that the first layer side of the battery current collector clad material becomes convex. Further, even at the time of cooling after heat treatment, the core layer that has a high Young's modulus and contributes to the improvement of the rigidity of the clad material can reduce the influence of the warpage caused by the large thermal contraction of the Al-based alloy, It is possible to suppress large warpage so that the first layer side of the battery current collector clad material becomes concave. As a result of these, it is possible to suppress the occurrence of large warpage in the battery current collector clad material. Also, by disposing a first layer composed of a flexible Al-based alloy on one surface of the clad material for battery current collector, and disposing a second layer composed of a flexible Cu-based alloy on the other surface, When the active material is disposed on the one surface and the other surface, the active material can be sufficiently adhered to the one surface and the other surface by the Al-based alloy and the Cu-based alloy that are softer than conventional stainless steel. The contact area between the battery and the clad material for battery current collector can be increased. This can suppress an increase in the contact resistance between the battery current collector clad material and the active material. Furthermore, by providing the flexible first layer and the second layer, reduction in the rolling processability can be suppressed as compared with the case where the battery current collector material is made of only a hard single stainless steel plate. Thus, the can be efficiently manufactured a battery current collector clad material, Ru can reduce costs by rolling.

  In the clad material for a battery current collector according to the first aspect, preferably, the core layer is made of a Ni-based alloy or an Fe-based alloy. According to this structure, since the ionization tendency of Ni and Fe is both Al and Cu, the metal element (Ni or Fe) mainly constituting the core layer and the Al mainly constituting the first layer Both the difference in ionization tendency and the difference in ionization tendency between the metal element mainly constituting the core layer and Cu mainly constituting the second layer can be reduced. Thus, it is possible to suppress the occurrence of corrosion between the core layer made of Ni-based alloy or Fe-based alloy and the first layer made of Al-based alloy, and also the core layer and the Cu-based alloy It is possible to suppress the occurrence of corrosion with the second layer composed of In addition, by using a Ni-based alloy or an Fe-based alloy as the core layer, an inexpensive core layer having a Young's modulus of 150 GPa or more can be easily obtained. The "Ni-based alloy" is a broad concept including not only Ni alloys but also pure Ni containing 99% by mass or more of Ni. In addition, “Fe-based alloy” is a broad concept including not only Fe alloys but also pure Fe containing at least 99 mass% of Fe.

  In this case, preferably, the core layer is made of a Ni-based alloy which is pure Ni or a Ni-Nb alloy containing Nb. According to this structure, since the Ni-Nb alloy containing pure Ni or Nb has a high Young's modulus, it can sufficiently contribute to the improvement of the rigidity of the clad material. Therefore, the occurrence of large warpage in the battery current collector clad material can be further suppressed.

  In the clad material for a battery current collector according to the first aspect, the thickness of the clad material is preferably 100 μm or less. Here, in a clad material having a small thickness of 100 μm or less, warpage is generally likely to occur. Therefore, in the present invention, by setting the ratio of the thickness of the first layer to 35% or less, or by providing the core material layer having a Young's modulus of 150 GPa or more, a battery collection with a small thickness of 100 μm or less tends to occur. It is possible to suppress the occurrence of large warpage in the cladding material for a current collector.

  In the electrode according to the second aspect, the positive electrode active material layer is disposed on one surface of the clad material for a battery current collector according to the first aspect, and the negative electrode active material layer is disposed on the other surface. Thus, it is possible to form a so-called bipolar electrode in which the positive electrode active material layer and the negative electrode active material layer are formed on one surface and the other surface, respectively, using the battery current collector clad material. Moreover, when forming an active material layer on the surface of the clad material for battery current collectors, and forming an electrode, after apply | coating the slurry containing an active material, heat processing is performed and it cools after that. In this case, as in the configuration of the first or second aspect, by setting the ratio of the thickness of the first layer to 35% or less, or by providing a core layer having a Young's modulus of 150 GPa or more, At the time of cooling after the heat treatment at the time of forming the active material layer, it is possible to suppress the occurrence of large warpage in the battery current collector clad material (electrode).

  According to the present invention, as described above, a clad material for a battery current collector capable of suppressing occurrence of a large warpage while suppressing an increase in contact resistance with an active material, and a battery current collector thereof An electrode using a body cladding material can be provided.

It is sectional drawing which showed the clad material for collectors by the reference example of this invention. It is the perspective view which showed the battery using the clad material for collectors by the reference example of this invention. It is a perspective view for demonstrating the curvature measurement of the width direction performed in order to confirm the effect of a reference example. It is a perspective view for demonstrating the curvature measurement of the longitudinal direction performed in order to confirm the effect of a reference example. It is the table which showed the result of the reference example. FIG. 1 is a cross-sectional view of a current-collector clad material according to an embodiment of the present invention. It is the table | surface which showed the result of the Example performed in order to confirm the effect of this invention.

  Hereinafter, an embodiment of the present invention will be described based on the drawings.

(Reference example)
First, with reference to FIG. 1 and FIG. 2, the structure of the clad material 1 for collectors by the reference example of this invention is demonstrated.

  As shown in FIG. 1, the clad material 1 for current collectors according to the reference example of the present invention has a function as a current collector of the secondary battery 101 (see FIG. 2). Specifically, the positive electrode active material layer 2 is formed on the surface 1a on one side (Z1 side) in the thickness direction (Z direction) of the current collector clad material 1 and on the other side (Z2 side). The negative electrode active material layer 3 is formed on the surface 1 b. And the clad material 1 for current collectors is comprised so that the electricity which generate | occur | produced from any one of the positive electrode active material layer 2 or the negative electrode active material layer 3 may be sent to the other. That is, the current collector clad material 1 is configured to function as the bipolar electrode 100 in the state where the positive electrode active material layer 2 and the negative electrode active material layer 3 are formed.

  The bipolar electrode 100 is configured to be used as an intermediate electrode of the secondary battery 101 as shown in FIG. Specifically, in the secondary battery 101, the plurality of bipolar electrodes 100 are stacked in the thickness direction via the solid electrolyte 104 made of a polymer, an oxide, or a sulfide. At this time, the bipolar electrodes 100 are arranged so that mutually different poles face each other in the thickness direction via the solid electrolyte 104. And while electricity (electric power) is taken out outside at the time of discharge from electrodes 105 and 106 arranged at the outermost layer, it is constituted so that electricity (electric power) may be supplied from the exterior at the time of charge. Thereby, since it is not necessary to connect electrodes using a bus-bar, it is possible to make an electrical loss small compared with the case where several battery cells are connected via a bus-bar.

  As shown in FIG. 1, the current collector clad material 1 is a foil-like member having a thickness t1 of about 100 μm or less. The thickness t1 of the current-collector clad material 1 is preferably about 50 μm or less because the thickness of the bipolar electrode 100 and the thickness of the secondary battery 101 using the same can be reduced. When the thickness t1 of the current collector clad material 1 is small, warpage is likely to occur, so that the effect of the present invention (effect of suppressing the occurrence of warpage) is further enhanced.

  In addition, the clad material 1 for current collector is joined to each other by rolling in a state where an Al layer 11 composed of an Al-based alloy and a Cu layer 12 composed of a Cu-based alloy are stacked in the thickness direction. It is done. That is, the current collector clad material 1 is formed of a two-layered clad material. The Al layer 11 is disposed on the surface 1a side on one side in the thickness direction (Z1 side, the positive electrode active material layer 2 side), and the Cu layer 12 is on the other side in the thickness direction (Z2 side, negative electrode active It is disposed on the surface 1 b side of the material layer 3 side).

  In addition, as an Al-based alloy constituting the Al layer 11, pure Al containing about 99 mass% or more of Al such as A1050, an Al-Mn alloy such as A3003, an Al-Mg alloy such as A5052, Al such as A6061 It is possible to use an Mg-Si alloy or the like. In addition, as a Cu-based alloy forming the Cu layer 12, pure Cu containing about 99 mass% or more of Cu such as C1020 (oxygen-free copper), a Cu-Fe alloy such as C1940, a Cu-Zr alloy, etc. are used It is possible.

In addition, the Al-based alloy forming the Al layer 11 has a smaller proof stress and is more likely to be plastically deformed than the Cu-based alloy forming the Cu layer 12. Also, the Al-based alloy has a larger electrical resistance than the Cu-based alloy. Specifically, the electrical resistivity at 20 ° C. of A1050 as an example of an Al-based alloy is about 28 nΩ · m, and the electrical resistivity at 20 ° C. of C1020 as an example of a Cu-based alloy is about 17 nΩ · m It is. Furthermore, the Al-based alloy has a larger thermal expansion coefficient than the Cu-based alloy. Specifically, the thermal expansion coefficient of A1050 as an example of an Al-based alloy is about 23 × 10 ^-6 / K, and the thermal expansion coefficient of C1020 as an example of a Cu-based alloy is about 17 × 10 ^-6 It is / K.

  Here, in the reference example, the ratio of the thickness t2 of the Al layer 11 to the total thickness (the thickness t1 of the clad material 1 for current collector) of the thickness t2 of the Al layer 11 and the thickness t3 of the Cu layer 12 is 35% It is formed to be as follows. As a result, as described later, it is possible to suppress the occurrence of warpage in the current collector clad material 1. Further, since the thickness t3 of the Cu layer 12 formed of a Cu-based alloy having a small electric resistance can be increased, the electric resistance of the current collector clad material 1 can also be reduced. The ratio of the thickness t2 of the Al layer 11 is more preferably about 25% or less.

  Next, with reference to FIG. 1, a manufacturing process of the current collector clad material 1 in the reference example will be described.

  First, a long Al plate (not shown) composed of an Al-based alloy and a long Cu plate (not shown) composed of a Cu-based alloy are prepared. The Al plate and the Cu plate are both annealed. Under the present circumstances, after rolling, thickness t2 (refer FIG. 1) of Al layer 11 with respect to total thickness (thickness t 1 of clad material 1 for current collectors) of thickness t 2 of Al layer 11 and thickness t 3 of Cu layer 12 The thickness of the Al plate and the thickness of the Cu plate are adjusted so that the ratio is 35% or less.

  Then, in a state in which the long Al plate material and the Cu plate material are stacked in the thickness direction (Z direction), rolling is performed at a predetermined rolling reduction along the extending direction of the Al plate material and the Cu plate material. Thereafter, the rolled material is diffusion annealed at about 500.degree. As a result, a strong bond is formed at the interface between the Al plate and the Cu plate by atomic diffusion, compound formation, or the like, and a clad material in which an Al layer and a Cu layer are joined is formed. Then, the clad material is cold rolled to a thickness t1 of about 100 μm or less. Thereby, as shown in FIG. 1, the elongate collector material 1 for current collectors which has thickness t1 to which Al layer 11 and Cu layer 12 were joined is manufactured. During the cold rolling, residual stress due to plastic deformation is generated in the Al layer 11 and the Cu layer 12.

  Here, at the time of rolling, since the Al-based alloy is more easily plastically deformed than the Cu-based alloy, the Al layer 11 is extended than the Cu layer 12. However, in the current collector clad material 1 of the reference example, when the thickness ratio of the Al layer 11 after rolling is 35% or less, the influence of the warpage due to the Al-based alloy is reduced at the time of rolling. Thereby, it is suppressed that the Al layer 11 side (Z1 side) of the clad material 1 for current collectors becomes convex in both the width direction (X direction) and the longitudinal direction (Y direction).

  Next, with reference to FIGS. 1 and 2, a manufacturing process of the secondary battery 101 in the reference example will be described.

  First, a slurry in which a positive electrode active material, a binder and a solvent are mixed is applied on the surface 1a of the long current collector clad material 1 on the Al layer 11 side (Z1 side, see FIG. 1). Here, since a tension is applied to the long current collector clad material 1 in the longitudinal direction (Y direction) at the time of slurry application, the warp in the longitudinal direction is corrected to some extent. Therefore, when the slurry is applied to the long current collector clad material 1 in this manner, the influence of the warpage in the width direction (X direction) of the current collector clad material 1 is due to the influence of the warpage in the longitudinal direction. In particular, it is preferable to sufficiently reduce the warpage in the width direction, which has a large influence on the slurry application. On the other hand, when the slurry is applied to the current collector clad material 1 cut in advance, it is considered that not only the influence of the warpage in the width direction of the current collector clad material 1 but also the influence of the warp in the longitudinal direction becomes large. Therefore, it is necessary to make the warpage in both the width direction and the longitudinal direction sufficiently small. In addition, in the clad material 1 for current collectors of the reference example, since generation of warpage in both the width direction and the longitudinal direction is suppressed, the slurry is uniformly applied on the surface 1a of the clad material 1 for current collectors. It is possible.

  Thereafter, the slurry is dried by heat treatment at a predetermined temperature (about 150 ° C.). During the heat treatment, the Al-based alloy forming the Al layer 11 is annealed to remove residual stress generated during cold rolling. As a result, the convex warpage on the Al layer 11 side of the collector material for current collector 1 is reduced.

  Then, after the heat treatment, the current collector clad material 1 is cooled to room temperature. Thereby, as shown in FIG. 1, the positive electrode active material layer 2 is formed on the surface 1a. During this cooling, the Al layer 11 contracts more than the Cu layer 12 due to the difference in thermal contraction between the Al-based alloy and the Cu-based alloy. However, when the thickness ratio of the Al layer 11 is 35% or less, the influence of the warpage due to the large thermal contraction of the Al-based alloy is reduced at the time of cooling after the heat treatment. Thereby, it is suppressed that the Al layer 11 side (Z1 side) of the clad material 1 for current collectors becomes concave.

  Further, as in the case of the positive electrode active material layer 2, a slurry in which a negative electrode active material, a binder and a solvent are mixed is applied on the surface 1b on the Cu layer 12 side (Z2 side), and heat treatment and cooling are performed. The negative electrode active material layer 3 is formed on 1b. The positive electrode active material layer 2 and the negative electrode active material layer 3 may be simultaneously formed on different surfaces 1 a and 1 b of the current-collector clad material 1. Thus, a long bipolar electrode 100 is manufactured. Thereafter, the long bipolar electrode 100 is cut into a predetermined size. The cutting of the long bipolar electrode 100 (cladding material 1 for current collector) may be performed before applying the slurry to the cladding material 1 for current collector.

  Finally, a plurality of bipolar electrodes 100 and a solid electrolyte 104 composed of a polymer, an oxide, or a sulfide are alternately stacked, and the electrode 105 is disposed on the outermost layer on the Z1 side, and the outermost layer on the Z2 side The electrode 106 is placed. Thereby, the secondary battery 101 shown in FIG. 2 is manufactured.

  In the reference example, the following effects can be obtained.

  In the reference example, as described above, in the current collector clad material 1 having a two-layer structure joined by rolling, an Al layer 11 composed of an Al-based alloy and a Cu layer 12 composed of a Cu-based alloy The ratio of the thickness t2 of the Al layer 11 to the total thickness (t1) of the above is 35% or less. Thus, the ratio of the thickness t2 of the Al layer 11 made of an Al-based alloy which is easily plastically deformed is 35% or less, so that the influence of the warpage caused by the Al-based alloy can be reduced during rolling. As a result, it is possible to suppress large warpage so that the Al layer 11 side (Z1 side) of the collector material for current collector 1 is convex. In addition, since the influence of warpage due to the large thermal contraction of the Al-based alloy can be reduced even at the time of cooling after heat treatment, the side of the Al layer 11 of the clad material 1 for current collector is largely warped. Can be suppressed. As a result of these, it is possible to suppress the occurrence of large warpage in the current collector clad material 1.

  In the reference example, an Al layer 11 composed of a flexible Al-based alloy is disposed on the surface 1 a of the collector material for current collector 1, and a Cu layer 12 composed of a flexible Cu-based alloy is disposed on the surface 1 b. Do. As a result, when the positive electrode active material is disposed on the surface 1a, the positive electrode active material can be sufficiently adhered to the surface 1a by an Al-based alloy that is softer than conventional stainless steel. The contact area with the body cladding material 1 can be increased. In addition, when the negative electrode active material is disposed on the surface 1b, the negative electrode active material can be sufficiently adhered to the surface 1b by a Cu-based alloy that is more flexible than conventional stainless steel. The contact area with the cladding material 1 can be increased. As a result, the contact resistance between the current collector clad material 1 and the active material (positive electrode active material and negative electrode active material) is increased compared to the case where the current collector clad material is made of a hard metal material such as SUS. Can be suppressed.

  Further, in the reference example, in the current collector clad material 1 having a thickness t1 of about 100 μm or less and being susceptible to warpage, the ratio of the thickness t2 of the Al layer 11 is 35% or less. It can suppress that a big curvature arises in material 1.

  Further, in the reference example, the current collector is configured by arranging the current collector clad material 1 such that the positive electrode active material layer 2 is disposed on the surface 1 a and the negative electrode active material layer 3 is disposed on the surface 1 b. The clad material 1 can be formed into a bipolar electrode 100 in which the positive electrode active material layer 2 and the negative electrode active material layer 3 are formed on different surfaces 1a and 1b, respectively. In addition, at the time of cooling after the heat treatment at the time of forming the positive electrode active material layer 2 and the negative electrode active material layer 3, it is possible to suppress the occurrence of large warpage in the current collector clad material 1 (bipolar electrode 100).

  Next, a reference example will be described with reference to FIGS. 1 and 3 to 5.

  In the reference example, a plurality of current collector clad materials having a two-layer structure in which the thickness ratio between the Al layer and the Cu layer is made different are manufactured. And the curvature of the width direction of the clad material for current collectors and the curvature of a longitudinal direction after rolling were measured. Moreover, the curvature of the width direction of the clad material for current collectors after heat treatment and cooling of the clad material for current collectors (after heat treatment) was measured.

  Here, a clad material 1 for a current collector (see FIG. 1) of Reference Example 1 of the reference example was manufactured along the manufacturing process of the above reference example. Specifically, first, a long Al plate material made of A1050 (pure Al) and a long Cu plate material made of C1020 (pure Cu) were prepared. The Al plate and the Cu plate are both annealed. At this time, the thickness of the Al plate and the thickness of the Cu plate were adjusted such that the ratio of the thickness of the Al plate to the total thickness of the thickness of the Al plate and the thickness of the Cu plate was 20%.

  Then, in a state in which the long Al plate material and the Cu plate material are stacked in the thickness direction (Z direction), rolling is performed at a reduction ratio of 50% along the extending direction of the Al plate material and the Cu plate material. Thereafter, the rolled material was diffusion annealed at 500 ° C. Then, the clad material was cold-rolled so as to have a thickness t1 of 50 μm, whereby a long clad material 1 for current collector was produced. Finally, the long collector clad material 1 is cut into a width W of 40 mm in the width direction (X direction) (see FIG. 4) and a length L of 100 mm in the longitudinal direction (Y direction) (see FIG. 4) Cut into a rectangular shape.

  Thus, the ratio of the thickness t2 of the Al layer 11 to the total thickness of the thickness t2 of the Al layer 11 and the thickness t3 of the Cu layer 12 (the thickness t1 of the clad material 1 for current collector) is 20%. A clad material 1 for a current collector was produced.

  Further, a collector material 1 for a current collector of Reference Example 2 was produced in the same manner as in Reference Example 1 except that the ratio of the thickness t2 of the Al layer 11 was 30%. Further, in the same manner as in Example 1 except that the ratio of the thickness t2 of the Al layer 11 was 40%, a clad material for a current collector of Comparative Example 1 was produced. Further, in the same manner as in Example 1 except that the ratio of the thickness t2 of the Al layer 11 was 50%, a clad material for a current collector of Comparative Example 2 was produced.

  Then, in the clad materials for current collectors of Reference Examples 1 and 2 and Comparative Examples 1 and 2, warpage in the width direction (X direction) after rolling and warpage in the longitudinal direction (Y direction) were measured.

  Specifically, in the measurement of warpage in the width direction, as shown in FIG. 3, a rectangular collector clad material for a current collector was placed on a horizontal surface plate 7 as a reference of the plane. Then, in order to correct the warp in the longitudinal direction, the four corners of the rectangular collector clad material were fixed (open arrows) using a jig not shown. In addition, fixation was performed as close to pinpoint as possible. In that state, displacement in the thickness direction (Z direction) along the width direction was measured by scanning the laser beam in the width direction using a general laser displacement meter. Then, the warp in the longitudinal direction of the side 1c extending in the longitudinal direction (Y direction) was corrected to obtain the maximum displacement amount when the displacement amount was set to 0 (zero) as the warp in the width direction.

  Further, in the measurement of warpage in the longitudinal direction, as shown in FIG. 4, a rectangular collector material for a current collector was disposed on the surface plate 7. And the displacement of the thickness direction along a longitudinal direction was measured by scanning a laser beam to a longitudinal direction in the state which does not fix with a jig. Then, the maximum displacement amount was obtained as the warp in the longitudinal direction.

  Further, heat treatment was performed by holding the clad materials for current collectors of Reference Examples 1 and 2 and Comparative Examples 1 and 2 in a drier under a temperature environment of 150 ° C. for 30 minutes. And after cooling the clad material for current collectors to room temperature, it carried out similarly to the measurement of the width direction after the said rolling, and measured the curvature of the width direction after heat processing.

  In addition, about curvature, when it bends so that Al layer 11 side (Z1 side, see FIG. 1) may become convex, it is set as positive (+), and when it warps so that Al layer 11 side may become concave. , Negative (-) described in FIG. That is, regardless of positive or negative, when the warpage is close to 0 (when the absolute value is small), the warpage of the current collector clad material decreases and as the warpage moves away from 0 (the absolute value increases) Warpage of the body cladding material is increased.

  As a result of the reference example shown in FIG. 5, in any of the current collector clad materials 1 of Reference Examples 1 and 2, the warpage was smaller than that of the current collector clad materials of Comparative Examples 1 and 2. Specifically, after rolling, the warpage in the width direction (X direction) and the warpage in the longitudinal direction (Y direction) of the clad material 1 for current collectors of Reference Examples 1 and 2 are both convex on the Al layer 11 side, It became 1.2 mm or less and 7.0 mm or less, respectively. On the other hand, after rolling, the warpage in the width direction of the clad material for current collectors of Comparative Examples 1 and 2 is convex on the Al layer 11 side and becomes larger than 1.2 mm, and the warpage in the longitudinal direction is the aluminum layer 11 side It is convex and larger than 7.0 mm. Thereby, in the clad material 1 for current collectors of the reference examples 1 and 2, it was confirmed that generation | occurrence | production of curvature could fully be suppressed after rolling. Since the thickness t2 of the Al layer 11 made of A1050 (Al-based alloy) which is easily plastically deformed is sufficiently smaller than the thickness t3 of the Cu layer 12, this reduces the influence of warpage caused by the A1050 during rolling. It is thought that it is because it was possible.

  Further, even after the heat treatment, the warpage in the width direction of the collector material 1 for a current collector of Reference Examples 1 and 2 was concaved to 1.4 mm or less on the Al layer 11 side. On the other hand, after the heat treatment, the warpage in the width direction of the current collector clad materials of Comparative Examples 1 and 2 was concave on the Al layer 11 side and became larger than 1.4 mm. As a result, it was confirmed that the occurrence of warpage can be sufficiently suppressed in the clad material 1 for current collector of Reference Examples 1 and 2 even after the heat treatment. In addition, the residual stress which arose at the time of cold rolling is removed by annealing A1050 which comprises Al layer 11 at the time of heat processing. By cooling to room temperature in a state where the residual stress is removed and the convex warpage on the Al layer 11 side of the current-collector clad material 1 is reduced, the Al layer 11 with a large amount of thermal contraction is greatly shrunk. However, when thickness t2 of Al layer 11 made of A1050 which is easily plastically deformed is sufficiently smaller than thickness t3 of Cu layer 12, it is considered that generation of concave warpage on the side of Al layer 11 could be suppressed. .

  As a result, as in Reference Examples 1 and 2, the thickness t2 of the Al layer 11 with respect to the total thickness of the thickness t2 of the Al layer 11 and the thickness t3 of the Cu layer 12 (thickness t1 of the clad material 1 for current collector) By setting the ratio to 35% or less, it is confirmed that warpage can be sufficiently suppressed as compared with the case where the ratio of the thickness t2 of the Al layer 11 is larger than 35% as in Comparative Examples 1 and 2. did it. In addition, in order to effectively suppress the warpage, it was also confirmed that it is better to set the ratio of the thickness t2 of the Al layer 11 to 25% or less (20%) as in Reference Example 1.

  In addition, the warpage in the width direction is about 31% (= (0.4 / 1.3) x 100) smaller than that in Comparative Example 1 in Reference Example 2, and the warpage in the longitudinal direction is about 27% ( It became small to = (1.9 / 7.1) x 100). Therefore, in particular, in the clad material 1 for current collectors of Reference Examples 1 and 2, the warpage in the width direction and the warpage in the longitudinal direction after rolling are significantly suppressed more than in the clad materials for current collectors of Comparative Examples 1 and 2. I could confirm that I could do it.

  In addition, it was found that as the ratio of the thickness t2 of the Al layer 11 is reduced, the warpage after rolling and after the heat treatment becomes smaller. Thus, it is considered preferable that the thickness t2 of the Al layer 11 be as small as possible. On the other hand, reducing the thickness of the Al layer 11 (for example, to about 1 μm or less) to the extent that breakage occurs in the Al layer 11 in the manufacturing process is considered to be undesirable for manufacturing.

  In the reference example, although A1050 is used as the Al-based alloy forming the Al layer 11 and C1020 is used as the Cu-based alloy forming the Cu layer 12, the Al-Mn alloy, the Al-Mg alloy and the Al-based alloy are used. Even when using an Al alloy such as an Al-Mg-Si alloy or using a Cu alloy such as a Cu-Fe alloy or a Cu-Zr alloy as the Cu-based alloy, the ratio t of the thickness t2 of the Al layer 11 is 35 It is thought that it is possible to suppress the curvature of the clad material for current collectors similarly to the reference examples 1 and 2 by making it% or less.

(Embodiment)
Next, an embodiment of the present invention will be described with reference to FIG. In this embodiment, unlike the reference example, an example in which a core material layer 213 having a Young's modulus of 150 GPa or more is provided between the Al layer 211 and the Cu layer 212 will be described. The Al layer 211 and the Cu layer 212 are examples of the “first layer” and the “second layer” in the present invention respectively.

  As shown in FIG. 6, the current collector clad material 201 in this embodiment is configured to function as a bipolar electrode 200 in a state in which the positive electrode active material layer 2 and the negative electrode active material layer 3 are formed. There is. Further, the current collector clad material 201 is a foil-like member having a thickness t1a of about 100 μm or less. The current collector clad material 201 is an example of the “battery current collector clad material” in the present invention, and the bipolar electrode 200 is an example of the “electrode” in the present invention.

  Here, in the present embodiment, the current collector clad material 201 includes the Al layer 211 made of an Al-based alloy, the Cu layer 212 made of a Cu-based alloy, and the Al layer 211 and the Cu layer 212. The core layers 213 disposed between the layers are joined together by rolling in a state where they are joined in the thickness direction (Z direction). That is, the current collector clad material 201 is formed of a three-layered clad material. The Al layer 211 is exposed on the surface 1a side on the Z1 side, and the Cu layer 212 is exposed on the surface 1b side on the Z2 side.

  The core layer 213 is made of a Ni-based alloy or Fe-based alloy having a Young's modulus of 150 GPa or more, and compared with the Al-based alloy forming the Al layer 211 and the Cu-based alloy forming the Cu layer 212. Young's modulus is high. Further, the Ni-based alloy or the Fe-based alloy constituting the core layer 213 has a larger proof stress than the Al-based alloy constituting the Al layer 211 and the Cu-based alloy constituting the Cu layer 212. That is, since the core material layer 213 has both the proof stress and the Young's modulus larger than that of the Al layer 211 and the Cu layer 212, it is difficult for plastic deformation and elastic deformation.

  In addition, as Ni base alloys, pure Ni containing about 99 mass% or more Ni, such as NW2200 (normal carbon nickel, refer to JISH4551), and about 3 mass% or more and about 7 mass% of Nb, Ni and unavoidable It is possible to use a Ni alloy such as a Ni-Nb alloy composed of an impurity element. Further, as the Fe-based alloy, it is possible to use a low carbon steel (pure Fe) containing about 99% by mass or more of Fe, or a stainless steel such as SUS340. The core layer 213 may be a metal material having a Young's modulus of about 150 GPa or more. In addition, the Young's modulus of NW 2200 as an example of the Ni-based alloy is about 195 GPa.

Also, the Ni-based alloy has a smaller thermal expansion coefficient than the Al-based alloy and the Cu-based alloy. Specifically, the thermal expansion coefficient of NW 2200 as an example of a Ni-based alloy is about 13 × 10 ⁻⁶ / K.

  In the present embodiment, the ratio of the thickness t2a of the Al layer 11 to the total thickness (= t2a + t3a) of the thickness t2a of the Al layer 211 and the thickness t3a of the Cu layer 212 is 60% or less. There is. The ratio of the thickness t2a of the Al layer 11 is more preferably about 50% or less.

  The thickness t4 of the core member 204 is configured to be about 30% or more and about 80% or less of the thickness t1a (= t2a + t3a + t4) of the current-collector clad material 201. The remaining structure of the present embodiment is similar to that of the aforementioned reference example.

  Next, with reference to FIG. 6, a manufacturing process of the current collector clad material 201 in the present embodiment will be described.

  First, a long Al plate material (not shown) composed of an Al-based alloy, a long Cu plate material (not shown) composed of a Cu-based alloy, a Ni-based alloy having a Young's modulus of 150 GPa or more or A long plate-like core (not shown) composed of an Fe-based alloy is prepared. In addition, Al board material, Cu board material, and a core material are annealed together. At this time, after rolling, the ratio of the thickness t2a of the Al layer 11 to the total thickness (= t2a + t3a) of the thickness t2a of the Al layer 211 and the thickness t3a of the Cu layer 212 becomes 60% or less. The thickness of each plate is adjusted so that the thickness t4 of the plate is about 30% or more and about 80% or less of the thickness t1a (= t2a + t3a + t4) of the current-collector clad material 201 (see FIG. 6).

  Then, in a state in which the long Al plate material, the core material and the Cu plate material are stacked in the thickness direction (Z direction), rolling is performed at a predetermined reduction ratio along the extending direction of the Al plate material, the core material and the Cu plate material. Then, the rolled material is diffusion annealed at a predetermined temperature. Thus, a clad material in which the Al layer, the core layer and the Cu layer are joined is formed. Thereafter, the clad material is cold rolled to a thickness t1a of about 100 μm or less. Thereby, as shown in FIG. 6, the clad material 201 for current collector having a thickness t1a is formed by bonding the Al layer 211, the core layer 213 and the Cu layer 212 in this order in the thickness direction (Z direction). Manufactured. Here, at the time of rolling, the core layer 213 having a high Young's modulus and contributing to the improvement of the rigidity of the current collector clad material 201 reduces the influence of the warpage caused by the Al-based alloy at the time of rolling. Thereby, it is suppressed that the Al layer 211 side (Z1 side) of the clad material 201 for current collectors becomes convex.

  In addition, the manufacturing process of the battery in this embodiment is the same as that of the said reference example. That is, by removing the residual stress of the Al-based alloy generated at the time of cold rolling in the heat treatment, the convex warpage on the Al layer 211 side of the collector material for current collector 201 is reduced. Then, at the time of cooling after the heat treatment, the core layer 213 having a high Young's modulus and a small thermal expansion coefficient suppresses the contraction of the Al layer 211, whereby the Al layer of the current collector clad material 201 is obtained. Warping is suppressed so that the side 211 becomes concave.

  In the present embodiment, the following effects can be obtained.

  In the present embodiment, as described above, the core layer 213 having a Young's modulus of 150 GPa or more is disposed between the Al layer 211 and the Cu layer 212 of the current-collector clad material 201. Thus, even when the thickness ratio of the Al layer 211 made of an Al-based alloy which is easily plastically deformed is relatively large at 60% or less, the Young's modulus is high, which contributes to the improvement of the rigidity of the current collector clad material 201. Due to the core layer 213, it is possible to reduce the influence of the warpage caused by the Al-based alloy at the time of rolling. As a result, it is possible to suppress large warpage so that the Al layer 211 side (Z1 side) of the collector material for current collector 201 is convex. In addition, even at the time of cooling after heat treatment, the core layer 213 having a high Young's modulus and contributing to the improvement of the rigidity of the current collector clad material 201 reduces the influence of the warpage caused by the large thermal contraction of the Al-based alloy. As a result, it is possible to suppress large warpage so that the Al layer 211 side of the current-collector clad material 201 becomes concave. As a result of these, it is possible to suppress the occurrence of large warpage in the current collector clad material 201.

  Further, in the present embodiment, an Al layer 211 made of an Al-based alloy that is softer than conventional stainless steel is disposed on the surface 1a of the current collector clad material 201, and Cu that is softer than conventional stainless steel on the surface 1b. By arranging the Cu layer 212 composed of the base alloy, the contact resistance between the current collector clad material 201 and the active material (positive electrode active material and negative electrode active material) is increased as in the first embodiment. Can be suppressed. Furthermore, by providing the soft Al layer 211 and the Cu layer 212, it is possible to suppress the reduction of the rolling processability as compared with the case where the current collector material is made of only a hard single stainless steel plate. As a result, the current collector clad material 201 can be manufactured efficiently, and the cost of rolling can be reduced.

  Further, in the present embodiment, the core layer 213 having a high Young's modulus between the Al layer 211 and the Cu layer 212 of the current collector clad material 201 and contributing to the improvement of the rigidity of the current collector clad material 201. Is used to suppress the occurrence of deformation such as wrinkles in the current collector clad material 201 due to repeated expansion and contraction of the active material due to charge and discharge when used in a secondary battery. be able to. As a result, the active material (the positive electrode active material and the negative electrode active material) comes off from the surfaces 1a and 1b of the current collector clad material 201, and the contact between the current collector clad material 201 and the active material occurs. An increase in resistance can be suppressed. As a result, the clad material for current collector 201 can be more suitably used for a Si-based active material or the like that has large expansion and contraction due to charge and discharge.

  Further, in the present embodiment, by forming the core layer 213 from a Ni-based alloy or an Fe-based alloy, the ionization tendency of Ni and Fe is both between Al and Cu, so the core layer 213 is mainly used. The difference in ionization tendency between the constituent metal element (Ni or Fe) and the Al mainly constituting the Al layer 211, and the metal element mainly constituting the core layer 213 and Cu mainly constituting the Cu layer 212 Both the difference in ionization tendency can be reduced. Thus, it is possible to suppress the occurrence of corrosion between the core layer 213 made of a Ni-based alloy or an Fe-based alloy and the Al layer 211 made of an Al-based alloy. The occurrence of corrosion between the base alloy and the Cu layer 212 can be suppressed. In addition, by using a Ni-based alloy or an Fe-based alloy as the core layer 213, it is possible to easily obtain the inexpensive core layer 213 having a Young's modulus of 150 GPa or more.

  In the present embodiment, if the core layer 213 is composed of pure Ni or a Ni-based alloy that is a Ni-Nb alloy containing Nb, the Ni-Nb alloy containing pure Ni or Nb has a high Young's modulus. Therefore, the present invention can sufficiently contribute to the improvement of the rigidity of the current collector clad material 201. Therefore, the occurrence of a large warpage in the current collector clad material 201 can be further suppressed.

  Further, in the present embodiment, the thickness t4 of the core layer 213 is sufficiently secured by setting the thickness t4 of the core layer 213 to about 30% or more of the thickness t1a of the clad material 201 for current collector. The occurrence of a large warpage in the current collector clad material 201 can be reliably suppressed. Further, by setting the thickness t4 of the core layer 213 to about 80% or less of the thickness t1a of the clad material 201 for current collector, it is suppressed that the thickness t4 of the core layer 213 having a high Young's modulus becomes excessively large. While being able to do, it can control that thickness t2a of Al layer 211 and thickness t3a of Cu layer 212 become small. Accordingly, it is possible to suppress the occurrence of breakage in the small-thickness Al layer 211 and the Cu layer 212 due to an increase in pressure required to roll the core layer 213 having a large thickness t4. Thereby, the clad material 201 for current collectors can be manufactured efficiently.

  Further, in the present embodiment, in the clad material 201 for current collector, the thickness t1a is about 100 μm or less and warpage is generally caused and the ratio of the thickness t2a of the Al layer 211 is 60% or less. By providing the core layer 213 having a Young's modulus, it is possible to suppress the occurrence of large warpage in the current collector clad material 201. The remaining effects of the present embodiment are similar to those of the aforementioned reference example.

(Example)
Next, with reference to FIG. 4 and FIG. 6 to FIG. 7, an embodiment carried out to confirm the effect of the present invention will be described.

  In the example, the current collector clad material 201 of Example 11 having a three-layer structure of the Al layer 211, the core layer 213, and the Cu layer 212 was produced. And while measuring the curvature of the width direction of the clad material 201 for current collectors, and the curvature of a longitudinal direction at the time of rolling similarly to the above-mentioned reference example, the width direction of the clad material 201 for current collectors after heat treatment The warpage of was measured.

  Here, the current collector clad material 201 of the example 11 of the example was manufactured along the manufacturing process in the above embodiment. Specifically, first, a long Al plate material made of A1050 (pure Al), a long Cu plate material made of C1020 (pure Cu), and a long device made of NW2200 (pure Ni) A plate-like core material was prepared. In addition, Al board material, Cu board material, and a core material are annealed together. At this time, the ratio of the thickness of the Al plate to the total thickness of the thickness of the Al plate and the thickness of the Cu plate becomes 50%, and the core to the total of the thickness of the Al plate, the thickness of the Cu plate, and the thickness of the core material The thickness of each plate was adjusted so that the thickness of the material was 33%.

  Then, rolling and diffusion annealing were performed in the same manner as in the above reference example, in a state in which the long Al plate material, the core material, and the Cu plate material were laminated in the thickness direction (Z direction). Then, the clad material was cold-rolled so as to have a thickness t1a of 50 μm, whereby a long current collector clad material 201 was produced. Finally, the long current collector clad material 201 is cut into a rectangular shape (see FIG. 4) having a width W of 40 mm in the width direction (X direction) and a length L of 100 mm in the longitudinal direction (Y direction). did. Thus, the ratio of the thickness t2a of the Al layer 211 to the total thickness (= t2a + t3a) of the thickness t2a of the Al layer 211 and the thickness t3a of the Cu layer 212 is 50%, and the thickness t2a of the Al layer 211 and the Cu layer The clad material 201 for current collector of Example 11 in which the thickness t4 of the core layer 213 is 33% with respect to the total (= t1a) of the thickness t3a 212 and the thickness t4 of the core layer 213 is produced.

  And in the clad material 201 for current collectors of Example 11, while measuring the curvature of the width direction (X direction) after rolling and the curvature of a longitudinal direction (Y direction) similarly to the said reference example, heat processing are carried out Warpage in the width direction was measured. As for the warpage, as in the above reference example, when the Al layer 211 (see FIG. 6) is warped so as to be convex, it is positive (+) and the Al layer 211 is warped so as to be concave. In the case, it described in FIG. 7 as negative (-).

  As a result of the embodiment shown in FIG. 7, both the warpage in the width direction (X direction) and the warpage in the longitudinal direction (Y direction) of the clad material 201 for a current collector of Example 11 after the rolling are Al layers 211. The side was convex, and became 1.2 mm or less and 7.0 mm or less, respectively. Thereby, in the clad material 201 for current collectors of Example 11, it was confirmed that generation | occurrence | production of curvature could fully be suppressed after rolling. Although this is relatively large at 50% of the ratio t2a of the thickness t2a of the Al layer 211 made of A1050 (Al-based alloy) which is easily plastically deformed, the core layer 213 made of NW2200 having a high Young's modulus of 195 GPa It is considered that the influence of warpage caused by A1050 could be reduced during rolling.

  In addition, even after the heat treatment, the warpage in the width direction of the current collector clad material 201 of Example 11 was concaved to 1.4 mm or less on the Al layer 211 side. As a result, it was confirmed that the occurrence of warpage can be sufficiently suppressed in the current collector clad material 201 of Example 11 even after the heat treatment. In addition, since it was able to suppress that the Young's modulus is high and contributes to the improvement of the rigidity of the clad material 201 for current collectors, the large shrinkage of the Al layer 211 having a large amount of thermal contraction can be suppressed. It is considered to be.

  As a result, even when the ratio of the thickness t2a of the Al layer 211 to the total thickness of the thickness t2a of the Al layer 211 and the thickness t3a of the Cu layer 212 is 60% or less as in Example 11, It has been confirmed that warpage can be sufficiently suppressed by providing the core layer 213 having a Young's modulus of 150 GPa or more.

  Furthermore, even if Comparative Example 2 of FIG. 5 and Example 11 of FIG. 7 in which the ratio of the thickness of the Al layer is 50% are compared with each other, the core material layer 213 In Example 11 provided, it was confirmed that the occurrence of warpage is further suppressed. Moreover, it turned out that especially the curvature of the longitudinal direction after rolling becomes small to about 5% (= (0.5 / 10. 1) x 100) notably.

  In Example 11 of the embodiment, although NW2200 is used as the metal material for forming the core layer 213, a Ni alloy such as a Ni-Nb alloy having a Young's modulus of 150 GPa or more, Fe such as pure Fe, stainless steel, etc. Even when an alloy or the like is used as the core layer 213, if the thickness ratio of the Al layer 211 is 60% or less, warpage of the current collector clad material 201 can be suppressed as in Example 11. It is considered to be.

  In addition, in Example 11 of the example, although the ratio of the thickness t2a of the Al layer 211 is set to 50%, the ratio of the thickness t2a of the Al layer 211 is set to a size other than 50% and 60% or less. Also in this case, if the Young's modulus of the core layer 213 is 150 GPa or more, it is considered that warpage of the current collector clad material 201 can be suppressed as in Example 11.

  Further, in Example 11 of the example, although the thickness t4 of the core layer 213 is 33% of the thickness t1a of the clad material 201 for current collector, the thickness t4 of the core layer 213 is other than 33% and When the thickness t2a of the Al layer 211 is 60% or less even when the size is in the range of about 30% or more and about 80% or less, as in Example 11, the clad material 201 for current collector is used. It is believed that warpage can be reliably suppressed.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the description of the embodiments and examples described above but by the claims, and further includes all modifications (variations) within the meaning and scope equivalent to the claims.

  For example, although the example which the core material layer 213 consists of 1 layer was shown in the said embodiment, this invention is not limited to this. In the present invention, the core layer may be composed of a plurality of layers. Under the present circumstances, it is good to laminate in order so that an ionization tendency may become small toward the 2nd layer comprised from Cu base alloy from the 1st layer comprised from Al base alloy. This makes it possible to effectively suppress the occurrence of corrosion in the current collector clad material. When the core layer is formed of a plurality of layers, the Young's modulus needs to be 150 GPa or more in the entire core layer, and the thickness of the entire core layer is about 30 of the thickness of the current collector clad material. % Or more and about 80% or less.

  Moreover, although the example which used the clad material 201 for collectors as the bipolar type electrode 200 was shown in the said embodiment, this invention is not limited to this. In the present invention, the current collector clad material may be used as a monopolar electrode in which only one of the positive electrode active material layer and the negative electrode active material layer is formed.

  Moreover, although the example which comprises the core material layer 213 from Ni-based alloy or Fe-based alloy whose Young's modulus is 150 GPa or more was shown in the said embodiment, this invention is not limited to this. In the present invention, the core layer may be a metal material having a Young's modulus of 150 GPa or more, and may be made of a metal material other than Ni-based alloy or Fe-based alloy.

  Moreover, although the example which used the solid electrolyte 104 in the secondary battery 101 was shown in the said embodiment, this invention is not limited to this. In the present invention, a liquid electrolyte (electrolyte solution) may be used instead of the solid electrolyte. In this case, it is necessary to dispose the electrolytic solution between the bipolar electrodes and to separate adjacent electrolytic solutions so as not to short circuit each other.

201 Cladding material for current collector (cladding material for battery current collector)
1a surface (one surface)
1b surface (other surface)
2 Positive electrode active material layer 3 Negative electrode active material layer 211 Al layer (first layer)
212 Cu layer (second layer)
200 bipolar electrodes (electrodes)
213 core layer

Claims (5)

A first layer arranged on one surface and made of an Al-based alloy, and a second layer arranged on the other surface and made of a Cu-based alloy, arranged between the first layer and the second layer And a core material layer having a Young's modulus of 150 GPa or more is made of a clad material joined by rolling,
The ratio of the thickness of the first layer to the total thickness of the first layer and the second layer is 50% or less, and the thickness of the core material layer is one third of the thickness of the cladding material. There is a clad material for battery current collector.   The battery current collector clad material according to claim 1, wherein the core material layer is made of a Ni-based alloy or an Fe-based alloy.   The clad material for a battery current collector according to claim 2, wherein the core layer is made of the Ni-based alloy which is pure Ni or a Ni-Nb alloy containing Nb.   The clad material for battery current collectors according to any one of claims 1 to 3, wherein a thickness of the clad material is 100 m or less.   An electrode, wherein a positive electrode active material layer is disposed on the one surface of the clad material for a battery current collector according to any one of claims 1 to 4, and a negative electrode active material layer is disposed on the other surface. .

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