CN115706232A - Negative electrode current collector and battery - Google Patents

Abstract

The invention relates to a negative electrode collector and battery. The negative electrode current collector of a battery using an electrolytic solution has: a base layer containing a metal having conductivity as a main component; a barrier layer laminated on the base layer and containing a transition metal as a main component; an alloy layer, the alloy layer is stacked on the barrier layer, and is obtained by alloying the transition metal with tin; the plating layer, the coating layer is stacked on the alloy layer, and uses tin as the main component, and the alloy layer is formed by the barrier layer It is obtained by alloying the transition metal of the layer with the tin of the plating layer.

Description

Negative current collector and battery

technical field

The present disclosure relates to technologies of negative electrode current collectors and batteries.

Background technique

Conventionally, for negative electrode current collectors, the following technology is known: a base layer mainly composed of copper and a plating layer formed on the base layer and containing tin as a main component are fired to form a gap between the base layer and the plating layer. An alloy layer is formed (Japanese Patent Application Laid-Open No. 2010-541183). In this technique, the alloy layer is a compound composed of copper and tin.

Contents of the invention

In a battery having a negative electrode including a negative electrode current collector and a negative electrode active material disposed around the negative electrode current collector, hydrogen may be generated in the negative electrode when an aqueous electrolyte solution is used. In this case, since the generated hydrogen adheres to the outer surface of the negative electrode, the function of the battery may be degraded. Therefore, there is a need for a technique for suppressing the generation of hydrogen in the anode having the anode current collector to attach hydrogen at the outer surface of the anode.

The present disclosure can be realized in the following manner.

(1) According to one aspect of the present disclosure, a negative electrode current collector of a battery using an electrolytic solution is provided. The negative electrode current collector has: a base layer, the base layer has a conductive metal as a main component; a barrier layer, the barrier layer is laminated on the base layer, and has a transition metal as a main component; an alloy layer, the the alloy layer laminated on the barrier layer and obtained by alloying the transition metal with tin; and a plating layer laminated on the alloy layer and containing the tin as a main component. According to this aspect, the negative electrode current collector has a barrier layer mainly composed of a transition metal, an alloy layer obtained by alloying a transition metal with tin, and a plating layer mainly composed of tin. Accordingly, generation of hydrogen in the negative electrode having the negative electrode current collector can be suppressed, and thus hydrogen can be suppressed from adhering to the outer surface of the negative electrode. In addition, when hydrogen is generated in the negative electrode, the hydrogen can be retained in layers such as an alloy layer located inside the outer surface of the negative electrode current collector. Therefore, it is possible to suppress hydrogen from adhering to the outer surface of the negative electrode. Therefore, it is possible to suppress hydrogen from being generated in the negative electrode having the negative electrode current collector and adhering to the outer surface of the negative electrode to cause a decrease in the function of the battery.

(2) In the above form, the electrolytic solution may be an alkaline aqueous electrolytic solution. According to this aspect, since the electrolytic solution is alkaline, more hydroxide ions exist in the electrolytic solution than when an acidic or neutral electrolytic solution is used. Electrons generated by the reaction between the hydroxide ions and the negative electrode active material flow to the positive electrode side, thereby realizing the discharge function of the battery. On the other hand, it may happen that electrons generated by the reaction of hydroxide ions with the negative electrode active material do not flow to the positive electrode side, but contribute to the reduction reaction of water in the electrolyte, whereby the water in the electrolyte is oxidized And hydrogen is generated in the negative electrode. Even in this case, by providing the negative electrode current collector with a barrier layer, an alloy layer, and a plating layer, generated hydrogen can be retained in layers such as the alloy layer located inside the outer surface of the negative electrode current collector. Therefore, generation of hydrogen in the negative electrode can be suppressed.

(3) In the above mode, the transition metal may be at least one of nickel, iron, chromium, zirconium and lanthanum. According to this aspect, when hydrogen is generated in the negative electrode, the barrier layer can be formed by the transition metal whose exchange current density involved in the hydrogen evolution reaction is smaller than that of gold. Therefore, in this mode, the hydrogen evolution reaction in the negative electrode is less likely to occur as compared with the case where the barrier layer is formed by a transition metal having a higher exchange current density involved in the hydrogen evolution reaction than gold. That is, the barrier layer can be formed by a transition metal capable of suppressing generation of hydrogen in the negative electrode.

(4) In the above aspect, the barrier layer may have a thickness of not less than 2 μm and not more than 10 μm. According to this aspect, the base layer can be completely covered with the barrier layer. Therefore, it is possible to reduce the possibility that the base layer is exposed on the barrier layer. Therefore, the possibility of diffusion of the metal contained in the base layer to the outer surface side of the negative electrode current collector can be reduced.

(5) In the above aspect, the plating layer may have a thickness of not less than 2 μm and not more than 5 μm. According to this aspect, the alloy layer can be completely covered with the plating layer. Therefore, when hydrogen is generated in the negative electrode, it is possible to reduce the possibility that a layer such as an alloy layer having a function of holding hydrogen is exposed at the outer surface of the negative electrode current collector. Therefore, generation of hydrogen in the negative electrode can be further suppressed.

(6) In the above mode, the barrier layer may contain at least one different element selected from the group consisting of boron, aluminum, phosphorus, titanium, and cobalt, which is different from the transition metal. According to this aspect, by containing a different element in the barrier layer, additional functions such as reducing the solubility of the negative electrode active material in the electrolytic solution can be imparted.

(7) In the above mode, the plating layer may further contain at least one element selected from among indium and bismuth. According to this aspect, the plating layer contains a metal whose exchange current density related to the hydrogen evolution reaction is equal to or less than that of tin. Accordingly, the exchange current density of the plating layer involved in the hydrogen evolution reaction can be reduced. Therefore, generation of hydrogen in the negative electrode can be further suppressed.

(8) According to another aspect of the present disclosure, a battery is provided. The battery has: a negative electrode, the negative electrode includes the negative electrode current collector and the negative electrode active material described in the above manner; a positive electrode, the positive electrode includes the positive electrode current collector and the positive electrode active material; a positive electrode separated; and an electrolytic solution accommodated in a region where the negative electrode, the positive electrode, and the separator are arranged. According to this aspect, the negative electrode current collector constituting the battery has a barrier layer mainly composed of a transition metal, an alloy layer obtained by alloying a transition metal with tin, and a plating layer mainly composed of tin. Thus, generation of hydrogen in the negative electrode having the negative electrode current collector can be suppressed. In addition, when hydrogen is generated in the negative electrode, the hydrogen can be retained in layers such as an alloy layer located inside the outer surface of the negative electrode current collector. Therefore, it is possible to suppress hydrogen from adhering to the outer surface of the negative electrode. Therefore, it is possible to suppress a decrease in the function of the battery due to hydrogen adhesion at the outer surface of the negative electrode.

The present disclosure may be implemented in various ways other than the negative electrode current collector and battery. For example, it can be implemented as a method of manufacturing a negative electrode current collector, a method of controlling a battery having a negative electrode current collector, a computer program for realizing the control method, a non-transitory recording medium recording the computer program, and the like.

Description of drawings

The features, advantages and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, wherein like symbols represent like elements, wherein:

[figure 1]

FIG. 1 is a schematic cross-sectional view schematically showing the internal structure of a battery according to this embodiment.

[figure 2]

FIG. 2 is an enlarged view of the area of FIG. 1 .

[image 3]

FIG. 3 is a graph showing measurement results obtained by cyclic voltammetry using the produced negative electrode.

[Figure 4]

FIG. 4 is a diagram showing conditions of a cycle durability test.

[Figure 5]

FIG. 5 is a graph showing the results of a cycle durability test.

Detailed ways

A. Implementation method:

A-1. The composition of the battery:

FIG. 1 is a schematic cross-sectional view schematically showing the internal structure of a battery 1 according to the present embodiment. FIG. 1 shows a view obtained by cutting the battery 1 along a plane along the longitudinal direction. In the present embodiment, the battery 1 is a cylindrical nickel-zinc secondary battery in which a battery container body is sealed with an upper cover and a lower cover. It should be noted that the type and shape of the battery 1 are not limited thereto. The battery 1 can be, for example, a nickel-cadmium storage battery. In addition, the outer shape of the battery 1 may be, for example, a stacked type, a square type, or a pouch type.

The battery 1 comprises a negative electrode 2 , a positive electrode 5 , two separators C1 , C2 and an electrolyte 8 . The negative electrode 2, the positive electrode 5, the two separators C1, C2 and the electrolyte 8 are housed in the internal space of the battery 1 surrounded by the battery container main body, the upper cover and the lower cover. Negative electrode 2 , positive electrode 5 , and separators C1 and C2 are immersed in electrolytic solution 8 in the internal space of battery 1 .

The negative electrode 2 includes a negative electrode current collector 20 and a negative electrode active material 28 . The negative electrode current collector 20 has conductivity. The negative electrode current collector 20 is electrically connected to an unillustrated negative electrode terminal. The details of the negative electrode current collector 20 will be described later using FIG. 2 .

The negative electrode active material 28 contributes to the redox reaction in the negative electrode 2 . In the present embodiment, negative electrode active material 28 contains at least one of zinc (Zn) and zinc oxide as a main component. Specifically, as the main component of the negative electrode active material 28 , for example, at least one of zinc (Zn) and zinc oxide (ZnO) as a simple substance is used. In the case where the main component of the negative electrode active material 28 is zinc, for example, a zinc alloy containing zinc can be used. In the present disclosure, "main component" means "a proportion greater than 50% by mass".

The negative electrode active material 28 may also contain additives such as thickeners, binders, and other inorganic substances. The thickener is, for example, cellulose-based polymers such as carboxymethylcellulose (CMC). The binder is, for example, a fluorine-containing resin such as polytetrafluoroethylene (PTFE). It should be noted that the components and composition constituting the negative electrode active material 28 are not limited thereto. In addition, the additive of the negative electrode active material 28 may be a component having properties of improving corrosion resistance, wettability, conductivity, and the like.

The positive electrode 5 includes a positive electrode current collector 50 and a positive electrode active material 58 . The positive electrode current collector 50 has conductivity. The positive electrode current collector 50 is electrically connected to an unillustrated positive electrode terminal. The positive electrode current collector 50 contains a conductive metal as a main component. The conductive metal used in the positive electrode current collector 50 is, for example, any of aluminum (Al), an alloy mainly composed of aluminum, nickel (Ni), and titanium (Ti). In the present embodiment, the positive electrode current collector 50 contains nickel as a main component. In addition, the positive electrode active material 58 may contain additives, such as a thickener, a binder, and other inorganic substances similarly to the negative electrode active material 28.

The positive electrode active material 58 contributes to oxidation-reduction reactions in the positive electrode 5 . In this embodiment, the positive electrode active material 58 contains nickel (Ni) or nickel hydroxide as a main component. The positive electrode active material 58 is, for example, nickel hydroxide (Ni(OH) ₂ ).

The separators C1 and C2 separate the negative electrode 2 and the positive electrode 5 . Specifically, the separators C1 and C2 are walls provided between the negative electrode 2 and the positive electrode 5 in order to prevent an internal short circuit caused by contact between the negative electrode 2 and the positive electrode 5 . In the present embodiment, the first separator C1 is arranged on the negative electrode 2 side, and the second separator C2 is arranged on the positive electrode 5 side. The separators C1 and C2 are insulating and allow the electrolyte solution 8 to pass through. The separators C1 and C2 are, for example, porous films formed of polyolefins such as polypropylene (PP) and polyethylene (PE). The separators C1 and C2 may also contain nonwoven fabrics made of chemical fibers or the like. The chemical fibers are, for example, any of polypropylene fibers, cellulose fibers, polyvinyl alcohol (PVA) fibers, and ethylene-vinyl acetate (EVA) fibers.

The electrolytic solution 8 is a conductive liquid. The electrolytic solution 8 is composed of either an aqueous electrolytic solution such as an alkaline aqueous solution or a non-aqueous electrolytic solution containing an organic electrolyte such as a lithium salt. In this embodiment, the electrolytic solution 8 is an alkaline aqueous electrolytic solution. The basic aqueous electrolytic solution as electrolytic solution 8 contains an alkali metal hydroxide and water. Electrolyte solution 8 is, for example, potassium hydroxide (KOH) aqueous solution, sodium hydroxide (NaOH) aqueous solution, lithium hydroxide (LiOH) aqueous solution. The electrolytic solution 8 can be used by mixing various alkaline aqueous solutions. In this embodiment, the electrolytic solution 8 is an alkaline mixed aqueous solution containing potassium hydroxide as a main component and adding sodium hydroxide and lithium hydroxide. Electrolyte solution 8 may also contain other inorganic and organic additives.

FIG. 2 is an enlarged view of a region R2 in FIG. 1 . The negative electrode current collector 20 has a base layer 210 , a barrier layer 230 , an alloy layer 250 and a plating layer 270 . The negative electrode current collector 20 is a laminate formed by laminating these layers 210 , 230 , 250 , and 270 . In negative electrode current collector 20 , base layer 210 , barrier layer 230 , alloy layer 250 , and plated layer 270 are stacked sequentially from the inside of negative electrode current collector 20 toward current collector outer surface 20 a which is the outer surface of negative electrode current collector 20 . The base layer 210 is located at the center of the inner side of the negative electrode current collector 20 which is a laminated body. The barrier layer 230 is laminated on the base layer 210 . The alloy layer 250 is stacked on the barrier layer 230 . Plating layer 270 is laminated on alloy layer 250 to form current collector outer surface 20a. That is, as shown in FIG. 1 , the plating layer 270 is provided at a position in contact with at least one of the electrolytic solution 8 and the negative electrode active material 28 .

In the negative electrode 2 , in the case where an aqueous electrolytic solution is used as the electrolytic solution 8 , a charge-discharge reaction represented by the following formula (1) occurs. Specifically, zinc (Zn), which is the negative electrode active material 28 , reacts with hydroxide ions (OH ⁻ ) present in an ionized state in the electrolytic solution 8 to be oxidized. Thereby, electrons (e ⁻ ) are generated together with zinc hydroxide (Zn(OH) ₂ ). In the following formula (1), the reaction from the left to the right is the discharge reaction. In addition, in the following formula (1), the reaction from the right to the left is a charging reaction.

Zn+2OH ^- →Zn(OH) ₂ +2e ^-Formula (1)

The base layer 210 has a function as a collector that collects electrons generated by the reaction of the above formula (1), and a function as a support that supports the other layers 230 , 250 , and 270 . The base layer 210 is a conductor mainly composed of a conductive metal. In this embodiment, base layer 210 contains copper (Cu) as a main component. The thickness of the base layer 210 can be set to any thickness within the range capable of functioning as a current collecting portion and a supporting portion. It should be noted that the main component of the base layer 210 is not limited thereto. The base layer 210 may be, for example, an alloy of copper and tin. In addition, the shape of the base layer 210 may be, for example, a plate shape, a foil shape, a mesh shape, a sponge shape, or a fiber shape.

Here, in the negative electrode 2, when an aqueous electrolytic solution is used as the electrolytic solution 8, hydrogen (H ₂ ) may be generated in the negative electrode 2 as shown in the following formula (2). Specifically, the electrons generated in the above formula (1) do not flow to the positive electrode 5 side, but contribute to the reaction of reducing water molecules (H ₂ O) in the electrolytic solution 8 , thereby generating hydrogen. In the case where hydrogen is generated in the negative electrode 2 , the function of the battery 1 may be lowered because the generated hydrogen adheres to the outer surface 2 a of the negative electrode 2 . Therefore, in the present embodiment, in the negative electrode current collector 20 constituting the negative electrode 2 , the alloy layer 250 is provided between the barrier layer 230 and the plating layer 270 in order to suppress the generation of hydrogen in the negative electrode 2 . The alloy layer 250 is a layer obtained by alloying the barrier layer 230 as the first base material and the plated layer 270 as the second base material. By providing the barrier layer 230, the alloy layer 250, and the plating layer 270, generation of hydrogen in the negative electrode 2 can be suppressed. The details thereof will be described later. It should be noted that hydrogen may also be generated in the negative electrode 2 when a hygroscopic non-aqueous electrolytic solution is used.

2H ₂ O+2e ^- →H ₂ +2OH ^-Formula (2)

The barrier layer 230 suppresses the diffusion of the conductive metal (copper in this embodiment) contained in the base layer 210 to the collector outer surface 20 a side by covering the base layer 210 . The barrier layer 230 also becomes the first base material for forming the alloy layer 250 . The barrier layer 230 completely covers the entire surface of the base layer 210 . The barrier layer 230 is formed on the base layer 210 by electroplating, for example. It should be noted that the barrier layer 230 may also be formed on the base layer 210 by other methods such as hot-dip plating, vapor phase plating, and electroless plating.

Barrier layer 230 preferably has a thickness such that copper contained in base layer 210 does not diffuse to the collector outer surface 20 a side where electrolytic solution 8 exists. Specifically, the thickness of the barrier layer 230 is preferably not less than 2 μm and not more than 10 μm. By setting the thickness of the barrier layer 230 to be 2 μm or more, the base layer 210 can be completely covered with the barrier layer 230 . In addition, the upper limit of the thickness of the barrier layer 230 is set to 10 μm in consideration of workability and cost when electroplating is performed to cover the base layer 210 with the barrier layer 230 . It should be noted that the thickness of the barrier layer 230 is not limited thereto. The thickness of the barrier layer 230 may be greater than 10 μm, for example.

The barrier layer 230 contains a transition metal as a main component. In this embodiment, the transition metal is, for example, at least one of nickel (Ni), iron (Fe), chromium (Cr), zirconium (Zr), and lanthanum (La). In order to protect the base layer 210 mainly composed of copper, the transition metal as the main component of the barrier layer 230 preferably satisfies the following condition (i). In addition, in order to suppress the generation of hydrogen by the reaction formula of the above formula (2), the transition metal which is the main component of the barrier layer 230 preferably satisfies the following condition (ii). In order to suppress the generation of hydrogen in the negative electrode 2 , it is conceivable to make the reaction of generating hydrogen represented by the above formula (2) (hereinafter referred to as the hydrogen evolution reaction) less likely to occur. The following condition (ii) is an example of a condition for realizing a method for making the hydrogen evolution reaction represented by the above formula (2) less likely to occur.

(i) a transition metal that can suppress the diffusion of copper from the base layer 210 to the side of the plated layer 270 forming the outer surface 20a of the current collector when the base layer 210 mainly composed of copper is covered with the barrier layer 230

(ii) The following transition metals: the exchange current density in the hydrogen evolution reaction represented by the above formula (2) is smaller than that of gold (Au)

As shown in the above condition (i), in order to suppress the diffusion of copper, which is the main component of the base layer 210, to the side of the plated layer 270 forming the outer surface 20a of the current collector, it is preferable to select a transition metal suitable as the barrier layer 230 covering the base layer 210. In order to suppress the diffusion of copper contained in the base layer 210 to the plated layer 270 side, the transition metal used for the plated layer 270 is preferably any one of nickel (Ni) and iron (Fe), for example. In addition, in order to suppress the diffusion of copper contained in the base layer 210 to the plating layer 270 side, transition metals that are not suitable as transition metals for the plating layer 270 are, for example, indium (In), tin (Sn), and bismuth (Bi). either.

As shown in the above condition (ii), it is preferable to select a transition metal that is less likely to cause the hydrogen evolution reaction represented by the above formula (2) as the main component of the barrier layer 230 . In the present embodiment, transition metals are classified into three groups according to the magnitude of the exchange current density involved in the hydrogen evolution reaction represented by the above formula (2). Specifically, the exchange current density involved in the hydrogen evolution reaction represented by the above formula (2) is set as the first group, and the exchange current density involved in the hydrogen evolution reaction represented by the above formula (2) is smaller than that of gold. One group serves as the second and third groups. The second group is transition metals whose exchange current density involved in the hydrogen evolution reaction represented by the above formula (2) is smaller than that of gold, but which is higher than that of the metals belonging to the third group. It should be noted that some of the elements belonging to the third group also include elements not belonging to transition metals, but since the plating layer 270 is necessary for the description later, it will be described here in advance.

The transition metal belonging to the first group is, for example, any of rhodium (Rh), rhenium (Re), iridium (Ir), and platinum (Pt). The transition metal belonging to the second group is, for example, any of nickel (Ni), iron (Fe), and cobalt (Co). The metal belonging to the third group is, for example, any of indium (In), tin (Sn), bismuth (Bi), and titanium (Ti). Belong to the transition metal of the first group because the exchange current density involved in the hydrogen evolution reaction shown in the above formula (2) is greater than gold, and relatively greater than the transition metals belonging to the second group and the third group, so it may easily cause the above formula ( 2) Case of the indicated reaction. In contrast, the transition metals belonging to the second group and the third group are relatively smaller than the metals belonging to the first group because the exchange current density involved in the hydrogen evolution reaction shown in the above formula (2) is relatively smaller than that of the transition metals using the first group The reaction represented by the above formula (2) is less likely to occur compared with the case of the above. Therefore, when the transition metal belonging to the second group and the third group is used as the main component of the barrier layer 230, the possibility of causing the hydrogen evolution reaction represented by the above formula (2) can be reduced. Therefore, as shown in the above condition (ii), it is preferable to select transition metals belonging to the second group and the third group whose exchange current density involved in the hydrogen evolution reaction shown in the above formula (2) is smaller than that of gold as the main component of the barrier layer 230 .

From the above, nickel is used in this embodiment as a transition metal satisfying the above-mentioned condition (i) and the above-mentioned condition (ii).

It should be noted that the barrier layer 230 may contain at least one dissimilar element selected from boron, aluminum, phosphorus, titanium, and cobalt, which is different from the transition metal that is the main component of the barrier layer 230 . By containing a foreign element such as phosphorus in the barrier layer 230 , additional functions such as reducing the solubility of the negative electrode active material 28 in the electrolytic solution 8 can be imparted.

The plated layer 270 is formed on the outer surface 20a of the current collector to protect the inner layer, such as the alloy layer 250 . Plated layer 270 also serves as a second base material for forming alloy layer 250 . The plating layer 270 completely covers the entire surface of the barrier layer 230 . The surface of the barrier layer 230 referred to here refers to the surface of the barrier layer 230 opposite to the surface in contact with the base layer 210 . The plating layer 270 is formed on the barrier layer 230 by electroplating, for example. It should be noted that the plating layer 270 may also be formed on the barrier layer 230 by other methods such as hot-dip plating, vapor phase plating, and electroless plating.

Plated layer 270 is preferably able to protect alloy layer 250 and has a thickness such that a desired thickness of alloy layer 250 can be obtained when alloyed with plated layer 270 and barrier layer 230 . Specifically, the thickness of the plating layer 270 is preferably not less than 2 μm and not more than 5 μm. When the thickness of the plating layer 270 is thin, for example, less than 2 μm, pinholes are generated when covering the surface of the barrier layer 230 or the plating layer 270 formed on the barrier layer 230 becomes uneven on the surface of the barrier layer 230 . As a result, barrier layer 230 may be exposed so as to be in contact with electrolyte solution 8 . In addition, the upper limit of the thickness of the plating layer 270 is set to 5 μm in consideration of workability and cost when electroplating is performed to cover the barrier layer 230 with the plating layer 270 . It should be noted that the thickness of the plating layer 270 is not limited thereto. The thickness of the plating layer 270 may be greater than 10 μm, for example.

The plating layer 270 contains tin (Sn) as a main component. The reasons for selecting tin as the main component of the plating layer 270 are the following four reasons. First, the inventors of the present application found that the generation of hydrogen in the negative electrode 2 can be suppressed by providing the alloy layer 250 obtained by alloying nickel and tin in the negative electrode current collector 20 . Second, as mentioned above, the exchange current density involved in the hydrogen evolution reaction represented by the above formula (2) of tin is small, and it is difficult to generate hydrogen. Third, tin is widely used as a plating material, and the film formed on the object (in this embodiment, the barrier layer 230 and the alloy layer 250 ) is excellent in flexibility and operability in plating work. Fourth, by covering the target object with tin, the corrosion resistance of the target object can be improved. For the above reasons, in the present embodiment, tin is used as the main component of the plating layer 270 .

The plating layer 270 may contain at least one of indium (In) and bismuth (Bi) as an additive. Indium and bismuth are transition metals belonging to the third group whose exchange current density involved in the hydrogen evolution reaction represented by the above formula (2) is smaller than that of gold. Therefore, the exchange current density of the plating layer 270 can be further reduced compared to the case where at least one of indium and bismuth is not included in the plating layer 270 . In addition, indium and bismuth can generally help to improve the corrosion resistance of the negative electrode active material 28 .

The alloy layer 250 helps to suppress the generation of hydrogen in the negative electrode 2 . Specifically, the negative electrode current collector 20 holds hydrogen generated on the outer surface 2 a of the negative electrode 2 in layers such as the alloy layer 250 located inside the current collector outer surface 20 a. The alloy layer 250 is formed by maintaining the stacked state for a predetermined time in a stacked state in which the base layer 210 , the barrier layer 230 , and the plated layer 270 are sequentially stacked from the inside toward the current collector outer surface 20 a. Specifically, nickel as a main component of barrier layer 230 and tin as a main component of plating layer 270 are alloyed by natural diffusion while maintaining the laminated state. Thus, the alloy layer 250 is formed between the barrier layer 230 and the plating layer 270 . In this embodiment, the alloy layer 250 is an alloy of nickel and tin.

When the alloy layer 250 is formed, the plated layer 270 may be heat-treated in a laminated state. For example, as heat treatment, the plated layer 270 is heated at 220° C. for 10 minutes. The heat treatment for the plating layer 270 is a so-called reflow treatment. By heat-treating the plating layer 270, the plating layer 270 can be made uniform. Accordingly, it is possible to suppress uneven plating layer 270 and occurrence of pinholes. Therefore, it is possible to reduce the possibility that the alloy layer 250 formed between the barrier layer 230 and the plating layer 270 is exposed on the current collector outer surface 20 a of the negative electrode current collector 20 . It should be noted that conditions such as heating time and heating temperature in the heat treatment of the plating layer 270 are not limited thereto. The heating temperature in the heat treatment may be lower than 220°C. In addition, the heating time in the heat treatment may be longer or shorter than 10 minutes.

According to the embodiment, the negative electrode current collector 20 has: a base layer 210, a barrier layer 230 mainly composed of a transition metal, an alloy layer 250 obtained by alloying the transition metal of the barrier layer 230 with the tin of the plating layer 270, and The plating layer 270 has tin as a main component. The base layer 210 , the barrier layer 230 , the alloy layer 250 , and the plating layer 270 are stacked sequentially from the inner side toward the outer surface 20 a of the current collector. At this time, by including at least the barrier layer 230 , the alloy layer 250 , and the plating layer 270 in the negative electrode current collector 20 , generation of hydrogen in the negative electrode 2 can be suppressed. In addition, when hydrogen is generated in the negative electrode 2, the hydrogen can be retained in layers such as the alloy layer 250 located inside the current collector outer surface 20a. Therefore, it is possible to suppress hydrogen from adhering to the outer surface 2 a of the negative electrode 2 . Therefore, it is possible to suppress a decrease in the function of the battery 1 due to hydrogen adhesion at the outer surface 2 a of the negative electrode 2 .

In addition, according to the above embodiment, an alkaline aqueous electrolytic solution is used as the electrolytic solution 8 . At this time, in the electrolytic solution 8 of the present embodiment, more hydroxide ions exist in the electrolytic solution than when an acidic or neutral electrolytic solution is used. Electrons generated by the reaction represented by the above formula (1) between the hydroxide ions and the negative electrode active material 28 flow to the positive electrode side, and the battery 1 realizes the discharge function. On the other hand, sometimes the electrons generated by the reaction between the hydroxide ion and the negative electrode active material 28 do not flow to the positive electrode side but contribute to the reduction reaction of water in the electrolytic solution represented by the above formula (2), thereby The reaction represented by the above formula (2) occurs, and hydrogen is generated in the negative electrode 2 . Even in this case, since the negative electrode current collector 20 has at least the barrier layer 230, the alloy layer 250, and the plated layer 270, hydrogen can be retained in layers such as the alloy layer 250 located inside the current collector outer surface 20a. Therefore, generation of hydrogen in the negative electrode 2 can be suppressed. Therefore, it is possible to suppress a decrease in the function of the battery 1 due to hydrogen adhesion at the outer surface 2 a of the negative electrode 2 .

In addition, according to the embodiment, at least one transition metal of nickel, iron, chromium, zirconium, and lanthanum is used as the main component of the barrier layer 230 . In this case, due to electrons generated by the reaction represented by the above formula (1), water in the electrolytic solution 8 is oxidized as shown by the above formula (2) to generate hydrogen. When hydrogen is generated in the negative electrode 2, the barrier layer 230 may be formed using a transition metal whose exchange current density involved in the hydrogen evolution reaction is smaller than that of gold. Therefore, compared with the case where the barrier layer 230 is formed of a transition metal having a higher exchange current density involved in the hydrogen evolution reaction than gold, the hydrogen evolution reaction represented by the above formula (2) is less likely to occur. Therefore, the barrier layer 230 may be formed using a transition metal capable of suppressing generation of hydrogen in the negative electrode 2 .

In addition, in the above-described embodiment, the thickness of the barrier layer 230 is set to be 2 μm or more and 10 μm or less. Accordingly, the base layer 210 can be completely covered with the barrier layer 230 . Therefore, it is possible to reduce the possibility that the base layer 210 is exposed on the barrier layer 230 . Therefore, it is possible to reduce the possibility that the metal contained in the base layer 210 diffuses toward the collector outer surface 20 a side.

In addition, in the above-described embodiment, the thickness of the plating layer 270 is set to be 2 μm or more and 5 μm or less. Accordingly, the alloy layer 250 can be completely covered with the plating layer 270 . Therefore, when hydrogen is generated in the negative electrode 2, it is possible to reduce the possibility that layers such as the alloy layer 250 having a function of holding hydrogen are exposed on the current collector outer surface 20a. Therefore, generation of hydrogen in the negative electrode 2 can be more reliably suppressed.

In addition, according to the above embodiment, the barrier layer 230 may contain at least one dissimilar element selected from the group consisting of boron, aluminum, phosphorus, titanium, and cobalt, which is different from the transition metal that is the main component of the barrier layer 230 . By containing a foreign element such as phosphorus in the barrier layer 230 , additional functions such as reducing the solubility of the negative electrode active material 28 in the electrolytic solution 8 can be imparted.

In addition, according to the above embodiment, the plating layer 270 may be set to include at least one element of indium and bismuth. That is, the plated layer 270 contains a metal whose exchange current density related to the hydrogen evolution reaction represented by the above formula (2) is smaller than that of gold and equal to or less than that of tin. Accordingly, the exchange current density of the plating layer 270 involved in the hydrogen evolution reaction represented by the above formula (2) can be reduced. Therefore, generation of hydrogen in the negative electrode 2 can be further suppressed.

In addition, according to the above embodiment, heat treatment is performed on the plating layer 270 in a stacked state in which the base layer 210 , the barrier layer 230 , and the plating layer 270 are sequentially stacked from the inside toward the current collector outer surface 20 a. Thereby, the plating layer 270 can be made uniform. That is, it is possible to reduce the possibility of uneven plating layer 270 or occurrence of pinholes. Therefore, in a state where the alloy layer 250 is formed between the barrier layer 230 and the plating layer 270, the possibility of the alloy layer 250 being exposed on the current collector outer surface 20a can be reduced.

A-2. Experiment example:

A-2-1. Experimental Example 1:

On the premise of the configuration described above, samples X1 to X4 serving as negative electrodes 2 of the present embodiment and sample Y1 serving as a comparative example were produced. In this experiment, by comparing the sample Y1 as a comparative example with the samples X1 to X4 of this embodiment, it was confirmed that the generation of hydrogen in the negative electrode 2 due to the presence or absence of the barrier layer 230, the alloy layer 250, and the plating layer 270 was confirmed. difference. The configuration of the negative electrode current collector 20 of the sample Y1 as a comparative example is different from that of the samples X1 to X4. Specifically, the negative electrode current collector 20 of the sample Y1 is not provided with the barrier layer 230 and the plating layer 270 . Thus, the barrier layer 230 , the alloy layer 250 and the plating layer 270 did not exist in the negative electrode current collector 20 of the sample Y1.

Sample X1 was produced as follows. From the viewpoint of conductivity and workability, punching metal made of oxygen-free copper (C1020) is used for the base layer 210 . The barrier layer 230 is completely formed on the base layer 210 . The barrier layer 230 has a thickness of 2 μm. Next, the plating layer 270 is formed on the barrier layer 230 without omission. The thickness of the plating layer 270 was set to 3 μm. Next, in the laminated state in which the base layer 210 , the barrier layer 230 , and the plated layer 270 are sequentially laminated from the inside toward the collector outer surface 20 a , the laminated state is maintained for a predetermined time. Thus, the alloy layer 250 is formed between the barrier layer 230 and the plating layer 270 . A laminate obtained by laminating these layers 210 , 230 , 250 , and 270 is used as the negative electrode current collector 20 .

When making the negative electrode active material 28, powdery zinc oxide, powdery zinc, carboxymethyl cellulose and a dispersion liquid dispersed with polytetrafluoroethylene are mixed in a ratio of 90:10:1:2 by weight to obtain the first mixture. A solution in which water and isopropanol (IPA) were mixed in a weight ratio of 1:1 was dropped in an appropriate amount in the first mixed liquid to obtain a second mixed liquid. A slurry-like ink obtained by stirring the second liquid mixture for 15 minutes using an autorotation-revolution mixer manufactured by Thinky Corporation was used as the negative electrode active material 28 .

When making the negative electrode ² , the negative electrode current collector 20 is coated with the negative electrode active material 28 in such a manner that the negative electrode current collector 20 of 1 cm is coated with the negative electrode active material 28 of about 100 mg, thereby obtaining the negative electrode Mixed material. The negative electrode mixed material was dried at 80° C. for 2 hours, and then pressed at a linear pressure of 0.75 t using a roller press manufactured by Takumi Giken to prepare negative electrode 2 .

The first separator C1 is formed of a polypropylene porous film and a mixed nonwoven fabric mixed with polyvinyl alcohol fibers and cellulose fibers. For one end of the negative electrode 2, a copper foil with a thickness of 120 μm was welded by a resistance welding machine, and then the negative electrode 2 was wrapped with the first separator C1 to form a negative electrode-separator composite.

As the positive electrode current collector 50 , “Celmet (registered trademark)” manufactured by Sumitomo Electric Co., Ltd., which is a porous metal mainly composed of nickel, was used. The positive electrode terminal was welded to the positive electrode 5 composed of the positive electrode current collector 50 and nickel hydroxide as the positive electrode active material 58, and the resultant was stacked to obtain a positive electrode mixture. The second separator C2 is formed of nonwoven fabric. The positive electrode mixture material was welded and embedded by the second separator C2 to form a positive electrode-separator composite.

The negative electrode-separator complex and the positive electrode-separator complex are accommodated in the space formed by the battery container main body and the lower cover, and a predetermined amount of electrolytic solution 8 is added. The electrolytic solution 8 used was an alkaline mixed aqueous solution containing an aqueous potassium hydroxide solution as a main component and mixing an aqueous sodium hydroxide solution and an aqueous lithium hydroxide solution. As a result, the negative electrode-separator complex and the positive electrode-separator complex are immersed in the electrolytic solution 8 . Then, it was sealed with an upper cap, and sample X1 was obtained.

Sample X2 is a sample obtained by heat-treating the plated layer 270 in the negative electrode current collector 20 of the sample X1. In sample X2, heat treatment was performed on the plating layer 270 in a stacked state in which the base layer 210, the barrier layer 230, and the plating layer 270 were laminated in this order from the inner side toward the current collector outer surface 20a. Specifically, in the laminated state, the plating layer 270 was heated at 220° C. for 10 minutes to melt the plating layer 270 . Then, the heated plated layer 270 was rapidly cooled to obtain a sample X2. The other components of sample X2 and the method of making sample X2 are the same as sample X1.

Sample X3 is a sample in which phosphorus, which is a different element different from the main component of the barrier layer 230 , is contained in the barrier layer 230 in the negative electrode current collector 20 of the sample X1. The other components of sample X3 and the method of making sample X3 are the same as sample X1.

Sample X4 is a sample in which the thickness of the barrier layer 230 and the thickness of the plating layer 270 in the negative electrode current collector 20 of the sample X1 were respectively thinned. In sample X4, the barrier layer 230 has a thickness of 1 μm, and the plating layer 270 has a thickness of 2 μm. The other components of sample X4 and the method of making sample X4 are the same as sample X1.

Sample Y1 as a comparative example is a sample in which barrier layer 230 , alloy layer 250 , and plating layer 270 provided in negative electrode current collector 20 of sample X1 were not provided. The other components of sample Y1 and the method of producing sample Y1 are the same as those of sample X1.

FIG. 3 is a graph showing measurement results obtained by cyclic voltammetry using the produced negative electrode 2 . The measurement results of samples X1 to X4 and sample Y1 as a comparative example are shown graphically in FIG. 3 .

Cyclic voltammetry is a basic measurement method in the electrochemical field that repeatedly scans an electrode potential to measure a response current at the time of scanning. In the measurement in FIG. 3 , any one of samples X1 to X4 and Y1, a nickel counter electrode, and a mercury-mercury oxide electrode as a reference electrode were installed in an electrochemical cell. A 6 mol/L potassium hydroxide aqueous solution was added as an electrolytic solution 8 to this electrochemical cell. In this state, the potential of the reference electrode (+0.10 V compared to SHE) was reciprocated once between -1.2 V and -1.9 V. That is, in the measurement related to FIG. 3 , with respect to the potential of the reference electrode (+0.10 V compared to SHE), the scanning in the negative direction from -1.2 V to -1.9 V and the negative direction from -1.9 V to -1.2 Each scan in the positive direction of V is performed once.

The horizontal axis in FIG. 3 represents the potential of the reference electrode. In FIG. 3 , the unit of the potential of the reference electrode is set to [V]. The vertical axis of FIG. 3 represents the response current value with respect to the potential. In FIG. 3, the unit of the response current value is set to [mA]. The graph in FIG. 3 is a so-called cyclic voltammogram showing the change in the response current value at a specific potential. In FIG. 3 , the average value of positive direction scanning and negative direction scanning between -1.2V～-1.9V is represented as a curve. In the cyclic voltammogram, a peak representing a potential difference occurs near the oxidation-reduction potential. In FIG. 3 , the peak formed in the negative direction of the response current value is a reduction wave generated due to fluctuations in the reduction-side current. The peak formed in the positive direction of the response current value is the oxidation wave generated by the fluctuation of the current on the oxidation side.

In FIG. 3 , in sample Y1 in which the barrier layer 230 , the alloy layer 250 , and the plating layer 270 were not provided in the negative electrode current collector 20 , when the potential of the reference electrode became around -1.9V, the reducing side current decreased significantly. In contrast, in sample X1 in which barrier layer 230 , alloy layer 250 , and plating layer 270 were provided in negative electrode current collector 20 , the reduction-side current when the potential of the reference electrode became -1.9 V was around -3.0 mA. That is, when the potential of the reference electrode became −1.9 V, the reduction-side current of the sample X1 was smaller than that of the sample Y1. In other words, when the potential of the reference electrode became -1.9V, the reduction wave of the sample X1 was smaller than that of the sample Y1. In this embodiment, the point when the potential of the reference electrode becomes around -1.9 V corresponds to the oxidation-reduction potential of the hydrogen evolution reaction represented by the above formula (2).

Here, the magnitude of the reduction wave is proportional to the amount of electrons supplied to the negative electrode 2 side. That is, when the reduction wave is large, many electrons are supplied to the negative electrode 2, and the reduction reaction actively proceeds. On the other hand, the smaller the reduction wave, the fewer electrons are supplied to the negative electrode 2, and the reduction reaction is suppressed. Therefore, the sample X1 was able to suppress the generation of hydrogen in the anode 2 including the anode current collector 20 as compared with the sample Y1. That is, in the case where the barrier layer 230 , the alloy layer 250 , and the plating layer 270 are provided in the negative electrode current collector 20 constituting the negative electrode 2 , generation of hydrogen in the negative electrode 2 can be suppressed.

In addition, in FIG. 3 , in sample X1, when the potential of the reference electrode was around -1.5V to -1.4V, fluctuations were observed in the oxidation side current, and oxidation waves were formed. On the other hand, in sample Y1, when the potential of the reference electrode was -1.5 V to -1.4 V, no variation was observed in the oxidation side current, and no oxidation wave was formed.

The magnitude of the oxidation wave is proportional to the amount of electrons lost from the negative electrode 2 side. Specifically, when an oxidation wave is formed, an oxidation reaction occurs as a reaction of losing electrons on the side of the negative electrode 2 . Therefore, even when hydrogen is generated in the negative electrode 2 of the sample X1, it is considered that the oxidation reaction that occurs when the potential of the reference electrode becomes around -1.5V to -1.4V can suppress the occurrence of hydrogen on the outer surface 2a of the negative electrode 2. attached hydrogen. For example, as shown in the following formula (3), the oxidation reaction that occurs when the potential of the reference electrode becomes around -1.5V to -1.4V is considered to be a reaction in which hydrogen is oxidized to generate water. It can also be said that layers such as the alloy layer 250 located on the inner side of the current collector outer surface 20a have oxidation-reduction ability.

2H ₂ +O ₂ →2H ₂ O Formula (3)

It is considered that the oxidation reaction represented by the above formula (3) proceeds more actively as the oxidation wave when the potential of the reference electrode becomes around -1.5V to -1.4V becomes larger. That is, the larger the oxidation wave is, the more the hydrogen generated by the reaction formula of the above formula (2) is oxidized to generate water, so it can be considered that the amount of hydrogen attached to the outer surface 2a of the negative electrode 2 decreases. .

In addition, it is also considered that by providing the barrier layer 230, the alloy layer 250, and the plated layer 270 in the negative electrode current collector 20, the layers such as the alloy layer 250 located inside the outer surface 20a of the current collector function as a hydrogen storage alloy. Specifically, the negative electrode current collector 20 stores hydrogen generated in the negative electrode 2 to form a metal hydride. In other words, layers such as the alloy layer 250 located on the inner side of the current collector outer surface 20a retain hydrogen. In this way, the possibility of suppressing the generation of hydrogen in the negative electrode 2 by storing hydrogen in the state of a metal hydride in the negative electrode current collector 20 is also conceivable.

It is considered that the larger the oxidation wave when the potential of the reference electrode becomes around -1.5 V to -1.4 V, the more active the formation of metal hydride. That is, the greater the oxidation wave, the greater the amount of storage in layers such as the alloy layer 250 located on the inner side of the current collector outer surface 20a, and the smaller the amount of hydrogen attached to the outer surface 2a of the negative electrode 2. In addition, the possibility that hydrogen held in layers such as the alloy layer 250 located on the inner side of the current collector outer surface 20a is oxidized by the reaction formula of the above formula (3) may also be considered.

In addition, in the heat-treated sample X2, the reduction-side current when the potential of the reference electrode became -1.9 V was around -2.5 mA. That is, when the potential of the reference electrode became −1.9 V, the reduction side current of the sample X2 was smaller than that of the sample Y1 as a comparative example, similarly to the sample X1. In addition, when the potential of the reference electrode became -1.9V, the reduction-side current of the sample X2 was smaller than that of the sample X1. As shown in FIG. 3 , in sample X2, when the potential of the reference electrode was around -1.5 V to -1.4 V, similar to sample X1, fluctuations were observed in the oxidation side current, and oxidation waves were formed. At this time, the oxidation wave of the sample X2 has a larger peak than the oxidation wave of the sample X1. Accordingly, by heat-treating the plated layer 270 during the formation of the alloy layer 250 , it is possible to further suppress the generation of hydrogen in the negative electrode 2 .

In the sample X3 in which phosphorus was added to the barrier layer 230 , the reduction-side current when the potential of the reference electrode became −1.9 V was around −2.4 mA. That is, when the potential of the reference electrode became -1.9V, sample X3 had a smaller reduction-side current than sample Y1 as a comparative example, similarly to sample X1. In addition, when the potential of the reference electrode became −1.9 V, the reduction-side current of the sample X3 was smaller than those of the samples X1 and X2. As shown in FIG. 3 , in sample X3, when the potential of the reference electrode was around -1.5 V to -1.4 V, similar to sample X1, fluctuations were observed in the oxidation side current, and oxidation waves were formed. Accordingly, by containing phosphorus in the barrier layer 230 that is a different element different from the main component of the barrier layer 230 , generation of hydrogen in the negative electrode 2 can be further suppressed.

In sample X4 in which the thickness of barrier layer 230 and the thickness of plating layer 270 were respectively thinner than sample X1, the reduction-side current at the time when the potential of the reference electrode was around -1.9V was around -4.5mA. That is, when the potential of the reference electrode became -1.9V, the reduction-side current of sample X4 was smaller than that of sample Y1 as a comparative example, and larger than that of samples X1 to X3. In addition, when the potential of the reference electrode became -1.9V, the reduction-side current value of sample X4 showed a value closer to that of sample Y1 than samples X1 to X3. Thus, in the case where the thickness of the barrier layer 230 is set to 1 μm and the thickness of the plating layer 270 is set to 2 μm, by providing the barrier layer 230 , the alloy layer 250 and the plating layer 270 in the negative electrode current collector 20 , it is also possible to suppress the negative electrode 2 production of hydrogen. On the other hand, compared with the case where the thickness of the barrier layer 230 is set to 2 μm and the thickness of the plating layer 270 is set to 3 μm, in the case where the thickness of the barrier layer 230 is set to 1 μm and the thickness of the plating layer 270 is set to 2 μm , it is difficult to obtain the effect of suppressing the generation of hydrogen in the negative electrode 2 . Therefore, it is more preferable that the thickness of the barrier layer 230 is set to be 2 μm or more, and the thickness of the plating layer 270 is set to be 3 μm or more.

A-2-2. Experimental Example 2:

Furthermore, in order to compare the performance of the battery 1, the cycle durability test of samples X1-X4 and sample Y1 was performed. FIG. 4 is a diagram showing conditions of a cycle durability test. In this test, when the samples X1 to X4 as the battery 1 of the present embodiment and the sample Y1 as a comparative example are repeatedly charged and discharged, until the time point when the functions of the samples X1 to X4 and Y1 are degraded To evaluate the performance of samples X1~X4, Y1 by charging and discharging times. It should be noted that, in the initial state of samples X1 to X4 and Y1 before starting the test, the full charge capacity was set to 120 mAh, and the remaining capacity (SOC) was set to 100%.

As shown in FIG. 4 , in this test, the charging process and the discharging process were repeatedly implemented. A standby time of 5 minutes in which neither the charging process nor the discharging process was performed was provided between the charging process and the discharging process. In this test, the charging step, the first standby time after the charging step and before the discharging step, the discharging step, and the second waiting time before the charging step after the discharging step and starting the next cycle are taken as one cycle. The charging process is performed by a CC-CV method combining constant current charging and constant voltage charging. Specifically, in the charging step, a current was supplied to the samples X1 and Y1 at 1C until the voltage reached 2.00V, and then a current of 60mA was supplied while the voltage was kept at 2.00V. The charging process in this cycle ends when a predetermined cut-off condition indicating completion of charging is reached. The discharge process is performed by a constant current discharge (CC) method. Specifically, in the discharge step, a current was supplied to the samples X1 and Y1 at 1C until the voltage reached 1.1V.

FIG. 5 is a graph showing the results of a cycle durability test. In FIG. 5 , test results of samples X1 to X4 as the battery 1 of the present embodiment and sample Y1 as a comparative example are described. In this test, when the battery capacity at the beginning is set to 100%, the number of cycles when the battery capacity ratio of samples X1~X4, Y1 is reduced to 30% is measured, and the charging capacity of samples X1~X4, Y1 is determined. The point in time when the discharge function is reduced. As shown in FIG. 5 , the sample Y1 without the barrier layer 230 , the alloy layer 250 and the plating layer 270 in the negative electrode current collector 20 reached a battery capacity ratio of 30% after 25 cycles. In contrast, the sample X1 in which the barrier layer 230, the alloy layer 250, and the plating layer 270 were provided in the negative electrode current collector 20 reached a battery capacity ratio of 30% after 154 cycles. That is, by providing the barrier layer 230, the alloy layer 250, and the plating layer 270 in the negative electrode current collector 20, the number of cycles at which the battery capacity ratio is reduced to 30% can be increased. Therefore, the function reduction of the battery 1 can be suppressed.

In the sample X2 subjected to heat treatment, the battery capacity ratio reached 30% after 160 cycles. Thus, by heat-treating the plated layer 270 in the negative electrode current collector 20 , it is possible to further increase the number of cycles at which the battery capacity ratio is reduced to 30%.

The battery capacity ratio of the sample X3 to which phosphorus was added in the barrier layer 230 reached 30% after 255 cycles. Thus, by containing a different element in the barrier layer 230, the number of cycles when the battery capacity ratio is reduced to 30% can be further increased.

Sample X4 having a thickness of the barrier layer 230 and a thickness of the plating layer 270 respectively thinner than that of the sample X1 achieved a battery capacity ratio of 30% after 60 cycles. Thus, in the case where the thickness of the barrier layer 230 is 1 μm and the thickness of the plating layer 270 is 2 μm, by providing the barrier layer 230, the alloy layer 250 and the plating layer 270, the number of cycles when the battery capacity ratio is reduced to 30% can also be increased. On the other hand, compared with samples X1 to X3, sample X4 has a smaller increase in the number of cycles with respect to sample Y1. That is, in the case where the thickness of the barrier layer 230 is 1 μm and the thickness of the plating layer 270 is 2 μm, it is more difficult to increase the number of cycles with respect to the sample Y1 than in the case where the thickness of the barrier layer 230 is 2 μm and the thickness of the plating layer 270 is 3 μm. . Therefore, it is more preferable that the thickness of the barrier layer 230 is 2 μm or more, and the thickness of the plating layer 270 is 3 μm or more.

B. Other implementation modes:

In the embodiment, the type of battery 1 is a nickel-zinc secondary battery, but the present disclosure is not limited thereto. The battery 1 may be, for example, a primary battery. Even in such a form, it is possible to suppress hydrogen from being generated in the negative electrode 2 having the negative electrode current collector 20 and adhering to the outer surface 2 a of the negative electrode 2 .

The present disclosure is not limited to the above-described embodiments, and can be implemented with various configurations without departing from the gist thereof. For example, in order to solve part or all of the above-mentioned problems, or to achieve part or all of the above-mentioned effects, the technical features of the embodiments corresponding to the technical features in the various forms described in the column of the summary of the invention can be appropriately replaced or combined. In addition, if the technical feature is not described as an essential content in this specification, it can be deleted appropriately.

Claims (8)

1. An anode current collector of a battery using an electrolytic solution, wherein the anode current collector has:

a base layer containing a metal having conductivity as a main component;

a barrier layer that is laminated on the base layer and has a transition metal as a main component;

an alloy layer laminated on the barrier layer and obtained by alloying the transition metal with tin; and

a plating layer which is laminated on the alloy layer and has the tin as a main component.

2. The negative electrode current collector according to claim 1, wherein the electrolyte is an alkaline aqueous electrolyte.

3. The negative electrode current collector of claim 1 or claim 2, wherein the transition metal is at least one of nickel, iron, chromium, zirconium, and lanthanum.

4. The anode current collector according to any one of claims 1 to 3, wherein the thickness of the barrier layer is 2 μm or more and 10 μm or less.

5. The negative electrode current collector as claimed in any one of claims 1 to 4, wherein the thickness of the plating layer is 2 μm or more and 5 μm or less.

6. The anode current collector according to any one of claims 1 to 5, wherein the barrier layer contains at least one different element which is different from the transition metal and is selected from boron, aluminum, phosphorus, titanium, and cobalt.

7. The negative electrode current collector as claimed in any one of claims 1 to 6, wherein the plating layer further contains at least one element selected from indium and bismuth.

8. A battery, wherein the battery has:

an anode comprising the anode current collector according to any one of claims 1 to 7 and an anode active material;

a positive electrode including a positive electrode current collector and a positive electrode active material;

a separator separating the negative electrode from the positive electrode; and

an electrolytic solution contained in a region where the anode, the cathode, and the separator are arranged.

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