Battery processing method and battery

Abstract

The invention relates to a battery processing method and a battery. The main purpose of the present disclosure is to provide a method for processing a battery capable of excellently deactivating the battery. The present disclosure solves the above problem by providing a battery processing method having an immersion step in which a battery including an Al terminal is immersed in a processing liquid containing water and a supporting salt, and the voltage of the battery is reduced by an external short circuit through the processing liquid, the Al terminal has, on at least a portion of the surface thereof, a protective layer that suppresses elution of the Al terminal into the processing liquid.

Description

Technical Field The present disclosure relates to a method for treating a battery and a battery. Background Art A battery generally has terminals for taking out electricity from an electrode body as a power generation element. For example, Patent Document 1 discloses a battery module having a laminated outer package flat battery, the laminated outer package flat battery having a positive terminal lead and a negative terminal lead, and the positive terminal lead being made of aluminum. In addition, Patent Document 2 discloses that the resistance to an electrolytic solution is improved by treating the surface of an outer package body made of aluminum. Prior Art Documents Patent Documents Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-257849 Patent Document 2: Japanese Unexamined Patent Application Publication No. 2001-266945 Summary of the Invention Problems to be Solved by the Invention When a battery is recycled, it is desired to reduce the residual voltage of the battery and deactivate the battery. As a method for deactivating the battery, for example, a method of immersing the battery in a treatment liquid (for example, brine) to cause an external short circuit thereof can be cited. In a battery including an aluminum terminal (Al terminal), the Al terminal may be deteriorated by the treatment liquid, and it is difficult to deactivate the battery well. The present disclosure has been completed in view of the above actual situation, and a main object thereof is to provide a method for treating a battery that can deactivate the battery well. Means for Solving the Problems

[0001] A method for treating a battery, which includes an immersion step of immersing a battery including an Al terminal in a treatment liquid, and reducing the voltage of the battery by an external short circuit via the treatment liquid, wherein the treatment liquid contains water and a supporting salt, and the Al terminal has a protective layer on at least a part of the surface thereof that suppresses the dissolution of the Al terminal into the treatment liquid.

[0002] The method for treating a battery according to [1], wherein the method for treating a battery has a protective layer forming step of forming the protective layer on the surface of the Al terminal before the immersion step.

[0003] The method for treating a battery according to [1], wherein the battery has: an electrode body, an outer package body covering the electrode body, and the Al terminal, the Al terminal being electrically connected to the electrode body and partially exposed from the outer package body, and the protective layer is formed on the surface of the Al terminal located inside the outer package body.

[0004] The method for treating a battery according to any one of [1] to [3], wherein the protective layer is an aluminum oxide layer.

[0005] The method for treating a battery according to [4], wherein the alumina layer is a boehmite layer.

[0006] The method for treating a battery according to any one of [1] to [3], wherein the protective layer is a conductive resin layer.

[0007] The method for treating a battery according to any one of [1] to [3], wherein the protective layer is a plating layer.

[0008] A method for treating a battery, which has an impregnation step, wherein a battery including an Al terminal is impregnated in a treatment liquid, and the voltage of the battery is reduced by an external short circuit via the treatment liquid. The treatment liquid contains water and a supporting salt, and the material of the Al terminal is an Al-Mg-Si-based alloy or an Al-Ni clad material.

[0009] A battery is a battery including an Al terminal, and the Al terminal has a protective layer on at least a part of its surface that suppresses the dissolution of the Al terminal into the treatment liquid.

[0010] The battery according to [9], wherein the battery has an electrode body, an outer package body covering the electrode body, and the Al terminal. The Al terminal is electrically connected to the electrode body and a part thereof is exposed from the outer package body. When viewed in the thickness direction, the protective layer is selectively formed in a region of an end portion on the side of the outer package body including the Al terminal.

[0011] A battery is a battery including an Al terminal, and the material of the Al terminal is an Al-Mg-Si-based alloy or an Al-Ni clad material.

[0012] The battery according to any one of [9] to

[11] , wherein the battery has a laminated outer package body.

[0013] The battery according to any one of [9] to

[12] , wherein the battery is a solid battery. Effects of the Invention This disclosure exhibits the effect of enabling the battery to be deactivated well. Description of the Drawings Figure 1 Schematic top view and schematic side view for exemplifying the battery in this disclosure. Figure 2 Schematic side view for exemplifying the method for treating a battery in this disclosure. Figure 3 Schematic top view and schematic cross-sectional view for exemplifying a part of the battery and the protective layer in this disclosure. Figure 4 Schematic cross-sectional view for exemplifying the protective layer in this disclosure. Figure 5 A schematic top view showing the position of the protective layer in the present disclosure. Figure 6 A schematic cross-sectional view showing the electrode body in the present disclosure. Figure 7 A schematic side view showing the method for treating a battery in the present disclosure. Explanation of reference numerals 1... Negative current collector 2... Negative electrode active material layer 3... Electrolyte layer 4... Positive electrode active material layer 5... Positive current collector 10... Electrode body 20... Outer package 30... Terminal 40... Treatment bath 50... Treatment liquid 60... Protective layer 100... Battery Detailed description of specific embodiments The method for treating a battery and the battery in the present disclosure are described in detail below with reference to the accompanying drawings. Each of the figures shown below is schematically illustrated, and for ease of understanding, the sizes and shapes of the respective parts are exaggerated as appropriate. In addition, in this specification, when expressing a scheme of disposing another member with respect to a certain member and simply denoting it as "above" or "below", unless otherwise specified, it includes both the case of disposing another member directly above or directly below in contact with a certain member and the case of disposing another member above or below a certain member via another member. A. Method for treating a battery The method for treating a battery in the present disclosure can be roughly divided into two embodiments. The method for treating a battery in the present disclosure is described by dividing it into a first embodiment and a second embodiment. A-1. First embodiment The method for treating a battery in the first embodiment has an immersion step, in which a battery including an Al terminal is immersed in a treatment liquid, and the voltage of the battery is reduced by an external short circuit via the treatment liquid. The treatment liquid contains water and a supporting salt, and the Al terminal has a protective layer on at least a part of its surface that inhibits the dissolution of the Al terminal into the treatment liquid. Figure 1 (a) and (b) are a schematic top view and a schematic side view showing the battery in the first embodiment. As Figure 1As shown in (a) and (b), the battery 100 includes: an electrode body 10, an outer packaging body 20 that covers the electrode body 10, and terminals 30 (30A, 30B) that are electrically connected to the electrode body 10 and partially exposed from the outer packaging body 20. At least one of the terminal 30A and the terminal 30B is an Al terminal. In Figure 1 (a) and (b), the terminal 30A corresponds to the Al terminal 30X. Figure 2 is a schematic side view illustrating a method for treating a battery in the first embodiment. As Figure 2 shown, a treatment liquid 50 is poured into a treatment bath 40, and the battery 100 is immersed in the treatment liquid 50. The terminals 30A and 30B are electrically connected via the treatment liquid 50, thereby causing an external short circuit and reducing the voltage of the battery 100. In the first embodiment, the Al terminal 30X has a protective layer 60 on at least a part of its surface that inhibits the dissolution of the Al terminal 30X into the treatment liquid 50. According to the first embodiment, since the Al terminal has a protective layer on its surface, the battery can be deactivated well. As described above, when recycling a battery, it is desirable to reduce the residual voltage of the battery and deactivate the battery. By deactivating the battery, subsequent processes such as a battery disassembly process can be performed safely. As a method for deactivating a battery, a method of immersing the battery in a treatment liquid (e.g., brine) to cause an external short circuit can be cited. In a battery including an Al terminal, sometimes the Al terminal deteriorates due to the treatment liquid, and it is difficult to deactivate the battery well. For example, due to the treatment liquid, corrosion (dissolution) of the Al terminal occurs, and if the Al terminal exposed from the outer packaging body slips off, sometimes the reduction of the residual voltage due to the external short circuit no longer occurs or the reduction speed significantly decreases. In the first embodiment, a protective layer that inhibits the dissolution of the Al terminal into the treatment liquid is formed on the surface of the Al terminal. Thereby, deterioration of the Al terminal due to the treatment liquid can be suppressed. Therefore, when the battery is immersed in the treatment liquid, an external short circuit can be maintained, and the battery can be deactivated well. 1. Immersion process The immersion process in the first embodiment is a process of immersing a battery including an Al terminal in a treatment liquid and reducing the voltage of the battery by an external short circuit via the treatment liquid. In the first embodiment, the Al terminal has a protective layer on at least a part of its surface that inhibits the dissolution of the Al terminal into the treatment liquid. The protective layer can be formed by performing a protective layer formation process before the immersion process. Details of the protective layer formation process will be described later. Furthermore, in the method for treating a battery in the first embodiment, it is not necessary to completely prevent deterioration of the Al terminal, and it is sufficient to use the protective layer to inhibit deterioration of the Al terminal to an extent that allows the battery to be deactivated well. (1) Battery As Figure 1As shown in (a) and (b), the battery 100 generally has: an electrode body 10, an outer packaging body 20 covering the electrode body 10, and terminals 30 (30A, 30B) that are electrically connected to the electrode body 10 and a part of which protrudes from the outer packaging body 20. In addition, at least one of the terminal 30A and the terminal 30B is an Al terminal. In Figure 1 (a) and (b), the terminal 30A corresponds to the Al terminal 30X. In the first embodiment, the unit composed of the electrode body, the outer packaging body, and a pair of terminals is sometimes referred to as a "battery cell". The battery processed by the processing method in the first embodiment may have one battery cell or multiple battery cells. Multiple battery cells are usually stacked in the thickness direction. (i) Terminal The battery in the first embodiment generally has a positive terminal and a negative terminal. At least one of the positive terminal and the negative terminal is an Al terminal. Among them, it is preferably that at least the positive terminal is an Al terminal. The Al terminal is a terminal containing at least aluminum. The Al terminal preferably contains aluminum as the main component of the metal component. In the Al terminal, the proportion of aluminum is, for example, 50% by weight or more, can be 70% by weight or more, and can be 90% by weight or more with respect to all the metal components. As the material of the Al terminal, for example, aluminum and aluminum alloy can be cited. There is no particular limitation on the shape of the Al terminal. In addition, there is no particular limitation on the thickness of the Al terminal. The thinner the Al terminal, the greater the influence of the treatment liquid on the deterioration of the Al terminal. The thickness of the Al terminal refers to the length of the Al terminal in the normal direction of the main surface (the surface with the largest area) of the Al terminal. The thickness of the Al terminal is, for example, 5 mm or less, can be 3 mm or less, can be 1 mm or less, can be 0.8 mm or less, and can be 0.6 mm or less. On the other hand, the thickness of the Al terminal is, for example, 0.1 mm or more. The Al terminal has a protective layer on at least a part of its surface that inhibits the dissolution of the Al terminal into the treatment liquid. The Al terminal and the protective layer can be arranged in contact with each other, or can be arranged via other layers. As an example of the protective layer, an alumina layer can be cited. The alumina layer can be formed, for example, by oxidizing the surface of the Al terminal. It should be noted that the "alumina layer" in the first embodiment does not include the natural oxide film of the Al terminal. The natural oxide film is usually 5 nm or less. And the thickness of the alumina layer in the first embodiment is usually larger than 5 nm. As the alumina layer, for example, a boehmite layer and an alimite layer can be cited. The boehmite layer is formed, for example, by subjecting the Al terminal to a boehmite treatment. The boehmite treatment is a type of chemical conversion treatment, and is, for example, a treatment for chemically forming an alumina layer on the surface of the Al terminal by bringing the Al terminal into contact with water or water vapor at a high temperature (for example, 70 °C or higher). The thickness of the boehmite layer is, for example, 100 nm or more and 2 μm or less. The alimite layer is formed, for example, by subjecting the Al terminal to an acid-resistant anticorrosion treatment. The acid-resistant anticorrosion treatment is equivalent to an anodic oxidation treatment, and is, for example, a treatment for electrochemically forming an alumina layer on the surface of the Al terminal by using the Al terminal as an anode and performing electrolysis treatment. The thickness of the alimite layer is, for example, 0.5 μm or more and 50 μm or less, and can be 1 μm or more and 20 μm or less. In addition, in the first embodiment, an alumina layer can be formed by heating the surface of the Al terminal. As other examples of the protective layer, a conductive resin layer can be cited. The conductive resin layer has, for example, a resin (including rubber) and a conductor. As the above resin, for example, polyolefin resins such as polyethylene, polypropylene, and polystyrene; imide resins such as polyimide and polyamideimide; amide resins such as polyamide; acrylic resins such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, and acrylic acid; methacrylic resins such as polymethyl methacrylate, polyethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and polymethacrylic acid; carboxylic resins such as itaconic acid, crotonic acid, fumaric acid, angelic acid, and carboxymethyl cellulose; fluorine resins such as polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), and polytetrafluoroethylene; rubbers such as butadiene rubber, hydrogenated butadiene rubber, styrene-butadiene rubber (SBR), hydrogenated styrene-butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, ethylene-propylene rubber, and fluororubber. On the other hand, as the above conductor, for example, carbon materials, metal particles, and conductive polymers can be cited. As the carbon materials, for example, particulate carbon materials such as acetylene black (AB) and Ketjen black (KB); fibrous carbon materials such as carbon fiber, carbon nanotube (CNT), and carbon nanofiber (CNF). As a method for forming the conductive resin layer, for example, a method of coating a slurry containing a resin, a conductor, and a solvent on the Al terminal and drying it can be cited. As further other examples of the protective layer, a coating layer (plated layer) can be cited. The metal contained in the coating layer can be a metal with a lower ionization tendency (a metal with a higher natural potential) compared to the Al terminal. A metal with a lower ionization tendency compared to the Al terminal has high resistance to the treatment liquid. As such a metal, iron, iron alloy, titanium, titanium alloy, copper, copper alloy, lead, lead alloy, gold, gold alloy, silver, silver alloy, palladium, and palladium alloy can be cited. Further, since the treatment liquid generally does not penetrate between the coating layer and the Al terminal, corrosion (galvanic corrosion) of the Al terminal does not occur. On the other hand, the above metal can be a metal with an ionization tendency similar to that of the Al terminal, or a metal with a higher ionization tendency (a metal with a lower natural potential) compared to the Al terminal. As such a metal, for example, magnesium, magnesium alloy, zinc, and zinc alloy can be cited. In the case of using such a metal, corrosion of the Al terminal does not occur, but corrosion of the coating layer progresses continuously. Therefore, for example, it is preferable to set the thickness of the coating layer to be sufficiently large. As a method for forming the coating layer, for example, an electroplating method or a chemical plating method can be cited. There is no particular limitation on the thickness of the protective layer. For example, it is 10 nm or more, can be 50 nm or more, can be 100 nm or more, and can be 500 nm or more. On the other hand, the thickness of the protective layer is, for example, 50 μm or less. Figure 3 (a) is a schematic top view showing a part of the battery (before the formation of the protective layer) in the present disclosure. Figure 3 (b) is Figure 3 the cross-sectional view taken along the line A-A of (a). Figure 3 (c) is a schematic top view showing a part of the battery (after the formation of the protective layer) in the present disclosure. Figure 3 (d) is Figure 3 the cross-sectional view taken along the line A-A of (c). As shown in Figure 3 (a) and (b), the Al terminal 30X is electrically connected to the electrode body 10 and a part thereof protrudes from the outer packaging body 20. In the first embodiment, as shown in Figure 3 (c) and (d), before the impregnation process, a protective layer 60 covering at least a part of the Al terminal 30X can be formed (protective layer formation process). On the other hand, in the first embodiment, the protective layer formation process may not be performed before the impregnation process. That is, the battery before the treatment method of the battery in the first embodiment may previously have a protective layer. In this case, as shown in Figure 4 , the protective layer 60 can be formed on the surface of the Al terminal 30X located inside the outer packaging body 20. Conversely, as shown in Figure 3 (d), the protective layer 60 may not be formed on the surface of the Al terminal 30X located inside the outer packaging body 20. As shown in Figure 3 (c), (d) andFigure 4 As shown, the protective layer 60 can be formed on the entire portion of the Al terminal 30X exposed from the outer packaging body 20. On the other hand, although not particularly shown, the protective layer can also be formed on a part of the Al terminal exposed from the outer packaging body. In addition, as Figure 3 (c), (d) and Figure 4 shown, the protective layer 60 can be formed on both surfaces (both sides of the main surface) of the main surface of the Al terminal 30X exposed from the outer packaging body 20. On the other hand, although not particularly shown, the protective layer can be formed only on one surface (one side of the main surface) of the main surface of the Al terminal exposed from the outer packaging body. As Figure 5 (a) shows, when viewed from the thickness direction (z direction), the protective layer 60 can be formed so as to cover the entire Al terminal 30X. On the other hand, as Figure 5 (b) shows, when viewed from the thickness direction (z direction), the protective layer 60 can be formed so as to cover a part of the Al terminal 30X. In Figure 5 (b), the protective layer 60 is formed so as to selectively cover the region including the end portion on the outer packaging body 20 side of the Al terminal 30X. By protecting the region (root region) including the end portion on the outer packaging body 20 side of the Al terminal 30X, when the battery is immersed in the treatment liquid, an external short circuit can be further maintained, and the battery can be deactivated better. In addition, when the battery before the battery treatment method in the first embodiment already has a protective layer that selectively covers the region including the end portion on the outer packaging body side of the Al terminal, an increase in resistance caused by the protective layer can be suppressed, and at the same time, the subsequent protective layer formation process can be omitted. In addition, as Figure 5 (b) shows, the so-called "forming the protective layer so as to selectively cover the region including the end portion on the outer packaging body side of the Al terminal" means that there is a region where the protective layer 60 is not formed on the opposite side of the outer packaging body 20 side of the root region. In addition, when viewed from the thickness direction, the area of the Al terminal is set to S a , and the area of the region where the Al terminal and the protective layer overlap is set to S b , in the case of a the area S b relative to the area S b / S a ), there is no particular limitation, for example, it is 10% or more, it can be 30% or more, it can be 50% or more, it can be 70% or more. (ii) Electrode body The electrode body in the first embodiment functions as a power generation element of the battery. The electrode body generally has a positive current collector, a positive active material layer, an electrolyte layer, a negative active material layer, and a negative current collector in sequence in the thickness direction. Figure 6(a) and (b) are schematic cross-sectional views showing the electrode body in the first embodiment. Figure 6 The electrode body 10 shown in (a) sequentially has a negative electrode current collector 1, a negative electrode active material layer 2, an electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in the thickness direction (z direction). In addition, the negative electrode current collector 1 has a negative electrode tab 1t for connecting to a negative terminal (not shown), and the positive electrode current collector 5 has a positive electrode tab 5t for connecting to a positive terminal (not shown). Figure 6 The electrode body 10 shown in (b) has: a negative electrode current collector 1; a negative electrode active material layer 2x, an electrolyte layer 3x, a positive electrode active material layer 4x, and a positive electrode current collector 5x sequentially arranged in the thickness direction (z direction) from one surface of the negative electrode current collector 1; and a negative electrode active material layer 2y, an electrolyte layer 3y, a positive electrode active material layer 4y, and a positive electrode current collector 5y sequentially arranged in the thickness direction (z direction) from the other surface of the negative electrode current collector 1. Figure 6 In (a) and (b), the positive electrode tab 5t and the negative electrode tab 1t are arranged on the side surface of the electrode body 10 so as to face each other, forming a so-called two-tab structure. On the other hand, although not particularly shown, the positive electrode tab and the negative electrode tab may also be arranged on the same side surface of the electrode body, constituting a so-called single-tab structure. In addition, as Figure 6 shown in (a) and (b), the electrode body 10 can be a single-tab type. In addition, although not particularly shown, the electrode body can be a wound type. In addition, a unit composed of a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer is sometimes referred to as a "power generation unit". The electrode body in the first embodiment can have one power generation unit or multiple power generation units. Multiple power generation units are usually stacked in the thickness direction. The positive electrode active material layer contains at least a positive electrode active material. The positive electrode active material layer may further contain at least one of an electrolyte, a conductive material, and a binder. As the positive electrode active material, for example, an oxide active material can be cited. As the oxide active material, for example, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 and LiNi 0.8 Co 0.15 Al 0.05 O2 and other rock salt layer type active materials, spinel type active materials such as LiMn2O4, and olivine type active materials such as LiFePO4. The shape of the positive electrode active material is, for example, particulate. The electrolyte can be a solid electrolyte or a liquid electrolyte (electrolyte solution). The solid electrolyte can be an organic solid electrolyte such as a gel electrolyte, or an inorganic solid electrolyte such as a sulfide solid electrolyte or an oxide solid electrolyte. Among them, the solid electrolyte is preferably a sulfide solid electrolyte. This is because of its high ionic conductivity. On the other hand, the liquid electrolyte is not particularly limited, and a known electrolyte can be used. In addition, as the conductive material, for example, carbon materials can be cited. In addition, as the binder, for example, rubber-based binders and fluoride-based binders can be cited. The negative electrode active material layer contains at least a negative electrode active material. The negative electrode active material layer may further contain at least one of an electrolyte, a conductive material, and a binder. As the negative electrode active material, for example, metal active materials such as Li, Si, and Sn can be cited; carbon active materials such as graphite; and oxide active materials such as Li4Ti5O 12 and the like. The electrolyte layer is disposed between the positive electrode active material layer and the negative electrode active material layer and contains at least an electrolyte. The electrolyte can be a solid electrolyte or a liquid electrolyte. For the electrolyte, it is the same as the above content. The electrolyte layer can be a solid electrolyte layer containing a solid electrolyte. Furthermore, the solid electrolyte is preferably a sulfide solid electrolyte. In addition, generally, a battery having a solid electrolyte layer containing an inorganic solid electrolyte is called a solid battery. The solid battery can be a semi-solid battery or a all-solid battery. In the present disclosure, the semi-solid battery is a battery in which the electrolyte layer has an inorganic solid electrolyte and a liquid component (such as an ionic liquid). In the present disclosure, the all-solid battery is a battery in which the electrolyte layer has only an inorganic solid electrolyte as the electrolyte. The positive electrode current collector collects the current of the positive electrode active material layer. As the material of the positive electrode current collector, for example, metals such as aluminum, SUS, and nickel can be cited. As the shape of the positive electrode current collector, for example, a foil shape can be cited. The positive electrode current collector usually has a positive electrode tab for connecting to the positive electrode terminal. In addition, the negative electrode current collector collects the current of the negative electrode active material layer. As the material of the negative electrode current collector, for example, metals such as copper, SUS, and nickel can be cited. As the shape of the negative electrode current collector, for example, a foil shape can be cited. The negative electrode current collector usually has a negative electrode tab for connecting to the negative electrode terminal. (iii) Outer packaging body The outer packaging body (outer package) in the first embodiment can be a laminated outer packaging body or a case-type outer packaging body. The laminated outer packaging body is also called a bag-type outer packaging body and is an outer packaging body using a laminated film. The laminated outer packaging body has at least an inner resin layer and a metal layer. The inner resin layer functions as a sealant layer. The inner resin layer preferably contains a thermoplastic resin. As the above thermoplastic resin, for example, polyolefins such as polyethylene and polypropylene, polystyrene, and polyvinyl chloride can be cited. The thickness of the inner resin layer is not particularly limited, for example, it is 30 μm or more and 150 μm or less. The metal layer functions as a barrier layer. Examples of the metal used for the metal layer include aluminum, aluminum alloy, and stainless steel. The thickness of the metal layer is not particularly limited, for example, it is 20 μm or more and 100 μm or less. In addition, in the laminated outer package, based on the metal layer, an outer resin layer may be provided on the side opposite to the inner resin layer. The outer resin layer functions as an insulating layer or a protective layer. The outer resin layer preferably contains a thermoplastic resin. Examples of the thermoplastic resin include polyesters such as polyethylene terephthalate (PET), and nylon. The thickness of the outer resin layer is not particularly limited, for example, it is 20 μm or more and 100 μm or less. The case-type outer package is, for example, a metal outer package. Examples of the material constituting the case-type outer package include aluminum and aluminum alloy. In addition, aluminum or aluminum alloy can be plastically processed and the work-hardened material can be used. In addition, the thickness of the case-type outer package is not particularly limited and is selected to obtain the required rigidity. (iv) Battery Examples of the battery in the first embodiment include secondary batteries such as lithium ion secondary batteries. In addition, examples of the use of the battery before being processed by the processing method in the first embodiment include power sources for vehicles such as hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), battery electric vehicles (BEV), gasoline vehicles, and diesel vehicles. It is particularly preferably a battery used as a drive power source for a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV). It may also be a battery used as a power source for a moving body other than a vehicle (e.g., railway, ship, aircraft), or a battery used as a power source for an electrical product such as an information processing device. (2) Processing liquid The processing liquid in the first embodiment contains water and a supporting salt. The supporting salt is used to increase the conductivity of the processing liquid. In addition, the supporting salt generally does not have a function of suppressing the dissolution of the Al terminal. The supporting salt has a cation component and an anion component. Examples of the cation component of the supporting salt include alkali metal ions such as Na and K; alkaline earth metal ions such as Mg and Ca. On the other hand, examples of the anion component of the supporting salt include chloride ions. Specific examples of the supporting salt include NaCl, KCl, MgCl2, and CaCl2. In addition, the processing liquid may contain only one supporting salt or may contain two or more supporting salts. At least a part of the supporting salt is dissolved in water. There is no particular limitation on the concentration of the supporting salt in the treatment liquid. For example, it is 0.01 mol / kg or more and 5.0 mol / kg or less, and can be 0.1 mol / kg or more and 3.0 mol / kg or less. In the first embodiment, the above-mentioned concentration of the supporting salt is defined as the ratio of the number of moles of the supporting salt to the weight of the water contained in the treatment liquid. In addition, as a method for preparing the treatment liquid, for example, a method of dissolving the supporting salt in water can be cited. (3) Immersion process In the immersion process in the first embodiment, the battery including the Al terminal is immersed in the treatment liquid, and the voltage of the battery is reduced by external short-circuiting via the above-mentioned treatment liquid. Specifically, as Figure 2 shown, the treatment liquid 50 is put into the treatment bath 40, and the battery 100 is immersed in the treatment liquid 50. There is no particular limitation on the temperature of the treatment liquid in the immersion process. For example, since the freezing point of brine is about -20°C, the temperature of the treatment liquid is also preferably -20°C or more, more preferably 0°C or more. On the other hand, the temperature of the treatment liquid is, for example, 60°C or less, and can be 40°C or less. In addition, the temperature of the treatment liquid in the immersion process can be the same as the room temperature. There is no particular limitation on the treatment time in the immersion process. From the viewpoint of workability, for example, it is preferably 1 hour or more and 50 hours or less, more preferably 2 hours or more and 25 hours or less. 2. Protective layer formation process The method for treating the battery in the first embodiment may have a protective layer formation process before the above-mentioned immersion process, and the protective layer formation process is a process of forming the above-mentioned protective layer on the above-mentioned surface of the above-mentioned Al terminal. There is no particular limitation on the method for forming the protective layer, and it is appropriately selected according to the type of the protective layer. For specific examples of the method for forming the protective layer, as described above. A-2. Second embodiment The method for treating the battery in the second embodiment has an immersion process, in which a battery including an Al terminal is immersed in a treatment liquid, and the voltage of the battery is reduced by external short-circuiting via the treatment liquid. The treatment liquid contains water and a supporting salt, and the material of the Al terminal is an Al-Mg-Si alloy system or an Al-Ni coating material. Figure 1 (a) and (b) are schematic top views and schematic side views showing the battery in the second embodiment. As Figure 1As shown in (a) and (b), the battery 100 has: an electrode body 10, an outer packaging body 20 that covers the electrode body 10, and terminals 30 (30A, 30B) that are electrically connected to the electrode body 10 and a part of which protrudes from the outer packaging body 20. At least one of the terminal 30A and the terminal 30B is an Al terminal. In Figure 1 (a) and (b), the terminal 30A corresponds to the Al terminal 30X. Figure 7 is a schematic side view illustrating a method for treating a battery in the second embodiment. As Figure 7 shown, a treatment liquid 50 is poured into a treatment bath 40, and the battery 100 is immersed in the treatment liquid 50. The terminals 30A and 30B are electrically connected via the treatment liquid 50, thereby causing an external short circuit and reducing the voltage of the battery 100. In the second embodiment, the material of the Al terminal 30X is an Al-Mg-Si-based alloy or an Al-Ni clad material. According to the second embodiment, since the material of the Al terminal is a specific material, the battery can be deactivated well. Specifically, since the material of the Al terminal is a specific material, deterioration of the Al terminal due to the treatment liquid can be suppressed. Therefore, when the battery is immersed in the treatment liquid, the external short circuit can be maintained, and the battery can be deactivated well. The immersion step in the second embodiment is a step of immersing a battery including an Al terminal in a treatment liquid and reducing the voltage of the battery by an external short circuit via the treatment liquid. In the second embodiment, the material of the Al terminal is an Al-Mg-Si-based alloy or an Al-Ni clad material. The Al-Mg-Si-based alloy is a so-called 6000 series aluminum alloy, which is an aluminum alloy in which Mg (magnesium) and Si (silicon) are added to Al (aluminum) to increase the corrosion resistance. The Al-Mg-Si-based alloy contains at least Al, Mg, and Si, and may further contain one or more of trace metal elements (including semi-metal elements). As trace metal elements, for example, Cu, Mn, Fe, Cr, Ti, B, Zn, and Zr can be cited. In addition, the content of Al in the Al-Mg-Si-based alloy is, for example, 50% by weight or more, and can be 70% by weight or more, and can be 90% by weight or more. The Al-Ni clad material is a clad material having a Ni (nickel) layer on the surface of an Al (aluminum) layer. The Al-Ni clad material may have a Ni layer on one side of the Al layer or may have Ni layers on both sides of the Al layer. In addition, the Al-Ni clad material may be an overlay clad material, an inlay clad material, or an edgelay clad material. Details of the immersion step and the battery in the second embodiment are the same as those described in the first embodiment above, and thus the description thereof is omitted here. B. Battery The battery in the present disclosure is a battery including an Al terminal, and at least a part of the surface of the above Al terminal may have a protective layer that inhibits the dissolution of the above Al terminal into the processing liquid. In addition, the battery in the present disclosure is a battery including an Al terminal, and the material of the above Al terminal may be an Al-Mg-Si alloy or an Al-Ni coated material. According to the present disclosure, by having a protective layer on the surface of the Al terminal or using a specific material as the material of the Al terminal, when the battery is recycled, it becomes a battery that can be deactivated well. Regarding the battery in the present disclosure, it is the same as the content described in the above "A. Battery processing method", so the description here is omitted. The present disclosure is not limited to the above embodiments. The above embodiments are illustrative, and technical solutions having substantially the same configuration as the technical idea described in the claims of the present disclosure and achieving the same effects are included in the technical scope of the present disclosure.

Claims

1. A method for treating a battery, which has an impregnation step, wherein, Immerse a battery including an Al terminal in a treatment liquid, and reduce the voltage of the battery by external short-circuiting via the treatment liquid. The treatment liquid contains water and a supporting salt. At least a part of the surface of the Al terminal has a protective layer that inhibits the dissolution of the Al terminal into the treatment liquid.

2. The method for processing a battery according to claim 1, wherein, Before the immersion step, the method for treating the battery has a protective layer forming step of forming the protective layer on the surface of the Al terminal.

3. The method for treating a battery according to claim 1, wherein, The battery includes: an electrode body, an outer packaging body covering the electrode body, and the Al terminal, where the Al terminal is electrically connected to the electrode body and a part thereof protrudes from the outer packaging body. The protective layer is formed on the surface of the Al terminal located inside the outer packaging body.

4. The method for treating a battery according to claim 1, wherein, The protective layer is an alumina layer.

5. The method for treating a battery according to claim 4, wherein, The alumina layer is a boehmite layer.

6. The method for treating a battery according to claim 1, wherein, The protective layer is a conductive resin layer.

7. The method for treating a battery according to claim 1, wherein, The protective layer is a plating layer.

8. A method for treating a battery, which has an impregnation step, wherein, Immerse a battery including an Al terminal in a treatment liquid, and reduce the voltage of the battery by external short-circuiting via the treatment liquid. The treatment liquid contains water and a supporting salt. The material of the Al terminal is an Al-Mg-Si based alloy or an Al-Ni clad material.

9. A battery is a battery including an Al terminal, and at least a part of the surface of the Al terminal has a protective layer that inhibits the dissolution of the Al terminal into a treatment liquid.

10. The battery according to claim 9, wherein, The battery includes an electrode body, an outer packaging body covering the electrode body, and the Al terminal, where the Al terminal is electrically connected to the electrode body and a part thereof protrudes from the outer packaging body. Viewed from the thickness direction, the protective layer is selectively formed in a region including an end portion on the side of the outer packaging body where the Al terminal is located.

11. A battery is a battery including an Al terminal, and the material of the Al terminal is an Al-Mg-Si based alloy or an Al-Ni clad material.

12. The battery according to claim 9 or claim 11, wherein, The battery has a laminated outer packaging body.

13. The battery according to claim 9 or claim 11, wherein, The battery is a solid battery.

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