Battery processing method and battery processing system

Abstract

The invention relates to a battery processing method and a battery processing system. The main purpose of the present invention is to provide a battery processing method capable of deactivating a battery satisfactorily. The present disclosure solves the above-mentioned problem by providing a battery processing method comprising an immersion step in which a battery including an Al terminal is immersed in a processing liquid, the voltage of the battery is reduced by an external short circuit through the processing liquid, and the voltage of the battery is reduced by an external short circuit through the processing liquid. The treatment liquid contains water, a supporting salt, and an additive that suppresses elution of the Al terminal, and the concentration of the additive in the treatment liquid is equal to or greater than the minimum concentration CMIN at which elution of the Al terminal can be suppressed.

Description

Technical Field

[0001] The present disclosure relates to a method for treating a battery and a battery treatment system. Background Art

[0002] 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 a method for discharging a waste battery, in which at least the positive terminal and the negative terminal of the charged waste battery are immersed in an aqueous solution in which a weak alkali metal salt is dissolved and discharged.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-257849

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2005-347162 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In the recycling of a battery, 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 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 satisfactorily.

[0009] In view of the above actual situation, the present disclosure has been completed, and a main object thereof is to provide a method for treating a battery that can deactivate the battery satisfactorily.

[0010] Means for Solving the Problems

[0011] [1] A method for treating a battery, which 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 containing water, a supporting salt, and an additive that inhibits the elution of the Al terminal, and the concentration of the additive in the treatment liquid being the lowest concentration C that can inhibit the elution of the Al terminal MIN or more.

[0012] [2] The method for treating a battery according to [1], wherein the additive contains, as an anionic component, a phosphoric acid-based anion, a silicic acid-based anion, an imide-based anion, or a carboxylic acid-based anion.

[0013] [3] The battery treatment method according to [2], wherein the phosphoric acid-based anion is a phosphate ion, a phosphite ion, a hypophosphite ion, or a polyphosphate ion.

[0014] [4] The battery treatment method according to [2], wherein the silicic acid-based anion is an orthosilicate ion, a silicate ion, or a polysilicate ion.

[0015] [5] The battery treatment method according to any one of [1] to [4], wherein, in the additive, an alkali metal ion is included as a cation component.

[0016] [6] The battery treatment method according to [5], wherein the alkali metal ion is a potassium ion.

[0017] [7] The battery treatment method according to any one of [1] to [6], wherein the concentration of the additive in the treatment liquid is 0.5 mol / kg or more.

[0018] [8] The battery treatment method according to any one of [1] to [7], wherein the concentration of the additive in the treatment liquid is 1.0 mol / kg or more.

[0019] [9] The battery treatment method according to any one of [1] to [8], wherein, in the impregnation step, the temperature of the treatment liquid is 0°C or more and 60°C or less.

[0020]

[10] The battery treatment method according to any one of [1] to [9], wherein the battery has a laminated outer package.

[0021]

[11] The battery treatment method according to any one of [1] to

[10] , wherein the battery is a solid battery.

[0022]

[12] A battery treatment system, comprising: a treatment bath for treating a battery including an Al terminal with a treatment liquid, the treatment liquid containing water, a supporting salt, and an additive for suppressing the dissolution of the Al terminal; a monitoring device for monitoring the concentration of the additive in the treatment liquid; a determination device for determining the concentration of the additive in the treatment liquid; and a concentration adjustment device for adjusting the concentration of the additive in the treatment liquid, wherein the determination device determines whether the concentration of the additive is above a threshold value based on the concentration of the additive obtained by using the monitoring device, and when the determination device determines that the concentration of the additive is less than the threshold value, the concentration adjustment device inputs the additive into the treatment bath to adjust the concentration of the additive to the lowest concentration C capable of suppressing the dissolution of the Al terminal MINAbove.

[0023]

[13] The processing system for a battery according to

[12] , wherein the monitoring device also monitors the temperature of the processing liquid, and the determination device determines whether the concentration of the additive is above a threshold value based on the concentration of the additive and the temperature of the processing liquid obtained by using the monitoring device.

[0024] Effects of the Invention

[0025] The present disclosure achieves the effect of enabling the battery to be deactivated well. Description of the Drawings

[0026] Figure 1 Schematic top view and schematic side view of the battery of the present disclosure are shown as examples.

[0027] Figure 2 Schematic side view of the method for processing the battery of the present disclosure is shown as an example.

[0028] Figure 3 Schematic cross-sectional view of the electrode body of the present disclosure is shown as an example.

[0029] Figure 4 Explanation diagram of the processing system for the battery of the present disclosure is shown as an example.

[0030] Figure 5 Flowchart of the processing flow of the processing system for the battery of the present disclosure is shown as an example.

[0031] Figure 6 Results of LSV measurement for the battery cells fabricated in Reference Comparative Example 1 are shown.

[0032] Figure 7 Results of LSV measurement for the battery cells fabricated in Comparative Example 1-1, Example 1-1, Example 1-2, and Example 1-3 are shown.

[0033] Figure 8 Results of LSV measurement for the battery cells fabricated in Comparative Example 2-1, Example 2-1, Example 2-2, and Example 2-3 are shown.

[0034] Figure 9 Results of LSV measurement for the battery cells fabricated in Comparative Example 3-1, Comparative Example 3-2, Example 3-1, and Example 3-2 are shown.

[0035] Figure 10 Results of LSV measurement for the battery cells fabricated in Comparative Example 4-1 are shown.

[0036] Figure 11 Coordinate diagram showing the relationship between the concentration of the additive and the current density is shown.

[0037] Figure 12 This is the result of LSV measurement for the battery cell fabricated in Comparative Example 2 for benchmarking.

[0038] Figure 13 This is the result of LSV measurement for the battery cells fabricated in Example 4-1, Example 4-2, Example 5-1, and Example 6-1.

[0039] Explanation of Reference Numerals

[0040] 1... Negative electrode current collector

[0041] 2... Negative electrode active material layer

[0042] 3... Electrolyte layer

[0043] 4... Positive electrode active material layer

[0044] 5... Positive electrode current collector

[0045] 10... Electrode body

[0046] 20... Outer package body

[0047] 30... Terminal

[0048] 40... Treatment bath

[0049] 50... Treatment liquid

[0050] 100... Battery Detailed Description of the Invention

[0051] Hereinafter, the treatment method of the battery and the battery treatment system of the present disclosure will be described in detail.

[0052] A. Treatment Method of Battery

[0053] Figure 1 (a) and (b) are schematic top views and schematic side views illustrating the battery of the present disclosure. As Figure 1 (a) and (b) show, the battery 100 includes: an electrode body 10, an outer package body 20 covering the electrode body 10, and terminals 30 (30A, 30B) that are electrically connected to the electrode body 10 and partially exposed from the outer package body 20. At least one of the terminal 30A and the terminal 30B is an Al terminal.

[0054] Figure 2 This is a schematic side view illustrating the treatment method of the battery of the present disclosure. 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. The terminals 30A and 30B are electrically connected through the treatment liquid 50, thereby causing an external short circuit and reducing the voltage of the battery 100. In the present disclosure, the treatment liquid 50 contains an additive that inhibits the dissolution of the Al terminal at a prescribed concentration.

[0055] According to the present disclosure, the treatment liquid contains an additive that inhibits the dissolution of Al terminals at a prescribed concentration, so that the battery can be deactivated well. As described above, when recycling the 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 (dismantling) process can be carried out safely. As a method for deactivating the 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 Al terminals, the Al terminals may be deteriorated by the treatment liquid, and it is difficult to deactivate the battery well. For example, due to the treatment liquid, corrosion (dissolution) of the Al terminals occurs. If the Al terminals exposed from the outer package body slip off, the reduction of the residual voltage due to the external short circuit may no longer occur, or the reduction rate may decrease significantly.

[0056] In contrast, in the present disclosure, an additive that inhibits the dissolution of Al terminals is used. Al (Al ions) dissolved from the Al terminals into the treatment liquid combines with the anions of the additive present in the treatment liquid and accumulates on the surface of the Al terminals. Thereby, a passivation film is formed on the surface of the Al terminals. The passivation film functions as a protective film, and thus the dissolution rate of Al dissolved from the Al terminals into the treatment liquid can be reduced. By immersing the battery in a treatment liquid containing such an additive, an external short circuit can be maintained, and the battery can be deactivated well.

[0057] The method for treating a battery according to the present disclosure has an immersion step of immersing a battery including Al terminals in a treatment liquid and reducing the voltage of the battery through an external short circuit via the treatment liquid.

[0058] 1. Treatment liquid

[0059] The treatment liquid according to the present disclosure contains water, a supporting salt, and an additive that inhibits the dissolution of Al terminals.

[0060] The supporting salt is used to increase the conductivity of the treatment liquid. In addition, the supporting salt generally does not have a function of inhibiting the dissolution of Al terminals. The supporting salt has a cation component and an anion component. As the cation component of the supporting salt, for example, alkali metal ions such as Na and K; alkaline earth metal ions such as Mg and Ca can be cited. On the other hand, as the anion component of the supporting salt, for example, chloride ions can be cited. As a specific example of the supporting salt, NaCl, KCl, MgCl2, and CaCl2 can be cited. In addition, the treatment liquid may contain only one supporting salt or may contain two or more supporting salts.

[0061] 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 it can be 0.1 mol / kg or more and 3.0 mol / kg or less. In the present disclosure, the above 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.

[0062] The additive is used to inhibit the dissolution of Al terminals. In addition, the additive has a cationic component and an anionic component. The anionic component of the additive binds to Al (Al ions) dissolved from the Al terminal into the treatment liquid and accumulates on the surface of the Al terminal. As the anionic component of the additive, for example, phosphoric acid-based anions, silicic acid-based anions, imide-based anions, and carboxylic acid-based anions can be cited.

[0063] The phosphoric acid-based anion is an anion containing phosphorus (P) and oxygen (O). As the phosphoric acid-based anion, for example, phosphate ions (PO4 3- ), phosphite ions (HPO3 2- ), hypophosphite ions (H2PO2 - ) can be cited. In addition, the phosphoric acid-based anion can be a polyphosphate ion. The polyphosphate ion is an ion having two or more phosphorus (P). As the polyphosphate ion, for example, P2O7 4- , P3O9 3- , P3O 10 5- .

[0064] The silicic acid-based anion is an anion containing silicon (Si) and oxygen (O). As the silicic acid-based anion, for example, orthosilicate ions (SiO4 4- ), silicate ions (SiO3 2- ) can be cited. In addition, the silicic acid-based anion can be a polysilicate ion. The polysilicate ion is an ion having two or more silicon (Si). As the polysilicate ion, for example, Si2O7 6- can be cited.

[0065] As the imide-based anion, for example, bis(trifluoromethanesulfonyl)imide ions (TFSI ions, (CF3SO2)2N - ), bis(sulfonyl)imide ions (FSI ions, (FSO2)2N - ) can be cited. In addition, as the carboxylic acid-based anion, for example, acetate ions (CH3COO - ) can be cited.

[0066] Examples of the cationic components as additives include alkali metal ions such as Na and K; alkaline earth metal ions such as Mg and Ca. Among them, the cationic component of the additive is preferably a potassium ion. This is because the solubility of the additive in water is increased.

[0067] Specific examples of the additive include K3PO4, Na3PO4, Mg3(PO4)2, Ca3(PO4)2; K4P2O7, Na4P2O7, Mg2P2O7, Ca2P2O7; K4SiO4, Na4SiO4, Mg2SiO4, Ca2SiO4; K2SiO3, Na2SiO2; K(CF3SO2)2N, Na(CF3SO2)2N; K(FSO2)2N, Na(FSO2)2N; CH3COOK, CH3COONa, Mg(CH3COO)2, Ca(CH3COO)2. The treatment liquid may contain only one additive or may contain two or more additives.

[0068] At least a part of the additive dissolves in water. The concentration of the additive in the treatment liquid is the lowest concentration C that can inhibit the dissolution of the Al terminal. MIN Above. If the concentration of the additive is too low, a passivation film is not formed on the surface of the Al terminal. On the contrary, the dissolution of the Al terminal may sometimes be promoted. Therefore, the lowest concentration that can inhibit the dissolution of the Al terminal is defined as C. MIN The concentration of the additive in the treatment liquid is adjusted to be the lowest concentration C or above. MIN Above. The lowest concentration C MIN Varies depending on the type of the additive. Therefore, the lowest concentration C is determined as follows. MIN : By using the additive used in the treatment liquid, a preliminary experiment of changing its concentration is carried out and compared with the treatment liquid without using the additive, thereby determining the lowest concentration C. MIN In addition, the lowest concentration C MIN Is also affected by the temperature of the treatment liquid in the dipping process. Therefore, the above preliminary experiment also needs to consider the temperature of the treatment liquid. In addition, as the above preliminary experiment, it is preferable to carry out linear sweep voltammetry (LSV) measurement as described in the examples below.

[0069] The concentration of the additive in the treatment liquid is, for example, 0.5 mol / kg or more and may be 1.0 mol / kg or more. On the other hand, the concentration of the additive in the treatment liquid is not particularly limited as long as it is a concentration that can inhibit the dissolution of the Al terminal, for example, 10 mol / kg or less. In the present disclosure, the above concentration of the additive is defined as the ratio of the number of moles of the additive to the weight of the water contained in the treatment liquid.

[0070] The treatment liquid may contain an acid or a base as needed. By adding an acid or a base, for example, the solubility of the additive can be increased. In addition, as a method for preparing the treatment liquid, for example, a method of dissolving a supporting salt and an additive in water can be cited.

[0071] 2. Battery

[0072] As Figure 1 As 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.

[0073] In the present disclosure, a unit composed of an electrode body, an outer packaging body, and a pair of terminals is sometimes referred to as a "battery cell". The battery treated by the treatment method of the present disclosure may have one battery cell or may have two or more battery cells.

[0074] (1) Terminal

[0075] The battery of the present disclosure 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 preferable 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 relative to all the metal components is, for example, 50% by weight or more, may be 70% by weight or more, and may be 90% by weight or more. As the material of the Al terminal, for example, aluminum and aluminum alloy can be cited.

[0076] 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 deterioration effect of the treatment liquid on 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, may be 3 mm or less, may be 1 mm or less, may be 0.8 mm or less, and may be 0.6 mm or less. On the other hand, the thickness of the Al terminal is, for example, 0.1 mm or more.

[0077] (2) Electrode body

[0078] The electrode body of the present disclosure 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 this order in the thickness direction.

[0079] Figure 3 Taking (a) and (b) as examples, a schematic cross-sectional view of the electrode body of the present disclosure is shown. Figure 3The electrode body 10 shown in (a) sequentially includes a negative current collector 1, a negative active material layer 2, an electrolyte layer 3, a positive active material layer 4, and a positive current collector 5 in the thickness direction (z direction). Additionally, the negative current collector 1 has a negative electrode tab 1t for connecting to a negative terminal (not shown), and the positive current collector 5 has a positive electrode tab 5t for connecting to a positive terminal (not shown).

[0080] Figure 3 The electrode body 10 shown in (b) includes: a negative current collector 1; a negative active material layer 2x, an electrolyte layer 3x, a positive active material layer 4x, and a positive current collector 5x sequentially disposed in the thickness direction (z direction) starting from one surface of the negative current collector 1; and a negative active material layer 2y, an electrolyte layer 3y, a positive active material layer 4y, and a positive current collector 5y sequentially disposed in the thickness direction (z direction) starting from the other surface of the negative current collector 1.

[0081] Figure 3 In (a) and (b), the positive electrode tab 5t and the negative electrode tab 1t are disposed 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 disposed on the same side surface of the electrode body, constituting a so-called single-tab structure. Additionally, as shown in Figure 3 (a) and (b), the electrode body 10 may be a single-tab type. Additionally, although not particularly shown, the electrode body may be a wound type. Additionally, a unit composed of a positive active material layer, an electrolyte layer, and a negative active material layer is sometimes referred to as a "power generation unit". The electrode body of the present disclosure may have one power generation unit or may have a plurality of power generation units. The plurality of power generation units are usually stacked in the thickness direction.

[0082] The positive active material layer contains at least a positive active material. The positive active material layer may further contain at least one of an electrolyte, a conductive material, and a binder. As the positive 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, LiNi 0.8 Co 0.15 Al 0.05 O2 and other rock salt layered type active materials; LiMn2O4 and other spinel type active materials; LiFePO4 and other olivine type active materials. The shape of the positive active material is, for example, particulate.

[0083] 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, there is no particular limitation on the liquid electrolyte, 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.

[0084] 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.

[0085] 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. Regarding 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 (for example, 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.

[0086] The positive electrode current collector conducts the current collection 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 conducts the current collection 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.

[0087] (3) Outer packaging body

[0088] The outer package of the present disclosure can be a laminated outer package or a shell-type outer package. The laminated outer package, also known as a bag-type outer package, is an outer package using a laminated film. The laminated outer package 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. Examples of the thermoplastic resin include polyolefins such as polyethylene and polypropylene, polystyrene, and polyvinyl chloride. There is no particular limitation on the thickness of the inner resin layer, for example, it is 30 μm or more and 150 μm or less.

[0089] The metal layer functions as a barrier layer. Examples of the metal used for the metal layer include aluminum, aluminum alloy, and stainless steel. There is no particular limitation on the thickness of the metal layer, for example, it is 20 μm or more and 100 μm or less. In addition, based on the metal layer, the laminated outer package can have an outer resin layer on the opposite side of 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. There is no particular limitation on the thickness of the outer resin layer, for example, it is 20 μm or more and 100 μm or less.

[0090] The shell-type outer package is, for example, a metal outer package. Examples of the material constituting the shell-type outer package include aluminum and aluminum alloy. In addition, aluminum or aluminum alloy can be plastically processed and a work-hardened material can be used. In addition, there is no particular limitation on the thickness of the shell-type outer package, and it is selected to obtain the required rigidity.

[0091] (4) Battery

[0092] Examples of the battery of the present disclosure include secondary batteries such as lithium-ion secondary batteries. In addition, as the use of the battery before being processed by the processing method of the present disclosure, for example, it can be used as a power source 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 driving power source for a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV). It can also be a battery used as a power source for a moving body other than a vehicle (such as a railway, a ship, an aircraft), or a battery used as a power source for an electrical product such as an information processing device.

[0093] 3. Impregnation process

[0094] The impregnation process of the present disclosure immerses a battery including an Al terminal in a treatment liquid, and reduces the voltage of the battery by an external short circuit through the 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.

[0095] There is no particular limitation on the temperature of the treatment liquid in the impregnation 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 higher, more preferably 0°C or higher. On the other hand, the temperature of the treatment liquid is, for example, 60°C or lower, and can be 40°C or lower. In addition, the temperature of the treatment liquid in the impregnation process can be the same as the room temperature.

[0096] There is no particular limitation on the treatment time in the impregnation 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.

[0097] B. Battery treatment system

[0098] As Figure 4 shown, the battery treatment system of the present disclosure includes a treatment bath, a monitoring device, a determination device, and a concentration adjustment device. The treatment bath is a device for treating the battery. The monitoring device monitors the concentration of the additive in the treatment liquid. The determination device determines the concentration of the additive in the treatment liquid. The concentration adjustment device adjusts the concentration of the additive in the treatment liquid. Further, the determination device determines whether the concentration of the additive is above a threshold value based on the concentration of the additive obtained by using the monitoring device. When the determination device determines that the concentration of the additive is less than the threshold value, the concentration adjustment device inputs the additive into the treatment bath and adjusts the concentration of the additive to the lowest concentration C that can inhibit the dissolution of the Al terminal MIN or more.

[0099] According to the present disclosure, by adjusting the concentration of the additive in the treatment liquid to the lowest concentration C that can inhibit the dissolution of the Al terminal MIN or more, the battery can be deactivated well.

[0100] 1. Treatment bath

[0101] The treatment bath of the present disclosure is a device for treating a battery containing an Al terminal with a treatment liquid containing water, a supporting salt, and an additive that inhibits the dissolution of the above Al terminal. As shown in the above Figure 2 , by putting the treatment liquid 50 into the treatment bath 40 and immersing the battery 100 in the treatment liquid 50, the battery 100 can be treated with the treatment liquid 50.

[0102] The treatment bath is not particularly limited as long as it is a device that can accommodate the battery and the treatment liquid. In addition, for the battery and the additive, it is the same as the content described in the above "A. Battery treatment method", so the description here is omitted.

[0103] 2. Monitoring device

[0104] The monitoring device of the present disclosure is configured to monitor the concentration of the above-mentioned additive in the above-mentioned processing liquid. As a monitoring device for monitoring the concentration of the additive, for example, a liquid concentration meter can be cited. As the types of liquid concentration meters, for example, vibration type (ultrasonic type), viscosity type, spectroscopic type, electromagnetic induction type can be cited. For example, by combining ultrasonic waves and conductivity measurement, the liquid concentration meter can accurately measure the concentration of the additive in the processing liquid.

[0105] The monitoring device can be configured to monitor the temperature of the processing liquid. By monitoring the temperature of the processing liquid, the determination device described later can accurately determine whether the concentration of the additive in the processing liquid is above the threshold value. As a monitoring device for monitoring the temperature of the processing liquid, for example, a thermometer can be cited. As the types of thermometers, for example, bimetal type, thermocouple type, semiconductor type can be cited.

[0106] 3. Determination device

[0107] The determination device of the present disclosure is configured to determine the concentration of the above-mentioned additive in the above-mentioned processing liquid. Specifically, the determination device is configured to determine whether the concentration of the above-mentioned additive in the above-mentioned processing liquid is above the threshold value based on the concentration of the above-mentioned additive obtained by using the above-mentioned monitoring device.

[0108] The determination device includes a CPU (Central Processing Unit), a memory, and an input / output port for inputting and outputting various signals. The memory includes, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and a rewritable non-volatile memory. The CPU executes the program stored in the memory to perform various controls.

[0109] The determination device has at least an acquisition unit and a determination unit as processing blocks for realizing its functions. The acquisition unit is set to acquire the concentration of the additive from the monitoring device. The determination unit determines whether the concentration of the additive is above the threshold value based on the concentration of the additive acquired by the acquisition unit. The threshold value can be set, for example, as the lowest concentration C determined based on the concentration map made by prior measurement MIN , or can also be set as the value obtained by adding the remaining part to the lowest concentration C MIN .

[0110] When the monitoring device monitors the temperature of the processing liquid, the acquisition unit can be set to acquire the temperature of the processing liquid from the monitoring device. In this case, the determination unit preferably determines whether the concentration of the additive is above the threshold value based on the concentration of the additive and the temperature of the processing liquid acquired by the acquisition unit. The threshold value can be set, for example, as the lowest concentration C determined based on the concentration-temperature map made by prior measurement MIN , or can also be set as the value obtained by adding the remaining part to the lowest concentration C MIN .

[0111] 4. Concentration adjustment device

[0112] The concentration adjustment device of the present disclosure is configured as follows: when the determination device determines that the concentration of the above additive is less than the threshold value, the above additive is put into the above treatment bath, and the concentration of the above additive is adjusted to the lowest concentration C that can inhibit the dissolution of the above Al terminal MIN Above.

[0113] The concentration adjustment device can add the additive to the treatment liquid in a solid state, or can add the additive to the treatment liquid in a state of a high-concentration treatment liquid. The high-concentration treatment liquid is a treatment liquid in which the additive is dissolved at a high concentration. The high-concentration treatment liquid is a treatment liquid with a higher concentration of the additive than the treatment liquid in the treatment bath

[0114] 5. Battery treatment system

[0115] The battery treatment system of the present disclosure may include a temperature adjustment device configured to adjust the temperature in the treatment bath based on the temperature of the treatment liquid obtained by the monitoring device. As the temperature adjustment device, for example, a heating body that heats the treatment bath or a heating body that heats the treatment liquid can be cited. In addition, the battery treatment system of the present disclosure may include a stirring device configured to stir the treatment liquid in the treatment bath. By providing the stirring device, it is possible to equalize the temperature of the treatment liquid or to uniformly disperse the additive added to the treatment bath by the concentration adjustment device

[0116] Figure 5 is a flowchart showing the treatment process of the battery treatment system of the present disclosure. As Figure 5 shown, in step S1, the determination device obtains the concentration D of the additive in the treatment liquid from the monitoring device a . Then, in step S2, the determination device determines whether the concentration D of the additive a is the concentration D set as the threshold value b or more. When the concentration D of the additive a is the concentration D set as the threshold value b or more, the treatment process ends. On the other hand, when the concentration D of the additive a is less than the concentration D set as the threshold value b , in step S3, the concentration adjustment device puts the additive into the treatment liquid, and then returns to step S1. Alternatively, although not particularly shown, the treatment process may end after the additive is put in. The above treatment process is preferably repeated at regular intervals

[0117] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are illustrative, and technical solutions having substantially the same configurations 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.

[0118] Example

[0119] [Reference Comparative Example 1]

[0120] A Batch Cell for battery evaluation (SB1A, manufactured by EC Frontier) was prepared, and battery cells were fabricated under the following conditions.

[0121] Working electrode: Al foil

[0122] Counter electrode: Ni foil

[0123] Reference electrode: Silver-silver chloride electrode (manufactured by BAS)

[0124] Electrolyte: 3.5 wt% aqueous KCl solution

[0125] For the fabricated battery cells, linear sweep voltammetry (LSV) measurements were performed. The measurement conditions are as follows.

[0126] Scan rate: 1 mV / s

[0127] Measurement temperature: 25 °C (LSV measurement was performed after maintaining the battery cell in a thermostatic bath for 8 hours or more)

[0128] Scan range: from OCP to 1.0 V vs. Ag / AgCl (1.2 V vs. SHE)

[0129] The results of the LSV measurements are shown in Figure 6 . As Figure 6 shown, in Reference Comparative Example 1, it was confirmed that the current density slowly increased from the start of the measurement to around 0.7 V. The increase in the current density was due to the dissolution of Al.

[0130] [Comparative Example 1-1 and Examples 1-1, 1-2, 1-3]

[0131] A 3.5 wt% aqueous KCl solution was prepared, and K2SiO3 (additive) was further added and stirred. The concentration of K2SiO3 was 0.1 mol / kg, 0.5 mol / kg, 1.0 mol / kg, and 2.0 mol / kg based on the weight of H2O in the aqueous KCl solution, respectively. After stirring, it was left standing overnight in a thermostatic bath at 25 °C to obtain an electrolyte. Except for using the obtained electrolyte, battery cells were fabricated in the same manner as in Reference Comparative Example 1, and LSV measurements were performed.

[0132] The results of the LSV measurements are shown inFigure 7 As Figure 7 (a) shows, in Comparative Example 1-1, it was confirmed that starting from around 0 V, the current density increased sharply. In addition, comparing Figure 7 (a) with Figure 6 , it was found that the current density increased in Comparative Example 1-1 compared to Reference Comparative Example 1. It is speculated that this is because the concentration of K2SiO3 is low and a passivation film cannot be formed on the Al foil, but the use of K2SiO3 increases the conductivity of the treatment solution. In addition, it is considered that due to the sharp dissolution of Al, the accumulation of hydroxides may occur, and pores may be generated in the Al foil. On the other hand, as Figure 7 (b), (c), (d) show, in Examples 1-1, 1-2, and 1-3, almost no increase in the current density was confirmed. In addition, comparing Figure 7 (b), (c), (d) with Figure 6 , it was confirmed that the dissolution of Al was suppressed in Examples 1-1, 1-2, and 1-3 compared to Reference Comparative Example 1.

[0133] [Comparative Example 2-1 and Examples 2-1, 2-2, 2-3]

[0134] A 3.5 wt% aqueous KCl solution was prepared, and K3PO4 (additive) was further added and stirred. The concentration of K3PO4 was 0.1 mol / kg, 0.5 mol / kg, 1.0 mol / kg, and 2.0 mol / kg based on the weight of H2O in the aqueous KCl solution. After stirring, it was left standing overnight in a constant temperature bath at 25 °C to obtain an electrolytic solution. Except for using the obtained electrolytic solution, a battery cell was fabricated in the same manner as in Reference Comparative Example 1, and LSV measurement was performed.

[0135] The results of the LSV measurement are shown in Figure 8 . As Figure 8 (a) shows, in Comparative Example 2-1, it was confirmed that starting from around 0.2 V, the current density increased sharply. In addition, comparing Figure 8 (a) with Figure 6 , it was found that the current density also increased in Comparative Example 2-1 compared to Reference Comparative Example 1. It is speculated that this is because the concentration of K3PO4 is low and a passivation film cannot be formed on the Al foil, but the use of K3PO4 increases the conductivity of the treatment solution. On the other hand, as Figure 8 (b), (c), (d) show, in Examples 2-1, 2-2, and 2-3, almost no increase in the current density was confirmed. In addition, comparing Figure 8 (b), (c), (d) with Figure 6 , it was confirmed that the dissolution of Al was suppressed in Examples 2-1, 2-2, and 2-3 compared to Reference Comparative Example 1.

[0136] [Comparative Examples 3-1, 3-2 and Examples 3-1, 3-2]

[0137] A 3.5 wt% aqueous KCl solution was prepared, and K4P2O7 (additive) was further added and stirred. The concentration of K4P2O7 was 0.1 mol / kg, 0.5 mol / kg, 1.0 mol / kg, and 2.0 mol / kg based on the weight of H2O in the aqueous KCl solution, respectively. After stirring, it was left standing overnight in a constant temperature bath at 25 °C to obtain an electrolyte solution. Except for using the obtained electrolyte solution, a battery cell was fabricated in the same manner as in Reference Comparative Example 1, and LSV measurement was performed.

[0138] The results of the LSV measurement are shown in Figure 9 . As shown in Figure 9 (a) and (b), in Comparative Examples 2-1 and 2-2, it was confirmed that the current density increased sharply starting from around -0.2 V. In addition, comparing Figure 9 (a) and (b) with Figure 6 , it was also confirmed that the current density increased in Comparative Examples 2-1 and 2-2 compared to Reference Comparative Example 1. It is speculated that this is because the concentration of K4P2O7 is low and a passivation film cannot be formed on the Al foil, but the use of K4P2O7 increases the conductivity of the treatment solution. On the other hand, as shown in Figure 9 (c) and (d), in Examples 3-1 and 3-2, a slight increase in the current density was confirmed. However, comparing Figure 9 (c) and (d) with Figure 6 , it was confirmed that the dissolution of Al was suppressed in Examples 3-1 and 3-2 compared to Reference Comparative Example 1 (especially, almost no dissolution of Al occurred around 0.5 V).

[0139] [Comparative Example 4-1]

[0140] A 3.5 wt% aqueous KCl solution was prepared, and K2SO4 (additive) was further added and stirred. The concentration of K2SO4 was set to the saturation concentration. After stirring, it was left standing overnight in a constant temperature bath at 25 °C to obtain an electrolyte solution. Except for using the obtained electrolyte solution, a battery cell was fabricated in the same manner as in Reference Comparative Example 1, and LSV measurement was performed.

[0141] The results of the LSV measurement are shown in Figure 10 . As shown in Figure 10 , in Comparative Example 4-1, it was confirmed that the current density increased slowly from around -0.1 V to around 0.6 V. In addition, comparing Figure 10 with Figure 6 , it was confirmed that the current density increased in Comparative Example 4-1 compared to Reference Comparative Example 1. It is speculated that this is because K2SO4 cannot form a passivation film on the Al foil and the use of K2SO4 increases the conductivity of the treatment solution.

[0142] The results of the above-described respective examples, comparative examples, and reference comparative example 1 are shown in Table 1.

[0143] [Table 1]

[0144]

[0145] In addition, the relationship between the concentration of the additive and the current density is shown in Figure 11 . In Figure 11 , the current density at 0.5 V was substantially plotted. On the other hand, for example, as shown in Figure 7 (a), when a peak of the current density was confirmed at a potential lower than 0.5 V, the maximum value of the current density (Max in Table 1) was plotted. As shown in Figure 11 , by adding a prescribed additive at a prescribed concentration, it was confirmed that the dissolution of Al was suppressed. In particular, K2SiO3 was able to significantly suppress the dissolution of Al. In addition, Figure 11 the value of the current density of reference comparative example 1 shown in MIN was the reference for determining the lowest concentration C

[0146] [Reference Comparative Example 2]

[0147] Except that the measurement temperature of the LSV measurement was changed to 0 °C (the cell unit was held in a thermostat for 8 hours or more and then the LSV measurement was carried out), the LSV measurement was carried out in the same manner as in reference comparative example 1. The results are shown in Figure 12 and Table 2. As shown in Figure 12 and Table 2, in reference comparative example 2, it was confirmed that the current density increased rapidly starting from around 0.2 V.

[0148] [Examples 4-1, 4-2, 5-1, 6-1]

[0149] Except that an electrolytic solution prepared in the same manner as in comparative example 1-1, example 1-1, example 2-1, and comparative example 3-2 was used, a cell unit was fabricated in the same manner as in reference comparative example 2, and the LSV measurement was carried out. The results are shown in Figure 13 and Table 2.

[0150] [Table 2]

[0151]

[0152] As shown in Figure 13 (a), in example 4-1, a slight increase in the current density was confirmed. However, comparing Figure 13 (a) with Figure 12 , it was confirmed that in example 4-1, the dissolution of Al was suppressed compared to reference comparative example 2 (in particular, near 0.2 V, almost no dissolution of Al occurred). In addition, asFigure 13 As shown in (b), (c), and (d), in Examples 4-2, 5-1, and 6-1, almost no increase in current density was confirmed. Additionally, Figure 13 Comparing (b), (c), and (d) with Figure 12 it was confirmed that in Examples 4-2, 5-1, and 6-1, the dissolution of Al was suppressed compared to Reference Comparative Example 2.

[0153] Comparing Figure 12 with the above-mentioned Figure 6 since no additives were used in Reference Comparative Example 1 and Reference Comparative Example 2, the dissolution of Al occurred at both 0 °C and 25 °C. On the other hand, comparing Figure 13 (a) with the above-mentioned Figure 7 (a), it was confirmed that even when the concentration of K2SiO3 was low, the dissolution of Al could be suppressed by controlling the temperature of the treatment solution. Additionally, comparing Figure 13 (b) with the above-mentioned Figure 7 (b), K2SiO3 could significantly suppress the dissolution of Al at both 0 °C and 25 °C. Additionally, comparing Figure 13 (c) with the above-mentioned Figure 8 (b), K3PO4 could significantly suppress the dissolution of Al at both 0 °C and 25 °C. On the other hand, comparing Figure 13 (d) with the above-mentioned Figure 9 (b), it was confirmed that even when the concentration of K4P2O7 was low, the dissolution of Al could be suppressed by controlling the temperature of the treatment solution.

Claims

1. A method for treating a battery, comprising an immersion step, wherein: A battery including an Al terminal is immersed in a treatment solution, and a voltage of the battery is reduced by external short circuiting via the treatment solution. The treatment solution contains water, a supporting salt, and an additive for suppressing the elution of the Al terminal. The concentration of the additive in the treatment solution is the minimum concentration C that can suppress the elution of the Al terminal. MIN above.

2. The battery processing method according to claim 1, wherein: The additive contains, as an anion component, a phosphate anion, a silicate anion, an imide anion or a carboxylate anion.

3. The battery processing method according to claim 2, wherein: The phosphate anion is a phosphate ion, a phosphite ion, a hypophosphite ion or a polyphosphate ion.

4. The battery processing method according to claim 2, wherein: The silicic acid anions are orthosilicate ions, silicate ions or polysilicate ions.

5. The battery processing method according to claim 2, wherein: The additive contains alkali metal ions as cationic components.

6. The battery processing method according to claim 5, wherein: The alkali metal ion is a potassium ion.

7. The battery processing method according to claim 1, wherein: The concentration of the additive in the treatment liquid is 0.5 mol / kg or more.

8. The battery processing method according to claim 1, wherein: The concentration of the additive in the treatment liquid is 1.0 mol / kg or more.

9. The battery processing method according to claim 1, wherein: In the immersion step, the temperature of the treatment liquid is 0° C. or higher and 60° C. or lower.

10. The battery processing method according to claim 1, wherein: The battery has a laminated outer package.

11. The battery processing method according to claim 1, wherein: The battery is a solid battery.

12. A battery processing system comprising: a treatment bath for treating a battery including an Al terminal with a treatment solution, the treatment solution containing water, a supporting salt, and an additive for inhibiting the elution of the Al terminal; a monitoring device for monitoring the concentration of the additive in the treatment liquid; a determination device for determining the concentration of the additive in the treatment liquid; and a concentration adjusting device for adjusting the concentration of the additive in the treatment liquid, wherein the determination device determines whether the concentration of the additive is above a threshold value based on the concentration of the additive obtained by the monitoring device, When the determination device determines that the concentration of the additive is less than the threshold value, the concentration adjustment device adds the additive to the treatment bath to adjust the concentration of the additive to the minimum concentration C that can suppress the dissolution of the Al terminal. MIN above.

13. The battery processing system according to claim 12, wherein: The monitoring device also monitors the temperature of the treatment liquid. The determination device determines whether the concentration of the additive is equal to or higher than a threshold value based on the concentration of the additive obtained by the monitoring device and the temperature of the treatment liquid.

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