Battery processing method and battery processing system

Abstract

To provide a battery processing method capable of preferably deactivating a battery.SOLUTION: A battery processing method of the present disclosure includes an immersion step of immersing a battery including an Al terminal in process liquid to reduce a voltage of the battery by external short circuit via the process liquid. The process liquid contains water, supporting salt, and an additive for suppressing elution of the Al terminal. A concentration of the additive in the process liquid is equal to or greater than a minimum concentration CMIN with which elution of the AI terminal can be suppressed. By providing such a battery processing method, the above problem is solved.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a battery processing method and a battery processing system.

Background Art

[0002] A battery usually has terminals for extracting electricity from an electrode body which is a power generation element. For example, Patent Document 1 discloses a battery module having a laminated exterior flat battery having a positive terminal lead and a negative terminal lead, and discloses that the positive terminal lead is made of aluminum. Further, 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 an alkali metal weak acid salt is dissolved for discharging.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recycling a battery, it is desired to reduce the residual voltage of the battery and deactivate the battery. As a method for deactivating a battery, for example, a method of externally short-circuiting by immersing the battery in a processing liquid (for example, salt water) can be mentioned. In a battery including an aluminum terminal (Al terminal), the Al terminal may be deteriorated by the processing liquid, and it may be difficult to deactivate the battery satisfactorily.

[0005] The present disclosure has been made in view of the above circumstances, and the main object thereof is to provide a battery processing method capable of deactivating a battery satisfactorily.

Means for Solving the Problems

[0006] [1] A battery containing an Al terminal is immersed in a treatment liquid, and the voltage of the battery is reduced by an external short circuit through the treatment liquid, having an immersion step. The treatment liquid contains water, a supporting salt, and an additive that suppresses the elution of the Al terminal. The concentration of the additive in the treatment liquid is the lowest concentration C capable of suppressing the elution of the Al terminal. MIN The above is a method for treating a battery.

[0007] [2] The additive contains, as an anion component, a phosphate-based anion, a silicate-based anion, an imide-based anion, or a carboxylic acid-based anion, the method for treating a battery according to [1].

[0008] [3] The phosphate-based anion is a phosphate ion, a phosphite ion, a hypophosphite ion, or a polyphosphate ion, the method for treating a battery according to [2].

[0009] [4] The silicate-based anion is an orthosilicate ion, a metasilicate ion, or a polysilicate ion, the method for treating a battery according to [2].

[0010] [5] The additive contains, as a cation component, an alkali metal ion, the method for treating a battery according to any one of [1] to [4].

[0011] [6] The alkali metal ion is a potassium ion, the method for treating a battery according to [5].

[0012] [7] The concentration of the additive in the treatment liquid is 0.5 mol / kg or more, the method for treating a battery according to any one of [1] to [6].

[0013] [8] The method for treating a battery 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.

[0014] [9] The method for treating a battery according to any one of [1] to [8], wherein in the immersion step, the temperature of the treatment liquid is 0°C or higher and 60°C or lower.

[0015]

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

[0016]

[11] The method for treating a battery according to any one of [1] to

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

[0017]

[12] A treatment bath for treating a battery containing an Al terminal with a treatment liquid containing water, a supporting salt, and an additive for suppressing 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, A concentration adjustment device for adjusting the concentration of the additive in the treatment liquid, A battery system comprising: 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, When the determination device determines that the concentration of the additive is less than the threshold value, the concentration adjustment device injects the additive into the treatment bath to adjust the concentration of the additive to the lowest concentration C capable of suppressing the elution of the Al terminal MIN or higher. A battery treatment system.

[0018]

[13] The monitoring device further monitors the temperature of the treatment liquid. The determination device is the battery processing system according to

[12] , which determines whether the concentration of the additive is equal to or higher than a threshold value based on the concentration of the additive and the temperature of the processing solution obtained by the monitoring device.

Effect of the Invention

[0019] In the present disclosure, there is an effect that the battery can be deactivated well.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0021] Hereinafter, a method for treating a battery and a battery treatment system in the present disclosure will be described in detail.

[0022] A. Method for treating a battery Figs. 1(a) and (b) are a schematic plan view and a schematic side view illustrating a battery in the present disclosure. As shown in Figs. 1(a) and (b), the battery 100 includes an electrode body 10, an exterior body 20 covering the electrode body 10, and terminals 30 (30A, 30B) electrically connected to the electrode body 10 and partially exposed from the exterior body 20. At least one of the terminals 30A and 30B is an Al terminal.

[0023] Fig. 2 is a schematic side view illustrating a method for treating a battery in the present disclosure. As shown in Fig. 2, a treatment liquid 50 is introduced into a treatment bath 40, and the battery 100 is immersed in the treatment liquid 50. By causing the terminals 30A and 30B to conduct through the treatment liquid 50, an external short circuit occurs and the voltage of the battery 100 decreases. In the present disclosure, the treatment liquid 50 contains an additive that suppresses the elution of the Al terminal at a predetermined concentration.

[0024] According to the present disclosure, since the treatment liquid contains an additive that suppresses the elution of Al terminals at a predetermined concentration, 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 the battery disassembly process can be performed safely. As a method for deactivating a battery, there is a method of externally short-circuiting by immersing the battery in a treatment liquid (for example, salt water). In a battery including Al terminals, it may be difficult to deactivate the battery well because the Al terminals are deteriorated by the treatment liquid. For example, when corrosion (elution) of the Al terminals occurs due to the treatment liquid and the Al terminals exposed from the exterior body slip off, the decrease in the residual voltage due to the external short circuit may not occur or the rate of decrease may be significantly reduced.

[0025] In contrast, in the present disclosure, an additive that suppresses the elution of Al terminals is used. Al (Al ions) eluted from the Al terminals into the treatment liquid binds to the anions of the additive present in the treatment liquid and deposits on the surface of the Al terminals. Thereby, a passive film is formed on the surface of the Al terminals. By functioning as a protective film, the elution rate at which Al elutes 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.

[0026] The immersion method of the battery in the present disclosure includes an immersion step of immersing a battery including Al terminals in a treatment liquid and reducing the voltage of the battery by an external short circuit through the treatment liquid.

[0027] 1. Treatment liquid The treatment liquid in the present disclosure contains water, a supporting salt, and an additive that suppresses the elution of Al terminals.

[0028] Support salts are used to improve the conductivity of the treatment liquid. Also, support salts usually do not have the function of suppressing the elution of Al terminals. Support salts have a cation component and an anion component. Examples of the cation component of the support 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 support salt include chloride ions. Specific examples of the treatment liquid include NaCl, KCl, MgCl2, and CaCl2. Also, the treatment liquid may contain only one type of support salt or may contain two or more types of support salts.

[0029] At least a part of the support salt is dissolved in water. The concentration of the support salt in the treatment liquid is not particularly limited, but for example, it is 0.01 mol / kg or more and 5.0 mol / kg or less, and may be 0.1 mol / kg or more and 3.0 mol / kg or less. In the present disclosure, the above concentration of the support salt is defined as the ratio of the number of moles of the support salt to the weight of water contained in the treatment liquid.

[0030] Additives are used to suppress the elution of Al terminals. Also, additives have a cation component and an anion component. The anion component of the additive binds to Al (Al ions) eluted from the Al terminal into the treatment liquid and deposits on the surface of the Al terminal. Examples of the anion component of the additive include phosphate anions, silicate anions, imide anions, and carboxylic acid anions.

[0031] Phosphate anions are anions containing phosphorus (P) and oxygen (O). Examples of phosphate anions include phosphate ions (PO4 3- ), phosphite ions (HPO3 2- ), hypophosphite ions (H2PO2 - ). Also, the phosphate anion may be a polyphosphate ion. A polyphosphate ion is an ion having two or more phosphorus (P). Examples of polyphosphate ions include P2O7 4- , P3O9 3- , P3O 10 5- .

[0032] Silicate anions are anions containing silicon (Si) and oxygen (O). Examples of silicate anions include orthosilicate ions (SiO4 4- ), metasilicate ions (SiO3 2- ). Also, the silicate anion may be a polysilicate ion. A polysilicate ion is an ion having two or more silicon (Si). Examples of polysilicate ions include Si2O7 6- .

[0033] Examples of imide anions include bis(trifluoromethanesulfonyl)imide ion (TFSI ion, (CF3SO2)2N - ), bis(sulfonyl)imide ion (FSI ion, (FSO2)2N - ). Also, examples of carboxylic acid anions include acetate ion (CH3COO - ).

[0034] Examples of the cation component of the additive include alkali metal ions such as Na and K; alkaline earth metal ions such as Mg and Ca. Among them, the cation component of the additive is preferably a potassium ion. This is because the solubility of the additive in water is improved.

[0035] 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 kind of additive or may contain two or more kinds of additives.

[0036] At least a part of the additive is dissolved in water. The concentration of the additive in the treatment liquid is the minimum concentration C that can suppress the elution of the Al terminal. MIN is as follows. If the concentration of the additive is too low, a passive film is not formed on the surface of the Al terminal, and conversely, the elution of the Al terminal may be promoted. Therefore, the minimum concentration that can suppress the elution of the Al terminal is defined as C MIN , and the concentration of the additive in the treatment liquid is adjusted to be equal to or higher than the minimum concentration C MIN . Since the minimum concentration C MIN varies depending on the type of additive, a preliminary experiment is performed using the additive used in the treatment liquid and changing its concentration, and by comparing it with the treatment liquid without the additive, the minimum concentration C MIN is specified. In addition, since the minimum concentration C MIN is also affected by the temperature of the treatment liquid in the immersion process, the above preliminary experiment also takes into account the temperature of the treatment liquid. Also, as the above preliminary experiment, it is preferable to perform linear sweep voltammetry (LSV) measurement as described in the examples described later.

[0037] 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 can suppress the elution of the Al terminal, but is, 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 water contained in the treatment liquid.

[0038] The treatment liquid may contain an acid or an alkali as necessary. By adding an acid or an alkali, for example, the solubility of the additive can be improved. In addition, examples of the method for preparing the treatment liquid include a method of dissolving a supporting salt and an additive in water.

[0039] 2. Battery As shown in FIGS. 1(a) and 1(b), the battery 100 generally includes an electrode body 10, an exterior 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 exterior body 20. At least one of the terminals 30A and 30B is an Al terminal.

[0040] In the present disclosure, a unit composed of an electrode body, an exterior body, and a pair of terminals may be referred to as a "cell". The battery processed by the processing method in the present disclosure may have one cell or two or more cells.

[0041] (1) Terminals The battery in the present disclosure generally has a positive electrode terminal and a negative electrode terminal. At least one of the positive electrode terminal and the negative electrode terminal is an Al terminal. Among them, it is preferable that at least the positive electrode 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 ratio of aluminum to all metal components is, for example, 50% by weight or more, and may be 70% by weight or more, or may be 90% by weight or more. Examples of the material of the Al terminal include aluminum and aluminum alloy.

[0042] The shape of the Al terminal is not particularly limited. Also, the thickness of the Al terminal is not particularly limited, but the thinner the Al terminal, the greater the influence of the deterioration of the Al terminal by the processing liquid. 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, and may be 3 mm or less, 1 mm or less, 0.8 mm or less, or 0.6 mm or less. On the other hand, the thickness of the Al terminal is, for example, 0.1 mm or more.

[0043] (2) Electrode body The electrode body in the present disclosure functions as a power generation element of a battery. The electrode body usually has a negative current collector, a negative electrode active material layer, an electrolyte layer, a positive electrode active material layer, and a positive current collector in this order in the thickness direction.

[0044] Figs. 3(a) and (b) are schematic cross-sectional views illustrating the electrode body in the present disclosure. The electrode body 10 shown in Fig. 3(a) has a negative current collector 1, a negative electrode active material layer 2, an electrolyte layer 3, a positive electrode active material layer 4, and a positive current collector 5 in this order in the thickness direction (z direction). Further, the negative current collector 1 has a negative tab 1t for connection to a negative terminal (not shown), and the positive current collector 5 has a positive tab 5t for connection to a positive terminal (not shown).

[0045] The electrode body 10 shown in Fig. 3(b) has a negative current collector 1, a negative electrode active material layer 2x, an electrolyte layer 3x, a positive electrode active material layer 4x, and a positive current collector 5x arranged in this order in the thickness direction (z direction) from one surface of the negative 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 current collector 5y arranged in this order in the thickness direction (z direction) from the other surface of the negative current collector 1.

[0046] In Figs. 3(a) and (b), the positive tab 5t and the negative tab 1t are arranged to face each other on the side surface of the electrode body 10, forming a so-called double tab structure. On the other hand, although not particularly shown, the positive tab and the negative tab may be arranged on the same side surface of the electrode body, forming a so-called single tab structure. Further, as shown in Figs. 3(a) and (b), the electrode body 10 may be of a single leaf type. Also, although not particularly shown, the electrode body may be of 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 may be referred to as a "power generation unit". The electrode body in 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 laminated in the thickness direction.

[0047] 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. Examples of the positive electrode active material include oxide active materials. Examples of the oxide active material include, 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 layer structured active materials, spinel type active materials such as LiMn2O4, olivine type active materials such as LiFePO4, etc. The shape of the positive electrode active material is, for example, particulate.

[0048] The electrolyte may be a solid electrolyte or a liquid electrolyte (electrolyte solution). The solid electrolyte may 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 because of its high ionic conductivity. On the other hand, the liquid electrolyte is not particularly limited, and known electrolytes can be adopted. Examples of the conductive material include, for example, carbon materials. Examples of the binder include, for example, rubber-based binders and fluoride-based binders.

[0049] 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. Examples of the negative electrode active material include metal active materials such as Li, Si, Sn, etc., carbon active materials such as graphite, and oxide active materials such as Li4Ti5O 12 etc.

[0050] 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 may be a solid electrolyte or a liquid electrolyte. The electrolyte is the same as described above. The electrolyte layer may be a solid electrolyte layer containing a solid electrolyte. Further, the solid electrolyte is preferably a sulfide solid electrolyte. Generally, a battery having a solid electrolyte layer containing an inorganic solid electrolyte is called a solid battery. The solid battery may be a semi-solid battery or an all-solid battery. In the present disclosure, a 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, an all-solid battery is a battery in which the electrolyte layer has only an inorganic solid electrolyte as an electrolyte.

[0051] The positive electrode current collector conducts current collection for the positive electrode active material layer. Examples of the material of the positive electrode current collector include metals such as aluminum, SUS, and nickel. Examples of the shape of the positive electrode current collector include a foil shape. The positive electrode current collector usually has a positive electrode tab for connection to the positive electrode terminal. The negative electrode current collector conducts current collection for the negative electrode active material layer. Examples of the material of the negative electrode current collector include metals such as copper, SUS, and nickel. Examples of the shape of the negative electrode current collector include a foil shape. The negative electrode current collector usually has a negative electrode tab for connection to the negative electrode terminal.

[0052] (3) Outer package The outer package in the present disclosure may be a laminate type outer package or a case type outer package. The laminate type outer package is also called a pouch type outer package and is an outer package using a laminate film. The laminate type 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. The thickness of the inner resin layer is not particularly limited, but is, for example, 30 μm or more and 150 μm or less.

[0053] 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, but for example, it is 20 μm or more and 100 μm or less. Further, the laminate-type exterior body may have an outer resin layer on the side opposite to the inner resin layer with respect to the metal 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, but for example, it is 20 μm or more and 100 μm or less.

[0054] The case-type exterior body is, for example, a metal exterior body. Examples of the material constituting the case-type exterior body include aluminum and aluminum alloy. Further, plastic working may be performed on aluminum or an aluminum alloy, and a work-hardened material may be used. The thickness of the case-type exterior body is not particularly limited and is selected to obtain a desired rigidity.

[0055] (4) Battery Examples of the battery in the present disclosure include secondary batteries such as lithium ion secondary batteries. Further, examples of the use of the battery before being processed by the processing method in the present disclosure include power sources for vehicles such as hybrid vehicles (HEV), plug-in hybrid vehicles (PHEV), battery electric vehicles (BEV), gasoline vehicles, and diesel vehicles. In particular, it is preferably a battery that has been used as a drive power source for a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), or a battery electric vehicle (BEV). It may be a battery that has been used as a power source for a moving body other than a vehicle (for example, a railway, a ship, an aircraft), or a battery that has been used as a power source for an electrical product such as an information processing device.

[0056] 3. Immersion method In the immersion process in the present disclosure, a battery including an Al terminal is immersed in a treatment liquid, and the voltage of the battery is decreased by an external short circuit through the treatment liquid. Specifically, as shown in FIG. 2, the treatment liquid 50 is introduced into the treatment bath 40, and the battery 100 is immersed in the treatment liquid 50.

[0057] The temperature of the treatment liquid in the immersion process is not particularly limited. For example, since the freezing point of brine is about -20°C, the temperature of the treatment liquid is 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 may be 40°C or lower. Also, the temperature of the treatment liquid in the immersion process may be the same as room temperature.

[0058] The treatment time in the immersion process is not particularly limited, but 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.

[0059] B. Battery treatment system As shown in FIG. 4, the battery treatment system in the present disclosure includes a treatment bath, a monitoring device, a determination device, and a concentration adjustment device. The treatment bath is a facility 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 equal to or higher than 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 injects the additive into the treatment bath to adjust the concentration of the additive to the minimum concentration C MIN or higher that can suppress the elution of the Al terminal.

[0060] According to the present disclosure, by adjusting the concentration of the additive in the treatment liquid to the minimum concentration C MIN or higher that can suppress the elution of the Al terminal, the battery can be deactivated well.

[0061] 1. Treatment bath The treatment bath in the present disclosure is a facility for treating a battery including an Al terminal with a treatment liquid containing water, a supporting salt, and an additive that suppresses elution of the above Al terminal. As shown in FIG. 2 described above, by introducing 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.

[0062] The treatment bath is not particularly limited as long as it is a facility capable of accommodating a battery and a treatment liquid. Also, regarding the battery and the additive, since they are the same as those described in the above "A. Battery treatment method", the description here is omitted.

[0063] 2. Monitoring device The monitoring device in the present disclosure is configured to monitor the concentration of the above additive in the above treatment liquid. Examples of the monitoring device for monitoring the concentration of the additive include a liquid densitometer. Examples of the types of liquid densitometers include a vibration type (ultrasonic type), a viscosity type, a spectroscopic type, and an electromagnetic induction type. For example, by combining ultrasonic waves and conductivity measurement, the liquid densitometer can accurately measure the concentration of the additive in the treatment liquid.

[0064] The monitoring device may be configured to monitor the temperature of the treatment liquid. By monitoring the temperature of the treatment liquid, the determination device described later can accurately determine whether the concentration of the additive in the treatment liquid is equal to or higher than a threshold value. Examples of the monitoring device for monitoring the temperature of the treatment liquid include a thermometer. Examples of the types of thermometers include a bimetal type, a thermocouple type, and a semiconductor type.

[0065] 3. Determination device The determination device in the present disclosure is configured to determine the concentration of the above additive in the above treatment liquid. Specifically, the determination device is configured to determine whether the concentration of the above additive in the above treatment liquid is equal to or higher than a threshold value based on the concentration of the above additive obtained by the above monitoring device.

[0066] 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. By the CPU executing the program stored in the memory, various controls are executed.

[0067] 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 equal to or higher than a threshold value based on the concentration of the additive acquired by the acquisition unit. The threshold value is, for example, the minimum concentration C specified based on a concentration map created by prior measurement. MIN It may be set to, MIN or a value obtained by adding a surplus to the minimum concentration C.

[0068] When the monitoring device monitors the temperature of the processing liquid, the acquisition unit may be set to acquire the temperature of the processing liquid from the monitoring device. In this case, it is preferable that the determination unit determines whether the concentration of the additive is equal to or higher than a threshold value based on the concentration of the additive and the temperature of the processing liquid acquired by the acquisition unit. The threshold value is, for example, the minimum concentration C specified based on a concentration-temperature map created by prior measurement. MIN It may be set to, MIN or a value obtained by adding a surplus to the minimum concentration C.

[0069] 4. Concentration adjustment device When the above determination device determines that the concentration of the above additive is less than the threshold value, the concentration adjustment device in the present disclosure is configured to introduce the above additive into the above processing bath and adjust the concentration of the above additive to at least the minimum concentration C capable of suppressing the elution of the above Al terminal. MIN or higher.

[0070] The concentration adjusting device may add the additive to the treatment liquid in a solid state, or may add the additive to the treatment liquid in a high-concentration treatment liquid in which the additive is dissolved at a high concentration. The high-concentration treatment liquid is a treatment liquid having a higher concentration of the additive than the treatment liquid in the treatment bath.

[0071] 5. Battery handling system 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. Examples of the temperature adjustment device include a heating body that heats the treatment bath and a heating body that heats the treatment liquid. The battery treatment system of the present disclosure may also include an agitation device configured to agitate the treatment liquid in the treatment bath. By providing the agitation device, the temperature of the treatment liquid can be made uniform, and the additives added to the treatment bath by the concentration adjustment device can be uniformly dispersed.

[0072] 5 is a flowchart illustrating a process flow of the battery treatment system according to the present disclosure. As shown in FIG. 5, in step S1, the determination device receives the concentration D a Then, in step S2, the determination device obtains the additive concentration D a is the concentration D b Determine whether the additive concentration is greater than or equal to D. a is the concentration D b If it is equal to or greater than the concentration of the additive, the process flow ends. a is the concentration D b If the concentration is less than 100%, in step S3, the concentration adjusting device adds an additive to the treatment liquid, and then the process returns to step S1. Alternatively, although not shown in the figure, the process flow may be terminated after adding the additive. The above process flow is preferably repeated at predetermined intervals, for example.

[0073] The present disclosure is not limited to the above embodiments. The above embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits the same operational effects is included in the technical scope of the present disclosure.

Example

[0074] [Reference Comparative Example 1] A batch cell for battery evaluation (SB1A, manufactured by Easy Frontier) was prepared, and cells were fabricated under the following conditions. Working electrode: Al foil Counter electrode: Ni foil Reference electrode: Silver / silver chloride electrode (manufactured by BAS) Electrolyte: 3.5 wt% aqueous KCl solution

[0075] Linear sweep voltammetry (LSV) measurements were performed on the fabricated cells. The measurement conditions were as follows. Sweep rate: 1 mV / s Measurement temperature: 25°C (LSV measurement was carried out after holding the cell in a thermostatic bath for 8 hours or more) Sweep range: From OCP to 1.0 V vs. Ag / AgCl (1.2 V vs. SHE)

[0076] The results of the LSV measurements are shown in Figure 6. As shown in Figure 6, in Reference Comparative Example 1, it was confirmed that the current density gradually increased from the start of the measurement to around 0.7 V. The increase in the current density is due to the elution of Al.

[0077] [Comparative Example 1-1 and Examples 1-1, 1-2, 1-3] A 3.5 wt% aqueous KCl solution was prepared, and further, K2SiO3 (additive) was 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, respectively, based on the weight of H2O in the aqueous KCl solution. After stirring, it was left standing overnight in a 25°C thermostatic bath to obtain an electrolyte. Cells were fabricated and LSV measurements were performed in the same manner as in Reference Comparative Example 1, except that the obtained electrolyte was used.

[0078] The results of the LSV measurement are shown in Fig. 7. As shown in Fig. 7(a), in Comparative Example 1-1, it was confirmed that the current density increased rapidly from around 0 V. Further, comparing Fig. 7(a) and Fig. 6, the current density of Comparative Example 1-1 was higher than that of Reference Comparative Example 1. This is presumably because the concentration of K2SiO3 was low and a passive film could not be formed on the Al foil, but the conductivity of the treatment solution was improved by K2SiO3. In addition, due to the rapid progress of Al elution, the possibility of hydroxide deposition and the possibility of holes in the Al foil are considered. On the other hand, as shown in Figs. 7(b), (c), and (d), in Examples 1-1, 1-2, and 1-3, almost no increase in the current density was confirmed. Further, comparing Figs. 7(b), (c), and (d) with Fig. 6, it was confirmed that the elution of Al was suppressed in Examples 1-1, 1-2, and 1-3 compared to Reference Comparative Example 1.

[0079] [Comparative Example 2-1 and Examples 2-1, 2-2, 2-3] An aqueous solution of 3.5 wt% KCl was prepared, and further, K3PO4 (additive) was added and stirred. The concentration of K3PO4 was set to 0.1 mol / kg, 0.5 mol / kg, 1.0 mol / kg, and 2.0 mol / kg, respectively, 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. A cell was fabricated in the same manner as in Reference Comparative Example 1 except that the obtained electrolytic solution was used, and LSV measurement was performed.

[0080] The results of the LSV measurement are shown in Fig. 8. As shown in Fig. 8(a), in Comparative Example 2-1, it was confirmed that the current density increased rapidly from around 0.2 V. Further, comparing Fig. 8(a) and Fig. 6, the current density of Comparative Example 2-1 was higher than that of Reference Comparative Example 1. This is presumably because the concentration of K3PO4 was low and a passive film could not be formed on the Al foil, but the conductivity of the treatment liquid was improved by K3PO4. On the other hand, as shown in Figs. 8(b), (c), and (d), in Examples 2-1, 2-2, and 2-3, almost no increase in the current density was confirmed. Further, comparing Figs. 8(b), (c), and (d) with Fig. 6, it was confirmed that in Examples 2-1, 2-2, and 2-3, the elution of Al was suppressed compared to Reference Comparative Example 1.

[0081] [Comparative Examples 3-1, 3-2 and Examples 3-1, 3-2] An aqueous solution of 3.5 wt% KCl was prepared, and further K4P2O7 (additive) was 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, respectively, based on the weight of H2O in the aqueous KCl solution. After stirring, it was left standing in a constant temperature bath at 25 °C overnight to obtain an electrolytic solution. A cell was fabricated in the same manner as in Reference Comparative Example 1 except that the obtained electrolytic solution was used, and LSV measurement was performed.

[0082] The results of the LSV measurement are shown in Fig. 9. As shown in Figs. 9(a) and (b), in Comparative Example 2-1 and Comparative Example 2-2, it was confirmed that the current density increased rapidly from around -0.2 V. Further, comparing Figs. 9(a) and (b) with Fig. 6, the current density of Comparative Example 2-1 and Comparative Example 2-2 was higher than that of Reference Comparative Example 1. This is presumably because the concentration of K4P2O7 was low and a passive film could not be formed on the Al foil, but the conductivity of the treatment liquid was improved by K4P2O7. On the other hand, as shown in Figs. 9(c) and (d), in Examples 3-1 and 3-2, a slight increase in the current density was confirmed. However, comparing Figs. 9(c) and (d) with Fig. 6, it was confirmed that in Examples 3-1 and 3-2, the elution of Al was suppressed compared to Reference Comparative Example 1 (particularly, almost no elution of Al occurred around 0.5 V).

[0083] [Comparative Example 4-1] An aqueous KCl solution of 3.5% by weight was prepared, and further K2SO4 (additive) was 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 electrolytic solution. A cell was fabricated in the same manner as in Reference Comparative Example 1 except that the obtained electrolytic solution was used, and LSV measurement was performed.

[0084] The results of the LSV measurement are shown in FIG. 10. As shown in FIG. 10, in Comparative Example 4-1, it was confirmed that the current density gradually increased from around -0.1 V to around 0.6 V. Further, comparing FIG. 10 and FIG. 6, the current density in Comparative Example 4-1 was increased compared to Reference Comparative Example 1. This is presumably because K2SO4 cannot form a passive film on the Al foil, and it is presumed that the conductivity of the treatment liquid was improved by K2SO4.

[0085] The results of the above-described examples, comparative examples, and Reference Comparative Example 1 are shown in Table 1.

[0086]

Table 1

[0087] In addition, the relationship between the concentration of the additive and the current density is shown in FIG. 11. In FIG. 11, basically, the current density at 0.5 V was plotted. On the other hand, for example, as shown in FIG. 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 FIG. 11, it was confirmed that the elution of Al was suppressed by adding a predetermined additive at a predetermined concentration. In particular, K2SiO3 was able to significantly suppress the elution of Al. Further, the value of the current density of Reference Comparative Example 1 shown in FIG. 11 serves as a reference for specifying the lowest concentration C MIN to be a reference.

[0088] [Reference Comparative Example 2] LSV measurements were carried out in the same manner as in Reference Comparative Example 1, except that the measurement temperature for the LSV measurement was changed to 0 °C (the LSV measurement was performed after holding the cell in a thermostatic bath for 8 hours or more). The results are shown in FIG. 12 and Table 2. As shown in FIG. 12 and Table 2, in Reference Comparative Example 2, it was confirmed that the current density increased rapidly from around 0.2 V.

[0089] [Examples 4-1, 4-2, 5-1, 6-1] A cell was fabricated and LSV measurements were carried out in the same manner as in Reference Comparative Example 2, except that the electrolytic solution prepared in the same way as in Comparative Example 1-1, Example 1-1, Example 2-1 and Comparative Example 3-2 was used. The results are shown in FIG. 13 and Table 2.

[0090]

Table 2

[0091] As shown in FIG. 13(a), in Example 4-1, a slight increase in the current density was confirmed. However, when comparing FIG. 13(a) with FIG. 12, it was confirmed that in Example 4-1, the elution of Al was suppressed as compared with Reference Comparative Example 2 (particularly, almost no elution of Al occurred around 0.2 V). Also, as shown in FIGS. 13(b), (c), and (d), in Examples 4-2, 5-1, and 6-1, an increase in the current density was hardly confirmed. Further, when comparing FIGS. 13(b), (c), and (d) with FIG. 12, it was confirmed that in Examples 4-2, 5-1, and 6-1, the elution of Al was suppressed as compared with Reference Comparative Example 2.

[0092] When comparing FIG. 12 with the above-mentioned FIG. 6, in Reference Comparative Example 1 and Reference Comparative Example 2, since no additive was used, elution of Al occurred at both 0°C and 25°C. On the other hand, when comparing FIG. 13(a) with the above-mentioned FIG. 7(a), it was confirmed that even when the concentration of K2SiO3 was low, elution of Al could be suppressed by controlling the temperature of the treatment liquid. Also, when comparing FIG. 13(b) with the above-mentioned FIG. 7(b), K2SiO3 was able to significantly suppress the elution of Al at both 0°C and 25°C. Further, when comparing FIG. 13(c) with the above-mentioned FIG. 8(b), K3PO4 was able to significantly suppress the elution of Al at both 0°C and 25°C. On the other hand, when comparing FIG. 13(d) with the above-mentioned FIG. 9(b), it was confirmed that even when the concentration of K4P2O7 was low, elution of Al could be suppressed by controlling the temperature of the treatment liquid.

Explanation of Reference Signs

[0093] 1…Negative electrode current collector 2…Negative electrode active material layer 3…Electrolyte layer 4…Positive electrode active material layer 5…Positive electrode current collector 10…Electrode body 20…Outer package 30…Terminal 40…Treatment bath 50…Treatment liquid 100…Battery

Claims

1. A battery containing an Al terminal is immersed in a treatment liquid, and has an immersion step of reducing the voltage of the battery by an external short circuit through the treatment liquid, The treatment liquid contains water, a supporting salt, and an additive that suppresses the elution of the Al terminal, The concentration of the additive in the treatment liquid is the minimum concentration C capable of suppressing the elution of the Al terminal ＭＩＮ or higher, a method for treating a battery.

2. The battery treatment method according to claim 1, wherein the additive contains a phosphate-based anion, a silicate-based anion, an imide-based anion, or a carboxylic acid-based anion as an anion component.

3. The battery treatment method according to claim 2, wherein the phosphate-based anion is a phosphate ion, a phosphite ion, a hypophosphite ion, or a polyphosphate ion.

4. The battery treatment method according to claim 2, wherein the silicate-based anion is an orthosilicate ion, a metasilicate ion, or a polysilicate ion.

5. The battery treatment method according to claim 2, wherein the additive contains an alkali metal ion as a cation component.

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

7. The battery treatment 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 treatment 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 treatment 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 treatment method according to claim 1, wherein the battery has a laminate-type exterior body.

11. The battery treatment method according to claim 1, wherein the battery is a solid battery.

12. A treatment bath for treating a battery containing an Al terminal with a treatment liquid containing water, a supporting salt, and an additive that suppresses 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, A concentration adjustment device for adjusting the concentration of the additive in the treatment liquid, A battery system comprising: 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. 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 minimum concentration C that can suppress the elution of the Al terminal. ＭＩＮ A battery processing system that adjusts to the above.

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

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