JP2014127417A - Method for collecting and reusing negative electrode active material of lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reusing a negative electrode active material of a lithium ion battery in which a negative electrode active material layer is collected from a negative electrode and can be reused as the negative electrode coated again (a negative electrode active material layer coated and formed on a current collector).SOLUTION: A method for reusing a negative electrode active material layer can be accomplished which includes: a step (1) in which a negative electrode having the negative electrode active material layer containing a nonaqueous binder and a current collector is immersed into an aqueous solution having temperature higher than 50°C; a step (2) in which the exfoliated negative electrode active material layer is collected; and a step (3) in which the collected negative electrode active material layer is stuck to the current collector again.

Description

  The present invention relates to a method for recovering and reusing a negative electrode active material of a lithium ion battery (hereinafter also referred to as LIB).

  Conventional lithium-ion battery (LIB) recycling technology is limited to technology that completely destroys the battery, peels off the electrode active material layer from the current collector using strong acid, etc., and collects rare metal elements as minerals. It was.

  When the current collector also uses a strong acid, the current collector is dissolved by an acid or at least significantly deteriorated, so that electronic conduction cannot be expected and refining must be performed.

  In the method described in Patent Document 1, the negative electrode current collector is dissolved in an acid, and the electrode material is separated and recovered. Alternatively, it is described that the electrode material is skipped by performing a treatment such as heating to collect the current collector.

JP-A-10-255862

  However, in the prior art including Patent Document 1, since it cannot be reused as a coated electrode (electrode active material layer coated / formed on a current collector), from the viewpoint of recycling, cost and environmental impact There was a problem that it was not advantageous.

  Therefore, the present invention collects a negative electrode active material layer from a negative electrode such as used LIB, and reuses it again as a coated negative electrode (a negative electrode active material layer coated / formed on a current collector). An object of the present invention is to provide a method for reusing a negative electrode active material of LIB. In the recycling method of the present invention, in addition to the used LIB, the negative electrode material applied during the production of the negative electrode and the negative electrode material, and the unassembled defective product generated in the assembly process are not yet used. The negative electrode used is the target.

  The purpose is to immerse a negative electrode such as used LIB in an aqueous solution heated to a predetermined temperature range, recover the peeled negative electrode active material layer, and collect the recovered negative electrode active material layer again. And a method of reusing a negative electrode active material layer including a step of attaching to a body.

  According to the present invention, since the negative electrode active material layer and the current collector can be separated using an aqueous solution, the composition of the negative electrode active material layer can be recovered with almost no change. For this reason, after drying the negative electrode active material layer, it can be slurried by adding a viscosity adjusting solvent (for example, NMP (N-methyl-2-pyrrolidone)) and stirring with a homogenizer, and can be applied to the negative electrode current collector. . Thereby, it can reuse as a negative electrode.

  In addition, since no strong acid or strong alkali is used and no solid waste is generated, an environmentally friendly and inexpensive rechargeable battery can be supplied.

Schematic sectional view showing the basic configuration (internal configuration) of a laminated lithium ion secondary battery (laminated flat) produced in Examples and Comparative Examples as used LIBs that can be applied to the recycling method of the present invention It is. FIG. 2 is a perspective view schematically showing an appearance of a laminated lithium ion secondary battery (laminated flat) produced in Examples and Comparative Examples, which are used LIBs that can be applied to the recycling method of the present invention. is there. It is the schematic of the negative electrode peeling apparatus used in the Example etc. It is the schematic of the other negative electrode peeling apparatus used in the Example etc. It is the schematic of the further another negative electrode peeling apparatus used in the Example etc.

  Hereinafter, typical embodiments of the electrode reuse method of a lithium ion battery (LIB) of the present invention will be described in detail with reference to the drawings.

(1) Overall structure of the battery The reusable LIB is not particularly limited. For example, when the LIB is distinguished by its form / structure, it can be applied to any conventionally known form / structure, such as a wound (cylindrical) battery or a stacked (flat) battery.

  In the following description using the drawings, a description will be given by taking a laminated flat LIB as a typical LIB as an example. However, the technical scope of the present embodiment is not limited to the following forms.

  FIG. 1 is a schematic diagram illustrating a basic configuration of a stacked flat LIB (also simply referred to as a stacked battery) that can be recycled as a used LIB that can be applied to any of the following embodiments. . As shown in FIG. 1, the regenerative / reusable stacked battery 1 has a substantially rectangular power generation element 2 in which a charge / discharge reaction actually proceeds is sealed inside a laminate sheet 14 that is an exterior body. It has a structure. Here, in the power generating element 2, the negative electrode in which the negative electrode active material layer 7 is disposed on one surface of the negative electrode current collector 5, the electrolyte layer 11, and the positive electrode active material layer 9 are disposed on both surfaces of the positive electrode current collector 6. It has a configuration in which a positive electrode is laminated. Specifically, the negative electrode, the electrolyte layer, and the positive electrode are laminated in this order so that one negative electrode active material layer 7 and the positive electrode active material layer 9 adjacent thereto face each other with the electrolyte layer 11 therebetween.

  Thereby, the adjacent negative electrode, electrolyte layer, and positive electrode constitute one single cell layer 13. Therefore, it can be said that the stacked battery 1 has a configuration in which a plurality of single battery layers 13 are stacked and electrically connected in parallel. In addition, although the negative electrode active material layer 7 is arrange | positioned only at one side in the outermost layer negative electrode collector located in both outermost layers of the electric power generation element 2, an active material layer may be provided in both surfaces. That is, instead of using a current collector dedicated to the outermost layer provided with an active material layer only on one side, a current collector having an active material layer on both sides may be used as it is as an outermost current collector. In addition, the arrangement of the positive electrode and the negative electrode is reversed from that in FIG. 1 so that the outermost positive electrode current collector is positioned on both outermost layers of the power generation element 2, and the outermost positive electrode current collector is disposed on one or both surfaces of the outermost layer positive electrode current collector. A positive electrode active material layer may be disposed.

  The negative electrode current collector 5 and the positive electrode current collector 6 are each provided with a negative electrode tab 3 and a positive electrode tab 4 that are electrically connected to each electrode (negative electrode and positive electrode), and are sandwiched between end portions of the laminate sheet 14. 14 is derived to the outside. The negative electrode tab 3 and the positive electrode tab 4 are ultrasonic welded or resistance welded to the negative electrode current collector 5 and the positive electrode current collector 6 of each electrode, respectively, via a negative electrode lead and a positive electrode lead (not shown) as necessary. May be attached.

  Also, from the viewpoint of reuse, the stacked (flat) battery 1 is relatively easy to handle as a disassembled electrode (current collector + electrode active material layer) rather than a wound type (cylindrical). This is advantageous in that

  In addition, about each member which comprises LIB which can be reused, it does not restrict | limit in particular, A conventionally well-known thing can be utilized. Hereinafter, each member will be described.

(A) Current collector The positive and negative electrode current collectors 6 and 5 are made of a conductive material. The sizes of the positive and negative electrode current collectors 6 and 5 are determined according to the intended use of the LIB. For example, if it is used for a large LIB that requires a high energy density, a current collector having a large area is used. The thickness of the positive and negative electrode current collectors 6 and 5 is not particularly limited. The thickness of the positive and negative electrode current collectors 6 and 5 is usually about 1 to 100 μm.

  There is no restriction | limiting in particular in the material which comprises the positive / negative electrode collectors 6 and 5. FIG. For example, a metal or a resin in which a conductive filler is added to a conductive polymer material or a non-conductive polymer material can be employed. Specifically, examples of the metal include aluminum, nickel, iron, stainless steel, titanium, and copper. In addition to these, a clad material of nickel and aluminum, a clad material of copper and aluminum, or a plating material of a combination of these metals can be preferably used. Moreover, the foil by which aluminum is coat | covered on the metal surface may be sufficient. Of these, aluminum, stainless steel, and copper are preferable from the viewpoints of electronic conductivity and battery operating potential.

  Examples of the conductive polymer material include polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene, polyphenylene vinylene, polyacrylonitrile, and polyoxadiazole. Since such a conductive polymer material has sufficient conductivity without adding a conductive filler, it is advantageous in terms of facilitating the manufacturing process or reducing the weight of the current collector.

  Non-conductive polymer materials include, for example, polyethylene, polypropylene, polyethylene terephthalate, polyether nitrile, polyimide, polyamideimide, polyamide, polytetrafluoroethylene, styrene-butadiene rubber, polyacrylonitrile, polymethyl acrylate, polymethyl methacrylate, Examples thereof include polyvinyl chloride, polyvinylidene fluoride, and polystyrene. Such a non-conductive polymer material may have excellent potential resistance or solvent resistance.

  A conductive filler may be added to the conductive polymer material or the non-conductive polymer material as necessary. In particular, when the resin used as the base material of the current collector is made of only a non-conductive polymer, a conductive filler is inevitably necessary to impart conductivity to the resin. The conductive filler can be used without particular limitation as long as it is a substance having conductivity. For example, metals, conductive carbon, etc. are mentioned as a material excellent in electroconductivity, electric potential resistance, or lithium ion barrier | blocking property. The metal is not particularly limited, but at least one metal selected from the group consisting of Ni, Ti, Al, Cu, Pt, Fe, Cr, Sn, Zn, In, Sb, and K, or these metals It is preferable to contain an alloy or metal oxide containing. The conductive carbon is not particularly limited, and examples thereof include acetylene black, vulcan, black pearl, carbon nanofiber, ketjen black, carbon nanotube, carbon nanohorn, carbon nanoballoon, and fullerene. The amount of the conductive filler added is not particularly limited as long as it can provide sufficient conductivity to the positive and negative electrode current collectors 6 and 5, and is generally about 5 to 35% by mass.

  Moreover, as a material of the outermost layer current collector, for example, a metal or a conductive polymer can be adopted. From the viewpoint of ease of taking out electricity, a metal material is preferably used. Specifically, metal materials, such as aluminum, nickel, iron, stainless steel, titanium, copper, are mentioned, for example. In addition to these, a clad material of nickel and aluminum, a clad material of copper and aluminum, or a plating material of a combination of these metals can be preferably used. Moreover, the foil by which aluminum is coat | covered on the metal surface may be sufficient. Of these, aluminum and copper are preferable from the viewpoints of electron conductivity and battery operating potential.

(B) Active material layer The positive and negative electrode active material layers 9 and 7 contain an active material, and further contain other additives as required.

The positive electrode active material layer 9 includes a positive electrode active material. Examples of the positive electrode active material include LiMn ₂ O ₄ , LiCoO ₂ , LiNiO ₂ , Li (Ni—Co—Mn) O ₂ , LiFePO _4, and a part of these transition metals substituted with other elements. Lithium-transition metal composite oxides, lithium-transition metal phosphate compounds, lithium-transition metal sulfate compounds, and the like. In some cases, two or more positive electrode active materials may be used in combination. Preferably, a lithium-transition metal composite oxide is used as the positive electrode active material from the viewpoint of capacity and output characteristics. Note that positive electrode active materials other than those described above may be used.

The negative electrode active material layer 7 includes a negative electrode active material. Examples of the negative electrode active material include natural graphite, MCMB (mesophase carbon microbead) type graphite, carbon materials such as graphite, soft carbon, and hard carbon, and lithium-transition metal composite oxide (for example, Li ₄ Ti ₅ O ₁₂ ). , Si, Ge, Sn, Pb, Al, In, Zn, and the like materials that form an alloy with lithium, lithium alloy negative electrode materials, and the like. In some cases, two or more negative electrode active materials may be used in combination. Preferably, from the viewpoint of capacity and output characteristics, a carbon material, a lithium-transition metal composite oxide, or a material alloyed with lithium is used as the negative electrode active material. Note that a negative electrode active material may be used as long as it is water-insoluble other than the above.

  The average particle diameter of each active material contained in the positive and negative electrode active material layers 9 and 7 is not particularly limited and may be about 0.1 to 100 μm, but from the viewpoint of increasing the output, preferably 1 to 20 μm. It is.

  The positive electrode active material layer 9 and the negative electrode active material layer 7 contain a binder. In the method for reusing a negative electrode active material according to this embodiment, a material containing a non-aqueous binder in the negative electrode active material layer 7 is used.

  The binder used for the positive electrode active material layer 9 is not particularly limited, for example, either an organic solvent-based binder (non-aqueous binder) or a water-dispersed binder (aqueous binder) can be used. For example, the following materials are mentioned. Polyethylene, polypropylene, polyethylene terephthalate, polyether nitrile, polyacrylonitrile, polyimide, polyamide, cellulose, carboxymethyl cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, styrene-butadiene rubber, isoprene rubber, butadiene rubber, ethylene Thermoplastic polymers such as propylene rubber, ethylene / propylene / diene copolymers, styrene / butadiene / styrene block copolymers and their hydrogenated products, styrene / isoprene / styrene block copolymers and their hydrogenated products, polyfluorinated Vinylidene (PVDF), polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether Copolymers, ethylene / tetrafluoroethylene copolymers, polychlorotrifluoroethylene, ethylene / chlorotrifluoroethylene copolymers, fluororesins such as polyvinyl fluoride, vinylidene fluoride-hexafluoropropylene fluororubber, vinylidene fluoride Ride-hexafluoropropylene-tetrafluoroethylene-based fluororubber, vinylidene fluoride-based fluororubber, epoxy resin and the like. Among these, polyvinylidene fluoride, polyimide, styrene / butadiene rubber, carboxymethyl cellulose, polypropylene, polytetrafluoroethylene, polyacrylonitrile, and polyamide are more preferable. These suitable binders are excellent in heat resistance, have a very wide potential window and are stable, and can be used for the active material layer. These binders may be used alone or in combination of two.

  The amount of the binder contained in the positive electrode active material layer 9 is not particularly limited as long as it is an amount capable of binding the active material, but is preferably 0.5 to 15 mass with respect to the active material layer. %, More preferably 1 to 10% by mass.

  The binder used for the negative electrode active material layer 7 may be a non-aqueous binder (organic solvent binder). Examples of the non-aqueous binder (organic solvent binder) include fluorine-containing binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), polyimide, polytetrafluoroethylene, polyethylene, polypropylene, polyetherimide, Polyimide resins such as polyamideimide (PAI), polyamide resins such as PA66, polyether ether ketone (PEEK), polyarylate (PAR), polyether sulfone (PES), polyphenylene sulfide (PPS), polyphenylene ether (PPE), polyethylene Examples include terephthalate (PET) and polybutylene terephthalate (PBT). These may be used alone or in combination of two or more.

  In the negative electrode active material layer 7 containing these non-aqueous binders (organic solvent binders), the negative electrode active material layer 7 and the negative electrode current collector 5 can be peeled off using an aqueous solution having a temperature higher than 50 ° C. That is, the non-aqueous binder is bound to the surface of the negative electrode current collector 5 at the interface between the negative electrode active material layer 7 and the negative electrode current collector 5, but the negative electrode current collector is immersed in an aqueous solution having a temperature higher than 50 ° C. The bonding strength of the non-aqueous binder that is bound to the surface of the electric body 5 is reduced and can be peeled off. Conventionally, it was considered that the functional group on the surface of the negative electrode current collector 5 and the non-aqueous binder have high adhesion and are difficult to peel off (for example, a strong chemical bond by a chemical reaction). Therefore, techniques such as dissolving the current collector using a strong acid have been taken. On the other hand, the present inventors diligently immerse themselves in water heated to a predetermined temperature range without dissolving the negative electrode current collector 5 using a strong acid without being caught by conventional technical common sense. Thus, it has been found that the adhesion of the non-aqueous binder can be reduced, and the negative electrode active material layer containing the non-aqueous binder can be easily peeled off from the current collector in the form of a film. It is considered that peeling of the negative electrode material (negative electrode active material layer) with water is caused by the following action. That is, the negative electrode active material layer is a layer having voids. The adhesion portion with the current collector is formed of a non-aqueous (organic solvent) binder, but is formed of a point and line contact aggregate. At room temperature (and the electrolyte heated at the time of charging / discharging), the current collector and the active material do not peel off, but the non-aqueous binder such as PVDF softens as the temperature rises, and the non-aqueous binder such as PVDF Adhesive strength also decreases. In addition, the surface tension of water decreases as the temperature rises, making it easy for water to enter the adhesive interface and leading to peeling. This tendency increases as the temperature rises, and the time until peeling becomes shorter. At 100 ° C., the water that has entered the interface becomes steam, so that the force to lift and peel off the negative electrode active material layer increases, and can be peeled off in about 10 minutes. In addition, when the stirring is performed, the peeling time is shortened. This is considered because the water hits the interface (cross section) between the negative electrode active material layer and the current collector to cause a physical peeling force. The non-aqueous binder that binds the active material particles to each other may be immersed in an aqueous solution at a temperature higher than 50 ° C. due to a strong bond (physical bond) due to the anchor effect due to the unevenness of the active material particle surface. Since the bond can be maintained, it can be easily recovered in the film state. In addition, since an aqueous solution can be used instead of an acid or an alkali, the composition of the negative electrode active material layer can be recovered with almost no change. For this reason, after drying the negative electrode active material layer, it can be made into a slurry by adding a viscosity adjusting solvent (for example, NMP), stirring with a homogenizer, etc., and mixing and mixing, and can be applied to the negative electrode current collector. . Thereby, it can reuse as a negative electrode. In addition, since no strong acid or strong alkali is used and no solid waste is generated, an environmentally friendly and inexpensive rechargeable battery can be supplied.

  The amount of the non-aqueous binder contained in the negative electrode active material layer 7 is not particularly limited as long as it is an amount capable of binding the active material, but is preferably 0.5 to It is 15 mass%, More preferably, it is 1-10 mass%.

  Examples of other additives that can be included in the positive and negative electrode active material layers 9 and 7 include a conductive additive, an electrolyte salt (lithium salt), and an ion conductive polymer.

  The conductive assistant refers to an additive that is blended in order to improve the conductivity of the positive electrode active material layer 9 and the negative electrode active material layer 7. Examples of the conductive assistant include carbon materials such as carbon black such as acetylene black, graphite, and vapor grown carbon fiber. When the active material layer contains a conductive additive, an electronic network inside the active material layer is effectively formed, which can contribute to improvement of the output characteristics of the battery.

Examples of the electrolyte salt (lithium salt) include Li (C ₂ F ₅ SO ₂ ) ₂ N, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , and LiBETI.

  Examples of the ion conductive polymer include polyethylene oxide (PEO) -based and polypropylene oxide (PPO) -based polymers.

  The compounding ratio of the components contained in the positive electrode active material layer and the negative electrode active material layer is not particularly limited. The blending ratio can be adjusted by appropriately referring to known knowledge about lithium ion batteries. The thickness of each active material layer is not particularly limited, and conventionally known knowledge about the battery can be appropriately referred to. For example, the thickness of each active material layer is about 2 to 100 μm.

(C) Electrolyte layer (electrolyte impregnated separator)
As the electrolyte constituting the electrolyte layer 11, an electrolytic solution (liquid electrolyte) or a polymer electrolyte is used.

  The liquid electrolyte has a form in which a lithium salt as a supporting salt is dissolved in an organic solvent as a plasticizer. Examples of the organic solvent that can be used as the plasticizer include carbonates such as ethylene carbonate (EC), propylene carbonate, and diethyl carbonate (DEC). Further, as the supporting salt (lithium salt), a compound that can be added to the active material layer of the electrode, such as LiBETI, can be similarly employed.

  On the other hand, the polymer electrolyte is classified into a gel electrolyte containing an electrolytic solution and an intrinsic polymer electrolyte containing no electrolytic solution.

  The gel electrolyte has a configuration in which the liquid electrolyte (electrolytic solution) is injected into a matrix polymer made of an ion conductive polymer. Examples of the ion conductive polymer used as the matrix polymer include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. In such polyalkylene oxide polymers, electrolyte salts such as lithium salts can be well dissolved.

  The ratio of the liquid electrolyte (electrolytic solution) in the gel electrolyte is not particularly limited, but is preferably about several mass% to 98 mass% from the viewpoint of ionic conductivity. In the present embodiment, the gel electrolyte having a large amount of electrolytic solution having a ratio of the electrolytic solution of 70% by mass or more is particularly effective.

  When the electrolyte layer 11 is composed of a liquid electrolyte, a gel electrolyte, or an intrinsic polymer electrolyte, the separator 10 may be used for the electrolyte layer 11. Specific examples of the separator 10 constituting the electrolyte layer 11 include a microporous film made of polyolefin such as polyethylene or polypropylene. Moreover, a nonwoven fabric separator etc. can also be used. Furthermore, a separator provided with a heat-resistant layer made of an organic resin or inorganic particles on the surface can also be used.

  The intrinsic polymer electrolyte has a structure in which a supporting salt (lithium salt) is dissolved in the matrix polymer, and does not include an organic solvent that is a plasticizer. Therefore, when the electrolyte layer is composed of an intrinsic polymer electrolyte, there is no fear of liquid leakage from the battery, and the reliability of the battery can be improved.

  The matrix polymer of the gel electrolyte or the intrinsic polymer electrolyte can exhibit excellent mechanical strength by forming a crosslinked structure. In order to form a crosslinked structure, thermal polymerization, ultraviolet polymerization, radiation polymerization, electron beam polymerization, etc. are performed on a polymerizable polymer (for example, PEO or PPO) for forming a polymer electrolyte using an appropriate polymerization initiator. A polymerization treatment may be performed.

(D) Electrode tabs and leads The electrode tabs 3 and 4 may be used for the purpose of taking out current outside the battery. The electrode tab is electrically connected to a current collector or a current collector plate, and is taken out of the laminate sheet which is a battery exterior material.

  The material which comprises an electrode tab is not restrict | limited in particular, The well-known highly electroconductive material conventionally used as an electrode tab for LIB may be used. As a constituent material of the electrode tab, for example, metal materials such as aluminum, copper, titanium, nickel, stainless steel, and alloys thereof are preferable, and aluminum, copper, and the like are more preferable from the viewpoint of light weight, corrosion resistance, and high conductivity. . The positive electrode tab 4 and the negative electrode tab 3 may be made of the same material or different materials.

  A positive terminal lead and a negative terminal lead (both not shown) are also used as necessary. As the material of the positive terminal lead and the negative terminal lead, a terminal lead used in a known LIB can be used. It should be noted that the part taken out from the battery outer packaging material 14 has a heat insulation property so as not to affect a product (for example, an automobile part, particularly an electronic device, etc.) by contacting with a peripheral device or wiring and causing a leakage. It is preferable to coat with a heat shrinkable tube or the like.

(E) Battery exterior material As the battery exterior material 14, a well-known metal can case can be used, and a bag-like case using a laminate film containing aluminum that can cover the power generation element is used. For example, a laminate film having a three-layer structure in which PP, aluminum, and nylon are laminated in this order can be used as the laminate film, but the laminate film is not limited thereto. A laminate film is desirable from the viewpoint that it is excellent in high output and cooling performance, and can be suitably used for a battery for large equipment for EV and HEV.

(2) Appearance of Battery FIG. 2 schematically shows the appearance of a laminated flat lithium ion battery that can be recycled as a used LIB that can be applied to any of the following embodiments. It is a perspective view. As shown in FIG. 2, the recyclable stacked battery 1 has a rectangular flat shape, and negative electrode tabs 3 and positive electrode tabs 4 for taking out electric power from both sides thereof. Has been pulled out. The power generation element 2 is wrapped by a battery outer body 14 and its periphery is heat-sealed. The power generation element 2 is sealed with the negative electrode tab 3 and the positive electrode tab 4 pulled out. Here, the power generation element 2 corresponds to the power generation element 2 of the stacked battery 1 shown in FIG. 1, and a plurality of unit cell layers 13 including the negative electrode active material layer 7, the electrolyte layer 11, and the positive electrode active material layer 9 are stacked. It has been done.

  The reusable LIB is not limited to a flat shape (stacked type) as shown in FIGS. For example, the wound type LIB may have a cylindrical shape, or may be a flattened rectangular shape by deforming such a cylindrical shape. In the cylindrical shape, a laminate sheet or a conventional cylindrical can (metal can) may be used as the exterior material, and there is no particular limitation. Preferably, the power generation element is covered with an aluminum laminate film. With this configuration, it is easy to reduce the weight and apply the method for reusing a negative electrode active material of the present embodiment.

  Further, the extraction of the electrode tabs 3 and 4 shown in FIG. 2 is not particularly limited, and the negative electrode tab 3 and the positive electrode tab 4 may be pulled out from the same side, or a plurality of the negative electrode tab 3 and the positive electrode tab 4 may be provided. You may make it take out from each edge. Further, in a wound LIB, instead of the electrode tab, for example, a terminal may be formed using a cylindrical can (metal can).

  The reusable LIB can be a used battery suitably used for a vehicle driving power source or an auxiliary power source of an electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a hybrid fuel cell vehicle, or the like.

  Hereinafter, typical embodiments will be described in detail.

  In this embodiment, (1) a step of immersing a negative electrode having a negative electrode active material layer containing a non-aqueous binder and a current collector in an aqueous solution having a temperature higher than 50 ° C. 2) a step of recovering the peeled negative electrode active material layer; and (3) a step of applying (applying) the recovered negative electrode active material layer to a current collector again (after drying and slurrying). Reuse method of negative electrode active material layer (negative electrode). In this recycling method, the effects of the present invention described above can be achieved, and the battery capacity can be recovered to 70% or more (see Examples 1 to 12).

  In the method for reusing a negative electrode of the present embodiment, an unused negative electrode such as an end material coated with a negative electrode material produced during production of the negative electrode, an improper assembly produced in the assembly process, or the like Used LIB negative electrodes (hereinafter, simply referred to as negative electrodes) are targeted.

  If usable capacity remains in the used LIB, there is a risk of self-discharge during the regeneration. Therefore, the electrode tabs 3 and 4 (FIG. 1) are used until no usable remaining capacity remains. 2), it is necessary to discharge sufficiently to make it harmless. Specifically, it is desirable that the discharged LIB is sufficiently discharged by 1C discharge until the discharge voltage of the used LIB becomes 2.5 V (or less). In other words, detoxification as used herein refers to reduction to 2.5 V (or less) per unit cell by 1 C discharge. Moreover, when there is no remaining capacity that can be used, the above steps (1) to (3) may be performed without performing the above-described discharge treatment (detoxification treatment).

  In addition, LIB has a characteristic that the usable discharge capacity gradually decreases as charging and discharging are repeated (the use period becomes longer). Therefore, it is difficult to uniquely define whether or not the LIB is a used LIB because it varies depending on the intended use and the user. In the present embodiment, it is assumed that the discharge capacity that can be used after charging (full charge) to at least the specified voltage is less than half of the new initial discharge capacity, but the user also feels inconvenience. Thus, all LIBs determined to be used (discarded) can be targeted.

Step (1) In this recycling method, as the step (1), a step of immersing a negative electrode having a negative electrode active material layer containing a non-aqueous binder and a current collector in an aqueous solution having a temperature higher than 50 ° C. Do.

  Here, when the used negative electrode of LIB is used, a pretreatment process as shown in Example 12 may be performed.

(Pretreatment process)
For the used LIB, if necessary, the used LIB is discharged to make it harmless. Thereafter, the outer periphery of the laminate exterior material 14 is cut so as not to damage the positive and negative electrodes in the glove box, and the negative electrode is collected. Thereafter, the negative electrode is immersed in a beaker filled with a polar solvent (for example, ethyl alcohol) for a predetermined time (for example, 30 minutes) to dissolve the electrolytic solution and the deposit, and then again a fresh polar solvent (for example, for example, Rinse with ethyl alcohol for a predetermined time (for example, about 1 minute). Thereafter, the rinsed negative electrode may be dried at a predetermined temperature (for example, 80 ° C.).

This pretreatment process (a)
Specifically, first, the used LIB is sufficiently discharged and rendered harmless as necessary, and then the pretreatment step (a) of treating the used battery negative electrode (simply called used negative electrode) with a polar solvent (a )I do.

  Specifically, each used negative electrode is composed of a current collector and a negative electrode active material layer formed on the current collector. The negative electrode active material layer is formed of a plurality of negative electrode active material particles whose surfaces are covered with a deposit (SEI) and a binder (and further a conductive aid as necessary).

  In this pretreatment step (a), the used negative electrode is treated with a polar solvent to form a solvent-treated electrode. Specifically, the used negative electrode is dissolved with a polar solvent to dissolve deposits adhering to the surface of the active material particles of the electrolytic solution and the negative electrode, and then rinsed (washed) again with a fresh polar solvent. By treating with the polar solvent in this way, the deposits are peeled off from the surface of each active material particle in the used negative electrode first immersed in the polar solvent for a predetermined time (for example, 30 to 60 minutes), and the electrolytic solution is dissolved in the polar solvent. And the sediment is dissolved. The polar solvent in which the electrolytic solution and the deposit are dissolved may be removed from the system, but it is desirable that these are recovered and reused. After that, by rinsing the negative electrode again with a fresh polar solvent, the electrolyte and deposits that remain slightly together with the polar solvent are almost completely washed away (washed off), and are removed from the negative electrode to be treated with a solvent. It can be an electrode.

  Here, deposits attached to the surface of the active material particles of the electrode electrode, specifically, deteriorated substances containing Li, such as deposited Li organic salts, which are the main components of capacity deterioration, are simply referred to as SEI (solid electrolyte). Also referred to as interface). This SEI is said to be made by: That is, during repeated use of LIB charge / discharge, Li ions are repeatedly inserted and desorbed (or alloyed / dealloyed) between the electrode (positive electrode / negative electrode) active material and the electrolytic solution. At that time, the electrolytic solution (organic solvent + lithium salt) is partially reduced and decomposed. The organic compound derived from the solvent such as a decomposition product of the reductively decomposed organic solvent, or a composite such as Li and positive electrode-derived ions forms a film in which Li ions pass but no electrons pass through the surface of the active material particles of the negative electrode. That's it. In this embodiment, since this SEI specifically dissolves in a polar solvent having a dielectric constant of 5.0 or more, the used electrode is pulverized by utilizing the excellent cleaning effect of the polar solvent. In addition, a high capacity recovery rate can be achieved when it is reused. In addition to so-called SEI, there is a possibility that deposits of salts such as LiF may be generated depending on the cell constituent components. However, since these salts are also washed with a polar solvent, the effect is the same. Hereinafter, in the present embodiment, the deposit is described as being representative of SEI.

  In the pretreatment step (a), it is desirable to perform ultrasonic treatment when treating with a polar solvent. This is because when the used negative electrode is soaked in a polar solvent and treated, the inside of the negative electrode active material layer can be well washed with ultrasonic waves by performing ultrasonic treatment. That is, the cleaning solvent (polar solvent) can permeate the negative electrode active material layer evenly and can be cleaned. Therefore, even the electrolyte solution inside the negative electrode active material layer and the SEI on the surface of the negative electrode (active material particles) can be uniformly dissolved and removed effectively in a polar solvent. Cleaning by ultrasonic treatment is desirably 10 minutes or more and 60 minutes or less. If the cleaning time by ultrasonic treatment is 10 minutes or more, it is excellent in that it can be permeated evenly and the inside of the negative electrode active material layer can be washed well (electrolytic solution and deposits are removed). On the other hand, if the cleaning time by the ultrasonic treatment is within 60 minutes, the heat is not increased excessively by the ultrasonic wave, and the negative electrode active material layer is not damaged, and the active material layer is not peeled off by vibration, effectively. It is excellent in that the inside of the negative electrode active material layer can be washed well (electrolytic solution and deposits are removed). The ultrasonic wave (frequency) may be appropriately adjusted according to the degree of contamination of the negative electrode (particularly, the degree of SEI adhesion on the surface of the negative electrode (active material particles)). Usually, it is sufficient to use a frequency in the vicinity of 40 KHz. However, for stubborn dirt, it is effective to lower the frequency and remove it with the force of cavitation, and it is preferable to use a frequency in the vicinity of 28 kHz. Further, it is effective to remove the delicate dirt by increasing the frequency and reducing the cleaning unevenness, and it is preferable to use a frequency of 100 kHz or more. It is desirable to appropriately determine the optimum ultrasonic wave (frequency), for example, by conducting a preliminary experiment in advance. Here, the used negative electrode refers to a negative electrode of a used stacked battery. Further, the “polar solvent” in the present embodiment refers to a solvent having a dielectric constant of 5.0 or more.

  Although it does not restrict | limit especially as said polar solvent, For example, water, methanol, ethanol, n-propanol, isopropanol, 1-butanol, 2-butanol, formic acid, acetic acid, propionic acid, ethylene glycol, propylene glycol, etc. Protic polar solvents; aprotic polar solvents such as diethyl ether, ethyl acetate, tetrahydrofuran, pyridine, dimethyl sulfoxide, acetonitrile, cyclohexanone, acetone, methyl ethyl ketone, 1,4-dioxane, 1,3-dioxolane, ethylene glycol dimethyl ether A polar solvent or the like can be used. However, it is not limited to these polar solvents. Moreover, the polar solvent illustrated above may be used individually by 1 type, and may use 2 or more types together. Among these, it is desirable to use a protic polar solvent.

About pre-processing process (b) Next, the process of drying the said solvent processing electrode is performed as pre-processing process (b).

  The drying may be performed under the same conditions as (i) drying the current collector coated with the electrode slurry in the electrode manufacturing process when the battery is manufactured, but is not limited to such a method. is not. For example, the solvent-treated electrode can be dried under appropriate drying conditions to form a dry electrode. As the drying condition of (i) above, drying may be performed at 60 to 150 ° C. for 5 to 24 hours at 0.1 atm or less in a vacuum dryer. However, it is not limited at all to the drying conditions of (i) above, and even if it is outside the range of the drying conditions, there is no limitation as long as it does not impair the effects of the present embodiment. . When returning the pressure reduction, it is desirable to use dry air or argon gas in a dry box. Alternatively, (ii) the solvent-treated electrode can be dried in a dry box using dry air (dry air) or Ar gas under suitable drying conditions to obtain a dry electrode. The drying condition (ii) may be performed at 60 to 150 ° C. for 3 to 24 hours under atmospheric pressure. However, it is not limited at all to the drying condition of (ii), and even if it is outside the range of the drying condition, it is not limited at all as long as it does not impair the effects of this embodiment. . If the pressure in the vacuum dryer at the time of drying (i) is 0.1 atm or less, the pressure can be sufficiently reduced (vacuum), so that the vaporized solvent can be removed under reduced pressure without liquefaction again. It is excellent in that the inside can be sufficiently dried in a short time. Even when dry air or Ar gas is used in the dry box during the drying of (ii) above, the vaporized solvent can be removed outside the dry box without being liquefied again, and the inside of the negative electrode can be sufficiently removed in a short time. It is excellent in that it can be dried. If the drying temperature of said (i) and (ii) is 60 degreeC or more, an organic solvent can be evaporated quickly and it can fully dry to a negative electrode inside for a short time. A drying temperature of 150 ° C. or lower is excellent in that the drying rate can be increased without causing deterioration of the negative electrode active material or the like. Moreover, if the drying time of said (i) (ii) is 3 hours or more, it can fully dry to the inside of an electrode, without leaving an organic solvent. When the drying time is 24 hours or less, the inside of the negative electrode can be sufficiently dried, and the drying cost is excellent. However, in the present embodiment, the drying method is not limited at all. Drying by vacuum heating using the vacuum dryer described above does not leave a polar solvent inside the solvent-treated electrode, it can be uniformly heated to the inside of the negative electrode active material layer, and drying more uniformly Excellent in that it can be done.

  Next, in this step (1), for example, a negative electrode peeling apparatus as shown in FIGS. 3 to 5 can be used.

  Here, the negative electrode stripping device 31 of FIG. 3 has a configuration in which an appropriate amount of the aqueous solution 16 as a stripping solution is placed in the stripping tank 15 and provided on a heating device (such as a heater) 17.

  Further, the negative electrode peeling device 32 in FIG. 4 has an appropriate amount of the aqueous solution 16 as a peeling solution in the peeling tank 15, and the configuration provided on the heating device (heater or the like) 17 is the same as the negative electrode peeling device 31 in FIG. 3. It is. The negative electrode stripping device 32 is further provided with a stirring device in which a propeller (stirring blade) 18 immersed in the aqueous solution 16 is connected to a stirring motor 19 above the stripping tank 15. A stainless steel net 20 is attached at a position higher than the propeller (stirring blade) 18 in the peeling tank 15 so that the negative electrode does not contact. That is, the propeller can be stirred, and the negative electrode 8 is partitioned by a stainless steel mesh 20 so that the negative electrode 8 does not hit the propeller (stirring blade) 18, and the negative electrode 8 is inserted (immersed) above the stainless steel mesh 10. It is. In the negative electrode peeling device 32 of FIG. 4, a propeller stirring device is used as the stirring device (means), but the stirring is not limited to the propeller, but by air blowing or by a magnetic stirrer stirrer Of course, any device capable of stirring can be used. Moreover, the thing by the stirring bar by a magnetic stirrer etc. can fully be applied also to the negative electrode peeling apparatus 33 of FIG.

  Furthermore, the negative electrode peeling apparatus 33 of FIG. 5 includes a stainless steel pressure vessel 21 and a stainless steel pressure vessel lid 22, and an appropriate amount of the aqueous solution 16 as a peeling solution is placed in the pressure vessel 21, and a heating device (such as a heater). ) The structure provided on 17 is the same as that of the negative electrode peeling apparatus 31 of FIG. In the negative electrode peeling device 33, the stainless pressure vessel 22 is further provided with a pressure regulating valve 23 for adjusting the pressure in the pressure vessel 21. Further, the flange portion (the pressure vessel 21 side or the pressure vessel lid) of the peripheral joint portion between the pressure vessel 21 and the pressure vessel lid 22 so that the inside of the pressure vessel can be sealed when the stainless pressure vessel lid 22 is closed. 22 side) is provided with a seal member 24. The negative electrode peeling apparatus 33 of FIG. 5 is suitable when immersed in an aqueous solution having a temperature exceeding 100 ° C.

  As the heating device (heater or the like) 17 of the negative electrode stripping devices 31 to 33 described above, a device in which the temperature (liquid temperature or water temperature) of the stripping solution (aqueous solution) 16 can be controlled to a set temperature (see Examples) is used. That's fine. That is, the temperature may be set so that the temperature (liquid temperature or water temperature) of the stripping solution (aqueous solution) 16 falls within a predetermined temperature range (temperature higher than 50 ° C.) when the negative electrode is immersed. In addition, the negative electrode may be preheated to about 50 ° C. using warm air or the like before immersion so that the water temperature of the aqueous solution 16 does not change suddenly before and after the immersion of the negative electrode.

  In this step (1), the negative electrode 8 having a negative electrode active material layer containing a non-aqueous binder and a current collector is heated to a temperature higher than 50 ° C. by the heating device (heater or the like) 17 of the negative electrode peeling devices 31 to 33 described above. It is immersed in a stripping solution (aqueous solution) 16 that has been heated.

  The immersion temperature when the negative electrode is immersed (the temperature of the stripping solution (aqueous solution) 16) is higher than 50 ° C., preferably 60 ° C. or higher. This can be peeled off at an immersion temperature of 50 ° C., but can be peeled off at 60 ° C. or higher, and can suppress deterioration of the constituent members of the negative electrode active material layer. As a result, a high capacity recovery rate (see Table 1) can be exhibited in the rechargeable battery using the negative electrode obtained by reusing the peeled negative electrode active material layer.

  Since the immersion time when the negative electrode is immersed varies depending on the immersion temperature (water temperature of the aqueous solution 16), it is not particularly limited, and the negative electrode active material layer 7 constituting the negative electrode 8 has the current collector 5 (+ What is necessary is just to immerse until it peels from the negative electrode tab 3) (refer Examples 1-12). In consideration of the experimental results of the examples, the immersion time may be appropriately selected in the range of 0.05 to 10 hours, preferably in the range of 0.1 to 6 hours, depending on the immersion temperature. 3 and 5 are not provided with the stirring device as shown in FIG. 4, but the convection of the aqueous solution 16 in the peeling tank 15 or the pressure vessel 21 is caused by heating by a heating device (such as a heater). Can be awakened. Due to this convection phenomenon, the negative electrode active material layer 7 constituting the negative electrode 8 can be peeled off from the current collector 5 (+ the negative electrode tab 3) without particularly providing a stirring device. Preferably, it is desirable to include a step of stirring in this step (1) using the negative electrode peeling device 32 provided with a stirring device as shown in FIG. It is because peeling time can be shortened by stirring (refer an Example).

  The aqueous solution 16 used in this step (1) is preferably water. Specifically, pure water, ion exchange water, tap water (tap water), well water (ground water), rain water (reserved water), industrial water, sea water From the above, desalted water, sewage-treated water and the like can be used. In addition, water is a water-soluble solvent (for example, methanol, ethanol, n-propanol, isopropanol, etc.) or various additives (for example, an interface) that volatilizes by drying as long as it does not interfere with the effects of the present invention. An appropriate amount of an activator or the like may be mixed.

  In the reuse method, the negative electrode active material layer containing a non-aqueous binder is used in the negative electrode active material layer containing an aqueous dispersion binder (aqueous binder) such as SBR, as shown in the examples. This is because the negative electrode active material layer cannot be peeled from the current collector by (1). On the other hand, it has been found that in a negative electrode active material layer containing an organic solvent binder (non-aqueous binder) such as PVDF, the negative electrode active material layer can be peeled off from the current collector by the step (1). Furthermore, the negative electrode active material layer peeled and recovered in step (3) can be slurried with a normal viscosity adjusting solvent (for example, NMP) and applied to a current collector to form a negative electrode active material layer. By doing so, it has been found that it can be reused as a negative electrode. As for the non-aqueous binder, those described in the column of the non-aqueous binder used for the negative electrode active material layer 7 in the column of (1) (b) active material layer in the description of the constituent requirements of the battery can be given.

Step (2) In this recycling method, as the step (2), a step of collecting the peeled negative electrode active material layer is performed.

In step (2), for example, (a) after collecting the negative electrode current collector (+ negative electrode tab) from the peeling tank 15 or the pressure vessel 21 using a magnet or the like, the residue in the peeling tank 15 or the pressure vessel 21 ( The negative electrode active material layer can be recovered by filtering the aqueous solution 16 + the negative electrode active material layer. Alternatively, (b) the negative electrode active material layer may be scraped and collected from the residue (aqueous solution 16 + negative electrode active material layer) using a net or the like. In this case, by reusing the heated aqueous solution 16 in the above step (1), the amount of energy used to heat the aqueous solution can be reduced, contributing to the reduction of CO ₂ emissions, and economical. But it ’s good in some ways. Or (c) The contents of the peeling tank 15 and the pressure vessel 21 (aqueous solution 16 + peeled negative electrode active material layer + negative electrode current collector (+ negative electrode tab)) are filtered to remove the peeled negative electrode active material layer + negative electrode current collector. Collect body (+ negative electrode tab). Thereafter, the negative electrode current collector (+ negative electrode tab) is recovered from the filtrated material (peeled negative electrode active material layer + negative electrode current collector (+ negative electrode tab)) using a magnet or the like. There is no particular limitation such as isolation and recovery.

  The collected negative electrode active material layer may be dried by an appropriate method. Here, the recovered negative electrode active material layer may be dried within a range in which the constituent components of the negative electrode active material layer do not deteriorate. The drying method is not particularly limited, such as natural drying, hot air drying, and vacuum drying. For example, in the case of vacuum drying, as drying conditions, drying may be performed at 60 to 150 ° C. for about 0.5 to 5 hours at 0.1 atm or less in a vacuum dryer. However, the drying conditions are not limited at all, and are not limited as long as the operational effects of the present embodiment are not impaired even if they are outside the range of the drying conditions. When returning to a reduced pressure, it is desirable to use dry air or Ar gas in a dry box. In the case of hot air drying, as drying conditions, drying may be performed at 60 to 150 ° C. for about 0.5 to 5 hours under atmospheric pressure in a hot air dryer. However, the drying conditions are not limited at all, and are not limited as long as the operational effects of the present embodiment are not impaired even if they are outside the range of the drying conditions. If the pressure in the vacuum dryer at the time of vacuum drying is 0.1 atm or less, it is excellent in that the inside of the negative electrode active material layer can be sufficiently dried in a short time. Even when dry air or Ar gas is used in a dry box during hot air drying, the inside of the negative electrode active material layer can be sufficiently dried in a short time. If the drying temperature of hot air drying or vacuum drying is 60 ° C. or higher, preferably 100 ° C. or higher, the aqueous solution can be quickly evaporated, and the inside of the negative electrode active material layer can be sufficiently dried in a short time. A drying temperature of 150 ° C. or lower, preferably 120 ° C. or lower, is excellent in that the drying rate can be increased without causing deterioration of the negative electrode active material or the like. Moreover, if the drying time of the said hot air drying or vacuum drying is 0.5 hour or more, it can fully dry to the negative electrode active material layer inside, without leaving aqueous solution. When the drying time is 5 hours or less, the inside of the negative electrode active material layer can be sufficiently dried, which is excellent in that the drying cost can be suppressed. However, in the present embodiment, the drying method is not limited at all. Drying by vacuum heating using the above-described vacuum dryer can uniformly bring the inside of the negative electrode active material layer into a vacuum heated state without any aqueous solution remaining inside the negative electrode active material layer. As a result, it is excellent in that it can be dried more uniformly. And if vacuum drying is used rather than hot air drying, the above-mentioned drying time can be shortened.

Step (3) In this reuse method, as the step (3), a step of attaching the recovered (dried) negative electrode active material layer to the current collector again is performed.

  In the step (3), for example, the recovered (dried) negative electrode active material layer is made into a slurry, and this slurry is applied to a current collector and dried to form (attach) the negative electrode active material layer again. It is a process. The negative electrode thus obtained can be reused as a negative electrode for a regenerative battery (LIB) (see Examples).

  Here, in order to make the recovered (dried) negative electrode active material layer into a slurry, for example, the dried negative electrode active material layer and the viscosity adjusting solvent are put into a stirring / mixing device (kneading device) and stirred at a predetermined temperature. , Mix.

  The stirring / mixing device (kneading device) is not particularly limited, and a device used to prepare a conventionally known electrode slurry can be used. Specifically, a homogenizer or the like as used in the examples can be used, but the apparatus is not limited to this.

  As the viscosity adjusting solvent, a viscosity adjusting solvent (for example, N-methyl-2-pyrrolidone (NMP)) used for forming a negative electrode slurry for producing LIB can be used. Further, the amount used thereof may be appropriately adjusted so that the negative electrode slurry used in the production of LIB has the same viscosity.

  The predetermined temperature is a temperature that is suitable for dissolving the non-aqueous binder in the dried negative electrode active material layer in the viscosity adjusting solvent, and is a temperature that does not deteriorate the components of the negative electrode active material layer. Good. Specifically, a range of 60 to 120 ° C. is desirable, but even if outside the above temperature range, there is no limitation as long as it does not impair the effects of the present embodiment.

  In addition, the method of applying the obtained slurry to a current collector and drying to form a negative electrode active material layer is not particularly limited, and the negative electrode slurry is applied to the current collector when LIB is produced. A method of forming a negative electrode active material layer by drying can be applied (see Examples).

  As the current collector, a new current collector may be used, or the current collected in step (1) may be reused if the state after collection is good.

  In addition, in order to apply the obtained slurry to the current collector, a conventionally known application method can be applied. For example, as shown in the examples, it can be applied using a die coat or the like. The application method is not limited at all.

  As a method of drying the obtained slurry after applying it to the current collector, a conventionally known drying method can be applied, and vacuum drying or hot air drying can be used. As vacuum drying conditions, drying may be performed at 110 to 150 ° C. for 5 to 24 hours at 0.1 atm or less in a vacuum dryer. However, it is not limited at all to the above vacuum drying conditions, and even if it is outside the range of the above drying conditions, it is not limited at all as long as it does not impair the effects of the present embodiment. When returning the pressure reduction, it is desirable to use dry air or argon gas in a dry box. Alternatively, dry air (dry air) or Ar gas may be used in a dry box to dry with hot air under suitable drying conditions. As hot air drying conditions, drying may be performed at 110 to 150 ° C. for 3 to 24 hours under atmospheric pressure. However, it is not limited to the hot air drying conditions, and even if it is outside the range of the drying conditions, there is no limitation as long as it does not impair the effects of the present embodiment. If the pressure in the vacuum dryer at the time of the vacuum drying is 0.1 atm or less, a sufficiently reduced pressure (vacuum) state can be obtained, so that the evaporated solvent can be removed under reduced pressure without liquefaction again, and the inside of the negative electrode can be shortened. It is excellent in that it can be sufficiently dried in time. Even when dry air or Ar gas is used in the dry box during hot air drying, the vaporized solvent can be removed outside the dry box without being liquefied again, and the inside of the negative electrode can be sufficiently dried in a short time. It is excellent in that it can. When the drying temperature is 110 ° C. or higher, the viscosity adjusting solvent can be quickly evaporated, and the inside of the negative electrode can be sufficiently dried in a short time. A drying temperature of 150 ° C. or lower is excellent in that the drying rate can be increased without causing deterioration of the negative electrode active material or the like. When the drying time is 3 hours or longer, the inside of the negative electrode can be sufficiently dried without leaving the viscosity adjusting solvent. When the drying time is 24 hours or less, the inside of the negative electrode can be sufficiently dried, and the drying cost is excellent. However, in the present embodiment, the drying method is not limited at all. Drying by vacuum heating using the vacuum dryer described above can be uniformly heated to the inside of the negative electrode active material layer without leaving the viscosity adjusting solvent, and can be dried more uniformly. Excellent in terms.

  In this step (3), a current collector in which a negative electrode active material layer is formed (negative electrode) is cut into a predetermined size and a negative electrode active material layer is not formed as shown in the examples. Up to the step of attaching the negative electrode tab to the end of the electric body and forming the negative electrode may be included. However, this step may be included in a part of the step of manufacturing a reusable battery using a current collector in which a negative electrode active material layer is formed (negative electrode).

  In the present embodiment, a reusable battery can be manufactured using the negative electrode obtained by the above-described method for reusing a negative electrode active material layer.

  The method for producing such a reusable battery is not particularly limited, and can be performed using a conventionally known method for producing a LIB battery. That is, the negative electrode obtained by the above-described method for reusing the negative electrode active material layer, the positive electrode obtained by the conventionally known LIB manufacturing method, and the conventionally known separator are laminated as shown in FIG. Assemble the power generation element. A reusable battery can be obtained by injecting an electrolytic solution into a battery in which the power generation element is housed in a battery exterior material (for example, a laminate film exterior material) in the same manner as a new battery. Specifically, a negative electrode obtained by the above-described method for reusing a negative electrode active material layer, a positive electrode obtained by an existing method, and a plurality of unused separators are assembled into a power generation element. A reusable battery can be obtained by storing this power generation element in an unused battery outer packaging material (laminate film outer packaging material) and injecting an electrolytic solution in the same manner as a new battery. Here, by injecting the liquid, the separator is impregnated with the electrolytic solution to form an electrolyte layer (it can be said that the power generation element is completed at this point).

  The effects of the present embodiment are as follows.

  According to this embodiment, the negative electrode active material layer containing a non-aqueous binder and the current collector can be separated (interface) using an aqueous solution. Therefore, the composition of the negative electrode active material layer can be recovered with almost no change. For this reason, after drying the negative electrode active material layer which peeled, it can be made into a slurry by adding a viscosity adjustment solvent (for example, N-methyl-2-pyrrolidone), and stirring and mixing by a homogenizer, and can apply | coat to a negative electrode collector. Thereby, it can reuse as a negative electrode which has a high capacity | capacitance recovery rate (refer an Example).

  As a result, no strong acid or strong alkali is used, and no solid waste is generated. Therefore, an environmentally friendly and inexpensive rechargeable battery can be supplied.

  The effects of the embodiment will be described using the following examples. However, the technical scope of the embodiment is not limited to the following examples.

[Example 1]
The positive electrode current collector 6 in FIG. 1 is an aluminum foil, the positive electrode active material is lithium manganate (LiMn ₂ O ₄ ), lithium nickelate (LiNi _0.8 Co _0.18 Al _0.05 O ₂ ), and the negative electrode current collector. A laminated lithium ion secondary battery 1 shown in FIGS. 1 and 2 using copper foil 5 and natural graphite as the negative electrode active material was prepared. Specifically, the laminate type lithium ion secondary battery shown in FIGS. 1 and 2 was produced as follows.

<Preparation of positive electrode>
The positive electrode current collector 6 is an aluminum foil (Al foil) having a size (area) of 32 mm × 42 mm and a thickness of 20 μm. The positive electrode active material is lithium manganate (LiMn ₂ O ₄ ) having an average particle diameter of 5 μm. Lithium nickelate (LiNi _0.8 Co _0.18 Al _0.05 O ₂ ) was used. PVDF was used as a binder, and carbon black and graphite were used as conductive aids. Preparation of the positive electrode 12 has an electrode composition ratio (mass ratio) of an active material (lithium manganate, lithium nickelate), a conductive assistant (carbon black, graphite), and a binder (PVDF) of 69: 23: 2. : 2: 4. First, an active material, a conductive additive, and a binder were weighed, an appropriate amount of NMP was added thereto, and the mixture was placed in a homogenizer container, and thoroughly stirred and mixed to prepare a slurry. Thereafter, using a die coater, a certain amount of this slurry is applied on one side of the positive electrode current collector 6 (Al foil; 200 mm × 290 mm) so that the positive electrode active material layer 9 has a size of 80 mm × 170 mm and dried. did. On the other side of the positive electrode current collector (Al foil) 6, a certain amount was applied so that the portion of the positive electrode active material layer 9 was 80 mm × 170 mm, dried, and pressed with a roll press. . It dried for 8 hours with the 130 degreeC vacuum dryer. Thus, the thickness (single side | surface) of the positive electrode active material layer 15 of the positive electrode 12 produced was 80 micrometers at the time of completion. The coated positive electrode current collector was cut out to have a size of 30 mm × 40 mm. An aluminum tab as a positive electrode tab (current collector plate) 4 is joined (electrically connected) to one end of the positive electrode current collector 6 where the positive electrode active material layer 9 is not formed by ultrasonic welding (positive connection). Positive electrode) 12 was obtained.

<Production of negative electrode>
As the negative electrode current collector, a copper foil having a size (area) of 32 mm × 45 mm and a thickness of 10 μm was used.

(Preparation of collection negative electrode)
The negative electrode is produced so that the electrode composition ratio (mass ratio) is such that the ratio of the active material (natural graphite), the conductive additive (carbon black), and the binder (PVDF) is 94.5: 0.5: 5. did. First, an active material, a conductive additive, and a binder were weighed, an appropriate amount of NMP was added thereto, and the mixture was placed in a homogenizer container, and thoroughly stirred and mixed to prepare a slurry. Thereafter, a predetermined amount of this slurry was applied to one side of a negative electrode current collector (Cu foil; 200 mm × 290 mm) using a die coater so that the negative electrode active material layer portion had a size of 80 mm × 170 mm and dried. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. A coating portion (80 mm × 170 mm) of this negative electrode was cut out. A large amount of this coated cut-out product was made and used as a recovery negative electrode (negative electrode). The coating amount (negative electrode active material layer weight) of the recovery negative electrode (negative electrode) was 51.82% by mass of the negative electrode weight.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode peeling apparatus 31 of FIG. 3 was used. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 100 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 0.2 hours, since the negative electrode active material layer portion was peeled off (step (1)), the negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2) )). The weight of the recovered product was 25.41 g. still. The negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 100 ° C. until 0.2 hours after peeling (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of reusable batteries>
As shown in FIG. 1, one positive electrode 12 and two negative electrodes 8 are alternately stacked between the positive electrode 12 and the negative electrode 18 manufactured as described above, with the separator 10 serving as the outermost electrode. Thus, a power generation element (laminate) 2 was obtained. The positive electrode tab 4 and the negative electrode tab 3 attached to the current collectors 5 and 6 of the power generation element 2 were inserted into an Al laminate film back as an exterior material 14 so as to have a structure for taking out to the outside. This was again dried with a vacuum dryer at 80 ° C. for 8 hours. Thereafter, an electrolytic solution is injected into the back 14 through an opening from the opening of the film back 14, and the opening is sealed (sealed) by heat-sealing under reduced pressure to form two unit cell layers ( A laminate type lithium ion secondary battery 1 composed of (single cell) 13 was produced.

As the separator 10, a polypropylene microporous film having a size (area) of 36 mm × 50 mm and a thickness of 25 μm was used. As the electrolytic solution, a mixed solution of EC and DEC (EC: DEC = 3: 7 volume ratio) containing 1M LiPF ₆ was used. Here, EC is ethylene carbonate, and DEC is diethyl carbonate. The electrolyte layer 11 was formed by impregnating the separator with the electrolytic solution by injecting the electrolytic solution.

<Production of new battery>
The positive electrode produced above was used as the positive electrode. As the negative electrode, a negative electrode made of a collecting negative electrode was used, and the negative electrode active material layer 7 portion was cut out to a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). Connected). As shown in FIG. 1, one positive electrode 12 and two negative electrodes 8 are alternately laminated between the positive electrode 12 and the negative electrode 8 manufactured as described above, with the separator 10 serving as the outermost side. Thus, a power generation element (laminate) 2 was obtained. The positive electrode tab 4 and the negative electrode tab 3 attached to the current collectors 5 and 6 of the power generation element 2 were inserted into an Al laminate film back as an exterior material 14 so as to have a structure for taking out to the outside. This was again dried with a vacuum dryer at 80 ° C. for 8 hours. Thereafter, an electrolytic solution is injected into the back 14 through an opening from the opening of the film back 14, and the opening is sealed (sealed) by heat-sealing under reduced pressure to form two unit cell layers ( A laminate type lithium ion secondary battery 1 composed of (single cell) 13 was produced. The separator 10 is a mixed solution of EC and DEC containing 1M LiPF ₆ using a polypropylene microporous membrane having a size (area) of 36 mm × 50 mm and a thickness of 25 μm (EC: DEC = 3: 7). Volume ratio) was used. Here, EC is ethylene carbonate, and DEC is diethyl carbonate. The electrolyte layer 11 was formed by impregnating the separator with the electrolytic solution by injecting the electrolytic solution.

<Battery capacity>
(New battery capacity)
The initial capacity of the new laminate-type lithium ion secondary battery 1 produced as described above was 45.78 mAh. When this battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 34.36 mAh. The capacity retention rate was 75.05%.

(Recycled battery capacity)
The initial capacity of the negative electrode reuse laminate-type lithium ion secondary battery 1 produced above was 42.42 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.50 mAh. The capacity retention rate was 71.9%. The capacity recovery rate compared with the new capacity after deterioration was 88.77% (= 30.50 mAh ÷ 34.36 mAh × 100).

  Of the 300 charge / discharge conditions including the initial charge / discharge, the charge condition is 45 ° C. and constant current / constant voltage method (CCCV, current: 1 C, cell voltage: 4.2 V) for a total of 2.5 hours. The charging process was performed. The discharge conditions were 45 ° C. and a constant current method (CC, current: 1 C).

[Example 2]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling apparatus 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 90 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 2 hours, since the negative electrode active material layer portion was peeled off (step (1)), the negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2)). . The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 90 ° C. until 2 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reuse laminate type lithium ion secondary battery 1 produced above was 42.55 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.71 mAh. The capacity retention rate was 72.17%. The capacity recovery rate compared with the new capacity after deterioration was 89.38% (= 30.71 mAh ÷ 34.36 mAh × 100).

[Example 3]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) used the negative electrode peeling apparatus 31 of FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 80 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 3 hours, since the negative negative electrode active material layer portion was peeled off (step (1)), the negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2)). ). The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 80 ° C. until 3 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reusable laminate-type lithium ion secondary battery 1 created above was 42.78 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.86 mAh. The capacity retention rate was 72.14%. The capacity recovery rate compared to the new deteriorated capacity was 89.81% (= 30.86 mAh ÷ 34.36 mAh × 100).

[Example 4]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling apparatus 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 70 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 4 hours, since the negative electrode active material layer portion was peeled off (step (1)), the negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2)). The weight of the recovered product was 25.41 g, and the negative electrode material (negative electrode active material layer) was not observed on the copper foil current collector, and all the negative electrode material (negative electrode active material layer) was recovered. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 70 ° C. until 4 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the active material layer of the negative electrode thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the laminated lithium ion secondary battery 1 produced as described above was 42.80 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.89 mAh. The capacity retention rate was 72.17%. The capacity recovery rate compared with the new capacity after deterioration was 89.90% (= 30.89 mAh ÷ 34.36 mAh × 100).

[Example 5]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling apparatus 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 60 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 6 hours, since the negative electrode active material layer portion was peeled off (step (1)), the negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2)). . The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 60 ° C. until 6 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reuse laminated lithium ion secondary battery 1 produced above was 42.85 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.92 mAh. The capacity retention rate was 72.16%. The capacity recovery rate compared with the new capacity after deterioration was 89.99% (= 30.92 mAh ÷ 34.36 mAh × 100).

[Example 6]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 32 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 32 is a 5 L glass container. Propeller stirring can be performed through the stirring motor 19 of the stirring device, and the negative electrode 8 is partitioned by a stainless metal mesh 20 so that the negative electrode 8 does not hit the propeller 18, and the negative electrode 8 is inserted above the stainless metal mesh 20. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 100 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 0.1 hour, since the negative electrode active material layer portion was peeled off (step (1)), this negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2) )). The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 100 ° C. until 0.1 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reusable laminate-type lithium ion secondary battery 1 produced above was 42.45 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.52 mAh. The capacity retention rate was 71.90%. The capacity recovery rate compared with the new capacity after deterioration was 88.82% (= 30.52 mAh ÷ 34.36 mAh × 100).

[Example 7]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 32 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 32 is a 5 L glass container. Propeller stirring can be performed through the stirring motor 19 of the stirring device, and the negative electrode 8 is partitioned by a stainless metal mesh 20 so that the negative electrode 8 does not hit the propeller 18, and the negative electrode 8 is inserted above the stainless metal mesh 20. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 90 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 1.5 hours, since the negative electrode active material layer portion was peeled off (step (1)), the negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2) )). The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 90 ° C. until 1.5 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reuse laminated lithium ion secondary battery 1 produced above was 42.60 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.91 mAh. The capacity retention rate was 72.56%. The capacity recovery rate compared with the new capacity after deterioration was 89.96% (= 30.91 mAh ÷ 34.36 mAh × 100).

[Example 8]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 32 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 32 is a 5 L glass container. Propeller stirring can be performed through the stirring motor 19 of the stirring device, and the negative electrode 8 is partitioned by a stainless metal mesh 20 so that the negative electrode 8 does not hit the propeller 18, and the negative electrode 8 is inserted above the stainless metal mesh 20. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 80 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 2 hours, since the negative electrode active material layer portion was peeled off (step (1)), the negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2)). . The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 80 ° C. until 2 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reuse laminated lithium ion secondary battery 1 produced above was 42.81 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.88 mAh. The capacity retention rate was 72.13%. The capacity recovery rate compared with the new capacity after deterioration was 89.87% (= 30.88 mAh ÷ 34.36 mAh × 100).

[Example 9]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 32 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 32 is a 5 L glass container. Propeller stirring can be performed through the stirring motor 19 of the stirring device, and the negative electrode 8 is partitioned by a stainless metal mesh 20 so that the negative electrode 8 does not hit the propeller 18, and the negative electrode 8 is inserted above the stainless metal mesh 20. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 70 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 2.5 hours, since the negative electrode active material layer portion was peeled off (step (1)), this negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2) )). The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 70 ° C. until 2.5 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reuse laminated lithium ion secondary battery 1 produced above was 42.85 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.91 mAh. The capacity retention rate was 72.14%. The capacity recovery rate compared with the new capacity after deterioration was 89.96% (= 30.91 mAh ÷ 34.36 mAh × 100).

[Example 10]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 32 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 32 is a 5 L glass container. Propeller stirring can be performed through the stirring motor 19 of the stirring device, and the negative electrode 8 is partitioned by a stainless metal mesh 20 so that the negative electrode 8 does not hit the propeller 18, and the negative electrode 8 is inserted above the stainless metal mesh 20. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 60 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. After 5 hours, since the negative electrode active material layer portion was peeled off (step (1)), the negative electrode material (negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour (step (2)). . The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%. In step (1), the temperature of water (ion-exchanged water) 16 was kept at 60 ° C. until 5 hours after immersing (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reuse laminated lithium ion secondary battery 1 produced above was 42.89 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.95 mAh. The capacity retention rate was 72.16%. The capacity recovery rate compared with the new capacity after deterioration was 90.08% (= 30.95 mAh ÷ 34.36 mAh × 100).

[Example 11]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
In the production of the negative electrode, the same negative electrode as in Example 1 was used as the negative electrode for recovery.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling apparatus 33 shown in FIG. The pressure vessel 21 of the negative electrode peeling apparatus 33 is a 5 L stainless steel pressure vessel. 3 L of water (ion-exchanged water) was added thereto, and the heater 17 was heated so that the temperature of the water (ion-exchanged water) 16 was 100 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovered negative electrode (negative electrode) cut to 17 mm × 40 mm), covered with a pressure vessel lid 22 and heated under pressure (pressure heating water temperature) at 110 ° C. Left for a minute. Immediately after the pressure was released and the pressure vessel lid 22 was removed, the negative electrode active material layer portion was peeled off (step (1)), so this negative electrode material (negative electrode active material layer) was recovered and 110 ° C. And dried for 1 hour (step (2)). The weight of the recovered product was 25.41 g. In addition, the negative electrode material (negative electrode active material layer) did not adhere to the copper foil current collector, and all of the negative electrode material (negative electrode active material layer) was recovered and the recovery rate was 100%.

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like negative electrode material (negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and well stirred and mixed at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reuse laminated lithium ion secondary battery 1 produced above was 42.31 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.32 mAh. The capacity retention rate was 71.66%. The capacity recovery rate compared with the new capacity after deterioration was 88.24% (= 30.32 mAh ÷ 34.36 mAh × 100).

[Example 12]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The anode composition is such that the electrode composition ratio (mass ratio) is 94.5: 0.5: 5: active material (natural graphite), conductive assistant (carbon black), and binder (PVDF) ratio. I made it. First, an active material, a conductive additive, and a binder were weighed, an appropriate amount of NMP was added thereto, and the mixture was placed in a homogenizer container, and thoroughly stirred and mixed to prepare a slurry. Thereafter, a predetermined amount of this slurry was applied to one side of a negative electrode current collector (Cu foil; 200 mm × 290 mm) using a die coater so that the negative electrode active material layer portion had a size of 80 mm × 170 mm and dried. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer thus produced was 60 μm at the time of completion. The coating amount of the negative electrode (negative electrode active material layer weight) was 51.82% by mass of the negative electrode weight. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8. Note that a copper foil having a size (area) of 32 mm × 45 mm and a thickness of 10 μm was used for the negative electrode current collector.

<Production of battery>
A new battery was produced in the same manner as in Example 1.

<Deterioration treatment>
The laminated lithium ion secondary battery 1 produced above is a new article. This is the same as that produced in Example 1. The battery 1 was deteriorated by charging and discharging 300 times at 45 ° C. to obtain a deteriorated sample. The charge / discharge conditions are the same as in Example 1.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The battery subjected to the above deterioration treatment was discharged and rendered harmless. Here, the discharge for detoxification performed the process which reduces a cell voltage to 2.5V (below) by normal temperature (25 degreeC) and 1C discharge. Thereafter, the outer periphery of the laminate outer packaging material 14 was cut so as not to damage the positive and negative electrodes in the glove box, and the negative electrode 8 was collected. The negative electrode 8 was immersed in a beaker filled with ethyl alcohol for 30 minutes to dissolve the electrolytic solution and the deposit, and then rinsed again with fresh ethyl alcohol for about 1 minute. This was dried at 80 ° C. The negative electrode stripping device 32 shown in FIG. 4 was used to collect the deteriorated negative electrode material (used negative electrode active material layer). The peeling tank 15 of the negative electrode peeling apparatus 32 is a 5 L glass container. Propeller stirring can be performed through the stirring motor 19 of the stirring device, and the negative electrode (deteriorated negative electrode material) 8 is partitioned by a stainless wire mesh 20 so that it does not hit the propeller 18. ) 8 is inserted. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 100 ° C. To this, 50 g of a negative electrode recovery coated cut-out product (recovered deteriorated negative electrode cut to 15 mm × 40 mm (used negative electrode)) was added and allowed to stand. After 0.2 hours, since the negative electrode active material layer portion was peeled off (step (1)), this deteriorated negative electrode material (used negative electrode active material layer) was recovered and dried at 110 ° C. for 1 hour ( Step (2)). The weight of the recovered product was 25.41 g. In addition, the negative electrode material (used negative electrode active material layer) did not adhere to the copper foil current collector, and all of the deteriorated negative electrode material (used negative electrode active material layer) was recovered and the recovery rate was 100%. Met. In step (1), the temperature of water (ion-exchanged water) 16 was maintained at 100 ° C. until 0.2 hours after peeling (peeling).

(Preparation of negative electrode using negative electrode recovery material)
The recovered film-like deteriorated negative electrode material (used negative electrode active material layer) and NMP were weighed, placed in a homogenizer container, and stirred and mixed well at 70 ° C. to prepare a slurry. Then, a certain amount of this slurry was applied to one side of the negative electrode current collector 5 (Cu foil; 200 mm × 290 mm) using a die coater so that the portion of the negative electrode active material layer 7 was 80 mm × 170 mm in size and dried. did. Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. The portion of the negative electrode active material layer 7 was cut out to have a size of 32 mm × 45 mm. As shown in FIG. 1, a nickel tab as a negative electrode tab (current collector plate) 3 is joined by ultrasonic welding to one end of a negative electrode current collector 5 where the negative electrode active material layer 7 is not formed (electrical). To the negative electrode (negative electrode) 8 was obtained (step (3)).

<Production of battery>
The reusable battery was produced in the same manner as in Example 1.

<Battery capacity>
The capacity of Example 1 was applied as the capacity of the new battery.

  The initial capacity of the negative electrode reuse laminated lithium ion secondary battery 1 produced above was 42.25 mAh. When this battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 29.955 mAh. The capacity retention rate was 70.89%. The capacity recovery rate compared with the new capacity after deterioration was 87.17% (= 29.955 mAh ÷ 34.36 mAh × 100).

[Comparative Example 1]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

(Preparation of collection negative electrode)
The anode composition is such that the electrode composition ratio (mass ratio) is an active material (natural graphite), a conductive additive (carbon black), an aqueous (water dispersion) binder (SBR), and an additive (CMC). .7: 0.3: 2: 1. First, an active material, a conductive additive, an aqueous (water dispersion) binder, and an additive were weighed, added with water, placed in a homogenizer container, and stirred and mixed well to prepare an aqueous slurry. Thereafter, a certain amount of this aqueous slurry was applied to one side of a negative electrode current collector (Cu foil; 200 mm × 290 mm) using a die coater so that the negative electrode active material layer portion was 80 mm × 170 mm in size and dried. . Then, it pressed with the roll press. It dried for 8 hours with the 130 degreeC vacuum dryer. The thickness (one side) of the negative electrode active material layer 7 thus produced was 60 μm at the time of completion. A coating portion (80 mm × 170 mm) of this negative electrode was cut out. This coated cut-out product was used as a negative electrode for recovery (negative electrode). The recovery negative electrode (negative electrode) was 51.82% by mass of the negative electrode weight.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 100 ° C. To this was added 50 g of the above-described negative electrode recovery coating cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. However, no peeling of the negative electrode material (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature at 100 ° C. while controlling the temperature with the heater 17), the sample was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 2]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The recovery negative electrode was prepared using an aqueous slurry using an aqueous (aqueous dispersion) binder (SBR), as in Comparative Example 1.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 90 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Comparative Example 1) and left to stand. However, no peeling of the (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature at 90 ° C. while controlling the temperature with the heater 17), the sample was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 3]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The recovery negative electrode was prepared using an aqueous slurry using an aqueous (aqueous dispersion) binder (SBR), as in Comparative Example 1.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 80 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Comparative Example 1) and left to stand. However, no peeling of the (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature at 80 ° C. while controlling the temperature with the heater 17), the sample was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 4]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The recovery negative electrode was prepared using an aqueous slurry using an aqueous (aqueous dispersion) binder (SBR), as in Comparative Example 1.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of water (ion-exchanged water) 16 was added, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 70 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Comparative Example 1) and left to stand. However, no peeling of the (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature at 70 ° C. while controlling the temperature with the heater 17), the sample was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 5]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The same recovery negative electrode as in Example 1 was used.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of ethyl alcohol was added and heated and held by the heater 17 so that the temperature of the ethyl alcohol was 78 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Example 1) and allowed to stand. However, no peeling of the negative electrode material (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while the temperature of the ethyl alcohol was maintained at 78 ° C. while controlling the temperature with the heater 17), the sample was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 6]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The same recovery negative electrode as in Example 1 was used.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of ethyl alcohol was added and heated and held by the heater 17 so that the temperature of the ethyl alcohol was 70 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Example 1) and allowed to stand. However, no peeling of the negative electrode material (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while the temperature of the ethyl alcohol was maintained at 70 ° C. while controlling the temperature with the heater 17), it was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 7]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The same recovery negative electrode as in Example 1 was used.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of n-propanol was added, and heated and held by the heater 17 so that the temperature of n-propanol was 97 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Example 1) and allowed to stand. However, no peeling of the negative electrode material (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature of n-propanol at 97 ° C. while controlling the temperature with the heater 17), the sample was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 8]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The same recovery negative electrode as in Example 1 was used.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of n-propanol was added, and heated and held by the heater 17 so that the temperature of n-propanol was 80 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Example 1) and allowed to stand. However, no peeling of the negative electrode material (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature of n-propanol at 80 ° C. while controlling the temperature with the heater 17), the sample was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 9]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The same recovery negative electrode as in Example 1 was used.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of isopropanol was added and heated and held by the heater 17 so that the temperature of isopropanol was 80 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Example 1) and allowed to stand. However, no peeling of the negative electrode material (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature of isopropanol at 80 ° C. while controlling the temperature with the heater 17), heating was continued for 8 hours in the same manner, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 10]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The same recovery negative electrode as in Example 1 was used.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 31 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 31 is a 5 L glass container. 3 L of isopropanol was added and heated and held by the heater 17 so that the temperature of isopropanol was 70 ° C. To this was added 50 g of the above-mentioned negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm; see Example 1) and allowed to stand. However, no peeling of the negative electrode material (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature of isopropanol at 70 ° C. while controlling the temperature with the heater 17), heating was continued for 8 hours in the same manner, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

[Comparative Example 11]
<Preparation of positive electrode>
The positive electrode was the same as in Example 1.

<Production of negative electrode>
The same recovery negative electrode as in Example 1 was used.

(Recovery of negative electrode material (negative electrode active material layer) for reuse)
The negative electrode material (negative electrode active material layer) was collected using the negative electrode peeling device 32 shown in FIG. The peeling tank 15 of the negative electrode peeling apparatus 32 is a 5 L glass container. Propeller stirring can be performed through the stirring motor 19 of the stirring device, and the negative electrode 8 is partitioned by a stainless metal mesh 20 so that the negative electrode 8 does not hit the propeller 18, and the negative electrode 8 is inserted above the stainless metal mesh 20. 3 L of water (ion-exchanged water) 16 was added thereto, and heated and held by the heater 17 so that the temperature of the water (ion-exchanged water) 16 was 50 ° C. To this was added 50 g of a negative electrode recovery coated cut-out product (recovery negative electrode (negative electrode) cut to 17 mm × 40 mm) and left to stand. However, no peeling of the negative electrode material (negative electrode active material layer) was observed even after 8 hours. (Intermediately, while maintaining the temperature of water (ion-exchanged water) 16 at 50 ° C. while controlling the temperature with the heater 17), the sample was continuously heated and held for 8 hours, but no peeling was observed. Although it was immersed and heated for a total of 120 hours, peeling did not occur, and the negative electrode material (negative electrode active material layer) could not be recovered. For this reason, production of a negative electrode using a negative electrode collection material (film-like negative electrode active material layer), production of a battery, and confirmation of the capacity of the battery could not be carried out.

  The results of Examples 1 to 12 and Comparative Examples 1 to 11 are shown in Table 1.

  The operational effects of the first embodiment are as follows.

  In Example 1, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed in water (ion-exchanged water) 16 at 100 ° C. using the peeling device 31 of FIG. The (negative electrode active material layer) is peeled (peeled in 0.2 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. Thereafter, the recovered negative electrode material (film-like negative electrode active material layer) is put in a homogenizer, NMP (N-methyl-2-pyrrolidone: hereinafter referred to as NMP) is added, and the mixture is stirred and slurried to form a current collector. It is applied to a current collector of copper foil and is again made into a negative electrode. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.42 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.5 mAh. The capacity retention rate was 71.9%. The initial capacity of the laminate type lithium ion secondary battery 1 made of a new negative electrode and a new positive electrode was 45.78 mAh. When this was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 34.36 mAh. The capacity recovery rate after deterioration of the reused battery was 88.77%, and it was confirmed that a high capacity recovery rate was obtained.

  Of the 300 charge / discharge conditions including the initial charge / discharge, the charge condition is 45 ° C. and constant current / constant voltage method (CCCV, current: 1 C, cell voltage: 4.2 V) for a total of 2.5 hours. The charging process was performed. The discharge conditions were 45 ° C. and a constant current method (CC, current: 1 C).

  The operational effects of the second embodiment are as follows.

  In Example 2, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed in water (ion-exchanged water) 16 at 90 ° C. using the peeling device 31 of FIG. The (negative electrode active material layer) is peeled off (peeled in 2 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.55 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.71 mAh. The capacity retention rate was 72.17%. The capacity recovery rate after deterioration of the reused battery was 89.38%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the third embodiment are as follows.

  In Example 3, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed in water (ion-exchanged water) 16 at 80 ° C. using the peeling device 31 of FIG. The (negative electrode active material layer) is peeled (peeled in 3 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.78 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.86 mAh. The capacity retention rate was 72.147%. The capacity recovery rate after deterioration of the reused battery was 89.81%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the fourth embodiment are as follows.

  In Example 4, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed in water (ion-exchanged water) 16 at 70 ° C. using the peeling device 31 of FIG. The (negative electrode active material layer) is peeled off (peeled in 4 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.80 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.89 mAh. The capacity retention rate was 72.17%. The capacity recovery rate after deterioration of the reused battery was 89.90%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the fifth embodiment are as follows.

  In Example 5, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed in water (ion-exchanged water) 16 at 60 ° C. using the peeling device 31 of FIG. The (negative electrode active material layer) is peeled off (peeled in 6 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.85 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.92 mAh. The capacity retention rate was 72.16%. The capacity recovery rate after deterioration of the reused battery was 89.99%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the sixth embodiment are as follows.

  In Example 6, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed and stirred in 100 ° C. water (ion-exchanged water) 16 using the peeling device 32 of FIG. The material (negative electrode active material layer) is peeled (peeled in 0.1 hour), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.45 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.52 mAh. The capacity retention rate was 71.90%. The capacity recovery rate after deterioration of the reused battery was 89.82%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the seventh embodiment are as follows.

  In Example 7, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed and stirred in 90 ° C. water (ion-exchanged water) 16 using the peeling device 32 of FIG. The material (negative electrode active material layer) is peeled off (peeled in 1.5 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a copper foil current collector as a current collector, and again the negative electrode It has become. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.60 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.91 mAh. The capacity retention rate was 72.56%. The capacity recovery rate after deterioration of the reused battery was 89.96%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the eighth embodiment are as follows.

  In Example 8, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed and stirred in 80 ° C. water (ion-exchanged water) 16 using the peeling device 32 of FIG. The material (negative electrode active material layer) is peeled off (peeled in 2 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.81 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.88 mAh. The capacity retention rate was 72.13%. The capacity recovery rate after deterioration of the reused battery was 89.87%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the ninth embodiment are as follows.

  In Example 9, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed and stirred in 70 ° C. water (ion-exchanged water) 16 using the peeling device 32 of FIG. The material (negative electrode active material layer) was peeled off (peeled in 2.5 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.85 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.91 mAh. The capacity retention rate was 72.14%. The capacity recovery rate after deterioration of the reused battery was 89.96%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the tenth embodiment are as follows.

  In Example 10, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed and stirred in 60 ° C. water (ion-exchanged water) 16 using the peeling device 32 of FIG. The material (negative electrode active material layer) was peeled (peeled in 5 hours), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.89 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.95 mAh. The capacity retention rate was 72.16%. The capacity recovery rate after deterioration of the reused battery was 90.08%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of Example 11 are as follows.

  In Example 11, an unused negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was immersed in water (ion-exchanged water) 16 at 110 ° C. (pressure heating) using the peeling device 33 of FIG. Then, the negative electrode material (negative electrode active material layer) is peeled (peeled in 0.1 hour), collected, and dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.31 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 30.32 mAh. The capacity retention rate was 71.66%. The capacity recovery rate after deterioration of the reused battery was 88.24%, and it was confirmed that a high capacity recovery rate was obtained.

  The operational effects of the twelfth embodiment are as follows.

  In Example 12, a used negative electrode (binder: non-aqueous (organic solvent) PVDF binder) was used.

  The used negative electrode was deteriorated by charging and discharging a new laminate-type lithium ion secondary battery 1 at 45 ° C. 300 times. The battery subjected to this treatment was discharged and rendered harmless. Here, the discharge for detoxification performed the process which reduces a cell voltage to 2.5V (below) by normal temperature (25 degreeC) and 1C discharge. Thereafter, the outer periphery of the laminate outer package 14 was cut so as not to damage the positive and negative electrodes in the glove box, and the negative electrode was collected. This negative electrode was immersed in a beaker filled with ethyl alcohol for 30 minutes to dissolve the electrolytic solution and the deposit, and then rinsed again with fresh ethyl alcohol for about 1 minute. This was dried at 80 ° C. The negative electrode is immersed and stirred in water (ion-exchanged water) 16 at 100 ° C. using the peeling device 32 of FIG. And dried. The negative electrode material (negative electrode active material layer) peeled off as a film, and the recovery rate of the negative electrode material (negative electrode active material layer) was 100%. After that, the recovered negative electrode material (film-like negative electrode active material layer) is put into a homogenizer, NMP is added, mixed with stirring, slurried, applied to a current collector of copper foil as a current collector, and again converted into a negative electrode It is a thing. A battery was assembled using the reused negative electrode and a new positive electrode. The initial capacity of the reuse laminated lithium ion secondary battery 1 produced as described above was 42.25 mAh. When the battery 1 was deteriorated by charging and discharging 300 times at 45 ° C., the capacity was 29.95 mAh. The capacity retention rate was 70.89%. The capacity recovery rate after deterioration of the reused battery was 87.17%, and it was confirmed that a high capacity recovery rate was obtained.

  In the examples, natural graphite was used as the active material of the negative electrode material (negative electrode active material layer), and carbon black was used as the conductive aid, but other negative electrode active materials and conductive aids were used. Of course, it is also good.

  Further, in Example 5 to Example 10, a propeller stirring device was used as a peeling device, but stirring is not limited to a propeller, such as by blowing air or by a stirrer using a magnetic stirrer, etc. Of course, any device capable of stirring can be used.

  In Comparative Example 1 to Comparative Example 4, those using an aqueous (water dispersion) SBR binder as the binder of the negative electrode material for recovery were prepared. These negative electrodes were placed in the peeling device 31 of FIG. 3, water was added, and the mixture was left to stand at 100 ° C. In addition, water was added and left to stand at 90 ° C, water was added and left to stand at 80 ° C, and water was added and left to stand at 70 ° C. I couldn't.

  In Comparative Examples 5 to 6, the same negative electrode material as in Example 1 was used as the recovery negative electrode material.

  These negative electrodes were placed in the peeling apparatus 31 shown in FIG. Moreover, what added ethyl alcohol and was left to heat at 70 degreeC was implemented. However, no peeling was observed even in 120 hours.

  In Comparative Examples 7 to 8, the same negative electrode material for recovery as that of Example 1 was used.

  These negative electrodes were put into the peeling apparatus 31 of FIG. 3, n-propanol was added, and it was left to heat at 97 ° C. Moreover, what added n-propanol and was left to heat at 80 degreeC was implemented. However, no peeling was observed even in 120 hours.

  In Comparative Examples 9 to 10, the same negative electrode material as in Example 1 was used as the recovery negative electrode material.

  These negative electrodes were placed in the peeling device 31 of FIG. 3, isopropanol was added, and the mixture was left standing at 80 ° C. Moreover, the thing which added isopropanol and left to heat at 70 degreeC was also implemented. However, no peeling was observed even in 120 hours.

  In Comparative Example 11, the same negative electrode material for recovery as in Example 1 was used.

  These negative electrodes were put into the peeling apparatus 32 of FIG. 4, water (ion exchange water) 16 was added, and it heated and stirred at 50 degreeC. However, no peeling was observed even after 120 hours.

  It is considered that peeling of the negative electrode material (negative electrode active material layer) with water in the examples is caused by the following action. That is, the negative electrode active material layer is a layer having voids. The adhesion portion with the current collector is formed by a non-aqueous (organic solvent) binder (PVDF), but is formed by an aggregate of points and line contacts. At room temperature, the current collector and the active material are not peeled off, but PVDF softens as the temperature rises, and the adhesive strength of PVDF also decreases. In addition, the surface tension of water decreases as the temperature rises, making it easy for water to enter the adhesive interface and leading to peeling. This tendency increases as the temperature rises, and the time until peeling becomes shorter. At 100 ° C., the water that has entered the interface becomes steam, so that the force to lift and peel off the negative electrode active material layer increases, and the separation takes place in about 10 minutes.

  Further, when the stirring is performed, the peeling time is shortened. This is considered to be because the water hits the interface (cross section) between the negative electrode layer and the current collector to cause a physical peeling force.

  In Comparative Example 11, it did not peel off, but because the temperature of the aqueous solution was 50 ° C., the non-aqueous (organic solvent) binder (PVDF) was not sufficiently softened and could not enter the water interface. It is thought that it will lead to peeling.

  In Comparative Examples 1 to 4, a negative electrode material (negative electrode active material layer) using an aqueous (water-dispersed) SBR binder as a bander was used, but it did not peel off. It is considered that this is because the water-based (water-dispersed) binder (SBR) of the binder is cross-linked to form a three-dimensional structure so that water cannot enter. Further, it is considered that the adhesive strength is larger than that of a non-aqueous (organic solvent) binder (PVDF). For this reason, the invention of a new peeling method is required for the SBR binder.

  In Comparative Examples 5 to 10, the same negative electrode material as in Example 1 was used as the recovery negative electrode material.

  These negative electrodes were put in the peeling apparatus 31 of FIG. 3, and ethyl alcohol and n-propanol i-propanol were added and left to stand at various temperatures. However, no peeling was observed even in 120 hours. This is probably because ethyl alcohol, n-propanol, and i-propanol have larger molecules than water and cannot enter the adhesion interface.

1 laminated battery (LIB, laminated lithium secondary battery),
2 power generation elements,
3 Negative electrode tab (current collector plate),
4 Positive electrode tab (current collector plate),
5 negative electrode current collector,
6 positive current collector,
7 negative electrode active material layer,
8 negative electrode (= negative electrode; negative electrode current collector + negative electrode active material layer (+ negative electrode tab)),
9 positive electrode active material layer,
10 separator,
11 Electrolyte layer (separator + electrolyte solution (quality)),
12 positive electrode (= positive electrode; positive electrode current collector + positive electrode active material layer (+ positive electrode tab)),
13 cell layer,
14 exterior body (laminate sheet),
15 peeling tank,
16 Stripping solution (aqueous solution),
17 Heater (heating device),
18 propellers (stirring roots),
19 stirring motor,
20 stainless steel mesh,
21 stainless steel pressure vessel,
22 Stainless steel pressure vessel lid,
23 Pressure regulating valve,
24 sealing member,
31, 32, 33 Negative electrode peeling apparatus.

Claims (4)

A step (1) of immersing a negative electrode having a negative electrode active material layer containing a non-aqueous binder and a current collector in an aqueous solution having a temperature higher than 50 ° C .;
Recovering the peeled negative electrode active material layer (2);
A step (3) of attaching the recovered negative electrode active material layer to the current collector again, and a method of reusing the negative electrode active material layer of the lithium ion battery.   The method for reusing a negative electrode active material layer of a lithium ion battery according to claim 1, wherein the temperature of the aqueous solution in the step (1) is 60 ° C. or higher.   The method for reusing a negative electrode active material layer of a lithium ion battery according to claim 1 or 2, wherein the step (1) includes a step of stirring.   A method for producing a reusable battery, comprising using the negative electrode obtained by the method for reusing a negative electrode active material layer of a lithium ion battery according to claim 1.