Method for recovering electrode material

Abstract

To provide a method for recovering an electrode material.SOLUTION: There is provided a method for recovering an electrode material, which provides an electrode laminate roll 21 in which an electrode laminate 11 is wound, the electrode laminate including a current collector foil 12 and an electrode material 13 laminated on at least one surface of the current collector foil 12. The method includes: unwinding the electrode laminate 11 from the electrode laminate roll 21 and transporting the electrode laminate in a longitudinal direction; supplying moisture to the electrode material 13; freezing moisture supplied to the electrode material 13; and crushing the electrode material 13 and separating the electrode material from the current collector foil 12, by applying a mechanical impact to the electrode material 13 with frozen moisture and blowing a gas 33.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for recovering electrode materials.

Background Art

[0002] After use of a primary battery or a secondary battery such as a lithium-ion battery, it is considered to disassemble it and recover and recycle electrode materials such as a positive electrode composite layer (positive electrode active material layer) and a negative electrode composite layer (negative electrode active material layer).

[0003] Note that Patent Document 1 discloses a method for recovering a catalyst from an object in which a catalyst layer is formed on the surface of an electrolyte membrane or a diffusion layer for a fuel cell. The method includes a step of peeling the catalyst from the electrolyte membrane or the diffusion layer by colliding a solid particle group such as dry ice particles or ice particles with the catalyst layer formed on the surface of the electrolyte membrane or the diffusion layer, and a step of recovering the peeled catalyst.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, after use of a primary battery or a secondary battery, it is considered to disassemble it and recover and recycle electrode materials. On the other hand, in the manufacturing stage of a primary battery or a secondary battery, when forming an electrode laminate by laminating an electrode material on a current collector foil, defects may occur and the obtained electrode laminate may not be usable. The present inventors have found that it is preferable to recover electrode materials from such unusable electrode laminates generated in the battery manufacturing stage.

[0006] The present disclosure has been made in view of such points, and provides a method for recovering an electrode material.

Means for Solving the Problems

[0007] <Aspect 1> A method for recovering an electrode material, including the following steps: Providing an electrode laminate, where the electrode laminate has a current collector foil and an electrode material laminated on at least one surface of the current collector foil; Supplying moisture to the electrode material; Freezing the moisture supplied to the electrode material, and Crushing the electrode material by applying mechanical shock to the electrode material in which the moisture is frozen and blowing a gas, and separating the electrode material from the current collector foil. <Aspect 2> The method according to Aspect 1, where the electrode laminate is unwound from an electrode laminate roll around which the electrode laminate is wound and conveyed in the longitudinal direction. <Aspect 3> The method according to Aspect 1 or 2, where the supply of the moisture is performed by bringing a sponge containing moisture into contact with the electrode material. <Aspect 4> The method according to any one of Aspects 1 to 3, where the freezing of the moisture and the application of mechanical shock to the electrode material are performed by relatively passing the electrode laminate between two cooling rollers provided with irregularities on the surface. <Aspect 5> It has a touch roll for adjusting the tension of the electrode laminate upstream of the position where the moisture is supplied and downstream of the position where the gas is blown, whereby at the position where the moisture is supplied to the electrode laminate, the position where the moisture is frozen, the position where mechanical shock is applied to the electrode material, and the position where the gas is blown, tension is applied to the electrode laminate. The method according to any one of Aspects 1 to 4. <Aspect 6> The method according to any one of Aspects 1 to 5, where the gas is dry air, nitrogen gas, or carbon dioxide. <Aspect 7> The method according to any one of Aspects 1 to 6, wherein the gas is a heated gas. <Aspect 8> The method according to any one of Aspects 1 to 7, further comprising winding the separated current collector foil with the electrode material using a winding roll to provide a current collector foil roll. [Advantages of the Invention]

[0008] According to the present disclosure, a method for recovering an electrode material can be provided. [Brief Description of the Drawings]

[0009]

Figure 1

Figure 2

[0010] The method of the present disclosure for recovering an electrode material may be a method for separating and recovering an electrode material of a primary battery or a secondary battery, for example, a lithium-ion primary battery or a secondary battery, from a current collector foil. Here, the electrode material (active material) may be a positive electrode composite material (positive electrode active material) or a negative electrode composite material (negative electrode active material), and particularly may be a positive electrode composite material. Therefore, according to the method of the present disclosure, the positive electrode active material or the negative electrode active material, particularly the positive electrode active material, can be recovered and recycled.

[0011] FIG. 1 is a schematic diagram for explaining one form of the method of the present disclosure for recovering an electrode material. Hereinafter, the method of the present disclosure shown in FIG. 1 will be specifically described, but the method of the present disclosure is not limited to this embodiment.

[0012] (Providing an electrode laminate roll) In the method of the present disclosure, an electrode laminate 11 is provided. The electrode laminate has a current collector foil 12 and an electrode material 13 laminated on at least one surface of the current collector foil.

[0013] The current collector foil may be, for example, a metal foil containing aluminum. The metal foil may be an aluminum foil, a metal foil such as SUS, Cu, Ni, Fe, Ti, Co, or Zn, a foil using a clad material of a metal such as SUS, Cu, Ni, Fe, Ti, Co, or Zn and Al, or a foil having Al coated on the metal surface.

[0014] The electrode material may be a positive electrode composite material (positive electrode active material) or a negative electrode composite material (negative electrode active material), and particularly may be a positive electrode composite material. For example, the positive electrode composite material may contain an oxide active material, a sulfide active material, etc. Further, the electrode material may contain a binder such as PESE (polyethylene sebacate), PPSU (polyphenyl sulfone), PBI (polybenzimidazole), PESU (polyethersulfone). Further, the electrode material may contain a carbon material such as acetylene black, furnace black, channel black, thermal black, activated carbon, carbon, carbon fiber, graphite.

[0015] The electrode laminate 11 may be unwound from the electrode laminate roll 21 and conveyed in the longitudinal direction. In the present disclosure, the "longitudinal direction" means the length direction of the electrode laminate 11, that is, the direction in which the electrode laminate 11 is wound around the electrode laminate roll 21.

[0016] The unwinding of the electrode laminate from the electrode laminate roll can be performed by any known method. For example, the electrode laminate roll is rotated using a motor, and the unwound electrode laminate can be conveyed while being supported by a support roller or in a state of floating in the air.

[0017] (Supply of moisture to the electrode material) In the method of the present disclosure, moisture is supplied to the electrode material.

[0018] The supply of moisture may be carried out by spraying, coating, dipping, or the like. The supply of moisture may also be carried out by bringing a sponge roll 31 containing moisture into contact with the electrode material.

[0019] When the amount of moisture increases, the electrode material is likely to become slurry after recovery, so the amount of moisture in the electrode material is preferably 20% or less. The amount of moisture can be defined as the value obtained by subtracting the percentage of solids measured using a general solid content measuring device from 100%. After supplying moisture, wiping may be performed to adjust the amount of moisture.

[0020] (Freezing of moisture) In the method of the present disclosure, the moisture supplied to the electrode material 13 is frozen.

[0021] Freezing can be carried out by a cooling roller, a cooling plate, a low-temperature atmosphere, dry ice, liquid nitrogen, etc., particularly by a cooling roller. Here, the cooling roller and the cooling plate are a cooled roller and a plate, respectively, and mean those capable of freezing the moisture supplied to the electrode material by contacting the electrode material.

[0022] When the moisture supplied to the electrode material 13 freezes, due to the volume expansion of water, a large number of cracks are generated in the electrode material, and the binding of the electrode material can be broken. In addition, the electrode laminate becomes low in temperature, and the resin component in the electrode material shrinks, hardens, and becomes brittle, thereby promoting the crushing of the electrode material and the separation of the electrode material from the current collector foil.

[0023] (Separation of electrode material) In the method of the present disclosure, the electrode material 13 that has been frozen with moisture is subjected to mechanical impact and gas 33 is blown thereto, thereby crushing the electrode material 13 and separating it from the current collector foil 12.

[0024] The application of mechanical impact may be by scraping with a blade, impact by vibration, shot blasting, etc., compression by a roll, vibration, etc.

[0025] After applying mechanical shock to the electrode material, a gas is blown onto the electrode laminate. By blowing the gas after applying the mechanical shock in this way, crushing of the electrode material and separation of the electrode material from the electrode laminate can be promoted.

[0026] Freezing of the moisture supplied to the aforementioned electrode material 13 and application of mechanical shock to the electrode material may be performed simultaneously. For example, it may be performed by passing the electrode laminate 11 relatively between two cooling rollers 32 provided with unevenness on the surface. The relative passage of the electrode laminate 11 may be performed by conveying the electrode laminate 11. The relative passage of the electrode laminate 11 may be performed by moving the two cooling rollers 32. The relative passage of the electrode laminate 11 may be performed by moving both the electrode laminate 11 and the two cooling rollers 32.

[0027] By blowing the gas 33 onto the electrode material, the electrode material 13 peeled off from the current collector foil is separated from the current collector foil. The separated electrode material is blown away by the blown gas, and only the current collector foil 12 from which the electrode material has peeled off remains. In a preferred embodiment, the gas blown here can promote the separation of the electrode material from the current collector foil, promote the vaporization of the moisture contained in the electrode material, and thereby reduce the moisture content of the obtained electrode material. The reduction in the moisture content of the obtained electrode material may be preferable for suppressing the obtained electrode material from becoming slurried.

[0028] The gas 33 blown onto the electrode laminate may be dry air, that is, air that has undergone a process of removing moisture. The gas may be nitrogen or carbon dioxide. Also, the gas may be a heated gas. Here, the heated gas does not necessarily mean a high-temperature gas, but rather a gas that has been heated to some extent. If the gas is a heated gas, it is preferable because the vaporization of the moisture contained in the electrode material is promoted, and thereby the moisture content of the electrode material can be easily lowered.

[0029] These processes may be carried out in an inert gas atmosphere, particularly in a nitrogen atmosphere or a carbon dioxide atmosphere. When these processes are carried out in such an inert gas atmosphere, deterioration of the active material contained in the electrode material can be suppressed. Further, when these processes are carried out in a carbon dioxide active atmosphere, metal lithium or the like contained in the electrode material can be carbonated and stabilized with carbon dioxide.

[0030] The material 13a separated from the current collector foil 12 may be, for example, dropped and separately recovered. The recovered material may be directly, or after treatments such as drying, washing and purification, re-slurried by adding a solution such as an NMP (N-methyl-2-pyrrolidone) solution, and used again for coating the electrode material.

[0031] Using FIG. 2, the process of supplying moisture to the electrode material, freezing the moisture, applying mechanical shock, and thereby crushing the electrode material to separate it from the current collector foil will be described. The electrode laminate 11 has a current collector foil 12 and an electrode material 13 (FIG. 2(a)). In the method of the present disclosure, moisture is supplied to the electrode material 13 (FIG. 2(b)). Next, the moisture in the electrode material 13 is frozen. As a result, due to the volume expansion of water, a large number of cracks are generated in the electrode material, and the binding of the electrode material collapses (FIG. 2(c)). Thereafter, mechanical shock is applied to the electrode material 13 in which the moisture is frozen, and by blowing a gas, the electrode material 13 is crushed and separated from the current collector foil 12, and the material 13a is recovered (FIG. 2(d)).

[0032] (Application of tension) There is a touch roll 41 for adjusting the tension of the electrode laminate 11 upstream of the position where moisture is supplied to the electrode laminate 11 and downstream of the position where the gas 33 is blown onto the electrode laminate 11, whereby moisture is supplied to the electrode laminate, at the position where the moisture is frozen, at the position where mechanical shock is applied to the electrode material, and when the gas 33 is blown, tension may be applied to the electrode laminate 11.

[0033] Such application of tension is preferable for suppressing the flutter of the electrode laminate when the gas is blown.

[0034] (Winding of current collector foil) The current collector foil 12 from which the electrode material has peeled off may be wound by the winding roll 22 to form a current collector foil roll. Since the electrode material has been removed from the wound current collector foil, it may be reused as a metal foil.

[0035] Although one embodiment of the present disclosure has been described in detail above, the present disclosure is not limited to the foregoing embodiment, and various design changes can be made without departing from the spirit of the present disclosure.

Explanation of reference numerals

[0036] 11 Electrode laminate 12 Current collector foil 13, 13a Electrode material 21 Electrode laminate roll 22 Winding roll 31 Sponge roll 32 Cooling roller 33 Gas 41 Touch roll

Claims

1. A method for recovering an electrode material, comprising the following steps: Providing an electrode laminate, wherein the electrode laminate has a current collector foil and an electrode material laminated on at least one surface of the current collector foil; Unwinding the electrode laminate from an electrode laminate roll on which the electrode laminate is wound and conveying it in the longitudinal direction; Supplying moisture to the electrode material; Freezing the moisture supplied to the electrode material; and Crushing the electrode material by applying mechanical shock to the electrode material with the frozen moisture and blowing a gas, thereby separating the electrode material from the current collector foil.

2. A method for recovering an electrode material, comprising the following steps: Providing an electrode laminate, wherein the electrode laminate has a current collector foil and an electrode material laminated on at least one surface of the current collector foil; Supplying moisture to the electrode material; Freezing the moisture supplied to the electrode material; and Crushing the electrode material by applying mechanical shock to the electrode material with the frozen moisture and blowing a gas, thereby separating the electrode material from the current collector foil, wherein the freezing of the moisture and the application of mechanical shock to the electrode material are performed by passing the electrode laminate relatively between two cooling rollers provided with unevenness on their surfaces.

3. A method for recovering an electrode material, comprising the following steps: Providing an electrode laminate, wherein the electrode laminate has a current collector foil and an electrode material laminated on at least one surface of the current collector foil; Supplying moisture to the electrode material; Freezing the moisture supplied to the electrode material; and Crushing the electrode material by applying mechanical shock to the electrode material with the frozen moisture and blowing a gas, thereby separating the electrode material from the current collector foil, wherein there are touch rollers for adjusting the tension of the electrode laminate upstream of the position where the moisture is supplied and downstream of the position where the gas is blown, whereby tension is applied to the electrode laminate at the position where the moisture is supplied to the electrode laminate, the position where the moisture is frozen, the position where mechanical shock is applied to the electrode material, and the position where the gas is blown.

4. A method for recovering an electrode material, comprising the following steps: Providing an electrode laminate, wherein the electrode laminate has a current collector foil and an electrode material laminated on at least one surface of the current collector foil; Supplying moisture to the electrode material, freezing the moisture supplied to the electrode material, and crushing the electrode material and separating it from the current collector foil by applying mechanical shock to the electrode material with the frozen moisture and blowing a gas thereonto, where the gas is a heated gas.

5. A method for recovering an electrode material, comprising the following steps: Providing an electrode laminate, where the electrode laminate has a current collector foil and an electrode material laminated on at least one surface of the current collector foil, Supplying moisture to the electrode material, freezing the moisture supplied to the electrode material, and crushing the electrode material and separating it from the current collector foil by applying mechanical shock to the electrode material with the frozen moisture and blowing a gas thereonto, providing a current collector foil roll by winding up the current collector foil from which the electrode material has been separated with a winding roll.

6. The method according to any one of claims 1 to 5, wherein the supply of the moisture is performed by bringing a sponge containing moisture into contact with the electrode material.

7. The method according to any one of claims 1 to 5, wherein the gas is dry air, nitrogen, or carbon dioxide.

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