Bipolar battery and method for manufacturing recycled material

Abstract

To provide a bipolar battery easy to be disassembled.SOLUTION: The bipolar battery includes a plurality of bipolar electrodes and a sealing material. The plurality of bipolar electrodes are stacked in the surface-perpendicular direction. Each of the plurality of bipolar electrodes includes a positive electrode layer, a collector foil, and a negative electrode layer in this order in a through-plane direction. In the in-plane direction, the current collector foil extends outward as compared with the positive electrode layer and the negative electrode layer. The seal material is joined to the current collector foil at the end in the in-plane direction, thereby sealing between the current collector foils adjacent to each other in the through-plane direction. (1) The collector foils have an absorptance of 50% or more and the seal material has an absorptance of 10% or less with respect to lasers having wavelengths of 400 to 532nm. (2) Alternatively, the collector foils have an absorptance of 50% or more and the seal material has an absorptance of 10% or less with respect to lasers having wavelengths of 930 to 1064nm.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to bipolar batteries and methods for producing recycled materials. [Background technology]

[0002] Japanese Patent Application Laid-Open No. 2003-170290 discloses a laser beam transmission welding method. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-170290 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need to recover various materials from discarded batteries and recycle them, which has led to a demand for batteries that are easy to disassemble.

[0005] Bipolar batteries that are divided into multiple cells by sealing the spaces between the bipolar electrodes are being considered. These bipolar batteries tend to have large sealed areas. From the perspective of ease of disassembly, it is desirable for the sealing material to be easily separated from the bipolar electrodes.

[0006] An object of the present disclosure is to provide a bipolar battery that is easy to disassemble. [Means for solving the problem]

[0007] 1. One aspect of the present disclosure is a bipolar battery. The bipolar battery includes a plurality of bipolar electrodes and a sealing material. The bipolar electrodes are stacked in a direction perpendicular to the surface. Each of the bipolar electrodes includes a positive electrode layer, a current collecting foil, and a negative electrode layer, in this order in the direction perpendicular to the surface. In the in-plane direction, the current collecting foil extends outward relative to the positive electrode layer and the negative electrode layer. A sealing material is joined to the current collecting foil at the end in the in-plane direction, thereby sealing the gap between adjacent current collecting foils in the direction perpendicular to the surface. (1) For a laser having a wavelength of 400 to 532 nm, the current collecting foil has an absorption rate of 50% or more, and the sealing material has an absorption rate of 10% or less. (2) Alternatively, the current collecting foil has an absorptance of 50% or more and the sealing material has an absorptance of 10% or less for a laser having a wavelength of 930 to 1064 nm.

[0008] The bipolar battery of the present disclosure can be easily disassembled using a laser. The laser has a wavelength of 400 to 532 nm or 930 to 1064 nm. The sealing material exhibits an absorption rate of 10% or less for the laser. The laser can pass through the sealing material. Therefore, the laser can be irradiated onto the bonding interface between the current collecting foil and the sealing material through the sealing material. The current collecting foil exhibits an absorption rate of 50% or more for the laser. The laser can be absorbed by the current collecting foil. The heat input from the laser can cause the current collecting foil to heat up. The heat generated by the current collecting foil melts the surface of the sealing material, allowing the sealing material to peel off from the current collecting foil. Separation of the sealing material can facilitate smooth disassembly of the bipolar battery.

[0009] 2. The bipolar battery described in "1" above may include, for example, the following configuration: The current collector foil includes, in the direction perpendicular to the surface, a first metal foil, an adhesive layer, and a second metal foil, in this order. The adhesive layer bonds the first metal foil and the second metal foil. The first metal foil includes aluminum (Al). The second metal foil includes copper (Cu). The sealing material includes a polyolefin resin.

[0010] 3. The bipolar battery according to the above item "1" or "2" may include, for example, the following configuration: The current collecting foil further includes a carbon coating layer, and at least a portion of the carbon coating layer is disposed at the bonding interface between the current collecting foil and the sealing material.

[0011] For example, aluminum foil tends to have a low laser absorption rate due to its high laser reflectivity. The carbon coating layer may be black. For example, forming a carbon coating layer on the surface of a metal foil is expected to improve the absorption rate.

[0012] 4. One aspect of the present disclosure is a method for producing recycled materials. The method for producing recycled materials includes the following steps (a) to (c): (a) Prepare a bipolar battery described in any one of the above items "1" to "3". (b) A laser is irradiated through the seal material onto the bonding interface between the current collecting foil and the seal material, thereby separating the seal material from the bipolar electrode. (c) Recover various materials from the bipolar electrode. The laser has a wavelength of 400 to 532 nm, or alternatively has a wavelength of 930 to 1064 nm.

[0013] 5. The method for producing recycled materials described in "4" above may include, for example, the following configuration: (b) above includes applying a tensile force to the current collector foil in an in-plane direction.

[0014] It is expected that the combination of laser irradiation and tensile force will promote the separation of the sealing material and the bipolar electrode (current collecting foil).

[0015] Hereinafter, one embodiment of the present disclosure (hereinafter, may be abbreviated as "the present embodiment") will be described. However, this embodiment does not limit the technical scope of the present disclosure. This embodiment is illustrative in all respects. This embodiment is non-restrictive. The technical scope of the present disclosure encompasses all modifications within the meaning and scope equivalent to the claims. For example, it is also intended from the beginning that any configuration may be extracted from this embodiment and arbitrarily combined. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic perspective view of a bipolar battery according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Figure 3] 2 is a schematic cross-sectional view showing a bipolar electrode and a sealing material in the present embodiment. FIG. [Figure 4] 1 is a graph showing the relationship between laser wavelength and absorptance. [Figure 5] 1 is a schematic flowchart of a method for producing recycled materials in the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] -Terms and phrases- Geometric terms should not be interpreted in a strict sense. Examples of geometric terms include "parallel," "perpendicular," and the like. For example, directions, angles, distances, and the like may be displaced relative to one another as long as substantially the same or similar functions are obtained. Geometric terms may include, for example, tolerances, errors, and the like in design, work, manufacturing, and the like. The dimensional relationships in each figure may not match the actual dimensional relationships. The dimensional relationships in each figure may be changed to aid the reader's understanding. For example, length, width, thickness, and the like may be changed. Some components may be omitted.

[0018] The "perpendicular to the surface" refers to the normal direction to the surface of a sheet-like member (e.g., foil, electrode, etc.). The "in-plane direction" refers to any direction perpendicular to the perpendicular to the surface. In the drawings of this embodiment, the Z-axis direction corresponds to the perpendicular to the surface. The X-axis direction and the Y-axis direction are examples of in-plane directions.

[0019] The "absorption rate" is calculated by the following formula: A=100%-RT A: Laser absorption rate, R: Laser reflectance, T: Laser transmittance The transmittance and reflectance of the sealing material (resin) can be measured, for example, in accordance with "JIS K7375." For example, in the case of metal foil, it can be considered that "T=0." The reflectance of the metal foil can be measured using a spectrophotometer. For example, the reflectance of the metal foil may be measured using a spectrophotometer with the product name "V-570" (manufactured by JASCO Corporation).

[0020] -Bipolar battery- FIG. 1 is a schematic perspective view of a bipolar battery according to this embodiment. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. The bipolar battery 100 includes an exterior body 90 and a power generating element 50. The exterior body 90 houses the power generating element 50. The exterior body 90 may include, for example, a first current collecting plate 91, a first laminate film 92, a second laminate film 93, and a second current collecting plate 94. The first laminate film 92 and the second laminate film 93 are bonded to each other at their in-plane end portions. At the bond between the first laminate film 92 and the second laminate film 93, a sealant (not shown) may be interposed between the first laminate film 92 and the second laminate film 93.

[0021] The first current collector plate 91 and the second current collector plate 94 are joined to the power generating element 50 at their ends in the stacking direction (Z-axis direction). A first laminate film 92 is joined to the first current collector plate 91. A second laminate film 93 is joined to the second current collector plate 94. A sealant (not shown) may be interposed between the current collector plate and the laminate film at the joint between the current collector plate and the laminate film.

[0022] The power generating element 50 includes a plurality of bipolar electrodes 10. The plurality of bipolar electrodes 10 are stacked in the direction perpendicular to the plane (Z-axis direction). Each of the plurality of bipolar electrodes 10 includes a positive electrode layer 11, a current collecting foil 13, and a negative electrode layer 12, in this order, in the direction perpendicular to the plane. In the in-plane direction (e.g., the X-axis direction), the current collecting foil 13 extends outward relative to the positive electrode layer 11 and the negative electrode layer 12. For example, the current collecting foil 13 may extend outward relative to the positive electrode layer 11 and the negative electrode layer 12 over the entire periphery in the in-plane direction.

[0023] The power generating element 50 includes a sealing material 30. The sealing material 30 is joined to the current collecting foil 13 at the end in the in-plane direction. The sealing material 30 may be, for example, heat-welded to the current collecting foil 13. For example, the sealing material 30 may be disposed around the entire periphery in the in-plane direction. The sealing material 30 seals between adjacent current collecting foils 13 in the direction perpendicular to the plane. The sealing material 30 seals between the current collecting foils 13, thereby dividing them into cells. A cell is the smallest unit of the power generating element 50. Because the bipolar battery 100 includes multiple cells, it may also be called a "bipolar module."

[0024] -Current collecting foil and sealing material- 3 is a schematic cross-sectional view showing a bipolar electrode and a sealing material in this embodiment. The current collecting foil 13 and the sealing material 30 are configured to be separated by laser irradiation. For example, the current collecting foil 13 may be configured so that at least a portion of the sealing material 30 is separated by laser irradiation. For example, the current collecting foil 13 may be configured so that the sealing material 30 on one side is separated by laser irradiation. For example, the current collecting foil 13 may be configured so that the sealing material 30 on both sides is separated by laser irradiation.

[0025] The laser may have a wavelength of, for example, 400 to 532 nm. The laser may include, for example, at least one laser selected from the group consisting of a blue laser and a green laser. Alternatively, the laser may have a wavelength of, for example, 930 to 1064 nm. The laser may include, for example, the fundamental wave of a YAG laser.

[0026] The sealing material 30 transmits the laser. The sealing material 30 has an absorptance of 10% or less. An absorptance of 10% or less allows a laser with sufficient power to reach the current collecting foil 13. The absorptance of the sealing material 30 may be, for example, 9% or less, 8% or less, 7% or less, 6% or less, or 5% or less. The absorptance of the sealing material 30 may be, for example, 0% or more, 1% or more, 2% or more, 3% or more, 4% or more, or 5% or more.

[0027] The absorbency of the sealing material 30 can be adjusted by, for example, the material, thickness, density, crystallinity, etc. The sealing material 30 may contain, for example, at least one selected from the group consisting of polyolefin resin, polyamide resin, acrylic resin, and fluororesin. The sealing material 30 may contain, for example, at least one selected from the group consisting of polyethylene (PE) and polypropylene (PP). The thickness of the sealing material 30 may be, for example, 5 mm or less, 3 mm or less, 1 mm or less, 0.8 mm or less, 0.6 mm or less, 0.4 mm or less, or 0.2 mm or less. The thickness of the sealing material 30 may be, for example, 0.01 mm or more, 0.05 mm or more, 0.1 mm or more, or 0.2 mm or more.

[0028] The current collecting foil 13 absorbs the laser. The current collecting foil 13 has an absorptance of 50% or more. An absorptance of 50% or more allows the current collecting foil 13 to generate sufficient heat. The heat generated by the current collecting foil 13 may cause the sealing material 30 to peel off from the current collecting foil 13. The absorptance of the current collecting foil 13 may be, for example, 55% or more, 60% or more, 65% or more, or 70% or more. The absorptance of the current collecting foil 13 may be, for example, 100% or less, 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, or 70% or less.

[0029] The laser absorptance may be different on both sides of current collecting foil 13. When the absorptance is different on both sides, the higher value is regarded as the absorptance of current collecting foil 13. For example, as described below, when current collecting foil 13 is formed by bonding two sheets of metal foil together, the absorptance may be different on both sides.

[0030] As shown in FIG. 3, the current collector foil 13 may include, for example, a first metal foil 13a, an adhesive layer 13c, and a second metal foil 13b in this order in the perpendicular direction. The first metal foil 13a is a positive electrode current collector foil. The first metal foil 13a may include, for example, Al. The first metal foil 13a may include, for example, Al foil, Al alloy foil, titanium foil, stainless steel foil, etc. The thickness of the first metal foil 13a may be, for example, 5 μm or more, 10 μm or more, 25 μm or more, 50 μm or more, or 75 μm or more. The thickness of the first metal foil 13a may be, for example, 100 μm or less, 75 μm or less, or 50 μm or less.

[0031] The adhesive layer 13c bonds the first metal foil 13a and the second metal foil 13b together. The adhesive layer 13c may include, for example, a conductive adhesive. The thickness of the adhesive layer 13c may be, for example, 0.5 μm or more, 1 μm or more, 2 μm or more, or 3 μm or more. The thickness of the adhesive layer 13c may be, for example, 10 μm or less, 5 μm or less, or 3 μm or less.

[0032] The second metal foil 13b is a negative electrode current collector foil. The second metal foil 13b may contain, for example, Cu. The second metal foil 13b may contain, for example, Cu foil, Cu alloy foil, Ni foil, etc. The second metal foil 13b may be thinner than the first metal foil 13a. The thickness of the second metal foil 13b may be, for example, 2 μm or more, 4 μm or more, 6 μm or more, 8 μm or more, or 10 μm or more. The thickness of the second metal foil 13b may be, for example, 20 μm or less, 15 μm or less, 12 μm or less, 10 μm or less, or 8 μm or less.

[0033] For example, the absorptivity of the current collector foil 13 may be adjusted by roughening the surface of at least one of the first metal foil 13a and the second metal foil 13b. Roughening the surface is expected to increase the absorptivity. For example, the absorptivity of the current collector foil 13 may be adjusted by applying a black pigment to the surface of at least one of the first metal foil 13a and the second metal foil 13b. For example, molybdenum disulfide, iron oxide, or the like may be applied. Applying the black pigment is also expected to increase the absorptivity.

[0034] For example, the current collecting foil 13 may include a carbon coating layer 13d. At least a portion of the carbon coating layer 13d may be disposed at the bonding interface between the current collecting foil 13 and the sealing material 30. For example, the carbon coating layer 13d may cover the entire surface of the current collecting foil 13. The carbon coating layer 13d may be formed on only one side of the current collecting foil 13. The carbon coating layer 13d may be formed on both sides of the current collecting foil 13. The carbon coating layer 13d may be formed only at the bonding interface between the current collecting foil 13 and the sealing material 30.

[0035] FIG. 4 is a graph showing the relationship between laser wavelength and absorptance. Cu foil can exhibit an absorptance of 50% or more for lasers with wavelengths from 400 to 532 nm. However, Cu foil can exhibit an absorptance of less than 30% for lasers with wavelengths from 930 to 1064 nm. Al foil can exhibit an absorptance of less than 30% for lasers with wavelengths from 400 to 1064 nm. Forming a carbon coating layer 13d on the surface of Cu foil and Al foil tends to significantly improve absorptance. Furthermore, absorptance tends to be stable over a wide wavelength range. Cu foil and Al foil with a carbon coating layer 13d can exhibit an absorptance of 50% or more for lasers with wavelengths from 400 to 1064 nm. By providing a carbon coating layer 13d, absorptance can be improved to, for example, 60% or more, 70% or more, 80% or more, or 90% or more.

[0036] The carbon coating layer 13d includes a carbon material. The carbon material may include, for example, at least one selected from the group consisting of carbon black, graphite, carbon fiber, carbon nanotubes, and graphene flakes. The carbon coating layer 13d may further include, for example, a binder in addition to the carbon material. The binder may include, for example, polyvinylidene fluoride (PVDF). For example, the carbon coating layer 13d may include a mass fraction of 10 to 90% carbon material, with the remainder being a binder. For example, the absorbency of the current collecting foil 13 may be adjusted by the basis weight of the carbon coating layer 13d. The basis weight of the carbon coating layer 13d may be, for example, 0.01 g / m 2 More than 0.1g / m 2 More than 0.2g / m 2 More than 0.3g / m 2 More than 0.4g / m 2 More than 0.5g / m 2 More than 0.6g / m 2 More than 0.7g / m 2 More than 0.8g / m 2 More than 0.9g / m 2 or more, or 1.0 g / m 2 The weight of the carbon coating layer 13d may be, for example, 2.0 g / m 2 Below 1.5g / m 2 Below 1.2g / m 2 or less than 1.0 g / m 2 The thickness of the carbon coating layer 13d may be, for example, 0.05 μm or more, 0.01 μm or more, 0.1 μm or more, or 0.25 μm or more. The thickness of the carbon coating layer 13d may be, for example, 1 μm or less, 0.75 μm or less, or 0.5 μm or less. The carbon coating layer 13d may be formed by, for example, gravure coating.

[0037] -others- The positive electrode layer 11 is attached to one surface (first metal foil 13a) of the current collector foil 13. A carbon coating layer 13d may be interposed between the positive electrode layer 11 and the first metal foil 13a. The positive electrode layer 11 includes a positive electrode active material. The positive electrode active material may include, for example, a lithium nickel composite oxide, an olivine-type phosphate compound, or the like. The positive electrode layer 11 may further include a conductive material and a binder. The conductive material may include, for example, carbon black, or the like. The binder may include, for example, PVDF, or the like.

[0038] The negative electrode layer 12 is attached to one surface (second metal foil 13b) of the current collector foil 13. A carbon coating layer 13d may be interposed between the negative electrode layer 12 and the second metal foil 13b. The negative electrode layer 12 may have, for example, a larger area than the positive electrode layer 11. The negative electrode layer 12 includes a negative electrode active material. The negative electrode active material may include, for example, graphite, silicon, silicon oxide, a silicon-carbon composite material (Si / C material), etc. The negative electrode layer 12 may also further include a conductive material and a binder. The conductive material is the same as that of the positive electrode layer 11. The binder may include, for example, carboxymethyl cellulose, styrene-butadiene rubber, etc.

[0039] The separator 20 is interposed between the bipolar electrodes 10. The separator 20 electrically separates the positive electrode layer 11 from the negative electrode layer 12. The separator 20 may include, for example, a porous resin membrane.

[0040] The electrolyte (not shown) is a liquid electrolyte. The electrolyte is filled in each cell. The electrolyte may include, for example, a lithium salt and a solvent.

[0041] In some embodiments, the bipolar battery 100 may be an all-solid-state battery. The all-solid-state battery includes a solid electrolyte instead of a separator and an electrolytic solution. The solid electrolyte may include, for example, a sulfide solid electrolyte (such as lithium phosphorus sulfide).

[0042] As shown in FIG. 2, the power generating element 50 may further include a terminal unit in addition to the bipolar electrode 10. The terminal unit is disposed at an end in the stacking direction (the direction perpendicular to the surface). The terminal unit may have, for example, a monopolar structure. The terminal unit may be composed of, for example, a positive electrode layer 11 and a current collector foil 13 (first metal foil 13a). The terminal unit may be composed of, for example, a negative electrode layer 12 and a current collector foil 13 (second metal foil 13b).

[0043] -Method of manufacturing recycled materials- Figure 5 is a schematic flowchart of the method for producing recycled materials in this embodiment. Hereinafter, the "method for producing recycled materials in this embodiment" may be abbreviated as "this method." This method includes "(a) preparation," "(b) separation," and "(c) recovery."

[0044] (a) Preparation This method includes preparing a bipolar battery 100. Details of the bipolar battery 100 are as described above. For example, a used battery that has progressed in deterioration may be prepared. For example, a defective battery discarded from a manufacturing process may be prepared.

[0045] (b) Separation This method includes irradiating a laser through the sealing material 30 to the bonding interface between the current collecting foil 13 and the sealing material 30, thereby separating the sealing material 30 and the bipolar electrode 10. For example, first, a cutting process or the like may be performed on the exterior body 90 so that at least a portion of the sealing material 30 is exposed. The exposed sealing material 30 is irradiated with a laser.

[0046] A laser having a wavelength of 400 to 532 nm or a laser having a wavelength of 930 to 1064 nm is selected according to the absorption rates of the sealing material 30 and the current collecting foil 13. The laser may be continuous wave or pulsed. The laser output may be, for example, 1000 W or more, 1100 W or more, 1200 W or more, 1300 W or more, or 1400 W or more. The laser output may be, for example, 1600 W or less, 1500 W or less, or 1400 W or less. The laser incident angle may be, for example, 10 degrees or more, 20 degrees or more, 40 degrees or more, 60 degrees or more, or 80 degrees or more. The laser incident angle may be, for example, 90 degrees or less, 85 degrees or less, or 80 degrees or less.

[0047] The heat input from the laser can generate heat in the current collecting foil 13. The heat generated by the current collecting foil 13 can melt the surface of the sealing material 30, causing the sealing material 30 to peel off from the current collecting foil 13. The sealing material 30 on one side (one surface) may peel off, or the sealing material 30 on both sides (both surfaces) may peel off.

[0048] This method may include applying a tensile force to the current collector foil 13 in an in-plane direction. For example, first, a part of the sealing material 30 may be cut in the in-plane direction so that the tip of the current collector foil 13 is exposed. The exposed part may be grasped and a tensile force may be applied to the current collector foil 13. For example, a laser may be irradiated while a tensile force is being applied. For example, a tensile force may be applied after the laser irradiation. The tensile force may be applied, for example, in a uniaxial direction or in multiple axial directions (e.g., biaxial directions).

[0049] (c) Recovery This method includes recovering various materials from the bipolar electrode 10. For example, the positive electrode composite (positive electrode layer 11), the negative electrode composite (negative electrode layer 12), the current collector foil 13 (first metal foil 13a, second metal foil 13b), etc. may be recovered.

[0050] Recycled materials can be produced from the recovered materials. For example, various battery materials may be produced. For example, the recovered positive electrode active material may be used as the recycled material as is (direct recycling). For example, a positive electrode active material may be synthesized from the recovered material (metal salt). For example, metal products may be produced by melting and refining the recovered current collecting foil. [Explanation of symbols]

[0051] 10 bipolar electrode, 11 positive electrode layer, 12 negative electrode layer, 13 current collecting foil, 13a first metal foil, 13b second metal foil, 13c adhesive layer, 13d carbon coating layer, 20 separator, 30 sealing material, 50 power generating element, 90 outer casing, 91 first current collecting plate, 92 first laminate film, 93 second laminate film, 94 second current collecting plate, 100 bipolar battery.

Claims

1. a plurality of bipolar electrodes and a sealing material; The plurality of bipolar electrodes are stacked in a direction perpendicular to the surface, each of the plurality of bipolar electrodes includes a positive electrode layer, a current collecting foil, and a negative electrode layer in this order in the direction perpendicular to the surface; the current collecting foil extends outward relative to the positive electrode layer and the negative electrode layer in an in-plane direction, the sealing material is joined to the current collecting foil at the end portion in the in-plane direction, thereby sealing the spaces between the current collecting foils adjacent to each other in the perpendicular-to-plane direction; For lasers with wavelengths between 400 and 532 nm: The current collecting foil has an absorbency of 50% or more, and The sealing material has an absorption rate of 10% or less, or For lasers with wavelengths between 930 and 1064 nm, The current collecting foil has an absorbency of 50% or more, and The sealing material has an absorption rate of 10% or less. Bipolar battery.

2. the current collecting foil includes a first metal foil, an adhesive layer, and a second metal foil in this order in the plane perpendicular direction; the adhesive layer bonds the first metal foil and the second metal foil together, the first metal foil includes aluminum; The second metal foil includes copper, and The sealing material contains a polyolefin resin.

10. The bipolar battery of claim 1.

3. The current collecting foil further includes a carbon coating layer, and At least a portion of the carbon coating layer is disposed at the bonding interface between the current collecting foil and the sealing material.

10. The bipolar battery of claim 1.

4. (a) providing a bipolar battery according to any one of claims 1 to 3; (b) separating the sealing material from the bipolar electrode by irradiating a laser through the sealing material to a bonding interface between the current collecting foil and the sealing material; and (c) recovering various materials from the bipolar electrode; Including, The laser has a wavelength of 400 to 532 nm, or has a wavelength of 930 to 1064 nm. How recycled materials are produced.

5. (b) includes applying a tensile force to the current collecting foil in the in-plane direction. A method for producing the recycled material according to claim 4.

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