Method for manufacturing electrode body

Abstract

The present invention addresses the problem of providing a technique for manufacturing an electrode body having a free shape. Provided is a method for manufacturing an electrode body, the method comprising: a step in which a long electrode composite sheet is manufactured by molding a mixture, which is obtained by mixing at least a fibrillating binder with active material particles, into a sheet shape by calendering; and cutting an electrode composite material sheet having a predetermined contour shape from the long electrode composite material sheet.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a method for manufacturing an electrode. Background Technology

[0002] Patent Document 1 discloses a method for manufacturing an electrode body. This method includes a step of coating a solution of an electrode composite material containing active material particles onto a current collector. In this step, two or more dies with different coating areas are used. These two or more dies, by operating at different times, coat the electrode composite material solution onto a non-rectangular area on the current collector. Thus, a non-rectangular electrode body can be manufactured.

[0003] Patent Document 1: International Publication No. 2018 / 180019 Summary of the Invention

[0004] In the above manufacturing method, the shape of the solution for coating the electrode composite material is limited to a combination of rectangular shapes. That is, even if a non-rectangular electrode can be manufactured, its shape is limited to a combination of rectangular shapes. For example, it is preferable to be able to freely design the shape of the battery according to the space where the battery is arranged; for this purpose, technology capable of manufacturing freely shaped electrode bodies is needed.

[0005] In view of the above-mentioned circumstances, this specification provides a technique for manufacturing free-form electrode bodies.

[0006] The technology disclosed in this specification is embodied in a method for manufacturing an electrode body. In this first embodiment, the manufacturing method includes the following steps: forming a mixture of active material particles mixed with at least a fibrillable binder into a sheet by calendering, thereby producing an elongated electrode composite sheet; and cutting an electrode composite sheet having a predetermined contour shape from the elongated electrode composite sheet.

[0007] In the above manufacturing method, firstly, an elongated electrode composite material sheet is produced from the mixture. Then, electrode composite material sheets with a predetermined contour shape are cut from the elongated electrode composite material sheet. Based on this structure, it is possible to manufacture electrode bodies with free shapes.

[0008] In the second embodiment, the manufacturing method further includes a step of attaching an electrode composite material sheet having a defined contour shape to a current collector. According to this structure, an electrode body having an electrode composite material sheet on the current collector can be manufactured in a free-form shape.

[0009] In the third approach, the cutting process may include irradiating a long electrode composite sheet with a laser along a predetermined contour shape, as in the first or second approach. Since the laser irradiation position can be changed relatively easily, a free-form electrode body can be manufactured relatively easily according to the structure described above.

[0010] In the fourth embodiment, in any of the first to third embodiments, the manufacturing method may further include a step of attaching a long-sized electrode composite sheet to a transparent film. In this case, the long-sized electrode composite sheet on the film can be irradiated with laser during the laser irradiation step. For example, when irradiating a long-sized electrode composite sheet on a current collector with laser, the long-sized electrode composite sheet will be cut off, and on the other hand, the current collector may deteriorate. In this regard, the laser will penetrate the film. Therefore, if the long-sized electrode composite sheet on the film is irradiated with laser, only the long-sized electrode composite sheet will be cut off. Since the film will not burn due to the laser, contamination of the electrode composite sheet caused by burning of the film can be avoided. Subsequently, by attaching the electrode composite sheet cut into a predetermined contour shape to the current collector, a high-quality electrode body can be manufactured.

[0011] In the fifth embodiment, any of the first to fourth embodiments, the remaining portion of the long-sized electrode composite sheet after the cutting process can be reused in the subsequent manufacturing of other electrode bodies, specifically in the process of producing the long-sized electrode composite sheet. This structure reduces the amount of waste during manufacturing. Attached Figure Description

[0012] Figure 1 This is a diagram schematically illustrating the structure of the electrode body 10 in an embodiment.

[0013] Figure 2 This is a flowchart illustrating one embodiment of a method for manufacturing electrode 10.

[0014] Figure 3 This diagram illustrates the process of producing a long-sized electrode composite sheet 22 by calendering the mixture 20 into a sheet shape using a calendering apparatus 100.

[0015] Figure 4 This is a diagram illustrating the process of cutting an electrode composite sheet 14 with a specified contour shape from a long electrode composite sheet 22 using a laser device 106.

[0016] Figure 5 This is a diagram illustrating the process of using a stripping device 108 to recover the remaining portion 26 of the long-sized electrode composite sheet that remains after the cutting process.

[0017] Figure 6 This is a diagram illustrating the process of attaching an electrode composite material sheet 14 with a specified contour shape to a current collector 12 using a transfer device 112.

[0018] Figure 7 This is a modified example of the process of cutting an electrode composite sheet 14 with a specified contour shape from a long electrode composite sheet 22. Detailed Implementation

[0019] The electrode body 10 will be described with reference to the accompanying drawings. The electrode body 10 is used, for example, as the negative electrode of a lithium-ion secondary battery. However, the electrode body 10 is not limited to the negative electrode of a lithium-ion secondary battery, and can also be used as the positive electrode of a lithium-ion secondary battery. Furthermore, in this technology, the electrode body 10 is not limited to the electrode of a lithium-ion secondary battery, and can also be used as the electrode of any type of secondary battery or an electrode of an all-solid-state battery.

[0020] like Figure 1 As shown, the electrode body 10 includes a current collector 12 and an electrode composite sheet 14. The current collector 12 is a conductive sheet. The current collector 12 is, for example, an aluminum foil or a copper foil. The thickness of the current collector 12 is, for example, 5 μm or more and 50 μm or less. The electrode composite sheet 14 is disposed on the current collector 12. In this embodiment, the electrode composite sheet 14 is a self-supporting sheet. A self-supporting sheet, as used here, means a sheet that can maintain its sheet shape on its own without the need for a support such as the current collector 12. Therefore, the electrode body 10 does not necessarily need to include a current collector 12. That is, as another embodiment, the electrode composite sheet 14 can constitute the electrode body 10 alone. The thickness of the electrode composite sheet 14 is, for example, 10 μm or more and 500 μm or less.

[0021] The electrode composite sheet 14 comprises active material particles 16 and an adhesive 18 that bonds the active material particles 16 together. At least a portion of the adhesive 18 is fibrillated. As described later, the adhesive 18 is made of a fibrillable material such as polytetrafluoroethylene (PTFE). Alternatively, a portion of the adhesive 18 may be made of a non-fibrillable material such as polyvinylidene fluoride (PVdF). Furthermore, the electrode composite sheet 14 may further contain conductive additives, etc.

[0022] The active material particles 16 include negative electrode active material particles. Examples of negative electrode active material particles include, for example, carbon materials such as graphite, hard carbon, and soft carbon; materials that form alloys with lithium, such as silicon (Si); and these lithium alloys (e.g., Li). XM, where M is C, Si, Sn, Sb, Al, Mg, Ti, Bi, Ge, Pb, or P, and X is a natural number. The negative electrode active material particles can be composed of a single material or multiple materials. Furthermore, when the electrode body 10 is used as the positive electrode of a lithium-ion secondary battery, the active material particles 16 may include positive electrode active material particles instead of negative electrode active material particles. Examples of positive electrode active material particles include, for instance, rock salt layered active materials such as lithium nickel composite oxides, lithium cobalt composite oxides, lithium manganese composite oxides, lithium nickel manganese composite oxides (e.g., LiNi1 / 2Mn3 / 2O4), and lithium nickel manganese cobalt composite oxides (e.g., LiNi1 / 3Mn1 / 3Co1 / 3O2), spinel-type active materials such as lithium manganese oxide, and olivine-type active materials such as lithium iron phosphate (LFP) and lithium manganese iron phosphate (LMFP).

[0023] As described above, adhesive 18 is composed of a fibrillable material. A fibrillable material is one that can be fibrillated by applying shear force. Examples of fibrillable materials include polytetrafluoroethylene (PTFE), cellulose, acrylic resin, and ultra-high molecular weight polyethylene. In this specification, materials that are fibrillable and can function as adhesives are referred to as fibrillable adhesives. Fibrillable adhesives can be composed of a single material or multiple materials.

[0024] Next, refer to Figure 2-6 An embodiment of the manufacturing method for the electrode body 10 will be described. In this embodiment, the electrode body 10 can be manufactured without the use of solvents. That is, this manufacturing method is a so-called dry process.

[0025] like Figure 2 As shown, the manufacturing method of the embodiment includes the following step (S10): A mixture 20, formed by mixing at least a fibrillable binder 18 with active material particles 16, is calendered into a sheet shape, thereby producing an elongated electrode composite sheet 22. In this step, as... Figure 3 As shown, a calendering apparatus 100 is used, for example. The calendering apparatus 100 has a pair of rollers 102, which can calender the mixture 20 passing between the pair of rollers 102. Thus, the mixture 20 is formed into a series of sheets to produce an elongated electrode composite sheet 22. Furthermore, in the aforementioned mixture 20, some or all of the adhesive 18 can be pre-fibrillated. The method of pre-fibrillating the adhesive 18 is not particularly limited. Although this is just one example, by using a mixing mill to mix the mixture 20 supplied to the calendering apparatus 100, at least a portion of the adhesive 18 can be pre-fibrillated.

[0026] like Figure 2As shown, the manufacturing method of the embodiment further includes a step (S12) of attaching an elongated electrode composite sheet 22 onto a transparent film 24. In this step, as... Figure 3 As shown, for example, the aforementioned calendering apparatus 100 is used. The calendering apparatus 100 further includes an attachment roller 104. The attachment roller 104 is arranged opposite to one of the aforementioned pair of rollers 102. An elongated electrode composite sheet 22 formed by the pair of rollers 102 is supplied between one of the pair of rollers 102 and the attachment roller 104. A transparent film 24 is supplied from the outside onto the outer peripheral surface of the attachment roller 104. Thus, the elongated electrode composite sheet 22 is attached to the film 24 as it passes between one of the pair of rollers 102 and the attachment roller 104.

[0027] like Figure 2 As shown, the manufacturing method of the embodiment further includes a step (S14) of cutting an electrode composite sheet 14 having a predetermined contour shape from an elongated electrode composite sheet 22. In this step, as... Figure 4 As shown, for example, a laser device 106 is used. The laser device 106 irradiates a long electrode composite sheet 22 on the membrane 24 with a predetermined contour shape. This cuts an electrode composite sheet 14 with a predetermined contour shape from the long electrode composite sheet 22 on the membrane 24. Here, the laser passes through the transparent membrane 24. Therefore, only the long electrode composite sheet 22 is cut by the laser, while the membrane 24 is not cut.

[0028] like Figure 2 As shown, the manufacturing method of the embodiment further includes a step (S16) of recovering the remaining portion 26 of the long-sized electrode composite sheet after the cutting step (S14). In this step, as... Figure 5 As shown, for example, a peeling device 108 is used. The peeling device 108 includes a roller 110, which can press the electrode composite sheet 14 onto the membrane 24 while peeling the remaining portion 26 of the electrode composite sheet from the membrane 24. Therefore, the remaining portion 26 of the long-sized electrode composite sheet remaining after the cutting process (S14) is recovered. The recovered remaining portion 26 of the long-sized electrode composite sheet can be reused in the process of manufacturing long-sized electrode composite sheets 22 in the subsequent manufacturing of other electrode bodies (S10). In this case, the recovered remaining portion 26 of the long-sized electrode composite sheet can be pulverized by a mixer or the like and then mixed with the mixture 20 used in this process (S10).

[0029] like Figure 2 As shown, the manufacturing method of the embodiment further includes a step (S18) of attaching an electrode composite material sheet 14 having a defined contour shape onto the current collector 12. In this step, as... Figure 6 As shown, for example, a transfer apparatus 112 is used. The transfer apparatus 112 includes a first roller 114 and a second roller 116. A film 24 holding the electrode composite sheet 14 and a sheet-like current collector 12 are supplied between the first roller 114 and the second roller 116. Thus, the electrode composite sheet 14 on the film 24 is transferred onto the current collector 12 as it passes between the first roller 114 and the second roller 116. The electrode body 10 is manufactured by cutting the current collector 12 with the electrode composite sheet 14 attached into a predetermined shape.

[0030] In the above manufacturing method, firstly, an elongated electrode composite sheet 22 is produced from the mixture 20. Then, an electrode composite sheet 14 with a predetermined contour shape is cut from the elongated electrode composite sheet 22. Based on this structure, a free-form electrode body 10 can be manufactured.

[0031] In the above embodiments, such as Figure 2 As shown, the method for manufacturing the electrode body 10 includes a step (S18) of attaching an electrode composite material sheet 14 having a predetermined contour shape to the current collector 12. According to this structure, the electrode body 10 having the electrode composite material sheet 14 on the current collector 12 can be manufactured in a free shape.

[0032] In the above embodiments, such as Figure 4 As shown, the cutting process (S14) includes irradiating a long electrode composite sheet 22 with a laser along a predetermined contour shape. Since the laser irradiation position can be changed relatively easily, the electrode body 10 with a free shape can be manufactured relatively easily according to the structure described above.

[0033] In the above embodiments, such as Figure 2 As shown, the manufacturing method of the electrode body 10 further includes a step (S12) of attaching a long-sized electrode composite sheet 22 onto a transparent film 24. In this case, during the aforementioned laser irradiation step, the long-sized electrode composite sheet 22 on the film 24 is irradiated with laser. For example, if the long-sized electrode composite sheet 22 on the current collector 12 is irradiated with laser, the long-sized electrode composite sheet 22 will be cut off, and on the other hand, the current collector 12 may deteriorate. In this regard, the laser will pass through the film 24. Therefore, if the long-sized electrode composite sheet 22 on the film 24 is irradiated with laser, only the long-sized electrode composite sheet 22 will be cut off. Since the film 24 will not burn due to the laser, contamination of the electrode composite sheet 14 caused by the burning of the film 24 can be avoided. Then, by attaching the electrode composite sheet 14 cut into a predetermined contour shape onto the current collector 12, a high-quality electrode body 10 can be manufactured.

[0034] In the above embodiment, the remaining portion 26 of the long-sized electrode composite sheet after the cutting process (S14) is reused in the process of manufacturing the long-sized electrode composite sheet 22 in the subsequent manufacturing of other electrode bodies. According to this structure, the amount of waste during manufacturing can be reduced.

[0035] In the above embodiments, the method for manufacturing the electrode body 10 includes a step (S12) of attaching an elongated electrode composite sheet 22 onto a transparent film 24. However, in other embodiments, the method for manufacturing the electrode body 10 may not include the step (S12) of attaching the elongated electrode composite sheet 22 onto the transparent film 24. In this case, in the step (S14) of cutting an electrode composite sheet 14 with a predetermined contour shape from the elongated electrode composite sheet 22, the electrode composite sheet 14 can be cut from the laser device 106 (see reference 106). Figure 4 The long electrode composite sheet 22, which is conveyed by a conveyor belt, is irradiated with a laser. In the process of attaching the electrode composite sheet 14 with a specified contour shape to the current collector 12 (S18), a conveyor robot can be used to place the electrode composite sheet 14 on the current collector 12, and then the electrode composite sheet 14 is fixed to the current collector 12 by a pair of rollers.

[0036] In the above embodiments, the step (S14) of cutting an electrode composite sheet 14 with a predetermined contour shape from a long electrode composite sheet 22 includes irradiating the long electrode composite sheet 22 with a laser along the predetermined contour shape. However, in other embodiments, the step (S14) of cutting an electrode composite sheet 14 with a predetermined contour shape from a long electrode composite sheet 22 may not include the step of irradiating the long electrode composite sheet 22 with a laser along the predetermined contour shape. Although this is one example, it is possible to omit the step of irradiating the long electrode composite sheet 22 with a laser along the predetermined contour shape. Figure 7 As shown, an electrode composite sheet 14 with a predetermined contour shape can also be cut from an elongated electrode composite sheet 22 using a rotary die-cutting machine 118. The rotary die-cutting machine 118 includes a pair of rollers 120. A protrusion 121 with a contour having approximately the same shape as the predetermined contour shape is formed on the outer peripheral surface of one of the rollers 120. When the elongated electrode composite sheet 22 passes between the pair of rollers 120, the protrusion 121 can cut an electrode composite sheet 14 with a predetermined contour shape from the elongated electrode composite sheet 22.

[0037] The above provides detailed descriptions of several specific examples, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples illustrated above. The technical elements described in this specification or drawings, individually or in combination, contribute to the technical applicability of the technology.

[0038] Symbol Explanation

[0039] 10-Electrode body, 12-Current collector, 14-Electrode composite sheet, 16-Active material particles, 18-Adhesive, 20-Mixture, 22-Long-sized electrode composite sheet, 24-Film, 26-Remaining portion, 100-Calendar device, 106-Laser device, 108-Peeling device, 112-Transfer device, 118-Rotary die cutter.

Claims

1. A method for manufacturing an electrode, characterized in that, The process includes the following steps: Long-length electrode composite sheets are produced by calendering a mixture of active material particles and a binder capable of fibrillation into a sheet shape; and Electrode composite sheets with a specified contour shape are cut from the long-sized electrode composite sheet.

2. The method for manufacturing an electrode body according to claim 1, characterized in that, The process further includes attaching an electrode composite sheet having the specified contour shape to the current collector.

3. The method for manufacturing an electrode body according to claim 1, characterized in that, The cutting process includes irradiating the long electrode composite sheet with a laser along the specified contour shape.

4. The method for manufacturing an electrode body according to claim 3, characterized in that, The process further includes attaching the elongated electrode composite sheet onto a transparent film. In the laser irradiation process, the long-dimensional electrode composite sheet on the film is irradiated with the laser.

5. The method for manufacturing an electrode body according to claim 1, characterized in that, The remaining portion of the long-sized electrode composite sheet after the cutting process is reused in the subsequent manufacturing of other electrode bodies, in the process of making the long-sized electrode composite sheet.

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