Manufacturing method of electrode body

Abstract

To provide a manufacturing method of an electrode body capable of manufacturing the electrode body with high energy efficiency.SOLUTION: A manufacturing method of an electrode body includes a drying step of drying a coated sheet 10, which is obtained by coating a collector sheet 1 having a length direction in a first direction with an electrode material, using a laser device 20, which radiates laser beams, and a pair of hot-blast devices 30, which blows a hot wind, while transferring the coated sheet in the first direction. The laser device comprises a laser head, which radiates the laser beams, and a reflector 22 including a skirt part which re-reflects the laser beams reflected from the coated sheet to the coated sheet. In the drying step, a first hot-blast device 30A which is provided at an upstream side of the laser device and a second hot-blast device 30B which is provided at a downstream side of the laser device are used as the pair of hot-blast devices, and the first hot-blast device and the second hot-blast device blow the hot wind to the side of the laser device in the first direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing an electrode assembly. [Background technology]

[0002] A known technique for manufacturing an electrode body (electrode sheet) used in the manufacture of batteries such as lithium-ion secondary batteries is to apply an electrode material to a conveyed current collector sheet to form a coated portion, and then dry the coated portion to obtain an electrode layer.

[0003] For example, Patent Document 1 discloses a method for manufacturing an electrode, which includes a coating step in which an active material mixture is applied to a long metal foil being transported to form a coated portion of the active material mixture, a first irradiation step that is performed prior to the coating step in which a laser is irradiated to an irradiation position on the long metal foil that is located upstream in the transport direction of the long metal foil from both ends of the mixture application location along the short side of the long metal foil, and a second irradiation step that is performed after the first irradiation step in which a laser is irradiated to both edges in the short side of the coated portion formed by the coating step. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-029256 A Summary of the Invention [Problem to be solved by the invention]

[0005] From the perspective of reducing CO2 emissions and saving electricity, there is a demand for manufacturing electrode assemblies while improving energy efficiency.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and has a main object to provide a manufacturing method for an electrode assembly that can manufacture an electrode assembly with energy efficiency. [Means for solving the problem]

[0007] [1] A method for manufacturing an electrode body, comprising: a preparation step of preparing a coated sheet having a coated portion coated with an electrode material on a first surface of a current collecting sheet having a longitudinal direction in a first direction; and a drying step of drying the coated sheet using a laser device that irradiates laser light onto the coated sheet and a pair of hot air devices that blow hot air onto the coated sheet while transporting the coated sheet in the first direction, wherein the laser device has a laser head that irradiates the laser light, and a reflector having a skirt portion that re-reflects the laser light reflected from the coated sheet back onto the coated sheet, and in the drying step, the pair of hot air devices include a first hot air device provided upstream of the laser device and a second hot air device provided downstream of the laser device, and the first hot air device and the second hot air device each blow the hot air toward the laser device in the first direction. Effect of the Invention

[0008] The present disclosure provides the effect of enabling the electrode assembly to be manufactured with energy efficiency. [Brief description of the drawings]

[0009] [Figure 1] 1A and 1B are schematic plan views and schematic cross-sectional views illustrating a preparation step in the present disclosure. [Diagram 2] 1A and 1B are schematic cross-sectional and plan views illustrating a drying process in the present disclosure. [Diagram 3] 1 is a graph showing the reflectance of laser light in a coated portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The manufacturing method of the electrode body in the present disclosure will be described in detail below with reference to the drawings. Each of the drawings shown below is a schematic illustration, and the size and shape of each part are appropriately exaggerated to facilitate understanding. In addition, in this specification, when expressing an aspect in which another member is arranged relative to a certain member, simply writing "above" or "below" includes both a case in which another member is arranged directly above or below a certain member so as to be in contact with the certain member, and a case in which another member is arranged above or below a certain member via another member.

[0011] FIG. 1 is a schematic plan view and a schematic cross-sectional view illustrating the preparation step in the present disclosure. Specifically, FIG. 1(a) is a schematic plan view of a coated sheet prepared in the preparation step as viewed from the thickness direction, and FIG. 1(b) is a cross-sectional view taken along line AA of FIG. 1(a). Also, FIG. 2 is a schematic cross-sectional view and a schematic plan view illustrating the drying step in the present disclosure. Specifically, FIGS. 2(a) and 2(b) are schematic cross-sectional views illustrating the drying step, and FIG. 2(c) is a schematic plan view of a laser device in the drying step as viewed from the coated sheet side. As shown in FIG. 2(c), the reflector is usually arranged to surround the outer edge of the laser irradiation port 21a, so strictly speaking, the reflector is also present on the back side of the paper in FIGS. 2(a) and 2(b) (behind the laser L), but is not shown for ease of understanding. Also, in FIG. 2(b), the coated portion of the coated sheet is omitted for ease of understanding.

[0012] As shown in Fig. 1, in the manufacturing method of an electrode body according to the present disclosure, first, a coated sheet 10 having a coated portion 2 coated with an electrode material on a first surface S1 of a current collecting sheet 1 having a longitudinal direction in a first direction D1 is prepared (preparation step). Next, as shown in Figs. 2(a) and (b), while conveying the coated sheet 10 in the first direction D1, the coated sheet 10 is dried (drying step) using a laser device 20 that irradiates the coated sheet 10 with laser light and a pair of hot air devices 30 (30A and 30B) that blow hot air to the coated sheet 10. As shown in Figs. 2(a) to (c), the laser device 20 includes a laser head 21 that irradiates laser light, and a reflector 22 having a skirt portion 22a that re-reflects the laser light reflected from the coated sheet 10 back to the coated sheet 10. Also, as shown in FIG. 2(a), in the drying process, a pair of hot air devices 30 is used, which includes a first hot air device 30A provided upstream of the laser device 20 and a second hot air device 30B provided downstream of the laser device 20, and the first hot air device 30A and the second hot air device 30B each blow the hot air toward the laser device 20 in a first direction D1.

[0013] According to the present disclosure, since the laser device is equipped with a reflector having a skirt portion, the irradiated laser can be used efficiently for drying, and the laser net rate can be improved. In addition, since the pair of hot air devices each blow hot air toward the laser device side, the hot air can be retained in the space surrounded by the reflector (skirt portion), and the hot air can be used efficiently for drying. Due to these effects, the manufacturing method of the electrode body according to the present disclosure allows the electrode body to be manufactured with energy efficiency.

[0014] As shown in FIG. 3, a part of the laser light irradiated to the coated portion is reflected. Although not shown, the current collecting sheet of the coated sheet is generally made of metal, so the reflectance of the laser light irradiated to the current collecting sheet is greater than that of the coated portion. The reflected laser light cannot contribute to drying, and is lost as energy. In contrast, according to the present disclosure, the laser light reflected from the coated portion and the current collecting sheet is reflected back to the coated sheet (coated portion), so that the laser light irradiated from the laser device can be efficiently used for drying.

[0015] 1. Preparation process As shown in Figures 1(a) and (b), the preparation process in the present disclosure is a process of preparing a coated sheet 10 having a coated portion 2 coated with an electrode material on a first surface S1 of a collector sheet having a longitudinal direction in a first direction D1.

[0016] The current collecting sheet has a longitudinal direction in a first direction. The current collecting sheet has a first surface S1 which is one surface in the thickness direction, and a second surface S2 which is the reverse surface of the first surface S1. The current collecting sheet is not particularly limited as long as it is made of a material that can be used as a current collector such as a negative electrode current collector, a positive electrode current collector, or a bipolar current collector.

[0017] The electrode material may be a negative electrode material (a material for a negative electrode active material layer). The negative electrode material includes, for example, a negative electrode active material, a conductive material, a binder, and a solvent. The electrode material may be a positive electrode material (a material for a positive electrode active material layer). The positive electrode material includes, for example, a positive electrode active material, a conductive material, a binder, and a solvent. These materials are not particularly limited, and known materials are used.

[0018] The coated portion may be disposed only on the first surface of the current collecting sheet, or may be disposed on both the first surface and the second surface of the current collecting sheet. The thickness of the coated portion is not particularly limited.

[0019] The method for preparing the coated sheet is not particularly limited, but for example, the coated sheet can be prepared by conveying the current collecting sheet in a first direction with a conveyor while applying the electrode material to at least the first surface of the current collecting sheet with a coater to form a coated portion. In this case, the electrode material may be applied continuously or intermittently.

[0020] 2.Drying process 2(a), the drying step in the present disclosure is a step of drying the coated sheet using a laser device 20 that irradiates coated sheet 10 with laser light and a pair of hot air devices 30 (30A, 30B) that blow hot air onto coated sheet 10 while transporting coated sheet 10 in a first direction D1. Although not specifically shown, the drying step is typically performed in a drying furnace.

[0021] 2(a) to 2(c), the laser device 20 includes a laser head 21 that irradiates laser light, and a reflector 22 having a skirt portion 22a that reflects the laser light reflected from the coated sheet 10 back to the coated sheet 10. As shown in FIG. 2(c), the laser head 21 has a laser irradiation port 21a, and the reflector 22 is disposed outside the outer edge of the laser irradiation port so as to surround the entire outer edge of the laser head.

[0022] Here, as shown in FIG. 2(a), the skirt portion 22a refers to a portion of the reflector 22 that is inclined so as to become closer to the current collecting sheet in a direction away from the laser head 21 when the laser device 20 is viewed in cross section. As shown in FIG. 2(b), the reflector 22 may have only the skirt portion 22a, and the skirt portion 22a may be connected to the laser head 21. Although not shown in particular, the reflector may have a body portion that connects the skirt portion and the laser head. By having such a skirt portion, it is possible to reduce excess space in drying equipment such as a drying oven.

[0023] Furthermore, as shown in Fig. 2(b), when the laser incidence angle at the outermost circumference is θ1 and the reflector angle (angle of the skirt portion) is θ2, it is preferable that θ1<θ2. θ2 may be, for example, θ1+5 degrees or more, θ1+10 degrees or more, or θ1+15 degrees or more. On the other hand, θ2 is, for example, θ1+60 degrees or less. By setting the relationship between θ1 and θ2 as described above, the reflector can reflect the laser more efficiently.

[0024] The reflector (skirt portion) preferably has a high laser reflectance. The laser reflectance is, for example, 50% or more, 70% or more, or may be 90% or more. On the other hand, the laser reflectance may be 100% or less than 100%.

[0025] The material of the reflector (material of the skirt portion) is preferably a metal such as Al, Ag, Cu, or SUS, for example. This is because it is possible to increase the laser reflectance. In addition, it is preferable that the laser light reflecting surface of the skirt portion is mirror-finished, which can further increase the laser reflectance.

[0026] The laser head in the laser device is not particularly limited and may be a conventionally known member.

[0027] The wavelength of the laser light is not particularly limited, but is, for example, 900 nm or more and 1060 nm or less. The energy density of the laser light and the irradiation time of the laser light can be appropriately adjusted depending on the situation such as the size of the coated part. The energy density of the laser light is, for example, 0.1 W / cm 2 More than 1.0W / cm 2 The irradiation time of the laser light is, for example, not less than 10 seconds and not more than 3 minutes.

[0028] 2(a), a pair of hot air devices 30 includes a first hot air device 30A provided upstream of the laser device 20 and a second hot air device 30B provided downstream of the laser device 20. The first hot air device 30A and the second hot air device 30B each blow hot air toward the laser device 20 in a first direction D1. This allows the hot air to remain inside the skirt portion, allowing the electrode sheet to be dried more efficiently.

[0029] The hot air device is not particularly limited, and a conventionally known device can be used. The temperature of the hot air is not particularly limited, and is, for example, 100° C. or more and 120° C. or less. The speed of the hot air is not particularly limited, and is, for example, 5 m / s or more and 30 m / s or less.

[0030] 3. Electrode body The electrode assembly manufactured in the present disclosure has a current collector sheet and an electrode layer formed on a first surface of the current collector sheet. A plurality of electrode layers may be formed intermittently on the current collector sheet. In the electrode assembly, the electrode layers may be formed on the first surface of the current collector sheet and on a second surface opposite to the first surface.

[0031] The electrode body is used in the manufacture of a battery and may be a positive electrode side member (electrode sheet) or a negative electrode side member (electrode sheet). That is, the current collector sheet and the electrode layer may be a positive electrode current collector and a positive electrode active material layer, or a negative electrode current collector and a negative electrode active material layer. When the electrode body in the present disclosure is a positive electrode side electrode sheet, it is combined with a negative electrode side electrode sheet and a separator to form a unit battery. Similarly, when the electrode body in the present disclosure is a negative electrode side electrode sheet, it is combined with a positive electrode side electrode sheet and a separator to form a unit battery.

[0032] The type of battery in which the electrode body is used is not particularly limited, and may be, for example, a lithium ion secondary battery. Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline automobiles, and diesel automobiles. In particular, the battery is preferably used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery may also be used as a power source for moving objects other than vehicles (for example, railways, ships, and aircraft), and may also be used as a power source for electrical appliances such as information processing devices.

[0033] The present disclosure is not limited to the above-described embodiment. The above-described embodiment is merely an example, and any configuration that is substantially the same as the technical idea described in the claims of the present disclosure and that exhibits similar effects is included in the technical scope of the present disclosure. [Explanation of symbols]

[0034] 1...Current collecting sheet 2 … Coating section 10...Coated sheet 20...Laser device 21 ... Laser head 21a …Laser irradiation port 22...reflector 22a … Skirt section 30…Hot air device 30A…1st hot air device 30B…Second hot air device

Claims

[Claim 1] a preparation step of preparing a coated sheet having a coated portion coated with an electrode material on a first surface of a current collecting sheet having a longitudinal direction in a first direction; a drying step of drying the coated sheet using a laser device that irradiates the coated sheet with laser light and a pair of hot air devices that blow hot air onto the coated sheet while transporting the coated sheet in the first direction, The laser device includes a laser head that irradiates the laser light, and a reflector having a skirt portion that re-reflects the laser light reflected from the coated sheet back to the coated sheet, In the drying step, As the pair of hot air devices, a first hot air device provided upstream of the laser device and a second hot air device provided downstream of the laser device are used, and A method for manufacturing an electrode body, wherein the first hot air device and the second hot air device each blow the hot air toward the laser device in the first direction.

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