Manufacturing method of electrode sheet

Abstract

To provide a technique capable of improving manufacturing quality of an electrode sheet for batteries.SOLUTION: A method of manufacturing an electrode sheet includes: a coating step of applying an active material paste on a surface of a long metal sheet while conveying the metal sheet; and a drying step of drying the active material paste by radiating light from a plurality of light source to the active material paste applied on the surface of the metal sheet. The plurality of light sources includes at least one first light source and at least one second light source. The first light source radiates light in a range where a first portion of the metal sheet in a width direction passes, and the second light source radiates light in a range where a second portion of the metal sheet in a width direction passes. A position of a first radiation range where the first light source radiates light and a position of a second radiation range where the second light source radiates light are different from each other in a conveyance direction of the metal sheet.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a method for producing an electrode sheet for a battery.

[0002] Patent Document 1 describes a method for manufacturing an electrode sheet, in which an active material paste is applied to the surface of a metal sheet, and then both edges of the applied active material paste are irradiated with a laser to locally dry the active material paste. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-029256 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the manufacturing method of Patent Document 1, both ends of the applied active material paste are irradiated with a laser, thereby drying the active material paste locally. In contrast, it is also possible to dry the active material paste overall by irradiating the entire width of the applied active material paste with a laser (or other light). However, irradiating the entire width of the active material paste with light causes a large increase in temperature of the metal sheet. In this case, there is a risk that unintended deformation (e.g., wrinkles) will occur in the metal sheet due to the subsequent thermal shrinkage. This specification provides a technology that can improve the manufacturing quality of electrode sheets by avoiding such problems. [Means for solving the problem]

[0005] The technology disclosed in this specification is embodied in a manufacturing method for manufacturing an electrode sheet for a battery. This manufacturing method includes a coating process for coating an active material paste on a surface of a long metal sheet while conveying the metal sheet, and a drying process, which is carried out in parallel with the coating process, for drying the active material paste by irradiating the active material paste applied to the surface of the metal sheet with light from a plurality of light sources. The plurality of light sources include at least one first light source and at least one second light source. The first light source irradiates light to a range through which a first portion in the width direction of the metal sheet passes, and the second light source irradiates light to a range through which a second portion adjacent to the first portion passes in the width direction of the metal sheet. The first irradiation range into which the first light source irradiates light and the second irradiation range into which the second light source irradiates light are different in position in the conveying direction of the metal sheet.

[0006] In the above-mentioned configuration, a first portion in the width direction of the metal sheet is irradiated with light by the first light source, and a second portion in the width direction of the metal sheet is irradiated with light by the second light source. The first irradiation range to which the first light source irradiates light and the second irradiation range to which the second light source irradiates light are located at different positions in the conveying direction of the metal sheet. With this configuration, a time difference can be provided between the timing at which the first portion is irradiated with light and the timing at which the second portion is irradiated with light in the width direction of the metal sheet. Light is not irradiated simultaneously over the entire width of the applied active material paste, and the temperature rise of the metal sheet is suppressed. [Brief description of the drawings]

[0007] [Figure 1] 1 shows a schematic configuration of an electrode sheet manufacturing apparatus 10 used in the examples. [Diagram 2] FIG. 2 is a side view showing the configuration of a drying device 16. [Diagram 3] FIG. 2 is a plan view showing the configuration of a drying device 16. [Figure 4] FIG. 13 is a plan view showing the configuration of a modified example of the drying device 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In one embodiment of the present technology, the plurality of light sources may include a plurality of the first light sources and a plurality of the second light sources. In this case, the plurality of first irradiation ranges by the plurality of first light sources may be arranged along the conveying direction of the metal sheet and may be spaced apart from each other. The plurality of second irradiation ranges by the plurality of second light sources may be arranged along the conveying direction of the metal sheet and may be spaced apart from each other. According to this configuration, in both the first portion and the second portion, the active material paste applied to the metal sheet is intermittently irradiated with light as the metal sheet 2 is conveyed. This further suppresses the temperature rise of the metal sheet.

[0009] In the above-described embodiment, the first irradiation areas by the first light sources and the second irradiation areas by the second light sources may be arranged alternately one by one in the conveying direction of the metal sheet. That is, the first irradiation areas and the second irradiation areas may be arranged in a staggered manner. With this configuration, the dimension in the conveying direction required for the drying process can be shortened.

[0010] In one embodiment of the present technology, the first and second portions of the metal sheet may include an entire width of the active material paste applied to the metal sheet, i.e., the entire width of the applied active material paste may be divided into two, and each portion may be dried by a first light source or a second light source.

[0011] Alternatively, the plurality of light sources may further include a plurality of third light sources. In this case, the third light source may irradiate a third portion in the width direction of the metal sheet, in a range through which the third portion adjacent to the second portion passes from the opposite side to the first portion. The plurality of third irradiation ranges by the plurality of third light sources may be arranged along the conveying direction of the metal sheet and may be spaced apart from each other. The plurality of third irradiation ranges by the plurality of third light sources may coincide with the plurality of first irradiation ranges by the plurality of first light sources in the conveying direction of the metal sheet. The first portion, the second portion, and the third portion of the metal sheet may include the entire width of the active material paste applied to the metal sheet. That is, the entire width of the applied active material paste may be divided into three, and each portion may be dried by the first light source, the second light source, or the third light source. According to this configuration, the irradiation range of each light source may be made smaller, so that the temperature rise of the metal sheet can be further suppressed. In still another embodiment, the overall width of the applied active material paste may be divided into four or more sections, and the plurality of light sources may further include a fourth light source and a fifth light source corresponding thereto. EXAMPLES

[0012] A manufacturing method of the embodiment will be described with reference to the drawings. The manufacturing method of the embodiment is for manufacturing an electrode sheet for a battery, and is carried out using a manufacturing apparatus 10 shown in FIG. 1. The battery referred to here is not particularly limited, but may be, for example, a lithium ion battery. The electrode sheet may be an electrode sheet for a positive electrode or an electrode sheet for a negative electrode.

[0013] As shown in FIG. 1, a manufacturing apparatus 10 includes a conveying device 12, a coating device 14, and a drying device 16. The conveying device 12 conveys a long metal sheet 2 along a predetermined conveying path. The metal sheet 2 is made of, but is not limited to, copper or aluminum. The surface of the metal sheet 2 may be carbon coated. Note that the direction X in the figure indicates the conveying direction of the metal sheet 2 by the conveying device 12.

[0014] The coating device 14 is a device that applies an active material paste 4 to the surface of the metal sheet 2. The active material paste 4 is a paste that contains at least an active material, and its specific configuration is not particularly limited. The coating device 14 is disposed on the transport path of the metal sheet 2 by the transport device 12, and applies the active material paste 4 to the surface of the metal sheet 2 being transported. The active material paste 4 is widely coated on the surface of the metal sheet 2 except for both end portions (see FIG. 3, etc.).

[0015] The drying device 16 is a device for applying the active material paste 4. The drying device 16 is also disposed on the path along which the metal sheet 2 is conveyed by the conveying device 12. The drying device 16 is located downstream of the coating device 14 in the conveying direction X of the metal sheet 2, and quickly dries the active material paste 4 applied to the surface of the metal sheet 2.

[0016] As shown in Figs. 2 and 3, the drying device 16 includes a plurality of light sources 20, 30. The plurality of light sources 20, 30 irradiate the active material paste 4 applied to the surface of the metal sheet 2 with laser light L. This heats and dries the active material paste 4. Note that the plurality of light sources 20, 30 are not limited to laser light L, and may be any light that irradiates light capable of heating the active material paste 4. Note that the direction Y shown in the figures indicates the width direction of the metal sheet 2, and is perpendicular to the conveying direction X.

[0017] With the above-described configuration, in the electrode sheet manufacturing method using the manufacturing apparatus 10, a coating step is carried out in which an active material paste 4 is applied to the surface of the metal sheet 2 while the long metal sheet 2 is being transported. In parallel with the coating step, a drying step is carried out in which the active material paste 4 applied to the surface of the metal sheet 2 is irradiated with laser light L from the multiple light sources 20, 30, thereby drying the active material paste 4.

[0018] The multiple light sources 20, 30 include multiple first light sources 20 and multiple second light sources 30. The first light source 20 irradiates the laser light L to a range in the width direction Y of the metal sheet 2 through which the first portion 2a passes. The second light source 30 irradiates the laser light L to a range in the width direction Y of the metal sheet 2 through which the second portion 2b passes. Here, the first portion 2a and the second portion 2b do not overlap each other and are adjacent to each other without any gaps in the width direction Y. The first portion 2a and the second portion 2b include the entire width of the active material paste 4 applied to the metal sheet 2, and the applied active material paste 4 is always irradiated with the laser light L.

[0019] The first irradiation area 20a to which the first light source 20 irradiates the laser light L and the second irradiation area 30a to which the second light source 30 irradiates the laser light L are different in position in the conveying direction X of the metal sheet 2. In other words, the first irradiation area 20a and the second irradiation area 30a are not adjacent to each other in the width direction Y. With this configuration, a time difference can be provided between the timing at which the laser light L is irradiated to the first portion 2a and the timing at which the laser light L is irradiated to the second portion 2b in the width direction Y of the metal sheet 2. The light is not irradiated simultaneously over the entire width of the applied active material paste 4, and the temperature rise of the metal sheet 2 is suppressed. By suppressing the temperature rise of the metal sheet 2, the thermal contraction of the metal sheet 2 accompanying the subsequent temperature drop is also suppressed, and the occurrence of unintended deformation (e.g., wrinkles) in the metal sheet 2 can be avoided.

[0020] In addition, by using a plurality of light sources 20, 30, the size of each of the light sources 20, 30 can be reduced. Also, the distance between each of the light sources 20, 30 and the metal sheet 2 can be relatively short. This allows the drying device 16 to be made compact.

[0021] Although not particularly limited, the first irradiation areas 20a by the first light sources 20 are arranged along the conveying direction X of the metal sheet 2 and are spaced apart from each other. As a result, a non-irradiation area 20b where the laser light L is not irradiated is provided between two adjacent first irradiation areas 20a. Similarly, the second irradiation areas 30a by the second light sources 30 are arranged along the conveying direction X of the metal sheet 2 and are spaced apart from each other. As a result, a non-irradiation area 30b where the laser light L is not irradiated is also provided between two adjacent second irradiation areas 30a. According to this configuration, in both the first portion 2a and the second portion 2b, the active material paste 4 applied to the metal sheet 2 is intermittently irradiated with the laser light L as the metal sheet 2 is conveyed. The metal sheet 2 and the active material paste 4 heated in the irradiation areas 20a and 30a of the laser light L are cooled while passing through the non-irradiation areas 20b and 30b, so that the temperature rise of the metal sheet 2 is further suppressed.

[0022] Although not particularly limited, the multiple first irradiation areas 20a by the multiple first light sources 20 and the multiple second irradiation areas 30a by the multiple second light sources 30 are arranged alternately one by one in the conveying direction X of the metal sheet. That is, the multiple first irradiation areas 20a and the multiple second irradiation areas 30a are arranged in a staggered pattern. With this configuration, it is possible to reduce the dimension in the conveying direction X required for the drying process while suppressing the temperature rise of the metal sheet 2.

[0023] In the above-mentioned manufacturing apparatus 10 and the manufacturing method using the same, the entire width of the applied active material paste 4 is divided into two, and each of the portions 2a and 2b is dried by the first light source 20 or the second light source 30. In contrast, as shown in FIG. 3, the entire width of the applied active material paste 4 may be divided into three, and the multiple light sources may further include a third light source 40 corresponding to the three portions. The third light source 40 irradiates the laser light L to a range in the width direction Y of the metal sheet 2 through which the third portion 2c passes. The third portion 2c is a portion adjacent to the second portion 2b from the opposite side to the first portion 2a. The first portion 2a, the second portion 2b, and the third portion 2c include the entire width of the active material paste 4 applied to the metal sheet 2.

[0024] The third irradiation areas 40a of the third light sources 40 are arranged along the conveying direction X of the metal sheet 2, similar to the other irradiation areas 20a and 30a described above, and are spaced apart from each other. However, the third irradiation areas 40a and the first irradiation areas 20a of the first light sources 20 are aligned in the conveying direction X of the metal sheet 2. That is, all the irradiation areas 20a, 30a, and 40a are arranged in a staggered pattern as a whole. With this configuration, the irradiation areas 20a, 30a, and 40a of the individual light sources 20, 30, and 40 can be made smaller, thereby further suppressing the temperature rise of the metal sheet 2. [Explanation of symbols]

[0025] 2: metal sheet, 4: active material paste, 10: manufacturing device, 12: conveying device, 14: coating device, 16: drying device, 20, 30, 40: light source, 20a, 30a, 40a: irradiated area, 20b, 30b: non-irradiated area

Claims

1. A method for producing an electrode sheet, comprising: a coating step of coating a surface of a long metal sheet with an active material paste while conveying the metal sheet; a drying step, which is carried out in parallel with the coating step, of drying the active material paste applied to the surface of the metal sheet by irradiating the active material paste applied to the surface of the metal sheet with light from a plurality of light sources; Equipped with The plurality of light sources includes at least one first light source and at least one second light source, The first light source irradiates light onto a range through which a first portion in a width direction of the metal sheet passes, and does not irradiate light onto a second portion in the width direction of the metal sheet, the second portion being adjacent to the first portion and through which the second portion passes, The second light source irradiates light onto an area through which the second portion of the metal sheet passes, and does not irradiate light onto the first portion of the metal sheet; a first irradiation range to which the first light source irradiates light and a second irradiation range to which the second light source irradiates light are different in position in a conveying direction of the metal sheet; Manufacturing method.

2. The plurality of light sources include a plurality of the first light sources and a plurality of the second light sources, The first illumination ranges of the first light sources are arranged along a conveying direction of the metal sheet and are spaced apart from each other, The second illumination ranges of the second light sources are arranged along a conveying direction of the metal sheet and are spaced apart from each other. The method of claim 1 .

3. The manufacturing method according to claim 2 , wherein the plurality of first irradiation areas by the plurality of first light sources and the plurality of second irradiation areas by the plurality of second light sources are arranged alternately one by one in the conveying direction of the metal sheet.

4. The method according to claim 1 , wherein the first and second portions of the metal sheet encompass an entire width of the active material paste applied to the metal sheet.

5. The plurality of light sources further includes a plurality of third light sources, The third light source irradiates light to a range through which the third portion passes, the third portion being adjacent to the second portion from the opposite side to the first portion, in a width direction of the metal sheet, The third illumination ranges by the third light sources are arranged along a conveyance direction of the metal sheet and are spaced apart from each other, the third illumination ranges are aligned with the first illumination ranges by the first light sources in a conveying direction of the metal sheet; The method of claim 3 , wherein the first portion, the second portion, and the third portion of the metal sheet encompass an entire width of the active material paste applied to the metal sheet.

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