JP6156070B2 - Battery electrode manufacturing equipment - Google Patents

Description

  The present invention relates to an electrode manufacturing apparatus used for a battery.

  Conventionally, in the manufacture of electrodes used in batteries, an electrode material is applied to the surface of a substrate and dried to produce an electrode sheet, and then the electrode sheet is compressed by a press device or the like to increase the density of the electrode layer. It has been. However, the region where the electrode layer is formed, that is, the base material of the coated region where the electrode material is applied is stretched by compression, but the region where the electrode layer is not formed, that is, the non-coated region where the electrode material is not coated. The base material does not stretch because no pressure is applied, and the electrode sheet is curved.

  Therefore, conventionally, processing for suppressing the bending of the electrode sheet that occurs after compression has been performed. For example, in Patent Document 1, a large-diameter portion of a guide roller having a small-diameter portion and a large-diameter portion is brought into contact with a non-application region of a compressed electrode sheet, and stress corresponding to the tension applied to the electrode sheet is not applied. The curvature of the electrode sheet is corrected by concentrating on the application area and extending the non-application area.

JP2013-73690A

  However, in Patent Document 1, in order to prevent the coating region of the electrode sheet from coming into contact with the large-diameter portion and applying a stress corresponding to the tension applied to the electrode sheet to the coating region, The coating region including the boundary region between the region and the coating region is set so as to be opposed to the small diameter portion. For this reason, in the non-coating region near the boundary, there is a portion that does not contact the large diameter portion and is not stretched, and there is a problem that the correction of the curve becomes insufficient.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

(1) According to one aspect of the present invention, an electrode manufacturing apparatus for a battery is provided. The electrode manufacturing apparatus for a battery of this form is a coating region where the electrode layer is applied along the longitudinal direction on the surface of the belt-shaped substrate, and a non-coating region where the electrode layer is not applied, A pressing portion for compressing the electrode sheet; and a curl correcting roller having a small diameter portion and a large large diameter portion along the width direction of the electrode sheet, wherein the small diameter portion is in the coating region of the electrode sheet. The large-diameter portion has a curvature correcting roller disposed opposite to the non-coated region of the electrode sheet, and the non-coated region of the electrode sheet is brought into contact with the large-diameter portion. And a curvature correcting part that corrects the curvature of the non-coated area of the electrode sheet by applying tension to the non-coated area of the electrode sheet. And, the boundary between the coating region and the non-coating region of the electrode sheet is located on the large diameter part side of the boundary between the large diameter part and the small diameter part of the curvature correcting roller, The width of the small-diameter portion along the width direction of the electrode sheet is set smaller than the width of the coating region along the width direction of the electrode sheet. According to the battery electrode manufacturing apparatus of this embodiment, as described in the problem, the non-coating region near the boundary between the coating region and the non-coating region is brought into contact with the large diameter portion of the curvature correcting roller. A portion that does not extend without contacting the large-diameter portion does not occur, and the remaining portion where the curvature is not corrected can be suppressed.

  In addition, this invention can be implement | achieved with various forms, for example, can be implement | achieved with the form of the manufacturing method of the electrode for batteries other than the electrode manufacturing apparatus for batteries.

It is explanatory drawing which shows the structure of the electrode manufacturing apparatus as 1st Embodiment. It is explanatory drawing shown in the state which looked at the correction roller from the downstream. It is a table | surface which shows the evaluation result of the curvature suppression in each correction roller from which the width | variety of a small diameter part differs. It is explanatory drawing shown in the state which looked at the correction roller of the electrode manufacturing apparatus as 2nd Embodiment from the downstream. It is a table | surface which shows the evaluation result of the curvature suppression in each correction roller from which the width | variety of a small diameter part differs.

A. First embodiment:
FIG. 1 is an explanatory diagram showing a configuration of an electrode manufacturing apparatus as the first embodiment. FIG. 1A shows a schematic plan view of the electrode manufacturing apparatus 10 as viewed from above, and FIG. 1B shows a schematic side view of the electrode manufacturing apparatus 10 as viewed from the side. In the figure, arrows X, Y, and Z indicate three directions orthogonal to each other. The electrode manufacturing apparatus 10 is an electrode manufacturing apparatus suitable for an apparatus for manufacturing an electrode for a secondary battery, particularly an electrode for a lithium ion battery. The electrode manufacturing apparatus 10 includes an unwinding unit 100, a coating unit 200, a press unit 300, a curvature correcting unit 400, and a winding unit 500.

  The coating unit 200 is an apparatus that coats the electrode layer TL on both surfaces (surfaces facing the Z direction) of the belt-shaped base sheet. The coating unit 200 is based on the longitudinal direction (X direction) of the strip-shaped substrate sheet S0 that is unwound from the substrate sheet roll R1 set on the unwinding roller 102 of the unwinding unit 100 and conveyed. An electrode material is applied to the center of both surfaces of the material sheet S0, and the electrode sheet S1 in which the electrode layer TL is continuously formed in the center of both surfaces of the base material sheet S0 is produced. The electrode sheet S1 includes a region A1 corresponding to the electrode layer TL (hereinafter also referred to as “coating region A1”) and a non-exposed substrate sheet that is not coated with an electrode material outside the coating region A1. A coating region A2 is formed. In addition, the coating machine and dryer used for application | coating of electrode material are not specifically limited, A various coating machine and dryer are used. As a base material sheet, various strip | belt-shaped metal foils, such as aluminum foil, aluminum alloy foil, copper foil, are used, for example. As the electrode material, a slurry or paste containing an active material is used. The active material of the positive electrode is not particularly limited, and various oxides such as lithium cobalt composite oxide and lithium manganese composite oxide are used. The active material of the negative electrode is not particularly limited, and carbon materials, lithium titanate materials, oxide materials, alloy materials, Li metal materials, and the like are used.

  The press unit 300 includes a pair of press rollers 302a and 302b. The pair of press rollers 302a and 302b are arranged so as to sandwich the electrode sheet S1 from both surfaces (surfaces facing the Z direction). The press unit 300 rotates the pair of press rollers 302a and 302b around the axis along the Y direction by a not-shown press roller driving mechanism, thereby sandwiching the electrode sheet S1 sandwiched between the pair of press rollers 302a and 302b. Is an apparatus for compressing and molding the electrode layer TL formed on both surfaces of the base sheet.

  The winding unit 500 includes a winding roller 502 having an axis along the Y direction, and is compressed by the press unit 300 by rotating the winding roller 502 by a winding driving mechanism (not shown). It is an apparatus which winds up electrode sheet S1 in roll shape and makes it electrode sheet roll R2.

  The curvature correction unit 400 includes two guide rolls 410 and 430 and a correction roller 420. The two guide rolls 410 and 430 are disposed so as to be in contact with the surface facing the lower side of the vertical direction (Z direction) of the electrode sheet S1 conveyed from the press unit 300 to the winding unit 500 and to support the electrode sheet S1. The The correction roller 420 has a vertical direction (Z direction) between the upstream guide roll 410 and the downstream guide roll 430 on the surface opposite to the surface of the electrode sheet S1 that is in contact with the two guide rolls 410 and 430. ) And the electrode sheet S1 is disposed so as to be in pressure contact with each other.

  Here, in the press unit 300, the pressure applied to the electrode sheet S1 by the pair of press rollers 302a and 302b is substantially applied to the coating region A1 in which the electrode layer TL is formed in the electrode sheet S1, and the non-coating region A2 Hardly participates. For this reason, in the coating area A1 of the electrode sheet S1, elongation along the longitudinal direction occurs according to the applied pressure, whereas almost no elongation occurs in the non-coating area A2 of the electrode sheet S1. A difference in elongation occurs between the coating area A1 and the non-coating area A2, and as a result, the electrode sheet S1 is curved in the longitudinal direction and the width direction (direction perpendicular to the longitudinal direction).

  The curvature correction unit 400 is a device that corrects the curvature generated by rolling of the electrode sheet S1 in the press unit 300 by extending the non-coated region A2 of the electrode sheet S1 along the longitudinal direction by the correction roller 420.

  FIG. 2 is an explanatory view showing the correction roller as seen from the downstream side. The correction roller 420 has a cylindrical large-diameter portion 421 and a small-diameter portion 422 having different diameters. The small diameter part 422 forms the center part of the correction roller 420, and the large diameter part 421 forms both end parts of the correction roller 420. A corner portion 421b on the small diameter portion 422 side of the large diameter portion 421 is chamfered to form an R surface (round surface) having a radius rc. Hereinafter, the corner portion 421b is also referred to as a “chamfered portion 421b”. The radius rc is also referred to as “chamfer dimension rc”.

The width Wa of the small diameter portion 422 of the correction roller 420 is set smaller than the width Wb of the coating area A1 of the electrode sheet S1 and satisfies the following formula (1).
Wa ≦ Wb−2 · rc (1)
Further, the width of the large-diameter portion 421 of the correction roller 420 is such that the width Wr of the correction roller 420 is larger than the width Ws of the electrode sheet S1, and the outer end SL of the non-coated area A2 of the electrode sheet S1 is large. It is set so as to be in contact with the pressure contact surface portion 421a of the diameter portion 421.

  When satisfy | filling said Formula (1), the whole width direction of the non-coating area | region A2 from boundary BL of coating area | region A1 and non-coating area | region A2 to edge part SL is the pressure-contact surface part of the large diameter part 421 of the correction roller 420 Since the sheet is pressed by 421a and is stretched in the longitudinal direction by a stress corresponding to the tension applied to the electrode sheet S1, there is no region that is not sufficiently pressed near the boundary BL of the non-coated area A2. Therefore, it is possible to suppress a region in which the curvature is not sufficiently corrected from remaining in the vicinity of the boundary BL of the non-coated region A2.

  The effect when the width Wa of the small diameter portion 422 of the correction roller 420 is set to satisfy the above formula (1) was confirmed as described below.

  Using a strip-shaped aluminum foil having a thickness of 15 [μm] and a width Ws of 145 [mm] as a base material sheet, an electrode material is applied in the coating unit 200 to produce an electrode sheet S1 having a thickness of 160 [μm]. did. The width Wb of the coating region A1 (electrode layer TL) of the electrode sheet S1 was 115 [μm]. As the electrode material, a paste containing a lithium cobalt composite oxide as an active material was used. The tension applied to the electrode sheet S1 on the upstream side of the press unit 300 is 45 [N], the tension applied to the electrode sheet S1 on the downstream side of the press unit 300 is 100 [N], and the electrode sheet S1 is thick in the press unit 300. The thickness was rolled from 160 [μm] to a thickness of 124 [μm]. At this time, the occurrence of bending due to the difference in elongation in the longitudinal direction between the coating area A1 and the non-coating area A2 was confirmed. Each of these numerical conditions is an example, and is not limited to these.

Suppression of bending is measured by measuring the amount of bending after correcting the bending of the electrode sheet S1 produced as described above with five types of correction rollers 420 having different widths Wa of the small-diameter portion 422. The effect of was confirmed. The following five types were selected as the width Wa of the small diameter portion 422.
(1) Wa = 116 [mm] (Condition 1: Wa> Wb, Wa> Wb-2 · rc)
(2) Wa = 115 [mm] (Condition 2: Wa = Wb, Wa> Wb-2 · rc)
(3) Wa = 114 [mm] (Condition 3: Wa <Wb, Wa <wb-2 · rc)
(4) Wa = 113 [mm] (Condition 4: Wa <Wb, Wa <Wb-2 · rc)
(5) Wa = 112 [mm] (Condition 5: Wa <Wb, Wa <Wb-2 · rc)
The diameter φB of the small diameter portion 422 of the correction roller 420 was 100 mm. Then, the diameter φA of the large-diameter portion 421 of the correction roller 420 is slightly larger than the diameter φB, for example, a size (φB + 2 · rc that is twice as large as the chamfering dimension rc of the chamfered portion 421 of the large-diameter portion 421. ). The chamfer dimension rc was 0.3 [mm].

  FIG. 3 is a table showing the evaluation results of curving suppression in each of the correction rollers having different widths of the small diameter portion. Under conditions 3 and 4 satisfying the above formula (1), the curvature was 0 [mm / 2 m]. Under condition 2 where the width Wa of the small diameter portion 422 is equal to the width Wb of the coating area A1, a curve of 2.0 [mm / 2 m] remains, and the width Wa of the small diameter section 422 is larger than the width Wb of the coating area A1. The larger condition 1 resulted in a 4.0 [mm / 2 m] curve that remained larger than condition 2. The bending amount [mm / 2m] is a value obtained by measuring the amount [mm] of a 2 m long electrode that is bent and displaced with respect to one end in the length direction on a flat substrate.

  In condition 2, there is a region in the vicinity of the boundary BL in the non-coated region A2 of the electrode sheet S1 where pressure contact is not performed or pressure contact is insufficient (hereinafter referred to as “a region where pressure contact is insufficient”). Therefore, the correction of the curve becomes insufficient and the curve remains. In condition 1, the width Wa of the small-diameter portion 422 is larger than the width Wb of the coating area A1, and the area where pressure contact is insufficient in the area near the boundary BL of the non-coating area A2 is wider than in the case of condition 2. Therefore, it is considered that the region where the curve remains is widened in the width direction, and the curve is larger than in the case of Condition 2. In the condition 3 and the condition 4, the entire width from the end portion SL of the non-coating region A2 to the boundary BL is press-contacted by the press-contact surface portion 421a of the large-diameter portion 421, and from the end portion SL of the non-coating region A2 to the boundary BL. It is considered that the entire width can be extended in the longitudinal direction, and the curvature is sufficiently corrected.

  In addition, although the said Formula (1) was satisfy | filled also in the conditions 5, the result that 1.0 [mm / 2m] curvature remains was shown. This is because the smaller the width Wa of the small-diameter portion 422, the larger the difference from the width Wb of the coating region A1, thereby increasing the area of the coating region A1 pressed by the pressure-contact surface portion 421a of the large-diameter portion 421. Therefore, it is considered that the stress applied to the non-coating area A2 is reduced and the curvature correction is insufficient. For this reason, there is an allowable upper limit for the difference between the width Wa of the small-diameter portion 422 and the width Wb of the coating region A1. Judging from the above results, the upper limit value is preferably less than 3 [mm], and more preferably less than 2.5 [mm].

  From the above results, in the correction roller 420 of the present embodiment, the curvature generated by the compression of the electrode layer TL is corrected by setting the width Wa of the small-diameter portion 422 to a width that satisfies the above formula (1). confirmed. Therefore, in the electrode manufacturing apparatus 10 of the present embodiment, it is possible to suppress a region that is not pressed against the non-coated region of the electrode sheet from being stretched and a region in which the curvature is not corrected remains.

  The difference between the diameter φA of the large diameter portion 421 of the correction roller 420 and the diameter φB of the small diameter portion 422 is 0.6 [mm] (diameter φB = 0.6% with respect to 100 mm). The difference in φB is slight. Therefore, the correction roller 420 is preferably formed of a rigid body such as metal so as not to be deformed by tension.

B. Second embodiment:
FIG. 4 is an explanatory view showing the straightening roller of the electrode manufacturing apparatus as the second embodiment as seen from the downstream side. Since the electrode manufacturing apparatus of the second embodiment is the same as the electrode manufacturing apparatus 10 of the first embodiment except for the correction roller 420B, only the correction roller 420B will be described below.

  Similar to the correction roller 420 of the first embodiment, the correction roller 420B of the present embodiment has a cylindrical large-diameter portion 421B and a small-diameter portion 422 having different diameters. The small diameter part 422 forms the central part of the correction roller 420, and the large diameter part 421B forms both end parts of the correction roller 420B. The corner portion 421Bb on the small diameter portion 422 side of the large diameter portion 421B has a tapered shape with a taper width of wc. The taper ratio 1 / x is not particularly limited, but it is desirable that x ≧ 1. Hereinafter, the corner portion 421Bb is also referred to as a “taper portion 421Bb”. The correction roller 420B is also preferably configured using a metal and high-rigidity material, like the correction roller 420 of the first embodiment.

The width Wa of the small-diameter portion 422 of the correction roller 420B is set smaller than the width Wb of the coating region A1 of the electrode sheet S1 and satisfies the following formula (2).
Wa ≦ Wb−2 · wc (2)
Further, the width Wr of the correction roller 420B is such that the outer end portion SL of the non-coated area A2 of the electrode sheet S1 is in contact with the pressure contact surface portion 421Ba of the large diameter portion 421B. It is set larger than the width Ws of the electrode sheet S1.

  When satisfy | filling said Formula (2), the whole width direction of the non-coating area | region A2 from boundary BL of coating area | region A1 and non-coating area | region A2 to edge part SL is the press-contact surface part of the large diameter part 421B of the correction roller 420B. Since it is pressed by 421Ba and stretched in the longitudinal direction by a stress corresponding to the tension applied to the electrode sheet S1, there is no region that is not sufficiently pressed near the boundary BL of the non-coated region A2. Therefore, it is possible to suppress a region in which the curvature is not sufficiently corrected from remaining in the vicinity of the boundary BL of the non-coated region A2.

  The effect when the width Wa of the small diameter portion 422 of the correction roller 420B is set to satisfy the above formula (2) was confirmed as described below.

Measuring the amount of bending after correcting the bending of the electrode sheet S1 produced under the same conditions as in the first embodiment, using the five types of correction rollers 420B under different conditions of the width Wa of the small-diameter portion 422. Thus, the effect of curving suppression was confirmed. The following five types were selected as the width Wa of the small diameter portion 422.
(1) Wa = 115 [mm] (Condition 1: Wa = Wb, Wa> Wb-2 · wc )
(2) Wa = 114 [mm] (Condition 2: Wa <Wb, Wa> Wb-2 · wc)
(3) Wa = 113 [mm] (Condition 3: Wa <Wb, Wa = Wb−2 · wc )
(4) Wa = 112 [mm] (Condition 4: Wa <Wb, Wa <Wb-2 · wc )
(5) Wa = 111 [mm] (Condition 5: Wa <Wb, Wa <Wb-2 · wc )
The tapered width wc of the tapered portion 421Bb of the large diameter portion 421B is 1.0 mm.

  FIG. 5 is a table showing evaluation results of curving suppression in each of the correction rollers having different widths of the small diameter portion. Under conditions 3 and 4 satisfying the above equation (2), the curvature was 0 [mm / 2 m]. Although the width Wa of the small-diameter portion 422 is smaller than the width Wb of the coating region A1, under the condition 2 that does not satisfy the condition of the above formula (2), a curve of 2.0 [mm / 2 m] remains. . In condition 1 where the width Wa of the small diameter portion 422 and the width Wb of the coating area A1 are equal, a curve of 3.0 [mm / 2 m] larger than the condition 2 remains.

  In condition 2, since the boundary BL of the non-coated area A2 of the electrode sheet S1 is in contact with the tapered surface of the large diameter part 421B, the pressure contact is insufficient in the area near the boundary BL of the non-coated area A2. There will be a region, the curvature will be insufficiently corrected and the curvature will remain. In condition 1, the width Wa of the small-diameter portion 422 is equal to the width Wb of the coating area A1, and the area where pressure contact is insufficient in the area near the boundary BL of the non-coating area A2 is wider than in the case of condition 2. Therefore, it is considered that the region where the curve remains is widened, and the curve is larger than in the case of condition 2. In Condition 3 and Condition 4, the entire width from the end portion SL of the non-coating region A2 to the boundary BL is pressed by the press-contact surface portion 421Ba of the large-diameter portion 421B, and from the end portion SL of the non-coating region A2 to the boundary BL. It is considered that the entire width can be extended in the longitudinal direction, and the curvature is sufficiently corrected.

  In condition 5, the condition of the above formula (2) was satisfied, but a result of 1.0 [mm / 2 m] of curvature remaining was shown. This is because the smaller the width Wa of the small-diameter portion 422, the larger the difference from the width Wb of the coating region A1, thereby increasing the coating region A1 pressure-contacted by the pressure-contact surface portion 421a of the large-diameter portion 421B. Therefore, it is considered that the stress applied to the non-coating area A2 is reduced and the curvature correction becomes insufficient. For this reason, there is an allowable upper limit for the difference between the width Wa of the small-diameter portion 422 and the width Wb of the coating region A1. Judging from the above results, the upper limit is preferably less than 4 [mm], and more preferably less than 3.5 [mm].

  From the above results, in the correction roller 420B of the present embodiment, the curvature generated by the compression of the electrode layer TL is corrected by setting the width Wa of the small diameter portion 422 to satisfy the above formula (2). It was confirmed. Therefore, also in the present embodiment, as in the first embodiment, it is possible to suppress a region that is not pressed against the non-coated region of the electrode sheet from being stretched and a region in which the curvature is not corrected remains. It is.

In the confirmation of the effect when the correction roller 420B has the width Wa of the small-diameter portion 422 that satisfies the above formula (2), each set numerical value is an example, and is not limited thereto. It can be applied under various conditions that satisfy (2) .

C. Variations:
In the above embodiment, the electrode manufacturing apparatus including the coating unit, the press unit, and the curvature correcting unit has been described as an example. However, the coating unit is omitted, and the strip-shaped electrode is unwound from the unwinding unit and conveyed. It is good also as an electrode manufacturing apparatus which rolls a sheet | seat with a press part, and correct | amends curvature by a curvature correction part.

  Moreover, in each said embodiment, although the structure which arrange | positions one correction roller was demonstrated to the example, it is good also as a structure which arrange | positions a some correction roller.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Moreover, elements other than the elements described in the independent claims among the constituent elements in the above-described embodiments and modifications are additional elements and can be omitted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Electrode manufacturing apparatus 100 ... Unwinding part 102 ... Unwinding roller 200 ... Coating part 300 ... Press part 302a, 302b ... Press roller 400 ... Curvature correction part 410,430 ... Guide roll 420 ... Correcting roller 420B ... Correcting roller 421 ... large diameter part 421B ... large diameter part 421a ... pressure contact surface part 421b ... corner part (chamfered part)
421Ba: Pressure contact surface portion 421Bb: Corner portion (tapered portion)
422 ... Small diameter part 500 ... Winding part 502 ... Winding roller S0 ... Base sheet S1 ... Electrode sheet A1 ... Coating area A2 ... Non-coating area TL ... Electrode layer BL ... Border SL ... End R1 ... Base sheet Roll R2 ... Electrode sheet roll

Claims (1)

An electrode manufacturing apparatus for a battery,
A coating region in which an electrode layer is applied along the longitudinal direction in the center in the width direction of the surface of the band-shaped substrate, and the electrode layer is not applied on both sides of the coating region in the width direction An electrode sheet having a non-coating region, and a pressing unit that compresses the electrode sheet,
A curvature correcting roller having a small diameter portion and a large diameter portion having an outer diameter larger than the small diameter portion along the width direction of the electrode sheet, the small diameter portion facing the coating region of the electrode sheet, The large-diameter portion has a curvature correcting roller arranged to face the non-coated region of the electrode sheet, and the electrode sheet is brought into contact with the non-coated region of the electrode sheet. A curvature correcting part for correcting the curvature of the non-coated area of the electrode sheet by applying a tension to the non-coated area;
With
The distance between the pressure contact surface portions of the large diameter portion on both sides of the small diameter portion is such that the boundary between the coating region and the non-coating region of the electrode sheet is in contact with the pressure contact surface portion of the large diameter portion. An electrode manufacturing apparatus for a battery, which is set to be equal to or smaller than the width of the coating region along the width direction of the sheet.

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