ORIGINAL SHEET DIVIDING METHOD AND DIVIDING MECHANISM AND DIVIDING APPARATUS THEREFOR
20210245302 · 2021-08-12
Inventors
Cpc classification
B23K26/08
PERFORMING OPERATIONS; TRANSPORTING
B23K26/083
PERFORMING OPERATIONS; TRANSPORTING
B23K26/0846
PERFORMING OPERATIONS; TRANSPORTING
B23K2101/34
PERFORMING OPERATIONS; TRANSPORTING
B23K26/0853
PERFORMING OPERATIONS; TRANSPORTING
International classification
B21D43/04
PERFORMING OPERATIONS; TRANSPORTING
B23K26/08
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Provided is an epoch-making original sheet dividing method in which an original sheet is cut while being conveyed and which enables a continuous operation to be performed for a long period of time without occurrence of burrs at cut end faces, without scattering cutting dust, and without time and effort for component replacement.
The original sheet dividing method is an original sheet dividing method for cutting an original sheet 1 having an active material layer applied to at least one surface of a long metal foil 4, with a laser beam L in a longitudinal direction. The original sheet 1 is continuously moved. While the original sheet 1 is moved, the laser beam L is applied to the original sheet 1 to melt the original sheet 1 at an irradiation point P. At a downstream side of the irradiation point P of the laser beam L, one divided original sheet 1s is pulled upward relative to a feed surface of the original sheet 1, and adjacent another original sheet 1t is pulled downward relative to the feed surface of the original sheet 1, thereby separating the slit original sheets 1s and 1t adjacent to each other at the irradiation point P.
Claims
1. An original sheet dividing method for cutting an original sheet having an active material layer applied to at least one surface of a long metal foil, with a laser beam in a longitudinal direction, the original sheet dividing method comprising: continuously moving the original sheet while applying the laser beam to the original sheet to melt the original sheet at an irradiation point; causing a moving direction of one divided original sheet to be upward or downward relative to a moving direction of another divided original sheet at a downstream side of the irradiation point; and vertically separating the divided original sheets adjacent to each other at the irradiation point.
2. The original sheet dividing method according to claim 1, wherein the original sheet is cut while the laser beam is caused to reciprocate along a running direction of the original sheet.
3. The original sheet dividing method according to claim 1, wherein a separating member is disposed at the downstream side of the irradiation point, and the one divided original sheet is caused to move over the separating member or pass below the separating member to make the moving direction of the one divided original sheet different from the moving direction of the other original sheet.
4. An original sheet dividing mechanism for cutting a running original sheet having an active material layer applied to at least one surface of a long metal foil, with a laser beam in a longitudinal direction, the original sheet dividing mechanism comprising: a laser emission device disposed above the original sheet and configured to apply the laser beam to the original sheet to divide the original sheet; and a separating member disposed at a downstream side of an irradiation point of the laser beam so as to be in contact with a lower surface of one divided original sheet and configured to raise the divided original sheet, or disposed at the downstream side of the irradiation point of the laser beam so as to be in contact with an upper surface of another divided original sheet and configured to press down the divided original sheet, thereby to make a moving direction of the one divided original sheet different from a moving direction of the other divided original sheet.
5. An original sheet dividing mechanism for cutting a running original sheet having an active material layer applied to at least one surface of a long metal foil, with a laser beam in a longitudinal direction, the original sheet dividing mechanism comprising: a laser emission device disposed above the original sheet and configured to apply the laser beam to the original sheet to divide the original sheet; and a separating member including a raising-side member disposed at a downstream side of an irradiation point of the laser beam so as to be in contact with a lower surface of one divided original sheet and configured to raise the divided original sheet and a pressing-side member disposed at the downstream side of the irradiation point of the laser beam so as to be in contact with an upper surface of another divided original sheet and configured to press down the divided original sheet, the separating member being configured to make a moving direction of the one divided original sheet different from a moving direction of the other divided original sheet.
6. The original sheet dividing mechanism according to claim 4, wherein the separating member is provided so as to move toward and away from the irradiation point.
7. The original sheet dividing mechanism according to claim 4, wherein the separating member is composed of a roller configured to rotate in contact with the divided original sheets.
8. The original sheet dividing mechanism according to claim 4, wherein the separating member is composed of a plate member having a cross-section parallel to a running direction of the original sheet, the cross-section having a thickness that gradually decreases as distance to an irradiation point side decreases.
9. An original sheet dividing apparatus for cutting a running original sheet having an active material layer applied to at least one surface of a long metal foil, with a laser beam in a longitudinal direction, the original sheet dividing apparatus comprising: an original sheet supply portion configured to continuously feed the original sheet; a laser emission device disposed above the fed original sheet and configured to apply the laser beam to the original sheet to divide the original sheet; a separating member disposed at a downstream side of an irradiation point of the laser beam so as to be in contact with a lower surface or an upper surface of at least one divided original sheet and configured to raise or press down the divided original sheet thereby to make a moving direction of the one divided original sheet different from a moving direction of another divided original sheet; and an original sheet take-up portion disposed at a downstream side of the separating member and configured to take up the divided original sheets.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DESCRIPTION OF EMBODIMENTS
[0057] Hereinafter, the present invention will be described by means of illustrated embodiments. As shown in
[0058] An applied original sheet 1 in
[0059] The metal foil 4 is, for example, a copper foil or an aluminum foil. The electrode paste contains an active material, a binder, and a solvent, etc. Examples of the active material include a positive electrode active material and a negative electrode active material.
[0060] The positive electrode active material contains, for example, a composite oxide, metal lithium, and sulfur, etc.
[0061] The negative electrode active material includes, for example, various carbons, an alkali metal such as lithium and sodium, a metal compound, a metal oxide of SiO.sub.x, and a boron-added carbon.
[0062] As the binder, a resin such as fluorine-containing resin, thermoplastic resin, and imide resin is used.
[0063] The original sheet supply portion 10 includes a feed-side servomotor 11 that is a feeding side, an original sheet feed shaft 12 connected to the feed-side servomotor 11, and an original sheet support stand (not shown). The original sheet 1 that is in the form of a roll and is suspended by the original sheet support stand is mounted to the original sheet feed shaft 12 and fed by the feed-side servomotor 11.
[0064] Next to the original sheet supply portion 10, the feed-side rollers 20a to 20n are installed. The feed-side rollers 20a to 20n convey the original sheet 1 fed from the original sheet supply portion 10 while keeping the original sheet 1 horizontal, and a roller 20d is incorporated in the middle as a publicly-known original sheet-side dancing roller for adjusting the tension of the original sheet 1 being fed. At the rearmost end of the feed-side rollers 20a to 20n, a pair of upper and lower feed-side rollers 20m and 20n are installed and serve to hold the sent original sheet 1 therebetween from above and below and send the original sheet 1 to a division region for the next process while keeping the original sheet 1 horizontal.
[0065] The downstream side of the feed-side rollers 20m and 20n at the rearmost end is the division region for the original sheet 1, and the laser emission device 30 is installed directly above the division region. In the drawing, the single laser emission device 30 is depicted, but a plurality of laser emission devices (not shown) can be installed according to the number of sections into which the original sheet 1 is to be divided. The laser emission device 30 divides the original sheet 1 merely into two sections, and thus a laser beam L thereof only needs to be fixed. However, the laser emission device 30 may be a galvano type laser emission device capable of moving the laser beam L as described later.
[0066] In the drawings, an irradiation point of the laser emission device 30 is shown by P. The irradiation point P is set to be close to and immediately rearward of the upper feed-side roller 20m at the rearmost end. The laser beam L may be emitted in a single mode, but a second-fourth harmonic laser (green laser), a picosecond laser, and a femtosecond laser, etc., which have higher output, may be used for reducing thermal effects on the active material.
[0067] To assuredly separate the original sheets 1s and 1t from each other, it is important that a portion melted at the irradiation point P is separated before becoming rejoined. For this, it is important that, at the downstream side of the irradiation point P, a moving direction of the one divided original sheet 1s is caused to be upward or downward relative to a moving direction of the other original sheet 1t and the divided original sheets 1s and 1t adjacent to each other at the irradiation point P are vertically separated from each other.
[0068] The above case includes a case (
[0069] The separating member 40 may not be used for the vertical separation, and the divided original sheets 1s and 1t may be taken up such that conveying directions of the original sheets 1s and 1t are displaced vertically relative to each other. However, by using the separating member 40 that will be described next, the original sheets 1s and 1t can be assuredly separated from each other.
[0070] The separating member 40 may be any member as long as the member vertically separates the original sheets 1s and 1t from each other before a melting material that is melted by the laser beam L at the irradiation point P becomes solidified, thereby preventing rejoining. In later-described examples, a roller or a sliding plate is used. As a matter of course, the separating member 40 is not limited to the roller and the sliding plate as long as the separating member 40 performs the above operation. The separating member 40 is movable toward and away from the irradiation point P so as to be able to change a division angle θ of the divided left and right original sheets 1s and 1t that are separated by the separating member 40.
[0071] In the former case, as shown in
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[0075]
[0076] In
[0077] The left separating roller 40a is configured to be brought into contact with the lower surface of the divided original sheet 1s to raise the divided original sheet 1s. Meanwhile, the right separating roller 40b is configured to be brought into contact with the upper surface of the divided original sheet 1t to press down the divided original sheet 1s. The illustrated separating rollers 40a and 40b are coaxial with each other, and rotate in contact with the divided original sheets 1s and 1t, respectively. Thus, the separating rollers 40a and 40b rotate in the moving direction of the divided original sheets 1s and 1t. The separating rollers 40a and 40b are provided so as to be rotatable in directions opposite to each other.
[0078] The illustrated separating rollers 40a and 40b are coaxial with each other. However, as a matter of course, the separating rollers 40a and 40b are not limited thereto, and may be mounted on different shafts so as to be rotatable in directions opposite to each other.
[0079] In the case where the number of the divided sections is equal to or larger than 3, adjacent separating rollers are set alternately such that one of the separating rollers raises the divided original sheet and the other separating roller presses down the divided original sheet so as to form a division angle θ between the adjacent divided original sheets. The plate-like separating member 40 in
[0080] The reception-side rollers 50a to 50n are provided at the downstream side of the separating rollers 40a and 40b. The reception-side rollers 50a to 50n send the divided original sheets 1s and 1t to the original sheet take-up portion 60 while keeping the divided original sheets 1s and 1t horizontal.
[0081] In the case where the divided original sheets 1s and 1t are raised and pressed down by the same amount by the separating rollers 40a and 40b as shown in
[0082] In the case where, as shown in
[0083] A take-up-side dancing roller is not installed as one of the illustrated reception-side rollers 50a to 50n in the drawing, but may be provided as necessary.
[0084] The original sheet take-up portion 60 is installed subsequent to the reception-side rollers 50a to 50n, and the divided original sheets 1s and 1t are taken up on a take-up shaft 62. A take-up servomotor 61 is connected to the take-up shaft 62 and rotates in synchronization with the feeding servomotor 11.
[0085] Next, operation of a first embodiment of the apparatus 100 will be described. The original sheet 1 is mounted on the original sheet feed shaft 12 as shown in
[0086] When the apparatus 100 is actuated in this state, the feed-side servomotor 11 operates to feed the original sheet 1 at a predetermined speed. At the same time, the take-up servomotor 61 rotates in synchronization with the feed-side servomotor 11, so that the divided original sheets 1s and 1t are taken up.
[0087] In the division region, the laser beam L is emitted from the laser emission device 30 toward the original sheet 1, and the active material and the metal foil 4 of the original sheet 1 instantaneously melt at the irradiation point P. In the present invention, during emission of the laser beam L, assist gas is not sprayed toward the irradiation point P as in the conventional art, and thus the melting material is not blown away and stays at the irradiation point P.
[0088] Since the original sheet 1 is continuously fed, the irradiation point P linearly moves in accordance with the movement of the original sheet 1. Owing to the action of the pair of left and right separating rollers 40a and 40b described above, the adjacent divided left and right original sheets 1s and 1t are vertically separated from each other at the irradiation point P simultaneously with the melting. Thus, even when the melting material staying at the irradiation point P becomes solidified at the next moment at which the irradiation point P moves, the melting material cannot become rejoined, and remains at cut end faces and becomes solidified. As a result, the original sheets 1s and 1t are assuredly separated from each other. In addition, at this time, the cut ends are formed by fusion cutting, and the melting material becomes solidified at the cut ends in a round shape due to its surface tension as described above. Accordingly, burrs, which occur as a result of cutting with a blade, do not occur. When the melting material is blown away by assist gas as in the conventional art, the melting material that remains at the cut end faces is pulled by the blown-away melting material and remains as sharp thorns like icicles. However, in the present invention, such a phenomenon does not occur.
[0089] Moreover, since the melting material remains at the cut ends in a round shape, cutting dust, which occurs in the case of using assist gas, does not occur.
[0090] Since the original sheet 1 is continuously fed, the original sheet 1 is continuously divided as long as the laser beam L is emitted. The divided original sheets 1s and 1t are taken up on the take-up shaft 62 as described above. At this time, a dancing roller may be provided as one of the reception-side rollers 50a to 50n for tension adjustment, although not shown.
[0091] Next, a second embodiment will be described (
[0092] Meanwhile, a right portion of the separating member 40 is configured to be brought into sliding contact with the upper surface of the divided right original sheet 1t to press down the divided original sheet 1s. This portion is a pressing-down portion 40b. The separating member 40 is movable toward and away from the irradiation point P so as to be able to change the division angle θ of the divided left and right original sheets 1s and 1t. Since the separating member 40 is brought into sliding contact with the divided original sheets 1s and 1t as described above, the separating member 40 is preferably a hard resin having a low coefficient of friction (e.g., tetrafluoroethylene resin). The separating member 40 is provided so as to cover the entire length of the original sheet 1, but may be shorter than the width of the original sheet 1 as long as the separating member 40 does not impede feeding of the original sheet 1.
[0093] Next, a third embodiment of the present invention will be described with reference to
[0094]
[0095] Next, another method for dividing the original sheet 1 of the present invention will be described with reference to
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[0100] Then, when the active material layer of the lower surface portion 1d is melted, the left and right original sheets 1s and 1t are pulled vertically to be separated due to movement of the original sheet 1 toward the separating member 40, simultaneously with the melting, before rejoining of the melting material, so that the original sheet 1 is assuredly cut.
[0101] Here, the laser beam L reciprocates along the moving direction of the original sheet 1 with the angle α. When the laser beam L reciprocates at a constant angular velocity (the running speed on the original sheet 1 is also substantially the same speed), while the laser beam L moves in the same direction as the moving direction of the original sheet 1, the relative speed of the laser beam L to the original sheet 1 is decreased by the moving speed of the original sheet 1, and energy inputted by the applied laser beam L increases, so that the original sheet 1 is fusion-cut thin; and, on the other hand, while the laser beam L moves in a direction opposite to the moving direction of the original sheet 1, the relative speed of the laser beam L to the original sheet 1 is increased by an amount corresponding to the movement of the original sheet 1, and the energy inputted by the applied laser beam L decreases, so that the melting material is heated and shaped to be rounded. Accordingly, cleaner cut faces can be obtained.
[0102] The output of the laser emission device 30 can be freely changed by a program. Thus, it is possible to make the output for the active material layer different from that for the metal foil 4, and it is possible to cause the laser beam L to run on the cutting line in zigzag or while drawing a loop, although not shown. This point is applicable to the case where the laser beam L is not caused to reciprocate along the moving direction of the original sheet 1 as described above. That is, the laser beam L can be caused to zigzag or draw a loop by swinging the laser beam L laterally relative to the irradiation point P. Accordingly, the melting width of the irradiation point P can be increased.
[0103] As described above, by vertically spreading the melted original sheet 1 at the irradiation point P of the laser beam L, rejoining at the time of solidification of the melting material can be physically avoided, and the original sheet 1 can be assuredly divided while running.
REFERENCE SIGNS LIST
[0104] 1 original sheet
[0105] 1a active material layer (electrode portion)
[0106] 1b ear portion
[0107] 1d lower surface portion
[0108] 1s, 1t divided original sheet
[0109] 1u front surface portion
[0110] 4 metal foil
[0111] 5 tab
[0112] 10 original sheet supply portion
[0113] 11 feeding servomotor
[0114] 12 original sheet feed shaft
[0115] 20a to 20n feed-side roller
[0116] 20d original sheet-side dancing roller
[0117] 30 laser emission device
[0118] 40 separating member
[0119] 40a, 40a′ raising-side member (roller, portion, large-diameter portion)
[0120] 40b pressing-side member (roller, portion, small-diameter portion)
[0121] 40c holding roller
[0122] 50a to 50n reception-side roller
[0123] 60 original sheet take-up portion
[0124] 61 take-up servomotor
[0125] 62 take-up shaft
[0126] 100 original sheet dividing apparatus
[0127] 110 dividing mechanism
[0128] L laser beam
[0129] P irradiation point
[0130] θ separation angle
[0131] α oscillation angle of laser beam