JP2015066663A - Composite slitting method and slitter apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To wind up a scrap together with a composite material main body by leaving an insulating tape without cutting when a composite material produced by attaching an insulating tape made of synthetic resin having insulation properties to both surfaces of a positive electrode plate. Prevent that. A composite material 12 is cut by a first cutting portion 15 along a longitudinal direction P1. The insulating tape 11 left uncut by the first cutting section 15 is cut by the second cutting section 16 provided at a position downstream of the first cutting section 15 in the delivery direction P1. [Selection diagram] Fig. 3

Description

  The present invention relates to a slitting method and a slitter device for cutting a composite material in which an insulating tape having an insulating property is attached to an electrode in a longitudinal direction.

  As described in Patent Document 1, a flat film-shaped battery is known as a structure suitable for a lithium ion secondary battery having a relatively large capacity. This film-clad battery has a structure in which a power generation element formed by laminating a plurality of electrodes (positive electrode, negative electrode) and separator is housed in an exterior body made of a laminate film together with an electrolytic solution. The electrode is formed by forming an active material layer on both sides or one side of a metal foil such as an aluminum foil, and the active material layer is obtained by applying a mixture of an active material and a binder on the metal foil, drying and rolling. It is formed by.

JP 2003-303583 A JP 2008-279537 A

  In such a film-clad battery, the negative electrode active material layer is usually longer in the longitudinal direction than the positive electrode active material layer in order to smoothly store lithium ions released from the positive electrode active material layer during charging in the negative electrode active material layer. Is set. Accordingly, a part of the negative electrode active material layer is opposed to a part where the positive electrode active material layer is not coated, that is, a part where the metal foil of the positive electrode is exposed, with the separator interposed therebetween. Thus, if a short circuit occurs between the negative electrode active material layer facing each other and the part where the metal foil of the positive electrode is exposed, there is a problem that more current flows than a short circuit in the part where the active material layers face each other. is there.

  Therefore, a predetermined width insulating tape made of synthetic resin such as polypropylene (PP) is applied along the width direction of the positive electrode to the portion where the metal foil of the positive electrode is exposed, and a short circuit in this portion is surely ensured. Techniques for preventing it are known. However, when the insulating tape having a predetermined width is applied along the width direction of the electrode as described above, the following problems occur.

  A slitter device that cuts an electrode to a predetermined width is usually one that sandwiches an electrode with an upper blade and a lower blade and shears in order to cut a metal part with certainty (see Patent Document 2). For this reason, even if it is going to cut | disconnect the electrode of the state which stuck the insulating tape with said slitter apparatus, since an insulating tape is extended in a shear direction, there exists a possibility that an insulating tape may not be cut | disconnected well.

  Therefore, it is conceivable to apply an insulating tape to the electrode after cutting it to a predetermined width with a slitter device. However, in this case, it is difficult to apply the tape with accuracy, such as the tape protruding from the end.

  The present invention has been made in view of such circumstances. That is, in the present invention, a composite material in which an insulating tape having a predetermined width made of a synthetic resin having insulation properties is applied to an electrode having an active material layer formed on a metal foil along a width direction orthogonal to the longitudinal direction of the electrode. Is made. And the composite material of the state which affixed the insulating tape on the electrode in this way is cut | disconnected along the said longitudinal direction. By thus cutting the insulating tape together with the electrodes, the widthwise dimensions of the two can be matched with high accuracy. In addition, work efficiency is good because the work of attaching the insulating tape later is omitted.

  Preferably, the cutting step preferably includes a first cutting portion that cuts the composite material fed along the longitudinal direction at a predetermined position, and a position downstream of the first cutting portion in the delivery direction of the composite material. And a second cutting portion for cutting the insulating tape left without being cut by the one cutting portion. Therefore, even if the insulating tape is left without being cut at the first cutting portion, the insulating tape can be reliably cut by the second cutting portion located on the downstream side in the delivery direction.

  Here, when the composite material is separated into the composite material main body and the scrap by the first cutting part, the composite material main body and the scrap are separated from each other, so that the scrap is separated from the composite material main body. A predetermined tension (tension) is generated in the width direction with respect to the insulating tape bonded to both the scrap and the scrap. With this tension, when the insulating tape is cut by the second cutting portion, the insulating tape does not extend and cut in the cutting direction, and the insulating tape can be cut well.

  Preferably, the second cutting part cuts the insulating tape at a position closer to the scrap than the cutting line by the first cutting part in the width direction. That is, the second cutting part is configured to cut the insulating tape at a position spaced apart from the composite body in the width direction. Therefore, the side edge in the width direction of the composite material body along the cutting line cut by the first cutting portion is not interfered or cut by the second cutting portion.

  Since the second cutting part is spaced apart in the width direction from the composite body, the insulating tape is cut slightly longer in the width direction than the composite body by the second cutting part, but as described above. Since the insulating tape immediately before cutting has a predetermined tension in the width direction, the insulating tape shrinks slightly after cutting, so that the insulating tape does not protrude greatly from the composite body in the width direction.

  According to the present invention, by cutting the insulating tape together with the electrode, the work is easier and the width direction dimensions of both are matched with accuracy than when the insulating tape is applied to the cut electrode. Can be made.

The perspective view which shows an example of the film-clad battery in which the composite material by which the insulating tape was stuck to the electrode is used. The perspective view which shows the said film-clad battery. Explanatory drawing which shows the slit method of the composite material which concerns on a present Example. The perspective view which shows an example of the slitter apparatus of the composite material which concerns on a present Example. The perspective view which similarly shows an example of the said slitter apparatus.

  Hereinafter, the present invention will be described with reference to illustrated embodiments.

  First, based on FIG. 1 and FIG. 2, an example of a film-clad battery 1 provided with a positive electrode plate as an electrode according to the present invention will be described. The film-clad battery 1 is, for example, a lithium ion secondary battery, and has a flat rectangular external shape as shown in FIG. 1 and a pair of terminals made of conductive metal foil at one edge in the longitudinal direction. 2 and 3.

  As shown in FIG. 2, the film-clad battery 1 is a battery in which a rectangular power generation element 4 is accommodated in an exterior body 5 made of a laminate film together with an electrolytic solution. The power generating element 4 includes a plurality of positive plates 7 and negative plates 8 as electrodes stacked alternately with separators 6 interposed therebetween. In this example, the negative electrode plates 8 are positioned on both surfaces of the power generation element 4, but a configuration in which the positive electrode plate 7 is positioned on the outermost layer of the power generation element 4 is also possible. In addition, the dimension of each part in FIG. 2 is not necessarily exact, and is exaggerated for explanation.

  The positive electrode plate 7 is obtained by forming a positive electrode active material layer 7b on both surfaces of a rectangular positive electrode current collector 7a. The positive electrode current collector 7a is made of an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil. Further, the positive electrode active material layer 7b includes, for example, a positive electrode active material made of a lithium composite oxide such as lithium nickelate (LiNiO2), lithium manganate (LiMnO2), or lithium cobaltate (LiCoO2), and carbon black. It is formed by applying a mixture of a conductive additive and a binder to the main surface of the positive electrode current collector 7a, and drying and rolling.

  The negative electrode plate 8 has a negative electrode active material layer 8b formed on both sides of a rectangular negative electrode current collector 8a. The negative electrode current collector 8a is made of an electrochemically stable metal foil such as a nickel foil, a copper foil, a stainless steel foil, or an iron foil. The negative electrode active material layer 8b includes, for example, a binder for a negative electrode active material that occludes and releases lithium ions of the positive electrode active material, such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. Is applied to the main surface of the negative electrode current collector 8a, dried and rolled.

  A part of the longitudinal edge of the positive electrode current collector 7 a extends as an extension that does not include the positive electrode active material layer 7 b, and the tip thereof is joined to the positive electrode terminal 2. Similarly, although not shown in FIG. 2, a part of the edge in the longitudinal direction of the negative electrode current collector 8 a extends as an extension portion that does not include the negative electrode active material layer 8 b, and the tip thereof is the negative electrode terminal 3. It is joined to.

  The separator 6 has a function of preventing a short circuit between the positive electrode plate 7 and the negative electrode plate 8 and simultaneously holding an electrolyte, and is made of, for example, a polyolefin such as polyethylene (PE) or polypropylene (PP). When the overcurrent flows, the pores of the layer are blocked by the heat generation, and the current is cut off. The separator 6 is not limited to a single-layer film such as polyolefin, but can also be a three-layer structure in which a polypropylene film is sandwiched between polyethylene films, or a laminate of a polyolefin microporous film and an organic nonwoven fabric or the like. .

  Further, the electrolyte solution is not particularly limited, but for example, a non-aqueous electrolyte solution in which a lithium salt is dissolved in an organic solvent can be used as an electrolyte generally used in a lithium ion secondary battery. .

  In one example, the outer package 5 has a two-sheet structure of one laminate film disposed on the lower surface side of the power generation element 4 in FIG. 2 and another laminate film disposed on the upper surface side. The four sides around the two laminate films are superposed and heat-sealed to each other. The pair of terminals 2 and 3 positioned on the short side of the rectangular film-clad battery 1 are drawn out through the bonding surface of the laminate film when the laminate film is heat-sealed. In the illustrated example, a pair of terminals 2 and 3 are arranged side by side on the same edge, but the positive terminal 2 is arranged on one edge and the negative terminal 3 is arranged on the other edge. It is also possible to do so.

  As a manufacturing procedure of said film-clad battery 1, it is as follows. First, the power generation element 4 is configured by sequentially laminating the positive electrode plate 7, the negative electrode plate 8, and the separator 6 and attaching the terminals 2 and 3 by spot welding or the like. Next, the power generating element 4 is covered with a laminate film that becomes the outer package 5, and the surrounding four sides are heat-sealed leaving a relatively small filling port. Next, the exterior body 5 is filled with the electrolytic solution through the filling port, and then the filling port is heat-sealed to make the exterior body 5 sealed. Thus, the film-clad battery 1 is completed. Next, the battery is charged to an appropriate level, and in this state, aging is performed for a predetermined time. After this aging is completed, the battery is charged again for voltage inspection and shipped.

  Referring to FIG. 2, negative electrode active material layer 8b is longer in the longitudinal direction than positive electrode active material layer 7b so that lithium ions released from positive electrode active material layer 7b during charging are smoothly occluded in negative electrode active material layer 8b. It is set long. Accordingly, a part of the negative electrode active material layer 8 b faces the portion where the positive electrode active material layer 7 b is not coated, that is, the portion 7 c where the metal foil 7 a of the positive electrode plate 7 is exposed, with the separator 6 interposed therebetween. Thus, if a short circuit occurs between the negative electrode active material layer 8b facing each other and the portion 7c where the metal foil 7a of the positive electrode is exposed, it is more than the short circuit at the portion where the active material layers 7b and 8b face each other. There is a problem that current flows.

  Therefore, in this embodiment, the insulating tape 11 having a predetermined width made of synthetic resin such as polypropylene (PP) is pasted on both surfaces of the portion 7c where the metal foil 7a of the positive electrode plate 7 is exposed. Prevents short circuit.

  Next, with reference to FIGS. 3 to 5, a slitting method and a slitter device for the composite material 12 which are the main part of the present embodiment will be described. The sheet-shaped composite material 12 before cutting is configured by attaching insulating tapes 11 to both surfaces of the positive electrode plate 7 along the width direction P2. By cutting this composite material 12 along the longitudinal direction (vertical direction in FIG. 5) with a slitter device, a composite material main body 13 having a predetermined width according to the width direction dimension of the positive electrode plate 7, and a narrow scrap 14 , Separated. 3 to 5, a single composite material main body 13 is simply drawn, but actually, one composite material 12 to a plurality of composite material main bodies 13 and two on both sides in the width direction P <b> 2. Sheets of scrap 14 are obtained. Next, the positive electrode plate 7 having a predetermined rectangular shape is obtained by cutting the band-shaped composite material body 13 after being cut by another process (not shown) at predetermined intervals in the longitudinal direction according to the length of the positive electrode plate 7. Will be obtained.

  In this way, by cutting the composite material 12 with the insulating tape 11 attached to the positive electrode plate 7 along the longitudinal direction P1, as compared with the case where the insulating tape 11 is applied later after the positive electrode plate 7 is cut. Since both the insulating tape 11 and the positive electrode plate 7 can be cut simultaneously, the working efficiency is excellent, and the width direction dimensions of the both 11 and 7 can be made to coincide with each other with high accuracy.

  As shown in FIG. 3, in the present embodiment, in the cutting process, the first cutting part 15 and the second cutting part 16 are provided at two places in the delivery direction P1 of the composite material 12 along the longitudinal direction. The first cutting portion 15 provided on the upstream side in the delivery direction P1 is similar to that of the above-mentioned Japanese Patent Application Laid-Open No. 2008-279537, and the composite material 12 is sandwiched between the upper blade and the lower blade and the shearing force from both sides is used. 12 is sheared along the cutting line L1 in the longitudinal direction. The first cutting part 15 is suitable for cutting the positive electrode plate 7 containing metal. However, it is not suitable for cutting the insulating tape 11 made of synthetic resin. That is, since the insulating tape 11 is made of synthetic resin and is extensible, it extends in the shearing direction at the time of cutting and is cut by the first cutting portion 15. It may not be cut well.

  In this case, there are the following problems. Among the composite material 12, the composite material main body 13 which finally becomes the plurality of positive electrode plates 7 is wound along the delivery direction P1 directed vertically upward by the winder 17 disposed on the upstream side, The narrow scrap 14 that is not used as the positive electrode plate 7 falls down by its own weight without being wound, and is discarded. However, when the insulating tape 11 is not cut by the first cutting part 15, the scrap 14 is sent to the winder 17 side without being separated from the adjacent composite body 13 by the insulating tape 11, and the composite material There is a risk of hindering winding of the main body 13.

  Therefore, in the present embodiment, the second cutting portion 16 that cuts only the insulating tape 11 left without being cut by the first cutting portion 15 at a position separated by a predetermined distance downstream from the first cutting portion 15 is provided. Provided. Unlike the 1st cutting part 15 which shears so that this 2nd cutting part 16 may be pinched | interposed with an upper blade and a lower blade, it cuts so that it may cut | disconnect with the cutter blade 18 of sheets, and the insulating tape 11 made from a synthetic resin It is suitable for cutting.

  As shown in FIG. 3, when the insulating tape 11 is left without being cut, the scrap 14 above the insulating tape 11 hangs downward due to its own weight. A predetermined tension is applied in the width direction P2 to extend. Here, the cutter blade 18 of the second cutting portion 16 is disposed at a position closer to the scrap than the cutting line L1 by the first cutting portion 15 with respect to the width direction P2, that is, a position separated by a predetermined distance ΔD on the left side in FIG. Has been. Therefore, as shown in FIG. 3, only the extended portion of the insulating tape 11 can be easily cut by the cutter blade 18, and the cutter blade 18 does not interfere with the composite material main body 13, and the composite material main body 13 is mistaken. Will not hurt you. In particular, the edge of the composite material body 13 cut along the cutting line L1 by the first cutting part 15 is strictly controlled in size, and the second cutting part 16 may interfere with this edge. Therefore, the product quality is not deteriorated.

  Further, by cutting the insulating tape 11 at a position separated from the composite material body 13 in this way, immediately after the cutting, the insulating tape 11 protrudes from the edge of the composite material body 13 by the distance ΔD. Since the insulating tape 11 is in a state of extending in the width direction P2, the insulating tape 11 slightly shrinks toward the edge of the composite body 13 after cutting, so that the insulating tape 11 extends from the edge of the composite body 13. There is no significant shift.

  The structure of the second cutting part 16 will be described in more detail with reference to FIGS. 4 and 5. The second cutting portion 16 is roughly constituted by a housing 20 that holds the cutter blade 18. The housing 20 is provided with a guide member 21 along the composite material 12 delivered in the delivery direction P1. The guide member 21 has a guide surface portion 22 that is opposed to the composite material 12 that is sent out in the sending direction P1 with a slight gap, and the upstream side of the guide surface portion 22 in the sending direction P1 is directed toward the upstream side. A tapered surface portion 23 is provided so as to be gradually separated from the composite material 12. The guide member 21 having the guide surface portion 22 and the tapered surface portion 23 suppresses the flapping of the composite material 12 in the direction orthogonal to the main surface.

  A stopper wall portion 24 that stands vertically from the guide surface portion 22 is provided at the downstream end portion of the guide surface portion 22 located on the downstream side of the cutter blade 18 so as to face the position where the scrap 14 is fed out. It has been. By scraping the scrap 14 cut by the cutter blade 18 against the stopper wall portion 24, the scrap 14 is surely separated from the composite body 13 and hangs downward. That is, the stopper wall portion 24 functions as a stopper that prevents the scrap 14 from being sent out together with the composite material main body 13 in the sending direction P1.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes. For example, although the cutter blade 18 is used for the second cutting portion 16 in the above embodiment, other types of blades may be used. Further, the housing structure for supporting the cutter blade 18 is not limited to that shown in FIGS. 4 and 5, and may have another structure.

7 ... Positive electrode plate (electrode)
7a ... Positive electrode current collector (metal foil)
7b ... positive electrode active material layer (active material layer)
8 ... Negative electrode (electrode)
8a ... Negative electrode current collector (metal foil)
8b ... negative electrode active material layer (active material layer)
DESCRIPTION OF SYMBOLS 11 ... Insulating tape 12 ... Composite material 13 ... Composite material main body 14 ... Scrap 15 ... 1st cutting part 16 ... 2nd cutting part 18 ... Cutter blade 24 ... Stopper wall part (stopper)

Claims (6)

A process of producing a composite material by affixing an insulating tape of a predetermined width made of synthetic resin having insulation along an electrode formed with an active material layer on a metal foil along a width direction orthogonal to the longitudinal direction of the electrode; ,
Cutting the composite material along the longitudinal direction,
In the cutting step, the first cutting portion that cuts the composite material fed along the longitudinal direction at a predetermined position, and the first cutting portion at a position downstream of the first cutting portion in the delivery direction of the composite material. And a second cutting section for cutting the insulating tape left without being cut by the cutting section. The composite material is separated into a composite material main body and scrap by the first cutting part,
The method for slitting a composite material according to claim 21, wherein the second cutting portion cuts the insulating tape at a position closer to the scrap than a cutting line by the first cutting portion in the width direction. .   33. The method for slitting a composite material according to claim 32, wherein the delivery direction is directed upward in the vertical direction.   4. The stopper according to claim 1, further comprising a stopper that interferes with the scrap and prevents the scrap from being sent out in the feeding direction together with the composite material body on the downstream side in the feeding direction of the second cutting portion. The slit method of the composite material as described in 1. The electrode is a positive electrode plate;
The method for slitting a composite material according to any one of claims 1 to 4, wherein the insulating tape is attached to a portion of the positive electrode plate that is not coated with a positive electrode active material layer. For the electrode in which the active material layer is formed on the metal foil, a composite material in which an insulating tape having a predetermined width made of a synthetic resin having an insulating property is attached along the width direction orthogonal to the longitudinal direction of the electrode A slitting device for a composite material that cuts along a direction,
A first cutting section for cutting the composite material fed along the longitudinal direction at a predetermined position;
A second cutting section that cuts the insulating tape left uncut by the first cutting section at a position downstream of the first cutting section in the delivery direction of the composite material. A slitting device for composite materials.

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