JP6396961B2 - Sheet material cutting method - Google Patents

Description

  The present invention relates to a technique for cutting a sheet material made of paper or synthetic resin used for a separator for a non-aqueous electrolyte secondary battery or the like with a laser beam.

  As a method of cutting a sheet material used for a non-aqueous electrolyte secondary battery separator into a predetermined size, a mechanical cutting method using a blade called a guillotine blade has been conventionally employed. However, in this cutting method, since the blade is in contact with the sheet material during the cutting operation, as the cutting operation is repeated, a part of the content of the sheet material is attached to the blade and accumulates, and the sharpness deteriorates. Or roughened cut parts. For this reason, every time the cutting operation is performed for a predetermined time (or each time the cutting operation is performed a predetermined number of times), the cutting operation must be stopped, the blades must be cleaned to remove the deposits, and work efficiency is reduced.

  On the other hand, various cutting techniques using laser light have been proposed as cutting methods that do not use a blade (see, for example, Patent Documents 1 to 5).

JP 2011-96620 A JP 2011-5522 A JP 2010-53310 A JP 2007-299551 A JP-A-6-267526

  As described above, in the case of a cutting technique using a cutting tool, there is a problem that work efficiency is lowered because periodic cleaning is required. On the other hand, since the cutting method using the laser beam described in Patent Documents 1 to 5 does not use a blade, it is not necessary to clean the blade regularly.

  However, when a sheet material used for a separator for a non-aqueous electrolyte secondary battery is cut with a laser beam, the cut portion of the sheet material is altered or deformed by the thermal energy of the irradiated laser beam. In many cases, some of the contained components are dropped off, and the required cutting performance is not obtained.

  Therefore, the problem to be solved by the present invention is that the cutting portion of the sheet material that is the object to be cut does not change or deform, the contained component of the sheet material does not fall off, and the cutting speed of the sheet material is high. It is to provide a method.

  The sheet material cutting method of the present invention is a sheet material cutting method used for a separator for a non-aqueous electrolyte secondary battery, wherein the sheet material is placed on a substrate having a slit, and the sheet material is cut Is held in close contact with the substrate by the relaxation preventing means, and the sheet material is irradiated with a laser beam that scans along the slit.

  With such a configuration, it is possible to irradiate the laser beam in a state where the sheet material to be cut is stably held on the substrate, and the laser beam irradiated to the sheet material passes through the slit. No adverse effects due to reflection (for example, a phenomenon in which the inclusion of the sheet material adheres to the substrate due to the heat effect from the substrate) does not occur, and the output of the laser beam, the scanning speed, etc. according to the material and thickness of the sheet material By appropriately setting the sheet material, it is possible to quickly cut the sheet material without causing alteration / deformation of the cut portion and dropping off of the contained components.

  Further, the sheet material cutting method of the present invention is a sheet material cutting method used for a separator for a non-aqueous electrolyte secondary battery, wherein the sheet material is formed on a substrate formed of a material having laser light absorption. The sheet material is held in close contact with the substrate by means of an anti-relaxation means, and is irradiated with laser light that scans in the surface direction of the substrate toward the sheet material.

  With such a configuration, similarly to the above, the laser beam can be irradiated with the sheet material to be cut stably held on the substrate, and the laser beam irradiated on the sheet material is absorbed by the substrate. In addition, since no adverse effects due to the reflection of the laser beam occur, by appropriately setting the laser beam output, the scanning speed, etc. according to the material and thickness of the sheet material, it is possible to alter or deform the cut part, The sheet material can be quickly cut without dropping off. Note that carbon, POM (polyacetal), and the like are preferable as the material having laser light absorptivity.

  Here, it is desirable to spray an inert gas in a direction in which the sheet material is pressed against the substrate in the laser light irradiation region.

  With such a configuration, the inert gas blown to the irradiation region of the laser light increases the adhesion between the sheet material and the substrate, and the air in the vicinity of the cut portion of the sheet material can be excluded. It is possible to effectively prevent alteration and deformation of the resulting cut portion.

  Further, a magnet that can be attracted to the substrate can be used as the relaxation preventing means. With such a configuration, the sheet material can be stably held by a simple operation of placing a magnet on the upper surface of the sheet material on the substrate, and can be easily detached from the sheet material.

  On the other hand, a plurality of the sheet materials can be stacked and placed on the substrate. With such a configuration, since a plurality of sheet materials can be cut simultaneously, the efficiency of the cutting work can be increased.

  As the laser beam, a carbon dioxide laser beam having an output of 1 W to 100 W or a YAG laser beam having an output of 1 W to 42 W can be used. With such a configuration, a sheet material made of synthetic resin having a thickness of about 5 μm to 80 μm can be quickly cut without being altered or deformed.

  The laser beam scanning method may be a galvano method or a spot method. When the object to be cut is a sheet material, the galvano type performs cutting by scanning the laser beam by mirror-reflecting the laser beam, so an XY table for moving the object to be cut is unnecessary, and the cutting is performed. The device can be simplified and the price can be reduced. On the other hand, in the spot type, cutting is performed by scanning the laser beam by moving the beam bender in the XY direction, so that a wide cutting processing range can be secured.

  According to the present invention, it is possible to provide a sheet material cutting method with a high cutting speed, in which a cut portion of a sheet material that is an object to be cut is not altered or deformed or components contained in the sheet material are not dropped.

It is a partially-omission front view which shows the laser cutting device used for the sheet material cutting method which is embodiment of this invention. It is a partially expanded sectional view of FIG. It is a partially-omission sectional view which shows the other use condition of the laser cutting device shown in FIG.

  First, a sheet material used for a separator for a nonaqueous electrolyte secondary battery, which is a first object to be cut in the sheet material cutting method of the present embodiment, will be described. A sheet material used for a separator for a non-aqueous electrolyte secondary battery (hereinafter sometimes referred to as “separator”) is a porous film (hereinafter referred to as “A membrane”) containing a water-soluble polymer and fine particles. And a polyolefin porous membrane (hereinafter sometimes referred to as “B membrane”), and a slurry liquid containing a water-soluble polymer, fine particles, and a medium is made into a porous polyolefin. It can be manufactured by applying to a film (B film) and removing the medium by drying or the like.

  The A film has heat resistance at a high temperature at which shutdown occurs, and imparts a shape stability function to the separator. In addition, the B film melts and becomes non-porous in the event of abnormal heat generation in the event of a battery accident, thereby providing a shutdown function to the separator. The A film and the B film may be three or more layers as long as they are sequentially laminated. For example, the form etc. with which A film | membrane was formed on both surfaces of B layer are mentioned.

  Shutdown refers to preventing further heat generation by blocking the passage of ions between the positive electrode and negative electrode in the event of abnormal heat generation due to an accident or the like, and a method of providing a separator with a shutdown function is common. . As a method for providing the separator with a shutdown function, a method in which a porous film made of a material that melts when abnormal heat is generated is used as the separator. That is, in the battery using the separator, the porous film melts and becomes non-porous when abnormal heat is generated, and the passage of ions can be blocked and further heat generation can be suppressed.

  The A film described above is a porous film of a water-soluble polymer containing fine particles, and examples of the water-soluble polymer include polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, and polymethacrylic acid. Cellulose ether, polyvinyl alcohol, and sodium alginate are preferable, and cellulose ether is more preferable. Specific examples of the cellulose ether include carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), carboxyethyl cellulose, methyl cellulose, ethyl cellulose, cyanethyl cellulose, oxyethyl cellulose, and the like. preferable.

  As the fine particles, inorganic or organic fine particles generally called fillers can be used. Specifically, styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, methyl acrylate, or a copolymer of two or more kinds; polytetrafluoroethylene, tetrafluoroethylene-6 Fluorine resin such as fluorinated propylene copolymer, tetrafluoroethylene-ethylene copolymer, polyvinylidene fluoride, etc .; melamine resin; urea resin; polyethylene; polypropylene; fine particles made of organic matter such as polymethacrylate. Also, calcium carbonate, talc, clay, kaolin, silica, hydrotalcite, diatomaceous earth, magnesium carbonate, barium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, aluminum hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, titanium oxide , Fine particles composed of inorganic substances such as alumina, mica, zeolite, glass and the like. Among these, alumina is desirable as the fine particles. These fine particle materials can be used alone or in admixture of two or more.

The fine particles constituting the A film together with the water-soluble polymer are fine particles (a) having an average particle size of less than 0.1 μm and a specific surface area of 50 m ² / g or more, and fine particles having an average particle size of 0.2 μm or more. It is preferable that the weight ratio of the fine particles (a) and the fine particles (b) is 1: 0.05 to 50. In addition, the kind of microparticles | fine-particles (a) and microparticles | fine-particles (b) may be the same, and may differ.

  Of the two types of fine particles, the fine particles (b) having a large particle size contribute to the shape stability of the A film at a high temperature as the main skeleton of the A film. The fine particles (a) having a small particle size have an effect of filling the gaps between the fine particles (b) to further increase the mechanical strength of the A film. Further, as described later, it also has an action of suppressing excessive penetration of the water-soluble polymer into the B membrane pores when the separator of the present invention is produced.

  The A film needs to contain both two kinds of fine particles, fine particles (a) and fine particles (b). When only one of the fine particles (a) and the fine particles (b) is used, the shape stability at a high temperature at a practical level and the shutdown property are simultaneously maintained while maintaining sufficient air permeability (ion permeability). I can't.

The fine particles (a) are required to have an average particle diameter of less than 0.1 μm, preferably less than 0.05 μm, and the specific surface area of the fine particles (a) is 50 m ² / g or more. Is preferably 70 m ² / g or more. Examples of the shape of the fine particles (a) include a spherical shape and a bowl shape. Here, the specific surface area of the fine particles (a) is a value measured by the BET measurement method. Further, the average particle diameter d (μm) of the fine particles (a) is calculated based on the formula “average particle diameter d (μm) based on the BET specific surface area B (m ² / g) and the true density D (g / m ³ ) of the fine particles. ) = 6 / (B × D) ”.

If the fine particles (a) do not satisfy the average particle size of less than 0.1 μm and the specific surface area of 50 m ² / g or more at the same time, the formation of the A film becomes unstable, and the B film pores of the water-soluble polymer during the production of the separator Excessive penetration into the inside cannot be suppressed, and the shutdown performance (non-porous B film) of the separator becomes insufficient.

On the other hand, the fine particles (b) are required to have an average particle size of 0.2 μm or more, and preferably 0.25 μm or more. When the average particle size of the fine particles (b) is less than 0.2 μm, the shrinkage during heating of the A film cannot be sufficiently suppressed, and the shape stability at high temperature becomes insufficient. The specific surface area of the fine particles (b) is not particularly limited, but is preferably 20 m ² / g or less, particularly preferably 10 m ² / g or less. Examples of the shape of the fine particles (b) include a spherical shape and a bowl shape.

  The average particle size of the fine particles (b) is 25 particles by arbitrarily extracting 25 particles with a scanning electron microscope (SEM) and measuring the particle size (diameter) of each particle. It is a value calculated as an average value of. Further, when the shape of the fine particles (b) is other than a spherical shape, the length in the direction showing the maximum length of the particles is the particle size. The specific surface area of the fine particles (b) is a value measured by the BET measurement method.

  In the A film, the weight ratio of the fine particles (a) to the fine particles (b) (the ratio of the fine particles (b) when the fine particles (a) is 1) is 1: 0.05 to 50. Necessary, preferably 1: 0.1-15, particularly preferably 1: 0.2-10.

  If the weight ratio is less than 0.05, the thermal contraction of the A film cannot be sufficiently suppressed, and the shape stability at high temperature becomes insufficient. If it exceeds 50, the water-soluble polymer enters the pores of the B film. Excessive penetration will impair the shutdown performance of the separator.

  In addition, fine particles other than the fine particles (a) and the fine particles (b) (hereinafter, may be referred to as “other fine particles”) may be included within the range not impairing the above-described effects. The content of the other fine particles in the A film is preferably 100% by weight or less, and 50% by weight or less (including 0% by weight) with respect to the total of the fine particles (a) and (b). It is more preferable.

  The thickness of the A film is usually 0.1 μm or more and 20 μm or less, preferably 2 μm or more and 15 μm or less. If it is too thick, the load characteristics of the battery may be reduced when a non-aqueous electrolyte secondary battery is manufactured. If it is too thin, the polyolefin porous membrane may be damaged when the battery generates heat due to an accident or the like. There is a risk that the separator may shrink without resisting heat shrinkage. When the A film is formed on both surfaces of the B film, the thickness of the A film is the total thickness of both surfaces.

  The A film is a porous film, and the pore diameter is preferably 3 μm or less, more preferably 1 μm or less, as the diameter of the sphere when the hole is approximated to a sphere. When the average pore size or the pore size exceeds 3 μm, there is a possibility that a problem such as short-circuiting easily occurs when the carbon powder or the small piece as the main component of the positive electrode or the negative electrode is dropped. Further, the porosity of the A film is preferably 30 to 90% by volume, more preferably 40 to 85% by volume.

Next, the B film constituting the separator described above will be described. The B film is a polyolefin porous film and does not dissolve in the electrolyte solution in the non-aqueous secondary battery. It is preferable that a high molecular weight component having a weight average molecular weight of 5 × 10 ⁵ to 15 × 10 ⁶ is contained. Examples of the polyolefin include a high molecular weight homopolymer or copolymer obtained by polymerizing ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and the like. Among these, high molecular weight polyethylene mainly composed of ethylene is preferable.

  The porosity of the B film is preferably 20 to 80% by volume, more preferably 30 to 70% by volume. If the porosity is less than 20% by volume, the amount of electrolyte retained may be small, and if it exceeds 80% by volume, non-porous formation at a high temperature causing shutdown will be insufficient, that is, when the battery generates heat due to an accident. The current may not be cut off.

  Moreover, the thickness of B film | membrane is 4-50 micrometers normally, Preferably it is 5-30 micrometers. If the thickness is less than 4 μm, the shutdown may be insufficient, and if it exceeds 50 μm, the thickness of the separator for a nonaqueous electrolyte secondary battery including the water-soluble polymer porous layer increases, and the electric capacity of the battery May decrease. The pore size of the B film is preferably 3 μm or less, and more preferably 1 μm or less.

  The B film has a structure having pores connected to the inside thereof, and gas or liquid can pass from one surface to the other surface. The air permeability is usually in the range of 50 to 400 seconds / 100 cc in terms of Gurley value, and preferably in the range of 50 to 300 seconds / 100 cc.

  In the separator composed of the A film and the B film described above, the A film and the B film are laminated to constitute the separator. A film body other than the A film and the B film, for example, a porous film such as an adhesive film or a protective film may be included in the separator as long as the purpose is not impaired.

  The thickness of the whole separator (A film + B film) is usually 5 to 80 μm, preferably 5 to 50 μm, particularly preferably 6 to 35 μm. If the total thickness of the separator is less than 5 μm, the membrane is likely to break, and the thickness of the separator for a non-aqueous electrolyte secondary battery including the water-soluble polymer porous layer is increased, which may reduce the electric capacity of the battery. Moreover, the porosity of the whole separator is 30-85 volume% normally, Preferably it is 35-80 volume%.

  Moreover, when a non-aqueous secondary battery is manufactured using the separator, high load characteristics can be obtained, but the air permeability of the separator is preferably 50 to 2000 seconds / 100 cc, and more preferably 50 to 1000 seconds / 100 cc. If the air permeability is 2000 seconds / 100 cc or more, the ion permeability of the separator and the load characteristics of the battery may be lowered.

  As the dimension retention rate of the separator at a high temperature at which shutdown occurs, the smaller value of the B film in the MD direction or TD direction is 90% or more, preferably 95% or more. Here, the MD direction refers to the long direction during sheet forming, and the TD direction refers to the width direction during sheet forming. If the dimensional maintenance ratio is less than 90%, a short circuit may occur between the positive electrode and the negative electrode due to thermal contraction of the separator at a high temperature at which shutdown occurs, and as a result, the shutdown function may be insufficient. Note that the high temperature at which shutdown occurs is a temperature of 80 to 180 ° C., and usually about 130 to 150 ° C.

  When a non-aqueous electrolyte secondary battery is manufactured using the separator for a non-aqueous electrolyte secondary battery described above, the separator exhibits a shutdown function even when the battery has a severe heat generation due to an accident, Contact between the positive electrode and the negative electrode due to shrinkage of the separator is avoided, and a highly safe non-aqueous electrolyte secondary battery is obtained.

  Next, the sheet material which performed the corona treatment which is the 2nd to-be-cut object in the sheet material cutting method of this embodiment is demonstrated in detail. In the separator manufacturing process, the sheet material subjected to corona treatment is subjected to corona treatment, which is one of the hydrophilic treatments, on the B film before applying the slurry liquid onto the B film. A slurry liquid for forming an A film containing a conductive polymer, fine particles (a) and (b) and a medium is applied on the B film, and then the medium is removed.

  Here, the corona treatment means that corona discharge is generated by a high frequency / high voltage output supplied from a high frequency power source, a B film (polyolefin porous film) is passed through the corona discharge, and the B film is irradiated with the corona discharge. This is a treatment for modifying (hydrophilizing) the surface of the B film.

  By subjecting the B film to corona treatment, the coating property of the slurry liquid is improved, and a more uniform porous film (A film) can be obtained. Corona treatment is more effective especially when the concentration of the solvent in the medium is low. By performing corona treatment, the B membrane can be hydrophilized in a relatively short time, and the modification of the polyolefin resin by corona discharge is limited only to the vicinity of the surface of the B membrane, and the pores of the B membrane are hydrophobic. There is an advantage that only the vicinity of the surface of the B film can be hydrophilized while maintaining.

  For this reason, when the slurry liquid is applied, excessive entry of the slurry liquid containing the water-soluble polymer into the pores (voids) of the B film can be suppressed, and the shutdown performance of the B film is impaired by the water-soluble polymer precipitation. You can avoid that. As the hydrophilic treatment of the B film, in addition to the corona treatment described above, a chemical treatment using an acid or an alkali, a plasma treatment, or the like can be employed.

Hereinafter, based on FIGS. 1-3, the sheet | seat material cutting method which is embodiment of this invention is demonstrated. As shown in FIGS. 1 and 2, the spot type carbon dioxide laser cutting device LA includes a substrate 10 on which the sheet material 20 as the first object to be cut is placed, and a carbon dioxide laser oscillation unit (not shown). A beam bender 11 incorporating a mirror (not shown) that bends the laser beam LB emitted in the vertical direction, an XY table 14 that moves the beam bender 11 in the horizontal direction, and a sheet of the laser beam LB. a lens 12 for condensing on the wood 20, toward the irradiation area of the laser beam LB, and includes an air supply path 13 for blowing nitrogen gas N ₂ is assist gas.

  A slit 15 is formed in the substrate 10. When the beam bender 11 is moved in the longitudinal direction of the slit 15 by operating the XY table 14, the laser beam LB scans along the slit 15. Further, as a loosening prevention means for holding the sheet material 20 in close contact with the substrate 10, a sheet-like magnet 16 that is attracted to the substrate 10 is disposed on the sheet material 20 so as to face each other across the slit 15. .

As shown in FIG. 3, a nozzle 17 having a shape that reduces the diameter along the condensing direction of the laser beam LB can be attached to the tip opening 11 a of the beam bender 11. With such a configuration, the nitrogen gas N ₂ supplied from the air supply path 13 is throttled in the nozzle 17, and intensively moves from the tip opening 17 a toward the irradiation region of the laser beam LB with the flow velocity increased. And blown out.

  Here, the sheet material 20 is divided into three types of laser cutting devices, that is, a carbon dioxide laser cutting device LA, a galvano type carbon dioxide laser cutting device GB (not shown) and a galvano type YAG fiber laser cutting device GC shown in FIG. Since the experiment which evaluates the quality of the cut cross section by cutting using (not shown) was performed, the result is demonstrated based on Table 1. FIG.

  The sheet material 20 is a separator for a non-aqueous electrolyte secondary battery (thickness: 5 to 80 μm), which is a laminate of a water-soluble polymer porous film containing fine particles and a polyolefin porous film, which is the first object to be cut. As the evaluation criteria for the cut cross section of the sheet material 20, the following four items are included: "whether the cross section is burnt", "whether the cross section is curled", "whether there is powder falling during cutting", and "cut speed". Set. Here, “the cross section is burnt” means that the vicinity of the cut cross section of the sheet material 20 is carbonized (blackened) and oxidized by heat, and “the occurrence of curling of the cross section” means that the vicinity of the cut cross section of the sheet material 20 is curved. Deformation or “powder off at the time of cutting” refers to a phenomenon in which fine particles (such as alumina) contained in the sheet material 20 fall off from the cut cross-section.

◎，○：良好 △：ＮＧ ＰＷ：パルス発振

◎, ○: Good △: NG PW: Pulse oscillation

  Sheet material 20 (non-aqueous electrolyte secondary battery separator formed by laminating a water-soluble polymer porous film containing fine particles and a polyolefin porous film) that has not been subjected to corona treatment is divided into three types of laser cutting devices LA, GB, As a result of cutting using GC, as shown in Table 1, using a spot-type carbon dioxide laser cutting device LA, laser cutting is performed under conditions of 3 W output, cutting speed of 80 m / min, nitrogen gas as assist gas, and no substrate. When cut, there is no powder falling off at the time of cutting, and it can be seen that the state of the cut section is the best.

Further, when the results shown in Table 1 are seen, all of the cutting devices LA, GB, and GC can perform laser cutting of the sheet material 20, but the carbon dioxide laser cutting device LA and the galvano type carbon dioxide laser cutting device GB are cutting. Since the speed is fast, it is the most effective, and the galvano type YAG fiber laser cutting device GC is unsuitable because the cutting speed is slow. Furthermore, it can be seen that the spot diameter of the laser beam is desirably 100 μm or less in order to prevent the occurrence of curling of the cross section and powder falling off during cutting. On the other hand, although not described in Table 1, it is possible to cut the laser beam with a spot diameter of 100 μm or more (for example, about 200 μm), but the area of the cut portion becomes large, and the occurrence of curling and cutting of the cross section occurs. There was a tendency for the powder to fall off easily. The theoretical value of the spot diameter of the laser beam can be obtained based on the following calculation formula.
d = 4λfM2 / (πD)
However, d is the spot diameter at the workpiece position, D is the spot diameter before being focused by the lens (incident beam diameter), λ is the wavelength of the laser beam, f is the focal length (distance to the workpiece), and M2 is Msquare (beam Of light condensing property).

Next, a corona-treated sheet material (thickness 5 to 80 μm: not shown), that is, the above-described second object to be cut, that is, a water-soluble polymer porous film containing fine particles and a polyolefin porous film A laminated sheet of non-aqueous electrolyte secondary battery separator in which corona treatment of a polyolefin porous membrane is used to perform a cutting experiment using three types of laser cutting devices LA, GC, and GD. To do. The laser cutting devices LA and GC are the same as the laser cutting devices LA and GC shown in Table 1, but the laser cutting device GD is a galvano green (YVO ₄ ) laser cutting device.

◎，○：良好 △：ＮＧ ＰＷ：パルス発振

◎, ○: Good △: NG PW: Pulse oscillation

  Corona-treated sheet material (separator for nonaqueous electrolyte secondary battery in which a water-soluble polymer porous membrane containing fine particles and a polyolefin porous membrane are laminated) is divided into three types of laser cutting devices LA, GC, GD. As shown in Table 2, when galvano-type YAG fiber laser cutting device GC was used, laser cutting was performed under the conditions of an output of 4.8 W, a cutting speed of 9 m / min, no assist gas, and no substrate. It can be seen that the state of the cut cross section is the best without any powder falling off during cutting.

  Moreover, when the result shown in Table 2 is seen, the laser beam absorptivity of a sheet material will improve by performing a corona treatment, and it cut | disconnects with the laser beam of output smaller than the case where the sheet material which has not performed the corona treatment is cut | disconnected. You can see that you can. Further, in the cutting using the galvano-type YAG fiber laser cutting device GC, when cutting a sheet material subjected to corona treatment, three times as much as cutting a sheet material not subjected to corona treatment. It can be seen that the speed can be increased. Furthermore, it can be seen that the spot diameter of the laser beam is desirably 100 μm or less in order to prevent the occurrence of curling of the cross section and powder falling off during cutting. On the other hand, although not described in Table 2, although it is possible to cut the laser beam with a spot diameter of 100 μm or more (for example, about 200 μm), the area of the cut portion becomes large, and the occurrence of curling and cutting of the cross section occurs. There was a tendency for the powder to fall off easily.

  The above-described embodiment shows an example of the present invention, and the laser cutting method according to the present invention is not limited to the above-described embodiment.

  The sheet material cutting method of the present invention can be widely used in fields such as the electrical / electronic equipment industry and the automobile industry as a method for cutting various sheet materials such as a separator for a non-aqueous electrolyte secondary battery.

DESCRIPTION OF SYMBOLS 10 Board | substrate 11 Beam bender 11a, 17a Opening part 12 Lens 13 Air supply path 14 XY table 15 Slit 16 Sheet-like magnet 17 Nozzle 20 Sheet material LA Laser cutting device LB Laser beam N ₂ Nitrogen gas

Claims (11)

A method of cutting a sheet material used for a separator for a non-aqueous electrolyte secondary battery,
The sheet material is placed on a substrate having a slit, the sheet material is held in close contact with the substrate by a loosening prevention unit, and the spot diameter scanned along the slit with respect to the sheet material is A sheet material cutting method characterized by irradiating a laser beam of 100 μm or less. A method of cutting a sheet material used for a separator for a non-aqueous electrolyte secondary battery,
The sheet material is placed on a substrate formed of a material having a laser light absorption property, the sheet material is held in close contact with the substrate by a loosening prevention unit, and the surface of the substrate with respect to the sheet material A method for cutting a sheet material, which comprises irradiating a laser beam having a spot diameter scanned in the direction of 100 μm or less.   The sheet material cutting method according to claim 2, wherein the substrate is formed of carbon or POM (polyacetal).   The sheet material cutting method according to claim 1, wherein the sheet material is a corona-treated sheet material. A method of cutting a sheet material used for a separator for a non-aqueous electrolyte secondary battery,
The sheet material is a corona-treated sheet material,
The sheet material is placed on a substrate having a slit, the sheet material is held in close contact with the substrate by means of relaxation prevention, and laser light that scans along the slit is scanned with respect to the sheet material. Irradiating, the sheet | seat material cutting method characterized by the above-mentioned. A method of cutting a sheet material used for a separator for a non-aqueous electrolyte secondary battery,
The sheet material is a corona-treated sheet material,
The sheet material is placed on a substrate formed of a material having a laser light absorption property, the sheet material is held in close contact with the substrate by a loosening prevention unit, and the surface of the substrate with respect to the sheet material A method for cutting a sheet material, characterized by irradiating laser light that scans in a direction. Sheet material cutting method of the material according to claim 6, wherein the carbon or POM (polyacetal) that has the laser-absorbing.   The sheet material cutting method according to claim 1, wherein a magnet that can be attracted to the substrate is used as the relaxation preventing means.   The sheet | seat material cutting method in any one of Claims 1-8 which piles up and mounts the said several sheet | seat material on the said board | substrate.   The sheet material cutting method according to any one of claims 1 to 9, wherein the laser beam is a carbon dioxide laser beam having an output of 1W to 100W or a YAG laser beam having an output of 1W to 42W.   The sheet material cutting method according to claim 1, wherein the laser beam scanning method is a galvano method or a spot method.

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