JPH11167916A - Manufacture of electrode plate for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance bulk density of a mixed layer part, and to improve battery capacity by partially exposing a metallic foil current collector through removal of an electrode mixed layer of an electrode plate with the use of a rotating cutting tool. SOLUTION: A metallic foil current collection is partially exposed by removing an electrode mixed layer to install a lead to electrically connect an electrode plate and an external load on the electrode plate and/or to avoid stress concentration on a bending part, when the electrode plate is formed as a bending structure. At this time, a rotating cutting tool which is capable of cutting not only in the thickness direction of the electrode mixed layer but also in the surface direction is used to the electrode plate, but among them, an end mill and a shaft-possessing grinding wheel are suitably used. According to this, the metallic foil current collector is not damaged, the electrode mixed layer is chipped off, nor processing of a solvent is required. Moreover, residue processing of a separated electrode mixed layer can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrode plate for a battery.

[0002]

2. Description of the Related Art A battery is formed by spirally winding an electrode plate composed of an electrode mixture layer mainly composed of an active material and a binder and a metal foil collector, or laminating the electrode plate as a flat plate. However, in order to function as a battery, it is necessary to attach a lead for electrically connecting the electrode plate and an external load to the electrode plate.

[0003] Until now, when an electrode mixture layer has been present on the entire surface of a metal foil current collector, the lead and the metal foil current collector are swaged across the electrode mixture layer without peeling the electrode mixture layer. Bonding or scraping the electrode mixture layer using a scraper,
Generally, it is common to remove the electrode mixture layer partially by performing treatment such as peeling using ultrasonic vibration, and to weld or caulk the partially exposed metal current collector and lead. Was used.

However, when an electrode from which the electrode mixture layer has not been peeled off is joined by caulking the lead and the metal foil current collector with the electrode mixture layer interposed therebetween, the electrical connection between the lead and the metal foil current collector is established. However, it was not stable, resulting in an increase in the impedance inside the battery. Also, the electrode mixture layer on the metal foil current collector is scraped off using a scraper, peeled off using ultrasonic vibration, and the metal current collector and the lead are welded using a partially exposed electrode plate. Or, when connected by crimping, although the stability of the electrical connection is good and an electrode assembly without impedance rise can be obtained,
The metal foil current collector breaks due to mechanical stress at the time of peeling, the electrode plate becomes defective, or the electrode active material is chipped from the electrode mixture layer due to vibration, and chipping occurs The particles caused an internal short circuit in the battery.

In order to solve these problems, Japanese Patent Laid-Open Publication No.
Japanese Patent Publication No. 138655 proposes a method in which a portion to be peeled is wetted with a solvent in advance to facilitate the peeling. In this method, although the peeling is facilitated, the dimensional accuracy of the peeling range due to the wraparound of the solvent is proposed. Can not be secured, the battery capacity varies, and a solvent is used, so an exhaust device is required to improve the working environment, which not only increases the cost but also causes the peeled electrode mixture to be a paste. In some cases, these reattach to the electrode plate and cause the electrode plate to become defective, or the paste adheres to the device and soils the device. When a mask is used to secure the dimensional accuracy of the peeling range or to obtain a peeling range of an irregular shape, it is necessary to create a mask every time the peeling range changes, which requires man-hours for mask management. there were.

In the case where the electrode plate is formed by applying a slurry of a mixture of an active material, a binder and a solvent of a binder to a metal foil current collector and drying the same, for example, Japanese Patent Application Laid-Open No. As disclosed in JP-A-184069 and JP-A-8-131934, by using an intermittent coating method in which an electrode mixture layer is not provided in advance on a part of a metal foil current collector. A method of obtaining an exposed metal foil current collector area without peeling or scraping the electrode mixture layer as described above has also been adopted.

However, on a part of the metal foil current collector,
To perform intermittent coating without providing an electrode mixture layer,
Not only is a very special coating device required, but not only is it not possible to obtain an irregular shaped peeling area, but also when applying roll pressure after coating, the thickness difference between the coated and uncoated parts is large. In the uncoated part, the clearance between the rolls sharply narrowed, and as a result, the roll pinched the uncoated part, and the metal foil current collector could not withstand the winding tension, causing breakage. Was. In addition, the roll surface may be damaged by the collision between the rolls. To prevent this, if a wedge that secures the minimum value of the clearance between rolls is provided, breakage or damage to the roll will not occur, but the roll will idle due to a sharp decrease in the electrode plate feeding ability by the roll. In addition, the winding tension has been remarkably changed, and a problem has occurred that normal winding cannot be performed.

On the other hand, in order to cope with the recent miniaturization and thinning of portable equipment, batteries are also required to be small and thin. When a thin battery is formed, the spirally wound electrode coil may be crushed using a press and molded flat, but due to the springback phenomenon during molding, it is difficult to control the finished thickness, In order to reduce the thickness, a high-strength metal case that can withstand the deformation stress of the battery has been required. Further, since an electrolytic solution exists inside the battery, a metal case is preferable from the viewpoint of ensuring safety. However, due to the processing limit of the metal case, a battery having a thickness of at most about 5 mm was obtained.

On the other hand, in the case of a polymer battery which is expected to have a high energy density as a next-generation lithium ion secondary battery, a method of forming a battery by stacking flat electrodes is generally performed. Since no deformation occurs due to the fact that the system does not contain any substantial liquid, it is possible to use an aluminum-laminated polymer package, so that an ultrathin battery of 3 mm or less can be formed. For the purpose of increasing the capacity, proposals have been made such as a structure in which single-wafer electrodes are stacked, and a structure in which the electrodes have a folded structure in which mountain folds and valley folds are alternately repeated.

In both the laminated structure and the bent structure, the exposed metal foil current collector area for taking out the lead is necessary. Particularly, in the case of a sheet-shaped battery, the arbitrariness of the battery shape is limited. In order to increase the volume energy efficiency, it is expected that the electrodes also need to be shaped differently according to the battery shape, but in this case, the exposed metal foil current collector area for lead extraction is not necessarily rectangular. Not necessarily, an irregular area is needed.

In the conventional method of forming an uncoated portion at the time of coating, such as an intermittent coating method, it is impossible to form an unusually exposed metal current collector area as described above. In order to obtain an unusually exposed metal current collector area, a mold mask having a desired shape is used in Japanese Patent Application Laid-Open No. 8-13886.
Using the method disclosed in Japanese Patent Publication No. 55-55, an electrode obtained by a method in which a place to be peeled off is wetted in advance with a solvent and peeled off is used.

Japanese Patent Application Laid-Open No. 5-283107 discloses an electrode structure in which the electrode mixture layer at the bent portion is peeled off, and the electrode structure is easy to bend and has no distortion even at the valley fold portion. In order to exfoliate, the above-mentioned problems such as breakage of the metal foil current collector and chipping of the electrode mixture layer occur not only here, but also in this case, the exfoliation width is at most about 3 mm. It is practically impossible to use an intermittent application method that forms a stripe that does not have an electrode mixture layer on a part of the metal foil current collector at a required pitch in the coating direction. And Japanese Patent Laid-Open No. 7-9
The method can be dealt with only by a method of forming a stripe-shaped portion which is not coated at a required pitch in a direction perpendicular to the coating direction as exemplified in JP-A-4170 and JP-A-5-283107. there were.

However, a coating method of forming a stripe-shaped portion not coated at a required pitch in a direction perpendicular to the coating direction is a method of forming stripes intermittently at a required pitch in the coating direction. Although it is easier than it is, if the bending pitch changes, the coating head needs to be modified or the coating width is limited according to the size of the coating machine,
There is a problem that the number of layers of the bending lamination is limited. In addition, it was impossible in this case to obtain a peeled area having an irregular shape.

[0014]

SUMMARY OF THE INVENTION The present invention comprises an electrode mixture layer containing an active material and a binder as main components, and a metal foil current collector integrated with the electrode mixture layer. In a method of manufacturing a battery electrode plate in which a metal foil current collector is partially exposed by removing a part of the mixture layer, the electrode material mixture is not damaged without damaging the metal foil current collector. It does not cause chipping of the layer, does not require solvent treatment, and is easy to treat the separated electrode mixture layer scum. It is intended to provide a manufacturing method. Furthermore, it is possible to obtain a partially exposed metal foil current collector area having a width that is difficult with intermittent coating with high dimensional accuracy, and particularly when the shape of the area is changed, change the device jig. Instead, the present invention provides a method for manufacturing a battery electrode plate that can be performed by changing a program.

[0015]

That is, the present invention provides:
(1) The electrode mixture layer containing an active material and a binder as main components and an electrode plate composed of a metal foil current collector are removed by using a rotating cutting tool to remove the electrode mixture layer. A method of manufacturing a battery electrode plate, wherein the metal foil current collector is partially exposed, and (2) the electrode plate is formed of a mixture slurry of an active material, a binder, and a solvent of the binder. And (3) the method for producing an electrode plate for a battery according to the above (1), wherein the electrode plate is an active material, a binder and a binder. (1) The battery electrode plate and the method for producing the same according to (1), wherein the slurry of the mixture of the solvent of the adhesive is applied to a metal foil current collector, dried, and further roll-pressed. 4) The battery electrode according to the above (1), (2) or (3), wherein the cutting tool is an end mill. The method of manufacturing, (5) the cutting tool is characterized in that it is a wheel grinder (1), there is provided a manufacturing method, the battery electrode plate (2) or (3).

Hereinafter, the present invention will be described in detail. The present invention is to apply an electrode plate composed of an electrode mixture layer containing an active material and a binder as main components and a metal foil current collector to a battery, in order to electrically connect the electrode plate and an external load. In order to prevent the concentration of stress on the bent portion when the lead is attached to the electrode plate and / or when the electrode plate has a bent structure in which mountain folds and valley folds are alternately repeated, the above electrode mixture is used. A rotating cutting tool that can cut not only in the thickness direction of the electrode mixture layer but also in the plane direction of the electrode plate when the metal foil current collector is partially exposed by removing the layer. In particular, an object of the present invention is to provide a method for manufacturing an electrode plate for a battery in which the electrode mixture layer is removed by using an end mill and a grinding wheel with a shaft to partially expose the metal foil current collector.

In the present invention, the electrode mixture layer may be formed by forming a mixture of the electrode active material and the binder, if necessary, by using a conductive filler or a conductive material. A mixture of an electrode active material and a binder is mixed with a conductive filler as necessary, formed by extruding a mixture of molding aids into a sheet and pressing or heat fusing it to a metal current collector. These are formed into a slurry by using a solvent for the binder, applied to a metal foil current collector, and formed by drying and evaporating the solvent.In general, the electrode active material and the binder are used. It is obtained by applying a slurry of a mixture of agents and the like using a solvent for the binder to a metal foil current collector, and drying and evaporating the solvent. In particular, in a lithium ion secondary battery which is expected as a high energy density battery in recent years, this coating method is mainly used. The thickness of the electrode mixture layer is usually about 10 μm to 1 mm, and is appropriately selected from energy density and output characteristics. In the case of a lithium ion secondary battery, the thickness is 50 to 300 μm.

As a specific example, in the case of a lithium ion secondary battery, for example, lithium cobalt oxide, lithium nickel oxide, lithium manganate and the like are used as a positive electrode active material, and coke, In general, graphite, carbon fiber, carbon black, acetylene black and the like are used.
When polyvinylidene fluoride is used as the binder and its solvent, N-methylpyrrolidone shows good solubility. When an ethylene / propylene / diene rubber is used as the binder, toluene and methyl ethyl ketone can be used as the solvent. Further, when a fluorine-based rubber such as vinylidene fluoride, hexafluoropropylene, or tetrafluoroethylene is used as a binder, ethyl acetate or methyl ethyl ketone can be used as a solvent. When using a styrene-butadiene rubber-based binder, a methylcellulose-based binder, or a binder made of polytetrafluoroethylene, water can be used as a solvent.

As the metal foil current collector of the present invention, 5 to 10
Aluminum foil, copper foil, stainless steel foil, nickel foil and the like having a thickness of about 0 μm can be mentioned. Generally, an aluminum foil of 10 to 20 μm for a positive electrode and 10 to 20 μm for a negative electrode
Copper foil is used. The electrode plate is coated or transferred onto a metal foil current collector using a doctor blade, pipe doctor, reverse roll, gravure roll, etc., using a slurry of a mixture of the electrode active material, the binder, and a solvent for the binder. The slurry is extruded from a slit die and coated on a metal foil current collector. The coated slurry and the metal foil current collector are dried using a heating means such as heat transfer, hot air, infrared rays, microwaves, and the like, and the solvent is volatilized. An electrode plate composed of an electrode mixture layer and a metal current collector is firmly integrated via a binder.

The electrode plate of the present invention can be used as it is by applying it to a metal foil current collector as described above and then drying it. Since a battery having a low energy density can be obtained only because of its low density, it is generally preferable to use a roll having a high bulk density by applying pressure between metal rolls. The roll pressure may be such that a desired bulk density can be obtained. For example, the roll pressure is 50 to 5 per cm.
00 kg. The present invention provides, as in the above example, an electrode plate, an electrode active material, a binder, and a mixture slurry of a solvent for the binder applied to a metal foil current collector, dried, and further rolled. It is preferably pressurized.

In the present invention, it is necessary to use a rotating cutting tool capable of cutting not only in the thickness direction but also in the surface direction of the electrode mixture layer, and it is particularly preferable to use an end mill and a grindstone with a shaft. .

[0022]

According to the present invention, a battery electrode plate comprising an electrode mixture layer containing an active material and a binder as main components and a metal foil current collector integrated with the electrode mixture layer is provided. By removing the electrode mixture layer, when using an electrode partially exposed metal foil current collector, without damaging the metal foil current collector, chipping of the electrode mixture layer It does not occur, does not require solvent treatment, and facilitates the treatment of peeled electrode mixture layer scum. Furthermore, since it is not necessary to make an uncoated portion on the metal current collector in advance, the electrode is broken by a roll press or the roll surface is damaged, as in an electrode obtained by intermittent coating. Therefore, it is possible to provide an electrode having a high bulk density in the electrode mixture portion. That is, a high capacity battery electrode can be provided. Further, it is possible to obtain an area in which the metal foil current collector having a width that is difficult by intermittent coating is partially exposed, and to partially expose the metal foil current collector and the area, and the electrode mixture layer. The dimensional accuracy of the remaining area is good, and even if the shape of the area where the metal foil current collector is partially exposed and the area where the electrode mixture layer remains is changed, the program can be performed without changing the equipment jig. It is possible with a change. In addition, it is possible to provide an electrode having an area in which the deformed metal foil current collector is partially exposed by setting a program.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. <Preparation of Electrode Plate>-Electrode plate 1: Lithium cobaltate was used as an electrode active material, an equal weight mixture of graphite fine powder and acetylene black was used as a conductive auxiliary, and polyvinylidene fluoride was used as a binder. The mixture was slurried using N-methylpyrrolidone as a solvent, applied to a 15 μm aluminum foil, and dried with hot air to prepare an electrode plate 1. The thickness of the obtained electrode plate 1 was adjusted through a roll press. The pressed electrode plate 1 had an electrode mixture layer thickness of 85 μm. -Electrode plate 2: using a ternary fluororubber composed of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene instead of polyvinylidene fluoride as a binder,
An electrode plate 2 was prepared in the same manner as the electrode plate 1 except that a mixture of ethyl acetate and ethyl cellosolve was used as a solvent instead of N-methylpyrrolidone. The electrode plate 2 after pressing had an electrode mixture layer thickness of 85 μm. Electrode plate 3: Electrode plate 3 was prepared in the same manner as electrode plate 1 except that lithium manganate was used as the electrode active material. The pressed electrode plate 3 had an electrode mixture layer thickness of 85 μm. -Electrode plate 4: An electrode plate 4 was prepared in the same manner as the electrode plate 1 except that lithium nickelate was used as an electrode active material. The pressed electrode plate 4 had an electrode mixture layer thickness of 85 μm. -Electrode plate 5: An electrode plate 5 was prepared in the same manner as the electrode plate 2 except that lithium nickelate was used as an electrode active material. The electrode plate 5 after pressing had an electrode mixture layer thickness of 85 μm. -Electrode plate 6: using needle coke as an electrode active material, using carboxymethylcellulose and styrene-butadiene latex as a binder, and applying a slurry using water as a slurrying solvent on a 18 µm copper foil,
The electrode plate 6 was prepared by drying with hot air. The thickness of the obtained electrode plate 6 was also adjusted through a roll press. The electrode plate 6 after pressing had an electrode mixture layer thickness of 124 μm. -Electrode plate 7: An electrode plate 7 was prepared in the same manner as the electrode plate 6 except that a finely pulverized carbon fiber was used as the electrode active material and a 12-μm copper foil was used. The electrode plate 7 after pressing had an electrode mixture layer thickness of 85 μm. -Electrode plate 8: An electrode plate 8 was prepared in the same manner as the electrode plate 7, except that graphitized spherical carbon was used as the electrode active material. The pressed electrode plate 8 has a thickness of 85 μm of the electrode mixture layer.
Met. Electrode plate 9: Polyvinylidene fluoride instead of carboxymethyl cellulose and styrene-butadiene latex as a binder, and N instead of water as a slurrying solvent
An electrode plate 9 was prepared in the same manner as the electrode plate 6, except that -methylpyrrolidone was used. The pressed electrode plate 9 had an electrode mixture layer thickness of 125 μm. Electrode plate 10: The same as the electrode plate 7, except that carboxymethylcellulose and styrene-butadiene latex were used as a binder, polyvinylidene fluoride was used as a binder, and N-methylpyrrolidone was used as a slurrying solvent instead of water. It was created. The electrode plate 10 after pressing had an electrode mixture layer thickness of 85 μm. Electrode plate 11: Same as electrode plate 8, except that carboxymethylcellulose and styrene-butadiene latex were used instead of polyvinylidene fluoride as a binder and N-methylpyrrolidone was used as a slurrying solvent instead of water. It was created. The pressed electrode plate 11 had an electrode mixture layer thickness of 85 μm. <Apparatus for installing a rotating cutting tool> An NC vertical milling machine MHNC-25 manufactured by Makino Milling Seiki Co., Ltd. was used. The milling machine has a table movement range of 2
50 mm, vertical 200 mm, axis feed minimum unit 1 μm
However, another milling machine can be appropriately selected according to the size of the sample electrode plate and the dimensional accuracy of the peeled portion. In this embodiment, the batch processing using the single-wafer electrode was performed. However, in the case of production, it is also possible to process a roll-to-roll type continuous electrode by installing an unwinding device and a winding device. It is.

For numerical control, a controller O-MC (hereinafter simply referred to as a controller) manufactured by FANUC CORPORATION was used. This can also be appropriately selected depending on the milling machine or the like to be used. When a very small number of special products are to be prototyped, manual feed can be performed only by the milling machine body without numerical control. Generally, it is preferable to use a programmable control device in terms of reproducibility, convenience, and compatibility with irregular shapes.

The sample electrode plate is installed on a table of an NC vertical milling machine MHNC-25NC manufactured by Makino Milling Seiki Co., Ltd., and a permanent magnetic chuck RMT-10 manufactured by Kanetec Corporation.
18 was fixed with a clamp, and an iron square bar was put on the sample electrode so as to open an area necessary for peeling, and fixed by magnetic force. Also in this case, a partially cut iron plate is used instead of a square bar so that the area required for peeling is open, a vacuum suction table is used, the sample electrode is fixed with a nip roll, If so, it is also possible to fix it on a surface plate with tape or the like. The scum of the peeled coating film was collected by air blow and a dust collector. <Evaluation of peeled portion> After visually confirming the presence or absence of breakage of the current collector metal foil, 10 pieces of the same sample electrode were stacked to form an electrode assembly, and the portion where the metal foil current collector was partially exposed was collectively determined. Judgment was made based on whether ultrasonic welding was possible. As the ultrasonic welding machine, a USW200Z38S type ultrasonic welding machine manufactured by Ultrasonic Industry Co., Ltd. was used. The ultrasonic welding machine has an output of 200 W and a frequency of 38.
kHz.

[0026]

Example 1 An end mill manufactured by Hitachi Tool Co., Ltd. was used as a rotating cutting tool. The end mill is made of material CO
-HSS, two blades with a helix angle of 30 degrees, blade diameter 10
mmφ, blade length 20 mm. The end mill was mounted on a NC vertical milling machine MHNC-25 (hereinafter simply referred to as a milling machine) manufactured by Makino Milling Seiki Co., Ltd. via a collet, the end mill rotation speed was 1500 RPM, and the axial feed during cutting was 400 mm / min. Sample electrode is 125mm
A square electrode 1 of × 125 mm was used. Figure 1
The program was controlled by a controller so that a 90 mm × 14 mm rectangle was formed as the axial feed area at the center of the end mill as shown in FIG.

The obtained electrode mixture layer is partially removed,
The electrode plate 1 in which the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. The required time including the set of samples was 2 minutes per sheet. As illustrated in FIG. 2, the electrode mixture layer portion is 90 mm × 70 mm, and the exposed metal foil portion is 90 m.
10 squares cut into squares of size mx 20 mm
Sheet, and the part where the metal foil current collector is partially exposed
When the sheets were stacked and subjected to ultrasonic welding, the weight was 15 kg,
Welding was possible with a welding time of 0.1 second.

[0028]

Example 2 The same experiment as in Example 1 was performed except that the electrode plate 2 was used as a sample electrode. The obtained electrode plate 2 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. In the same manner as in Example 1, 10 pieces of portions where the metal foil current collectors were partially exposed were overlapped and subjected to ultrasonic weldability evaluation. Under the same conditions as in Example 1, a weight of 15 kg and a welding time of 0.1 were used. Welding was possible in seconds.

[0029]

Example 3 The same experiment as in Example 1 was performed except that the electrode plate 3 was used as a sample electrode. The obtained electrode plate 3 from which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. In the same manner as in Example 1, 10 pieces of portions where the metal foil current collectors were partially exposed were overlapped and subjected to ultrasonic weldability evaluation. Under the same conditions as in Example 1, a weight of 15 kg and a welding time of 0.1 were used. Welding was possible in seconds.

[0030]

Example 4 The same experiment as in Example 1 was performed except that the electrode plate 4 was used as a sample electrode. The obtained electrode plate 4 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. In the same manner as in Example 1, 10 pieces of portions where the metal foil current collectors were partially exposed were overlapped and subjected to ultrasonic weldability evaluation. Under the same conditions as in Example 1, a weight of 15 kg and a welding time of 0.1 were used. Welding was possible in seconds.

[0031]

Example 5 The same experiment as in Example 1 was performed except that an electrode plate 5 was used as a sample electrode. The obtained electrode plate 5 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. In the same manner as in Example 1, 10 pieces of portions where the metal foil current collectors were partially exposed were overlapped and subjected to ultrasonic weldability evaluation. Under the same conditions as in Example 1, a weight of 15 kg and a welding time of 0.1 were used. Welding was possible in seconds.

[0032]

Example 6 Example 1 was repeated except that the electrode plate 6 was used as the sample electrode and the axial feed rate during cutting was 500 mm / min.
The electrode mixture layer was partially removed in accordance with the procedure described above to prepare an electrode plate in which the metal foil current collector was partially exposed. The obtained electrode plate 6 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. The required time including the set of samples was 100 seconds per sheet. Ten pieces were cut out of this into squares such that the electrode mixture layer portion was 90 mm × 70 mm and the exposed metal foil portion was 90 mm × 20 mm, and 10 portions of the metal foil current collector were partially exposed. When ultrasonic welding was performed, the weight was 15
Welding was possible with kg and welding time of 0.4 seconds.

[0033]

Embodiment 7 As a rotating cutting tool, an outer diameter of 10 mmφ
F & S Co., Ltd. G & J cylindrical grinding wheel with shaft was used. The whetstone with a shaft was mounted on a milling machine via a collet, and the rotation speed of the whetstone with a shaft was 1800 RPM, and the speed of shaft feed during cutting was 1000 mm / min. The sample electrode is 125 mm x 1
A 25 mm square electrode plate 6 was used. Among them, as shown in FIG.
The program was controlled by a controller so as to form a rectangle of mm × 14 mm. The obtained electrode plate 6 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. The required time including the set of samples was 74 seconds per sheet. The electrode mixture layer is 90 mm
× 70mm, exposed metal foil part is 90mm × 20mm
Create 10 pieces cut out into squares so that
The metal foil current collector is partially exposed,
When ultrasonic welding was performed, welding was possible under the same conditions as in Example 6 with a load of 15 kg and a welding time of 0.4 seconds.

[0034]

Example 8 An electrode mixture layer was partially removed according to Example 7, except that an electrode plate 7 was used as a sample electrode.
An electrode with a partially exposed metal foil current collector was made. The obtained electrode plate 7 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. As in Example 6, when 10 pieces of the metal foil current collector were partially exposed and the ultrasonic weldability was evaluated, the weight was 15 kg and the welding time was 0.4 under the same conditions as in Example 6. Welding was possible in seconds.

[0035]

Example 9 An electrode mixture layer was partially removed according to Example 6, except that an electrode plate 8 was used as a sample electrode.
An electrode with a partially exposed metal foil current collector was made. The obtained electrode plate 8 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. As in Example 6, when 10 pieces of the metal foil current collector were partially exposed and the ultrasonic weldability was evaluated, the weight was 15 kg and the welding time was 0.4 under the same conditions as in Example 6. Welding was possible in seconds.

[0036]

Example 10 An electrode mixture layer was partially removed according to Example 6, except that an electrode plate 9 was used as a sample electrode.
An electrode with a partially exposed metal foil current collector was made. The obtained electrode plate 9 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. As in Example 6, when 10 pieces of the metal foil current collector were partially exposed and the ultrasonic weldability was evaluated, the weight was 15 kg and the welding time was 0.4 under the same conditions as in Example 6. Welding was possible in seconds.

[0037]

Example 11 An electrode mixture layer was partially removed according to Example 7, except that an electrode plate 9 was used as a sample electrode.
An electrode with a partially exposed metal foil current collector was made. The obtained electrode plate 9 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. As in Example 6, when 10 pieces of the metal foil current collector were partially exposed and the ultrasonic weldability was evaluated, the weight was 15 kg and the welding time was 0.4 under the same conditions as in Example 6. Welding was possible in seconds.

[0038]

Example 12 An electrode in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed was prepared according to Example 7, except that the electrode plate 10 was used as a sample electrode.
The obtained electrode plate 10 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. As in Example 6, when 10 pieces of the metal foil current collector were partially exposed and the ultrasonic weldability was evaluated, the weight was 15 kg and the welding time was 0.4 under the same conditions as in Example 6. Welding was possible in seconds.

[0039]

Example 13 An electrode in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed was prepared according to Example 7, except that the electrode plate 11 was used as the sample electrode.
The obtained electrode plate 11 in which the electrode mixture layer was partially removed and the metal foil current collector was partially exposed had the electrode mixture layer removed without breaking the metal foil current collector. Was. As in Example 6, when 10 pieces of the metal foil current collector were partially exposed and the ultrasonic weldability was evaluated, the weight was 15 kg and the welding time was 0.4 under the same conditions as in Example 6. Welding was possible in seconds.

[0040]

Embodiment 14 An end mill manufactured by Kobe Steel Ltd. was used as a rotating cutting tool. The end mill is made of material C
O-HSS, two blades with a helix angle of 30 degrees, blade diameter 2
mmφ, blade length 5 mm. The end mill is mounted on a milling machine via a collet, and the end mill rotation speed is 1500R.
PM and the axial feed during cutting were at a speed of 400 mm / min. The sample electrode is a square electrode plate 1 of 125 mm × 125 mm.
And the electrode plate 6 was used. Of these, as illustrated in FIG. 3, the center of the end mill is fed 90 mm only in the X direction,
Striped stripped portions were formed at a pitch of 27 mm, and program control was performed with a controller so that three electrode mixture layers having a width of 25 mm and a length of 90 mm were obtained. The electrode plate from which the electrode mixture layer was removed in a stripe shape and the metal foil current collector was exposed in a stripe shape was the electrode plate 1 and the electrode plate 6.
In both cases, the metal foil current collector was not broken and the electrode mixture layer was 2
It was removed in the form of a stripe having a width of mm. This electrode plate was cut into a size of 79 mm × 90 mm as illustrated in FIG. 4 to prepare a unit cell having a bent structure. The outline of the procedure was as follows. First, a gel-like solid electrolyte was prepared as follows. A 100 μm thick gel formed by impregnating a 60 μm thick foam sheet made of vinylidene fluoride and hexafluoropropylene copolymer with an electrolytic solution obtained by dissolving lithium borofluoride in a mixed solvent of propylene carbonate, ethylene carbonate and γ-butyrolactone. A solid electrolyte was obtained. The solid electrolyte is interposed, and the obtained battery electrode 1 and battery electrode 6 are heated at 100 ° C., 1 cm ² using a hot press such that the electrode mixture layer faces the striped stripped portion. Heating and laminating at a pressure of 2 kg per unit, heat bonding the electrode 1, the gel-like solid electrolyte and the electrode 6,
A unit cell was formed. When the cell was alternately subjected to mountain-fold and valley-fold at the stripped stripped portion to form an electrode having a folded structure, the electrode mixture layer portion contained the binder and gel-like solid contained in the mixture layer. The electrolyte is thermally fused, and the stripe portion is free from pressure due to the absence of the binder and the thickness difference of the electrode mixture layer. Not only was it easy to carry out, but a flat unit cell in which the bent portion was not particularly thick could be formed.

[0041]

COMPARATIVE EXAMPLE 1 The electrode 1 was cut into a size of 90 mm × 90 mm, and 90 mm × 70 mm of the electrode 1 was masked with an acrylic plate, and a small amount of N-methylpyrrolidone as a solvent for a binder was added to the exposed 90 mm × 20 mm portion. The electrode mixture layer was dropped and left for about 10 minutes to swell the peeled area. Thereafter, the swollen electrode mixture layer was scraped off with a silicon rubber scraper. With the required time of about 15 minutes, the electrode mixture layer could be peeled off without damaging the metal foil current collector, but the exposed side of the electrode mixture layer on the metal foil current collector side was the solvent. Due to the wraparound, there was no linearity and only a disturbance was obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an axial feed area of a center axis of a cutting tool used in an embodiment.

FIG. 2 is a battery electrode plate obtained in Example 1.

FIG. 3 is an explanatory view showing a process of manufacturing the battery electrode plate obtained in Example 14.

FIG. 4 is a battery electrode plate obtained in Example 14.

Claims (5)

[Claims] 1. An electrode plate composed of an electrode material layer mainly composed of an active material and a binder and a metal foil current collector, and the electrode material layer is removed using a rotating cutting tool. Thereby partially exposing the metal foil current collector, thereby producing a battery electrode plate. 2. The electrode plate according to claim 1, wherein a slurry of a mixture of the active material, the binder and the solvent of the binder is applied to the metal foil current collector and then dried. A method for producing the battery electrode plate according to the above. 3. The electrode plate is characterized in that a slurry of a mixture of an active material, a binder and a solvent of a binder is applied to a metal foil current collector, dried, and further roll-pressed. The method for producing a battery electrode plate according to claim 1. 4. The method for producing an electrode plate for a battery according to claim 1, wherein the cutting tool is an end mill. 5. The method for producing an electrode plate for a battery according to claim 1, wherein the cutting tool is a whetstone with a shaft.