JPH1064525A - Electrode plate for nonaqueous electrolyte secondary battery and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode plate for a nonaqueous electrolyte secondary battery having no adverse effect on battery performance by forming an identification mark with the same material as an active material coating film in the vicinity of a terminal fixing part formed in the active material coating film on a current collector. SOLUTION: An active material coating film comprising an active material and a binder is formed on a current collector except for a terminal fixing part to obtain an electrode plate for a nonaqueous electrolyte secondary battery. An identification mark such as process control mark and bar code is formed with the same material as the active material coating film in the vicinity of the terminal fixing part. The positive active material such as LiCoO2 or a negative active material such as lithium metal and a binder such as thermoplastic resin are mixed with a solvent, and a mixture is applied to the entire surface of a current collector and dried to form the active material coating film. A liquid material is applied to the active material coating film in the specified pattern, solidified, then peeled off together with the coating film. The identification mark together with the terminal fixing part with a predetermined shape is formed in the coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode plate for a non-aqueous electrolyte secondary battery and a method of manufacturing the same. For example, an electrode plate for a non-aqueous electrolyte secondary battery represented by a lithium ion secondary battery and its electrode It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, miniaturization and weight reduction of electronic devices and communication devices have been rapidly progressing, and there is a strong demand for miniaturization and weight reduction of secondary batteries used as power sources for driving these devices. A non-aqueous electrolyte secondary battery represented by a lithium ion secondary battery having a high energy density and a high voltage has been proposed.

As for the electrode plate which greatly affects the performance of the secondary battery, it has been proposed to increase the area of the thin film in order to extend the charge / discharge cycle life and to increase the energy density. I have. For example, JP-A-63-10
As described in JP-A-456-456 and JP-A-3-285262, a conductive agent and a binder are added to a positive electrode active material powder such as a metal oxide, a sulfide, and a halide by an appropriate wetting method. An active material coating solution in the form of a paste is prepared by dispersing and dissolving in an agent (solvent). A current collector made of a metal foil is used as a base, and the coating solution is applied on the base to form a coating film ( A positive electrode plate obtained by forming an active material coating film) is disclosed. At this time, for example, a fluorine-based resin such as polyvinylidene fluoride or a silicone-acrylic copolymer is used as the binder.

In the above-mentioned coated electrode plate,
The binder used in the preparation of the coating solution containing the active material is electrochemically stable with respect to the nonaqueous electrolyte, and does not elute into the electrolyte, and further includes a metal foil. It must be soluble in some solvent so that the coating solution can be applied thinly on the substrate. The active material coating film (coating film) formed by coating and drying is
The coating is required to have flexibility so as not to cause peeling, falling off, cracking, etc. in a battery assembling process, and has excellent adhesion to a current collector made of metal foil. It is required to be a membrane.

[0005]

Here, the electrode plate is usually
It is necessary that a coating film does not exist in a portion where a terminal for extracting a current is attached, or a portion where an electrode plate is bent when a battery is manufactured, and has a non-coated portion. The pattern of the uncoated portion is arbitrarily determined according to the battery design. To create this uncoated part,
At present, the method of directly forming the pattern of the coating part and the non-coating part by mechanical control of the coater head when coating the electrode coating liquid on the current collector, mechanically coating the coating film after drying There is a method of forming an uncoated portion by peeling off by means.

However, in the former method, it is difficult to form a high-speed pattern due to the problem of mechanical accuracy, and the coating film thickness varies. In addition, the latter method has disadvantages such as a long time for stripping, a low patterning accuracy, and powder dropping from an edge of a stripped portion, and at present, almost no industrial implementation is possible. The present inventor has proposed a method for solving the above problem (see Japanese Patent Application No. 8-177507). The present inventor has found that another problem of the prior art can be solved upon making the proposal.

[0007] That is, the above-mentioned electrode plate is produced by coating a wide raw material, then is mass-produced by processes such as pressing, slitting, cutting, and group winding, and is made into a battery through many assembling processes. In order to carry out each process accurately and efficiently, process control marks, cutting marks, and alignment marks are placed on the electrode plate. It is useful to assign an identification symbol of However, when these identification symbols are formed with printing ink or the like, not only does the number of steps for preparing the electrode plate increase, but also the identification symbols formed with printing ink dissolve in the electrolyte solution in the battery after the battery is assembled, and the battery can be used. Due to problems such as adverse effects on performance, it is practically impossible to assign an identification code because it is difficult to select an appropriate printing ink, and the battery manufacturing process management is complicated and inefficient, This has caused defective products and increased manufacturing costs. Therefore, the object of the present invention is
An object of the present invention is to provide a terminal mounting portion and an electrode plate for a non-aqueous electrolyte secondary battery provided with an identification code such as a production lot number that does not adversely affect battery performance.

[0008]

The above object is achieved by the present invention described below. That is, the present invention provides an electrode plate for a non-aqueous electrolyte secondary battery formed by forming an active material coating film composed of an active material and a binder on a current collector except for a terminal attachment portion. An electrode plate for a non-aqueous electrolyte secondary battery, characterized in that an identification symbol made of the same material as the active material coating film is formed in the vicinity of the terminal mounting portion, comprising an active material and a binder. In an electrode plate for a non-aqueous electrolyte secondary battery in which an active material coating film is formed on a current collector except for a terminal attachment portion, an active material coating film near the terminal attachment portion is provided. An electrode plate for a non-aqueous electrolyte secondary battery, wherein an identification symbol obtained by peeling a coating film in a pattern is formed, and a method for producing the same.

According to the present invention, by peeling and removing the active material coating film of the electrode plate in a pattern, the terminal mounting portion and the identification symbol can be simultaneously formed at an arbitrary position on the electrode plate. Since the formed identification symbol is the same as the active material coating film or a cutout shape obtained by removing the film in a pattern, it does not adversely affect the performance of the assembled battery.

[0010]

Next, the present invention will be described in more detail with reference to preferred embodiments. 1 and 2 are diagrams illustrating an electrode plate for a non-aqueous electrolyte secondary battery according to the present invention.
FIG. 1B is a plan view showing a state in which a terminal attachment portion is formed and an identification symbol is formed from an active material coating film formed on the entire surface of the current collector, and FIG. 1B is an enlarged cross-sectional view of a part thereof.
The electrode plate for a non-aqueous electrolyte secondary battery of the present invention may be in the state shown in FIG. 1 or may be cut along the dotted line in FIG. 1a as shown in FIG.

In the electrode plate for a non-aqueous electrolyte secondary battery according to the present invention, a coating liquid comprising an active material and a binder is applied to the entire surface of the current collector and dried to form an active material coated film. Then, the active material coating film of the terminal mounting portion, except for the portion corresponding to the identification symbol, can be obtained by peeling off from the current collector surface, this method is a preferred method in the present invention, the method of the present invention The electrode plate for a non-aqueous electrolyte secondary battery is not limited by the above manufacturing method.

3 and 4 are views for explaining another electrode plate for a non-aqueous electrolyte secondary battery of the present invention. FIG. 3 shows an active material coating film formed on the entire surface of a current collector. FIG. 5 is a plan view showing a state in which a terminal attachment portion is formed, and an active material coating film near the terminal attachment portion is peeled and removed in a pattern to form an identification symbol. The electrode plate for a non-aqueous electrolyte secondary battery of this embodiment may be in the state shown in FIG. 3 or may be cut along the dotted line in FIG. 3 as shown in FIG.

In the electrode plate for a non-aqueous electrolyte secondary battery according to the present invention, a coating liquid comprising an active material and a binder is applied to the entire surface of the current collector and dried to form an active material coated film. Then, the active material coating film of the terminal mounting portion is peeled and removed from the current collector surface, and the active material coating film in the vicinity of the terminal mounting portion is peeled in a pattern to obtain an identification symbol. This method is a preferred method in the present invention, and the electrode plate for a non-aqueous electrolyte secondary battery of the present invention is not limited by the above-described production method.

The present inventor has conducted various studies on a method of forming a terminal mounting portion in a pattern in the manufacture of an electrode plate for a non-aqueous electrolyte secondary battery. As a result of being formed from the material particles and a relatively small amount of the resin binder, the active material coating film is porous, has low adhesion to the current collector, and has a small amount of the resin binder used. We focused on the fact that the cohesive force (strength) in the lateral direction of the active material coating film was low.

That is, since the active material coating film is porous, the liquid easily permeates in the thickness direction of the layer. When the liquid is impregnated into the active material coating film, the liquid is impregnated in an arbitrary pattern, and when the impregnated liquid is solidified, the impregnated portion has a remarkably high physical strength as compared with other non-impregnated portions. However, only the impregnated and solidified portion can be easily separated from the current collector surface, and the current collector surface is exposed in a pattern without leaving any active material coating film on the current collector surface. In the present invention, when the active material coating film is peeled off, the liquid is impregnated in a pattern so that a part of the active material coating film remains in a pattern near the exposed terminal mounting portion. The active material coating film is peeled off, and the remaining patterned active material coating film is used as an identification symbol. It is formed by peeling off.

The above method will be described with reference to the drawings. As shown in FIG. 5, a solidifying agent such as wax is heated and melted and dropped into an active material coating film formed on the current collector surface through an appropriate mask. The dropped wax soaks into the active material coating film and fills the voids of the active material coating film in accordance with the pattern of the mask. At this time, the current collector and / or the active material coated film may be heated in order to prevent the liquid solidifying agent from solidifying before reaching the current collector surface. FIG. 6 shows a state where the solidifying agent has permeated the active material coating film and has been solidified by cooling. In this state, the density of the region impregnated with the solidifying agent is significantly higher than the other regions, and the cohesive force of the region is significantly higher than the other regions.

FIG. 7 shows a state where the solidifying agent-impregnated region has been peeled off. As described above, the solidifying agent-impregnated region has a high density and a high cohesive force due to the filling of the solidifying agent, and the cohesive force of this region is equal to the cohesive force of the adjacent active material coating film not impregnated with the solidifying agent. It is significantly larger in comparison. Therefore, when the solidifying agent-impregnated region is peeled off by an appropriate means, the active material coated film peels sharply in a state of being wrapped in the solidifying agent,
After peeling, the sharp pattern identification symbol and the current collector surface as the terminal attachment portion are exposed. The shape of the pattern of the identification symbol and the terminal attachment portion formed by the present invention is free.

Examples of the solidifying agent used in the present invention include substances which are solid at room temperature and become liquid upon heating, for example, thermoplastic resins, organic or inorganic waxes, or low-melting metals such as lead. For the purpose of the present invention, the solidifying agent has a melting point of 20C to 250C, preferably 60C
About 150 ° C is good. When the melting point is too low, it is soft even at room temperature, so that it is difficult to handle, and the productivity of the electrode plate is inferior. When the melting point is too high, it is uneconomical in energy. The melt viscosity of the solidifying agent is about 10 to 50,000 cP, preferably about 300 to 6000 cP. If the melt viscosity is too high, the solidifying agent does not easily penetrate into the fine voids of the coating film, and the productivity of the electrode plate is inferior.If the melt viscosity of the solidifying agent is too low, the solidifying agent in the molten state is formed by capillary action. It spreads in the lateral direction in the coating film, and it becomes difficult to perform sharp patterning. Further, from the viewpoint of workability at the time of peeling, the adhesion strength between the solidifying agent and the current collector is preferably as small as possible.

Specific examples of the solidifying agent include, for example, polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride resins, polystyrene, polyvinyl acetate, ethylene-vinyl acetate copolymer, and ethylene-vinyl chloride copolymer. Examples include plastic resins, low molecular weight polyethylene, low molecular weight polypropylene, copolymers thereof, synthetic waxes such as microcrystalline wax, oxidized polyethylene wax or mixtures thereof, natural waxes such as carnauba wax, and derivatives or mixtures thereof. .

As the solidifying agent other than the above, there can be used a material which changes from a liquid state to a solid state by a chemical reaction, for example, a polymerizable or crosslinkable liquid substance. For example, various thermosetting materials used in printing inks and paints can be used. Properties, catalyst curability, room temperature curability, electron beam curability, polymerizable or crosslinkable liquid substances such as ultraviolet curability, and the like. Examples of the solidifying method of these solidifying agents include, for example, heat, catalyst, And irradiation of electron beams or ultraviolet rays.

When the solidifying agent is impregnated into the coating film as described above, it is necessary that the solidifying agent reaches the current collector surface through fine voids in the coating film. If the coating is solidified before reaching the temperature, the coating film impregnated with the solidifying agent may be partially removed from the surface of the current collector when the current collector is separated from the coating film. In order to prevent this, the current collector or the coating film or both may be heated to an appropriate temperature to delay the solidification of the solidifying agent, or a solidifying agent having a low melt viscosity may be selected to increase the penetration rate. Alternatively, the temperature of the solidifying agent may be set sufficiently high to delay the time until the liquid solidifying agent solidifies.

When a copper foil is used as the current collector of the negative electrode, the copper foil is oxidized when heated to 140 ° C. or more, and the surface tends to turn red. When the coating film is heated on a hot plate, both surfaces of the copper foil are covered with the coating film, and the heating is performed from the surface on which the solidifying agent is applied.
Even at 40 ° C. or higher, the problem of oxidation of the copper foil does not occur.
Also, when forming a pattern at the same position on both surfaces of the electrode plate, after patterning one surface, when patterning the opposite surface, the copper foil is already patterned and exposed. In order to prevent oxidation of the surface, it is preferable that the coating film is heated by far infrared rays or the like from the surface to be newly patterned so that the exposed surface on the back side is not heated to 140 ° C. or more.

[0023] The method of impregnating the solidifying agent into the coating film in the form of a pattern includes a method of applying the molten solidifying agent in a pattern on the coating film and a method of applying the solidifying agent formed in a pattern to the coating film. A method in which the coating film is heated and the solidifying agent in contact with the coating film is melted by heating the coating film to impregnate the coating film. And a method of applying and impregnating a solidifying agent. When applying the molten solidifying agent, a general application device such as a dispenser, a gravure roll, or a die head can be used. For example, a solidifying agent dropping device as shown in FIG.
The solidifying agent can be dropped in an arbitrary pattern in accordance with the movement of the XY plotter by attaching to a Y plotter type driving device. For example, by operating the XY plotter to draw a character, figure or pattern, it is possible to drop the solidifying agent so as to draw any character, figure or pattern.

The coating film containing the solidified solidifying agent is usually weakly attached to the current collector and can be easily peeled off. At the time of peeling, the current collector may be tensioned to lift off the coating film containing the solidifying agent, and may be peeled off from the current collector, or may be scraped off from the current collector with a spatula-shaped adhesive tape. May be peeled off from the current collector, or may be blown off from the current collector by air. As described above, the impregnation of the solidifying agent into the coating film may be performed on the coating film before pressing as described later or on the coating film after pressing.

Hereinafter, each material constituting the electrode plate when the present invention is used for manufacturing an electrode plate for a non-aqueous electrolyte secondary battery will be described. A non-aqueous electrolyte secondary battery is represented by a lithium-based secondary battery, and is characterized by using a non-aqueous organic solvent for an electrolyte.For example, an electrode active material is formed on a current collector made of a metal foil. An electrode plate is formed with a coating film containing active material (active material coating film), a non-aqueous organic solvent is used as an electrolytic solution, and electron transfer when lithium ions move between the positive electrode and the negative electrode. The exchange enables charging and discharging. The coating film containing the active material constituting the electrode plate for a non-aqueous electrolyte secondary battery of the present invention is formed from an electrode coating solution comprising at least an active material and a binder. As the positive electrode active material used in the present invention, for example, LiCo
Lithium oxides such as O ₂ , LiMn ₂ O ₄ , TiS ₂ , Mn
One of chalcogen compounds such as O ₂ , MoO ₃ and V ₂ O ₅ , or a combination of two or more of these chalcogen compounds is used.

On the other hand, as the negative electrode active material, metal materials such as lithium metal, lithium alloy, and graphite, carbon black, and acetylene black are preferably used. In particular, by using LiCoO ₂ as a positive electrode active material and a carbonaceous material as a negative electrode active material, a lithium secondary battery having a high discharge voltage of about 4 volts can be obtained. It is preferable that these active materials are uniformly dispersed in the formed coating film. For this reason, in the present invention, the average particle size having a particle size in the range of 1 to 100 μm is 10 as an active material.
It is preferable to use a powder of about μm.

Examples of the binder (binder) used in the present invention include thermoplastic resins, that is, polyester resins, polyamide resins, polyacrylate resins, polycarbonate resins, polyurethane resins, cellulose resins, and polyolefin resins. , A polyvinyl resin, a fluorine-based resin, a polyimide resin, or the like. At this time, a compound (acrylate monomer or oligomer) having a reactive functional group introduced therein can be mixed at the same time. In addition, the acrylate oligomer may be used alone, or a mixture of an oligomer and a monomer may be used.

The coating film containing the active material constituting the electrode plate for a non-aqueous electrolyte secondary battery of the present invention is prepared by the following method. First, a coating liquid to be coated on the current collector is prepared using the materials described above. That is, a binder and a powdery active material appropriately selected from the above materials are kneaded or dispersed and dissolved using an appropriate dispersion medium to prepare an electrode coating solution.

Next, using the obtained coating liquid, coating is performed on the current collector. As a coating method, a method such as gravure, gravure reverse, die coating, and slide coating is used. Thereafter, a coating film having a desired film thickness is formed through a drying step of drying the applied coating liquid. As the current collector used for the electrode plate for a non-aqueous electrolyte secondary battery of the present invention, for example, a metal foil such as aluminum or copper is preferably used. The thickness of the metal foil is about 10 to 30 μm.

Hereinafter, a specific method for preparing the electrode coating solution containing the active material used in the present invention will be described. First, a composition in which a binder and a powdery active material appropriately selected from the above-mentioned materials are placed in a dispersion medium composed of an organic solvent such as toluene, and a conductive agent is further mixed as necessary. The product is prepared by mixing and dispersing using a conventionally known disperser such as a homogenizer, a ball mill, a sand mill, and a roll mill.

At this time, the mixing ratio of the binder and the active material may be the same as that conventionally used, for example, it is preferable that the weight ratio of the binder to the active material is about 2: 8 to 1: 9. . In addition, as a conductive agent to be added as necessary,
For example, a carbonaceous material such as graphite, carbon black, and acetylene black is used. The electrode coating solution containing the active material prepared as described above is applied a plurality of times using a gravure coater or gravure reverse, a die coater or the like on a current collector made of a metal foil such as aluminum or copper. Process and drying process, dry film thickness 10 ~ 200
μm, preferably 50 to 170 μm.

Further, in order to further improve the homogeneity of the coating film formed by the coating and drying treatment as described above, a metal roll, a heating roll, a sheet press machine or the like is used for the coating film. It is also preferable that the electrode plate of the present invention is formed by performing a pressing process. The pressing conditions at this time are 50
It is preferably in the range of 0 Kgf / cm ^{2 to} 7,500 Kgf / cm ² , more preferably in the range of 3,000 to 5,000 Kgf / cm ² . If the pressing force is less than 500 kgf / cm ^2, it is difficult to improve the uniformity of the coating film, and if the pressing force is more than 7,500 kgf / cm ^2, the electrode plate including the current collector is not included. It is not preferable because the device itself is damaged.

Further, when a secondary battery is manufactured using the electrode plate of the present invention manufactured as described above, the coating material containing the active material of the electrode plate is required before the process of assembling the battery. In order to remove moisture in the film, it is preferable to further perform a heat treatment, a pressure reduction treatment, or the like. The present invention is to apply the patterning method of the present invention to the electrode plate as described above. Further, using the electrode plate for a non-aqueous electrolyte secondary battery of the positive electrode and the negative electrode of the present invention prepared as described above, for example, when preparing a lithium-based secondary battery, as an electrolyte,
A non-aqueous electrolyte in which a solute lithium salt is dissolved in an organic solvent is used.

The organic solvent used at this time includes cyclic esters, chain esters, cyclic ethers, chain ethers and the like. For example, cyclic esters include propylene carbonate, butylene carbonate, and the like.
γ-butyrolactone, vinylene carbonate, 2methyl-γ-butyrolactone, acetyl-γ-butyrolactone, γ-valerolactone, and the like, and chain esters such as dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate,
Methyl ethyl carbonate, methyl butyl carbonate, methyl propyl carbonate, ethyl butyl carbonate, ethyl propyl carbonate, butyl propyl carbonate, alkyl propionate, dialkyl malonate, alkyl acetate and the like, and the cyclic ethers include tetrahydrofuran , Alkyltetrahydrofuran, dialkylalkyltetrahydrofuran, alkoxytetrahydrofuran,
There are dialkoxytetrahydrofuran, 1,3-dioxolan, alkyl-1,3-dioxolan, 1,4-dioxolan, and the like.
-Dimethoxyethane, 1,2-diethoxyethane, diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, tetraethylene glycol dialkyl ether and the like.

The solute lithium salt which forms a non-aqueous electrolyte with the above organic solvent includes LiClO ₄ , LiB
Inorganic lithium salts such as F ₄ , LiPF ₆ , LiAsF ₆ , LiCl, and LiBr; and LiB (C ₆ H ₅ ) ₄ and LiN
(SO ₂ CF ₃ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiOSO
₂ CF ₃ , LiOSO ₂ C ₂ F ₅ , LiOSO ₂ C ₃ F ₇ , Li
OSO ₂ C ₄ F ₉ , LiOSO ₂ C ₅ F ₁₁ , LiOSO ₂ C ₆
Organic lithium salts such as F ₁₃ and LiOSO ₂ C ₇ F ₁₅ are used.

[0036]

Next, the present invention will be described more specifically with reference to examples and comparative examples. Example 1 First, a positive electrode coating solution containing the positive electrode active material used in this example was prepared by the following method. As a material of the positive electrode coating liquid, L having an average particle size of 10 μm having a particle size of 1 to 100 μm
40 parts by weight of iCoO ₂ powder, 5.0 parts by weight of graphite powder as a conductive material, 4 parts by weight of polyvinylidene fluoride resin (neoflon VDF, VP-850, manufactured by Daikin Industries, Ltd.) as a binder, N-methyl Pyrrolidone 20
It was used in a mixing ratio of parts by weight.

Of these materials, polyvinylidene fluoride is dissolved in N-methylpyrrolidone to prepare a varnish in advance, and other powder materials are added to the obtained varnish. Then, a planetary mixer (Kodaira Co., Ltd.) is used. (Manufactured by Seisakusho Co., Ltd.) for 30 minutes to obtain a positive electrode coating solution containing a positive electrode active material in a slurry state. Using the positive electrode coating liquid obtained above, the first coating of the positive electrode active material coating liquid was performed by a die coater on a current collector made of an aluminum foil having a thickness of 20 μm and a width of 300 mm. Thereafter, a drying treatment was performed at 140 ° C. for 2 minutes to form a coating film containing the positive electrode active material having a dry film thickness of 100 μm on the aluminum foil. Further, the coating film containing the positive electrode active material obtained above was aged in a vacuum oven at 80 ° C. for 48 hours to remove water, thereby producing a positive electrode plate of this example.

Next, a negative electrode coating solution containing the negative electrode active material used in this example was prepared by the following method. As a material for the negative electrode coating liquid, 85 parts by weight of graphite powder, polyvinylidene fluoride resin (neoflon VDF, VP-850)
Using 15 parts by weight of Daikin Industries, Ltd.) and 225 parts by weight of N-methylpyrrolidone as a dispersion medium;
The powder was dispersed using the same dispersing machine and dispersion method as in the case where the positive electrode coating liquid was prepared, to obtain a slurry negative electrode coating liquid. Using the negative electrode coating liquid obtained above, a first coating of the negative electrode coating liquid was performed on a rolled copper foil current collector having a thickness of 15 μm using a die coater. Thereafter, a drying treatment was performed at 140 ° C. for 2 minutes to form a coating film containing a negative electrode active material having a dry film thickness of 100 μm on the copper foil. Further, water was removed in the same manner as in the case of forming the positive electrode plate, thereby producing the negative electrode plate of this example.

The positive electrode plate and the negative electrode plate obtained as described above were placed on a hot plate at 90 ° C. and heated and melted at 250 ° C., and polypropylene (Viscol 550P, Sanyo Chemical Industries, Ltd.) was melted. Width 1 with a dispenser through a metal plate mask corresponding to the negative pattern of the shape shown
After coating in a belt shape of 0 mm and length of 200 mm, the hot plate was removed to solidify the polypropylene. The solidified polypropylene was hard and easily broken, and rose naturally by applying tension to the current collector, and easily separated from the current collector. In addition, the edges of the terminal attachment portion and the pattern of the identification symbol formed in this manner were sharp, and no powder loss of the coating film was observed.

Example 2 An electrode was produced using the same coating liquid and drying conditions as in Example 1. The resulting positive electrode plate and negative electrode plate were placed on a hot plate at 120 ° C. and heated and melted at 250 ° C., and polyethylene (Sunwax 161P, Sanyo Chemical Industries, Ltd.) was used. 10 mm wide and 200 mm long with a dispenser through a metal plate mask
After coating in a strip of mm, the hot plate was removed and the polyethylene was solidified. The solidified polyethylene was tough, and when the end portion was picked up and pulled up, the solidified polyethylene portion was easily peeled off from the current collector while maintaining its shape. In addition, the edges of the terminal attachment portion and the pattern of the identification symbol formed in this manner were sharp, and no powder loss of the coating film was observed.

Example 3 An electrode was produced using the same coating liquid and drying conditions as in Example 1. The obtained positive electrode plate and negative electrode plate were heated to 70 ° C. with an infrared lamp, and heated and melted at 160 ° C. (Mitsubishi Kasei Kogyo Co., Ltd., Diamond Carna 30L), FIG.
10 mm wide and 200 mm long with a dispenser through a metal plate mask corresponding to the negative pattern of the shape shown in a.
After the coating, the infrared lamp was removed and the wax was solidified. The solidified wax was hard and fragile, and the solidified wax part was naturally lifted by applying tension to the current collector and easily peeled off. In addition, the edges of the terminal attachment portion and the pattern of the identification symbol formed in this manner were sharp, and no powder loss of the coating film was observed.

Example 4 An electrode was produced using the same coating liquid and drying conditions as in Example 1. A width of 30 mm and a length of 2 corresponding to the negative pattern having the shape shown in FIG.
Polyethylene melt molded into a ribbon with a thickness of 00 mm and a thickness of 5 mm (Sanwax 161P, Sanyo Chemical Industries, Ltd.)
Was placed, and a hot plate at 250 ° C. was brought into contact with the back of the electrode for about 1 second, and then removed. Polyethylene was solidified while only the surface in contact with the coating film was melted and soaked into the coating film. When the end of the polyethylene ribbon was pinched and pulled up, the polyethylene ribbon was easily peeled off while maintaining its shape. In addition, the edges of the terminal attachment portion and the pattern of the identification symbol formed in this manner were sharp, and no powder loss of the coating film was observed.

Example 5 An electrode was produced using the same coating liquid and drying conditions as in Example 1. The obtained positive electrode plate and negative electrode plate were roll-pressed for 30 minutes.
After pressing at 00 Kgf / cm ² , polypropylene (Sanyo Chemical Industries Co., Ltd. VISCOL 550P) placed on a hot plate at 90 ° C. and melted by heating at 250 ° C.
10 mm wide and 200 mm long with a dispenser through a metal plate mask corresponding to the negative pattern of the shape shown in FIG.
After coating in a strip of mm, the hot plate was removed and the polypropylene was solidified. The solidified polypropylene was hard and easily broken, and rose naturally by applying tension to the current collector, and easily peeled off. In addition, the edges of the terminal attachment portion and the pattern of the identification symbol formed in this manner were sharp, and no powder loss of the coating film was observed.

Comparative Example 1 An electrode was produced under the same coating liquid and drying conditions as in Example 1. An adhesive tape having a width of 10 mm and a length of 200 mm was attached to the obtained positive electrode plate and negative electrode plate, and was peeled off to produce a terminal mounting portion. A large amount of the coating film remained on the peeled surface, and the edge of the pattern thus formed was not sharp, and powder loss of the coating film was observed. or,
Such peeling using an adhesive tape is practically impossible industrially.

Comparative Example 2 An electrode was produced under the same coating liquid and drying conditions as in Example 1. By scraping the coating films of the obtained positive electrode plate and negative electrode plate with a spatula, a terminal mounting portion having a width of 10 mm and a length of 200 mm was produced. A large amount of coating film remains on the release surface,
It was difficult to form a pattern. Also, the current collector was scratched.

Comparative Example 3 An electrode was produced using the same coating liquid and drying conditions as in Example 1. The obtained positive electrode plate and negative electrode plate were kept at room temperature and kept at 250 ° C.
Heat-melted polypropylene (Sanyo Chemical Industry Co., Ltd.)
(Viscol 550P) was applied to a strip having a width of 10 mm and a length of 200 mm using a dispenser, and then completely solidified by air cooling. The coated polypropylene is solidified on the surface of the coating film before permeating into the inside of the coating film, and even if the polypropylene is removed, the coating film adheres to the current collector and remains. Was.

Comparative Example 4 An electrode was produced using the same coating liquid and drying conditions as in Example 1. The obtained positive electrode plate and negative electrode plate were placed on a hot plate at 70 ° C., and a wax (Nippon Seiro Co., Ltd., SP-0145) heated and melted at 160 ° C. was stripped with a dispenser to a width of 10 mm and a length of 200 mm. After coating, the hot plate was removed and the wax was solidified. The melt viscosity of the wax was small, and at the moment of application, the wax spread in the coating film by capillary action, and the edge of the pattern of the terminal attachment portion collapsed.

[0048]

According to the present invention as described above, the active material coating film of the electrode plate is peeled and removed in a pattern form,
The terminal attachment portion and the identification symbol can be simultaneously formed at an arbitrary position on the electrode plate. Since the formed identification symbol is of the same quality as the active material coated film or a cut shape obtained by removing the film in a pattern, the performance of the assembled battery is not adversely affected.

[0049]

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating an electrode plate for a non-aqueous electrolyte secondary battery of the present invention.

FIG. 2 is a diagram schematically illustrating an electrode plate for a non-aqueous electrolyte secondary battery of the present invention.

FIG. 3 is a diagram schematically illustrating an electrode plate for a non-aqueous electrolyte secondary battery of the present invention.

FIG. 4 is a diagram schematically illustrating an electrode plate for a non-aqueous electrolyte secondary battery of the present invention.

FIG. 5 is a diagram schematically illustrating the method of the present invention.

FIG. 6 is a diagram schematically illustrating the method of the present invention.

FIG. 7 is a diagram schematically illustrating the method of the present invention.

Claims (11)

[Claims] 1. An electrode plate for a non-aqueous electrolyte secondary battery, wherein an active material coating film comprising an active material and a binder is formed on a current collector except for a terminal mounting portion. An electrode plate for a non-aqueous electrolyte secondary battery, wherein an identification symbol made of a material of the same quality as the active material coating film is formed near an attachment portion. 2. An electrode plate for a non-aqueous electrolyte secondary battery in which an active material coating film comprising an active material and a binder is formed on a current collector except for a terminal mounting portion, An electrode plate for a non-aqueous electrolyte secondary battery, wherein an identification symbol obtained by peeling the active material coating film in a pattern is formed on the active material coating film near the attachment portion. 3. The electrode plate for a non-aqueous electrolyte secondary battery according to claim 1, wherein the identification symbols are a process control mark, a production lot number, a bar code, a cutting mark, and a positioning mark. 4. An active material coating film is formed by applying and drying a coating solution comprising an active material and a binder on the entire surface of the current collector, and identifying the active material coating film at the terminal mounting portion. A method for producing an electrode plate for a non-aqueous electrolyte secondary battery, wherein the electrode plate is separated and removed from a surface of a current collector except for portions corresponding to symbols. 5. A coating solution comprising an active material and a binder is applied to the entire surface of the current collector and dried to form an active material coating film, and the active material coating film at the terminal mounting portion is collected. A method for manufacturing an electrode plate for a non-aqueous electrolyte secondary battery, wherein the electrode plate is peeled off from the body surface and the active material coating film near the terminal attachment portion is peeled off in a pattern to form an identification symbol. 6. The active material coating film is peeled and removed by solidifying the active material coating film in a desired pattern into a liquid material having a larger cohesive force than the active material coating film after solidification. The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to claim 4, wherein after solidification, the active material coated film impregnated with the solidified material is peeled off. 7. The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to claim 4, wherein the liquid substance is a substance which is solid at room temperature and becomes liquid when heated. 8. The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to claim 4, wherein the substance which becomes liquid by heating is a thermoplastic resin, an organic or inorganic wax, or a low melting point metal. . 9. The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to claim 4, wherein a viscosity of the substance which becomes liquid by heating is in a range of 10 to 50,000 cP. 10. The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to claim 4, wherein the melting point of the substance which becomes liquid by heating is in the range of 20 ° C. to 250 ° C. 11. The non-aqueous electrolyte solution according to claim 4, wherein the substance which becomes liquid by heating is polyethylene, polypropylene, low molecular weight polyethylene, low molecular weight polypropylene, wax, a derivative thereof, or a mixture thereof. Method for manufacturing electrode plate for secondary battery.