JPH11354103A - Electrode plate for nonaqueous electrolyte secondary battery, its manufacture, and its intermediate product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently provide an electrode plate smaller in deformation, by providing an active material layer on a collector, forming a non-coated part where one side edge of the collector is exposed in a band-like manner, and providing a pressed intermediate product having a plurality of side-by-side arranged cut lines crossing the flow direction. SOLUTION: An electrode plate 1A is equipped with a collector 2, an active material layer 3 formed on one side thereof by a coating method, and a relatively wide non-coated part 4 having a specific function as well as a relatively narrow unneeded non-coated part 5, formed by exposing, in a band-like manner, both ends and one side edge of the collector 2. A plurality of cut lines 6a, 6b, 6c,... crossing the flow direction d of the unneeded non-coated part 5 are made side by side in the unneeded non-coated part 5 existing on the one side edge of the electrode plate 1A. To obtain an intermediate product of the electrode plate 1A, with the unneeded non-coated part 5 left as it is, the active material layer 3 is compacted by pressing only a portion where the active material layer 3 is formed, as a result, only the pressed portion is extended, and therefore deformation of the electrode plate 1A is very small.

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 represented by a lithium ion secondary battery (hereinafter sometimes referred to as an "electrode plate"), an intermediate product thereof, and a method for producing the same. . More specifically, the present invention relates to an intermediate product of an electrode plate that is not easily deformed even by press working, and an electrode plate that is made from the intermediate product and has little deformation. The present invention also relates to a method for efficiently manufacturing an electrode plate having an uncoated portion where a current collector is exposed.

[0002]

2. Description of the Related Art In recent years, the size and weight of electronic devices and communication devices have been rapidly reduced, and the size and weight of secondary batteries used as power sources for driving these devices have been demanded. . For this reason, 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 instead of a conventional alkaline storage battery.

The positive and negative electrode plates, which greatly affect the performance of the secondary battery, are manufactured by reducing the thickness of the electrode plates in the battery in order to extend the charge / discharge cycle life and increase the energy density. It has been proposed to increase the area of the electrode plate to be wound.

For example, JP-A-63-10456 and JP-A-3-285262 disclose a powder of a positive electrode active material such as a metal oxide, a sulfide or a halide, a conductive material and a binder. Dispersing or dissolving in a suitable wetting agent (hereinafter referred to as a solvent) to prepare a paste-like active material coating solution, using a current collector made of metal foil as a base, and applying the coating liquid on the base Then, a positive electrode active material layer (the one obtained by applying a coating liquid for a negative electrode on a substrate is referred to as a negative electrode active material layer, and when no distinction is made between the positive electrode and the negative electrode, simply referred to as an active material layer) The resulting positive electrode plate is disclosed. In this positive electrode plate, for example, a fluorine-based resin such as polyvinylidene fluoride, a silicone-acryl copolymer, a styrene-butadiene copolymer, or the like is used as a binder.

On the other hand, a negative electrode plate is prepared by dissolving a binder in an appropriate wetting agent (solvent) and adding it to a negative electrode active material such as carbon to prepare a paste-like active material coating solution. It is obtained by coating a foil current collector. Further, in order to increase the density of the coating film on the current collector or to improve the adhesion of the coating film, a press treatment is usually performed.

A binder for preparing an active material coating liquid in the above-mentioned coating type electrode plate is chemically stable with respect to a non-aqueous electrolyte, does not elute into the electrolyte,
It is necessary to be able to dissolve in some solvent and apply thinly on the substrate.

Further, the applied and dried active material layer has flexibility so as not to cause peeling, falling off, cracking, etc. in the battery assembling process, and has good adhesion to the current collector. It is required to be excellent.

[0008] Here, the electrode plate usually has a portion to which a terminal for taking out a current or a portion where the active material layer is not preferable in battery design has a not-yet-uncoated portion. The pattern of the uncoated portion is arbitrarily determined according to the battery design. At present, the method of producing the non-coated portion directly forms the pattern of the coated portion and the non-coated portion by mechanical control of a coater head when the electrode coating liquid is coated on the current collector. And a method of forming a non-coated portion by peeling the coated film after drying by a mechanical means such as a spatula.

In the former method, an active material coating solution is applied in a pattern on the surface of a current collector while mechanically controlling a coater head, and dried to form an electrode plate having an active material layer. After preparing the raw material, the raw material of the electrode plate is cut in a predetermined direction to cut out a product of the electrode plate.

For example, as shown in FIG. 12, a long metal foil fed from a roll stock and having a length of 300 to 6 mm is used.
A current collector having a width of about 00 mm is used as the current collector 102, and rectangular active material layers 103 are formed in a line along the longitudinal direction of the current collector. Each active material layer has a size in which some uncoated portions 108a remain on both side edges of the current collector in the width direction of the current collector, and about 300 to 600 mm in the longitudinal direction of the current collector. Having the following dimensions. The uncoated portion 108b between the adjacent active material layers has a length of 15 to 6 in the longitudinal direction of the current collector.
It may have a dimension of about 0 mm. As shown in FIG. 13, after the strip-shaped uncoated portions left on both sides of the raw sheet are cut off in a process called trimming, as shown in FIG. Several slits are made along the longitudinal direction of the raw material so as to have a width of about 30 to 50 mm, and an elongated tape-shaped electrode plate having an uncoated portion 108b is cut out.

In the latter method, an active material coating solution is applied to the surface of the current collector and dried to produce a raw material of an electrode plate having the active material layer. The uncoated portion is formed by using the mechanical means described above, and then the raw material of the electrode plate is cut in a predetermined direction to cut out a product of the electrode plate.

For example, as shown in FIG. 15, a long metal foil fed from a roll stock and having a length of 300 to 6 mm is used.
A current collector having a width of about 00 mm is used as the current collector 102, and a continuous unbroken active material layer 103 is formed on the surface of the current collector on both side edges of the current collector with a slight uncoated portion 108 a. After being formed so as to remain, as shown in FIG. 16, the uncoated portion 10 of about 15 to 60 mm is provided at predetermined intervals of about 300 to 600 mm in the longitudinal direction of the current collector.
The active material layer is scraped off using a spatula or the like so that 8b is formed. After that, as in the former method,
In a process called trimming, strip-shaped uncoated portions left on both sides of the raw material of the electrode plate are cut off.
Several slits are made along the longitudinal direction of the raw material so as to have a width of about 50 mm, and an elongated tape-shaped electrode plate having an uncoated portion is cut out (FIG. 13, FIG.
(FIG. 14).

[0013]

The conventional method has the following problems.

(1) When the active material coating liquid is applied to one entire surface of the electrode plate, the coating liquid protrudes from the edge and goes around to the rear surface, so that a small margin remains on the peripheral edge of the current collector. Thus, the active material layer is formed. Therefore, a strip-shaped uncoated portion inevitably remains on the peripheral portion of the raw material of the electrode plate (for example, both side portions of the long raw material), and the uncoated portion of the peripheral portion is removed in the trimming process. Had to be resected. The problem is that the active material layer is formed by applying the active material coating solution, whether it is applied in a pattern or after application using a spatula etc. It is.

(2) A method of directly forming a pattern of a coated part and a non-coated part by mechanical control of a coater head is not sufficient in mechanical precision. Therefore, when high-speed coating is performed, a desired pattern can be accurately formed. It is difficult to form, and the thickness of the coating film tends to vary. Further, when the pattern of the coated part and the uncoated part is directly formed, the coated part and the uncoated part are complicated at the time of pressing, so that it is difficult to perform a uniform and high-speed pressing process. Furthermore, there is a problem that it is difficult to apply a pattern in which the uncoated portions on the front and back sides do not match.

(3) In the method in which a predetermined area of the active material layer on the current collector is peeled off by a mechanical means to form an uncoated portion, it takes a long time to peel off, and the patterning accuracy is not high. There are problems such as powder falling off from the edge of the peeled portion, and there is almost no practicality at present.

Therefore, the present inventors applied a coating solution containing an active material on the current collector so that the peripheral portion of the current collector was left exposed in a band shape, and reduced the raw material of the electrode plate. The electrode plate was prepared by preparing and then cutting out the uncoated portion left in a band shape on the periphery of the raw material to a predetermined size without cutting off. In the electrode plate thus prepared, the exposed portion of the current collector, which is inevitably left at the periphery of the raw material, is used as it is as an uncoated portion having a unique function such as a terminal mounting portion. ing. Therefore, it is not necessary to remove the peripheral portion of the raw material by trimming. Further, there is no need to apply a coating liquid in a pattern or to form an uncoated portion by peeling the active material layer in a pattern.

However, if pressing is performed with the exposed portion of the current collector remaining at the peripheral edge of the raw material, only the portion where the active material layer is provided is pressed, and only the pressed portion extends in the flow direction. . As a result of such non-uniform elongation, the electrode plate is deformed as shown in FIG. If a soft material is used as a coating material for the active material layer, such deformation of the electrode plate can be reduced, but the type of material is limited. In particular, an industrial medium-sized or large-sized electrode plate is greatly deformed by press working, so that it is difficult to increase the density of the active material layer.

The present invention has been accomplished to solve these problems. That is, an object of the present invention is to provide a method for manufacturing an electrode plate which is less deformed when an electrode plate having an uncoated portion is pressed. A second object of the present invention is to provide a high-quality electrode plate manufactured by a manufacturing method capable of achieving the first object, and an intermediate product therefor.

[0020]

According to the present invention, there is provided an active material layer comprising at least a current collector, an active material and a binder, provided on the current collector. And at least one uncoated portion formed by exposing at least one end or one side edge of the current collector in a strip shape, and a plurality of cuts intersecting the flow direction of the uncoated portion and being arranged side by side with each other. The present invention provides an electrode plate for a non-aqueous electrolyte secondary battery produced by press working an intermediate product containing.

As a preferable method for manufacturing the above-mentioned electrode plate, an active material coating liquid containing at least an active material and a binder is coated on at least one of the peripheral portions of the current collector. The intermediate product of the electrode plate is prepared by applying so that the portion remains exposed in a band shape, and the uncoated portion left in a band shape on at least a part of the peripheral portion of the intermediate product intersects the flow direction thereof. And making a plurality of cuts side by side with each other, and then press working the intermediate product,
Provided is a method for manufacturing an electrode plate for a non-aqueous electrolyte secondary battery.

When the active material coating liquid is applied to the surface of the current collector, a margin is made around the current collector so that the coating liquid does not flow to the back side. A strip-shaped uncoated portion inevitably remains on the periphery of the raw material. Conventionally, the strip-shaped uncoated portion was cut off as an unnecessary portion. On the other hand, according to the present invention, the band-shaped uncoated portion inevitably left on the peripheral edge of the raw material of the electrode plate is replaced with an uncoated portion having a specific function required for the electrode plate (for example, It can also be used effectively as a terminal mounting part).

Further, according to the present invention, since the coating liquid for the active material layer is not applied in a pattern, there is no need to move the coater head in a complicated manner, and a coating film having uniform thickness is formed at a high speed. can do. Furthermore, according to the present invention, since a part of the coating film is not scraped off from the current collector with a spatula or the like, powder is hardly dropped from the edge of the coating film.

Further, according to the present invention, since a notch is formed in a strip-shaped uncoated portion on the peripheral portion of the electrode plate or an intermediate product thereof, and then press processing is performed, the active material layer of the electrode plate is formed by pressing pressure. Even if only the portion extends in the flow direction, uneven stress is hardly applied to the electrode plate, and the electrode plate is hardly deformed.

[0025]

Next, the present invention will be described in more detail with reference to preferred embodiments.

The electrode plate of the present invention has an uncoated portion in which at least one end or one side edge of the current collector is exposed in a strip shape, and the uncoated portion intersects the flow direction and is mutually separated. There are multiple cuts side by side. Specifically, those having shapes as shown in FIGS. 1, 3 and 5 can be exemplified.

The electrode plate 1A shown in FIG. 1 is formed by forming a current collector 2, an active material layer 3 formed on one side of the current collector by a coating method, and exposing both ends and one side edge of the current collector in a band shape. Uncoated portions 4 and 5 are provided. FIG. 2 is a sectional view taken along the line AA in FIG.
Shown in The relatively wide uncoated portions 4 at both ends of the electrode plate 1A are originally formed when the active material layer is coated, but are used as terminal mounting portions. On the other hand, the narrow uncoated portion 5 on one side edge of the electrode plate 1A is also inevitably formed when the active material layer is coated, but is different from the uncoated portions 4 at both ends. This is an unnecessary part for the electrode plate 1A. In the electrode plate of the present invention, at least one portion of the uncoated portion remaining on the peripheral portion of the current collector when the active material layer is coated is replaced with an uncoated portion having a unique function such as a terminal mounting portion. Use as a part.

A plurality of cuts 6 (6a, 6b, 6c...) Intersecting the flow direction d of the uncoated portion 5 are formed side by side in the uncoated portion 5 on one side edge of the electrode plate 1A. ing. In the electrode plate 1A, a cut 6 perpendicular to the flow direction d of the uncoated portion 5 is formed. This cut 6 is made of the electrode plate 1
In the stage before press working the intermediate product of A, the uncoated part 5
It was put in.

The electrode plate 1A is pressed to compact the active material layer 3. Electrode plate or its intermediate product,
When pressing is performed while leaving an uncoated portion in a strip shape on the peripheral portion, only the portion where the active material layer is formed is pressed, and only the electrode plate in that portion extends in the flow direction. As a result, the non-uniform elongation of the electrode plate occurs between the portion where the active material layer is formed and the uncoated portion at the peripheral portion, and the electrode plate is deformed. On the other hand, since the electrode plate 1A is press-processed after making a cut 6 in the uncoated portion of the side edge in advance, uneven stress generated by stretching only the pressed portion is released. And very little deformation.

There are no cuts in the uncoated portions 4 at both ends of the electrode plate 1A. Since the uncoated portions 4 at both ends are short in length, even if pressing is performed without making a cut, no significant deformation is caused. Thus, in the present invention,
The cuts in the uncoated portion may be partially omitted in consideration of the time and effort for processing the cuts.

The electrode plate 1B shown in FIG. 3 is a long electrode plate, and is formed on both surfaces of the current collector 2 by exposing an active material layer 3 formed by a coating method, and exposing one side edge in a strip shape. The uncoated part 4 is provided. FIG. 4 shows a BB cross section of FIG. The uncoated part 4 is used as a terminal attachment part. The plurality of cuts 6 (6 a, 6 b, 6 b, 6 b, 6 b) that intersect with the flow direction of the uncoated
6c ...) are placed side by side.

The electrode plate 1C shown in FIG. 5 is also a long electrode plate, and a strip-shaped uncoated portion 4 which can be used as a terminal attaching portion is provided on both side edges thereof. Cuts 6 (6a, 6b, 6c...) Are formed side by side in the cut portion. In the case of the electrode plate 1C shown in FIG. 5, only the uncoated portion on one side actually attaches the terminal, but providing the uncoated portion on both side edges prevents the active material layer from falling off from the side edge portion. Can be prevented.

As an example of manufacturing the electrode plate 1A shown in FIG. 1, first, as shown in FIG. 6, a sheet-like current collector 2 having a rectangular shape is prepared, and an active material coating solution is applied to the upper surface thereof.・
The active material layer 3 is formed by drying, and a raw material (an intermediate product before cutting out) 7 of the electrode plate is manufactured. In the present invention, an active material layer may be formed on both surfaces of the current collector.

The method for applying the active material coating liquid is not particularly limited, but for example, it can be applied by a screen printing method. Examples of the screen include a screen manufactured by Takagi Sculpture Co., Ltd. having a thickness of 120 μm, 60 lines, and an aperture ratio of 34%. The screen mesh needs to be adjusted according to the amount and viscosity of the ink to be applied. The size of the screen is adjusted to the area where the active material coating liquid is applied.

When an active material coating liquid is applied to the surface of the current collector to produce a raw material for an electrode plate, a margin is provided on the periphery of the current collector so that the coating liquid does not flow to the back side. Therefore, strip-shaped uncoated portions 8a and 8b necessarily remain at the peripheral edge of the raw material of the obtained electrode plate. Of these uncoated portions, the uncoated portions 8a at both ends of the web are portions that will eventually become terminal mounting portions, and therefore have a width necessary to exhibit the function as a terminal mounting portion. There must be. On the other hand, the uncoated portions 8b on both side edges of the raw material are unnecessary portions for the electrode plate. Therefore, it is preferable that the width be as narrow as possible as long as the coating liquid does not flow to the back side of the current collector. Therefore, if necessary,
The coating area may be adjusted so that the width of the uncoated portion 8a at both ends of the raw sheet is just the width suitable for the terminal mounting portion.

That is, in the manufacturing method of the present invention, even if the coating is performed so that the strip-shaped uncoated portion inevitably formed in the peripheral portion of the raw material of the electrode plate has a uniform width over the entire peripheral portion. Also, the width of the band-shaped uncoated portion inevitably formed in the peripheral portion of the raw material of the electrode plate is adjusted so that the uncoated portion can finally exhibit the function required for the electrode plate. Coating may be performed by adjusting the width so as to have an appropriate predetermined width according to the location of the uncoated portion.

Through the above-mentioned coating process, a raw material of the electrode plate 1A having an uncoated portion having a predetermined width at the peripheral portion is manufactured. Next, as shown in FIG. 7 (1) and FIG. 7 (2), the raw material is cut along the longitudinal direction and is divided into two equal parts. In this cutting step, it is not necessary to cut off the uncoated portions 8a and 8b. A plurality of cuts 6 (6a, 6) intersecting the flow direction of the uncoated portion 8b are formed in the uncoated portion 8b on one side edge of the halved material.
b, 6c) are placed side by side to obtain an intermediate product of the electrode plate. This intermediate product has the same appearance as the finished electrode plate 1A (see FIG. 1). In the uncoated portion, cuts perpendicular to the flow direction of the uncoated portion are formed at regular intervals. The distance between the cuts is appropriately adjusted according to the size of the electrode plate to be produced, but if the electrode plate is of a general size, the distance between the cuts is 10 to 60.
mm is preferable. If the deformation of the electrode plate due to press working can be sufficiently prevented without making a cut in the entire area of the uncoated part, the cut in the uncoated part may be partially omitted.

After the cuts are formed, the intermediate product of the electrode plate is pressed to compact the active material layer to increase its density and homogeneity, thereby completing the electrode plate 1A. The press working is performed using, for example, a metal roll, an elastic roll, a heating roll, a sheet press, or the like. The pressing pressure is usually 500 to 7500 kgf / cm ² , preferably 300
It is 0 to 5000 kgf / cm ² . 500kgf / c
If the pressing pressure is lower than m ^2, it is difficult to obtain uniformity of the active material layer, and if the pressing pressure is higher than 7,500 kgf / cm ^2, the electrode plate itself including the current collector may be damaged. The active material layer may have a predetermined thickness by one press, or may be pressed several times in order to improve homogeneity.

When the pressure of the roll press is controlled by the linear pressure, the pressure is adjusted according to the diameter of the pressure roll, but usually the linear pressure is 0.5 kgf / cm to 1 tf / cm. Pressing may be performed several times in consideration of the thickness of the electrode plate after pressing.

The production method of the present invention can be applied to continuous mass production of electrode plates using a long current collector. The above-mentioned electrode plates 1B and 1C can be efficiently manufactured from a long current collector.

As an example of manufacturing the electrode plate 1B shown in FIG. 3, first, as shown in FIG. 8, the active material is coated on both sides of a current collector 2 having a width of about 300 to 600 mm supplied from a roll stock or the like. After the working liquid is applied in a strip shape along the longitudinal direction, the coating film is dried to form the active material layer 3, and a raw material of an electrode plate having strip-shaped uncoated portions 8c on both side edges is produced. . When applying the active material coating liquid to the long current collector, a margin for coating is provided on both side edges of the current collector so that the coating liquid does not flow to the back side. Therefore, in the produced raw material, a band-shaped uncoated portion 8c is inevitably left on both side edges, and a band-shaped uncoated portion 8d is left at one end. The uncoated portions 8c on both side edges are portions that will eventually become terminal mounting portions.
A width of about 60 mm is required. Therefore, when applying the active material coating liquid, the uncoated portion 8c may be adjusted so as to have an appropriate predetermined width so as to function as a terminal attachment portion.

Next, from the raw material of the obtained electrode plate, FIG.
As shown in (1), the uncoated portion 8d at one end of the web is cut off, and then the uncoated portion 8c at the side edge of the web is left uncut and the end of the web is left. When the edge is cut in the longitudinal direction from the center point 9a, the raw material is divided into two as shown in FIG. 9 (2). Then, a cut is made in each uncoated portion 8c of each of the two halved raw materials, and pressing is performed to obtain the electrode plate 1B. The electrode plate 1B has a strip-shaped uncoated portion 4 that can be used as a terminal mounting portion on one side edge thereof, and since it is long, it is usually rolled and shipped. .

As an example of manufacturing the electrode plate 1C shown in FIG. 5, first, as shown in FIG. 10, a current collector 2 having a width of about 300 to 600 mm supplied from a roll stock or the like is used.
, Two active material layers 3 extending in the longitudinal direction of the current collector
To form At this time, strip-shaped uncoated portions 8e and 8f extending in the longitudinal direction of the current collector are formed in stripes on both sides of each active material layer, and these uncoated portions are finally formed on the electrode plate. Used as a terminal mounting part. Therefore, when applying the active material coating liquid, the uncoated portions 8e and 8f may be adjusted to have a predetermined width suitable for functioning as a terminal mounting portion. For example, when a current collector having a width of about 600 mm is used, the width of each of the two active material layers is 24
Uncoated portion 8e on both sides of the current collector
Is about 30 mm, and the width of the uncoated portion 8f between the two active material layers is about 60 mm, which is twice as large.

Next, from the raw material of the obtained electrode plate, FIG.
As shown in (1), the uncoated portion 8g at the end of the web is cut off, and then the uncoated portions 8e at both side edges of the web are left without being cut off, and the uncoated portion 8g is cut off. When the material is cut in the longitudinal direction from the center point 9b of the edge portion, the material is bisected as shown in FIG. 11 (2). Then, when a cut is made in the uncoated portions 8e and 8f on both side edges of each of the two halves of the raw material to be pressed, an electrode plate 1C is obtained. The obtained electrode plate 1C is a long electrode plate having a width of about 300 mm, and has an active material layer 3 having a width of about 240 mm.
It has a strip-shaped uncoated portion 4 of mm and is usually wound in a roll and shipped.

Next, each material constituting the electrode plate for a non-aqueous electrolyte secondary battery of the present invention will be described.

As the current collector 2 serving as a base, a metal foil is usually used, an aluminum foil is preferably used as a positive electrode plate, and a copper foil is preferably used as a negative electrode plate. The thickness of these metal foils is usually about 10 to 20 μm. In the present invention, even if the thickness of the current collector is in the range of 10 to 50 μm, deformation of the electrode due to press working can be prevented.

An active material coating solution containing at least an active material and a binder is applied to one side or both sides of the current collector, and the coated film is dried to form an active material layer. In order to improve the adhesion between the current collector and the active material layer, a coupling agent layer may be formed on the surface of the current collector. As the coupling agent, for example, silane-based, titanate-based,
A coupling agent such as an aluminum-based coupling agent can be used, and among these, those having excellent adhesion between the metal foil current collector and the active material layer are selected and used.

The active material includes a positive electrode active material and a negative electrode active material. Examples of the positive electrode active material include LiCoO ₂ , LiN
Examples thereof include lithium oxide such as iO ₂ or LiMn ₂ O ₄ , or chalcogen compounds such as TiS ₂ , MnO ₂ , MoO ₃ or V ₂ O ₅ . These positive electrode active materials may be used alone or in combination of two or more. As the negative electrode active material, for example, a lithium-containing metal such as lithium metal or a lithium alloy, or a carbonaceous material such as graphite, carbon black or acetylene black is preferably used. In particular, Li
Using CoO ₂ or LiMn ₂ O ₄ as a positive electrode active material,
By using a carbonaceous material as the negative electrode active material, a lithium secondary battery having a high discharge voltage of about 4 volts can be obtained. The positive electrode active material and the negative electrode active material are 1 to 100 μm in order to uniformly disperse these active materials in the active material layer.
And a powder having an average particle diameter of 5 to 40 μm.

The binder is electrochemically stable with respect to the non-aqueous electrolyte, does not elute in the electrolyte, and can be applied thinly on the current collector made of metal foil. Need to be soluble in some solvent. As the binder, for example, thermoplastic resin, more specifically polyester resin, polyamide resin, polyacrylate resin, polycarbonate resin, polyurethane resin, cellulose resin, polyolefin resin, polyvinyl resin, fluorine resin or polyimide resin Etc. can be used. At this time, an acrylate monomer or oligomer having a reactive functional group introduced therein can be mixed into the binder. In addition, it is also possible to use a rubber-based resin, a thermosetting resin such as an acrylic resin or a urethane resin, an ionizing radiation-curable resin composed of an acrylate monomer, an acrylate oligomer or a mixture thereof, and a mixture of the above various resins. it can.

The coating liquid is prepared by adding an appropriately selected active material and a binder to a dispersion medium or a solvent comprising an organic solvent such as N-methyl-2-pyrrolidone, toluene, methyl ethyl ketone or a mixture thereof. Further, if necessary, a conductive material may be mixed and mixed and dispersed by a dispersing machine such as a homogenizer, a ball mill, a sand mill, a roll mill, or a planetary mixer. When the total amount of the coating liquid is 100 parts by weight, the total amount of the active material and the binder therein is preferably about 40 to 80 parts by weight. Also,
The compounding ratio of the active material and the binder may be the same as the conventional one. For example, in the case of the positive electrode active material, the binder: active material = 5: 5 to 1:
It is preferably about 9 (weight ratio), and in the case of the negative electrode active material, it is preferable that the binder: active material = about 2: 8 to 1: 9 (weight ratio). As the conductive material, a carbonaceous material such as graphite, carbon black, or acetylene black is used as necessary.

The adjusted coating liquid is prepared by gravure coat, gravure reverse coat, roll coat, Meyer bar coat, blade coat, knife coat, air knife coat, slot die coat, slide die coat, dip coat, die coat, comma roll coat, The active material layer is formed by applying a method such as a converse reverse coating on a current collector as a substrate and drying the applied material.

The active material layer may be formed by repeating coating and drying a plurality of times. As a heat source in the drying step, for example, hot air, infrared light, microwave, high frequency, or a combination thereof is used. In the drying step, a metal roller, a metal sheet, or the like supporting the current collector may be heated, and the coating film may be dried using the heat released. After drying, the active material layer can be obtained by irradiating an electron beam or radiation to cause a crosslinking reaction of the binder. Thus, the thickness of the active material layer is usually set to 1
The range is from 0 to 200 μm, preferably from 50 to 170 μm. Further, it is preferable that the obtained active material layer is aged in a vacuum oven or the like to remove moisture in the active material layer.

When a secondary battery is manufactured using the electrode plate manufactured through each of the above-described steps, a heat treatment or the like is performed to remove water in the active material layer before moving to a battery assembling step. It is preferable to perform a reduced pressure treatment or the like in advance.

Using this electrode plate, for example,
When manufacturing a secondary battery, a lithium salt
A non-aqueous electrolyte dissolved in an organic solvent is used. Lithium salt
As, for example, LiClO_Four, LiBF_Four, LiPF
₆, LiAsF₆Lithium, such as LiCl, LiBr
Salt or LiB (C₆H_Five)_Four, LiN (SO_TwoC
F _Three)_Two, LiC (SO_TwoCF_Three)_Three, LiOSO_TwoCF_Three,
LiOSO_TwoC_TwoF_Five, LiOSO_TwoC_ThreeF₇, LiOSO_Two
C_FourF₉, LiOSO_TwoC_FiveF₁₁, LiOSO_TwoC₆F₁₃, L
iOSO_TwoC₇F_FifteenAnd the like are used.

Examples of the organic solvent for dissolving the lithium salt include cyclic esters, chain esters, cyclic ethers, and chain ethers. More specifically,
Examples of the cyclic esters include propylene carbonate, butylene carbonate, γ-butyrolactone, vinylene carbonate, 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, and γ-valerolactone.

Examples of the chain esters include 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, and alkyl propionate. Examples thereof include esters, dialkyl malonates, and alkyl acetates.

Examples of the cyclic ethers include tetrahydrofuran, alkyltetrahydrofuran, dialkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolan, alkyl-1,3-dioxolan, 1,4-dioxolan and the like.

Examples of the chain ethers include 1,2-dimethoxyethane, 1,2-diethoxyethane, diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether. Examples can be given.

[0059]

[Example 1] A long aluminum foil having a thickness of 20 µm and a width of 200 mm was used as a current collector, and a coating liquid for an active material layer having the following composition was applied to both front and back surfaces, dried, and dried. An active material layer having an hourly coating amount of 250 g / cm ² was formed.
The obtained raw material had an active material layer having a width of 180 mm, and uncoated portions having a width of 10 mm were left on both side edges.

<Coating liquid for active material layer> Active material LiCoO ₂ : 85 parts by weight Conductive agent Graphite: 8 parts by weight Binder polyvinylidene fluoride resin: 7 parts by weight Solvent N-methyl-2-pyrrolidone : Appropriate amount so that the solid content of the coating solution is 62% by weight

The raw material is cut in the longitudinal direction and divided into two equal parts.
An intermediate product of an electrode plate having an active material layer having a total width of 100 mm, a width of 90 mm, and an uncoated portion having a width of 10 mm on one side edge was obtained. In the uncoated portion of the obtained intermediate product, cuts having a length of 10 mm orthogonal to the longitudinal direction were formed at intervals of 20 mm. Thereafter, a linear pressure of 0.degree.
Pressing was performed at 5 ton / cm to obtain an electrode plate with little deformation.

[0062]

As described above, according to the present invention,
When manufacturing an electrode plate, it is possible to omit the trimming step of cutting off a strip-shaped uncoated portion that is inevitably left on the peripheral edge of the raw material of the electrode plate, so that the electrode plate is manufactured efficiently. Can be. In particular, productivity can be greatly enhanced by incorporating the manufacturing method of the present invention into continuous mass production of electrode plates using a long current collector.

The electrode plate of the present invention has a higher uniformity of a coating film than an electrode plate produced by applying a pattern by controlling the movement of a coater head in a complicated manner. Further, in the present invention, since the coating film is not scraped off with a spatula or the like, powder is hardly dropped from the edge of the coating film.
Therefore, the electrode plate of the present invention has excellent quality.

Further, according to the present invention, since the uncoated portion at the peripheral edge of the raw material of the electrode plate is cut beforehand and then pressed, only the portion where the active material layer is formed is pressed. Even if it is extended, uneven stress is released, and the electrode plate is hardly deformed. Therefore, by using the electrode plate of the present invention, the electrode plate can be densely wound without distortion at the time of assembling the battery, and a battery having good winding state and a high active material filling rate can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an electrode plate of the present invention.

FIG. 2 is a diagram schematically showing an AA cross section of the electrode plate of FIG. 1;

FIG. 3 is a plan view showing another example of the electrode plate of the present invention.

FIG. 4 is a view schematically showing a BB cross section of the electrode plate of FIG. 3;

FIG. 5 is a plan view showing another example of the electrode plate of the present invention.

FIG. 6 is a view for explaining one step in manufacturing the electrode plate of FIG. 1;

FIGS. 7 (1) and 7 (2) are views for explaining one step in manufacturing the electrode plate of FIG. 1;

FIG. 8 is a view for explaining one step in manufacturing the electrode plate of FIG. 3;

9 (1) and 9 (2) are views for explaining one step in manufacturing the electrode plate of FIG. 3;

FIG. 10 is a view for explaining one step in manufacturing the electrode plate of FIG. 5;

11 (1) and 11 (2) are views for explaining one step in manufacturing the electrode plate of FIG. 5;

FIG. 12 is a diagram illustrating one step of a conventional method for manufacturing an electrode plate by controlling the movement of a bar coater.

FIG. 13 is a diagram illustrating one step of a conventional method for manufacturing an electrode plate by controlling the movement of a bar coater.

FIG. 14 is a diagram illustrating one step of a conventional method for manufacturing an electrode plate by controlling the movement of a bar coater.

FIG. 15 is a view illustrating one step of a conventional method for manufacturing an electrode plate by scraping off an active material layer with a spatula or the like.

FIG. 16 is a view for explaining one step of a conventional method of manufacturing an electrode plate by scraping an active material layer with a spatula or the like.

FIG. 17 is a diagram showing deformation of an electrode plate by press working.

[Explanation of symbols]

 2: current collector 3: active material layer 4: uncoated portion having a unique function 5: unnecessary uncoated portion 6 (6a, 6b, 6c ...): cut

Claims (6)

[Claims] 1. A current collector, an active material layer containing at least an active material and a binder and provided on the current collector, and exposing at least one end or one side edge of the current collector in a strip shape. A non-aqueous electrolytic product comprising at least an uncoated portion formed by press working an intermediate product having a plurality of cuts intersecting the flow direction and being arranged side by side in the uncoated portion. Electrode plate for liquid secondary battery. 2. The gap between the cuts is 10 to 60 mm.
The electrode plate for a non-aqueous electrolyte secondary battery according to claim 1, wherein 3. The electrode plate for a non-aqueous electrolyte secondary battery according to claim 1, wherein the current collector has a thickness of 10 to 50 μm. 4. A current collector, an active material layer containing at least an active material and a binder and provided on the current collector, and exposing at least one end or one side edge of the current collector in a strip shape. An intermediate product for an electrode plate, comprising at least an uncoated portion formed by being formed, wherein the uncoated portion has a plurality of cuts crossing the flow direction thereof and being arranged side by side with each other. 5. An active material coating liquid containing at least an active material and a binder is applied on the current collector so that at least a part of the peripheral portion of the current collector remains in a strip shape. Then, an intermediate product of the electrode plate is prepared, and a plurality of cuts intersecting with the flow direction and being arranged side by side are formed in the uncoated portion left in a band shape at least at a part of the peripheral portion of the intermediate product. A method for producing an electrode plate for a non-aqueous electrolyte secondary battery, comprising press-working the intermediate product. 6. An active material coating liquid containing at least an active material and a binder is left on a long current collector such that at least both side edges of the current collector are exposed in a strip shape. 6. An intermediate product of an electrode plate provided with a strip-shaped uncoated portion on at least one side edge after forming an active material layer by coating on an active material layer. 3. The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to item 1.