JP4619465B2 - Method for producing electrode plate for non-aqueous electrolyte secondary battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an electrode plate for a nonaqueous electrolyte secondary battery represented by a lithium ion secondary battery (hereinafter sometimes referred to as “electrode plate”), and an electrode plate produced by the method. More specifically, the present invention relates to a method for efficiently producing an electrode plate having a non-coated portion where a current collector is exposed. The present invention also relates to an electrode plate that is excellent in the positional accuracy and dimensional accuracy of the active material layer and the non-coated portion, and also excellent in the adhesion of the active material layer.
[0002]
[Prior art]
In recent years, electronic devices and communication devices are rapidly becoming smaller and lighter, and secondary batteries used as power sources for driving these devices are also required to be smaller and lighter. For this reason, in place of the conventional alkaline storage battery, a non-aqueous electrolyte secondary battery having a high energy density and a high voltage, typically a lithium ion secondary battery has been proposed.
[0003]
Regarding the positive and negative electrode plates that greatly affect the performance of the secondary battery, the electrode plates are rolled into the battery by thinning the electrode plate to extend the charge / discharge cycle life and to increase the energy density. It has been proposed to increase the area of the electrode plate.
[0004]
For example, in Japanese Patent Application Laid-Open Nos. 63-10456 and 3-285262, positive electrode active material powders such as metal oxides, sulfides and halides, conductive materials and binders (binders) are appropriately wetted. A paste-like active material coating solution is prepared by dispersing or dissolving in an agent (hereinafter referred to as a solvent), and a current collector made of metal foil is used as a base, and the coating liquid is applied onto the base and a positive electrode A positive electrode obtained by forming an active material layer (also referred to as a negative electrode active material layer when a negative electrode coating liquid is applied on a substrate, and simply referred to as an active material layer if the positive electrode and the negative electrode are not particularly distinguished) An electrode plate is disclosed. In this positive electrode plate, as a binder, for example, a fluorine-based resin such as polyvinylidene fluoride, a silicone-acrylic copolymer, a styrene-butadiene copolymer, or the like is used.
[0005]
On the other hand, the negative electrode plate is prepared by adding a binder material dissolved in a suitable wetting agent (solvent) to a negative electrode active material such as carbon to prepare a paste-like active material coating solution. It is obtained by coating on the electric body. Moreover, in order to improve the density of the coating film with respect to a collector, or to improve the adhesiveness of a coating film, a press process is normally given.
[0006]
The binder for preparing the active material coating solution in the above-mentioned coated electrode plate is chemically stable with respect to the non-aqueous electrolyte solution, does not elute in the electrolyte solution, and does not dissolve in any solvent. It must be dissolved and can be applied thinly on the substrate.
[0007]
Furthermore, the coated and dried active material layer has flexibility so as not to be peeled off, dropped off, cracked or the like in the battery assembly process, and has excellent adhesion to the current collector. Is required. JP-A-7-296802 discloses a method for producing an electrode plate for a negative electrode with good adhesion of an electrode layer by forming an electrode layer after previously applying a silane coupling agent to the surface of a current collector. Is described.
[0008]
[Problems to be solved by the invention]
Here, the electrode plate usually has a non-coated portion where no active material layer is desired to be provided, such as a portion to which a terminal for taking out current is attached and a boundary portion between adjacent active material layers. The pattern of the non-coated part is arbitrarily determined according to the battery design. The method for producing the non-coated part includes a method of directly forming a pattern of the coated part and the non-coated part by applying an electrode coating liquid onto the current collector while mechanically controlling the coater head. There is a method of forming an uncoated portion by forming a coated film on the entire surface of the current collector and then partially peeling the coated film by a mechanical means such as a spatula.
[0009]
In the case of the former method, the start and stop of discharge of the active material coating liquid from the coater head may be repeated while moving the coater head and / or current collector according to the pattern of the coated part or non-coated part. Alternatively, whenever the coating operation reaches the boundary between the coated part and the non-coated part, the movement of the coater head and / or the current collector is stopped and restarted, the coater head is detached from the coated surface, and reappears. The operation such as stopping and restarting the discharge of the coating liquid is performed in synchronization with each other. By performing intermittent coating by mechanical control of such a coater head, for example, an active material layer having a length of 600 mm and an uncoated portion having a length of 50 mm are formed on the surface of a long current collector having a predetermined width. An original sheet of electrode plates provided alternately and repeatedly is created.
[0010]
However, as the coating speed is increased, it becomes difficult to synchronize the mechanical control of the coater head with the coating speed, and a pattern in which the coating part and the non-coating part are alternately repeated is accurately formed. I can't. In particular, when it is desired to intermittently repeatedly provide a non-coated portion having a relatively small area in the coated portion, it is extremely difficult to accurately form the pattern of the non-coated portion at a high coating speed. . As another problem, if the coater head is controlled in synchronism with a very high coating speed, the local coating amount slightly increases at each discharge start position and discharge stop position, and the active material layer has a slight excess. The edge is raised. As a result, the thickness of the active material layer becomes non-uniform, and it becomes difficult to wind up the electrode plate cleanly. If the coating speed is not increased so much, the above problem does not occur, but this does not increase the productivity of the electrode plate.
[0011]
The coater head can be mechanically controlled as a method for applying a desired pattern. For example, the coater head is mechanically controlled in addition to the coating method such as slot die coating, slide die coating, and comma reverse coating. For example, a coating method such as gravure coating or gravure reverse coating is also known. However, a method in which the coater head is not mechanically controlled is suitable for forming a thin coating layer, but is not suitable for the purpose of forming a relatively thick coating layer such as an active material layer. For these reasons, conventionally, although the productivity is not so good, the active material layer and the non-coated portion are formed by a coating method in which the coater head is mechanically controlled.
[0012]
On the other hand, in the case of the latter method, there is a problem that the patterning accuracy is not high, and further, it is difficult to smooth the edge of the active material layer, so that powder falls off from the edge. Furthermore, in order to prevent spontaneous separation, dropping and cracking of the active material layer from the current collector during battery assembly and charging / discharging, the active material layer is preliminarily coated with a coupling agent. When the adhesiveness to the material layer is increased, the peeling operation for forming the non-coated portion becomes difficult. As a result, the work time for peeling or the number of times the work is repeated increases, and the productivity of the electrode plate deteriorates.
[0013]
The present invention has been accomplished in view of the above circumstances. A first object of the present invention is to provide an electrode plate manufacturing method capable of accurately and efficiently forming an active material layer having a desired pattern and a non-coated portion on the surface of a current collector. It is in.
[0014]
A second object of the present invention is to provide an electrode plate having high positional accuracy between the active material layer and the non-coated portion and having excellent adhesion of the active material layer to the current collector.
[0015]
[Means for Solving the Problems]
By utilizing an adhesive such as a coupling agent, the present inventors can accurately and efficiently form an active material layer having a desired pattern and a non-coated portion on the current collector surface. I found it. In addition, the obtained electrode plate had not only high positional accuracy between the active material layer and the non-coated portion, but also the adhesion of the active material layer to the current collector was good due to the presence of an adhesive. The present invention has been accomplished based on such knowledge.
[0016]
The first method for achieving the above object is to provide an active material layer containing at least an active material and a binder on a current collector, and a non-coated portion having no active material layer. A method of manufacturing an electrode plate for a water electrolyte secondary battery, the step of forming an adhesive layer by applying an adhesive to a portion of the current collector surface where an active material layer is to be provided, and the formation of the adhesive layer Thereafter, the active material layer coating composition containing at least the active material and the binder is applied to the surface of the current collector on the side on which the adhesive layer is formed to form an active material layer; And a step of peeling off a portion of the active material layer where it is desired to provide the non-coated portion after the material layer is formed. In the first method, before applying the coating composition for the active material layer, a release agent layer may be formed by applying a release agent to a portion where the non-coated portion of the current collector surface is to be provided. Good.
[0017]
A second method for achieving the above object is to provide an active material layer containing at least an active material and a binder on a current collector, and a non-coated portion having no active material layer. A method of manufacturing an electrode plate for a water electrolyte secondary battery, the step of applying a release agent to a portion of the current collector surface where an uncoated part is to be provided to form a release agent layer, and a release agent layer Before or after the formation, a step of applying an adhesive to the surface of the current collector on which the release agent layer is formed to form an adhesive layer, and after forming the adhesive layer and the release agent layer, these layers are A step of applying an active material layer coating composition containing at least an active material and a binder to the surface of the current collector formed to form an active material layer; and after forming the active material layer, And a step of peeling the active material layer of the portion where the non-coated portion is to be provided together with the release agent layer.
[0018]
In the present invention, instead of coating the active material layer coating composition itself in a predetermined pattern, an adhesive or a release agent is applied in a predetermined pattern. Since the active material layer is relatively thick, it cannot be applied in a desired pattern unless the coater head is mechanically controlled. In contrast, the adhesive has properties that are easier to apply than the coating composition for the active material layer, and the required coating thickness is thin, so that the mechanical control of the coater head is not performed. It can be applied to a desired pattern. Therefore, the coating can be performed accurately at a high speed.
[0019]
Also, the release agent is applied only to the part where the non-coated part is to be provided, and the coating area is much smaller than the coating composition for the active material layer, so even if the coating speed is increased, the coater head There is room to control mechanically. Therefore, in this case as well, it can be applied at a high speed and in an accurate pattern.
[0020]
In the present invention, in the portion where the active material layer on the surface of the current collector is to be provided, an adhesive layer is interposed between the current collector and the active material layer to increase the adhesion of the active material layer. In a portion where an uncoated portion on the surface of the electric body is desired, an active material layer is directly formed on the current collector, or a release agent layer is interposed between the two to reduce the adhesion. Therefore, comparing the part where the active material layer on the current collector surface is to be provided and the part where the non-coated part is desired is compared, there is a difference in the adhesion of the active material layer, so the peeling process does not take time and the edge of the pattern Can be formed sharply.
[0021]
As described above, according to the present invention, the active material layer having a desired pattern and the non-coated portion can be accurately and efficiently formed on the surface of the current collector. In addition, the obtained electrode plate has a sharp pattern of the active material layer and the non-coated portion, and high positional accuracy. In addition, the adhesion between the current collector and the active material layer is excellent.
[0022]
The adhesive is appropriately selected according to the material of the current collector. When using a copper foil current collector, it is preferable to apply an adhesive containing a coupling agent, carboxylic acid or sulfonic acid as an adhesive. Particularly preferred adhesives are silane coupling agents whose terminal groups are amino groups and oxalic acid.
[0023]
As the release agent for forming the release agent layer, it is preferable to use a thermoplastic resin selected from polyvinylidene fluoride, polyethylene or a derivative thereof, polypropylene or a derivative thereof. As the release agent, a thermoplastic resin having a melting point of 100 to 250 ° C. and a melt viscosity of 100 to 50,000 cps is also preferably used.
[0024]
In the active material layer peeling step, the active material layer where the non-coated portion is to be provided may be scraped off with a spatula or the like, but at least the surface of the active material layer where the non-coated portion is desired to be provided It is possible to work efficiently by attaching and peeling the release sheet. Further, peeling may be performed after at least a portion of the active material layer where the non-coated portion is to be provided is impregnated with a heat-meltable material such as wax and solidified. There is a difference in the adhesion of the active material layer between the portion where the active material layer is to be provided, that is, the portion where the active material layer is to be left, and the portion where the non-coated portion is provided, that is, the portion where the active material layer is to be removed. Therefore, even in such a method, only a desired portion of the active material layer can be selectively peeled off.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to preferred embodiments. In the present invention, the adhesion to the active material layer on the surface of the current collector is improved using an adhesive such as a coupling agent only for the portion where the active material layer is to be provided, and then the active material layer is Then, the active material layer of a relatively weak adhesion is selectively peeled off to form an active material layer having a predetermined pattern and an uncoated portion.
[0026]
In the first method according to the present invention, an adhesive such as a coupling agent is applied to the surface of the current collector in a predetermined pattern in advance, and then the active material layer coating composition is entirely applied. Apply. An example of the first method is shown in FIG. In the method of FIG. 1, first, an adhesive such as a coupling agent is applied to a portion where the active material layer on the surface of the current collector 2 is to be provided, and dried or solidified as necessary to form an adhesive layer 3. Form. Next, the active material layer coating composition is applied to the entire surface of the current collector on which the adhesive layer 3 is formed, and dried or solidified as necessary to form the active material layer 4. . Thereafter, by peeling off only the portion of the active material layer where the non-coated portion is desired to be formed by a method such as using a peeling sheet 6, an electrode plate 101A having an active material layer 4a having a predetermined pattern and the non-coated portion 5 is obtained. It is done. The portion of the active material layer 4 where the active material layer is to be provided has high adhesion because the adhesive layer 3 is interposed. On the other hand, since the part which wants to provide a non-coating part among the active material layers 4 does not interpose an adhesive bond layer, its adhesiveness is low compared with the part in which the adhesive bond layer interposes. Therefore, it is possible to easily peel only the portion of the active material layer where it is desired to provide the non-coated portion. Note that the active material layer may be formed on both surfaces of the current collector.
[0027]
The active material layer where the non-coated portion is desired to be provided may be peeled off using a spatula or the like, but can be peeled off using the peeling sheet 6. When it is desired to use the method of FIG. 1, the adhesive strength of the release sheet 6 to the active material layer 4 is higher than the adhesive strength between the two when the active material layer 4 is directly formed on the surface of the current collector 2, and The active material layer 4 is adjusted so as to be lower than the adhesive force between the two when the active material layer 4 is formed via the adhesive layer 3. Then, when the release sheet is applied to the entire surface of the active material layer 4 or at least the surface of the active material layer where the non-coated portion is to be provided and then peeled off again, the adhesive layer 3 is interposed. Since the active material layer 4 in the portion is strongly fixed to the current collector 2, it is separated at the boundary between the active material layer 4 and the release sheet 6, while in the portion where the adhesive layer 3 is not interposed, the current collector is separated Since the adhesive force between the body 2 and the active material layer 4 is weak, it is separated at the boundary between them. As a result, a portion of the active material layer where the non-coated portion is to be provided can be selectively peeled off.
[0028]
In the first method of the present invention, instead of coating the active material layer coating composition itself in a predetermined pattern, the adhesive is applied in a predetermined pattern. When the adhesive and the coating composition for active material layer are compared, the adhesive has properties that are easier to apply than the coating composition for active material layer. In addition, since the adhesive layer is much thinner than the active material layer, it can be applied in a desired pattern by a coating method that does not require mechanical control of the coater head, such as gravure coating or gravure reverse. Can be crafted. Therefore, it is possible to apply the adhesive at a higher speed and more accurately when the adhesive is applied in a predetermined pattern than when the active material layer coating composition itself is applied in a predetermined pattern.
[0029]
When the coating composition for the active material layer is coated thickly while mechanically controlling the coater head, there is a problem that the edge of the active material layer is likely to rise, but in the first method, the coater A coating method that does not require mechanical control of the head can be used, and since the adhesive layer is thin, the end of the coating layer does not rise.
[0030]
Furthermore, in the first method, since the adhesion to the active material layer is increased only for the portion of the current collector surface where the active material layer is to be provided, not only the active material layer can be prevented from spontaneously peeling, falling off and cracking, Compared with the case where the entire surface of the current collector is improved in adhesion to the active material layer, the peeling work does not take time.
[0031]
Another example of the first method is shown in FIG. In the method of FIG. 2, first, an adhesive layer 3 is formed by applying an adhesive such as a coupling agent to a portion where the active material layer on the surface of the current collector 2 is to be provided. Next, a release agent is applied to a portion of the current collector 2 where a non-coated portion is to be provided to form a release agent layer 7. Note that the pattern of the adhesive layer 3 may be formed after the pattern of the release agent layer 7 is formed first. Next, the active material layer coating composition is applied to the entire surface of the current collector on which the adhesive layer 3 and the release agent layer 7 are formed to form the active material layer 4. Then, if only the part of the active material layer where the non-coated portion is desired to be formed is peeled off by a method such as using a peeling sheet, an electrode plate 101B having an active material layer 4a having a predetermined pattern and the non-coated portion 5 is obtained. The adhesion between the current collector 2 and the release agent layer 7 is weaker than the adhesion when the active material layer 4 is directly formed on the current collector 2. Therefore, the part of the active material layer in which the release agent layer 7 is interposed can be separated more easily than when the release agent layer is not formed by separating at the interface between the current collector 2 and the release agent layer 7. .
[0032]
In the second method according to the present invention, an adhesive such as a coupling agent is applied to the entire surface of the current collector, and a release agent is applied in a predetermined pattern before or after the adhesive is applied. Then, the active material layer coating composition is applied over the entire surface. An example of the second method is shown in FIG. In the method of FIG. 3, first, an adhesive such as a coupling agent is applied to the entire surface of the current collector 2 to form the adhesive layer 3. Next, a release agent is applied to a portion where the non-coated portion on the surface of the current collector on which the adhesive layer 3 is formed is provided to form the release agent layer 7. Next, the active material layer coating composition is applied to the entire surface of the current collector on which the adhesive layer 3 and the release agent layer 7 are formed to form the active material layer 4. When each layer is formed by such a method, the active material layer 4 is firmly fixed to the current collector 2 through the adhesive layer 3 in the portion where the active material layer on the surface of the current collector is to be provided. The adhesive force between the adhesive layer 3 and the release agent layer 7 is weak in the portion where it is desired to provide. Therefore, the active material layer of the part where the non-coated portion is desired to be formed can be easily peeled together with the release agent layer 7 by a method such as using the peeling sheet 6, and the active material layer 4 a having a predetermined pattern and the non-coated portion An electrode plate 101C having the part 5 is obtained. The adhesive layer 3 remains in the non-coated portion 5 of the electrode plate 101C, but the adhesive layer is about 0.1 g / m. ² If it is formed as thin as possible, it will not affect the current-carrying performance.
[0033]
Another example of the second method is shown in FIG. In the method of FIG. 4, first, the release agent layer 7 is formed by applying a release agent to a portion of the surface of the current collector 2 where the uncoated portion is to be provided. Next, an adhesive such as a coupling agent is applied to the entire surface of the current collector on the side where the release agent layer 7 is formed to form the adhesive layer 3. Next, the active material layer coating composition is applied to the entire surface of the current collector on which the release agent layer 7 and the adhesive layer 3 are formed to form the active material layer 4. Even when each layer is formed by this method, as in the previous example of the second method, the active material layer 4 is interposed by the adhesive layer 3 in the portion where the active material layer on the surface of the current collector is to be provided. 2 firmly adheres. On the other hand, the adhesion between the current collector 2 and the release agent layer 7 is weak in the portion where the non-coated portion on the current collector surface is to be provided. Accordingly, the active material layer 4a having a predetermined pattern can be easily peeled off along with the release agent layer 7 in the active material layer and the adhesive layer where the non-coated portion is to be formed by a method such as using the release sheet 6. Thus, an electrode plate 101D having the non-coated portion 5 is obtained.
[0034]
In the second method of the present invention, instead of applying the active material layer coating composition itself in a predetermined pattern, the release agent is applied in a predetermined pattern. If the coating agent for the active material layer is coated by a method that does not require mechanical control of the coater head to apply the release agent, the coating composition for the active material layer is applied faster than when coated by the mechanical control method of the coater head. And it can coat correctly. Moreover, even when the release agent is applied by a method of mechanically controlling the coater head, the release agent is only applied to the portion where the non-coated portion is to be provided, and is more effective than the active material layer coating composition. Since the coating area is much smaller, it can be applied with high accuracy even if the coating speed is increased. Therefore, also in the case of the second method, as in the first method, it can be applied at a high speed and in an accurate pattern. Even if the end of the release agent layer is raised because the release agent is applied by a method of mechanically controlling the coater head, there is no problem because the release agent layer is removed in the release step. The second method is the same as the first method in that the adhesion to the active material layer is selectively enhanced only for the portion of the current collector surface where the active material layer is to be provided. Compared with the case where the adhesiveness to the active material layer is increased over the entire surface, it takes less time for the peeling operation.
[0035]
As described above, according to the present invention, coating can be performed at a high speed and in an accurate pattern, and the subsequent stripping process does not take time. Therefore, an active material having a desired pattern on the surface of the current collector is obtained. The material layer and the non-coated portion can be formed accurately and efficiently. Further, the obtained electrode plate has high positional accuracy between the active material layer and the non-coated portion, and is excellent in adhesion between the current collector and the active material layer. There is no bulge at the edge of the active material layer.
[0036]
Next, each material constituting the electrode plate for a nonaqueous electrolyte secondary battery of the present invention and a secondary battery using the electrode plate of the present invention will be described.
[0037]
[Current collector]
As the current collector 2 as the substrate, a metal foil is usually used, an aluminum foil is preferably used as the positive electrode plate, and a copper foil is preferably used as the negative electrode plate. The thickness of these metal foils is usually about 5 to 30 μm.
[0038]
[Adhesive layer]
The adhesive layer is formed on the surface of the current collector in order to improve the adhesion between the current collector and the active material layer. As the adhesive for forming the adhesive layer, for example, various coupling agents such as silane, titanate, and aluminum can be used.
[0039]
Examples of silane coupling agents include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltri. Methoxysilane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl-γ-aminopropyltrimethoxysilane / hydrochloride, γ-glycidoxypropyltri Methoxysilane, aminosilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysila Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, γ-chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxy Examples include silane, methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane.
[0040]
Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tridodecyl benzene sulfonyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridecyl phosphite). ) Titanate, tetra (2,2-diallyloxymethyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyldimethacryliso Stearoyl titanate, isopropyl isostearoyl diacryl titanate, Sopuropirutori (dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tri (N- aminoethyl-aminoethyl) titanate, dicumyl phenyloxy acetate titanate, diisostearoyl ethylene titanate.
[0041]
Examples of the aluminum coupling agent include acetoalkoxyaluminum diisopropylate.
[0042]
When copper foil is used as the current collector, carboxylic acid or sulfonic acid is also effective as an adhesive in addition to the various coupling agents as described above. Carboxylic acid and sulfonic acid may have a functional group or substituent other than the carboxyl group or the sulfone group as a side chain and / or as a part of the main chain. The carboxylic acid and sulfonic acid may be a polymer. Preferred adhesives for enhancing the adhesion of the copper foil current collector are silane coupling agents having amino groups, mercapto groups, or vinylbenzylaminoethyl groups as terminal groups, and oxalic acid. Of these, silane coupling agents having an amino group as a terminal group and oxalic acid are particularly preferable.
[0043]
The adhesive layer is formed by applying a solution prepared by dissolving one or more adhesives in water, an organic solvent, or a water / organic solvent mixture to the surface of the current collector and drying. Can do.
[0044]
When using a coupling agent as an adhesive, the coupling agent is usually dissolved in an organic solvent or a water / organic solvent mixture to obtain a coating solution. In order to promote hydrolysis of the coupling agent, the pH of the coating solution may be adjusted to 3-5. Moreover, you may add hydrochloric acid, an acetic acid, etc. as a catalyst for hydrolysis of a coupling agent, for example. Furthermore, in order to accelerate the dehydration reaction between the coupling agent and the current collector surface, the coupling agent may be applied on the current collector and then heated at a temperature of 120 to 130 ° C. Examples of the solvent for dissolving the coupling agent include methanol, ethanol, isopropyl alcohol, toluene, benzene, acetone, tetrahydrafuran, and cellosolve methyl.
[0045]
When carboxylic acid or sulfonic acid is used as the adhesive, the carboxylic acid or sulfonic acid is usually dissolved in an organic solvent to form a coating solution. In order to accelerate the drying of the coating solution, the coating layer may be heated at a temperature of 120 to 130 ° C. after coating. Examples of the organic solvent for dissolving carboxylic acid or sulfonic acid include methanol, methanol, isopropyl alcohol, toluene, benzene, acetone, N-methylpyrrolidone, and the like.
[0046]
In the present invention, the adhesive is applied only to the portion where the active material layer on the current collector surface is to be provided, so that only the portion where the active material layer is desired to be provided on the current collector surface is formed between the current collector and the active material layer. The adhesion between them can be increased. In this method, the adhesive must be applied to the surface of the current collector in a predetermined pattern, but the coating liquid for the adhesive layer is more coated than the coating liquid for the active material layer. In addition, the adhesive layer is much thinner than the active material layer, so coating methods that do not require mechanical control of the coater head, such as gravure coating and gravure reverse coating, etc. By this method, a desired pattern can be applied. Therefore, when the adhesive is applied in a predetermined pattern, it can be applied at a higher speed and more accurately than when the active material layer itself is applied in a predetermined pattern.
[0047]
As a method of applying an adhesive in a desired pattern, a method in which mechanical control of the coater head is not performed, for example, gravure coating or gravure reverse coating, and a method in which mechanical control of the coater head is performed, for example, slot die coating Either a slide die coat or a comma reverse coat may be applied, but the former is preferable because of high productivity.
[0048]
In addition, the release agent is applied to the portion where the non-coated portion of the current collector surface is to be provided, and the adhesive surface is also applied to the entire surface of the current collector before or after that. Adhesiveness between the current collector and the active material layer can be improved only for the portion where the active material layer is to be provided. In the case of this method, it is not necessary to apply the adhesive in a specific pattern, so any coating method may be applied. Specifically, for example, current collection by a method such as gravure coating, gravure reverse coating, roll coating, Mayer bar coating, blade coating, knife coating, air knife coating, slot die coating, slide die coating, dip coating, nozzle coating, etc. An adhesive layer can be formed on the entire body surface.
[0049]
The coating amount of the adhesive layer thus formed is 0.001 to 5 g / m when dried. ² The degree is preferred. However, when the adhesive layer remains in the non-coated portion after the active material layer is peeled off as in the method shown in FIG. 3, the amount of adhesive applied so as not to adversely affect the current-carrying performance of the electrode plate. 0.1 g / m ² It is preferable to adjust to the following.
[0050]
[Release layer]
When the release agent layer is formed in a portion to be a non-coated portion on the surface of the current collector, and an active material layer is formed thereon, the adhesive force of the active material layer in this portion is weakened and is easily peeled off.
[0051]
The release agent for forming the release agent layer is inferior in adhesion to the current collector when the release agent is directly applied to the current collector, and easily at the boundary between the current collector and the release agent layer. It must be peelable. In addition, when the release agent is applied after the adhesive is applied to the entire surface of the current collector, the release agent has poor adhesion to the adhesive layer, and the adhesive layer is separated from the release agent layer. It must be easy to peel off at the boundary.
[0052]
Specific examples of the release agent include polyvinylidene fluoride, polyethylene or a derivative thereof, a thermoplastic resin selected from polypropylene or a derivative thereof, and a mixture of these thermoplastic resins. Among these, select one with low adhesion to the coated surface. Preferred release agents include polyvinylidene fluoride, non-oxidation type low density type, non-oxidation type medium density type, non-oxidation type high density type, oxidation type low density type, oxidation type medium density type, oxidation type high density type, non-oxidation type Examples include various types of polyethylene and polypropylene such as polar type, polar type, and fine powder type.
[0053]
A release agent that exhibits fluidity by heating is suitable. When polyethylene, polypropylene, or a derivative thereof is used as the release agent, the melting point is preferably about 100 to 250 ° C., and if the melting point is particularly preferably about 120 to 170 ° C., it is soft at room temperature. Therefore, it is difficult to handle the release agent, the productivity is inferior, and the release agent layer melts when an active material layer is formed on the release agent layer and dried. Moreover, when melting | fusing point is too high, it is uneconomical in energy and will invade the collector which is a base material at the time of coating of release agent. The melt viscosity of polyethylene, polypropylene or derivatives thereof is usually about 100 to 50,000 cps, preferably about 400 to 6,000 cps. If the melt viscosity is too high, it is uneconomical in terms of energy. On the other hand, if the melt viscosity is too low, when it is melted, it spreads too much on the current collector surface, making patterning difficult.
[0054]
In order to form the release agent layer in a predetermined pattern, the release agent may be dissolved or dispersed in an appropriate solvent and applied to the surface of the current collector. When the release agent is polyvinylidene fluoride, it is preferable to prepare a coating solution by dissolving and dispersing in N-methyl-2-pyrrolidone and then coating. The release agent melted by heating may be applied to the surface of the current collector. The coating liquid or melt of the release agent is, for example, general gravure coating, gravure reverse coating, roll coating, Mayer bar coating, blade coating, knife coating, air knife coating, slot die coating, slide die coating, nozzle coating, etc. Can be applied in a predetermined pattern. The most appropriate coating method may be selected in consideration of conditions such as the melting property of the release agent and the required coating thickness.
[0055]
When the release agent layer is relatively thin, it can be applied in a predetermined pattern by a method that does not require mechanical control of the coater head, such as gravure coating or gravure reverse coating. If the coating agent for the active material layer is coated by a method that does not require mechanical control of the coater head to apply the release agent, the coating composition for the active material layer is applied faster than when coated by the mechanical control method of the coater head. And it can coat correctly.
[0056]
On the other hand, when the release agent layer is relatively thick, it is necessary to apply the coating composition for the active material layer by a method in which the coater head is mechanically controlled. Even when the release agent is applied by the method of mechanically controlling the coater head, the release agent is only applied to the portion where the non-coated portion is to be provided, and much more than the coating composition for the active material layer. Since the coating area is small, it can be applied accurately even if the coating speed is increased. Therefore, it can be applied at a high speed and in an accurate pattern. Moreover, even if the end of the release agent layer is raised because the release agent is applied by a method of mechanically controlling the coater head, there is no problem because the release agent layer is removed in the release step.
[0057]
The thickness of the release agent layer thus formed is preferably about the same as or slightly less than the thickness of the active material layer during drying.
[0058]
[Active material layer]
The active material layer 4 contains at least an active material and a binder. The active material includes a positive electrode active material and a negative electrode active material. As the positive electrode active material, for example, LiCoO ₂ , LiNiO ₂ Or LiMn ₂ O _Four Lithium oxide such as TiS ₂ , MnO ₂ , MoO _Three Or V ₂ O _Five And the like chalcogen compounds. 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 metallic lithium or a lithium alloy, or a carbonaceous material such as graphite, carbon black, or acetylene black is preferably used. In particular, 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.
[0059]
The positive electrode active material and the negative electrode active material have a particle diameter in the range of 1 to 100 μm and an average particle diameter of about 10 μm in order to uniformly disperse these active materials in the coating layer Is preferred.
[0060]
Examples of the binder (binder) include thermoplastic resins, more specifically polyester resins, polyamide resins, polyacrylate resins, polycarbonate resins, polyurethane resins, cellulose resins, polyolefin resins, polyvinyl resins, and fluorine resins. Alternatively, polyimide resin or the like can be used. At this time, an acrylate monomer or oligomer into which a reactive functional group is introduced can be mixed in the binder. In addition, rubber-based resins, thermosetting resins such as acrylic resins and urethane resins, ionizing radiation curable resins composed of acrylate monomers, acrylate oligomers or mixtures thereof, and mixtures of the above various resins may be used. it can.
[0061]
An active material layer, a binder, and other components as necessary are mixed to prepare a coating composition. For example, an appropriately selected active material and a binder are put into an organic solvent such as toluene, methyl ethyl ketone, N-methyl-2-pyrrolidone or a mixture thereof, and a conductive agent is added as necessary. A coating solution is prepared by dissolving or dispersing with a disperser such as a homogenizer, ball mill, sand mill or roll mill. The blending ratio at this time is preferably such that the total amount of the active material and the binder is about 40 to 80 parts by weight when the total coating liquid is 100 parts by weight. Further, the mixing 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, the active material: binder is preferably about 5: 5 to 9: 1 (weight ratio), In the case of the negative electrode plate, the active material: binder is preferably about 8: 2 to 9: 1 (weight ratio). As the conductive agent, for example, a carbonaceous material such as graphite, carbon black, or acetylene black is used as necessary.
[0062]
The prepared coating solution is applied to an adhesive layer and, if necessary, a current collector in which a release agent layer is further formed in a predetermined pattern, and then dried to form an active material layer. Form.
[0063]
A method for applying the active material coating liquid is not particularly limited, but a method capable of forming a thick coating layer such as slot die coating, slide die coating, comma reverse coating, and the like is suitable. However, when the thickness required for the active material layer is relatively thin, it may be applied by gravure coating or gravure reverse coating. In the present invention, since it is not necessary to apply the active material coating liquid in a predetermined pattern, the coater head is mechanically controlled even when coating is performed by slot die coating, slide die coating, comma reverse coating, etc. There is no need to do.
[0064]
As a heat source in the drying process, hot air, infrared rays, microwaves, high frequencies, or a combination thereof can be used. You may dry with the heat which discharge | released the metal roller and metal sheet which support or press a collector in a drying process. In addition, after drying, the active material layer can also be obtained by irradiating an electron beam or radiation to cause a crosslinking reaction of the binder. Application and drying may be repeated a plurality of times. The thickness of the active material layer is usually 10 to 200 μm, preferably 50 to 170 μm when dried. Furthermore, it is preferable to age the obtained active material layer in a vacuum oven or the like to remove moisture in the active material layer.
[0065]
The uniformity of a coating film can be improved by pressing the obtained coating film using a metal roll, a heating roll, or a sheet press machine. Further, during the drying of the active material layer, the surface of the active material layer may be smoothed by lightly pressing a surface smooth film such as a polyethylene terephthalate film on the surface and peeling it again.
[0066]
[Peeling work]
After forming the active material layer on the current collector, the portion of the active material layer where the non-coated portion is to be provided is peeled off to complete the electrode plate of the present invention. Of the active material layer on the current collector, the part where the active material layer is to be left, that is, the part where the active material layer is to be provided is firmly fixed to the current collector through the adhesive layer. Since the portion where it is desired to peel off, that is, the portion where the non-coated portion is to be provided is formed directly on the current collector or via the peeling layer, the adhesive force is relatively weak. Therefore, the active material layer in the portion where the non-coated portion is to be provided can be easily peeled using the difference in adhesion, and a sharp and smooth boundary portion can be formed. When a release agent layer is interposed in a portion where the non-coating portion is to be provided, the difference in adhesion between the portion where the active material layer is desired to be left and the portion where the active material layer is desired to be peeled is increased, which makes peeling particularly easy.
[0067]
The active material layer where the non-coated portion is to be provided may be peeled off using a spatula or the like, but may be peeled off using a peeling sheet as shown in each drawing. By applying a release sheet with an appropriately adjusted adhesive force to the entire surface of the active material layer or at least the surface of the active material layer where the non-coated portion is to be provided, and then peeling it off again, Only the active material layer of the part where the part is to be provided is peeled off. When interposing the release agent layer in the part that should be the non-coated part, adjust the adhesion of each material so that the release agent layer can be peeled off at the current collector side interface and removed together with the active material layer. deep.
[0068]
As an example, a sheet having a heat sealing material layer formed on one side of a heat-resistant plastic film is used as the peeling sheet, and the peeling sheet is activated by facing the heat sealing material layer of the peeling sheet with the active material layer. Only the portion of the active material layer where the adhesive force is weak can be peeled off by stacking on the material layer, peeling off after thermocompression bonding.
[0069]
The portion of the active material layer that should be the non-coated portion may be removed after impregnating and solidifying a hot-melt material such as wax into the active material layer to form a mixture of the hot-melt material and the active material.
[0070]
[Nonaqueous electrolyte for secondary battery]
When producing a secondary battery using the electrode plate produced through each of the above steps, in order to remove moisture in the active material layer before moving to the battery assembly process, heat treatment, decompression treatment, etc. Is preferably performed in advance.
[0071]
When, for example, a lithium secondary battery is produced using this electrode plate, a nonaqueous electrolytic solution in which a solute lithium salt is dissolved in an organic solvent is used. Examples of the lithium salt include LiClO. _Four , LiBF _Four , LiPF ₆ , LiAsF ₆ Inorganic lithium salts such as LiCl, LiBr, or LiB (C ₆ H _Five ) _Four , LiN (SO ₂ CF _Three ) ₂ , LiC (SO ₂ CF _Three ) _Three , LiOSO ₂ CF _Three , LiOSO ₂ C ₂ F _Five , LiOSO ₂ C _Three F ₇ , LiOSO ₂ C _Four F ₉ , LiOSO ₂ C _Five F ₁₁ , LiOSO ₂ C ₆ F ₁₃ , LiOSO ₂ C ₇ F ₁₅ An organic lithium salt such as is used.
[0072]
Examples of the organic solvent for dissolving the lithium salt include cyclic esters, chain esters, cyclic ethers, chain ethers and the like. More specifically, examples of cyclic esters include propylene carbonate, butylene carbonate, γ-butyrolactone, vinylene carbonate, 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, γ-valerolactone, and the like.
[0073]
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, propionic acid alkyl ester, malon Examples include acid dialkyl esters and acetic acid alkyl esters.
[0074]
Examples of cyclic ethers include tetrahydrofuran, alkyltetrahydrofuran, dialkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, 1,4-dioxolane and the like.
[0075]
Examples of 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. Can do.
[0076]
【Example】
[0077]
[ reference Example 1]
(1) Preparation of coating liquid for active material layer
A negative electrode plate was prepared. A coating material having the following composition was stirred for 30 minutes using a planetary mixer (manufactured by Kodaira Seisakusho Co., Ltd.) to prepare a slurry-like coating liquid for a negative electrode active material layer.
[0078]
<Coating liquid for negative electrode active material layer>
・ Negative electrode active material Graphite powder: 85 parts by weight
-Binder Polyvinylidene fluoride in N-methyl-2-pyrrolidone solution (solid content 12%, KF # 1100, manufactured by Kureha Chemical Co., Ltd.): 125 parts by weight
-Dispersion medium N-methyl-2-pyrrolidone: 5 parts by weight
[0079]
(2) Application of adhesive layer
Using a long copper foil (TCU-copper foil, manufactured by Nihon Foil Co., Ltd.) with a thickness of 14 μm and a width of 320 mm as a current collector, a coating liquid for the adhesive layer having the following composition is gravure reverse on one side. Intermittent coating was performed with a coater to repeatedly form the coated portion. The width of the coated part was 300 mm and the length was 800 mm. The length of the uncoated part was 20 mm. After coating, the current collector was placed in a drying zone of 2 m in length and 100 ° C. at 20 m / min. And dried at a conveying speed of. The coating amount after drying of the adhesive layer is 0.1 g / m ² was.
[0080]
<Coating liquid 1 for adhesive layer>
Silane coupling agent γ- (2-aminoethyl) aminopropyltrimethoxysilane (SH6020, manufactured by Toray Dow Corning Co., Ltd.): 1 part by weight
・ Ethyl alcohol: 99 parts by weight
[0081]
(3) Formation of active material layer
Next, a negative electrode active material layer coating liquid prepared in advance was applied to the side of the current collector on which the adhesive layer was formed using a slot die coater, and then dried using an oven. Using a drying oven having a length of 8 m where the temperature can be locally changed, the temperature was sequentially set to 100 ° C., 120 ° C., 130 ° C., and 140 ° C. every 2 m. And the current collector was 4 m / min. And dried at a conveying speed of. The thickness of the active material layer after drying was 130 μm. After drying, the electrode plate was pressed with a roll press at a linear pressure of 150 kgf / cm, and the thickness of the active material layer was set to 80% of the thickness before pressing.
[0082]
(4) Peeling of active material layer
A 130 μm-thick polyethylene heat seal material (MORETECH 0238N, manufactured by Idemitsu Petroleum Corporation) was dry-laminated on a 25 μm-thick polyethylene terephthalate film to prepare a 155 μm-thick release sheet. This release sheet was overlaid on the electrode plate with its heat sealing material surface facing the active material layer. Then, a rectangular iron plate having a width of 300 mm and a length of 20 mm from the top of the release sheet is applied to the part where the adhesive layer is not formed at 170 ° C. and 2 kgf / cm. ² The film was pressed for 2 seconds under the conditions of After that, when the release sheet was peeled off, most of the active material layer was peeled off together with the release sheet in the part where the adhesive layer was not formed, but the powder of the active material layer was still slightly on the surface of the current collector. Was attached. Then, when the same thermocompression bonding was performed once again on the same part, the active material layer was completely removed and a clean current collector surface appeared. During peeling, the pattern shape did not spread or collapse. Moreover, the pattern of the formed non-coating part had a sharp and non-pouring edge.
[0083]
[ reference Example 2]
Except for using the adhesive layer coating liquid 2 having the following composition: reference In the same manner as in Example 1, intermittent coating was performed. The resulting adhesive layer is reference Although it has the same pattern as Example 1, it contains oxalic acid as an adhesive, and the coating amount after drying is 0.1 g / m. ² was.
[0084]
<Coating liquid 2 for adhesive layer>
・ Oxalic acid: 1 part by weight
N-methylpyrrolidone: 99 parts by weight
[0085]
afterwards, reference Using the same negative electrode active material coating solution as in Example 1, reference Coating was carried out in the same manner as in Example 1 to form an active material layer having a dry thickness of 130 μm. then, reference Using the same release sheet as in Example 1, reference The peeling operation was performed in the same manner as in Example 1.
[0086]
As a result reference Same as Example 1. That is, when the release sheet is peeled off, most of the active material layer is peeled off together with the release sheet in the part where the adhesive layer is not formed, but the powder of the active material layer is slightly applied to the surface of the current collector. Was attached. When the same thermocompression bonding was performed once again on the same part, the active material layer was completely removed and a clean current collector surface appeared. During peeling, the pattern shape did not spread or collapse. Moreover, the pattern of the formed non-coating part had a sharp and non-pouring edge.
[0087]
[ reference Example 3 ]
(1) Coating of release agent layer
Using a long copper foil (TCU-copper foil, manufactured by Nippon Foil Co., Ltd.) having a thickness of 14 μm and a width of 320 mm as a current collector, a coating liquid for a release agent layer having the following composition is gravure directly Intermittent coating was carried out with a coater, and a release agent layer pattern was repeatedly formed. The width of the coated part of the release agent layer was 300 mm and the length was 20 mm. The length of the uncoated part was 800 mm. After coating, the current collector was placed in a drying zone of 2 m in length and 100 ° C. at 10 m / min. And dried at a conveying speed of. The coating amount of the release agent layer after drying is 4 g / m ² was.
[0088]
<Coating liquid 1 for release agent layer>
・ Polyvinylidene fluoride: 6 parts by weight
・ N-methyl-2-pyrrolidone: 6 parts by weight
[0089]
(2) Formation of adhesive layer
reference Using the same adhesive layer coating solution as in Example 1, reference Intermittent coating was performed in the same manner as in Example 1, and an adhesive layer pattern was repeatedly formed on the surface of the current collector where no release agent layer was formed. The coated part of the adhesive layer had a width of 300 mm and a length of 800 mm, and the uncoated part had a length of 20 mm. That is, the release agent layer and the adhesive layer were formed to have a complementary relationship between a positive pattern and a negative pattern. The coating amount of the adhesive layer after drying is 0.1 g / m ² was.
[0090]
(3) Formation of active material layer
On the side of the current collector on which the release agent layer and adhesive layer are formed, reference Using the same negative electrode active material layer coating solution as in Example 1, reference Coating and drying were conducted in the same manner as in Example 1 to form an active material layer having a dry thickness of 130 μm.
[0091]
(4) Peeling of active material layer
reference The release sheet of Example 1 was overlaid on the electrode plate so that the heat sealing material surface faced the active material layer. Then, on the part where the release agent layer is formed, a rectangular iron plate having a width of 300 mm and a length of 20 mm from above the release sheet is 170 ° C., 2 kgf / cm. ² The film was pressed for 2 seconds under the conditions of Thereafter, when the peeling sheet was peeled off, the active material layer in the portion where the peeling sheet was pressure-bonded was completely peeled together with the peeling sheet, and a clean current collector surface appeared. During peeling, the pattern shape did not spread or collapse. Moreover, the pattern of the formed non-coating part had a sharp and non-pouring edge.
[0092]
[Reference example 4 ]
Except that the adhesive layer was formed first and then the release agent layer was formed reference Example 3 Apply and dry in the same way as reference Example 3 An adhesive layer, a release agent layer, and an active material layer having the same pattern and the same coating amount were formed. Since then reference Example 3 In the same manner as above, the part of the active material layer where the release agent layer was formed was peeled off using a peeling sheet. As a result, the active material layer in the portion where the release sheet was pressure bonded completely peeled off together with the release sheet, and a clean current collector surface appeared. During peeling, the pattern shape did not spread or collapse. Moreover, the pattern of the formed non-coating part had a sharp and non-pouring edge.

[0093]
[Comparative Example 1]
Except for the continuous application of the coupling agent coating solution to the surface of the current collector reference In the same manner as in Example 1, coating, drying and pressing were performed to prepare a negative electrode plate, and the active material layer was peeled off using a peeling sheet. However, it was able to peel only to the extent that the powder of the active material layer was slightly attached to the heat seal surface of the peeling sheet. When the same peeling operation was repeated nine times, a beautiful current collector surface finally appeared.
[0094]
[Comparative Example 2]
Except for the continuous application of oxalic acid coating solution to the surface of the current collector reference In the same manner as in Example 2, coating, drying and pressing were performed to produce a negative electrode plate, and the active material layer was peeled off using a peeling sheet. However, it was able to peel only to the extent that the powder of the active material layer was slightly attached to the heat seal surface of the peeling sheet. When the same peeling operation was repeated 10 times, a beautiful current collector surface finally appeared.
[0095]
[Comparative Example 3]
Other than not having an adhesive layer reference In the same manner as in Example 1, coating, drying and pressing were performed to prepare a negative electrode plate, and the active material layer was peeled off using a peeling sheet. However, the edge of the pattern of the obtained non-coated part was not sharp, and when the active material layer was peeled off, the pattern shape spread, powder falling from the edge part, and the like occurred.
[0096]
[Comparative Example 4]
Other than not having an adhesive layer reference In the same manner as in Example 2, coating, drying and pressing were performed to produce a negative electrode plate, and the active material layer was peeled off using a peeling sheet. However, the edge of the pattern of the obtained non-coated part was not sharp, and when the active material layer was peeled off, the pattern shape spread, powder falling from the edge part, and the like occurred.
[0097]
【The invention's effect】
As described above, according to the present invention, instead of coating the active material layer coating composition itself in a predetermined pattern, an adhesive or a release agent is applied in a predetermined pattern. It can be applied at high speed and accurately. In addition, there is a difference in the adhesion of the active material layer between the part where the active material layer is to be provided and the part where the non-coated part is provided, so that the peeling process does not take time and the pattern edge can be formed sharply. . Therefore, the active material layer having a desired pattern and the non-coated portion can be accurately and efficiently formed on the surface of the current collector. In addition, the obtained electrode plate has a sharp pattern of the active material layer and the non-coated portion, and high positional accuracy. In addition, the adhesion between the current collector and the active material layer is excellent. Further, the end of the active material layer does not rise.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an example of a method for producing an electrode plate of the present invention.
FIG. 2 is an explanatory view showing another example of the electrode plate manufacturing method of the present invention.
FIG. 3 is an explanatory view showing another example of the electrode plate manufacturing method of the present invention.
FIG. 4 is an explanatory view showing another example of the electrode plate manufacturing method of the present invention.
[Explanation of symbols]
2: Current collector
3: Adhesive layer
4: Active material layer
5: Non-coated part
6: Sheet for peeling
7: Release agent layer

Claims (9)

A method for producing an electrode plate for a non-aqueous electrolyte secondary battery, comprising an active material layer containing at least an active material and a binder on a current collector and a non-coated portion having no active material layer. There,
A step of applying a release agent to a portion where a non-coated portion of the current collector surface is to be provided to form a release agent layer;
After forming the release agent layer, a step of applying an adhesive to the surface of the current collector on which the release agent layer is formed to form an adhesive layer;
After forming the adhesive layer and release agent layer, the active material layer coating composition containing at least the active material and the binder is applied to the surface of the current collector on which these layers are formed. Forming a material layer;
For forming a non-aqueous electrolyte secondary battery, comprising the step of peeling the adhesive layer and the active material layer of the part where the non-coated portion is to be provided together with the release agent layer after forming the active material layer Manufacturing method of electrode plate. A method for producing an electrode plate for a non-aqueous electrolyte secondary battery, comprising an active material layer containing at least an active material and a binder on a current collector and a non-coated portion having no active material layer. There,
Applying an adhesive to the entire current collector surface to form an adhesive layer;
Forming a release agent layer by applying a release agent to a portion where an uncoated portion of the current collector surface on the side on which the adhesive layer is formed is provided;
After forming the adhesive layer and release agent layer, the active material layer coating composition containing at least the active material and the binder is applied to the surface of the current collector on which these layers are formed. Forming a material layer;
A step of separating the active material layer of the portion where the non-coated portion is to be provided after the formation of the active material layer together with the release agent layer at the boundary between the adhesive layer and the release agent layer, Manufacturing method of electrode plate for water electrolyte secondary battery.   In the step of separating the active material layer, the active material layer is peeled off at the portion where the non-coated portion is to be provided by adhering and peeling the peeling sheet on the surface of the portion where the non-coated portion is to be provided at the surface. The manufacturing method of the electrode plate for nonaqueous electrolyte secondary batteries of Claim 1 or 2 characterized by the above-mentioned.   In the active material layer peeling step, at least a portion of the active material layer where the non-coated portion is to be provided is impregnated with a heat-meltable material and solidified, and then the active material layer where the non-coated portion is to be provided is peeled The manufacturing method of the electrode plate for nonaqueous electrolyte secondary batteries of Claim 1 or 2 characterized by the above-mentioned.   A copper foil current collector is used as the current collector, and an adhesive containing a coupling agent, a carboxylic acid or a sulfonic acid as the adhesive is applied to the surface of the copper foil current collector. The manufacturing method of the electrode plate for nonaqueous electrolyte secondary batteries in any one of Claims 1 thru | or 4.   The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to claim 5, wherein a silane coupling agent having an amino group as a terminal group is used as the coupling agent.   The method for producing an electrode plate for a nonaqueous electrolyte secondary battery according to claim 5, wherein oxalic acid is used as the carboxylic acid.   The non-aqueous electrolyte secondary solution according to any one of claims 1 to 7, wherein a thermoplastic resin selected from polyvinylidene fluoride, polyethylene or a derivative thereof, polypropylene or a derivative thereof is used as the release agent. Manufacturing method of battery electrode plate.   The nonaqueous electrolytic solution according to any one of claims 1 to 7, wherein a thermoplastic resin having a melting point of 100 to 250 ° C and a melt viscosity of 100 to 50,000 cps is used as the release agent. A method for producing an electrode plate for a secondary battery.

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