JP3614990B2 - Sheet electrode manufacturing method and non-aqueous electrolyte battery - Google Patents

Description

【表２】

これらの表から、実施例１〜２４により、各塗布部では塗布直後から塗布終了まで塗布厚が均一で安定しており、かつ電極合剤塗布液の全く存在しない良好な未塗布部を有する塗布シートが得られることがわかった。そして、これらのシートから電極を作製し、これを用いて常法により非水電解質電池を製造したところ、電池性能が良好で安全性に優れた電池が得られた。
【００８３】
これに対して、比較例１〜１４で作製された塗布シートでは、未塗布部の状態は良好であったが、塗布部と未塗布部との境界における塗布液の切れが悪く、塗布部の端部において塗布層が盛り上がってしまったり、塗布厚が極端に薄くなってしまった。その結果、得られた塗布シートをローラープレス機により圧縮成形したところ、塗布層が盛り上がった塗布シートでは、導電性基材の切断が発生した。また、塗布厚が極端に薄い塗布シートを用いて製造した電池では、電池性能および安全性が極端に低く、実用に供し得なかった。
【００８４】
【発明の効果】
以上の説明から明らかなように、本発明によれば、電極合剤塗布液が存在しない良好な未塗布部を安定して効率的に形成し、特性の良好なシート状極板を製造することができる。そして、塗布液の塗布と同時に未塗布部が形成されるので、タブ板溶接のために電極合剤層を剥離する必要がなく、作業工数減による省人化や塗布工程の効率向上を図ることができる。
【図面の簡単な説明】
【図１】本発明に用いるダイノズルの一例を模式的に示す断面図。
【図２】本発明により導電性基材上に形成される電極合剤塗布液の塗布パターンを示す平面図。
【図３】本発明のシート状極板の製造方法に使用する塗布装置の一実施例を模式的に示す図。
【図４】同塗布装置におけるダイノズルの別の設置態様を示す図。
【図５】本発明に使用する塗布装置において、塗布液の間欠供給システムの別の例を示す図。
【図６】本発明の実施例で得られた塗布シートの塗布方向に沿った断面図。
【図７】円筒形の非水電解質電池の構成の一例を示す断面図。
【図８】従来からのタブ板の接続方法を示す図であり、（ａ）は表面図、（ｂ）は裏面図、（ｃ）は（ａ）におけるＡ−Ａ切断斜視図。
【符号の説明】
１２………ダイノズル
１３………リップ
１４………ランド
１５………マニホールド
１６………電極材料（合剤）塗布液
１７………導電性基材
１８………電極合剤塗布部
１９………未塗布部
２０………バックアップロール
２２………塗布液供給システム
２３………塗布液タンク
２４………定流量ポンプ
２６………吐出弁
２８………リターン弁
２９………流量計
３０………不活性ガス
３１………密閉タンク[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a sheet-like electrode plate, and a nonaqueous electrolyte battery using a sheet-like electrode produced from the sheet-like electrode plate.
[0002]
[Prior art]
Non-aqueous electrolyte batteries using lithium as the negative electrode active material are attracting attention as high energy density batteries. In particular, primary batteries using manganese dioxide, fluorocarbon, thionyl chloride, etc. as the positive electrode active material are used in calculators and watches. It is often used as a backup battery for power supplies and memory.
[0003]
In recent years, as various electronic devices such as camera-integrated VTRs, laptop computers, and mobile phones have become smaller and lighter, the demand for high-energy density secondary batteries has increased, and the use of carbon materials as a negative electrode has increased. Research on lithium secondary batteries as materials has been actively conducted.
[0004]
However, in a battery using a non-aqueous electrolyte mainly composed of an organic electrolyte, represented by a lithium battery (non-aqueous electrolyte battery), the electric conductivity of the non-aqueous electrolyte is lower than that of an aqueous electrolyte. It needs to be thin. In addition, since it is necessary to increase the reaction area in order to extract a large current, a spiral structure is adopted in which positive and negative electrode plates are formed into a sheet shape and these electrode plates are wound into a roll shape via a separator. ing.
[0005]
An example of the structure of such a battery is shown in FIG.
[0006]
In the battery shown in the figure, a positive electrode plate 1 and a negative electrode plate 2 are stacked via an insulating thin film separator 3 having a large ion permeability, wound in a roll shape, and accommodated in a container 4. And the positive electrode tab board 5 is connected to the electrical power collector of the inner peripheral edge part of the positive electrode plate 1, and the positive electrode tab board 5 is further connected to the positive electrode terminal 6 via the sealing body 6a. A negative electrode tab plate 7 is connected to the current collector at the outer peripheral end of the negative electrode plate 2, and the negative electrode tab plate 7 is further connected to a negative electrode terminal 8 at the bottom of the container 4.
[0007]
Here, each of the positive electrode plate 1 and the negative electrode plate 2 is a sheet-like electrode plate in which an electrode mixture mainly composed of a positive electrode active material, a negative electrode active material, a conductive agent, a binder, or the like is applied to both surfaces of a conductive substrate. From FIG. 8A to FIG. 8C, when the positive electrode tab plate 5 and the negative electrode tab plate 6 are connected to the positive electrode plate 1 and the negative electrode plate 2, respectively, As shown in the figure, a method has been adopted in which a tab plate 10 (positive electrode tab plate or negative electrode tab plate) is cut together with the electrode plate 9 (positive electrode plate or negative electrode plate), and the tab plate 10 is folded back and crimped. . However, the battery in which the tab plate 10 is connected by this method has an unstable impedance and is unstable. In addition, there are problems such that the caulked portion becomes thicker or the end of the caulked portion 11 breaks through the separator and short-circuits.
[0008]
In addition, a method such as welding is also used to connect the tab plate to the electrode plate. However, in order to perform the welding, the welded portion of the electrode plate is used as a material portion of a conductive base material without an electrode mixture. There is a need.
[0009]
And in order to form the fabric part of such an electroconductive base material, conventionally, removing the electrode mixture layer formed by application | coating of an electrode material coating liquid and drying was performed. Japanese Patent Publication No. 60-48865 discloses a method of removing a line with a pair of knife materials and scraping off an electrode mixture layer between the lines with a slot mill. Japanese Patent Application Laid-Open No. 2-98040 proposes a method in which the electrode mixture is brought into contact with both sides of the electrode mixture layer applied on both surfaces to peel and remove the electrode mixture. However, these methods require an extra work step of peeling and removing the electrode mixture, and the removed electrode mixture is wasted.
[0010]
On the other hand, a method of leaving the cloth portion of the conductive base material in the electrode mixture application step is also performed. That is, in the production of the sheet-like electrode plate, the electrode material (electrode mixture) coating liquid obtained by mixing a conductive agent with an electrode active material and further adding a binder or the like into a paste is excessively applied in advance to both surfaces of the conductive substrate. A method has been proposed in which uncoated portions are provided at regular intervals in the running direction (longitudinal direction) of the conductive base material by supplying and stopping the supply of the coating liquid using a shutter provided immediately before the doctor blade. However, in this method, even after the shutter is closed and the supply of the coating solution is stopped, the coating solution remaining on the doctor blade often adheres to the uncoated portion. Therefore, when the tab plate is connected to the uncoated portion by welding, there is a problem that the adhering electrode mixture decreases the welding strength of the tab plate, and the tab plate is easily peeled off.
[0011]
Moreover, in roller application, such as a gravure method or a reverse method, a method of providing an uncoated portion of the electrode mixture in the running direction of the conductive substrate is conceivable. For example, an uncoated portion can be formed by separating the backup roll from the coating roll by a reverse roll method in which the coating liquid is transferred to the conductive substrate by the backup roll. However, since the coating roll moves while the backup roll is away from the coating roll, the coating thickness when the backup roll comes into contact with the coating solution on the coating roll next becomes extremely thick. In order to avoid this, it is conceivable that the operation of the coating roll is stopped at the same time as the backup roll is separated. However, this method is not improved greatly, although it is somewhat improved. In addition, when the coating roll is stopped, the coating solution on the roll is unevenly dried, and swells occur at the beginning and end of coating, resulting in uneven coating layer thickness and poor surface smoothness. .
[0012]
Further, an electrode material coating solution is discharged by an extrusion type liquid injector having a slot nozzle, and applied while providing an uncoated portion in parallel with the traveling direction (longitudinal direction) on the traveling conductive substrate. A method for manufacturing a plate has been proposed (described in JP-A-7-94170). This method is a continuous coating method, and a good coating layer can be formed while continuously providing non-coated portions in the form of vertical stripes in which no electrode mixture is present.
[0013]
However, in this method, when changing the position or width of the uncoated portion, the slot nozzle is replaced, or a plate-like body that is closely fixed to the slot portion is moved in order to fractionate the opening portion. A process was required.
[0014]
[Problems to be solved by the invention]
As described above, in order to weld the tab plate, the electrode mixture layer once applied and dried is peeled and removed, and the method of taking out the dough portion of the conductive base material requires an extra step. Could not be produced efficiently.
[0015]
Also, in the method of forming the uncoated part of the electrode mixture with the shutter provided just before the doctor blade, the electrode mixture adhering to the uncoated part causes a decrease in the welding strength of the tab plate and the tab plate peeling after welding. There was a problem that it was easy to make. Furthermore, in the method of providing an uncoated portion by roller coating, the beginning and end of the coated portion are raised, and the conductive base material may be cut during pressing.
[0016]
Further, in the method of applying the electrode material coating liquid while using the extrusion type liquid injector having the slot nozzle and providing the non-coated part along the running direction on the conductive substrate, the position of the uncoated part In addition, an extra process is required when changing the width and width, and this is not always an efficient method.
[0017]
The present invention has been made to solve these problems, and in the manufacture of a sheet-like electrode plate used as an electrode of a nonaqueous electrolyte battery, an uncoated portion for welding a tab plate on a conductive substrate is provided. It aims at providing the method of providing the favorable electrode mixture layer of arbitrary length, forming efficiently.
[0018]
[Means for Solving the Problems]
The above problem is that in the production of a non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte, the apparent viscosity is 500 to 100,000 mPa · S (shear rate 13 sec. ^-1 The electrode material coating liquid having a viscosity of) is discharged by a die nozzle connected to the coating liquid supply system, and the coating liquid is applied to the traveling conductive substrate while providing uncoated portions at regular intervals in the longitudinal direction. Coating After that, the electrode material coated sheet obtained by drying and press molding is cut out in parallel to the longitudinal direction according to a predetermined battery height, and then cut in the width direction to take out one sheet-like electrode plate. This is achieved by a method for producing a sheet-like electrode plate characterized by
[0019]
Moreover, in order to provide an uncoated part in such a manufacturing method, any of the methods shown below can be taken. That is, a first method for moving the die nozzle in a direction that is substantially perpendicular to the coating surface of the conductive substrate, the conductive substrate being substantially perpendicular to the tip surface of the die nozzle In A second method of moving in a separating direction, a third method of swinging the die nozzle in a direction parallel to the traveling direction of the conductive substrate, and intermittently supplying the coating liquid to the die nozzle in the coating liquid supply system Of the fourth methods to be performed, any one of the methods can be employed. Furthermore, by performing the fourth method (intermittent supply of the coating liquid to the die nozzle) in combination with the first to third methods described above, it is possible to more efficiently and reliably form the uncoated portion. Is possible.
[0020]
An example of a die nozzle used in the present invention is shown in FIG.
[0021]
As shown in the figure, the die nozzle 12 has two lips 13 facing each other with a suitable gap to form a land 14, and has a liquid reservoir manifold 15 communicating with the land 14. . An electrode material (electrode mixture) coating solution 16 is quantitatively supplied to the manifold 15 by a coating solution supply system (not shown) provided outside, and further, an opening is formed at the tip of the lip 13 via the land 14. It is discharged from the land outlet. The die nozzle 12 is installed so as to keep a certain distance from the conductive base material 17 on which the tip of the lip 13 travels, and the electrode material coating liquid 16 discharged from the tip of the lip 13 is placed on the conductive base material 17. Uniformly applied. As a material constituting the die nozzle 12, a material having good corrosion resistance is selected when the coating solution is corrosive. Usually, a metal, an alloy, a ceramic, a plastic, or the like is used. Further, a preferable gap between the two lips 13, that is, a preferable width of the land 14 outlet portion is 50 to 1200 μm, more preferably 100 to 800 μm, although it varies depending on the viscosity (apparent viscosity) of the electrode material coating solution. .
[0022]
In the present invention, in the application of the electrode material coating liquid 16 by the die nozzle 12, the die nozzle 12 or the conductive substrate 17 is placed on the coating surface of the conductive substrate 17 or the tip surface of the lip 13 of the die nozzle 12. Or move the die nozzle 12 in a direction parallel to the running direction of the conductive substrate 17 (swing), or by a coating liquid supply system By intermittently supplying the coating liquid to the die nozzle 12, as shown in the coating pattern in FIG. 2, in the electrode mixture coating unit 18 of the conductive substrate 17, at regular intervals in the longitudinal direction (coating direction). An uncoated portion 19 can be provided. The uncoated portion 19 may be formed at either the same position on the front and back surfaces of the conductive base material 17 or at a slightly shifted position. Further, uncoated ears 19a are also formed at both ends in the width direction of the conductive base material 17, but these are provided so that the coating solution does not protrude from both width ends and adhere to a backup roll or the like. Unpainted part, usually cut off and not used for electrode plates
[0023]
In such an application pattern, the length of the application part 18 and the length of the non-application part 19 can be arbitrarily changed in accordance with the size of the electrode to be cut out and used. Further, a coating sheet having such a coating pattern is first cut out parallel to the longitudinal direction in accordance with the size (height) of the battery (the cut line is indicated by a broken line a), and then cut in the width direction. At this time, as shown by the broken line B, the uncoated part 19 can be divided into two parts, or as shown by the broken line C, it is separated at the boundary between the coated part 18 and the uncoated part 19. You can also. Furthermore, the thickness of the coating film having such a coating pattern is preferably in the range of 5 to 1800 μm (particularly 50 to 500 μm) after drying.
[0024]
The electrode material coating solution applied in the present invention may contain an electrode active material, a conductive agent, a binder, a solvent, and the like. As an electrode active material, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ Can be any compound as long as it is a compound that can be inserted and / or released, and transition metal oxides, transition metal chalcogenides, carbonaceous materials, etc. can be used, particularly lithium-containing transition metal oxides or carbons. The use of quality materials is preferred. The transition metal is preferably composed mainly of Co, Mn, Ni, V, and Fe. Specifically, as such a transition metal oxide, specifically, LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ LiCoVO ₄ , LiNiVO ₄ LiCo _0.9 Sn _0.1 O ₂ , Fe ₃ O ₄ , V ₂ O ₅ Etc. Further, as the carbon material, the 002 plane spacing is 0.335 to 0.38 nm, and the density is 1.1 to 2.3 g / cm. ³ In particular, graphite, petroleum coke, cresol resin calcined carbon, furan resin calcined carbon, polyacrylonitrile fiber calcined carbon, vapor-grown carbon, mesophase pitch calcined carbon and the like can be mentioned.
[0025]
Any conductive agent can be used as long as it is an electron conductive material that does not cause a chemical change in the constructed battery. Usually, conductive materials such as natural graphite (such as scaly graphite and scaly graphite), artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder, metal fiber, or polyphenylene derivative are used alone or in combination. Two or more types can be mixed and used, and the combined use of graphite and acetylene black is particularly preferable.
[0026]
As the binder, a polysaccharide, a thermoplastic resin, or a polymer having rubber elasticity that is difficult to dissolve or swell in the organic electrolyte used in the non-aqueous electrolyte battery can be used alone or in combination. . Specifically, starch, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, fluororubber, ethylene-propylene-dienter polymer (EPDM), styrene butadiene rubber, polybutadiene, poly Examples thereof include ethylene oxide. These binders may be dissolved in a solvent, or may be in an emulsion state such as dispersion or suspension.
[0027]
Furthermore, as a solvent for kneading these electrode active materials, conductive agents, and binders, water or a mixture of one or more organic solvents can be used. The type of organic solvent is not particularly limited, but use of N-methylpyrrolidone, xylene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethanol, methanol, ethyl acetate, butyl acetate, methylene chloride, ethylene chloride, ethyl cellosolve, etc. Is preferred.
[0028]
In the present invention, the composition of the electrode material coating solution is not particularly limited. Usually, the ratio of the conductive agent is 1 to 10 parts by weight and the binder is 0.1 to 20 parts by weight with respect to 100 parts by weight of the electrode active material. It is preferable to add a solvent so that the solid content ratio is 10 to 80% by weight. Moreover, such an electrode material coating solution has a shear rate of 13 sec. ^-1 The apparent viscosity at 500 to 100,000 mPa · S is more preferably 1000 to 50000 mPa · S. If the apparent viscosity of the coating liquid is less than 500 Pa · S, dripping is likely to occur from the tip of the die nozzle lip after the supply of the coating liquid is stopped, and conversely if the apparent viscosity exceeds 100,000 mPa · S, the discharge pressure of the die nozzle is Since it becomes too high, the caliber (lip clearance) of the land tends to become unstable, and uniform coating thickness accuracy cannot be obtained. Furthermore, the temperature of the coating solution can be controlled as necessary, but it is preferable to set the temperature within the range of 10 to 60 ° C. (especially 15 to 45 ° C.) and the temperature of the coating solution and the die nozzle at the time of coating. It is desirable to always apply them equally.
[0029]
The conductive substrate used in the present invention is not particularly limited, but a metal foil such as aluminum, copper, nickel, and stainless steel, a conductive film such as an inorganic oxide, an organic polymer material, and carbon. Can be used. Moreover, although the form of such an electroconductive base material can be made into various forms, such as a continuous sheet, a perforated sheet, and a net-like (net-like) sheet, it is particularly preferable to use a continuous sheet. Furthermore, the thickness of the conductive substrate is preferably 5 to 30 μm.
[0030]
In the present invention, the electrode material coating solution is applied to both the front and back surfaces of such a conductive substrate sequentially or simultaneously, and then conveyed to a drying chamber to remove the solvent in the coating film, and then between the press rollers. It is pressed by a method such as passing through. As a drying method, hot air drying, infrared drying, a drying method such as a contact drum, or a combination thereof can be used. The drying temperature in the case of hot air drying is set according to the composition of the coating solution, but is preferably 50 to 180 ° C (particularly 90 to 130 ° C).
[0031]
A primary battery or a secondary battery such as a cylinder or a prism can be manufactured by using the electrode manufactured from the sheet-like electrode plate manufactured by the method of the present invention as one or both of the positive electrode and the negative electrode. Here, as a separator which isolate | separates a positive electrode sheet and a negative electrode sheet, a polyethylene film, a microporous polypropylene film, a glass fiber film etc. are mentioned, for example. Further, as the electrolyte, as an organic solvent, for example, at least one aprotic organic solvent such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, etc. A solvent obtained by mixing the above and a lithium salt soluble in the solvent, for example, LiClO ₄ , LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ And a solution composed of one or more kinds of salts.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0033]
FIG. 3 is a view schematically showing a coating apparatus used in the method for producing a sheet-like electrode plate of the present invention.
[0034]
In this coating apparatus, the conductive base material 17 travels continuously in close contact with the roll surface of the rotating backup roll 20, and the tip of the lip 13 is kept at a constant interval with respect to the conductive base material 17. A die nozzle 12 is installed. The die nozzle 12 is preferably arranged so that the lip 13 is exactly perpendicular to the application surface of the conductive substrate 17, but may be arranged to form an angle other than the right angle. Note that the backup roll 20 functions to maintain the distance between the conductive base material 17 and the die nozzle 12 (tip portion of the lip 13) and to keep the traveling speed of the conductive base material 17 constant. Further, as shown in FIG. 4, the conductive base material 17 is caused to run in close contact with the roll surfaces of the backup roll 20 and the guide roll 21 that are arranged adjacent to each other, and is electrically connected to the tip of the lip 13 at the intermediate part of these rolls. The die nozzle 12 can also be installed so as to keep a certain distance from the conductive substrate 17.
[0035]
The die nozzle 12 has two lips 13 (an inlet lip 13a and an outlet lip 13b) facing each other so as to maintain an appropriate gap, and a land 14 is formed by these lips 13. In addition, a manifold 15 for storing a liquid communicating with the land 14 is provided inside. The manifold 15 has a function of buffering fluctuations in the supply amount of the coating liquid. The electrode material coating solution 16 is quantitatively supplied to the manifold 15 by a coating solution supply system 22 provided outside the die nozzle 12, and is further discharged from the tip of the lip 13 through the land 14.
[0036]
The coating liquid supply system 22 is a constant coating liquid tank 23 in which the adjusted electrode material coating liquid 16 is stored, and the coating liquid 16 stored in the tank 23 is continuously supplied into the manifold 15 of the die nozzle 12. A flow rate pump 24, a supply flow path (supply path) 25 connecting the coating liquid tank 23 and the die nozzle 12, a discharge valve 26 inserted in the supply flow path 25, and an intermediate portion (discharge valve) of the supply flow path 25 26, a return flow path 27 branched and connected to the upstream side 26, and a return valve 28 interposed in the return flow path 27. In the figure, reference numeral 29 indicates a flow meter.
[0037]
When coating is performed by the die nozzle 12 connected to such a coating liquid supply system 22, the adjusted electrode material coating liquid 16 is passed from the coating liquid tank 23 tank through the supply flow path 25 by the constant flow pump 24 to the die nozzle. Twelve manifolds 15 are continuously supplied. Then, the coating liquid 16 supplied to the manifold 15 is discharged from the outlet portion at the tip of the lip 13 through the land 14 and applied onto the conductive base material 17 that runs continuously.
[0038]
In such application, as a method of providing an uncoated part on the conductive substrate 17 at regular intervals in the longitudinal direction, the following four types of flows can be mentioned.
[0039]
1) The die nozzle 12, that is, the tip of the lip 13 is moved in a direction away from the conductive base material 17, thereby forming an uncoated portion. At this time, the die nozzle 12 may move in a direction perpendicular to the application surface of the conductive base material 17 or may move in a direction that is substantially perpendicular but forms other angles. Further, the movement should be linear, but it may be curved.
[0040]
2) The die nozzle 12 is swung or rotated around a suitable point in a direction parallel to the traveling direction of the conductive substrate 17 (traveling direction or the opposite direction), and the tip of the lip 13 is moved upward or An uncoated portion is formed by retreating downward. At this time, the center of rotation may be the center of gravity of the die nozzle 12 or other points.
[0041]
3) The conductive base material 17 is moved in a direction substantially perpendicular to the tip surface of the lip 13 of the die nozzle 12 and is separated from the tip portion of the lip 13 to form an uncoated portion.
[0042]
4) Neither the die nozzle 12 nor the conductive base material 17 is moved, and the coating liquid supply system 22 intermittently supplies the electrode material coating liquid 16 to the die nozzle 12 so that the coating liquid is applied to the die nozzle 12 at regular intervals. By completely stopping the supply, an uncoated portion is formed.
[0043]
That is, in the coating liquid supply system 22, the supply of the coating liquid to the die nozzle 12 is stopped by closing the discharge valve 26, and when such supply is stopped, the return valve 28 is opened and the coating liquid 16 is returned to the return flow path. 27, and returns to the coating liquid tank 23. When supply of the coating liquid is started, the discharge valve 26 is opened simultaneously with the return valve 28 being closed, and the coating liquid 16 is supplied into the manifold 15 of the die nozzle 12 through the discharge valve 26 by opening and closing the valve.
[0044]
Further, the supply of the coating liquid to the die nozzle 12 can be stopped only by closing the discharge valve 26 and stopping the operation of the constant flow pump 24 without using the return flow path 27. Further, as shown in FIG. 5, the coating liquid 16 is supplied by feeding an inert gas 30 such as nitrogen or argon into the sealed tank 31 containing the coating liquid at a constant pressure. In such a coating liquid supply system, the supply of the coating liquid to the die nozzle 12 can be stopped only by opening / closing the discharge valve 26, and an uncoated portion can be formed.
[0045]
In any of the flows 1) to 4), it is preferable that the tip of the lip 13 of the die nozzle 12 is arranged in a direction substantially perpendicular to the application surface of the conductive substrate 17 during application. You may arrange | position so that an angle other than a right angle may be made. Further, the intermittent supply method of the coating liquid to the die nozzle 18 shown in 4) is more preferably performed in combination with the methods 1) to 3).
[0046]
【Example】
Next, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples unless departing from the gist of the present invention.
[0047]
Example 1
LiCoO as positive electrode active material ₂ 55.2 parts by weight, 3.6 parts by weight of acetylene black as a conductive agent, and 1.2 parts by weight of a fluororubber binder as a binder, and 40 parts by weight of ethyl acetate as a solvent. By kneading and dispersing, a positive electrode mixture coating solution having a solid content concentration of 60% by weight was obtained. The apparent viscosity of this coating solution is 3000 mPa · S (shear rate 13 sec. ^-1 )Met.
[0048]
While providing this slurry-like coating solution on both sides of an aluminum foil having a thickness of 15 μm using the coating apparatus shown in FIG. 3 and providing uncoated portions at regular intervals in the longitudinal direction by the method 1) described above, After coating one side at a time, it was dried with hot air at 120 ° C. The distance between the tip of the lip during application and the aluminum foil as the conductive substrate is 0.4 mm, and the distance between the die nozzles when not applied is 5 mm in the direction perpendicular to the aluminum foil. Yes, the coating speed, that is, the traveling speed of the aluminum foil was 2 m / min. Moreover, the coating liquid supply to the die nozzle was performed using an intermittent supply system.
[0049]
Example 2
As a positive electrode mixture coating solution, LiCoO was used in the same manner as in Example 1. ₂ , Acetylene black, fluororubber binder, and ethyl acetate, solid content concentration of 65% by weight, apparent viscosity of 25000 mPa · S (shear rate 13 sec ^-1 The coating solution was applied to both surfaces of the aluminum foil one side at a time in the same manner as in Example 1 while providing uncoated portions at regular intervals in the longitudinal direction.
[0050]
Example 3
As a positive electrode mixture coating solution, LiCoO was used in the same manner as in Example 1. ₂ , Acetylene black, fluororubber binder, and ethyl acetate, solid content concentration of 70% by weight, apparent viscosity of 40000 mPa · S (shear rate 13 sec. ^-1 The coating solution was applied to both surfaces of the aluminum foil one side at a time in the same manner as in Example 1 while providing uncoated portions at regular intervals in the longitudinal direction.
[0051]
Example 4
Add 58.2 parts by weight of carbon fiber as the negative electrode active material, 1.2 parts by weight of the copolymer of styrene and butadiene as the binder, and 0.6 parts by weight of carboxymethyl cellulose as the thickener. The mixture was kneaded and dispersed using 40 parts by weight of pure water as a solvent to obtain a negative electrode mixture coating solution having a solid content concentration of 60% by weight. The apparent viscosity of this coating solution is 3000 mPa · S (shear rate 13 sec. ^-1 )Met.
[0052]
While applying this slurry-like coating solution to both sides of a 12 μm thick copper foil, using the coating apparatus shown in FIG. 3 and providing uncoated portions at regular intervals in the longitudinal direction by the method described in 1) above, one side at a time After coating, it was dried with hot air at 100 ° C. The distance between the tip of the lip during coating and the copper foil as the conductive substrate is 0.3 mm, the retreat distance of the die nozzle when not coated is 5 mm in the direction perpendicular to the copper foil, and the coating speed is 2 m. / Min. Moreover, the coating liquid supply to the die nozzle was performed using an intermittent supply system.
[0053]
Example 5
As a negative electrode mixture coating solution, fiber-based carbon, a styrene-butadiene copolymer compound, carboxymethylcellulose, and pure water were kneaded in the same manner as in Example 4 to obtain a solid content concentration of 64% by weight and an apparent viscosity of 10,000 mPa · S. (Shear rate 13 sec ^-1 The coating solution was applied on both sides of the copper foil one side at a time in the same manner as in Example 4 while providing uncoated portions at regular intervals in the longitudinal direction.
[0054]
Example 6
As a negative electrode mixture coating solution, fiber-based carbon, a styrene-butadiene copolymer compound, carboxymethylcellulose, and pure water were kneaded in the same manner as in Example 4 to obtain a solid content concentration of 68% by weight and an apparent viscosity of 20000 mPa · S. (Shear rate 13 sec ^-1 The coating solution was applied on both sides of the copper foil one side at a time in the same manner as in Example 4 while providing uncoated portions at regular intervals in the longitudinal direction.
[0055]
Example 7
As the positive electrode mixture coating liquid, the same coating liquid as in Example 1 (solid content concentration 60 wt%, apparent viscosity 3000 mPa · S) was used, and this was applied to both sides of the aluminum foil using the coating apparatus shown in FIG. ), While applying unapplied portions at regular intervals in the longitudinal direction, the coating was performed one side at a time. The distance between the tip of the lip during coating and the aluminum foil as the conductive substrate is 0.4 mm, and the retreat angle of the die nozzle when not coated is 3 ° on the side opposite to the traveling direction of the aluminum foil. Was applied at 2 m / min. Further, the coating liquid was supplied to the die nozzle by using an intermittent supply system together.
[0056]
Example 8
As the positive electrode mixture coating liquid, the same coating liquid as in Example 2 (solid content concentration 65% by weight, apparent viscosity 25000 mPa · S) was used, and this was applied to both sides of the aluminum foil in the longitudinal direction in the same manner as in Example 7. Application was performed while providing an unapplied portion at regular intervals.
Example 9
As the positive electrode mixture coating liquid, the same coating liquid as in Example 3 (solid content concentration 70 wt%, apparent viscosity 40000 mPa · S) was used, and this was applied to both sides of the aluminum foil in the longitudinal direction in the same manner as in Example 7. One side was applied while providing an unapplied part at regular intervals.
[0057]
Example 10
As the negative electrode mixture coating liquid, the same coating liquid as in Example 4 (solid content concentration 60% by weight, apparent viscosity 3000 mPa · S) was used, and this was applied to both sides of the copper foil using the coating apparatus shown in FIG. ), While applying unapplied portions at regular intervals in the longitudinal direction, the coating was performed one side at a time. The distance between the tip of the lip during coating and the copper foil as the conductive substrate is 0.3 mm, and the retreat angle of the die nozzle when not coated is 3 ° on the side opposite to the traveling direction of the copper foil. Was applied at 2 m / min. Further, the coating liquid was supplied to the die nozzle by using an intermittent supply system together.
[0058]
Example 11
As the negative electrode mixture coating liquid, the same coating liquid as in Example 5 (solid content concentration 64 wt%, apparent viscosity 10000 mPa · S) was used, and this was applied to both sides of the copper foil in the longitudinal direction in the same manner as in Example 10. One side was applied while providing an unapplied part at regular intervals.
[0059]
Example 12
As the negative electrode mixture coating liquid, the same coating liquid as in Example 6 (solid content concentration 68 wt%, apparent viscosity 20000 mPa · S) was used, and this was applied to both sides of the copper foil in the longitudinal direction in the same manner as in Example 10. One side was applied while providing an unapplied part at regular intervals.
[0060]
Example 13
As the positive electrode mixture coating liquid, the same coating liquid as in Example 1 (solid content concentration 60 wt%, apparent viscosity 3000 mPa · S) was used, and this was applied to both sides of the aluminum foil using the coating apparatus shown in FIG. ) By one side while providing an unapplied portion at regular intervals in the longitudinal direction. The distance between the tip of the lip when applied and the aluminum foil as the conductive substrate is 0.4 mm, and the receding distance of the aluminum foil when not applied is 5 mm in the direction perpendicular to the lip tip of the die nozzle. The coating speed was 2 m / min. Further, the coating liquid was supplied to the die nozzle by using an intermittent supply system together. Example 14
As the positive electrode mixture coating solution, the same coating solution as in Example 2 (solid content concentration 65 wt%, apparent viscosity 25000 mPa · S) was used, and this was applied to both sides of the aluminum foil in the longitudinal direction in the same manner as in Example 13. One side was applied while providing an unapplied part at regular intervals.
Example 15
As the positive electrode mixture coating liquid, the same coating liquid as in Example 3 (solid content concentration 70 wt%, apparent viscosity 40000 mPa · S) was used, and this was applied to both sides of the aluminum foil in the longitudinal direction in the same manner as in Example 13. One side was applied while providing an unapplied part at regular intervals.
Example 16
As the negative electrode mixture coating liquid, the same coating liquid as in Example 4 (solid content concentration 60 wt%, apparent viscosity 3000 mPa · S) was used, and this was applied to both sides of the copper foil using the coating apparatus shown in FIG. ) By one side while providing an unapplied portion at regular intervals in the longitudinal direction. The distance between the lip tip when coated and the copper foil as the conductive substrate is 0.3 mm, and the receding distance of the copper foil when not coated is 5 mm perpendicular to the lip tip surface of the die nozzle. The coating speed was 2 m / min. Further, the coating liquid was supplied to the die nozzle by using an intermittent supply system together.
[0061]
Example 17
As the negative electrode mixture coating solution, the same coating solution as in Example 5 (solid content concentration 64 wt%, apparent viscosity 10000 mPa · S) was used, and this was applied to both sides of the copper foil in the longitudinal direction in the same manner as in Example 16. One side was applied while providing an unapplied part at regular intervals.
[0062]
Example 18
As the negative electrode mixture coating liquid, the same coating liquid as in Example 6 (solid content concentration 68 wt%, apparent viscosity 20000 mPa · S) was used, and this was applied to both sides of the copper foil in the longitudinal direction in the same manner as in Example 16. One side was applied while providing an unapplied part at regular intervals.
[0063]
Example 19
As the positive electrode mixture coating liquid, the same coating liquid as in Example 1 (solid content concentration 60% by weight, apparent viscosity 3000 mPa · S) was used. In the method of intermittently supplying the coating liquid to the die nozzle shown in 4), coating was performed one side at a time while providing an uncoated portion at regular intervals in the longitudinal direction. In addition, the space | interval of the lip front-end | tip part at the time of application | coating and the non-application | coating and the aluminum foil which is an electroconductive base material is 0.4 mm, and it apply | coated with the application | coating speed of 2 m / min.
[0064]
Example 20
As the positive electrode mixture coating solution, the same coating solution as in Example 2 (solid content concentration 65 wt%, apparent viscosity 25000 mPa · S) was used, and this was applied to both sides of the aluminum foil in the longitudinal direction in the same manner as in Example 19. One side was applied while providing an unapplied part at regular intervals.
Example 21
As the positive electrode mixture coating liquid, the same coating liquid as in Example 3 (solid content concentration 70 wt%, apparent viscosity 40000 mPa · S) was used, and this was applied to both sides of the aluminum foil in the longitudinal direction in the same manner as in Example 19. One side was applied while providing an unapplied part at regular intervals.
Example 22
As the negative electrode mixture coating liquid, the same coating liquid as in Example 4 (solid content concentration 60 wt%, apparent viscosity 3000 mPa · S) was used, and this was applied to both surfaces of the copper foil using the coating apparatus shown in FIG. In the method of intermittently supplying the coating liquid to the die nozzle shown in 4), coating was performed one side at a time while providing an uncoated portion at regular intervals in the longitudinal direction. In addition, the space | interval of the lip front-end | tip part at the time of application | coating and the non-application | coating and the copper foil which is an electroconductive base material is all 0.3 mm, and it apply | coated with the application | coating speed | rate of 2 m / min.
[0065]
Example 23
As the negative electrode mixture coating liquid, the same coating liquid as in Example 5 (solid content concentration 64% by weight, apparent viscosity 10000 mPa · S) was used, and this was applied to both sides of the copper foil in the longitudinal direction in the same manner as in Example 22. One side was applied while providing an unapplied part at regular intervals.
[0066]
Example 24
As the negative electrode mixture coating liquid, the same coating liquid as in Example 6 (solid content concentration 68% by weight, apparent viscosity 20000 mPa · S) was used. One side was applied while providing an unapplied part at regular intervals.
[0067]
Comparative Example 1
As a positive electrode mixture coating solution, LiCoO was used in the same manner as in Example 1. ₂ , Acetylene black, fluororubber binder, and ethyl acetate, solid content concentration is 50% by weight, apparent viscosity is 450 mPa · S (shear rate 13 sec. ^-1 The coating solution is prepared on both surfaces of the aluminum foil using the coating device shown in FIG. 3 and at the intervals in the longitudinal direction by the method of 2) as in Example 7. Were applied one side at a time.
[0068]
Comparative Example 2
As the positive electrode mixture coating solution, LiCoO was used in the same manner as in Example 1. ₂ , Acetylene black, fluororubber binder, and ethyl acetate, solid content concentration is 75% by weight, apparent viscosity is 120,000 mPa · S (shear rate 13 sec ^-1 The coating solution is prepared on both surfaces of the aluminum foil using the coating device shown in FIG. 3 and at the intervals in the longitudinal direction by the method of 2) as in Example 7. Were applied one side at a time.
[0069]
Comparative Example 3
As a negative electrode mixture coating solution, fiber-based carbon, a styrene-butadiene copolymer compound, carboxymethylcellulose, and pure water were kneaded in the same manner as in Example 4 to obtain a solid content concentration of 45% by weight and an apparent viscosity of 420 mPa · S. (Shear rate 13 sec ^-1 The coating solution is prepared on both sides of the copper foil, using the coating apparatus shown in FIG. Were applied one side at a time.
[0070]
Comparative Example 4
As a negative electrode mixture coating solution, fiber-based carbon, a styrene-butadiene copolymer compound, carboxymethyl cellulose, and pure water were kneaded in the same manner as in Example 4 to obtain a solid content concentration of 70% by weight and an apparent viscosity of 110000 mPa · S. (Shear rate 13 sec ^-1 The coating solution is prepared on both sides of the copper foil, using the coating apparatus shown in FIG. Were applied one side at a time.
[0071]
Comparative Example 5
As the positive electrode mixture coating liquid, the same coating liquid as in Example 1 (solid content concentration 60% by weight, apparent viscosity 3000 mPa · S) is used, and this is separated on both sides of the aluminum foil by the reverse roll method and the backup roll is separated. At the same time, the coating roll was stopped, and one side was coated while providing uncoated portions at regular intervals in the longitudinal direction. The coating was performed at a coating speed of 2 m / min.
[0072]
Comparative Example 6
The same positive electrode mixture coating solution as in Example 2 (solid content concentration 65% by weight, apparent viscosity 25000 mPa · s) was used on both sides of the aluminum foil at regular intervals in the longitudinal direction in the same manner as in Comparative Example 5. Each side was coated while providing an uncoated portion.
[0073]
Comparative Example 7
The same positive electrode mixture coating solution as in Example 3 (solid content concentration 70% by weight, apparent viscosity 40000 mPa · S) was used on both sides of the aluminum foil at regular intervals in the longitudinal direction in the same manner as in Comparative Example 5. Each side was coated while providing an uncoated portion.
[0074]
Comparative Example 8
As the positive electrode mixture coating liquid, the same coating liquid as in Comparative Example 1 (solid content concentration 50 wt%, apparent viscosity 450 mPa · S) was used, and this was applied to both sides of the aluminum foil in the longitudinal direction in the same manner as in Comparative Example 5. The coating was performed one side at a time while providing an uncoated portion at regular intervals.
[0075]
Comparative Example 9
As the positive electrode mixture coating liquid, the same coating liquid as in Comparative Example 2 (solid concentration 75% by weight, apparent viscosity 120,000 mPa · S) was used, and this was applied to both sides of the aluminum foil in the longitudinal direction in the same manner as in Comparative Example 5. The coating was performed one side at a time while providing an uncoated portion at regular intervals.
[0076]
Comparative Example 10
As the negative electrode mixture coating liquid, the same coating liquid as in Example 4 (solid content concentration 60 wt%, apparent viscosity 3000 mPa · S) was used, and this was applied to both sides of the copper foil in the longitudinal direction in the same manner as in Comparative Example 5. The coating was performed one side at a time while providing an uncoated portion at regular intervals.
[0077]
Comparative Example 11
The same negative electrode mixture coating liquid (solid content concentration 64% by weight, apparent viscosity 10000 mPa · s) as in Example 5 was used, and this was applied to both sides of the copper foil at regular intervals in the longitudinal direction in the same manner as in Comparative Example 5. Each side was coated while providing an uncoated portion.
[0078]
Comparative Example 12
The same negative electrode mixture coating liquid as in Example 6 (solid content concentration 68 wt%, apparent viscosity 20000 mPa · s) was used, and this was applied to both sides of the copper foil at regular intervals in the longitudinal direction in the same manner as in Comparative Example 5. Each side was coated while providing an uncoated portion.
[0079]
Comparative Example 13
The same coating liquid as in Comparative Example 3 (solid content concentration 45 wt%, apparent viscosity 420 mPa · S) was used as the negative electrode mixture coating liquid, and this was applied to both sides of the copper foil in the longitudinal direction in the same manner as in Comparative Example 5. The coating was performed one side at a time while providing an uncoated portion at regular intervals.
[0080]
Comparative Example 14
As the negative electrode mixture coating liquid, the same coating liquid as in Comparative Example 4 (solid content concentration 70% by weight, apparent viscosity 110000 mPa · S) was used on both sides of the copper foil in the longitudinal direction in the same manner as in Comparative Example 5. The coating was performed one side at a time while providing an uncoated portion at regular intervals.
[0081]
Subsequently, the coating thickness was measured in the coating sheet for positive electrodes and the coating sheet for negative electrodes respectively produced in Examples 1-24 and Comparative Examples 1-14, and the uniformity thru | or stability of coating thickness was investigated. That is, in the cross-sectional view of the coating sheet shown in FIG. _C This value (δ _C ) And coating thickness δ at 1 mm from the start of coating _S Difference δ from _CS (Δ _C −δ _S ) And δ _C And coating thickness δ at a position 1 mm before the end of coating _E Difference δ from _CE (Δ _C −δ _E ) And the length L from the start of coating until the coating thickness becomes uniform _S , And length L from uniform coating thickness to the end of coating _E Was measured respectively. In this figure, reference numeral 33 indicates an aluminum foil or a copper foil. Moreover, the application direction of the liquid is indicated by an arrow. The measurement results are shown in Table 1 and Table 2, respectively.
[0082]
[Table 1]

[Table 2]

From these tables, according to Examples 1 to 24, in each application part, the application thickness is uniform and stable from immediately after application to the end of application, and there is a good uncoated part where no electrode mixture coating solution is present. It was found that a sheet was obtained. And when the electrode was produced from these sheets and the nonaqueous electrolyte battery was manufactured by the conventional method using this, the battery performance was excellent and the battery excellent in safety | security was obtained.
[0083]
On the other hand, in the coated sheets produced in Comparative Examples 1 to 14, the state of the uncoated part was good, but the cutting of the coating liquid at the boundary between the coated part and the uncoated part was poor, and The coating layer swelled at the end, or the coating thickness became extremely thin. As a result, when the obtained application sheet was compression-molded with a roller press, the conductive base material was cut in the application sheet with the application layer raised. In addition, a battery manufactured using a coating sheet having an extremely thin coating thickness has extremely low battery performance and safety, and cannot be put to practical use.
[0084]
【The invention's effect】
As is clear from the above description, according to the present invention, a good uncoated portion in which no electrode mixture coating solution is present is stably and efficiently formed, and a sheet-shaped electrode plate with good characteristics is manufactured. Can do. And, since the uncoated part is formed at the same time as the coating of the coating liquid, it is not necessary to peel off the electrode mixture layer for tab plate welding, and labor saving and improvement of the efficiency of the coating process are achieved by reducing the number of work Can do.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing an example of a die nozzle used in the present invention.
FIG. 2 is a plan view showing a coating pattern of an electrode mixture coating solution formed on a conductive substrate according to the present invention.
FIG. 3 is a diagram schematically showing an embodiment of a coating apparatus used in the method for producing a sheet-like electrode plate of the present invention.
FIG. 4 is a view showing another installation mode of the die nozzle in the coating apparatus.
FIG. 5 is a diagram showing another example of the intermittent supply system of the coating liquid in the coating apparatus used in the present invention.
FIG. 6 is a cross-sectional view along the coating direction of a coated sheet obtained in an example of the present invention.
FIG. 7 is a cross-sectional view showing an example of the configuration of a cylindrical nonaqueous electrolyte battery.
8A and 8B are diagrams showing a conventional method of connecting a tab plate, where FIG. 8A is a front view, FIG. 8B is a rear view, and FIG. 8C is a perspective view taken along line AA in FIG.
[Explanation of symbols]
12 ......... Die nozzle
13 ... Lip
14 ... Land
15 ......... Manifold
16 ……… Electrode material (mixture) coating solution
17 ……… Conductive substrate
18 ……… Electrode mixture application part
19 ……… Unapplied part
20 ... Backup roll
22 ... …… Liquid supply system
23 ... …… Liquid solution tank
24 ......... Constant flow pump
26 ......... Discharge valve
28 ......... Return valve
29 ......... Flow meter
30 ... Inert gas
31 ......... Sealed tank

Claims (6)

In the production of a non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte,
An electrode material coating liquid having an apparent viscosity of 500 to 100,000 mPa · S (shear rate 13 sec ⁻¹ ) is discharged by a die nozzle connected to the coating liquid supply system, and is applied to the traveling conductive substrate in the longitudinal direction. After applying the coating solution while providing an unapplied portion at regular intervals , drying, press-molding the electrode material coated sheet obtained after cutting out parallel to the longitudinal direction according to the predetermined battery height, A method for producing a sheet-like electrode plate, comprising cutting out in the width direction and taking out one sheet-like electrode plate . 2. The method for producing a sheet-like electrode plate according to claim 1, wherein the uncoated portion is provided by moving the die nozzle in a direction that is substantially perpendicular to the coated surface of the conductive substrate. Wherein by moving in a direction away substantially vertically conductive substrate to the distal end surface of the die nozzle, the method for manufacturing a sheet-like plate of claim 1, wherein the provision of the uncoated portion. 2. The method for manufacturing a sheet-like electrode plate according to claim 1, wherein the uncoated portion is provided by swinging the die nozzle in a direction parallel to a running direction of the conductive substrate. 5. The sheet-like electrode plate according to claim 1, wherein in the coating liquid supply system, the uncoated portion is provided by intermittently supplying the coating liquid to the die nozzle. Manufacturing method. A non-aqueous electrolyte battery comprising a sheet-like electrode produced from a sheet-like electrode plate produced by the method according to claim 1.

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