JP2008258010A - Manufacturing device for secondary battery electrode plate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a rise at a coating starting section is generated while both ends of a boundary of a piled material applied on a core material are formed in wavelike shapes when a lubricant used for rolling remains on the surface of the aluminum solid foil of the core material for a secondary battery electrode, for example, a positive electrode, and the performance of the battery and its productivity is reduced because cracks caused by excessive compressed desity at a rolling process and the dropping-out of the piled material are generated. <P>SOLUTION: The piled material is intermittently applied on a washing section of the aluminum solid foil after degreasing and drying the aluminum solid foil by intermittently washing by water or a nonaqueous solvent (for example, an alcohol system, a ketone system, an ether system, acid, and alkali) wherein oil on the surface is decomposed by floating without giving any damage to the aluminum solid foil after rolling prior to an applying process of the piled material to the core material, and the performance and productivity of the battery is improved by avoiding the uneven application of the piled material on the aluminum solid foil. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a secondary battery electrode plate manufacturing apparatus including a pretreatment of a core material for a secondary battery electrode plate, for example, a hard aluminum foil used as a positive electrode material of a lithium ion secondary battery, and a method for manufacturing the same.

  In recent years, as a representative of non-aqueous solvent type secondary batteries used in portable electronic and communication devices such as mobile phones and notebook computers, lithium transition metal composite oxides are used as positive electrode active materials, and lithium ions can be occluded and released. Lithium ion secondary batteries using a negative carbon active material as a negative electrode active material have been put into practical use.

  A positive electrode plate paste prepared by kneading and dispersing a positive electrode active material such as a lithium-containing metal oxide, a conductive material, a binder, and a thickener is formed into a paste, for example, as shown in FIG. The coated surface 2 and the uncoated surface 3 are alternately formed on the aluminum hard foil 1 and dried, and rolled to a predetermined density, and then necessary. A positive electrode plate is produced by cutting to a width.

  When the lubricating oil used when rolling the surface of the aluminum hard foil 1 remains in the positive electrode plate produced in this way, as shown in FIG. 5 is formed, and the boundary 4 of the coating surface 2 is formed in a wave shape at both ends, and the battery performance is deteriorated due to the occurrence of cracks due to excessive densification in the rolling process and dropping of the paste for the positive electrode plate. Therefore, the hard aluminum foil 1 used as the electrode substrate is required to have a small amount of residual oil on the surface.

Therefore, pretreatment methods such as corona treatment, washing with a cleaning solution of an organic solvent, acid, alkali, etc., and oil burnout by annealing have been proposed as a degreasing method of the aluminum foil 1 or the aluminum plate that meets this demand (patent) References 1, 2).
JP 7-1335023 A Japanese Patent Laid-Open No. 2005-50679

  However, in any pretreatment method, since pretreatment must be performed in advance in a manufacturing process different from the composite material coating process, the oil remaining in the aluminum hard foil 1 diffuses over time after the treatment. Then, it may be deposited on the surface layer and contaminated by external contaminants.

  Moreover, when pre-processing for every single side | surface, the oil component of a back surface may be transcribe | transferred to a processing surface at the time of winding of the aluminum hard foil 1, and the effect of pre-processing may be lost.

  For this reason, it is necessary to perform the pretreatment immediately before the application of the paste for the positive electrode plate. However, when the pretreatment is performed on the entire surface of the aluminum hard foil 1, the wettability of the paste with respect to the aluminum hard foil 1 is improved, and the application surface Since both end portions of 2 are wet and spread, and the film thickness of the end portion of the coating surface 2 becomes thin, there is a problem that the capacity is insufficient and the electrode plate cannot be effectively used up to the end portion.

  Further, since there is no oil in the uncoated portion of the composite material, there is a problem that contaminants are easily attached and the aluminum hard foil 1 is easily contaminated.

  Therefore, the present invention has been made in view of such a technical background, and a secondary battery electrode plate in which the pretreatment of the core material can be performed in a simple process without reducing the strength and productivity of the core material. A manufacturing apparatus and a manufacturing method thereof are provided.

  An apparatus for producing a secondary battery electrode plate of the present invention produces a secondary battery comprising a positive electrode, a negative electrode, an electrode body composed of a separator interposed between the positive electrode and the negative electrode, and a nonaqueous solvent electrolyte. In the manufacturing apparatus of the secondary battery electrode plate for the above, a cleaning means for cleaning and degreasing the positive electrode or the negative electrode core material is provided in front of the application means for applying the mixture to the core material. To do.

  In the production apparatus for a secondary battery electrode plate according to the present invention, the cleaning means wipes the fat content of the core material with a fibrous wiping roll containing water or a non-aqueous solvent. is there.

  In the apparatus for manufacturing a secondary battery electrode plate according to the present invention, the washing means is characterized in that the fat content of the core material is dipped in water or a non-aqueous solvent and then wiped off with fibers.

  The apparatus for manufacturing a secondary battery electrode plate according to the present invention is characterized in that the cleaning means intermittently cleans the core material and alternately provides a cleaning portion and a non-cleaning portion on the core material. is there.

  In the manufacturing apparatus for a secondary battery electrode plate according to the present invention, the application unit applies the composite material to the cleaning portion of the core material.

  In the secondary battery electrode plate manufacturing apparatus of the present invention, the shape of the composite material applied to the cleaning portion of the core material is controlled by a difference in wettability between the cleaning portion and the non-cleaning portion of the core material. It is characterized by doing.

  In the secondary battery electrode plate manufacturing apparatus of the present invention, the core material is a hard aluminum foil.

  In the apparatus for manufacturing a secondary battery electrode plate of the present invention, the non-aqueous solvent is a solution of alcohol, ketone, ether, acid, alkali or the like.

  In the secondary battery plate manufacturing apparatus of the present invention, the surface tension at 25 ° C. of the cleaning portion of the core material is 40 mN / m or more as a wetting tension value measured by a test method of JIS-K6768. It is a feature.

  The method for producing a secondary battery electrode plate according to the present invention produces a secondary battery comprising a positive electrode, a negative electrode, an electrode body composed of a separator interposed between the positive electrode and the negative electrode, and a nonaqueous solvent electrolyte. In the manufacturing method of the secondary battery electrode plate for cleaning, the cleaning step of cleaning the core material of the positive electrode or the negative electrode and degreasing the core material is performed before the coating step of applying the mixture to the core material. It is characterized by this.

  In the method for manufacturing a secondary battery electrode plate according to the present invention, in the cleaning step, the core material is intermittently cleaned to alternately form cleaning portions and non-cleaning portions on the core material. It is.

  In the method for manufacturing a secondary battery electrode plate according to the present invention, in the application step, the composite material is applied to a cleaning portion of the core material.

  According to the manufacturing apparatus of the secondary battery electrode plate according to claim 1 of the present invention and the manufacturing method according to claim 10 of the present invention, the core material is applied by applying the mixture to the core material immediately after being washed and degreased. Since the washing part is less likely to be contaminated and the applicability and adhesion of the composite material to the core material are improved, uneven application of the composite material is drastically reduced, and the performance and productivity of the battery are improved.

  Further, according to the secondary battery electrode plate manufacturing apparatus of claim 2 or 3 of the present invention, the degreasing of the core material can be performed reliably and uniformly by a simple means, and the coating unevenness of the composite material is drastically reduced. Battery performance and productivity are improved.

  Furthermore, according to the manufacturing apparatus for a secondary battery electrode plate according to claim 4 or 5 of the present invention, by forming the cleaning part and the non-cleaning part in the core material, the wettability between the cleaning part and the non-cleaning part is improved. Since a difference arises and the curvature at the both ends of the boundary part of the composite material apply | coated to the core material and the swell of an application | coating start part are suppressed, the performance and productivity of a battery improve.

  Furthermore, according to the manufacturing apparatus for a secondary battery electrode plate according to claim 4 or 5 of the present invention, the aluminum hard foil obtained by foil rolling to degrease the aluminum hard foil excellent in the coating property and adhesion of the composite material. Since the fat content of the surface layer of the aluminum hard foil can be suspended and decomposed without reducing the strength of the aluminum foil, the coating unevenness of the composite material is drastically reduced, and the performance and productivity of the battery are further improved.

  The present invention intermittently cleans and degreases the aluminum hard foil after the foil rolling, thereby degreasing the foil without softening and improving the wettability of the foil surface. This improves the applicability of the coating.

  In addition, since it does not use an electrical pretreatment such as corona or plasma or a degreasing treatment such as a flame treatment using a spark or flame, it can be used in an explosion-proof manufacturing process in which a nonaqueous solvent is handled.

  The structure of the manufacturing apparatus of the secondary battery electrode plate of this invention is demonstrated using FIG.

  The apparatus for manufacturing a secondary battery electrode plate according to the present invention is provided with an unwinding part 6 for attaching a metal core 1 made of aluminum hard foil in the form of a hoop, and a cleaning part and a non-cleaning part are provided on the core 1 intermittently. A cleaning means 7 having a cleaning mechanism, a cleaning drying furnace 8 for evaporating the cleaning liquid adhering to the core material 1 in the cleaning means 7, and an application for intermittently applying a paste-like mixture to the core material 1 in layers. Means 9, a mixture drying furnace 10 for drying the solvent component of the mixture applied in layers to the core material 1 in the application means 9, and a winding unit 11 for winding the electrode plate into a hoop shape. The

  In order to form a mixture layer on both the front and back surfaces of the core material 1, two cleaning means 7, a cleaning drying furnace 8, a coating means 9, and a mixture drying furnace 10 are provided in the manufacturing process. The layers of the composite material are formed side by side from both the front and back surfaces of the core material 1, or the composite material layer is formed on the surface of the core material 1 and wound around the winding unit 11 once. Later, the core material 1 may be attached to the unwinding portion 6 again to form a mixture layer on the back surface of the core material 1.

  The cleaning liquid used for cleaning the core material 1 in the cleaning means 7 is water or a non-aqueous solvent (for example, alcohol-based, ketone-based, ether-based, etc.) that can float and decompose the oil on the surface layer without damaging the core material 1. Acid, alkali, etc.). In addition, since the rolling oil and chemical | medical agent used for the process of surface layer change according to the kind of metal used for the core material 1, not only a single solvent but what mixed several solvent may be used for a nonaqueous solvent.

  Furthermore, since the cleaning of the core material 1 is performed prior to the application of the composite material to the core material 1, the cleaning liquid having a low boiling point, specifically, 200 ° C. or lower is preferable. Even if the cleaning liquid has a boiling point of 200 ° C. or higher, there is no problem if it is used as long as the cleaning component does not remain at the time of applying the mixture by drying after the cleaning treatment.

  Furthermore, as a method for removing the cleaning liquid and the floating oil, if a cleaning part and an uncleaned part can be formed on the core material 1, a method of removing and collecting by temporarily scattering with a brush or air, or running the core material 1 A method of transferring to the wiping roll by resistance generated by the peripheral speed difference between the driving roll to be driven and the core member 1 and the wiping roll facing the driving roll, or a fibrous water absorption after being immersed in water or a non-aqueous solvent Any method of wiping the body in contact with the core material 1 may be used.

  By the way, the application start position of the composite material varies depending on the contact angle between the applied composite material and the core material 1, but starts from 0 to 2 mm behind from the cleaning start position of the core material 1 with respect to the traveling direction of the core material 1. .

  This is because the cleaning part of the core material 1, that is, the degreased part, has better wettability of the composite material to the core material 1 than the non-cleaning part. The rise of the material application start part is eliminated by the leveling effect of the composite material.

  Moreover, it is desirable that the application end position of the composite material with respect to the cleaning end position of the core material 1 is changed by the intermittent application method of the composite material.

  For example, as shown in FIG. 2, in the state where the mixed material is being supplied quantitatively from the tank 31 using the pump 32, the valve 33 is switched to intermittently supply the mixed material to the die 34. According to the intermittent application method, such as by switching the supply flow path for intermittently applying the material, the supply of the composite material from the tank 31 to the die 34 is blocked by the valve 33 and applied to the core material 35 at the end of the application of the composite material. The supply amount of the composite material to the application end portion of the composite material is less than the supply amount to the steady application portion between the application start end portion and the application end portion of the composite material. Since the film thickness of the composite material formed on the core material 35 tends to decrease before the end of the applied composite material is formed, the application end position of the composite material is changed from the cleaning end position of the core material 35 to the core. The back of the material 35 is 0 to 2 mm behind.

  Further, for example, as shown in FIG. 3, the gap 41 between the tip of the die 34 and the backup roll 42 is widened to cut the mixture supplied from the die 34, thereby terminating the application of the mixture onto the core member 35. According to the intermittent application method by position control for forming the portion, the composite material stretched between the die 34 and the core material 35 when the gap 41 is widened is stacked on the application end portion of the composite material applied to the core material 1. Since the film thickness of the composite material at the coating end portion tends to rise from the steady application portion between the application start end portion and the application end portion of the composite material, the application end position of the composite material is the end of the cleaning of the core material 35. From the position, it is 0 to 2 mm before the traveling direction of the core member 35.

  Further, if the film thickness of the end portion of the composite material in the width direction perpendicular to the traveling direction of the core material 35 is increased, the cleaning portion of the core material 35 is set wider than the application portion of the composite material, If the film thickness of the end portion of the core material 35 is reduced, the cleaning portion of the core material 35 is set narrower than the application portion of the composite material, thereby reducing the film thickness of the composite material applied to the core material 35 to the end portion. It can be formed uniformly.

  The relationship between the cleaning start position of the core material 35 and the application start position of the composite material, and the relationship between the cleaning end position of the core material 35 and the application end position of the composite material are as follows. This depends on the wettability between the core material 35 and the composite material, and this wettability is the value of the surface tension at 25 ° C. (hereinafter referred to as “wetting”) of the washed portion of the core material 35 measured by the test method of JIS-K6768. It is defined as “tension value”.

  The aluminum hard foil used as the core material 1 or 35 of the present invention does not limit the contact angle with the foil application or wettability test solution, but when used as an electrode base material for a lithium ion secondary battery, In order to ensure the applicability of the material, it is preferable to use a material having a wetting tension value of 40 mN / m or more, particularly 45 mN / m or more.

  Further, as the wettability test solution, a mixed solution of ethylene glycol monoethyl ether and formamide was used. However, the present invention is not limited to the above-described wettability test or the aluminum hard foil defined by such wettability test. Is not to be excluded.

  An embodiment of the present invention will be described, but the present invention is not limited to this embodiment.

  As a core material 1 or core material 35 of Examples 1 to 3 or Comparative Examples 1 and 2, an aluminum hard foil having a thickness of 15 μm formed by hot rolling, cold rolling and foil rolling on an ingot based on JIS-A1085 Is used. The aluminum hard foil obtained by this foil rolling corresponds to H18 material.

  Next, in Examples 1 to 3 and Comparative Examples 1 and 2, the core material 1 or core material 35 made of this hard aluminum foil was pretreated according to the conditions of (Table 1) and rolled, and then the mixture was applied. A positive electrode plate was formed by slitting a predetermined width from a position 1 mm inside the width, and then wound together with a negative electrode plate / separator to form a battery.

  Three examples of Examples 1 to 3 in which the pretreatment for cleaning so that the shape of the cleaning portion of the core material 1 or the core material 35 is a predetermined shape are applied in accordance with the conditions of (Table 1). The width and application start position were adjusted.

  Two examples, Comparative Example 1 without pretreatment and Comparative Example 2 in which pretreatment in which the entire surface of the core material 1 or the core material 35 is continuously treated with a corona, are applied to the core material 1 or the core material 35. The material application width was 500 mm and the thickness was 100 μm.

  Therefore, in the layer of the composite material formed on the core material 1 or the core material 35 in this way, as shown in FIG. 4, the width of the layer is 2 mm from the end in the width direction with respect to the coating width A of the layer and the thickness of the center portion of the layer. The thickness B of the position, the thickness C of the end portion of the coating start portion at a position 3 mm from the coating start position of the layer, the position of the width direction end portion of the cleaning portion of the core material 1 or the core material 35 and the width of the layer of the composite material The results of measuring the width D with respect to the position of the direction end, and the width E between the cleaning start position of the cleaning portion of the core material 1 or the core material 35 and the coating start position of the mixture layer are as shown in Table 1. is there.

（表１）に示すように、所定の条件で前処理した実施例１ないし３と前処理をしない比較例１とを比較すると、比較例１は芯材１または芯材３５と合材との濡れ性が悪いため、合材の塗布巾Ａの収縮が見られ、また、合材の塗布開始部の端部の厚みＣも同様の理由で実施例１ないし３よりも比較例１のほうが大きくなった。

As shown in (Table 1), when Examples 1 to 3 that were pretreated under a predetermined condition were compared with Comparative Example 1 that was not pretreated, Comparative Example 1 was the result of core material 1 or core material 35 and composite material. Since the wettability is poor, shrinkage of the application width A of the composite material is seen, and the thickness C of the end portion of the application start portion of the composite material is larger in Comparative Example 1 than in Examples 1 to 3 for the same reason. became.

  Further, in Comparative Example 2 where the entire surface of the core material 1 or the core material 35 is treated with corona, the wettability between the core material 1 or the core material 35 and the composite material is so good that it spreads wet. The thickness B and the thickness C at the end of the coating start portion were reduced.

  Next, the manufacturing method of the positive electrode plate of the lithium ion secondary battery which uses aluminum hard foil as a base material for electrodes is demonstrated.

First, LiCoO ₂ powder 95 weight part as a cathode active material, 4 parts by weight of PTFE50 parts aqueous solution as a binder to 5 parts by weight of acetylene black as a conductive material, relative to 1 part by weight of carboxymethyl cellulose as a thickening agent By mixing and dispersing 30 parts by weight of an aqueous solution dissolved in 99 parts by weight of water, a paste-like composite material for a positive electrode is obtained.

  Therefore, the positive electrode composite material is intermittently applied to both surfaces of the core material 1 or the core material 35 with a thickness of 100 μm along the rolling direction (longitudinal direction) of the core material 1 or the core material 35 by the applying means 9. As shown in FIG. 1, the coated portion 2 and the uncoated portion 3 are formed alternately on the core material 1 or the core material 35.

  After applying the positive electrode mixture to the core material 1 or the core material 35 by the application means 9, after drying at 150 ° C. for 15 minutes in the compound material drying furnace 10, the application part 2 is observed. In Nos. 3 and 3, the curve of the boundary part 4 as shown in FIG. 5 and the rising part 5 of the application start part were not recognized.

  On the other hand, in Comparative Example 1, bending and bulging, which are considered to be caused by insufficient degreasing, were observed.

  Furthermore, each step of pressing, slitting, and cutting was performed on the core material 1 or the core material 35 of the example 3 and the comparative examples 1 and 2 to obtain a positive electrode plate of a lithium ion secondary battery.

  For the evaluation, only the row cut to a predetermined distance from the part 2 mm inside from the coating width is used, and the evaluation is performed by the linearity of the endmost row, the occurrence frequency of the electrode plate cracking during rolling, and the initial capacity. went.

  At this time, on the negative electrode plate, 100 parts by weight of carbon powder obtained by heat-treating coke and 1 part by weight of CMC were suspended in ion-exchanged water to form a paste, and then the fluororesin binder polytetrafluoroethylene was used. A paste formed by mixing 10 parts by weight is applied to both sides of a 10 μm thick copper foil using a die coat, dried with hot air at 130 ° C., rolled to a predetermined thickness, and the lead is welded. What was done was used.

  In addition, a polyethylene non-woven fabric is used for the separator, and the electrolyte is one dissolved in an equal volume mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) at a rate of 1 mol / l lithium hexafluorophosphate. A test battery was prepared by injecting a predetermined amount of electrolyte and sealing the battery.

  A charge / discharge cycle test was performed on the obtained test battery. Charging was performed at a constant current of 500 mA, and when the voltage reached 4.1 V, the charging was switched to constant voltage charging at 4.1 V, and charging was performed for a total of 2 hours.

  Discharging was performed at 20 ° C. and 720 mA. When the discharging potential reached 3.0 V, discharging was terminated and the next charging was started. When 30 cycles of charge and discharge were repeated, no change in capacity was observed in Examples 2 and 3, and good cycle characteristics were confirmed. Each evaluation result is shown in (Table 2).

なお、本実施例では、正極用合材とアルミニウム硬箔とを用いた例で説明したが、正極用合材とニッケル箔あるいは負極用合材と銅箔とを用いても同様の効果が得られる。

In addition, although the present Example demonstrated by the example using the positive mix and aluminum hard foil, even if it uses the positive mix and nickel foil or the negative mix and copper foil, the same effect is acquired. It is done.

  As in the present invention, it is possible to uniformly degrease rolled fat in a short time by intermittently washing and degreasing the core material prior to the intermittent application process of the mixture to the core material. As a result, uneven application of the mixture to the core material is drastically reduced, and the performance and productivity of the battery are dramatically improved.

Schematic diagram of secondary battery manufacturing apparatus of the present invention Schematic diagram of intermittent application by flow path switching method in secondary battery manufacturing apparatus of the present invention Schematic diagram of intermittent application by position control method in secondary battery manufacturing apparatus of the present invention Explanatory drawing of the positional relationship of the washing | cleaning part and application | coating part in the secondary battery manufacturing apparatus of this invention Schematic diagram showing the state of paste applied to a hard aluminum foil that is not sufficiently degreased by a conventional secondary battery manufacturing device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core material 2 Application | coating part 3 Unapplication | coating part 4 Boundary part 5 Swelling part 6 Unwinding part 7 Cleaning means 8 Cleaning drying furnace 9 Application means 10 Mixing material drying furnace 11 Winding part 31 Tank 32 Pump 33 Valve 34 Die 35 Core 41 Gap 42 Backup roll

Claims (12)

  In an apparatus for producing a secondary battery electrode plate for producing a secondary battery comprising an electrode body comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a nonaqueous solvent-based electrolyte, An apparatus for manufacturing a secondary battery electrode plate, wherein cleaning means for cleaning and degreasing the positive electrode or the negative electrode core material is provided in front of an application means for applying a mixture to the core material.   The said washing | cleaning means wipes off the fat of the said core material with the fibrous roll containing water or a non-aqueous solvent, The manufacturing apparatus of the secondary battery electrode board of Claim 1 characterized by the above-mentioned.   2. The apparatus for manufacturing a secondary battery electrode plate according to claim 1, wherein the cleaning means wipes the fat content of the core material with fibers after soaking it in water or a non-aqueous solvent.   The secondary according to any one of claims 1 to 3, wherein the cleaning means intermittently cleans the core material to alternately form a cleaning portion and a non-cleaning portion on the core material. Battery plate manufacturing equipment.   The said application | coating means apply | coats the said composite material to the said washing | cleaning part of the said core material, The manufacturing apparatus of the secondary battery electrode board of Claim 4 characterized by the above-mentioned.   The secondary material according to claim 4, wherein the shape of the composite material applied to the cleaning portion of the core material is controlled by a difference in wettability between the cleaning portion and the non-cleaning portion of the core material. Battery plate manufacturing equipment.   The secondary battery electrode plate manufacturing apparatus according to any one of claims 1 to 4, wherein the core material is one of hard aluminum foil, nickel foil, and copper foil.   4. The apparatus for manufacturing a secondary battery electrode plate according to claim 1, wherein the non-aqueous solvent is an alcohol-based, ketone-based, ether-based, acid, alkali, or the like solution.   9. The secondary battery electrode plate according to claim 8, wherein a surface tension of the cleaning portion of the core material at 25 ° C. is 40 mN / m or more in terms of a wetting tension value measured by a test method of JIS-K6768. Manufacturing equipment.   In a method for producing a secondary battery electrode plate for producing a secondary battery comprising a positive electrode, a negative electrode, an electrode body comprising a separator interposed between the positive electrode and the negative electrode, and a nonaqueous solvent-based electrolyte, Manufacturing of a secondary battery electrode plate, wherein a cleaning step of cleaning the core material of the positive electrode or the negative electrode and degreasing the core material is performed before a coating step of applying a mixture to the core material. Method.   11. The method of manufacturing a secondary battery electrode plate according to claim 10, wherein in the cleaning step, the core material is intermittently cleaned to alternately form cleaning portions and non-cleaning portions on the core material.   The method of manufacturing a secondary battery electrode plate according to claim 11, wherein in the application step, the composite material is applied to a cleaning portion of the core material.

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